Accuracy Of Magnetic Resonance Angiography Research Articles

Deep Learning-Based Magnetic Resonance Imaging in Diagnosis and Treatment of Intracranial Aneurysm.

This study was focused on the positioning of the intracranial aneurysm in the magnetic resonance imaging (MRI) images using the deep learning-based U-Net model, to realize the computer-aided diagnosis of the intracranial aneurysm. First, a network was established based on the three-dimensional (3D) U-Net model, and the collected image data were input into the network to realize the automatic location and segmentation of the aneurysm. The 3D convolutional neural network (CNN) network can extract the aneurysm blood vessels to locate and identify the areas of possible aneurysms. Next, 40 patients highly suspected of intracranial aneurysm were selected as research subjects, and they were subjected to magnetic resonance angiography (MRA) and digital subtraction angiography (DSA) examinations. The results showed that based on the U-Net algorithm model, 40 patients' hemangiomas were completely contained in the labeling bounding box, one patient's hemangioma was at the edge of the labeling bounding box, and 4 patients' hemangiomas were outside the labeling box. The final accuracy coefficient was 88.9%, and it was in good agreement with the doctor's manual labelling results. Under the 3D CNN network test, the sensitivity, specificity, and accuracy of DSA for intracranial aneurysm were 91.46%, 86.01%, and 90.2%, respectively; the sensitivity, specificity, and accuracy of MRA for intracranial aneurysm were 95.87%, 100%, and 97.19%, respectively. In conclusion, the 3D CNN can successfully realize the positioning of intracranial aneurysm in MRA images, providing a certain theoretical basis for subsequent imaging diagnosis of aneurysm.

Diagnostic Value of CT Angiography Combined with High-Resolution Magnetic Resonance Angiography in Vascular Lesions in Acute Stroke

Cerebrovascular disease is increasing rapidly because of its high morbidity and high mortality, which is a serious threat to human health. For the early diagnosis and treatment of diseases, the CT vascular noise combined with high-resolution magnetic resonance angiography in acute cerebral apoplexy vascular disease is adopted. 150 patients with ischemic stroke were selected, which were admitted to the Department of Radiology, Huizhou Central People’s Hospital, from January 2020 to December 2020. All patients accepted digital subtraction angiography (DSA), magnetic resonance angiography (MRA), and CT angiography (CTA) examination. Results. There were 76 cases of aneurysm in DSA examination, accounting for 46%; 69 cases with pulsating stenosis, accounting for 50.67%; and 5 cases of moyamoya disease, accounting for 3.33%. The number and proportion of cases of the above diseases in MRA examination were (75, 69, 71; 53.33%, 45.67%, 4%), and those in CTA examination were (71, 76, 3, 47.33%, 50.67%, 2%). Relative to the DSA gold standard, the sensitivity, specificity, and false positive rate of MRA were 81.51%, 95.19%, and 2.1, respectively, and those of CTA were 95.78%, 79.17%, and 11.0, respectively. The number of cases and accuracy of detection of cerebral aneurysms by MRA were (75, 96.57%), and those by CTA were (71, 91.2%), which was not statistically considerable, P > 0.05 . For the number of cases and the detection accuracy of cerebrovascular malformations, MRA was (38, 92.68%) and CTA was (37, 90.24%), which was not statistically considerable, P > 0.05 . Conclusion. The detection sensitivity and accuracy of MRA were better than those of CTA, while specific CTA was superior to MRA. The differences between the two detections were substantial ( P < 0.05 ), while the sensitivity and false positive rate were not remarkably different ( P > 0.05 ). Therefore, the combination of the two detections was of great significance to the diagnosis and treatment of stroke and other vascular diseases.

