BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diff...BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diffusion models for liver fibrosis in one cohort.AIM To evaluate the clinical potential of six diffusion-weighted models in liver fibrosis staging and compare their diagnostic performances.METHODS This prospective study enrolled 59 patients suspected of liver disease and scheduled for liver biopsy and 17 healthy participants.All participants underwent multi-b value DWI.The main DWI-derived parameters included Mono-apparent diffusion coefficient(ADC)from mono-exponential DWI,intravoxel incoherent motion model-derived true diffusion coefficient(IVIM-D),diffusion kurtosis imaging-derived apparent diffusivity(DKI-MD),stretched exponential model-derived distributed diffusion coefficient(SEM-DDC),fractional order calculus(FROC)model-derived diffusion coefficient(FROC-D)and FROC model-derived microstructural quantity(FROC-μ),and continuous-time random-walk(CTRW)model-derived anomalous diffusion coefficient(CTRW-D)and CTRW model-derived temporal diffusion heterogeneity index(CTRW-α).The correlations between DWI-derived parameters and fibrosis stages and the parameters’diagnostic efficacy in detecting significant fibrosis(SF)were assessed and compared.RESULTS CTRW-D(r=-0.356),CTRW-α(r=-0.297),DKI-MD(r=-0.297),FROC-D(r=-0.350),FROC-μ(r=-0.321),IVIM-D(r=-0.251),Mono-ADC(r=-0.362),and SEM-DDC(r=-0.263)were significantly correlated with fibrosis stages.The areas under the ROC curves(AUCs)of the combined index of the six models for distinguishing SF(0.697-0.747)were higher than each of the parameters alone(0.524-0.719).The DWI models’ability to detect SF was similar.The combined index of CTRW model parameters had the highest AUC(0.747).CONCLUSION The DWI models were similarly valuable in distinguishing SF in patients with liver disease.The combined index of CTRW parameters had the highest AUC.展开更多
BACKGROUND Chronic hepatitis C(CHC)is a health burden with consequent morbidity and mortality.Liver biopsy is the gold standard for evaluating fibrosis and assessing disease severity and prognostic purposes post-treat...BACKGROUND Chronic hepatitis C(CHC)is a health burden with consequent morbidity and mortality.Liver biopsy is the gold standard for evaluating fibrosis and assessing disease severity and prognostic purposes post-treatment.Noninvasive altern-atives for liver biopsy such as transient elastography(TE)and diffusion-weighted magnetic resonance imaging(DW-MRI)are critical needs.AIM To evaluate TE and DW-MRI as noninvasive tools for predicting liver fibrosis in children with CHC.METHODS This prospective cross-sectional study initially recruited 100 children with CHC virus infection.Sixty-four children completed the full set of investigations including liver stiffness measurement(LSM)using TE and measurement of apparent diffusion coefficient(ADC)of the liver and spleen using DW-MRI.Liver biopsies were evaluated for fibrosis using Ishak scoring system.LSM and liver and spleen ADC were compared in different fibrosis stages and correlation analysis was performed with histopathological findings and other laboratory parameters.RESULTS Most patients had moderate fibrosis(73.5%)while 26.5%had mild fibrosis.None had severe fibrosis or cirrhosis.The majority(68.8%)had mild activity,while only 7.8%had moderate activity.Ishak scores had a significant direct correlation with LSM(P=0.008)and were negatively correlated with both liver and spleen ADC but with no statistical significance(P=0.086 and P=0.145,respectively).Similarly,histopatho-logical activity correlated significantly with LSM(P=0.002)but not with liver or spleen ADC(P=0.84 and 0.98 respectively).LSM and liver ADC were able to significantly discriminate F3 from lower fibrosis stages(area under the curve=0.700 and 0.747,respectively)with a better performance of liver ADC.CONCLUSION TE and liver ADC were helpful in predicting significant fibrosis in children with chronic hepatitis C virus infection with a better performance of liver ADC.展开更多
Objective： The aim of our study was to analysis the pictures of conventional magnetic resonance imaging （MR）, diffusion-weighted imaging （DWl） and dynamic enhanced magnetic resonance imaging （DEMRI） of pancreat...Objective： The aim of our study was to analysis the pictures of conventional magnetic resonance imaging （MR）, diffusion-weighted imaging （DWl） and dynamic enhanced magnetic resonance imaging （DEMRI） of pancreatic endocrine tumors （PETs）, and evaluate diagnostic value of MR, DWl and DEMRI for diagnosing PETs. Methods： DWl and DEMRI scanning toward 13 patients with PETs being confirmed by surgical pathology before surgery on the basis of conventional MR scanning were carried out, and MR findings was analyzed retrospectively. Results： Of 13 patients with PETs there was 11 cases with single lesion, 2 with multiple, and had 15 lesions altogether, of which there were 3 lesions in pancreatic head, 1 in its neck, 2 in its body, 4 in its body and tail, 5 in its tail. MR findings： （1） T1WI signal was low or slightly lower （9/15）, and equal ones （5/15）; （2） T2WI showed high or slightly higher signal （10/15）, and equal ones （5/15）; （3） T1WI with fat suppression： the signal was low （11/15）, mixed signal （2/15）, and equal ones （2/15）; （4） DWI： normal pancreatic tissue exhibited homogeneous intermediate signal, all 15 lesions were high or slightly higher signal, the measured ADC values of tissue of PETs was （1.124 ± 0.252） × 104 mm2/s, and the ADC value of normal pancreatic tissue （1.873 ± 0.157） × 10^3 mm2/s; （5） Enhanced （M3D/LAVA） scanning： among 13 patients with PETs there were 12 pancreatic lesions with significantly enhanced signals in the arterial phase in all 15, and significantly higher than normal pancreatic tissue, and two slight enhancement was slightly higher signal; and 1 no enhancement. Enhanced pattern： homogeneous enhancement were 6 lesions, and the heterogeneous 4, and the edge ring 5. Conclusion： MR and DWl combining with DEMRI help qualitative diagnosis of pancreatic endocrine tumors.展开更多
Moderate to severe perinatal hypoxic-ischemic encephalopathy occurs in~1 to 3/1000 live births in high-income countries and is associated with a significant risk of death or neurodevelopmental disability.Detailed asse...Moderate to severe perinatal hypoxic-ischemic encephalopathy occurs in~1 to 3/1000 live births in high-income countries and is associated with a significant risk of death or neurodevelopmental disability.Detailed assessment is important to help identify highrisk infants,to help families,and to support appropriate interventions.A wide range of monitoring tools is available to assess changes over time,including urine and blood biomarkers,neurological examination,and electroencephalography.At present,magnetic resonance imaging is unique as although it is expensive and not suited to monitoring the early evolution of hypoxic-ischemic encephalopathy by a week of life it can provide direct insight into the anatomical changes in the brain after hypoxic-ischemic encephalopathy and so offers strong prognostic information on the long-term outcome after hypoxic-ischemic encephalopathy.This review investigated the temporal dynamics of neonatal hypoxic-ischemic encephalopathy injuries,with a particular emphasis on exploring the correlation between the prognostic implications of magnetic resonance imaging scans in the first week of life and their relationship to long-term outcome prediction,particularly for infants treated with therapeutic hypothermia.A comprehensive literature search,from 2016 to 2024,identified 20 pertinent articles.This review highlights that while the optimal timing of magnetic resonance imaging scans is not clear,overall,it suggests that magnetic resonance imaging within the first week of life provides strong prognostic accuracy.Many challenges limit the timing consistency,particularly the need for intensive care and clinical monitoring.Conversely,although most reports examined the prognostic value of scans taken between 4 and 10 days after birth,there is evidence from small numbers of cases that,at times,brain injury may continue to evolve for weeks after birth.This suggests that in the future it will be important to explore a wider range of times after hypoxic-ischemic encephalopathy to fully understand the optimal timing for predicting long-term outcomes.展开更多
