Susceptibility weighted imaging(SWI) is a recently developed magnetic resonance imaging(MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the...Susceptibility weighted imaging(SWI) is a recently developed magnetic resonance imaging(MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the magnetic susceptibility differences of various compounds including deoxygenated blood, blood products, iron and calcium, thus enabling a new source of contrast in MR. In this review, we illustrate its basic clinical applications in neuroimaging. SWI is based on a fully velocity-compensated, high-resolution, three dimensional gradientecho sequence using magnitude and phase images either separately or in combination with each other, in order to characterize brain tissue. SWI is particularly useful in the setting of trauma and acute neurologic presentations suggestive of stroke, but can also characterize occult low-flow vascular malformations, cerebral microbleeds, intracranial calcifications, neurodegenerative diseases and brain tumors. Furthermore, advanced MRI post-processing technique with quantitative susceptibility mapping, enables detailed anatomical differentiation based on quantification of brain iron from SWI raw data.展开更多
Diffuse axonal injury（DAI）is axonal and small vessel injury produced by a sudden acceleration of the head by an external force,and is a major cause of death and severe disability（Paterakis et al.,2000）.Prognosis i...Diffuse axonal injury（DAI）is axonal and small vessel injury produced by a sudden acceleration of the head by an external force,and is a major cause of death and severe disability（Paterakis et al.,2000）.Prognosis is poorer in patients with apparent hemorrhage than in those without（Paterakis et al.,2000）.Therefore,it is important to identify the presence and precise position of hemorrhagic foci for a more accurate diagnosis.CT and magnetic resonance imaging（MRI）have long been applied in the diagnosis of DAI, but they are not sensitive enough for the detection of small hemorrhagic foci, and cannot meet the requirements for early diagnosis. A major advance in MRI has been the development of susceptibility weighted imaging （SWI）, which has greatly increased the ability to detect small hemorrhagic foci after DAI （Ashwal et al., 2006）.展开更多
AIM:To review the literature on the assessment of venous vessels to estimate the penumbra on T2*w imaging and susceptibility-weighted imaging (SWI). METHODS:Literature that reported on the assessment of penumbra by T2...AIM:To review the literature on the assessment of venous vessels to estimate the penumbra on T2*w imaging and susceptibility-weighted imaging (SWI). METHODS:Literature that reported on the assessment of penumbra by T2*w imaging or SWI and used a validation method was included. PubMed and relevant stroke and magnetic resonance imaging (MRI) related conference abstracts were searched. Abstracts that had overlapping content with full text articles were excluded. The retrieved literature was scanned for further relevant references. Only clinical literature published in English was considered, patients with Moya-Moya syndrome were disregarded. Data is given as cumulative absolute and relative values, ranges are given where appropriate. RESULTS:Forty-three publications including 1145 patients could be identified. T2*w imaging was used in 16 publications (627 patients), SWI in 26 publications (453 patients). Only one publication used both (65 patients). The cumulative presence of hypointense vessel sign was 54% (range 32%-100%) for T2* (668 patients) and 81% (range 34%-100%) for SWI (334 patients). There was rare mentioning of interrater agreement (6 publications, 210 patients) and reliability (1 publication, 20 patients) but the numbers reported ranged from good to excellent. In most publications (n = 22) perfusion MRI was used as a validation method (617 patients). More patients were scanned in the subacute than in the acute phase (596 patients vs 320 patients). Clinical outcome was reported in 13 publications (521 patients) but was not consistent. CONCLUSION:The low presence of vessels signs on T2*w imaging makes SWI much more promising. More research is needed to obtain formal validation and quantification.展开更多
Cerebrovascular disease is one of the fatal causes of Fabry disease (FD). Brain magnetic resonance imaging findings typically show lacunar infarcts in young patients with FD, but brain hemorrhages in FD are rarely rep...Cerebrovascular disease is one of the fatal causes of Fabry disease (FD). Brain magnetic resonance imaging findings typically show lacunar infarcts in young patients with FD, but brain hemorrhages in FD are rarely reported. We report two cases of FD focusing on cerebral microbleeds (CMBs). Susceptibility-weighted imaging (SWI) and T2*-weighted imaging reveal several lobar and deep CMBs in two patients with no medical history of stroke symptoms, hypertension, and anticoagulant/antiplatelet treatment. SWI can detect a greater number of CMBs than T2*-weighted imaging. Thus, SWI is an excellent tool for identifying underlying CMBs in FD.展开更多