Comparison of contrast-enhanced magnetic resonance angiography and digital subtraction angiography in the evaluation of renal artery stenosis and detecting of accessory and polar arteries

Objectives: Renal artery stenosis (RAS) is the most common cause of secondary hypertension. RAS may cause renal insufficiency, uncontrolled hypertension and is associated with increased cardiovascular morbidity and mortality. We aimed to evaluate the accuracy of contrast enhanced Flash 3D Renal Magnetic Resonance Angiography (MRA) in the depiction of the RAS also detecting of accessory and polar renal arteries with intraarterial digital subtraction angiography (DSA) still serving as the reference standard. Methods: In this retrospective case-control study, we reviewed contrast enhanced Flash 3D Renal MRA and DSA of 71 patients who were suspected of having RAS and underwent DSA after MRA within 15 days. DSA was accepted as gold standart and the specificity, sensitivity and accuracy of MRA were determined. Results: Overall sensitivity and specificity values of contrast enhanced Flash 3D Renal MRA in detecting stenosis were 96.1% and 76.3% respectively. Conclusions: Contrast enhanced Flash 3D Renal MRA is a reliable noninvasive imaging modality in the diagnosis of RAS.

High-Resolution MRI to Evaluate Benefit of Middle Cerebral Artery Stenosis in Secondary Prevention in Patients with Acute Cerebral Infarction

High-resolution magnetic resonance (HRMRI) combined with magnetic resonance angiography (MRA) was used to analyze the correlation between the degree of infarction and the degree of cerebral vascular stenosis, and these patients are all have the trend to contain acute infarction. All patients were examined by CT cerebral angiography, which was analysed by conventional magnetic resonance imaging (MRI), high-Resolution (HRMRI) imaging, and cerebral vascular (MRA) imaging. The infarct size of each patient with cerebral infarction was calculated. The degree of middle cerebral artery stenosis was evaluated. Moreover, agnosis of acute cerebral infarction in middle cerebral artery region was calculated, and the correlation between acute cerebral infarction in middle cerebral artery region and the degree of cerebral vascular stenosis was analyzed. The specificity, sensitivity, and accuracy of magnetic resonance angiography (MRA) in the diagnosis of acute cerebral infarction in the blood supply area of the middle cerebral artery were 90.48%, 94.87%, and 93.94%. The coincidence rates for the degree of middle cerebral artery stenosis were 90.91% for mild stenosis, 92.31% for moderate stenosis, 93.75% for severe stenosis, and 85.71% for vascular occlusion, respectively. The K value was in good agreement with the results of CTA diagnosis (≥0.75). In conclusion, HRMRI can clearly indicated that the location of lesions with acute cerebral infarction, and MRA can show the degree of vascular stenosis, there is a close relationship between them.

Geometric parameters on MRA source images to differentiate small Proximal Posterior communicating artery aneurysms from Infundibular dilation.

We aimed to assess the accuracy of magnetic resonance angiography (MRA) in the differentiation of small aneurysms versus infundibular dilations (IDs) at the internal carotid artery-posterior communicating artery (ICA-PComA) junction, emphasizing the role of MRA axial source images. This retrospective study consisted of 83 focal arterial protrusions at ICA-PComA junction in 76 patients who underwent both MRA and digital subtraction angiography (DSA)/3-dimensional rotational angiography (3DRA). The diagnostic performance of MRA for differential diagnosis of aneurysm from ID was calculated using DSA/3DRA interpretation as the standard of reference. In addition, long-axis diameter, short-axis diameter, long-axis diameter/short-axis diameter (L/S) ratio, and angle of lesion (angle of the long-axis of lesion with respect to the x-axis) measured on MRA source images were compared between aneurysms and IDs. Sensitivity, specificity, and accuracy of MRA for distinguishing aneurysms from IDs were 74.4% (57.9-87.0%) to 76.9% (60.7-88.9%), 93.2% (81.3-98.6%) to 95.5% (84.5-99.4%), and 85.5% (76.1-92.3%), respectively. Significant differences were found for the long-axis diameter (P<.001), short-axis diameter (P<.001), L/S ratio (P<.05), and angle of the lesion (P<.001) on MRA axial source images between aneurysms and IDs. The angle of the lesion had the highest discriminatory ability (area under the curve = .966 [.902-.994]) to differentiate aneurysms from IDs. An angle of lesion >60° was 89.7% (75.8-97.1%) sensitive and 100% (92.0-100.0%) specific for diagnosis of aneurysm. MRA is a useful imaging modality for distinguishing between aneurysm and ID at the ICA-PComA junction. Furthermore, geometric parameters on MRA axial source images can provide added value in their differentiation.