In this editorial,we comment on the article by Lambert et al,published in the recent issue of the World Journal of Radiology.The focus of the editorial is to explore the advancements in whole-body magnetic resonance i...In this editorial,we comment on the article by Lambert et al,published in the recent issue of the World Journal of Radiology.The focus of the editorial is to explore the advancements in whole-body magnetic resonance imaging(WB-MRI)techno-logy,its current clinical applications,and the challenges that must be addressed to fully realize its potential in oncological imaging.WB-MRI has emerged as a pivotal tool in oncological imaging,offering comprehensive disease assessment without ionizing radiation.Its applications span the detection of bone metastases,evaluation of hematologic malignancies,and staging of a wide range of cancers,including lymphoma,prostate,and breast cancers.Advanced techniques such as diffusion-weighted imaging have enhanced its diagnostic performance by pro-viding superior lesion-to-background contrast and quantitative metrics.Despite its diagnostic strengths,WB-MRI faces challenges in standardization,patient acceptance,and integration into clinical workflows.Variability in acquisition pro-tocols,hardware differences,and patient-related factors,such as anxiety and motion artifacts,have limited widespread adoption.Emerging guidelines like MET-RADS-P and ONCO-RADS aim to address these issues by promoting stan-dardized protocols tailored to specific clinical needs.This editorial explores the advancements in WB-MRI technology,its current clinical applications,and the barriers that must be overcome to maximize its utility.By addressing these cha-llenges and embracing standardization,WB-MRI holds the potential to redefine the landscape of oncological imaging,aligning diagnostic precision with modern treatment goals of reducing long-term patient risk.展开更多
The parafoveal area,with its high concentration of photoreceptors andfine retinal capillaries,is crucial for central vision and often exhibits early signs of pathological changes.The current adaptive optics scanning l...The parafoveal area,with its high concentration of photoreceptors andfine retinal capillaries,is crucial for central vision and often exhibits early signs of pathological changes.The current adaptive optics scanning laser ophthalmoscope(AOSLO)provides an excellent tool to acquire accurate and detailed information about the parafoveal area with cellular resolution.However,limited by the scanning speed of two-dimensional scanning,thefield of view(FOV)in the AOSLO system was usually less than or equal to 2,and the stitching for the parafoveal area required dozens of images,which was time-consuming and laborious.Unfortunately,almost half of patients are unable to obtain stitched images because of their poorfixation.To solve this problem,we integrate AO technology with the line-scan imaging method to build an adaptive optics line scanning ophthalmoscope(AOLSO)system with a larger FOV.In the AOLSO,afocal spherical mirrors in pairs are nonplanar arranged and the distance and angle between optical elements are optimized to minimize the aberrations,two cylinder lenses are orthogonally placed before the imaging sensor to stretch the point spread function(PSF)for sufficiently digitizing light energy.Captured human retinal images show the whole parafoveal area with 55FOV,60 Hz frame rate and cellular resolutions.Take advantage of the 5FOV of the AOLSO,only 9 frames of the retina are captured with several minutes to stitch a montage image with an FOV of 99,in which photoreceptor counting is performed within approximately 5eccentricity.The AOLSO system not only provides cellular resolution but also has the capability to capture the parafoveal region in a single frame,which offers great potential for noninvasive studying of the parafoveal area.展开更多
AIM： To evaluate the utility of diffusion-weighted imaging （DWl） in screening and differential diagnosis of benign and malignant focal hepatic lesions. METHODS： Magnetic resonance imaging （MRI） examinations were...AIM： To evaluate the utility of diffusion-weighted imaging （DWl） in screening and differential diagnosis of benign and malignant focal hepatic lesions. METHODS： Magnetic resonance imaging （MRI） examinations were performed using the Signa Excite Xl Twin Speed 1.5T system （GE Healthcare, Milwaukee, Wl, USA）. Seventy patients who had undergone MRI of the liver [29 hepatocellular carcinomas （HCC）, four cholangiocarcinomas, 34 metastatic liver cancers, 10 hemangiomas, and eight cysts] between April 2004 and August 2008 were retrospectively evaluated. Visualization of lesions, relative contrast ratio （RCR）, and apparent diffusion coefficient （ADC） were compared between benign and malignant lesions on DWl. Su- perparamagnetic iron oxide （SPIO） was administered to 59 patients, and RCR was compared pre- and postadministration.RESULTS： DWI showed higher contrast between malignant lesions （especially in multiple small metastatic cancers） and surrounding liver parenchyma than did contrast-enhanced computed tomography. ADCs （mean±SD × 10^-3 mm2/s） were significantly lower （P 〈 0.05） in malignant lesions （HCC： 1.31 ± 0.28 and liver metastasis： 1.11 ± 0.22） and were significantly higher in benign lesions （hemangioma： 1.84 ± 0.37 and cyst： 2.61 ± 0.45） than in the surrounding hepatic tissues. RCR between malignant lesions and surrounding he- patic tissues significantly improved after SPIO administration, but RCRs in benign lesions were not improved.CONCLUSION： DWI is a simple and sensitive method for screening focal hepatic lesions and is useful for differential diagnosis.展开更多
Diffusion-weighted imaging (DWI) is an established diagnostic method of acute stroke. The latest advances in magnetic resonance imaging (MRI) technology have greatly expanded the utility of DWI in the examination of v...Diffusion-weighted imaging (DWI) is an established diagnostic method of acute stroke. The latest advances in magnetic resonance imaging (MRI) technology have greatly expanded the utility of DWI in the examination of various organs. Recent studies have revealed the usefulness of DWI for imaging of the liver, kidney, ovary, and breast. We report a patient with acute pancreatitis detected by DWI and discussed the efficacy of DWI in diagnosing acute pancreatitis. A 50-year old man presented with a primary complaint of abdominal pain. We performed both DWI and computed tomography (CT) for this patient. The signal intensity in a series of DWI was measured and the apparent diffusion coefficient (ADC) values were calculated to differentiate inflammation from normal tissue. Two experienced radiologists evaluated the grade of acute pancreatitis by comparing the CT findings. Initially, the pancreas and multiple ascites around the pancreas produced a bright signal and ADC values were reduced on DWI. As the inflammation decreased, the bright signal faded to an iso-signal and the ADC values returned to their normal level. There was no difference in the abilities of DWI and CT images to detect acute pancreatitis. However, our case indicates that DWI can evaluate the manifestations of acute pancreatitis using no enhancement material andhas the potential to replace CT as a primary diagnostic strategy for acute pancreatitis.展开更多
BACKGROUND The Liver Imaging Reporting and Data System(LI-RADS), supported by the American College of Radiology(ACR), has been developed for standardizing the acquisition, interpretation, reporting, and data collectio...BACKGROUND The Liver Imaging Reporting and Data System(LI-RADS), supported by the American College of Radiology(ACR), has been developed for standardizing the acquisition, interpretation, reporting, and data collection of liver imaging examinations in patients at risk for hepatocellular carcinoma(HCC). Diffusionweighted imaging(DWI), which is described as an ancillary imaging feature of LI-RADS, can improve the diagnostic efficiency of LI-RADS v2017 with gadoxetic acid-enhanced magnetic resonance imaging(MRI) for HCC.AIM To determine whether the use of DWI can improve the diagnostic efficiency of LIRADS v2017 with gadoxetic acid-enhanced magnetic resonance MRI for HCC.METHODS In this institutional review board-approved study, 245 observations of high risk of HCC were retrospectively acquired from 203 patients who underwent gadoxetic acid-enhanced MRI from October 2013 to April 2018. Two readers independently measured the maximum diameter and recorded the presence of each lesion and assigned scores according to LI-RADS v2017. The test was used to determine the agreement between the two readers with or without DWI. In addition, the sensitivity(SE), specificity(SP), accuracy(AC), positive predictive value(PPV), and negative predictive value(NPV) of LI-RADS were calculated.Youden index values were used to compare the diagnostic performance of LIRADS with or without DWI.RESULTS Almost perfect interobserver agreement was obtained for the categorization of observations with LI-RADS(kappa value: 0.813 without DWI and 0.882 with DWI). For LR-5, the diagnostic SE, SP, and AC values were 61.2%, 92.5%, and71.4%, respectively, with or without DWI; for LR-4/5, they were 73.9%, 80%, and75.9% without DWI and 87.9%, 80%, and 85.3% with DWI; for LR-4/5/M, they were 75.8%, 58.8%, and 70.2% without DWI and 87.9%, 58.8%, and 78.4% with DWI; for LR-4/5/TIV, they were 75.8%, 75%, and 75.5% without DWI and 89.7%,75%, and 84.9% with DWI. The Youden index values of the LI-RADS classification without or with DWI were as follows: LR-4/5: 0.539 vs 0.679; LR-4/5/M: 0.346 vs 0.467; and LR-4/5/TIV: 0.508 vs 0.647.CONCLUSION LI-RADS v2017 has been successfully applied with gadoxetate-enhanced MRI for patients at high risk for HCC. The addition of DWI significantly increases the diagnostic efficiency for HCC.展开更多
