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PURPOSE: To develop a method that achieves simultaneous brain and neck time-of-flight (ToF) magnetic resonance angiography (MRA) within feasible scan timeframes. METHODS: Localized quadratic (LQ) encoding is efficient for both signal-to-noise ratio (SNR) and in-flow enhancement. We proposed a spiral multiband LQ method to enable simultaneous intracranial and carotid ToF-MRA within a single scan. To address the venous signal contamination that becomes a challenge with multiband (MB) ToF, tilt-optimized non-saturated excitation (TONE) and partial-Fourier slice selection (PFSS) were further introduced in the LQ framework to mitigate the venous signal and improve artery contrast. A sequential spiral MB and LQ reconstruction pipeline was employed to obtain the brain-and-neck image volumes. RESULTS: The proposed MB method was able to achieve simultaneous brain and neck ToF-MRA within a 2:50-min scan. The complementarily boosted SNR-efficiency by MB and LQ acquisitions allows for the increased spatial coverage without increase in scan time or noticeable compromise in SNR. The incorporation of both TONE and PFSS effectively alleviated the venous contamination with improved small vessel sensitivity. Selection of scan parameters such as the LQ factor and flip angle reflected the trade-off among SNR, blood contrast, and venous suppression. CONCLUSIONS: A novel MB spiral LQ approach was proposed to enable fast intracranial and carotid ToF-MRA with minimized venous corruption. The method has shown promise in MRA applications where large spatial coverage is necessary.

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Objective: Evaluation of intracranial stent placement by MRI suffers the problems of signal artifacts during time-of-flight MRA (TOF-MRA). Therefore, angiographic examination is required for detailed intravascular assessment of the stent placement site. Recently, 3D T1-turbo spin echo (3D-TSE) has been developed for evaluation of carotid artery stent placement. We investigated the use of the 3D-TSE imaging method for the evaluation of intracranial vascular stent placement. Methods: The subjects consisted of nine patients who underwent intracranial vascular stent placement between April 2015 and December 2019. Postoperatively, the lumens of the placed stents were measured by TOF-MRA, DSA, and 3D-TSE imaging. Analysis was performed by type of stent and placement site. Results: The stents used were Neuroform Atlas (3 patients), LVIS (3 patients), LVIS Jr (2 patients), and Integrity (1 patient). TOF-MRA of the stent placement site showed defects in the image or poor visualization in all nine patients, whereas 3D-TSE imaging visualized the lumen at the stent indwelling site in all patients. The blood vessel diameter measured by the DSA and 3D-TSE imaging exhibited positive correlations regardless of the stent type and placement site. Conclusion: 3D-TSE imaging allows visualization of the lumen of the site of an intracranial vascular stent, regardless of the type of stent or the vessel. Thus, this method may be useful for evaluating the vascular lumen of a lesion.

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Background: Neurosurgical resection of insular gliomas is complicated by the possibility of iatrogenic injury to the lenticulostriate arteries (LSAs) and is associated with devastating neurological complications, hence the need to accurately assess the number of LSAs and their relationship to the tumor preoperatively. Methods: The study included 24 patients with insular gliomas who underwent preoperative 3D-TOF MRA to visualize LSAs. The agreement of preoperative magnetic resonance imaging with intraoperative data in terms of the number of LSAs and their invasion by the tumor was assessed using the Kendall rank correlation coefficient and Cohen's Kappa with linear weighting. Agreement between experts performing image analysis was estimated using Cohen's Kappa with linear weighting. Results: The number of LSAs arising from the M1 segment varied from 0 to 9 (mean 4.3 â€‹± â€‹0.37) as determined by 3D-TOF MRA and 2-6 (mean 4.25 â€‹± â€‹0.25) as determined intraoperatively, κ â€‹= â€‹0.51 (95% CI: 0.25-0.76) and τ â€‹= â€‹0.64 (p â€‹< â€‹0.001). LSAs were encased by the tumor in 11 patients (confirmed intraoperatively in 9 patients). LSAs were displaced medially in 8 patients (confirmed intraoperatively in 8 patients). The tumor partially involved the LSAs and displaced them in 5 patients (confirmed intraoperatively in 7 patients), κ â€‹= â€‹0.87 (95% CI: 0.70-1), τ â€‹= â€‹0.93 (p â€‹< â€‹0.001). 3D-TOF MRA demonstrated high sensitivity (100%, 95% CI: 0.63-1) and high specificity (86.67%, 95% CI: 0.58-0.98) in determining the LSA-tumor interface. Conclusions: 3D-TOF MRA at 3T demonstrated sensitivity in determining the LSA-tumor interface and the number of LSAs in patients with insular gliomas.