Susceptibility weighted imaging(SWI)is a relatively new magnetic resonance imaging(MRI)technique that uses the difference in tissue magnetic susceptibility to image,and has unique value compared to traditional magneti...Susceptibility weighted imaging(SWI)is a relatively new magnetic resonance imaging(MRI)technique that uses the difference in tissue magnetic susceptibility to image,and has unique value compared to traditional magnetic resonance imaging.This article summarizes its application in the central nervous system and provides a reference for imaging diagnosis and clinical treatment.展开更多
BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tu...BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tumor. However, the treatment response is observed only in a fraction of patients due to the partial radiological response secondary to stabilization of abnormal vessels which does not essentially indicate a true antitumor effect. Perfusion-weighted magnetic resonance imaging(PWMRI) techniques have shown implicitness as a strong imaging biomarker for gliomas since they give hemodynamic information of blood vessels. Hence, there is a rapid expansion of PW-MRI related studies and clinical applications.AIM To determine the diagnostic performance of PW-MRI techniques including:(A)dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI); and(B)dynamic susceptibility contrast magnetic resonance imaging(DSC-MRI) for evaluating response to antiangiogenic therapy in patients with recurrent gliomas.METHODS Databases such as PubMed(MEDLINE included), EMBASE, and Google Scholar were searched for relevant original articles. The included studies were assessed for methodological quality with the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Medical imaging follow-up or histopathological analysis was used as the reference standard. The data were extracted by two reviewers independently, and then the sensitivity, specificity, summary receiver operating characteristic curve, area under the curve(AUC), and heterogeneity were calculated using Meta-Disc 1.4 software.RESULTS This study analyzed a total of six articles. The overall sensitivity for DCE-MRI and DSC-MRI was 0.69 [95% confidence interval(CI): 0.53-0.82], and the specificity was 0.99(95%CI: 0.93-1) by a random effects model(DerSimonianeeLaird model). The likelihood ratio(LR) +, LR-, and diagnostic odds ratio(DOR)were 12.84(4.54-36.28), 0.35(0.22-0.53), and 24.44(7.19-83.06), respectively. The AUC(± SE) was 0.9921(± 0.0120), and the Q* index(± SE) was 0.9640(± 0.0323).For DSC-MRI, the sensitivity was 0.73, the specificity was 0.98, the LR+ was 7.82,the LR-was 0.32, the DOR was 31.65, the AUC(± SE) was 0.9925(± 0.0132), and the Q* index was 0.9649(± 0.0363). For DCE-MRI, the sensitivity was 0.41, the specificity was 0.97, the LR+ was 5.34, the LR-was 0.71, the DOR was 8.76, the AUC(± SE) was 0.9922(± 0.2218), and the Q* index was 0.8935(± 0.3037).CONCLUSION This meta-analysis demonstrated a beneficial value of PW-MRI(DSC-MRI and DCE-MRI) in monitoring the response of recurrent gliomas to antiangiogenic therapy, with reasonable sensitivity, specificity, +LR, and-LR.展开更多
<strong>Introduction:</strong> Owing to the advanced development of MRI science, it causes obvious great changes of many diseases that affect the female genital system and affect their fertility. Hemorrhag...<strong>Introduction:</strong> Owing to the advanced development of MRI science, it causes obvious great changes of many diseases that affect the female genital system and affect their fertility. Hemorrhagic gynecological diseases especially endometriosis affect young females and cause cyclic pain, in addition to infertility. So early detection is essential for proper treatment. Susceptibility-weighted (SWI) as one of the most recent newly created MRI sequences is highly sensitive to detect products of hemorrhage within different gynecologic disorders with 94.7% sensitivity being more meticulous than conventional MRI sequences as T1 and T2. <strong>Aim of the Work:</strong> A comparison between T1 and T2 as conventional MRI sequences with susceptibility-weighted images (SWI) in many gynecologic disorders by the detection of the presence of internal products of hemorrhage at any stage. <strong>Subjects and Methods:</strong> 48 consecutive patients from Benha University clinics (age range, 17 - 60 years;mean age, 35.67 years). The patients included in the study were presenting with pelvic pain, irregular menses, Dyspareunia, and swelling. All with suspicious diagnosis of ovarian and extra-ovarian lesions. 38 patients out of the 48 patients were known to contain hemorrhagic disorder;all the patients underwent MRI routine pelvis protocol adding SWI sequence. <strong>Results:</strong> There was a greatly significant difference between SWI and conventional MRI sequences T1and T2 with sensitivity 94.7%, 57.9% and 33.3% respectively. <strong>Conclusion:</strong> SWI is a promising tool in the evaluation of hemorrhagic foci within different gynecological disorders. The great ability of detecting hemosiderin foci increases the value of SWI over conventional MRI or US.展开更多