AIM: To investigate dynamic characteristics and pathological mechanism of signal in rabbit VX-2 tumor model on diffusion-weighted imaging (DWI) after chemoembolization. METHODS: Forty New Zealand rabbits were included...AIM: To investigate dynamic characteristics and pathological mechanism of signal in rabbit VX-2 tumor model on diffusion-weighted imaging (DWI) after chemoembolization. METHODS: Forty New Zealand rabbits were included in the study and forty-seven rabbit VX-2 tumor models were raised by implanting directly and intrahepatically after abdominal cavity opened. Forty VX-2 tumor models from them were divided into four groups. DWI was performed periodically and respectively for each group after chemoembolization. All VX-2 tumor samples of each group were studied by pathology. The distinction of VX-2 tumors on DWI was assessed by their apparent diffusion coefficient (ADC) values. The statistical significance between different time groups, different area groups or different b-value groups was calculated by using SPSS12.0 software. RESULTS: Under b-value of 100 s/mm2, ADC values were lowest at 16 h after chemoembolization in area of VX-2 tumor periphery, central, and normal liver parenchyma around tumor, but turned to increase with further elongation of chemoembolization treatment. The distinction of ADC between different time groups was significant respectively (F = 7.325, P < 0.001; F = 2.496, P < 0.048; F = 6.856, P < 0.001). Cellular edema in the area of VX-2 tumor periphery or normal liver parenchyma around tumor, increased quickly in sixteen h after chemoembolization but, from the 16th h to the 48th h, cellular edema in the area of normal liver parenchyma around tumor decreased gradually and that in the area of VX-2 tumor periphery decreased lightly at, and then increased continually. After chemoembolization, Cellular necrosis in the area of VX-2 tumor periphery was more significantly high than that before chemoembolization. The areas of dead cells in VX-2 tumors manifested low signal and high ADC value, while the areas of viable cells manifested high signal and low ADC value. CONCLUSION: DWI is able to detect and differentiate tumor necrotic areas from viable cellular areas before and after chemoembolization. ADC of normal liver parenchyma and VX-2 tumor are influenced by intracellular edema, tissue cellular death and microcirculation disturbance after chemoembolization.展开更多
AIM: To investigate whether intra-procedural diffusion- weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (HCC) during trans- catheter arterial chemoembolization (TACE). METHODS: Six...AIM: To investigate whether intra-procedural diffusion- weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (HCC) during trans- catheter arterial chemoembolization (TACE). METHODS: Sixteen patients (15 male), aged 59 ±11 years (range: 42-81 years) underwent a total of 21 separate treatments for unresectable HCC in a hybrid magnetic resonance/interventional radiology suite. Ana- tomical imaging and diffusion-weighted imaging (b = 0, 500 s/mm2) were performed on a 1.5-T unit. Tumor enhancement and apparent diffusion coefficient (ADC, mm2/s) values were assessed immediately before and at 1 and 3 mo after TACE. We calculated the percent change (PC) in ADC values at all time points. We compared follow-up ADC values to baseline values using a paired t test (α = 0.05). RESULTS: The intra-procedural sensitivity, specificity, and positive and negative predictive values (%) for detecting a complete or partial 1-mo tumor response using ADC PC thresholds of ±5%, ±10%, and ±15% were 77, 67, 91, and 40; 54, 67, 88, and 25; and 46, 100, 100, and 30, respectively. There was no clear predictive value for the 3-mo follow-up. Compared to baseline, the immediate post-procedure and 1-mo mean ADC values both increased; the latter obtaining statistical significance (1.48 ± 0.29 mm2/s vs 1.65 ± 0.35 × 10-3 mm2/s, P < 0.014). CONCLUSION: Intra-procedural ADC changes of > 15% predicted 1-mo anatomical HCC response with the greatest accuracy, and can provide valuable feedback at the time of TACE.展开更多
Diffusion-weighted magnetic resonance imaging(DWI)is a well established method for the evaluation of intracranial diseases,such as acute stroke.DWI for extracranial application is more difficult due to physiological m...Diffusion-weighted magnetic resonance imaging(DWI)is a well established method for the evaluation of intracranial diseases,such as acute stroke.DWI for extracranial application is more difficult due to physiological motion artifacts and the heterogeneous composition of the organs.However,thanks to the newer technical development of DWI,DWI has become increasingly used over the past few years in extracranial organs including the abdomen and pelvis.Most previous studies of DWI have been limited to the evaluation of diffuse parenchymal abnormalities and focal lesions in abdominal organs,whereas there are few studies about DWI for the evaluation of the biliopancreatic tract.Although further studies are needed to determine its performance in evaluating bile duct,gallbladder and pancreas diseases,DWI has potential in the assessment of the functional information on the biliopancreatic tract concerning the status of tissue cellularity,because increased cellularity is associated with impeded diffusion,as indicated by a reduction in the apparent diffusion coefficient.The detection of malignant lesions and their differentiation from benign tumor-like lesions in the biliopancreatic tract could be improved using DWI in conjunction with findings obtained with conventional magnetic resonance cholagiopancreatography.Additionally,DWI can be useful for the assessment of the biliopancreatic tract in patients with renal impairment because contrast-enhanced computed tomography or magnetic resonance scans should be avoided in these patients.展开更多
AIM:To evaluate the clinical value of diffusion-weighted magnetic resonance imaging(DW-MRI)in predicting the response of rectal cancer to neoadjuvant chemoradiation.METHODS:This prospective study was approved by our i...AIM:To evaluate the clinical value of diffusion-weighted magnetic resonance imaging(DW-MRI)in predicting the response of rectal cancer to neoadjuvant chemoradiation.METHODS:This prospective study was approved by our institutional review board,and informed consent was obtained from each patient.Fifteen patients(median age 56 years)with locally advanced rectal cancer were treated in our hospital from June 2006 to December 2007.All patients were stageⅢB-C according to the results of MRI and endorectal ultrasound examinations.All patients underwent pelvic irradiation with 45 Gy/25 fx per 35 days.The concurrent chemotherapy regimen consisted of capecitabine 625mg/m2,bid(Monday-Friday),and oxaliplatin 50 mg/m2,weekly.The patients underwent surgery 5-8 wk after the completion of neoadjuvant therapy.T downstaging was defined as the downstaging of the tumor from cT3to ypT0-2 or from cT4 to ypT0-3.Good regression was defined as TRG 3-4,and poor regression was defined as TRG 0-2.Diffusion-weighted magnetic resonance images were obtained prior to and weekly during the course of neoadjuvant chemoradiation,and the apparent diffusion coefficient(ADC)values were calculated from the acquired tumor images.RESULTS:Comparison with the mean pretreatment tumor ADC revealed an increase in the mean tumor ADC during the course of neoadjuvant chemoradiation,especially at the 2ndweek(P=0.004).We found a strong negative correlation between the mean pretreatment tumor ADC and tumor regression after neoadjuvant chemoradiation(P=0.021).In the T downstage and tumor regression groups,we found a significant increase in the mean ADC at the 2ndweek of neoadjuvant therapy(P=0.011;0.004).CONCLUSION:DW-MRI might be a valuable clinical tool to help predict or assess the response of rectal cancer to neoadjuvant chemoradiation at an early timepoint.展开更多
Diffusion-weighted imaging (DWI) is one of the magnetic resonance imaging (MRI) sequences providing qualitative as well as quantitative information at a cellular level. It has been widely used for various applications...Diffusion-weighted imaging (DWI) is one of the magnetic resonance imaging (MRI) sequences providing qualitative as well as quantitative information at a cellular level. It has been widely used for various applications in the central nervous system. Over the past decade, various extracranial applications of DWI have been increasingly explored, as it may detect changes even before signal alterations or morphological abnormalities become apparent on other pulse sequences. Initial results from abdominal MRI applications are promising, particularly in oncological settings and for the detection of abscesses. The purpose of this article is to describe the clinically relevant basic concepts of DWI, techniques to perform abdominal DWI, its analysis and applications in abdominal visceral MR imaging, in addition to a brief overview of whole body DWI MRI.展开更多
