In x-ray dark-field imaging using dual phase grating interferometer,multi-contrast signals are extracted from a set of acquired phase-stepping data by using the least-squares fitting algorithm.The extracted mean inten...In x-ray dark-field imaging using dual phase grating interferometer,multi-contrast signals are extracted from a set of acquired phase-stepping data by using the least-squares fitting algorithm.The extracted mean intensity,amplitude and visibility signals may be intrinsically biased.However,it is still unclear how large these biases are and how the data acquisition parameters influence the biases in the extracted signals.This work set out to address these questions.Analytical expressions of the biases of the extracted signals were theoretically derived by using a second-order Taylor series expansion.Extensive numerical simulations were performed to validate the theoretical results.It is illustrated that while the estimated mean intensity signal is always unbiased,the estimated amplitude and visibility signals are both positively biased.While the biases of the estimated amplitude signals are proportional to the inverse of the total number of phase steps,the biases of the estimated visibility signals are inversely proportional to the product of the total number of phase steps and the mean number of photons counted per phase step.Meanwhile,it is demonstrated that the dependence of the biases on the mean visibility is quite different from that of Talbot-Lau interferometer due to the difference in the intensity model.We expect that these results can be useful for data acquisition optimizations and interpretation of x-ray dark-field images.展开更多
BACKGROUND Pneumoparotid is a rare disease associated with retrograde airflow into the ductal system.There is no established treatment for this disease,which has no known complications.Mouth puffing and playing wind i...BACKGROUND Pneumoparotid is a rare disease associated with retrograde airflow into the ductal system.There is no established treatment for this disease,which has no known complications.Mouth puffing and playing wind instruments are known to be the causes of this disease.CASE SUMMARY We managed a case,in which pneumoparotid suddenly recurred 4 months after surgery for purulent parotiditis.The patient did not report any obvious etiological factors,such as mouth puffing or playing a wind instrument.We reviewed 128 articles(from 1941 to 2023)that reported on a total of 166 patients with pneumoparotid,including the patient from the present case report,with imaging findings.This is the first reported case of pneumoparotid following surgery for purulent parotitis.The etiology in our case was classified as idiopathic.CONCLUSION Imaging findings could be sufficient for accurate pneumoparotid diagnoses and the exclusion of complications;computed tomography could be useful.展开更多
Scintillation semiconductors play increasingly important medical diagnosis and industrial inspection roles.Recently,two-dimensional(2D)perovskites have been shown to be promising materials for medical X-ray imaging,bu...Scintillation semiconductors play increasingly important medical diagnosis and industrial inspection roles.Recently,two-dimensional(2D)perovskites have been shown to be promising materials for medical X-ray imaging,but they are mostly used in low-energy(≤130 keV)regions.Direct detection of MeV X-rays,which ensure thorough penetration of the thick shell walls of containers,trucks,and aircraft,is also highly desired in practical industrial applications.Unfortunately,scintillation semiconductors for high-energy X-ray detection are currently scarce.Here,This paper reports a 2D(C_(4)H_(9)NH_(3))_(2)PbBr_(4)single crystal with outstanding sensitivity and stability toward X-ray radiation that provides an ultra-wide detectable X-ray range of between 8.20 nGy_(air)s^(-1)(50 keV)and 15.24 mGy_(air)s^(-1)(9 MeV).The(C_(4)H_(9)NH_(3))_(2)PbBr_(4)single-crystal detector with a vertical structure is used for high-performance X-ray imaging,delivering a good spatial resolution of 4.3 Ip mm^(-1)in a plane-scan imaging system.Low ionic migration in the 2D perovskite enables the vertical device to be operated with hundreds of keV to MeV X-ray radiation at high bias voltages,leading to a sensitivity of 46.90μC Gy_(air)-1 cm^(-2)(-1.16 Vμm^(-1))with 9 MeV X-ray radiation,demonstrating that 2D perovskites have enormous potential for high-energy industrial applications.展开更多
Angiomyolipomas(AMLs)represent the most common benign solid renal tumors.The frequency of their detection in the general population is increasing owing to advances in imaging technology.The objective of this review is...Angiomyolipomas(AMLs)represent the most common benign solid renal tumors.The frequency of their detection in the general population is increasing owing to advances in imaging technology.The objective of this review is to discuss computed tomography(CT)and magnetic resonance imaging findings for both typical and atypical renal AMLs,along with their associated complications.AMLs are typically defined as solid triphasic tumors composed of varying amounts of dysmorphic and tortuous blood vessels,smooth muscle components and adipose tissue.In an adult,a classical renal AML appears as a solid,heterogeneous renal cortical mass with macroscopic fat.However,up to 5%of AMLs contain minimal fat and cannot be reliably diagnosed by imaging.Fat-poor AMLs can appear as hyperattenuating masses on unenhanced CT and as hypointense masses on T2WI;other AMLs may be isodense or exhibit cystic components.Hemorrhage is the most common complication,and AMLs with hemorrhage can mimic other tumors,making their diagnosis challenging.Understanding the variable and heterogeneous nature of this neoplasm to correctly classify renal AMLs and to avoid misdiagnosis of other renal lesions is crucial.展开更多
The parasitic hydrogen evolution reaction(HER)in the negative half-cell of vanadium redox flow batteries(VRFBs)causes severe efficiency losses.Thus,a deeper understanding of this process and the accompanying bubble fo...The parasitic hydrogen evolution reaction(HER)in the negative half-cell of vanadium redox flow batteries(VRFBs)causes severe efficiency losses.Thus,a deeper understanding of this process and the accompanying bubble formation is crucial.This benchmarking study locally analyzes the bubble distribution in thick,porous electrodes for the first time using deep learning-based image segmentation of synchrotron X-ray micro-tomograms.Each large three-dimensional data set was processed precisely in less than one minute while minimizing human errors and pointing out areas of increased HER activity in VRFBs.The study systematically varies the electrode potential and material,concluding that more negative electrode potentials of-200 m V vs.reversible hydrogen electrode(RHE)and lower cause more substantial bubble formation,resulting in bubble fractions of around 15%–20%in carbon felt electrodes.Contrarily,the bubble fractions stay only around 2%in an electrode combining carbon felt and carbon paper.The detected areas with high HER activity,such as the border subregion with more than 30%bubble fraction in carbon felt electrodes,the cutting edges,and preferential spots in the electrode bulk,are potential-independent and suggest that larger electrodes with a higher bulk-to-border ratio might reduce HER-related performance losses.The described combination of electrochemical measurements,local X-ray microtomography,AI-based segmentation,and 3D morphometric analysis is a powerful and novel approach for local bubble analysis in three-dimensional porous electrodes,providing an essential toolkit for a broad community working on bubble-generating electrochemical systems.展开更多