Background Computed tomography （CT） is better than routine magnetic resonance imaging （MRI） in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging （SWI...Background Computed tomography （CT） is better than routine magnetic resonance imaging （MRI） in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging （SWI） in the detection and differentiation of intracranial calcification and hemorrhage. Methods Enrolled in this study were 35 patients including 13 cases of calcification demonstrated by CT and 22 cases of intracerebral hemorrhage. MR sequences used in all the subjects included axial T1WI, T2WI and SWI. The phase shift （PS） of calcification and hemorrhage on SWI was calculated and their signal features on corrected phase images were compared. The sensitivity of T1WI, T2WI and SWI in detecting intracranial calcification and hemorrhage was analyzed statistically. Results The detection rate of SWI for cranial calcification was 98.2%, significantly higher than that of T1WI and T2WI. It was not significantly different from that of CT （P 〉0.05）. There were 49 hemorrhagic lesions at different stages detected on SWI, 30 on T2WI and 18 on T1WI. The average PS of calcification and hemorrhage was ＋0.734±0.073 and -0.112±0.032 respectively （P 〈0.05）. The PS of calcification was positive and presented as a high signal or the mixed signal dominated by a high signal on the corrected phase images, whereas the PS of hemorrhage was negative and presented as a low signal or the mixed signal dominated by a low signal.Conclusions SWI can accurately demonstrate intracranial calcification, not dependant on CT. Being more sensitive than routine MRI in detecting micro-hemorrhage, SWI may play an important role in differentiating cerebral diseases associated with calcification or hemorrhage.展开更多
Previous neuropathological studies regarding traumatic brain injury have primarily focused on changes in large structures, for example, the clinical prognosis after cerebral contusion, intrace- rebral hematoma, and ep...Previous neuropathological studies regarding traumatic brain injury have primarily focused on changes in large structures, for example, the clinical prognosis after cerebral contusion, intrace- rebral hematoma, and epidural and subdural hematoma. In fact, many smaller injuries can also lead to severe neurological disorders. For example, cerebral microbleeds result in the dysfunc- tion of adjacent neurons and the disassociation between cortex and subcortical structures. These tiny changes cannot be adequately visualized on CT or conventional MRI. In contrast, gradient echo sequence-based susceptibility-weighted imaging is very sensitive to blood metabolites and microbleeds, and can be used to evaluate traumatic cerebral microbleeds with high sensitivity and accuracy. Cerebral microbleed can be considered as an important imaging marker for dif- fuse axonal injury with potential relevance for prognosis. For this reason, based on experimental and clinical studies, this study reviews the role of imaging data showing traumatic cerebral microbleeds in the evaluation of cerebral neuronal injury and neurofunctional loss.展开更多
Background Chronic liver disease causes aberrant formation of fibrous tissue that impedes normal liver function, ultimately resulting in liver cirrhosis. Iron uptake can occur within the hepatic parenchyma or within t...Background Chronic liver disease causes aberrant formation of fibrous tissue that impedes normal liver function, ultimately resulting in liver cirrhosis. Iron uptake can occur within the hepatic parenchyma or within the various nodules that form in a cirrhotic liver, termed siderotic nodules （SN）. We aimed to investigate the diagnostic performance of susceptibility weighted imaging （SWI） for detection of SN in patients with liver cirrhosis, and to evaluate the potential of SN numbers for assessing the degree of hepatic iron deposition, liver function, and liver fibrosis stage. Methods Ninety-one patients with chronic liver cirrhosis, who underwent megnetic resonance imagine （MRI） scanning in our department between November 2010 and April 2011, were included in the study. A 3.0T MRI scanner was used to acquire T1WI, T2WI, T2＊WI, and SWI images. The number of nodules, signal intensity ratio （SIR）, and contrast noise ratio （CNR） were recorded and analyzed by chi-square and ANOVA statistical tests. Correlation analysis was performed to evaluate the correlations between the number of SN and Child-Pugh classification, ferritin and hyaluronic acid levels. Results The sensitivity of SWI, T1WI, T2WI, and T2＊WI for detecting SN was 62.5%, 12.1%, 24.2% and 41.8%, respectively. SWI detected significantly more nodules than routine T1WI, T2WI, and T2＊WI procedures （P 〈0.05）. The SIR was the lowest in SWI （0.361±0.209）, as compared to T1WI （0.852±0.163）, T2WI （0.584±0.172）, and T2＊WI （0.497±0.196）. The CNR was the highest in SWI （13.932±5.637）, as compared to T1WI （9.147±5.785）, T2WI （9.771±5.490）, and T2＊WI （11.491±4.573）. The correlation coefficients of the number of SN with ferritin, Child-Pugh classification, and hyaluronic acid levels were 0.672, -0.055, and 0.163, respectively. Conclusions The sensitivity and contrast of SWI for detecting SN in patients with liver cirrhosis are higher than conventional MRI. The number of SN can help to assess the degree of iron deposition in patients with liver cirrhosis.展开更多