Objective： To investigate the role of apparent diffusion coefficient （ADC） from diffusion-weighted magnetic resonance imaging （DW-MRI） when applied to the 7th TNM classification in the staging and prognosis of ga...Objective： To investigate the role of apparent diffusion coefficient （ADC） from diffusion-weighted magnetic resonance imaging （DW-MRI） when applied to the 7th TNM classification in the staging and prognosis of gastric cancer （GC）. Methods： Between October 2009 and May 2014, a total of 89 patients with non-metastatic, biopsy proven GC underwent 1.5T DW-MRI, and then treated with radical surgery. Tumor ADC was measured retrospectively and compared with final histology following the 7th TNM staging （local invasion, nodal involvement and according to the different groups -- stage Ⅰ, Ⅱ and Ⅲ）. Kaplan-Meier curves were also generated. The follow-up period is updated to May 2016. Results： Median follow-up period was 33 months and 45/89 （51%） deaths from GC were observed. ADC was significantly different both for local invasion and nodal involvement （P〈0.001）. Considering final histology as the reference standard, a preoperative ADC cut-offof 1.80×10-3 mm^2/s could distinguish between stages I and Ⅱ and an ADC value of ≤1.36-10-3 mm^2/s was associated with stage Ⅲ（P〈0.001）. Kaplan-Meier curves demonstrated that the survival rates for the three prognostic groups were significantly different according to final histology and ADC cut-offs （P〈0.001）. Conclusions： ADC is different according to local invasion, nodal involvement and the 7th TNM stage groups for GC, representing a potential, additional prognostic biomarker. The addition of DW-MRI could aid in the staging and risk stratification of GC.展开更多
Diffusion-weighted magnetic resonance imaging(DWMRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer.It has been proven valuable as a functional tool for qualita...Diffusion-weighted magnetic resonance imaging(DWMRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer.It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DWMRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the nonmono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging(DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.展开更多
AIM: To evaluate the accuracy of diffusion-weighted imaging(DWI) without bowel preparation,the optimal b value and the changes in apparent diffusion coefficient(ADC) in detecting ulcerative colitis(UC).METHODS: A tota...AIM: To evaluate the accuracy of diffusion-weighted imaging(DWI) without bowel preparation,the optimal b value and the changes in apparent diffusion coefficient(ADC) in detecting ulcerative colitis(UC).METHODS: A total of 20 patients who underwent 3T magnetic resonance imaging(MRI) without bowel preparation and colonoscopy within 24 h were recruited.Biochemical indexes,including C-reactive protein(CRP),erythrocyte sedimentation rate,hemoglobin,leucocytes,platelets,serum iron and albumin,were determined.Biochemical examinations were then performed within 24 h before or after MR colonography was conducted.DWI was performed at various b values(b = 0,400,600,800,and 1000 s/mm2).Two radiologists independently and blindly reviewed conventional- and contrast-enhanced MR images,DWI and ADC maps; these radiologists also determined ADC in each intestinal segment(rectum,sigmoid,left colon,transverse colon,and right colon).Receiver operating characteristic(ROC) analysis was performed to assess the diagnostic performance of DWI hyperintensity from various b factors,ADC values and different radiological signs to detect endoscopic inflammation in the corresponding bowel segment.Optimal ADC threshold was estimated by maximizing the combination of sensitivity and specificity.MRfindings were correlated with endoscopic results and clinical markers; these findings were then estimated by ROC analysis.RESULTS: A total of 100 segments(71 with endoscopic colonic inflammation; 29 normal) were included.The proposed total magnetic resonance score(MR-score-T) was correlated with the total modified Baron score(Baron-T; r = 0.875,P < 0.0001); the segmental MR score(MR-score-S) was correlated with the segmental modified Baron score(Baron-S; r = 0.761,P < 0.0001).MR-score-T was correlated with clinical and biological markers of disease activity(r = 0.445 to 0.831,P < 0.05).MR-score-S > 1 corresponded to endoscopic colonic inflammation with a sensitivity of 85.9%,a specificity of 82.8% and an area under the curve(AUC) of 0.929(P < 0.0001).The accuracy of DWI hyperintensity was significantly greater at b = 800 than at b = 400,600,or 1000 s/mm2(P < 0.05) when endoscopic colonic inflammation was detected.DWI hyperintensity at b = 800 s/mm2 indicated endoscopic colonic inflammation with a sensitivity of 93.0%,a specificity of 79.3% and an AUC of 0.867(P < 0.0001).Quantitative analysis results revealed that ADC values at b = 800 s/mm2 differed significantly between endoscopic inflamed segment and normal intestinal segment(1.56 ± 0.58 mm2/s vs 2.63 ± 0.46 mm2/s,P < 0.001).The AUC of ADC values was 0.932(95% confidence interval: 0.881-0.983) when endoscopic inflammation was detected.The threshold ADC value of 2.18 × 10-3 mm2/s indicated that endoscopic inflammation differed from normal intestinal segment with a sensitivity of 89.7% and a specificity of 80.3%.CONCLUSION: DWI combined with conventional MRI without bowel preparation provides a quantitative strategy to differentiate actively inflamed intestinal segments from the normal mucosa to detect UC.展开更多
There have been numerous studies done to explore the diagnostic performance of quanti- tative diffusion-weighted （DW） MR imaging to differentiate between benign and malignant pancre- atic masses. However, the result...There have been numerous studies done to explore the diagnostic performance of quanti- tative diffusion-weighted （DW） MR imaging to differentiate between benign and malignant pancre- atic masses. However, the results have been inconsistent. We performed a meta-analysis to investigate whether DW-MR imaging can differentiate between these two diseases. Databases including MEDLINE, EMBASE and Cochrane Library were utilized to find relevant articles published between January 2001 and January 2014. A Stata version 12.0 and a Meta-Disc version 1.4 were used to de- scribe primary results. Twelve studies with 594 patients, which fulfilled the inclusion criteria, were enrolled for the analysis. The pooled sensitivity and specificity of DW imaging was 0.91 （95% CI： 0.84, 0.95） and 0.86 （95% CI： 0.76, 0.93） respectively. The area under the curve of the summary re- ceiver operating characteristic was 0.95 （95% CI： 0.93, 0.96）. The results indicated that DW imaging might be a valuable tool for differentiating benign and malignant pancreatic masses.展开更多
BACKGROUND The activity staging of Crohn’s disease(CD)in the terminal ileum is critical in developing an accurate clinical treatment plan.The activity of terminal ileum CD is associated with the microcirculation of i...BACKGROUND The activity staging of Crohn’s disease(CD)in the terminal ileum is critical in developing an accurate clinical treatment plan.The activity of terminal ileum CD is associated with the microcirculation of involved bowel walls.Dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)and diffusionweighted imaging(DWI)can reflect perfusion and permeability of bowel walls by providing microcirculation information.As such,we hypothesize that DCE-MRI and DWI parameters can assess terminal ileum CD,thereby providing an opportunity to stage CD activity.AIM To evaluate the value of DCE-MRI and DWI in assessing activity of terminal ileum CD.METHODS Forty-eight patients with CD who underwent DCE-MRI and DWI were enrolled.The patients’activity was graded as remission,mild and moderate-severe.The transfer constant(Ktrans),wash-out constant(Kep),and extravascular extracellular volume fraction(Ve)were calculated from DCE-MRI and the apparent diffusion coefficient(ADC)was obtained from DWI.Magnetic Resonance Index of Activity(MaRIA)was calculated from magnetic resonance enterography.Differences in these quantitative parameters were compared between normal ileal loop(NIL)and inflamed terminal ileum(ITI)and among different activity grades.The correlations between these parameters,MaRIA,the Crohn’s Disease Activity Index(CDAI),and Crohn’s Disease Endoscopic Index of Severity(CDEIS)were examined.Receiver operating characteristic curve analyses were used to determine the diagnostic performance of these parameters in differentiating between CD activity levels.RESULTS Higher Ktrans(0.07±0.04 vs 0.01±0.01),Kep(0.24±0.11 vs 0.15±0.05)and Ve(0.27±0.07 vs 0.08±0.03),but lower ADC(1.41±0.26 vs 2.41±0.30)values were found in ITI than in NIL(all P<0.001).The Ktrans,Kep,Ve and MaRIA increased with disease activity,whereas the ADC decreased(all P<0.001).The Ktrans,Kep,Ve and MaRIA showed positive correlations with the CDAI(r=0.866 for Ktrans,0.870 for Kep,0.858 for Ve,0.890 for MaRIA,all P<0.001)and CDEIS(r=0.563 for Ktrans,0.567 for Kep,0.571 for Ve,0.842 for MaRIA,all P<0.001),while the ADC showed negative correlations with the CDAI(r=-0.857,P<0.001)and CDEIS(r=-0.536,P<0.001).The areas under the curve(AUC)for the Ktrans,Kep,Ve,ADC and MaRIA values ranged from 0.68 to 0.91 for differentiating inactive CD(CD remission)from active CD(mild to severe CD).The AUC when combining the Ktrans,Kep and Ve was 0.80,while combining DCE-MRI parameters and ADC values yielded the highest AUC of 0.95.CONCLUSION DCE-MRI and DWI parameters all serve as measures to stage CD activity.When they are combined,the assessment performance is improved and better than MaRIA.展开更多
基金the Cuiying Scientific and Technological Innovation Program of Lanzhou University Second Hospital,NO.CY2021-QNB09the Science and Technology Project of Gansu Province,NO.21JR11RA122+1 种基金Department of Education of Gansu Province:Innovation Fund Project,NO.2022B-056Gansu Province Clinical Research Center for Functional and Molecular Imaging,NO.21JR7RA438.