Accuracy of Magnetic Resonance Angiography for Identifying Moderate to Severe Internal Carotid Artery Stenosis: Analysis of CREST trial (5516)

Accuracy of Magnetic Resonance Angiography for Identifying Moderate to Severe Internal Carotid Artery Stenosis: Analysis of CREST trial (5516)

Accuracy of non‐contrast quiescent‐interval single‐shot and quiescent‐interval single‐shot arterial spin‐labelled magnetic resonance angiography in assessment of peripheral arterial disease in a diabetic population

Diabetic patients with peripheral arterial disease (PAD) are challenging to assess. Non-contrast magnetic resonance angiography (MRA) offers a safe alternative in patients with renal impairment. The study objective is to evaluate accuracy of lower limb quiescent-interval single-shot (QISS) MRA and pedal QISS-arterial spin-labelled (ASL) MRA for detection of significant stenosis in diabetic patients with PAD. Combined QISS and QISS-ASL MRA was performed in 32 diabetic PAD patients (20 male, 12 female; mean 69years; 8 with critical ischaemia). Two readers assessed haemodynamically significant (>50%) stenosis and diagnostic confidence on MRA, against digital subtraction angiography (DSA) as the reference standard, with subgroup analysis of patients with severe renal impairment (n=7). Inter-reader agreement of stenosis and diagnostic confidence were evaluated. Test-retest reproducibility was evaluated in 10 subjects who underwent repeat MRA on a different day. At DSA, 262/645 segments (40.6%) had haemodynamically significant stenoses. MRA accuracy was 78.1% (478/612) and 75.6% (464/614), sensitivity 64.7% (161/249) and 77.5% (193/249), and specificity 87.3% (317/363) and 74.2% (271/365) for 2 readers. MRA accuracy was 80.9% and 80.7% for readers 1 and 2, respectively, in patients with severe renal impairment. QISS MRA but not pedal QISS-ASL MRA was considered of diagnostic image quality. Inter-reader agreement was moderate for stenosis (ĸ=0.60) and diagnostic confidence (ĸ=0.41). Test-retest reproducibility was high (ĸ=0.87) and moderate (ĸ=0.54) for individual readers. Quiescent-interval single-shot MRA has reasonable accuracy in a diabetic PAD population with high burden of disease, providing a non-contrast option in patients with renal impairment. QISS-ASL MRA requires further optimisation to be clinically feasible.

Diagnostic accuracy of magnetic resonance angiography for Budd-Chiari syndrome: A meta-analysis.

In recent years, the role of magnetic resonance angiography (MRA) in the diagnosis of Budd-Chiari Syndrome (BCS) has been the focus of various clinical studies. The purpose of the present study was to perform a meta-analysis of the diagnostic performance of MRA in patients with BCS by using digital subtraction angiography as a reference method. The search strategy for relevant research articles was based on the Cochrane Handbook for Systematic Reviews, and literature databases (including PubMed, Medline and China National Knowledge Infrastructure) and reference lists of retrieved studies published from 2000 to 2016 were searched. The Quality Assessment of Diagnostic Accuracy Studies tool was used to assess the methodological quality of these research studies by two reviewers independently. Summary estimates of the sensitivity, specificity, positive/negative likelihood ratio (LR+/-), diagnostic odds ratio (DOR) and the summary receiver operating characteristic (SROC) curve of MRA in identifying BCS were obtained. The pooled MRA estimates had a sensitivity of 97.6% [95% confidence interval (CI), 95.1-99.0%], a specificity of 70.7% (95% CI, 54.5-83.9%), an LR+ of 3.163 (95% CI, 2.03-4.94) and an LR- of 0.045 (95% CI, 0.02-0.09). The overall DOR was 94.053 (95% CI, 32.71-270.41). The area under the SROC curve was 0.972. In conclusion, MRA is an accurate modality for evaluating BCS.

Diagnostic accuracy of magnetic resonance angiography for acute pulmonary embolism - a systematic review and meta-analysis.