Objective： To provide a comprehensive and latest overview of susceptibility-weighted imaging （SWI） in the application of thrombolysis in acute ischemic stroke, and to update the decision-making effect and clinical ...Objective： To provide a comprehensive and latest overview of susceptibility-weighted imaging （SWI） in the application of thrombolysis in acute ischemic stroke, and to update the decision-making effect and clinical value of SWI on identifying stroke patients suitable for thrombolytic therapy and possible benefits and risks followed. Data Sources： Literatures referred to this review were collected from PubMed, Medline, and EMBASE published till May 2017, using the search terms including susceptibility-weighted imaging, gradient-echo, T2＊, thrombolysis, recombinant tissue plasminogen activator （rt-PA）, thrombolytic therapy, and stroke. Study Selection： Papers in EngLish or with available English abstracts were considered, with no limitation of study design. References were also identified from the bibliographies of identified articles and the authors＇ files. Results： SW1 is of guiding significance for thrombolytic therapy in stroke patients, it can predict the location and length of thrombus and ischemic penumbra. It is worthy of noting that susceptibility vessel sign （SVS） on SWI can be used to predict recanalization after thrombolytic therapy and whether it is better to implement endovascular thrombolectonqy in combination or alone. SW1 is sensitive in detecting cerebral microbleed （CMB）, and CMB might not be a contraindication for thrombolytic therapy, yet CMBs in multiple loci could possibly be related to intracranial hemorrhage （ICH） after thrombolysis. SVS and CMB on SWI sequence are of instructive value in performing antiplatelet therapy after thrombolytic therapy. Cerebral venous change on SWI is related to lower recanalization rate and poor outcome after thrombolysis. Conclusions： It seems that SWI can be applied to guide individualized thrombolytic therapies and assist clinicians in making better decisions by weighing benefits and risks. However, there still exist controversies about the relationship between signs on SWI and thrombolytic therapy.展开更多
Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-der...Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-derived stem cells labeled with ferumoxytol in middle cerebral artery occlusion-injured rats by 3.0 T MRI in vivo. 1 × 104 human adipose-derived stem cells labeled with ferumoxytol-heparin-protamine were transplanted into the brains of rats with middle cerebral artery occlusion. Neurologic impairment was scored at 1, 7, 14, and 28 days after transplantation. T2-weighted imaging and enhanced susceptibility-weighted angiography were used to observe transplanted cells. Results of imaging tests were compared with results of Prussian blue staining. The modified neurologic impairment scores were significantly lower in rats transplanted with cells at all time points except I day post-transplantation compared with rats without transplantation. Regions with hypointense signals on T2-weighted and enhanced susceptibility-weighted angiography images corresponded with areas stained by Prussian blue, suggesting the presence of superparamagnetic iron oxide particles within the engrafted cells. Enhanced susceptibility-weighted angiography image exhibited better sensitivity and contrast in tracing ferumoxytol-heparin-protamine-labeled human adipose-derived stem ceils compared with T2-weighted imaging in routine MRI.展开更多
Purpose: To describe the magnetic resonance imaging(MRI)features of orbital rhabdomyosarcoma(RMS).Methods: Thirty-nine patients with histopathologically confirmed orbital RMS were retrospectively reviewed. All patient...Purpose: To describe the magnetic resonance imaging(MRI)features of orbital rhabdomyosarcoma(RMS).Methods: Thirty-nine patients with histopathologically confirmed orbital RMS were retrospectively reviewed. All patients underwent orbital conventional MRI, including axial, sagittal,and coronal T1-weighted, T2-weighted, and postcontrast T1-weighted sequences. The location, shape, margin, and MRI signal of the 39 lesions were reviewed. DWI in 15 patients and susceptibility weighted imaging(SWI) in 2 patients were also analyzed.Results: Orbital MRI was available in 39 patients and revealed a soft tissue mass in the orbital region in all cases. Of the 39 patients, the primary tumor sites were limited to the orbital proper in 31 cases, while 28 cases had extraocular muscle invasion and 8 cases had extraorbital invasion. All lesions were unilateral. Thirty-three cases were well-defined soft tissue masses and 6 cases appeared as less well-defined softtissue masses. Thirty-four cases showed homogeneous isointense or slightly hypointense signals on T1-weighted imaging(T1WI) and hyperintense signal on T2-weighted imaging(T2WI) compared with extraocular muscles. Five cases had heterogeneous signals with focal areas of increased signal on T1WI or decreased signal on T2WI, including 1 case with hypointense signal on SWI. The mean apparent diffusion coefficient(ADC) value of the viable part of tumors was(0.925±0.09)×10-3mm2/ s. All cases showed moderate to marked enhancement after contrast administration.Conclusion: Several MRI features-including homogeneous isointense or slightly hypointense signal on T1WI and slightly hyperintense signal on T2WI, relative low ADC values, and moderate to marked enhancement, extraocular muscles invasion, and extraorbital extensionare helpful in the diagnosis of orbital RMS.展开更多