文摘BACKGROUND Diffusion-weighted imaging(DWI)has been developed to stage liver fibrosis.However,its diagnostic performance is inconsistent among studies.Therefore,it is worth studying the diagnostic value of various diffusion models for liver fibrosis in one cohort.AIM To evaluate the clinical potential of six diffusion-weighted models in liver fibrosis staging and compare their diagnostic performances.METHODS This prospective study enrolled 59 patients suspected of liver disease and scheduled for liver biopsy and 17 healthy participants.All participants underwent multi-b value DWI.The main DWI-derived parameters included Mono-apparent diffusion coefficient(ADC)from mono-exponential DWI,intravoxel incoherent motion model-derived true diffusion coefficient(IVIM-D),diffusion kurtosis imaging-derived apparent diffusivity(DKI-MD),stretched exponential model-derived distributed diffusion coefficient(SEM-DDC),fractional order calculus(FROC)model-derived diffusion coefficient(FROC-D)and FROC model-derived microstructural quantity(FROC-μ),and continuous-time random-walk(CTRW)model-derived anomalous diffusion coefficient(CTRW-D)and CTRW model-derived temporal diffusion heterogeneity index(CTRW-α).The correlations between DWI-derived parameters and fibrosis stages and the parameters’diagnostic efficacy in detecting significant fibrosis(SF)were assessed and compared.RESULTS CTRW-D(r=-0.356),CTRW-α(r=-0.297),DKI-MD(r=-0.297),FROC-D(r=-0.350),FROC-μ(r=-0.321),IVIM-D(r=-0.251),Mono-ADC(r=-0.362),and SEM-DDC(r=-0.263)were significantly correlated with fibrosis stages.The areas under the ROC curves(AUCs)of the combined index of the six models for distinguishing SF(0.697-0.747)were higher than each of the parameters alone(0.524-0.719).The DWI models’ability to detect SF was similar.The combined index of CTRW model parameters had the highest AUC(0.747).CONCLUSION The DWI models were similarly valuable in distinguishing SF in patients with liver disease.The combined index of CTRW parameters had the highest AUC.
基金Egyptian Ministry for Scientific Research,Science,Technology&Innovation Funding Authority(STDF),No.HCV-3506.
文摘BACKGROUND Chronic hepatitis C(CHC)is a health burden with consequent morbidity and mortality.Liver biopsy is the gold standard for evaluating fibrosis and assessing disease severity and prognostic purposes post-treatment.Noninvasive altern-atives for liver biopsy such as transient elastography(TE)and diffusion-weighted magnetic resonance imaging(DW-MRI)are critical needs.AIM To evaluate TE and DW-MRI as noninvasive tools for predicting liver fibrosis in children with CHC.METHODS This prospective cross-sectional study initially recruited 100 children with CHC virus infection.Sixty-four children completed the full set of investigations including liver stiffness measurement(LSM)using TE and measurement of apparent diffusion coefficient(ADC)of the liver and spleen using DW-MRI.Liver biopsies were evaluated for fibrosis using Ishak scoring system.LSM and liver and spleen ADC were compared in different fibrosis stages and correlation analysis was performed with histopathological findings and other laboratory parameters.RESULTS Most patients had moderate fibrosis(73.5%)while 26.5%had mild fibrosis.None had severe fibrosis or cirrhosis.The majority(68.8%)had mild activity,while only 7.8%had moderate activity.Ishak scores had a significant direct correlation with LSM(P=0.008)and were negatively correlated with both liver and spleen ADC but with no statistical significance(P=0.086 and P=0.145,respectively).Similarly,histopatho-logical activity correlated significantly with LSM(P=0.002)but not with liver or spleen ADC(P=0.84 and 0.98 respectively).LSM and liver ADC were able to significantly discriminate F3 from lower fibrosis stages(area under the curve=0.700 and 0.747,respectively)with a better performance of liver ADC.CONCLUSION TE and liver ADC were helpful in predicting significant fibrosis in children with chronic hepatitis C virus infection with a better performance of liver ADC.
文摘Objective： The aim of our study was to analysis the pictures of conventional magnetic resonance imaging （MR）, diffusion-weighted imaging （DWl） and dynamic enhanced magnetic resonance imaging （DEMRI） of pancreatic endocrine tumors （PETs）, and evaluate diagnostic value of MR, DWl and DEMRI for diagnosing PETs. Methods： DWl and DEMRI scanning toward 13 patients with PETs being confirmed by surgical pathology before surgery on the basis of conventional MR scanning were carried out, and MR findings was analyzed retrospectively. Results： Of 13 patients with PETs there was 11 cases with single lesion, 2 with multiple, and had 15 lesions altogether, of which there were 3 lesions in pancreatic head, 1 in its neck, 2 in its body, 4 in its body and tail, 5 in its tail. MR findings： （1） T1WI signal was low or slightly lower （9/15）, and equal ones （5/15）; （2） T2WI showed high or slightly higher signal （10/15）, and equal ones （5/15）; （3） T1WI with fat suppression： the signal was low （11/15）, mixed signal （2/15）, and equal ones （2/15）; （4） DWI： normal pancreatic tissue exhibited homogeneous intermediate signal, all 15 lesions were high or slightly higher signal, the measured ADC values of tissue of PETs was （1.124 ± 0.252） × 104 mm2/s, and the ADC value of normal pancreatic tissue （1.873 ± 0.157） × 10^3 mm2/s; （5） Enhanced （M3D/LAVA） scanning： among 13 patients with PETs there were 12 pancreatic lesions with significantly enhanced signals in the arterial phase in all 15, and significantly higher than normal pancreatic tissue, and two slight enhancement was slightly higher signal; and 1 no enhancement. Enhanced pattern： homogeneous enhancement were 6 lesions, and the heterogeneous 4, and the edge ring 5. Conclusion： MR and DWl combining with DEMRI help qualitative diagnosis of pancreatic endocrine tumors.
基金supported by a grant from the Health Research New Zealand(HRC)22/559(to AJG and LB)。
文摘Moderate to severe perinatal hypoxic-ischemic encephalopathy occurs in~1 to 3/1000 live births in high-income countries and is associated with a significant risk of death or neurodevelopmental disability.Detailed assessment is important to help identify highrisk infants,to help families,and to support appropriate interventions.A wide range of monitoring tools is available to assess changes over time,including urine and blood biomarkers,neurological examination,and electroencephalography.At present,magnetic resonance imaging is unique as although it is expensive and not suited to monitoring the early evolution of hypoxic-ischemic encephalopathy by a week of life it can provide direct insight into the anatomical changes in the brain after hypoxic-ischemic encephalopathy and so offers strong prognostic information on the long-term outcome after hypoxic-ischemic encephalopathy.This review investigated the temporal dynamics of neonatal hypoxic-ischemic encephalopathy injuries,with a particular emphasis on exploring the correlation between the prognostic implications of magnetic resonance imaging scans in the first week of life and their relationship to long-term outcome prediction,particularly for infants treated with therapeutic hypothermia.A comprehensive literature search,from 2016 to 2024,identified 20 pertinent articles.This review highlights that while the optimal timing of magnetic resonance imaging scans is not clear,overall,it suggests that magnetic resonance imaging within the first week of life provides strong prognostic accuracy.Many challenges limit the timing consistency,particularly the need for intensive care and clinical monitoring.Conversely,although most reports examined the prognostic value of scans taken between 4 and 10 days after birth,there is evidence from small numbers of cases that,at times,brain injury may continue to evolve for weeks after birth.This suggests that in the future it will be important to explore a wider range of times after hypoxic-ischemic encephalopathy to fully understand the optimal timing for predicting long-term outcomes.