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PURPOSE: 3D time-of-flight MRA can accurately visualize the intracranial vasculature but is limited by long acquisition times. Compressed sensing reconstruction can be used to substantially accelerate acquisitions. The quality of those reconstructions depends on the undersampling patterns used. In this work, we optimize sets of undersampling parameters for various acceleration factors of Cartesian 3D time-of-flight MRA. METHODS: Fully sampled datasets, acquired at 7 Tesla, were retrospectively undersampled using variable-density Poisson disk sampling with various autocalibration region sizes, polynomial orders, and acceleration factors. The accuracy of reconstructions from the different undersampled datasets was assessed using the vessel-masked structural similarity index. Identified optimal undersampling parameters were then evaluated in additional prospectively undersampled datasets. Compressed sensing reconstruction parameters were chosen based on a preliminary reconstruction parameter optimization. RESULTS: For all acceleration factors, using a fully sampled calibration area of 12 × 12 k-space lines and a polynomial order of 2 resulted in the highest image quality. The importance of parameter optimization of the sampling was found to increase for higher acceleration factors. The results were consistent across resolutions and regions of interest with vessels of varying sizes and tortuosity. The number of visible small vessels increased by 7.0% and 14.2% when compared to standard parameters for acceleration factors of 7.2 and 15, respectively. CONCLUSION: The image quality of compressed sensing time-of-flight MRA can be improved by appropriate choice of undersampling parameters. The optimized sets of parameters are independent of the acceleration factor and enable a larger number of vessels to be visualized.

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BACKGROUND: Nonenhanced MR angiography (MRA) studies are often used to manage acute and chronic large cervical artery disease, but lengthy scan times limit their clinical usefulness. PURPOSE: To develop an accelerated cervical MRA and test its diagnostic performance. STUDY TYPE: Prospective. POPULATION: Patients with cervical artery disease (n = 32, 17 males). FIELD STRENGTH/SEQUENCE: 3.0 T; accelerated two-point Dixon three-dimensional Cartesian spoiled gradient-echo (FLEXA) and conventional time-of-flight MRA (cMRA) sequences. ASSESSMENT: All patients underwent FLEXA (1'28″) and cMRA (6'47″) acquisitions. Quantitative evaluation (artery-to-background signal ratio and a blur metric) and qualitative evaluation using diagnostic performance measured by the sensitivity, specificity, and positive/negative predictive values (PPV/NPV), and vessel and plaque visualization scores from three board-certified radiologists' (with 10, 11, and 12 years of experience) independent readings using maximum intensity projection (MIP) for luminal diseases and axial images for plaque. The reference standards were contrast-enhanced angiography and fat-saturated T1-weighted images, respectively. STATISTICAL TESTS: All measures were compared between FLEXA and cMRA using the paired t, Wilcoxon signed-rank, McNemar's, or chi-squared test, as appropriate. Interreader agreement was assessed using Cohen's κ. P < 0.05 was considered statistically significant. RESULTS: The artery-to-background signal ratio was significantly higher for FLEXA (FLEXA: 7.20 ± 1.63 [fat]; 4.26 ± 0.52 [muscle]; cMRA: 2.57 ± 0.49 [fat]), while image blurring was significantly less (FLEXA: 0.24 ± 0.016; cMRA: 0.30 ± 0.029). In luminal disease detection, sensitivity (FLEXA: 0.97/0.91/0.91; cMRA:0.71/0.69/0.63), specificity (FLEXA: 0.98/0.93/0.98; cMRA:0.93/0.85/0.92), PPV (FLEXA: 0.92/0.86/0.86; cMRA: 0.64/0.5/0.58), and NPV (FLEXA: 0.99/0.98/0.98; cMRA: 0.92/0.91/0.9) were significantly higher for FLEXA. interreader agreement was substantial to almost perfect for FLEXA (κ = 0.82/0.86/0.78) and moderate to substantial for cMRA (κ = 0.67/0.56/0.57). MIP visualization scores were significantly higher for FLEXA, with substantial to almost perfect interreader agreement (FLEXA: κ = 0.83/0.86/0.82; cMRA: κ = 0.89/0.79/0.79). In plaque detection, sensitivity (FLEXA: 0.9/0.9/0.7; cMRA: 0.3/0.6/0.2) and specificity (FLEXA: 1/0.87/1; cMRA: 0.93/0.63/0.97) were significantly higher for FLEXA in two of three readers. The interreader plaque detection agreement was fair to substantial (FLEXA: κ = 0.63/0.69/0.48; cMRA: κ = 0.21/0.45/0.20). Side-by-side plaque and vessel wall visualization was superior for FLEXA in all readers, with moderate to substantial interreader agreement (plaque: κ = 0.73/0.73/0.77; vessel wall: κ = 0.57/0.40/0.39). DATA CONCLUSION: FLEXA enhanced visualization of the cervical arterial system and improved diagnostic performance for luminal abnormalities and plaques in patients with cervical artery diseases. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