The aim of this meta-analysis was to evaluate the diagnostic accuracy of magnetic resonance angiography (MRA) for acute pulmonary embolism (PE). A systematic literature search was conducted that included studies from January 2000 to August 2015 using the electronic databases PubMed, Embase and Springer link. The summary receiver operating characteristic (SROC) curve, sensitivity, specificity, positive likelihood ratios (PLR), negative likelihood ratios (NLR), and diagnostic odds ratio (DOR) as well as the 95 % confidence intervals (CIs) were calculated to evaluate the diagnostic accuracy of MRA for acute PE. Meta-disc software version 1.4 was used to analyze the data. Five studies were included in this meta-analysis. The pooled sensitivity (86 %, 95 % CI: 81 % to 90 %) and specificity (99 %, 95 % CI: 98 % to 100 %) demonstrated that MRA diagnosis had limited sensitivity and high specificity in the detection of acute PE. The pooled estimate of PLR (41.64, 95 % CI: 17.97 to 96.48) and NLR (0.17, 95 % CI: 0.11 to 0.27) provided evidence for the low missed diagnosis and misdiagnosis rates of MRA for acute PE. The high diagnostic accuracy of MRA for acute PE was demonstrated by the overall DOR (456.51, 95 % CI: 178.38 - 1168.31) and SROC curves (AUC = 0.9902 ± 0.0061). MRA can be used for the diagnosis of acute PE. However, due to limited sensitivity, MRA cannot be used as a stand-alone test to exclude acute PE.

Diagnostic accuracy of magnetic resonance angiography for detection of coronary artery disease: a systematic review and meta-analysis.

To review the diagnostic performance of MR coronary angiography (MRCA) for coronary artery disease (CAD). Two independent reviewers searched on MEDLINE/EMBASE with the following inclusion criteria: 01/01/2000-03/23/2015 publication date; per-patient sensitivity/specificity for >50% stenosis confirmed by conventional coronary angiography with raw data provided or retrievable; sample size >10. Quality was appraised using QUADAS2. Nine hundred eighteen studies were retrieved, 24 of them, including 1,638 patients, were selected. Using a bivariate model, the pooled sensitivity was 89% (95% confidence interval 86-92%), the pooled specificity 72% (63-79%). Meta-regression did not show a significant impact on sensitivity/specificity for both year of publication and disease prevalence (p ≥ 0.114). Sensitivity of contrast-enhanced examinations (95%, 90-97%) was higher (p = 0.005) than that of unenhanced examinations (87%, 83-90%). Specificity of whole-heart acquisition mode (78%, 72-84%) was higher (p = 0.006) than that of targeted mode (57%, 45-69%). Specificity at 3T (83%, 69-92%) was higher (p = 0.067) than that at 1.5T (68%, 60-76%). Risk of bias and concerns regarding applicability were low. Sensitivity and specificity of MRCA for CAD were 89% and 72%, respectively. A specificity higher than 80% may be obtained at 3T. Whole-heart contrast-enhanced protocols should be preferred for a higher diagnostic performance. • MRCA sensitivity and specificity for CAD are below those of CTA. • Contrast administration increased sensitivity to 95 % (90-97 %), comparable with that of CTA. • Whole-heart mode increased specificity to 78 % (72-84 %), comparable with that of CTA. • Specificity at 3T was borderline-significantly higher (p = 0.067) than at 1.5T. • Whole-heart contrast-enhanced protocols are the best approach for MRCA.

Small animal magnetic resonance imaging: an efficient tool to assess liver volume and intrahepatic vascular anatomy

BackgroundTo develop a noninvasive technique to assess liver volumetry and intrahepatic portal vein anatomy in a mouse model of liver regeneration. Materials and methodsFifty-two C57BL/6 male mice underwent magnetic resonance imaging (MRI) of the liver using a 4.7 T small animal MRI system after no treatment, 70% partial hepatectomy (PH), or selective portal vein embolization. The protocol consisted of the following sequences: three-dimensional–encoded spoiled gradient-echo sequence (repetition time per echo time 15 per 2.7 ms, flip angle 20°) for volumetry, and two-dimensional–encoded time-of-flight angiography sequence (repetition time per echo time 18 per 6.4 ms, flip angle 80°) for vessel visualization. Liver volume and portal vein segmentation was performed using a dedicated postprocessing software. In animals with portal vein embolization, portography served as reference standard. True liver volume was measured after sacrificing the animals. Measurements were carried out by two independent observers with subsequent analysis by the Cohen κ-test for interobserver agreement. ResultsMRI liver volumetry highly correlated with the true liver volume measurement using a conventional method in both the untreated liver and the liver remnant after 70% PH with a high interobserver correlation coefficient of 0.94 (95% confidence interval, 0.80–0.98 for untreated liver [P < 0.001] and 0.90–0.97 after 70% PH [P < 0.001]). The diagnostic accuracy of magnetic resonance angiography for the occlusion of one branch of the portal vein was 0.95 (95% confidence interval, 0.84–1). The level of agreement between the two observers for the description of intrahepatic vascular anatomy was excellent (Cohen κ value = 0.925). ConclusionsThis protocol may be used for noninvasive liver volumetry and visualization of portal vein anatomy in mice. It will serve the dynamic study of new strategies to enhance liver regeneration in vivo.