文摘In this editorial,we comment on the article by Lambert et al,published in the recent issue of the World Journal of Radiology.The focus of the editorial is to explore the advancements in whole-body magnetic resonance imaging(WB-MRI)techno-logy,its current clinical applications,and the challenges that must be addressed to fully realize its potential in oncological imaging.WB-MRI has emerged as a pivotal tool in oncological imaging,offering comprehensive disease assessment without ionizing radiation.Its applications span the detection of bone metastases,evaluation of hematologic malignancies,and staging of a wide range of cancers,including lymphoma,prostate,and breast cancers.Advanced techniques such as diffusion-weighted imaging have enhanced its diagnostic performance by pro-viding superior lesion-to-background contrast and quantitative metrics.Despite its diagnostic strengths,WB-MRI faces challenges in standardization,patient acceptance,and integration into clinical workflows.Variability in acquisition pro-tocols,hardware differences,and patient-related factors,such as anxiety and motion artifacts,have limited widespread adoption.Emerging guidelines like MET-RADS-P and ONCO-RADS aim to address these issues by promoting stan-dardized protocols tailored to specific clinical needs.This editorial explores the advancements in WB-MRI technology,its current clinical applications,and the barriers that must be overcome to maximize its utility.By addressing these cha-llenges and embracing standardization,WB-MRI holds the potential to redefine the landscape of oncological imaging,aligning diagnostic precision with modern treatment goals of reducing long-term patient risk.
基金supported by the National Natural Science Foundation of China under Grant No.62075235,National Key R&D Program of China under Grant No.2021YFF0700700Gusu Innovation and Entrepreneurship Leading Talents in Suzhou City under Grant No.ZXL2021425+1 种基金Youth Innovation Promotion Association of the Chinese Academy of Sciences under Grant No.2019320Innovation of Scientific Research Strategic Priority Research Program of the Chinese Academy of Sciences under Grant No.XDA15021304.
文摘The parafoveal area,with its high concentration of photoreceptors andfine retinal capillaries,is crucial for central vision and often exhibits early signs of pathological changes.The current adaptive optics scanning laser ophthalmoscope(AOSLO)provides an excellent tool to acquire accurate and detailed information about the parafoveal area with cellular resolution.However,limited by the scanning speed of two-dimensional scanning,thefield of view(FOV)in the AOSLO system was usually less than or equal to 2,and the stitching for the parafoveal area required dozens of images,which was time-consuming and laborious.Unfortunately,almost half of patients are unable to obtain stitched images because of their poorfixation.To solve this problem,we integrate AO technology with the line-scan imaging method to build an adaptive optics line scanning ophthalmoscope(AOLSO)system with a larger FOV.In the AOLSO,afocal spherical mirrors in pairs are nonplanar arranged and the distance and angle between optical elements are optimized to minimize the aberrations,two cylinder lenses are orthogonally placed before the imaging sensor to stretch the point spread function(PSF)for sufficiently digitizing light energy.Captured human retinal images show the whole parafoveal area with 55FOV,60 Hz frame rate and cellular resolutions.Take advantage of the 5FOV of the AOLSO,only 9 frames of the retina are captured with several minutes to stitch a montage image with an FOV of 99,in which photoreceptor counting is performed within approximately 5eccentricity.The AOLSO system not only provides cellular resolution but also has the capability to capture the parafoveal region in a single frame,which offers great potential for noninvasive studying of the parafoveal area.
文摘AIM： To evaluate the utility of diffusion-weighted imaging （DWl） in screening and differential diagnosis of benign and malignant focal hepatic lesions. METHODS： Magnetic resonance imaging （MRI） examinations were performed using the Signa Excite Xl Twin Speed 1.5T system （GE Healthcare, Milwaukee, Wl, USA）. Seventy patients who had undergone MRI of the liver [29 hepatocellular carcinomas （HCC）, four cholangiocarcinomas, 34 metastatic liver cancers, 10 hemangiomas, and eight cysts] between April 2004 and August 2008 were retrospectively evaluated. Visualization of lesions, relative contrast ratio （RCR）, and apparent diffusion coefficient （ADC） were compared between benign and malignant lesions on DWl. Su- perparamagnetic iron oxide （SPIO） was administered to 59 patients, and RCR was compared pre- and postadministration.RESULTS： DWI showed higher contrast between malignant lesions （especially in multiple small metastatic cancers） and surrounding liver parenchyma than did contrast-enhanced computed tomography. ADCs （mean±SD × 10^-3 mm2/s） were significantly lower （P 〈 0.05） in malignant lesions （HCC： 1.31 ± 0.28 and liver metastasis： 1.11 ± 0.22） and were significantly higher in benign lesions （hemangioma： 1.84 ± 0.37 and cyst： 2.61 ± 0.45） than in the surrounding hepatic tissues. RCR between malignant lesions and surrounding he- patic tissues significantly improved after SPIO administration, but RCRs in benign lesions were not improved.CONCLUSION： DWI is a simple and sensitive method for screening focal hepatic lesions and is useful for differential diagnosis.
文摘Diffusion-weighted imaging (DWI) is an established diagnostic method of acute stroke. The latest advances in magnetic resonance imaging (MRI) technology have greatly expanded the utility of DWI in the examination of various organs. Recent studies have revealed the usefulness of DWI for imaging of the liver, kidney, ovary, and breast. We report a patient with acute pancreatitis detected by DWI and discussed the efficacy of DWI in diagnosing acute pancreatitis. A 50-year old man presented with a primary complaint of abdominal pain. We performed both DWI and computed tomography (CT) for this patient. The signal intensity in a series of DWI was measured and the apparent diffusion coefficient (ADC) values were calculated to differentiate inflammation from normal tissue. Two experienced radiologists evaluated the grade of acute pancreatitis by comparing the CT findings. Initially, the pancreas and multiple ascites around the pancreas produced a bright signal and ADC values were reduced on DWI. As the inflammation decreased, the bright signal faded to an iso-signal and the ADC values returned to their normal level. There was no difference in the abilities of DWI and CT images to detect acute pancreatitis. However, our case indicates that DWI can evaluate the manifestations of acute pancreatitis using no enhancement material andhas the potential to replace CT as a primary diagnostic strategy for acute pancreatitis.
基金National Natural Science Foundation of China,No.81471658Science and Technology Support Program of Sichuan Province,No.2017SZ0003
文摘BACKGROUND The Liver Imaging Reporting and Data System(LI-RADS), supported by the American College of Radiology(ACR), has been developed for standardizing the acquisition, interpretation, reporting, and data collection of liver imaging examinations in patients at risk for hepatocellular carcinoma(HCC). Diffusionweighted imaging(DWI), which is described as an ancillary imaging feature of LI-RADS, can improve the diagnostic efficiency of LI-RADS v2017 with gadoxetic acid-enhanced magnetic resonance imaging(MRI) for HCC.AIM To determine whether the use of DWI can improve the diagnostic efficiency of LIRADS v2017 with gadoxetic acid-enhanced magnetic resonance MRI for HCC.METHODS In this institutional review board-approved study, 245 observations of high risk of HCC were retrospectively acquired from 203 patients who underwent gadoxetic acid-enhanced MRI from October 2013 to April 2018. Two readers independently measured the maximum diameter and recorded the presence of each lesion and assigned scores according to LI-RADS v2017. The test was used to determine the agreement between the two readers with or without DWI. In addition, the sensitivity(SE), specificity(SP), accuracy(AC), positive predictive value(PPV), and negative predictive value(NPV) of LI-RADS were calculated.Youden index values were used to compare the diagnostic performance of LIRADS with or without DWI.RESULTS Almost perfect interobserver agreement was obtained for the categorization of observations with LI-RADS(kappa value: 0.813 without DWI and 0.882 with DWI). For LR-5, the diagnostic SE, SP, and AC values were 61.2%, 92.5%, and71.4%, respectively, with or without DWI; for LR-4/5, they were 73.9%, 80%, and75.9% without DWI and 87.9%, 80%, and 85.3% with DWI; for LR-4/5/M, they were 75.8%, 58.8%, and 70.2% without DWI and 87.9%, 58.8%, and 78.4% with DWI; for LR-4/5/TIV, they were 75.8%, 75%, and 75.5% without DWI and 89.7%,75%, and 84.9% with DWI. The Youden index values of the LI-RADS classification without or with DWI were as follows: LR-4/5: 0.539 vs 0.679; LR-4/5/M: 0.346 vs 0.467; and LR-4/5/TIV: 0.508 vs 0.647.CONCLUSION LI-RADS v2017 has been successfully applied with gadoxetate-enhanced MRI for patients at high risk for HCC. The addition of DWI significantly increases the diagnostic efficiency for HCC.