Background: When applied to trabecular bone X-ray images, the anisotropic properties of trabeculae located at ultra-distal radius were investigated by using the trabecular bone scores (TBS) calculated along directions...Background: When applied to trabecular bone X-ray images, the anisotropic properties of trabeculae located at ultra-distal radius were investigated by using the trabecular bone scores (TBS) calculated along directions parallel and perpendicular to the forearm. Methodology: Data from more than two hundred subjects were studied retrospectively. A DXA (GE Lunar Prodigy) scan of the forearm was performed on each subject to measure the bone mineral density (BMD) value at the location of ultra-distal radius, and an X-ray digital image of the same forearm was taken on the same day. The values of trabecular bone score along the direction perpendicular to the forearm, TBS<sub>x</sub>, and along the direction parallel to the forearm, TBS<sub>y</sub>, were calculated respectively. The statistics of TBS<sub>x</sub> and TBS<sub>y</sub> were calculated, and the anisotropy of the trabecular bone, which was defined as the ratio of TBS<sub>y</sub> to TBS<sub>x</sub> and changed with subjects’ BMD and age, was reported and analyzed. Results: The results show that the correlation coefficient between TBS<sub>x</sub> and TBS<sub>y</sub> was 0.72 (p BMD and age was reported. The results showed that decreased trabecular bone anisotropy was associated with deceased BMD and increased age in the subject group. Conclusions: This study shows that decreased trabecular bone anisotropy was associated with decreased BMD and increased age.展开更多
AIM： To retrospectively evaluate the computed tomography （CT）/magnetic resonance imaging （MRI） imaging features of epithelioid angiomyolipoma of the liver （Epi-HAML）, with pathology as a reference. METHODS： Th...AIM： To retrospectively evaluate the computed tomography （CT）/magnetic resonance imaging （MRI） imaging features of epithelioid angiomyolipoma of the liver （Epi-HAML）, with pathology as a reference. METHODS： The CT/MRI findings （number, diameter, lobar location, and appearance of lesions） in a series of 10 patients with 12 pathologically proven epithelioid angiomyolipomas of the liver were retrospectively analyzed. The imaging features, including attenuation/ signal intensity characteristics, presence of fat, hypervascular, outer rim, and vessels within lesion, were evaluated and compared with that of non-Epi- HAML in 11 patients （13 lesions）. The Fisher exact test was used to compare difference in probability of imaging features between the two types. RESULTS： For 21 patients, CT images of 15 patients and MR images of six patients were available. No patient underwent two examinations. For the 15 patients with a CT scan, all HAML lesions in the two groups （10 Epi-HAML and seven non-Epi-HAML） manifested as hypoattenuation. For the six patients with MRI, all lesions （two Epi-HAML and six non-Epi- HAML） were hypointense on TlWI （fat suppression） and hyperintense on T2WI. There were 10 non-Epi-HAML, but only two Epi-HAML lesions showed the presence of fat, which significantly different between the two types （P = 0.005）. On the dynamic contrast enhancement （DCE） imaging, eight Epi-HAML, and 13 non-Epi lesions manifested as hypervascular. Punctate or curved vessels were displayed in 10 Epi-HAML as well as in nine non- Epi lesions and outer rim enhancement could be found with eight Epi-HAML as well as six non-Epi lesions. CONCLUSION： Little or no presence of adipose tissue was found to be an imaging feature of Epi- HAML, compared with the non-Epi type. In addition, hypervascularity with opacification of central punctiform or filiform vessels on DCE would be a characteristic enhancement pattern for Epi-HAML.展开更多
Primary gastric plasmacytoma (GP) is a rare extramedullary plasmacytoma with clinical and imaging features that are common among other gastric tumors, such as gastric adenocarcinomas, gastric stromal tumors, and lymph...Primary gastric plasmacytoma (GP) is a rare extramedullary plasmacytoma with clinical and imaging features that are common among other gastric tumors, such as gastric adenocarcinomas, gastric stromal tumors, and lymphomas. Here, we present a histologically confirmed case of primary GP examined with biphasic computed tomography (CT), magnetic resonance imaging (MRI), and endosonography. A well-circumscribed extraluminal mass appearing as homogeneous attenuation/intensity with gradual enhancement was identified on biphasic enhancement CT and MRI. This mass was hyperintense on diffusion-weighted imaging and hypointense on the apparent diffusion coefficient map, implying that water diffusion in the mass was restricted. In addition, endosonography indicated a low echogenic mass in the gastric wall. These imaging findings increase the available knowledge about imaging of this disease and provide valuable information for differentiating primary GP from common gastric tumors.展开更多
AIM: To investigate whether congenital lumbar spinal stenosis(CLSS) is associated with a specific degenerative changes of the lumbar spine. METHODS: The lumbar spine magnetic resonance imaging studies of 52 subjects w...AIM: To investigate whether congenital lumbar spinal stenosis(CLSS) is associated with a specific degenerative changes of the lumbar spine. METHODS: The lumbar spine magnetic resonance imaging studies of 52 subjects with CLSS and 48 control subjects were retrospectively evaluated. In each examination, the five lumbar levels were assessed for the presence or absence of circumferential or shallow annular bulges, annular tears, anterior or posterior disc herniations, epidural lipomatosis, Schmorl's nodes,spondylolisthesis, pars defects, and stress reactions of the posterior vertebral elements. RESULTS: Compared to control individuals, subjects with CLSS exhibited increased incidence of circumferential and shallow annular bulges, annular tears, discherniations and spondylolisthesis(P < 0.05). CONCLUSION: CLSS is associated with increased incidence of degenerative changes in specific osseous and soft-tissue elements of the lumbar spine.展开更多
Inflammatory fibroid polyp(IFP) is a rare benign lesion of the gastrointestinal tract. We report a case of computed tomography(CT) imaging finding of a gastric IFP with massive fibrosis. CT scans showed thickening of ...Inflammatory fibroid polyp(IFP) is a rare benign lesion of the gastrointestinal tract. We report a case of computed tomography(CT) imaging finding of a gastric IFP with massive fibrosis. CT scans showed thickening of submucosal layer with overlying mucosal hyperenhancement in the gastric antrum. The submucosal layer showed increased enhancement on delayed phase imaging. An antrectomy with gastroduodenostomy was performed because gastric cancer was suspected, particularly signet ring cell carcinoma. The histopathological diagnosis was an IFP with massive fibrosis. The authors suggest that when the submucosal layer of the gastric wall is markedly thickened with delayed enhancement and preservation of the mucosal layer, an IFP with massive fibrosis should be considered in the differential diagnosis.展开更多