Diagnosing flow residuals in coiled cerebral aneurysms by MR angiography: meta-analysis

This meta-analysis summarizes the accuracy of magnetic resonance angiography (MRA) for diagnosing residuals in coiled cerebral aneurysms by using the threefold Roy classification (residuals: none, neck, or sac). Four databases were searched from 2000 to June 2013 for eligible studies that compared MRA to digital subtraction angiography (DSA) and reported 3 × 3 count data of threefold Roy classification, or a reduced scheme of 2 × 2 count data. Bivariate and trivariate Bayesian random-effects models were used for meta-analysis. Among 27 included studies (2,119 coiled aneurysms in 1,809 patients) the average prevalence of DSA-confirmed sac residuals was 18.2 % (range 0–43 %). The pooled sensitivity was 88.0 % (95 % CI 81.4−94.0) and specificity was 97.2 % (94.6−99.0 %) for assessing sac residuals by MRA. In the trivariate meta-analysis, a “sac residual” finding at MRA had a high positive likelihood ratio of 28.2 (14.0–79.0). A “neck residual” finding had a moderate negative likelihood ratio of 0.246 (0.111–0.426), and the MRA finding of “no residual” had a good negative likelihood ratio of 0.044 (0.013–0.096). Subgroup analyses identified no significant influence of covariates on diagnostic accuracy (P > 0.05). In conclusion, in coiled cerebral aneurysms MRA with application of the threefold Roy classification is well suited for detecting or excluding sac residuals that might require retreatment.Electronic supplementary materialThe online version of this article (doi:10.1007/s00415-013-7053-5) contains supplementary material, which is available to authorized users.

Perforator flap magnetic resonance angiography for reconstructive breast surgery: A review of 25 deep inferior epigastric and gluteal perforator artery flap patients

To evaluate the accuracy of magnetic resonance angiography (MRA) for preoperative mapping of rectus and gluteal muscle perforating arteries prior to autologous flap breast reconstruction. Preoperative MRA on 25 consecutive patients undergoing perforator artery-based autologous breast reconstruction was performed at 1.5 T using 3D liver accelerate volume acquisition (LAVA) of abdominal or gluteal regions acquired during injection of 20 mL of gadobenate dimeglumine with bolus timing optimized using MR fluoroscopy or SmartPrep. Perforator artery size and coordinates relative to umbilicus or top of gluteal crease on 3D MRA were compared to findings at surgery. Reconstructed breast volume estimates from MRA were also compared to weights at harvesting. In all, 132 perforator arteries were found at surgery to be located within 1 cm of the coordinates measured on MRA and were surgically verified to be suitable for flap perfusion. Surgery verified the arterial course and caliber through the rectus and gluteal muscles visualized on MRA in 48 of 49 arteries. Volume rendering of 3D MRA predicted a breast reconstruction volume with a mean difference of 47 g compared to measurements at harvesting. MRA accurately maps rectus and gluteal muscle perforator arteries for preoperative planning of autologous flaps for breast reconstruction.

MRA for Carotid Artery Stenosis

To the Editor: With interest we read the systematic review and meta-analysis on the diagnostic accuracy of magnetic resonance angiography (MRA) in measuring carotid artery stenosis of Debrey and colleagues.1 In this field with rapid technical developments, such as the increasing use of contrast-enhanced MRA (CE-MRA), a pooled estimate of the diagnostic accuracy is timely and useful. The accuracy of this review is however suboptimal, because the largest …