文摘Susceptibility weighted imaging(SWI) is a recently developed magnetic resonance imaging(MRI) technique that is increasingly being used to narrow the differential diagnosis of many neurologic disorders. It exploits the magnetic susceptibility differences of various compounds including deoxygenated blood, blood products, iron and calcium, thus enabling a new source of contrast in MR. In this review, we illustrate its basic clinical applications in neuroimaging. SWI is based on a fully velocity-compensated, high-resolution, three dimensional gradientecho sequence using magnitude and phase images either separately or in combination with each other, in order to characterize brain tissue. SWI is particularly useful in the setting of trauma and acute neurologic presentations suggestive of stroke, but can also characterize occult low-flow vascular malformations, cerebral microbleeds, intracranial calcifications, neurodegenerative diseases and brain tumors. Furthermore, advanced MRI post-processing technique with quantitative susceptibility mapping, enables detailed anatomical differentiation based on quantification of brain iron from SWI raw data.
基金supported by a grant from the Key Science and Technology Development Project of Nanjing Medical University in ChinaNo.08NMU054
文摘Diffuse axonal injury（DAI）is axonal and small vessel injury produced by a sudden acceleration of the head by an external force,and is a major cause of death and severe disability（Paterakis et al.,2000）.Prognosis is poorer in patients with apparent hemorrhage than in those without（Paterakis et al.,2000）.Therefore,it is important to identify the presence and precise position of hemorrhagic foci for a more accurate diagnosis.CT and magnetic resonance imaging（MRI）have long been applied in the diagnosis of DAI, but they are not sensitive enough for the detection of small hemorrhagic foci, and cannot meet the requirements for early diagnosis. A major advance in MRI has been the development of susceptibility weighted imaging （SWI）, which has greatly increased the ability to detect small hemorrhagic foci after DAI （Ashwal et al., 2006）.
文摘AIM:To review the literature on the assessment of venous vessels to estimate the penumbra on T2*w imaging and susceptibility-weighted imaging (SWI). METHODS:Literature that reported on the assessment of penumbra by T2*w imaging or SWI and used a validation method was included. PubMed and relevant stroke and magnetic resonance imaging (MRI) related conference abstracts were searched. Abstracts that had overlapping content with full text articles were excluded. The retrieved literature was scanned for further relevant references. Only clinical literature published in English was considered, patients with Moya-Moya syndrome were disregarded. Data is given as cumulative absolute and relative values, ranges are given where appropriate. RESULTS:Forty-three publications including 1145 patients could be identified. T2*w imaging was used in 16 publications (627 patients), SWI in 26 publications (453 patients). Only one publication used both (65 patients). The cumulative presence of hypointense vessel sign was 54% (range 32%-100%) for T2* (668 patients) and 81% (range 34%-100%) for SWI (334 patients). There was rare mentioning of interrater agreement (6 publications, 210 patients) and reliability (1 publication, 20 patients) but the numbers reported ranged from good to excellent. In most publications (n = 22) perfusion MRI was used as a validation method (617 patients). More patients were scanned in the subacute than in the acute phase (596 patients vs 320 patients). Clinical outcome was reported in 13 publications (521 patients) but was not consistent. CONCLUSION:The low presence of vessels signs on T2*w imaging makes SWI much more promising. More research is needed to obtain formal validation and quantification.
文摘Cerebrovascular disease is one of the fatal causes of Fabry disease (FD). Brain magnetic resonance imaging findings typically show lacunar infarcts in young patients with FD, but brain hemorrhages in FD are rarely reported. We report two cases of FD focusing on cerebral microbleeds (CMBs). Susceptibility-weighted imaging (SWI) and T2*-weighted imaging reveal several lobar and deep CMBs in two patients with no medical history of stroke symptoms, hypertension, and anticoagulant/antiplatelet treatment. SWI can detect a greater number of CMBs than T2*-weighted imaging. Thus, SWI is an excellent tool for identifying underlying CMBs in FD.
文摘Susceptibility weighted imaging(SWI)is a relatively new magnetic resonance imaging(MRI)technique that uses the difference in tissue magnetic susceptibility to image,and has unique value compared to traditional magnetic resonance imaging.This article summarizes its application in the central nervous system and provides a reference for imaging diagnosis and clinical treatment.