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OBJECTIVE: To determine the usefulness of Silent MR angiography (MRA) for evaluating intracranial aneurysms treated with stent-assisted coil embolization. MATERIALS AND METHODS: Ninety-nine patients (101 aneurysms) treated with stent-assisted coil embolization (Neuroform atlas, 71 cases; Enterprise, 17; LVIS Jr, 9; and Solitaire AB, 4 cases) underwent time-of-flight (TOF) MRA and Silent MRA in the same session using a 3T MRI system within 24 hours of embolization. Two radiologists independently interpreted both MRA images retrospectively and rated the image quality using a 5-point Likert scale. The image quality and diagnostic accuracy of the two modalities in the detection of aneurysm occlusion were further compared based on the stent design and the site of aneurysm. RESULTS: The average image quality scores of the Silent MRA and TOF MRA were 4.38 ± 0.83 and 2.78 ± 1.04, respectively (p < 0.001), with an almost perfect interobserver agreement. Silent MRA had a significantly higher image quality score than TOF MRA at the distal internal carotid artery (n = 57, 4.25 ± 0.91 vs. 3.05 ± 1.16, p < 0.001), middle cerebral artery (n = 21, 4.57 ± 0.75 vs. 2.19 ± 0.68, p < 0.001), anterior cerebral artery (n = 13, 4.54 ± 0.66 vs. 2.46 ± 0.66, p < 0.001), and posterior circulation artery (n = 10, 4.50 ± 0.71 vs. 2.90 ± 0.74, p = 0.013). Silent MRA had superior image quality score to TOF MRA in the stented arteries when using Neuroform atlas (4.66 ± 0.53 vs. 3.21 ± 0.84, p < 0.001), Enterprise (3.29 ± 1.59 vs. 1.59 ± 0.51, p = 0.003), LVIS Jr (4.33 ± 1.89 vs. 1.89 ± 0.78, p = 0.033), and Solitaire AB stents (4.00 ± 2.25 vs. 2.25 ± 0.96, p = 0.356). The interpretation of the status of aneurysm occlusion exhibited significantly higher sensitivity with Silent MRA than with TOF MRA when using the Neuroform Atlas stent (96.4% vs. 14.3%, respectively, p < 0.001) and LVIS Jr stent (100% vs. 20%, respectively, p = 0.046). CONCLUSION: Silent MRA can be useful to evaluate aneurysms treated with stent-assisted coil embolization, regardless of the aneurysm location and type of stent used.