基金the National Natural Science Foundation of China, No. 30070235, 30470508
文摘AIM: To investigate dynamic characteristics and pathological mechanism of signal in rabbit VX-2 tumor model on diffusion-weighted imaging (DWI) after chemoembolization. METHODS: Forty New Zealand rabbits were included in the study and forty-seven rabbit VX-2 tumor models were raised by implanting directly and intrahepatically after abdominal cavity opened. Forty VX-2 tumor models from them were divided into four groups. DWI was performed periodically and respectively for each group after chemoembolization. All VX-2 tumor samples of each group were studied by pathology. The distinction of VX-2 tumors on DWI was assessed by their apparent diffusion coefficient (ADC) values. The statistical significance between different time groups, different area groups or different b-value groups was calculated by using SPSS12.0 software. RESULTS: Under b-value of 100 s/mm2, ADC values were lowest at 16 h after chemoembolization in area of VX-2 tumor periphery, central, and normal liver parenchyma around tumor, but turned to increase with further elongation of chemoembolization treatment. The distinction of ADC between different time groups was significant respectively (F = 7.325, P < 0.001; F = 2.496, P < 0.048; F = 6.856, P < 0.001). Cellular edema in the area of VX-2 tumor periphery or normal liver parenchyma around tumor, increased quickly in sixteen h after chemoembolization but, from the 16th h to the 48th h, cellular edema in the area of normal liver parenchyma around tumor decreased gradually and that in the area of VX-2 tumor periphery decreased lightly at, and then increased continually. After chemoembolization, Cellular necrosis in the area of VX-2 tumor periphery was more significantly high than that before chemoembolization. The areas of dead cells in VX-2 tumors manifested low signal and high ADC value, while the areas of viable cells manifested high signal and low ADC value. CONCLUSION: DWI is able to detect and differentiate tumor necrotic areas from viable cellular areas before and after chemoembolization. ADC of normal liver parenchyma and VX-2 tumor are influenced by intracellular edema, tissue cellular death and microcirculation disturbance after chemoembolization.
基金Supported by National Institutes of Health R01 CA126809
文摘AIM: To investigate whether intra-procedural diffusion- weighted magnetic resonance imaging can predict response of hepatocellular carcinoma (HCC) during trans- catheter arterial chemoembolization (TACE). METHODS: Sixteen patients (15 male), aged 59 ±11 years (range: 42-81 years) underwent a total of 21 separate treatments for unresectable HCC in a hybrid magnetic resonance/interventional radiology suite. Ana- tomical imaging and diffusion-weighted imaging (b = 0, 500 s/mm2) were performed on a 1.5-T unit. Tumor enhancement and apparent diffusion coefficient (ADC, mm2/s) values were assessed immediately before and at 1 and 3 mo after TACE. We calculated the percent change (PC) in ADC values at all time points. We compared follow-up ADC values to baseline values using a paired t test (α = 0.05). RESULTS: The intra-procedural sensitivity, specificity, and positive and negative predictive values (%) for detecting a complete or partial 1-mo tumor response using ADC PC thresholds of ±5%, ±10%, and ±15% were 77, 67, 91, and 40; 54, 67, 88, and 25; and 46, 100, 100, and 30, respectively. There was no clear predictive value for the 3-mo follow-up. Compared to baseline, the immediate post-procedure and 1-mo mean ADC values both increased; the latter obtaining statistical significance (1.48 ± 0.29 mm2/s vs 1.65 ± 0.35 × 10-3 mm2/s, P < 0.014). CONCLUSION: Intra-procedural ADC changes of > 15% predicted 1-mo anatomical HCC response with the greatest accuracy, and can provide valuable feedback at the time of TACE.
基金Supported by Clinical research grant from Pusan National University Hospital
文摘Diffusion-weighted magnetic resonance imaging(DWI)is a well established method for the evaluation of intracranial diseases,such as acute stroke.DWI for extracranial application is more difficult due to physiological motion artifacts and the heterogeneous composition of the organs.However,thanks to the newer technical development of DWI,DWI has become increasingly used over the past few years in extracranial organs including the abdomen and pelvis.Most previous studies of DWI have been limited to the evaluation of diffuse parenchymal abnormalities and focal lesions in abdominal organs,whereas there are few studies about DWI for the evaluation of the biliopancreatic tract.Although further studies are needed to determine its performance in evaluating bile duct,gallbladder and pancreas diseases,DWI has potential in the assessment of the functional information on the biliopancreatic tract concerning the status of tissue cellularity,because increased cellularity is associated with impeded diffusion,as indicated by a reduction in the apparent diffusion coefficient.The detection of malignant lesions and their differentiation from benign tumor-like lesions in the biliopancreatic tract could be improved using DWI in conjunction with findings obtained with conventional magnetic resonance cholagiopancreatography.Additionally,DWI can be useful for the assessment of the biliopancreatic tract in patients with renal impairment because contrast-enhanced computed tomography or magnetic resonance scans should be avoided in these patients.
文摘AIM:To evaluate the clinical value of diffusion-weighted magnetic resonance imaging(DW-MRI)in predicting the response of rectal cancer to neoadjuvant chemoradiation.METHODS:This prospective study was approved by our institutional review board,and informed consent was obtained from each patient.Fifteen patients(median age 56 years)with locally advanced rectal cancer were treated in our hospital from June 2006 to December 2007.All patients were stageⅢB-C according to the results of MRI and endorectal ultrasound examinations.All patients underwent pelvic irradiation with 45 Gy/25 fx per 35 days.The concurrent chemotherapy regimen consisted of capecitabine 625mg/m2,bid(Monday-Friday),and oxaliplatin 50 mg/m2,weekly.The patients underwent surgery 5-8 wk after the completion of neoadjuvant therapy.T downstaging was defined as the downstaging of the tumor from cT3to ypT0-2 or from cT4 to ypT0-3.Good regression was defined as TRG 3-4,and poor regression was defined as TRG 0-2.Diffusion-weighted magnetic resonance images were obtained prior to and weekly during the course of neoadjuvant chemoradiation,and the apparent diffusion coefficient(ADC)values were calculated from the acquired tumor images.RESULTS:Comparison with the mean pretreatment tumor ADC revealed an increase in the mean tumor ADC during the course of neoadjuvant chemoradiation,especially at the 2ndweek(P=0.004).We found a strong negative correlation between the mean pretreatment tumor ADC and tumor regression after neoadjuvant chemoradiation(P=0.021).In the T downstage and tumor regression groups,we found a significant increase in the mean ADC at the 2ndweek of neoadjuvant therapy(P=0.011;0.004).CONCLUSION:DW-MRI might be a valuable clinical tool to help predict or assess the response of rectal cancer to neoadjuvant chemoradiation at an early timepoint.
文摘Diffusion-weighted imaging (DWI) is one of the magnetic resonance imaging (MRI) sequences providing qualitative as well as quantitative information at a cellular level. It has been widely used for various applications in the central nervous system. Over the past decade, various extracranial applications of DWI have been increasingly explored, as it may detect changes even before signal alterations or morphological abnormalities become apparent on other pulse sequences. Initial results from abdominal MRI applications are promising, particularly in oncological settings and for the detection of abscesses. The purpose of this article is to describe the clinically relevant basic concepts of DWI, techniques to perform abdominal DWI, its analysis and applications in abdominal visceral MR imaging, in addition to a brief overview of whole body DWI MRI.