Response to Letter by Nederkoorn and van der Graaf

Response: We appreciate the opportunity to respond to Drs Nederkoorn and van der Graaf in regards to our recent paper entitled “Diagnostic Accuracy of Magnetic Resonance Angiography (MRA) for Internal Carotid Artery Disease: A Systematic Review and Meta-Analysis.”1 In agreement with their statement, we believe that a critical analysis of the existing literature and a pooled estimate of the data are a necessary and beneficial addition to this field. More than 11 000 abstracts were screened for the selection of potential articles to be included in this meta-analysis, which investigated the diagnostic accuracy of both time-of-flight (TOF) MRA and contrast-enhanced (CE) MRA. Of these abstracts, a total of 96 articles were selected for thorough examination. Of these 96, Drs Nederkoorn and van der Graaf, along with their colleagues, had published 3 articles in the period of 2002 to 2003 addressing this issue.2–4 Though it is not stated in any of the three papers that similar data involving an overlap of study …

Accuracy of Magnetic Resonance Angiography for Internal Carotid Artery Disease

HomeStrokeVol. 40, No. 1Accuracy of Magnetic Resonance Angiography for Internal Carotid Artery Disease Free AccessLetterPDF/EPUBAboutView PDFView EPUBSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessLetterPDF/EPUBAccuracy of Magnetic Resonance Angiography for Internal Carotid Artery Disease Marco Oliveira Py Charles André Marco Oliveira PyMarco Oliveira Py Instituto de Neurologia Deolindo Couto/Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil Search for more papers by this author Charles AndréCharles André Hospital Universitário Clementino Fraga Filho/Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil Search for more papers by this author Originally published26 Nov 2008https://doi.org/10.1161/STROKEAHA.108.536177Stroke. 2009;40:e1Other version(s) of this articleYou are viewing the most recent version of this article. Previous versions: November 26, 2008: Previous Version 1 To the Editor:We read with great interest the article entitled “Diagnostic accuracy of magnetic resonance angiography for internal carotid artery disease: a systematic review and meta-analysis.”1 The authors made a comprehensive review and meta-analysis of many articles which compared magnetic resonance angiography (MRA) and digital angiography (DGA), considered the gold standard to study carotid stenosis.As a contribution, although not cited by the authors, we published an article in 20012 about this theme. We compared, in a prospective longitudinal study, 20 internal carotid arteries (ICA) in 10 patients with symptomatic stenosis submitted to screening carotid Doppler studies. Six patients had transient ischemic attacks and 4 had mild strokes. Subjects with 70% or tighter stenosis in this first evaluation were submitted to another carotid duplex scan, bidimensional time-of-flight MRA and DGA, in order to compare these diagnostic methods. We used the NASCET3 method to measure ICA stenosis, and we considered DGA as the gold standard. Each diagnostic procedure was independently evaluated by the participating physicians, who were blind to the results of other tests.We found an excellent correlation between the methods when we divided our sample in surgical (70% to 99% stenosis) and nonsurgical patients. Sensitivity (95% CI) for detecting ‘surgical patients’ (70% to 99% stenosis) was 100% (39.6% to 100%) for both duplex scan and bidimensional time-of-flight MRA, compared to DGA, and specificity was 93.8% (67.7% to 99.7%) and 75% (47.4% to 91.7%) respectively. Positive predictive value (95% CI) was 80% (29.9% to 98.9%) for duplex scan and 50% (17.4% to 82.6%) for MRA. Negative predictive value (95% CI) was 100% (74.7% to 100%) and 100% (69.9% to 100%) respectively.2Because of our small sample size, confidence intervals were large, but results are similar to those found in the meta-analysis by Debrey et al.1 A previous meta-analysis4 found different results with 82% to 86% sensitivity and 98% specificity for duplex scan and MRA cases with total ICA occlusion. In stenosis ≥70%, sensitivity ranged from 83% to 86% and specificity ranged from 89% to 94%.Differentiation between ICA subocclusion and total occlusion proved difficult with MRA alone, but could be accurately done by analyzing the combined results of duplex scan and MRA.2In conclusion, combining duplex scan and MRA results may prove more dependable than using MRA alone; when both methods are concordant, they may safely substitute invasive DGA.DisclosuresNone.1 Debrey SM, Yu H, Lynch JK, Lövblad KO, Wright VL, Janket SJD, Baird AE. Diagnostic accuracy of magnetic resonance angiography for internal carotid artery disease: a systematic review and meta-analysis. Stroke. 2008; 39: 2237–2248.LinkGoogle Scholar2 Py MO, André C, Azevedo FS, Domingues RC, Salomão RF. Internal carotid artery stenosis: comparison of duplex scan and magnetic resonance angiography with digital subtraction angiography. Arq Neuropsiquiatr. 2001; 59: 665–671.CrossrefMedlineGoogle Scholar3 North American Symptomatic Carotid Endarterectomy Trial Collaborators. Beneficial effect of carotid endarterectomy in symptomatic patients with high-grade carotid stenosis. N Engl J Med. 1991; 325: 445–53.CrossrefMedlineGoogle Scholar4 Blakeley DD, Oddone EZ, Hasselblad V, Simel DL, Matchar DB. Noninvasive carotid artery testing: a meta-analytic review. Ann Intern Med. 1995; 122: 360–367.CrossrefMedlineGoogle Scholar Previous Back to top Next FiguresReferencesRelatedDetails January 2009Vol 40, Issue 1 Advertisement Article InformationMetrics https://doi.org/10.1161/STROKEAHA.108.536177PMID: 19038909 Originally publishedNovember 26, 2008 PDF download Advertisement