BACKGROUND Most melanomas identified in the stomach are metastatic;primary gastric melanoma(PGM)is extremely rare,and the relevant studies are relatively scarce.PGM may be incorrectly diagnosed as other gastric malign...BACKGROUND Most melanomas identified in the stomach are metastatic;primary gastric melanoma(PGM)is extremely rare,and the relevant studies are relatively scarce.PGM may be incorrectly diagnosed as other gastric malignant tumor types.CASE SUMMARY We describe a rare case of PGM confirmed through long-term clinical observation and pathological diagnosis.A 67-year-old woman presented to our hospital with recurrent chest tightness and chest pain.Digital gastrointestinal radiography revealed a circular shadow in the gastric cardia.Computed tomography(CT)revealed a heterogeneous tumor with uneven enhancement.Enlarged lymph nodes were noted in the lesser curvature of the stomach.On magnetic resonance imaging(MRI),T1-and T2-weighted imaging revealed hyperintensity in and hypointensity in the tumor,respectively,both of which increased substantially after uneven enhancement.Near total gastrectomy was performed,and the tumor was pathologically confirmed to be a gastric melanoma.Because no other possible primary site of malignant melanoma was suspected,a clinical diagnosis of PGM was made.The patient was followed for nearly 5 years,during which she received CT reexamination,but no recurrence or metastasis was observed.CONCLUSION Certain imaging characteristics could be revealed in PGM.Imaging examination can be of great value in preoperative diagnosis,differential diagnosis,and followup of patients with PGM.展开更多
BACKGROUND Synovial sarcoma(SS)accounting for 6%-10%of primary soft tissue malignancies mainly occurs in deep soft tissue adjacent to joints of the limbs.Primary pulmonary SS(PPSS)is rare and has a poor prognosis.Case...BACKGROUND Synovial sarcoma(SS)accounting for 6%-10%of primary soft tissue malignancies mainly occurs in deep soft tissue adjacent to joints of the limbs.Primary pulmonary SS(PPSS)is rare and has a poor prognosis.Cases of secondary distant metastases of PPSS occur rarely and there is a lack of corresponding imaging reports.We summarized the imaging findings of PPSS with multiple metastases confirmed by surgery and pathology,and shared valuable information on PPSS.CASE SUMMARY A 43-year-old female patient had a solid space occupying lesion in the right upper lobe of the lung.The results of a hemogram,erythrocyte sedimentation rate(ESR)and tumor markers were all within the normal range,tuberculin skin test(5 TU PPD)was negative(-).Chest computed tomography examination showed similar round soft tissue density in the posterior segment of the right upper lobe.Thoracoscopic-assisted wedge resection of the right upper lobe of the lung,right upper lobe resection and lymph node dissection were performed.Nine months after surgery,ultrasound examination showed multiple metastases on the chest wall and kidney.CONCLUSION PPSS is a rare malignant lung tumor with strong invasiveness,early distant metastasis and poor prognosis.There are very few imaging reports.PPSS is often manifested as irregular tumor and calcification,and the metastases have extremely low echo on ultrasonography.Contrast-enhanced ultrasound indicates that the arterial phase of tumor metastases shows rapid centripetal high enhancement,manifested as“fast forward and fast regression”.展开更多
Intracranial incidental findings on magnetic resonance imaging(MRI) of the brain continue to generate interest in healthy control,research,and clinical subjects.However,in clinical practice,the discovery of incidental...Intracranial incidental findings on magnetic resonance imaging(MRI) of the brain continue to generate interest in healthy control,research,and clinical subjects.However,in clinical practice,the discovery of incidental findings acts as a "distractor".This review is based on existing heterogeneous reports,their clinical implications,and how the results of incidental findings influence clinical management.This draws attention to the followings:(1) the prevalence of clinically significant incidental findings is low;(2) there is a lack of a systematic approach to classification;and discusses(3) how to deal with the detected incidental findings based a proposed common clinical profile.Individualized neurological care requires an active discussion regarding the need for neuroimaging.Clinical significance of incidental findings should be decided based on lesion's neuroradiologic characteristics in the given clinical context.Available evidence suggests that the outcome of an incidentally found "serious lesion in children" is excellent.Future studies of intracranial incidental findings on pediatric brain MRI should be focused on a homogeneous population.The study should address this clinical knowledge based review powered by the statistical analyses.展开更多
Objective： To investigate the imaging features of primary hepatic leiomyoma. Methods： 3 patients of primary hepatic leiomyoma confirmed by pathology without immunodeficiency were retrospectively analyzed about CT an...Objective： To investigate the imaging features of primary hepatic leiomyoma. Methods： 3 patients of primary hepatic leiomyoma confirmed by pathology without immunodeficiency were retrospectively analyzed about CT and MRI findings, clinical and pathological correlation. 2 cases had routine CT scan, 2 cases had routine MRI. Results： 2 case CT scans showed low-density lesions, 2 cases MRI showed lesions with long T1 and long T2 signal. One case of uniform density and signal showed homogeneous enhancement; two cases showed uneven density and signal, of which one case was inhomogeneous enhancement. 3 cases presented pseudocapsule without hepatic cirrhosis and venous tumor thrombus. Pathology showed spindle tumor cell proliferation and capillary hyperplasia; one case showed central hyalinization and one case central liquefaction necrosis. Conclusion： Primary hepatic leiomyoma is a hypervascular tumor, and CT and MRI help in the diagnosis.展开更多