文摘BACKGROUND It is of vital importance to find radiologic biomarkers that can accurately predict treatment response. Usually, the initiation of antiangiogenic therapy causes a rapid decrease in the contrast enhancing tumor. However, the treatment response is observed only in a fraction of patients due to the partial radiological response secondary to stabilization of abnormal vessels which does not essentially indicate a true antitumor effect. Perfusion-weighted magnetic resonance imaging(PWMRI) techniques have shown implicitness as a strong imaging biomarker for gliomas since they give hemodynamic information of blood vessels. Hence, there is a rapid expansion of PW-MRI related studies and clinical applications.AIM To determine the diagnostic performance of PW-MRI techniques including:(A)dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI); and(B)dynamic susceptibility contrast magnetic resonance imaging(DSC-MRI) for evaluating response to antiangiogenic therapy in patients with recurrent gliomas.METHODS Databases such as PubMed(MEDLINE included), EMBASE, and Google Scholar were searched for relevant original articles. The included studies were assessed for methodological quality with the Quality Assessment of Diagnostic Accuracy Studies 2 tool. Medical imaging follow-up or histopathological analysis was used as the reference standard. The data were extracted by two reviewers independently, and then the sensitivity, specificity, summary receiver operating characteristic curve, area under the curve(AUC), and heterogeneity were calculated using Meta-Disc 1.4 software.RESULTS This study analyzed a total of six articles. The overall sensitivity for DCE-MRI and DSC-MRI was 0.69 [95% confidence interval(CI): 0.53-0.82], and the specificity was 0.99(95%CI: 0.93-1) by a random effects model(DerSimonianeeLaird model). The likelihood ratio(LR) +, LR-, and diagnostic odds ratio(DOR)were 12.84(4.54-36.28), 0.35(0.22-0.53), and 24.44(7.19-83.06), respectively. The AUC(± SE) was 0.9921(± 0.0120), and the Q* index(± SE) was 0.9640(± 0.0323).For DSC-MRI, the sensitivity was 0.73, the specificity was 0.98, the LR+ was 7.82,the LR-was 0.32, the DOR was 31.65, the AUC(± SE) was 0.9925(± 0.0132), and the Q* index was 0.9649(± 0.0363). For DCE-MRI, the sensitivity was 0.41, the specificity was 0.97, the LR+ was 5.34, the LR-was 0.71, the DOR was 8.76, the AUC(± SE) was 0.9922(± 0.2218), and the Q* index was 0.8935(± 0.3037).CONCLUSION This meta-analysis demonstrated a beneficial value of PW-MRI(DSC-MRI and DCE-MRI) in monitoring the response of recurrent gliomas to antiangiogenic therapy, with reasonable sensitivity, specificity, +LR, and-LR.
文摘<strong>Introduction:</strong> Owing to the advanced development of MRI science, it causes obvious great changes of many diseases that affect the female genital system and affect their fertility. Hemorrhagic gynecological diseases especially endometriosis affect young females and cause cyclic pain, in addition to infertility. So early detection is essential for proper treatment. Susceptibility-weighted (SWI) as one of the most recent newly created MRI sequences is highly sensitive to detect products of hemorrhage within different gynecologic disorders with 94.7% sensitivity being more meticulous than conventional MRI sequences as T1 and T2. <strong>Aim of the Work:</strong> A comparison between T1 and T2 as conventional MRI sequences with susceptibility-weighted images (SWI) in many gynecologic disorders by the detection of the presence of internal products of hemorrhage at any stage. <strong>Subjects and Methods:</strong> 48 consecutive patients from Benha University clinics (age range, 17 - 60 years;mean age, 35.67 years). The patients included in the study were presenting with pelvic pain, irregular menses, Dyspareunia, and swelling. All with suspicious diagnosis of ovarian and extra-ovarian lesions. 38 patients out of the 48 patients were known to contain hemorrhagic disorder;all the patients underwent MRI routine pelvis protocol adding SWI sequence. <strong>Results:</strong> There was a greatly significant difference between SWI and conventional MRI sequences T1and T2 with sensitivity 94.7%, 57.9% and 33.3% respectively. <strong>Conclusion:</strong> SWI is a promising tool in the evaluation of hemorrhagic foci within different gynecological disorders. The great ability of detecting hemosiderin foci increases the value of SWI over conventional MRI or US.
基金This study was supported by a grant from the National Natural Science Foundation of China （No. 30570531）.