Diagnostic Accuracy of Magnetic Resonance Angiography for Internal Carotid Artery Disease

Accurate diagnosis of the degree of internal carotid artery (ICA) stenosis is needed for decisions regarding optimal stroke prevention. Noninvasive magnetic resonance angiography (MRA) is being proposed and used as a replacement for the gold standard, intra-arterial angiography. Our purpose was to perform a systematic review and diagnostic meta-analysis to determine the sensitivity and specificity of time-of-flight (TOF) MRA and contrast-enhanced (CE) MRA for the detection of (1) high-grade (> or = 70% to 99%) ICA stenoses; (2) ICA occlusions; (3) moderately severe (50% to 69%) ICA stenoses; and (4) compare the overall accuracy of the 2 MRA techniques. The medical literature on MRA and the diagnosis of ICA steno-occlusive disease was reviewed through the PubMed, EMBASE, and SCOPUS databases. All publication years were included through to November 2006. Studies were eligible for inclusion if they compared the accuracy of TOF or CE MRA for the detection of ICA disease against intra-arterial angiography and reported sufficient data. The overall sensitivity of TOF MRA for the detection of > or = 70% to 99% ICA stenoses was 91.2% (95% CI: 88.9% to 93.1%) with a specificity of 88.3% (86.7% to 89.7%), whereas the sensitivity of CE MRA was 94.6% (92.4% to 96.4%) with a specificity of 91.9% (90.3% to 93.4%). For the detection of ICA occlusions, the sensitivity of TOF MRA was 94.5% (91.2% to 96.8%) and the specificity was 99.3% (98.9% to 99.6%), whereas the sensitivity and specificity values for CE MRA were 99.4% (96.8% to 100%) and 99.6% (99.2% to 99.9%), respectively. For moderately severe (50% to 69%) stenoses, TOF MRA had a sensitivity of only 37.9% (29.3% to 47.1%) and a specificity of 92.1% (89.6% to 94.1%); for CE MRA, the pooled sensitivity value was somewhat better at 65.9% (57.0% to 74.0%), whereas the specificity was 93.5% (91.3% to 95.3%). TOF MRA and CE MRA showed high accuracy for the detection of high-grade ICA stenoses and occlusions with CE MRA having the edge over TOF MRA, but had only poor (TOF MRA) to fair (CE MRA) sensitivity for the detection of moderately severe stenoses.

Clinical Study and Comparison of Magnetic Resonance Angiography (MRA) and Angiography Diagnosis of Blunt Vertebral Artery Injury