Objective: To assess the importance of incidental extraspinal findings on Magnetic Resonance Imaging of the lumbar spine in two hospital facilities. Materials and Methods: It was a descriptive and retrospective study ...Objective: To assess the importance of incidental extraspinal findings on Magnetic Resonance Imaging of the lumbar spine in two hospital facilities. Materials and Methods: It was a descriptive and retrospective study from November 2015 to March 2016. The records of patients who had done a Magnetic Resonance Imaging (MRI) scan of the lumbar spine were re-read in search of incidental findings. The incidental findings found were classified using Colonography Reporting and Data System(C-RADS) classification of extracolonic lesions to assess clinical significance. The prevalence of incidental findings was calculated for each facility, as well as the distribution according to age, the organs involved and the clinical importance. A non-detection rate was calculated by confronting the findings of the study with the original reports. Results: The prevalence of incidental findings was respectively 33% (19 out of 36) in Jordan Medical Center (JMC) in Yaounde and 27.74% (106 out of 292) in Jacques Monod Hospital. The extraspinal incidental findings were classified mainly as extracolonic 2 (E2): 58% in each facility. The percentage detection of incidental findings was 5% at JMS and 1.7% at Jacques Monod Hospital. Conclusion: Extraspinal incidental findings are frequent in both hospitals. However, the rate of detection remains very low.展开更多
Objective To analyze the imaging character and surgical therapy of cavernous hemangiomas in cavernous sinus(CSHs).Methods From 2001 to 2008,13 patients with CSHs were surgically treated in our department. The diameter...Objective To analyze the imaging character and surgical therapy of cavernous hemangiomas in cavernous sinus(CSHs).Methods From 2001 to 2008,13 patients with CSHs were surgically treated in our department. The diameters of CSHs varied from 3. 5 cm to 6. 0 cm. Results All the patients were operated on with no mortality.展开更多
The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese...The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in 2025.SXI is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit.SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere.SWCX provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field lines.The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours.SXI is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States.展开更多
Astronomical imaging technologies are basic tools for the exploration of the universe,providing basic data for the research of astronomy and space physics.The Soft X-ray Imager(SXI)carried by the Solar wind Magnetosph...Astronomical imaging technologies are basic tools for the exploration of the universe,providing basic data for the research of astronomy and space physics.The Soft X-ray Imager(SXI)carried by the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)aims to capture two-dimensional(2-D)images of the Earth’s magnetosheath by using soft X-ray imaging.However,the observed 2-D images are affected by many noise factors,destroying the contained information,which is not conducive to the subsequent reconstruction of the three-dimensional(3-D)structure of the magnetopause.The analysis of SXI-simulated observation images shows that such damage cannot be evaluated with traditional restoration models.This makes it difficult to establish the mapping relationship between SXIsimulated observation images and target images by using mathematical models.We propose an image restoration algorithm for SXIsimulated observation images that can recover large-scale structure information on the magnetosphere.The idea is to train a patch estimator by selecting noise–clean patch pairs with the same distribution through the Classification–Expectation Maximization algorithm to achieve the restoration estimation of the SXI-simulated observation image,whose mapping relationship with the target image is established by the patch estimator.The Classification–Expectation Maximization algorithm is used to select multiple patch clusters with the same distribution and then train different patch estimators so as to improve the accuracy of the estimator.Experimental results showed that our image restoration algorithm is superior to other classical image restoration algorithms in the SXI-simulated observation image restoration task,according to the peak signal-to-noise ratio and structural similarity.The restoration results of SXI-simulated observation images are used in the tangent fitting approach and the computed tomography approach toward magnetospheric reconstruction techniques,significantly improving the reconstruction results.Hence,the proposed technology may be feasible for processing SXI-simulated observation images.展开更多
Throughout the SMILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their performance.In order to understand the changes of the CCD370s within the sof...Throughout the SMILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their performance.In order to understand the changes of the CCD370s within the soft X-ray Imager,an initial characterisation of the devices has been carried out to give a baseline performance level.Three CCDs have been characterised,the two flight devices and the flight spa re.This has been carried out at the Open University in a bespo ke cleanroom measure ment facility.The results show that there is a cluster of bright pixels in the flight spa re which increases in size with tempe rature.However at the nominal ope rating tempe rature(-120℃) it is within the procure ment specifications.Overall,the devices meet the specifications when ope rating at -120℃ in 6 × 6 binned frame transfer science mode.The se rial charge transfer inefficiency degrades with temperature in full frame mode.However any charge losses are recovered when binning/frame transfer is implemented.展开更多
The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magne...The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time.By making assumptions about the magnetopause shape,we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic(MHD)simulation.The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE(Earth radius)and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1532113,11475170,11905041)Anhui Provincial Natural Science Foundation(Grant No.2208085MA18)Fundamental Research Funds for the Central Universities(Grant No.JZ2022HGTB0244)。
文摘In x-ray dark-field imaging using dual phase grating interferometer,multi-contrast signals are extracted from a set of acquired phase-stepping data by using the least-squares fitting algorithm.The extracted mean intensity,amplitude and visibility signals may be intrinsically biased.However,it is still unclear how large these biases are and how the data acquisition parameters influence the biases in the extracted signals.This work set out to address these questions.Analytical expressions of the biases of the extracted signals were theoretically derived by using a second-order Taylor series expansion.Extensive numerical simulations were performed to validate the theoretical results.It is illustrated that while the estimated mean intensity signal is always unbiased,the estimated amplitude and visibility signals are both positively biased.While the biases of the estimated amplitude signals are proportional to the inverse of the total number of phase steps,the biases of the estimated visibility signals are inversely proportional to the product of the total number of phase steps and the mean number of photons counted per phase step.Meanwhile,it is demonstrated that the dependence of the biases on the mean visibility is quite different from that of Talbot-Lau interferometer due to the difference in the intensity model.We expect that these results can be useful for data acquisition optimizations and interpretation of x-ray dark-field images.