文摘Objective： To investigate the role of apparent diffusion coefficient （ADC） from diffusion-weighted magnetic resonance imaging （DW-MRI） when applied to the 7th TNM classification in the staging and prognosis of gastric cancer （GC）. Methods： Between October 2009 and May 2014, a total of 89 patients with non-metastatic, biopsy proven GC underwent 1.5T DW-MRI, and then treated with radical surgery. Tumor ADC was measured retrospectively and compared with final histology following the 7th TNM staging （local invasion, nodal involvement and according to the different groups -- stage Ⅰ, Ⅱ and Ⅲ）. Kaplan-Meier curves were also generated. The follow-up period is updated to May 2016. Results： Median follow-up period was 33 months and 45/89 （51%） deaths from GC were observed. ADC was significantly different both for local invasion and nodal involvement （P〈0.001）. Considering final histology as the reference standard, a preoperative ADC cut-offof 1.80×10-3 mm^2/s could distinguish between stages I and Ⅱ and an ADC value of ≤1.36-10-3 mm^2/s was associated with stage Ⅲ（P〈0.001）. Kaplan-Meier curves demonstrated that the survival rates for the three prognostic groups were significantly different according to final histology and ADC cut-offs （P〈0.001）. Conclusions： ADC is different according to local invasion, nodal involvement and the 7th TNM stage groups for GC, representing a potential, additional prognostic biomarker. The addition of DW-MRI could aid in the staging and risk stratification of GC.
文摘Diffusion-weighted magnetic resonance imaging(DWMRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer.It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DWMRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the nonmono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging(DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.
文摘AIM: To evaluate the accuracy of diffusion-weighted imaging(DWI) without bowel preparation,the optimal b value and the changes in apparent diffusion coefficient(ADC) in detecting ulcerative colitis(UC).METHODS: A total of 20 patients who underwent 3T magnetic resonance imaging(MRI) without bowel preparation and colonoscopy within 24 h were recruited.Biochemical indexes,including C-reactive protein(CRP),erythrocyte sedimentation rate,hemoglobin,leucocytes,platelets,serum iron and albumin,were determined.Biochemical examinations were then performed within 24 h before or after MR colonography was conducted.DWI was performed at various b values(b = 0,400,600,800,and 1000 s/mm2).Two radiologists independently and blindly reviewed conventional- and contrast-enhanced MR images,DWI and ADC maps; these radiologists also determined ADC in each intestinal segment(rectum,sigmoid,left colon,transverse colon,and right colon).Receiver operating characteristic(ROC) analysis was performed to assess the diagnostic performance of DWI hyperintensity from various b factors,ADC values and different radiological signs to detect endoscopic inflammation in the corresponding bowel segment.Optimal ADC threshold was estimated by maximizing the combination of sensitivity and specificity.MRfindings were correlated with endoscopic results and clinical markers; these findings were then estimated by ROC analysis.RESULTS: A total of 100 segments(71 with endoscopic colonic inflammation; 29 normal) were included.The proposed total magnetic resonance score(MR-score-T) was correlated with the total modified Baron score(Baron-T; r = 0.875,P < 0.0001); the segmental MR score(MR-score-S) was correlated with the segmental modified Baron score(Baron-S; r = 0.761,P < 0.0001).MR-score-T was correlated with clinical and biological markers of disease activity(r = 0.445 to 0.831,P < 0.05).MR-score-S > 1 corresponded to endoscopic colonic inflammation with a sensitivity of 85.9%,a specificity of 82.8% and an area under the curve(AUC) of 0.929(P < 0.0001).The accuracy of DWI hyperintensity was significantly greater at b = 800 than at b = 400,600,or 1000 s/mm2(P < 0.05) when endoscopic colonic inflammation was detected.DWI hyperintensity at b = 800 s/mm2 indicated endoscopic colonic inflammation with a sensitivity of 93.0%,a specificity of 79.3% and an AUC of 0.867(P < 0.0001).Quantitative analysis results revealed that ADC values at b = 800 s/mm2 differed significantly between endoscopic inflamed segment and normal intestinal segment(1.56 ± 0.58 mm2/s vs 2.63 ± 0.46 mm2/s,P < 0.001).The AUC of ADC values was 0.932(95% confidence interval: 0.881-0.983) when endoscopic inflammation was detected.The threshold ADC value of 2.18 × 10-3 mm2/s indicated that endoscopic inflammation differed from normal intestinal segment with a sensitivity of 89.7% and a specificity of 80.3%.CONCLUSION: DWI combined with conventional MRI without bowel preparation provides a quantitative strategy to differentiate actively inflamed intestinal segments from the normal mucosa to detect UC.
基金supported by the Science Foundation for Distinguished Young Scholars of Sichuan Province,China(No.2012JQ0060)
文摘There have been numerous studies done to explore the diagnostic performance of quanti- tative diffusion-weighted （DW） MR imaging to differentiate between benign and malignant pancre- atic masses. However, the results have been inconsistent. We performed a meta-analysis to investigate whether DW-MR imaging can differentiate between these two diseases. Databases including MEDLINE, EMBASE and Cochrane Library were utilized to find relevant articles published between January 2001 and January 2014. A Stata version 12.0 and a Meta-Disc version 1.4 were used to de- scribe primary results. Twelve studies with 594 patients, which fulfilled the inclusion criteria, were enrolled for the analysis. The pooled sensitivity and specificity of DW imaging was 0.91 （95% CI： 0.84, 0.95） and 0.86 （95% CI： 0.76, 0.93） respectively. The area under the curve of the summary re- ceiver operating characteristic was 0.95 （95% CI： 0.93, 0.96）. The results indicated that DW imaging might be a valuable tool for differentiating benign and malignant pancreatic masses.
基金Medical Innovation Program of Fujian Province,No.2018-CX-30Startup Fund for Scientific Research of Fujian Medical University,No.2018QH1054.
文摘BACKGROUND The activity staging of Crohn’s disease(CD)in the terminal ileum is critical in developing an accurate clinical treatment plan.The activity of terminal ileum CD is associated with the microcirculation of involved bowel walls.Dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)and diffusionweighted imaging(DWI)can reflect perfusion and permeability of bowel walls by providing microcirculation information.As such,we hypothesize that DCE-MRI and DWI parameters can assess terminal ileum CD,thereby providing an opportunity to stage CD activity.AIM To evaluate the value of DCE-MRI and DWI in assessing activity of terminal ileum CD.METHODS Forty-eight patients with CD who underwent DCE-MRI and DWI were enrolled.The patients’activity was graded as remission,mild and moderate-severe.The transfer constant(Ktrans),wash-out constant(Kep),and extravascular extracellular volume fraction(Ve)were calculated from DCE-MRI and the apparent diffusion coefficient(ADC)was obtained from DWI.Magnetic Resonance Index of Activity(MaRIA)was calculated from magnetic resonance enterography.Differences in these quantitative parameters were compared between normal ileal loop(NIL)and inflamed terminal ileum(ITI)and among different activity grades.The correlations between these parameters,MaRIA,the Crohn’s Disease Activity Index(CDAI),and Crohn’s Disease Endoscopic Index of Severity(CDEIS)were examined.Receiver operating characteristic curve analyses were used to determine the diagnostic performance of these parameters in differentiating between CD activity levels.RESULTS Higher Ktrans(0.07±0.04 vs 0.01±0.01),Kep(0.24±0.11 vs 0.15±0.05)and Ve(0.27±0.07 vs 0.08±0.03),but lower ADC(1.41±0.26 vs 2.41±0.30)values were found in ITI than in NIL(all P<0.001).The Ktrans,Kep,Ve and MaRIA increased with disease activity,whereas the ADC decreased(all P<0.001).The Ktrans,Kep,Ve and MaRIA showed positive correlations with the CDAI(r=0.866 for Ktrans,0.870 for Kep,0.858 for Ve,0.890 for MaRIA,all P<0.001)and CDEIS(r=0.563 for Ktrans,0.567 for Kep,0.571 for Ve,0.842 for MaRIA,all P<0.001),while the ADC showed negative correlations with the CDAI(r=-0.857,P<0.001)and CDEIS(r=-0.536,P<0.001).The areas under the curve(AUC)for the Ktrans,Kep,Ve,ADC and MaRIA values ranged from 0.68 to 0.91 for differentiating inactive CD(CD remission)from active CD(mild to severe CD).The AUC when combining the Ktrans,Kep and Ve was 0.80,while combining DCE-MRI parameters and ADC values yielded the highest AUC of 0.95.CONCLUSION DCE-MRI and DWI parameters all serve as measures to stage CD activity.When they are combined,the assessment performance is improved and better than MaRIA.