Two-dimensional time-of-flight (2D TOF) magnetic resonance angiography (MRA) is the major method for detecting vertebral artery injury (VAI). But there is still controversy over MRA's accuracy in detecting VAI of varying degrees, a technique for which there are no animal studies found in the literature. The purpose of this study was to evaluate the value of MRA for detecting vertebral artery injury in cervical spinal trauma patients and to conduct a comparative study of MRA and angiography of blunt vertebral artery injury in an animal experiment. In clinical study, 319 patients with close cervical spinal trauma underwent 2D TOF MRA prospective examination. The strike-induced flexion injury model of the cervical spine was constructed based on animal experiment with 14 adult dogs. X-ray studies were performed immediately after injury. 2D TOF MRA and angiography were formed within 24 to 36 hours. Vertebral artery injury was detected by 2D TOF MRA in 52 of the 319 patients. Of the 52 patients, there were 51 unilateral vertebral artery injuries, including 22 injuries on the left vertebral artery and 29 on the right vertebral artery. One patient sustained bilateral vertebral artery injury. Seven dogs had unilateral VAI (5 on the left, 2 on the right), and two dogs had narrower-than-normal left vertebral arteries on MRA examination. Angiography showed occlusion exactly in seven dogs with unilateral vertebral artery injury detected by MRA and no abnormal findings were detected in five dogs without vertebral artery injury on MRA. In two dogs with incomplete left vertebral artery flow-related enhancement on MRA, angiography showed occlusion in one dog and no vertebral injury with normal image in the other. 2D TOF MRA is an effective detection method of blunt vertebral artery injury but it might not be able to differentiate spasm, a small disruption of intima, from others under certain conditions.

Detection and Localization in Test Accuracy: A Bayesian Perspective

In assessing the area under the ROC curve for the accuracy of a diagnostic test, it is imperative to detect and locate multiple abnormalities per image. This approach takes that into account by adopting a statistical model that allows for correlation between the reader scores of several regions of interest (ROI). The ROI method of partitioning the image is taken. The readers give a score to each ROI in the image and the statistical model takes into account the correlation between the scores of the ROI's of an image in estimating test accuracy. The test accuracy is given by Pr[Y > Z] + (1/2)Pr[Y = Z], where Y is an ordinal diagnostic measurement of an affected ROI, and Z is the diagnostic measurement of an unaffected ROI. This way of measuring test accuracy is equivalent to the area under the ROC curve. The parameters are the parameters of a multinomial distribution, then based on the multinomial distribution, a Bayesian method of inference is adopted for estimating the test accuracy. Using a multinomial model for the test results, a Bayesian method based on the predictive distribution of future diagnostic scores is employed to find the test accuracy. By resampling from the posterior distribution of the model parameters, samples from the posterior distribution of test accuracy are also generated. Using these samples, the posterior mean, standard deviation, and credible intervals are calculated in order to estimate the area under the ROC curve. This approach is illustrated by estimating the area under the ROC curve for a study of the diagnostic accuracy of magnetic resonance angiography for diagnosis of arterial atherosclerotic stenosis. A generalization to multiple readers and/or modalities is proposed. A Bayesian way to estimate test accuracy is easy to perform with standard software packages and has the advantage of employing the efficient inclusion of information from prior related imaging studies.

Living related liver transplantation: preoperative magnetic resonance imaging for assessment of hepatic vasculature of donor candidates

To evaluate the accuracy of magnetic resonance angiography (MRA) for preoperative assessment of hepatic vascular anatomy in liver donors before living related liver transplantation. A total of 55 consecutive living liver donors (mean age 42 years, range 18-68 years) underwent multiphase contrast-enhanced MRA of the hepatic vessels. Two readers categorized vessel visualization on a five-point scale and recorded vascular anatomy or variations thereof for the arterial, portal venous and venous systems. All 55 living liver donors subsequently underwent right hemihepatectomy for hemiliver donation, and preoperative MRA results were correlated with surgical findings. Overall vessel visualization assessment demonstrated good or very good ratings for the majority of patients. For hepatic arteries, the mean score was 4.4+/-0.8 (mean+/-standard deviation), and for the portal venous and venous systems it was 4.6+/-0.7 and 4.3+/-0.8, respectively. Among all 55 donors, 16 (29%) demonstrated accessory or replaced hepatic arteries, and seven (13%) and 20 (36%) donors had surgically relevant portal vein (trifurcation or early right posterolateral branching types) and hepatic vein variations, respectively. Correlation coefficients between MRA and surgery were 0.94, 1.00 and 0.91 for hepatic arteries, portal veins and hepatic veins, respectively. In the preoperative evaluation before living related liver donation, contrast-enhanced MR angiography was a highly accurate, noninvasive tool for visualizing the hepatic vasculature and variations thereof in liver donor candidates.