文摘BACKGROUND Pneumoparotid is a rare disease associated with retrograde airflow into the ductal system.There is no established treatment for this disease,which has no known complications.Mouth puffing and playing wind instruments are known to be the causes of this disease.CASE SUMMARY We managed a case,in which pneumoparotid suddenly recurred 4 months after surgery for purulent parotiditis.The patient did not report any obvious etiological factors,such as mouth puffing or playing a wind instrument.We reviewed 128 articles(from 1941 to 2023)that reported on a total of 166 patients with pneumoparotid,including the patient from the present case report,with imaging findings.This is the first reported case of pneumoparotid following surgery for purulent parotitis.The etiology in our case was classified as idiopathic.CONCLUSION Imaging findings could be sufficient for accurate pneumoparotid diagnoses and the exclusion of complications;computed tomography could be useful.
基金financial support from the National Natural Science Foundation of China(Nos.22075284,51872287,and U2030118)the Youth Innovation Promotion Association CAS(No.2019304)+1 种基金the Fund of Mindu Innovation Laboratory(No.2021ZR201)the Scientific Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20210039)
文摘Scintillation semiconductors play increasingly important medical diagnosis and industrial inspection roles.Recently,two-dimensional(2D)perovskites have been shown to be promising materials for medical X-ray imaging,but they are mostly used in low-energy(≤130 keV)regions.Direct detection of MeV X-rays,which ensure thorough penetration of the thick shell walls of containers,trucks,and aircraft,is also highly desired in practical industrial applications.Unfortunately,scintillation semiconductors for high-energy X-ray detection are currently scarce.Here,This paper reports a 2D(C_(4)H_(9)NH_(3))_(2)PbBr_(4)single crystal with outstanding sensitivity and stability toward X-ray radiation that provides an ultra-wide detectable X-ray range of between 8.20 nGy_(air)s^(-1)(50 keV)and 15.24 mGy_(air)s^(-1)(9 MeV).The(C_(4)H_(9)NH_(3))_(2)PbBr_(4)single-crystal detector with a vertical structure is used for high-performance X-ray imaging,delivering a good spatial resolution of 4.3 Ip mm^(-1)in a plane-scan imaging system.Low ionic migration in the 2D perovskite enables the vertical device to be operated with hundreds of keV to MeV X-ray radiation at high bias voltages,leading to a sensitivity of 46.90μC Gy_(air)-1 cm^(-2)(-1.16 Vμm^(-1))with 9 MeV X-ray radiation,demonstrating that 2D perovskites have enormous potential for high-energy industrial applications.
文摘Angiomyolipomas(AMLs)represent the most common benign solid renal tumors.The frequency of their detection in the general population is increasing owing to advances in imaging technology.The objective of this review is to discuss computed tomography(CT)and magnetic resonance imaging findings for both typical and atypical renal AMLs,along with their associated complications.AMLs are typically defined as solid triphasic tumors composed of varying amounts of dysmorphic and tortuous blood vessels,smooth muscle components and adipose tissue.In an adult,a classical renal AML appears as a solid,heterogeneous renal cortical mass with macroscopic fat.However,up to 5%of AMLs contain minimal fat and cannot be reliably diagnosed by imaging.Fat-poor AMLs can appear as hyperattenuating masses on unenhanced CT and as hypointense masses on T2WI;other AMLs may be isodense or exhibit cystic components.Hemorrhage is the most common complication,and AMLs with hemorrhage can mimic other tumors,making their diagnosis challenging.Understanding the variable and heterogeneous nature of this neoplasm to correctly classify renal AMLs and to avoid misdiagnosis of other renal lesions is crucial.