文摘Background Computed tomography （CT） is better than routine magnetic resonance imaging （MRI） in detecting intracranial calcification. This study aimed to assess the value of MR susceptibility weighted imaging （SWI） in the detection and differentiation of intracranial calcification and hemorrhage. Methods Enrolled in this study were 35 patients including 13 cases of calcification demonstrated by CT and 22 cases of intracerebral hemorrhage. MR sequences used in all the subjects included axial T1WI, T2WI and SWI. The phase shift （PS） of calcification and hemorrhage on SWI was calculated and their signal features on corrected phase images were compared. The sensitivity of T1WI, T2WI and SWI in detecting intracranial calcification and hemorrhage was analyzed statistically. Results The detection rate of SWI for cranial calcification was 98.2%, significantly higher than that of T1WI and T2WI. It was not significantly different from that of CT （P 〉0.05）. There were 49 hemorrhagic lesions at different stages detected on SWI, 30 on T2WI and 18 on T1WI. The average PS of calcification and hemorrhage was ＋0.734±0.073 and -0.112±0.032 respectively （P 〈0.05）. The PS of calcification was positive and presented as a high signal or the mixed signal dominated by a high signal on the corrected phase images, whereas the PS of hemorrhage was negative and presented as a low signal or the mixed signal dominated by a low signal.Conclusions SWI can accurately demonstrate intracranial calcification, not dependant on CT. Being more sensitive than routine MRI in detecting micro-hemorrhage, SWI may play an important role in differentiating cerebral diseases associated with calcification or hemorrhage.
基金supported by grants from the State-Funded Construction Projects Key Clinical Specialist(2013-2015)the Hunan Provincial Science and Technology Department,No.2009FJ3092
文摘Previous neuropathological studies regarding traumatic brain injury have primarily focused on changes in large structures, for example, the clinical prognosis after cerebral contusion, intrace- rebral hematoma, and epidural and subdural hematoma. In fact, many smaller injuries can also lead to severe neurological disorders. For example, cerebral microbleeds result in the dysfunc- tion of adjacent neurons and the disassociation between cortex and subcortical structures. These tiny changes cannot be adequately visualized on CT or conventional MRI. In contrast, gradient echo sequence-based susceptibility-weighted imaging is very sensitive to blood metabolites and microbleeds, and can be used to evaluate traumatic cerebral microbleeds with high sensitivity and accuracy. Cerebral microbleed can be considered as an important imaging marker for dif- fuse axonal injury with potential relevance for prognosis. For this reason, based on experimental and clinical studies, this study reviews the role of imaging data showing traumatic cerebral microbleeds in the evaluation of cerebral neuronal injury and neurofunctional loss.
文摘Background Chronic liver disease causes aberrant formation of fibrous tissue that impedes normal liver function, ultimately resulting in liver cirrhosis. Iron uptake can occur within the hepatic parenchyma or within the various nodules that form in a cirrhotic liver, termed siderotic nodules （SN）. We aimed to investigate the diagnostic performance of susceptibility weighted imaging （SWI） for detection of SN in patients with liver cirrhosis, and to evaluate the potential of SN numbers for assessing the degree of hepatic iron deposition, liver function, and liver fibrosis stage. Methods Ninety-one patients with chronic liver cirrhosis, who underwent megnetic resonance imagine （MRI） scanning in our department between November 2010 and April 2011, were included in the study. A 3.0T MRI scanner was used to acquire T1WI, T2WI, T2＊WI, and SWI images. The number of nodules, signal intensity ratio （SIR）, and contrast noise ratio （CNR） were recorded and analyzed by chi-square and ANOVA statistical tests. Correlation analysis was performed to evaluate the correlations between the number of SN and Child-Pugh classification, ferritin and hyaluronic acid levels. Results The sensitivity of SWI, T1WI, T2WI, and T2＊WI for detecting SN was 62.5%, 12.1%, 24.2% and 41.8%, respectively. SWI detected significantly more nodules than routine T1WI, T2WI, and T2＊WI procedures （P 〈0.05）. The SIR was the lowest in SWI （0.361±0.209）, as compared to T1WI （0.852±0.163）, T2WI （0.584±0.172）, and T2＊WI （0.497±0.196）. The CNR was the highest in SWI （13.932±5.637）, as compared to T1WI （9.147±5.785）, T2WI （9.771±5.490）, and T2＊WI （11.491±4.573）. The correlation coefficients of the number of SN with ferritin, Child-Pugh classification, and hyaluronic acid levels were 0.672, -0.055, and 0.163, respectively. Conclusions The sensitivity and contrast of SWI for detecting SN in patients with liver cirrhosis are higher than conventional MRI. The number of SN can help to assess the degree of iron deposition in patients with liver cirrhosis.