基金financial support through a KekuléPh.D.fellowship by the Fonds der Chemischen Industrie(FCI)support from the China Scholarship Council(No.202106950013)。
文摘The parasitic hydrogen evolution reaction(HER)in the negative half-cell of vanadium redox flow batteries(VRFBs)causes severe efficiency losses.Thus,a deeper understanding of this process and the accompanying bubble formation is crucial.This benchmarking study locally analyzes the bubble distribution in thick,porous electrodes for the first time using deep learning-based image segmentation of synchrotron X-ray micro-tomograms.Each large three-dimensional data set was processed precisely in less than one minute while minimizing human errors and pointing out areas of increased HER activity in VRFBs.The study systematically varies the electrode potential and material,concluding that more negative electrode potentials of-200 m V vs.reversible hydrogen electrode(RHE)and lower cause more substantial bubble formation,resulting in bubble fractions of around 15%–20%in carbon felt electrodes.Contrarily,the bubble fractions stay only around 2%in an electrode combining carbon felt and carbon paper.The detected areas with high HER activity,such as the border subregion with more than 30%bubble fraction in carbon felt electrodes,the cutting edges,and preferential spots in the electrode bulk,are potential-independent and suggest that larger electrodes with a higher bulk-to-border ratio might reduce HER-related performance losses.The described combination of electrochemical measurements,local X-ray microtomography,AI-based segmentation,and 3D morphometric analysis is a powerful and novel approach for local bubble analysis in three-dimensional porous electrodes,providing an essential toolkit for a broad community working on bubble-generating electrochemical systems.
文摘Background: When applied to trabecular bone X-ray images, the anisotropic properties of trabeculae located at ultra-distal radius were investigated by using the trabecular bone scores (TBS) calculated along directions parallel and perpendicular to the forearm. Methodology: Data from more than two hundred subjects were studied retrospectively. A DXA (GE Lunar Prodigy) scan of the forearm was performed on each subject to measure the bone mineral density (BMD) value at the location of ultra-distal radius, and an X-ray digital image of the same forearm was taken on the same day. The values of trabecular bone score along the direction perpendicular to the forearm, TBS<sub>x</sub>, and along the direction parallel to the forearm, TBS<sub>y</sub>, were calculated respectively. The statistics of TBS<sub>x</sub> and TBS<sub>y</sub> were calculated, and the anisotropy of the trabecular bone, which was defined as the ratio of TBS<sub>y</sub> to TBS<sub>x</sub> and changed with subjects’ BMD and age, was reported and analyzed. Results: The results show that the correlation coefficient between TBS<sub>x</sub> and TBS<sub>y</sub> was 0.72 (p BMD and age was reported. The results showed that decreased trabecular bone anisotropy was associated with deceased BMD and increased age in the subject group. Conclusions: This study shows that decreased trabecular bone anisotropy was associated with decreased BMD and increased age.
文摘AIM： To retrospectively evaluate the computed tomography （CT）/magnetic resonance imaging （MRI） imaging features of epithelioid angiomyolipoma of the liver （Epi-HAML）, with pathology as a reference. METHODS： The CT/MRI findings （number, diameter, lobar location, and appearance of lesions） in a series of 10 patients with 12 pathologically proven epithelioid angiomyolipomas of the liver were retrospectively analyzed. The imaging features, including attenuation/ signal intensity characteristics, presence of fat, hypervascular, outer rim, and vessels within lesion, were evaluated and compared with that of non-Epi- HAML in 11 patients （13 lesions）. The Fisher exact test was used to compare difference in probability of imaging features between the two types. RESULTS： For 21 patients, CT images of 15 patients and MR images of six patients were available. No patient underwent two examinations. For the 15 patients with a CT scan, all HAML lesions in the two groups （10 Epi-HAML and seven non-Epi-HAML） manifested as hypoattenuation. For the six patients with MRI, all lesions （two Epi-HAML and six non-Epi- HAML） were hypointense on TlWI （fat suppression） and hyperintense on T2WI. There were 10 non-Epi-HAML, but only two Epi-HAML lesions showed the presence of fat, which significantly different between the two types （P = 0.005）. On the dynamic contrast enhancement （DCE） imaging, eight Epi-HAML, and 13 non-Epi lesions manifested as hypervascular. Punctate or curved vessels were displayed in 10 Epi-HAML as well as in nine non- Epi lesions and outer rim enhancement could be found with eight Epi-HAML as well as six non-Epi lesions. CONCLUSION： Little or no presence of adipose tissue was found to be an imaging feature of Epi- HAML, compared with the non-Epi type. In addition, hypervascularity with opacification of central punctiform or filiform vessels on DCE would be a characteristic enhancement pattern for Epi-HAML.
基金Supported by The Research Projects of Public Technology Application of Science and Technology of Shaoxing City,No.2013B70080
文摘Primary gastric plasmacytoma (GP) is a rare extramedullary plasmacytoma with clinical and imaging features that are common among other gastric tumors, such as gastric adenocarcinomas, gastric stromal tumors, and lymphomas. Here, we present a histologically confirmed case of primary GP examined with biphasic computed tomography (CT), magnetic resonance imaging (MRI), and endosonography. A well-circumscribed extraluminal mass appearing as homogeneous attenuation/intensity with gradual enhancement was identified on biphasic enhancement CT and MRI. This mass was hyperintense on diffusion-weighted imaging and hypointense on the apparent diffusion coefficient map, implying that water diffusion in the mass was restricted. In addition, endosonography indicated a low echogenic mass in the gastric wall. These imaging findings increase the available knowledge about imaging of this disease and provide valuable information for differentiating primary GP from common gastric tumors.
文摘AIM: To investigate whether congenital lumbar spinal stenosis(CLSS) is associated with a specific degenerative changes of the lumbar spine. METHODS: The lumbar spine magnetic resonance imaging studies of 52 subjects with CLSS and 48 control subjects were retrospectively evaluated. In each examination, the five lumbar levels were assessed for the presence or absence of circumferential or shallow annular bulges, annular tears, anterior or posterior disc herniations, epidural lipomatosis, Schmorl's nodes,spondylolisthesis, pars defects, and stress reactions of the posterior vertebral elements. RESULTS: Compared to control individuals, subjects with CLSS exhibited increased incidence of circumferential and shallow annular bulges, annular tears, discherniations and spondylolisthesis(P < 0.05). CONCLUSION: CLSS is associated with increased incidence of degenerative changes in specific osseous and soft-tissue elements of the lumbar spine.
文摘Inflammatory fibroid polyp(IFP) is a rare benign lesion of the gastrointestinal tract. We report a case of computed tomography(CT) imaging finding of a gastric IFP with massive fibrosis. CT scans showed thickening of submucosal layer with overlying mucosal hyperenhancement in the gastric antrum. The submucosal layer showed increased enhancement on delayed phase imaging. An antrectomy with gastroduodenostomy was performed because gastric cancer was suspected, particularly signet ring cell carcinoma. The histopathological diagnosis was an IFP with massive fibrosis. The authors suggest that when the submucosal layer of the gastric wall is markedly thickened with delayed enhancement and preservation of the mucosal layer, an IFP with massive fibrosis should be considered in the differential diagnosis.
基金Supported by the Medical Health Science and Technology Project of Zhejiang Province(2019RC028)
文摘BACKGROUND Most melanomas identified in the stomach are metastatic;primary gastric melanoma(PGM)is extremely rare,and the relevant studies are relatively scarce.PGM may be incorrectly diagnosed as other gastric malignant tumor types.CASE SUMMARY We describe a rare case of PGM confirmed through long-term clinical observation and pathological diagnosis.A 67-year-old woman presented to our hospital with recurrent chest tightness and chest pain.Digital gastrointestinal radiography revealed a circular shadow in the gastric cardia.Computed tomography(CT)revealed a heterogeneous tumor with uneven enhancement.Enlarged lymph nodes were noted in the lesser curvature of the stomach.On magnetic resonance imaging(MRI),T1-and T2-weighted imaging revealed hyperintensity in and hypointensity in the tumor,respectively,both of which increased substantially after uneven enhancement.Near total gastrectomy was performed,and the tumor was pathologically confirmed to be a gastric melanoma.Because no other possible primary site of malignant melanoma was suspected,a clinical diagnosis of PGM was made.The patient was followed for nearly 5 years,during which she received CT reexamination,but no recurrence or metastasis was observed.CONCLUSION Certain imaging characteristics could be revealed in PGM.Imaging examination can be of great value in preoperative diagnosis,differential diagnosis,and followup of patients with PGM.
文摘BACKGROUND Synovial sarcoma(SS)accounting for 6%-10%of primary soft tissue malignancies mainly occurs in deep soft tissue adjacent to joints of the limbs.Primary pulmonary SS(PPSS)is rare and has a poor prognosis.Cases of secondary distant metastases of PPSS occur rarely and there is a lack of corresponding imaging reports.We summarized the imaging findings of PPSS with multiple metastases confirmed by surgery and pathology,and shared valuable information on PPSS.CASE SUMMARY A 43-year-old female patient had a solid space occupying lesion in the right upper lobe of the lung.The results of a hemogram,erythrocyte sedimentation rate(ESR)and tumor markers were all within the normal range,tuberculin skin test(5 TU PPD)was negative(-).Chest computed tomography examination showed similar round soft tissue density in the posterior segment of the right upper lobe.Thoracoscopic-assisted wedge resection of the right upper lobe of the lung,right upper lobe resection and lymph node dissection were performed.Nine months after surgery,ultrasound examination showed multiple metastases on the chest wall and kidney.CONCLUSION PPSS is a rare malignant lung tumor with strong invasiveness,early distant metastasis and poor prognosis.There are very few imaging reports.PPSS is often manifested as irregular tumor and calcification,and the metastases have extremely low echo on ultrasonography.Contrast-enhanced ultrasound indicates that the arterial phase of tumor metastases shows rapid centripetal high enhancement,manifested as“fast forward and fast regression”.
文摘Intracranial incidental findings on magnetic resonance imaging(MRI) of the brain continue to generate interest in healthy control,research,and clinical subjects.However,in clinical practice,the discovery of incidental findings acts as a "distractor".This review is based on existing heterogeneous reports,their clinical implications,and how the results of incidental findings influence clinical management.This draws attention to the followings:(1) the prevalence of clinically significant incidental findings is low;(2) there is a lack of a systematic approach to classification;and discusses(3) how to deal with the detected incidental findings based a proposed common clinical profile.Individualized neurological care requires an active discussion regarding the need for neuroimaging.Clinical significance of incidental findings should be decided based on lesion's neuroradiologic characteristics in the given clinical context.Available evidence suggests that the outcome of an incidentally found "serious lesion in children" is excellent.Future studies of intracranial incidental findings on pediatric brain MRI should be focused on a homogeneous population.The study should address this clinical knowledge based review powered by the statistical analyses.
文摘Objective： To investigate the imaging features of primary hepatic leiomyoma. Methods： 3 patients of primary hepatic leiomyoma confirmed by pathology without immunodeficiency were retrospectively analyzed about CT and MRI findings, clinical and pathological correlation. 2 cases had routine CT scan, 2 cases had routine MRI. Results： 2 case CT scans showed low-density lesions, 2 cases MRI showed lesions with long T1 and long T2 signal. One case of uniform density and signal showed homogeneous enhancement; two cases showed uneven density and signal, of which one case was inhomogeneous enhancement. 3 cases presented pseudocapsule without hepatic cirrhosis and venous tumor thrombus. Pathology showed spindle tumor cell proliferation and capillary hyperplasia; one case showed central hyalinization and one case central liquefaction necrosis. Conclusion： Primary hepatic leiomyoma is a hypervascular tumor, and CT and MRI help in the diagnosis.