文摘Objective： To provide a comprehensive and latest overview of susceptibility-weighted imaging （SWI） in the application of thrombolysis in acute ischemic stroke, and to update the decision-making effect and clinical value of SWI on identifying stroke patients suitable for thrombolytic therapy and possible benefits and risks followed. Data Sources： Literatures referred to this review were collected from PubMed, Medline, and EMBASE published till May 2017, using the search terms including susceptibility-weighted imaging, gradient-echo, T2＊, thrombolysis, recombinant tissue plasminogen activator （rt-PA）, thrombolytic therapy, and stroke. Study Selection： Papers in EngLish or with available English abstracts were considered, with no limitation of study design. References were also identified from the bibliographies of identified articles and the authors＇ files. Results： SW1 is of guiding significance for thrombolytic therapy in stroke patients, it can predict the location and length of thrombus and ischemic penumbra. It is worthy of noting that susceptibility vessel sign （SVS） on SWI can be used to predict recanalization after thrombolytic therapy and whether it is better to implement endovascular thrombolectonqy in combination or alone. SW1 is sensitive in detecting cerebral microbleed （CMB）, and CMB might not be a contraindication for thrombolytic therapy, yet CMBs in multiple loci could possibly be related to intracranial hemorrhage （ICH） after thrombolysis. SVS and CMB on SWI sequence are of instructive value in performing antiplatelet therapy after thrombolytic therapy. Cerebral venous change on SWI is related to lower recanalization rate and poor outcome after thrombolysis. Conclusions： It seems that SWI can be applied to guide individualized thrombolytic therapies and assist clinicians in making better decisions by weighing benefits and risks. However, there still exist controversies about the relationship between signs on SWI and thrombolytic therapy.
基金supported by the Science and Technology Plan Project of Dalian City in China,No.2014E14SF186
文摘Ferumoxytol, an iron replacement product, is a new type of superparamagnetic iron oxide ap- proved by the US Food and Drug Administration. Herein, we assessed the feasibility of tracking transplanted human adipose-derived stem cells labeled with ferumoxytol in middle cerebral artery occlusion-injured rats by 3.0 T MRI in vivo. 1 × 104 human adipose-derived stem cells labeled with ferumoxytol-heparin-protamine were transplanted into the brains of rats with middle cerebral artery occlusion. Neurologic impairment was scored at 1, 7, 14, and 28 days after transplantation. T2-weighted imaging and enhanced susceptibility-weighted angiography were used to observe transplanted cells. Results of imaging tests were compared with results of Prussian blue staining. The modified neurologic impairment scores were significantly lower in rats transplanted with cells at all time points except I day post-transplantation compared with rats without transplantation. Regions with hypointense signals on T2-weighted and enhanced susceptibility-weighted angiography images corresponded with areas stained by Prussian blue, suggesting the presence of superparamagnetic iron oxide particles within the engrafted cells. Enhanced susceptibility-weighted angiography image exhibited better sensitivity and contrast in tracing ferumoxytol-heparin-protamine-labeled human adipose-derived stem ceils compared with T2-weighted imaging in routine MRI.
文摘Purpose: To describe the magnetic resonance imaging(MRI)features of orbital rhabdomyosarcoma(RMS).Methods: Thirty-nine patients with histopathologically confirmed orbital RMS were retrospectively reviewed. All patients underwent orbital conventional MRI, including axial, sagittal,and coronal T1-weighted, T2-weighted, and postcontrast T1-weighted sequences. The location, shape, margin, and MRI signal of the 39 lesions were reviewed. DWI in 15 patients and susceptibility weighted imaging(SWI) in 2 patients were also analyzed.Results: Orbital MRI was available in 39 patients and revealed a soft tissue mass in the orbital region in all cases. Of the 39 patients, the primary tumor sites were limited to the orbital proper in 31 cases, while 28 cases had extraocular muscle invasion and 8 cases had extraorbital invasion. All lesions were unilateral. Thirty-three cases were well-defined soft tissue masses and 6 cases appeared as less well-defined softtissue masses. Thirty-four cases showed homogeneous isointense or slightly hypointense signals on T1-weighted imaging(T1WI) and hyperintense signal on T2-weighted imaging(T2WI) compared with extraocular muscles. Five cases had heterogeneous signals with focal areas of increased signal on T1WI or decreased signal on T2WI, including 1 case with hypointense signal on SWI. The mean apparent diffusion coefficient(ADC) value of the viable part of tumors was(0.925±0.09)×10-3mm2/ s. All cases showed moderate to marked enhancement after contrast administration.Conclusion: Several MRI features-including homogeneous isointense or slightly hypointense signal on T1WI and slightly hyperintense signal on T2WI, relative low ADC values, and moderate to marked enhancement, extraocular muscles invasion, and extraorbital extensionare helpful in the diagnosis of orbital RMS.