文摘Objective: To assess the importance of incidental extraspinal findings on Magnetic Resonance Imaging of the lumbar spine in two hospital facilities. Materials and Methods: It was a descriptive and retrospective study from November 2015 to March 2016. The records of patients who had done a Magnetic Resonance Imaging (MRI) scan of the lumbar spine were re-read in search of incidental findings. The incidental findings found were classified using Colonography Reporting and Data System(C-RADS) classification of extracolonic lesions to assess clinical significance. The prevalence of incidental findings was calculated for each facility, as well as the distribution according to age, the organs involved and the clinical importance. A non-detection rate was calculated by confronting the findings of the study with the original reports. Results: The prevalence of incidental findings was respectively 33% (19 out of 36) in Jordan Medical Center (JMC) in Yaounde and 27.74% (106 out of 292) in Jacques Monod Hospital. The extraspinal incidental findings were classified mainly as extracolonic 2 (E2): 58% in each facility. The percentage detection of incidental findings was 5% at JMS and 1.7% at Jacques Monod Hospital. Conclusion: Extraspinal incidental findings are frequent in both hospitals. However, the rate of detection remains very low.
文摘Objective To analyze the imaging character and surgical therapy of cavernous hemangiomas in cavernous sinus(CSHs).Methods From 2001 to 2008,13 patients with CSHs were surgically treated in our department. The diameters of CSHs varied from 3. 5 cm to 6. 0 cm. Results All the patients were operated on with no mortality.
基金funding and support from the United Kingdom Space Agency(UKSA)the European Space Agency(ESA)+5 种基金funded and supported through the ESA PRODEX schemefunded through PRODEX PEA 4000123238the Research Council of Norway grant 223252funded by Spanish MCIN/AEI/10.13039/501100011033 grant PID2019-107061GB-C61funding and support from the Chinese Academy of Sciences(CAS)funding and support from the National Aeronautics and Space Administration(NASA)。
文摘The Soft X-ray Imager(SXI)is part of the scientific payload of the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission.SMILE is a joint science mission between the European Space Agency(ESA)and the Chinese Academy of Sciences(CAS)and is due for launch in 2025.SXI is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the SMILE orbit.SXI is sensitive to the soft X-rays produced by the Solar Wind Charge eXchange(SWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s exosphere.SWCX provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field lines.The sensitivity of the SXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of SMILE will enable such movements to be tracked for segments lasting many hours.SXI is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United States.
基金supported by the National Natural Science Foundation of China(Grant Nos.42322408,42188101,41974211,and 42074202)the Key Research Program of Frontier Sciences,Chinese Academy of Sciences(Grant No.QYZDJ-SSW-JSC028)+1 种基金the Strategic Priority Program on Space Science,Chinese Academy of Sciences(Grant Nos.XDA15052500,XDA15350201,and XDA15014800)supported by the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.Y202045)。
文摘Astronomical imaging technologies are basic tools for the exploration of the universe,providing basic data for the research of astronomy and space physics.The Soft X-ray Imager(SXI)carried by the Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)aims to capture two-dimensional(2-D)images of the Earth’s magnetosheath by using soft X-ray imaging.However,the observed 2-D images are affected by many noise factors,destroying the contained information,which is not conducive to the subsequent reconstruction of the three-dimensional(3-D)structure of the magnetopause.The analysis of SXI-simulated observation images shows that such damage cannot be evaluated with traditional restoration models.This makes it difficult to establish the mapping relationship between SXIsimulated observation images and target images by using mathematical models.We propose an image restoration algorithm for SXIsimulated observation images that can recover large-scale structure information on the magnetosphere.The idea is to train a patch estimator by selecting noise–clean patch pairs with the same distribution through the Classification–Expectation Maximization algorithm to achieve the restoration estimation of the SXI-simulated observation image,whose mapping relationship with the target image is established by the patch estimator.The Classification–Expectation Maximization algorithm is used to select multiple patch clusters with the same distribution and then train different patch estimators so as to improve the accuracy of the estimator.Experimental results showed that our image restoration algorithm is superior to other classical image restoration algorithms in the SXI-simulated observation image restoration task,according to the peak signal-to-noise ratio and structural similarity.The restoration results of SXI-simulated observation images are used in the tangent fitting approach and the computed tomography approach toward magnetospheric reconstruction techniques,significantly improving the reconstruction results.Hence,the proposed technology may be feasible for processing SXI-simulated observation images.
文摘Throughout the SMILE mission the satellite will be bombarded by radiation which gradually damages the focal plane devices and degrades their performance.In order to understand the changes of the CCD370s within the soft X-ray Imager,an initial characterisation of the devices has been carried out to give a baseline performance level.Three CCDs have been characterised,the two flight devices and the flight spa re.This has been carried out at the Open University in a bespo ke cleanroom measure ment facility.The results show that there is a cluster of bright pixels in the flight spa re which increases in size with tempe rature.However at the nominal ope rating tempe rature(-120℃) it is within the procure ment specifications.Overall,the devices meet the specifications when ope rating at -120℃ in 6 × 6 binned frame transfer science mode.The se rial charge transfer inefficiency degrades with temperature in full frame mode.However any charge losses are recovered when binning/frame transfer is implemented.
基金support from the UK Space Agency under Grant Number ST/T002964/1partly supported by the International Space Science Institute(ISSI)in Bern,through ISSI International Team Project Number 523(“Imaging the Invisible:Unveiling the Global Structure of Earth’s Dynamic Magnetosphere”)。
文摘The Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)Soft X-ray Imager(SXI)will shine a spotlight on magnetopause dynamics during magnetic reconnection.We simulate an event with a southward interplanetary magnetic field turning and produce SXI count maps with a 5-minute integration time.By making assumptions about the magnetopause shape,we find the magnetopause standoff distance from the count maps and compare it with the one obtained directly from the magnetohydrodynamic(MHD)simulation.The root mean square deviations between the reconstructed and MHD standoff distances do not exceed 0.2 RE(Earth radius)and the maximal difference equals 0.24 RE during the 25-minute interval around the southward turning.