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Aortic dissection is a rare cause of an acute ischemic stroke or transient ischemic attack (TIA). Aortic dissection is particularly challenging in stroke patients who are eligible for thrombolysis secondary to the diagnostic difficulty within a narrow time window (4.5 h) and have a risk of developing life-threatening hemorrhagic complications following thrombolysis. Computed tomographic angiography (CTA) has been the mainstay of imaging when evaluating acute aortic syndrome. However, it cannot be routinely performed for pregnant patients and those with renal failure or iodine-contrast media allergy. We report a case of a 72-year-old woman who developed transient right-hand paralysis without any chest symptoms. Brain magnetic resonance imaging (MRI) showed no recent infarction; however, the brachiocephalic trunk was not well visualized on carotid magnetic resonance angiography (MRA). Subsequent thoracic pulse-gated noncontrast three-dimensional balanced steady-state free precession MRA (bSSFP-MRA) detected a Stanford type A acute aortic dissection (TAAAD). This was confirmed by CTA, leading to the diagnosis of TIA due to Stanford TAAAD. Pulse-gated noncontrast thoracic bSSFP-MRA was acquired a few minutes after a series of brain MRI scans. This imaging modality is expected to be used as a screening platform to rule out Stanford TAAAD during the hyperacute phase of stroke.

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PURPOSE: To investigate the clinical utility of pointwise encoding time reduction with radial acquisition in subtraction-based magnetic resonance angiography (PETRA-MRA) and time-of-flight magnetic resonance angiography (TOF-MRA) to evaluate saccular unruptured intracranial aneurysms (UIAs). METHODS: A total of 49 patients with 54 TOF-MRA-identified saccular UIAs were enrolled. The morphologic parameters, contrast-to-noise-ratios (CNRs), and sharpness of aneurysms were measured using PETRA-MRA and TOF-MRA. Two radiologists independently evaluated subjective image scores, focusing on aneurysm signal homogeneities and sharpness depictions using a 4-point scale: 4, excellent; 3, good; 2, poor; 1, not assessable. PETRA-MRA and TOF-MRA acoustic noises were measured. RESULTS: All aneurysms were detected with PETRA-MRA. The morphologic parameters of 15 patients evaluated with PETRA-MRA were more closely correlated with those receiving computed tomography angiography over those receiving TOF-MRA. No significant differences between PETRA-MRA and TOF-MRA parameters were seen in the 54 UIAs (p > 0.10), excluding those with inflow angles (p < 0.05). In four patients with inflow angles on PETRA-MRA, the angles were more closely related to those of digital subtraction angiography than those of TOF-MRA. CNRs between TOF-MRA and PETRA-MRA were comparable (p = 0.068), and PETRA-MRA sharpness values and subjective image scores were significantly higher than those of TOF-MRA (p < 0.001). Inter-observer agreements were excellent for both PETRA-MRA and TOF-MRA (intraclass correlation coefficients were 0.90 and 0.97, respectively). The acoustic noise levels of PETRA-MRA were much lower than those of TOF-MRA (59 vs.73 dB, p < 0.01). CONCLUSIONS: PETRA-MRA, with better visualization of aneurysms and lower acoustic noise levels than TOF-MRA, showed a superior diagnostic performance for depicting saccular UIAs.

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BACKGROUND: Noninvasive assessment of intracranial stenosis is important to manage ischemic stroke patients. However, few previous studies have compared 3D black-blood MRI with 3D time-of-flight (TOF), magnetic resonance angiography (MRA), and digital subtraction angiography (DSA) for intracranial artery plaque assessment. PURPOSE: To compare 3D black-blood MRI and 3D TOF-MRA, using DSA as the reference standard for intracranial stenosis and atherosclerotic plaque assessment in patients with posterior circulation stroke or transient ischemic attacks (TIAs). STUDY TYPE: Prospective, cohort study. POPULATION: One hundred and one patients with posterior circulation stroke and/or TIA (age 63 ± 10 years, 84 male) who underwent DSA and MRI within 4 weeks of each other. FIELD STRENGTH/SEQUENCE: 3D fast-spin-echo MRI for intracranial vessel wall imaging (IVWI) and 3D TOF at 3T. ASSESSMENT: Two radiologists independently measured the degree of stenosis on 3D IVWI and TOF, using DSA as a reference. Plaque enhancement was recorded when the plaque was stenosis-free on DSA. STATISTICAL TESTS: Shapiro-Wilk's test, Student's t-test, Mann-Whitney U-test, Spearman correlation, Bland-Altman analysis, and interclass correlation coefficient (ICC). RESULTS: A total of 238 intracranial plaques (203 posterior, 35 anterior) were included. 3D IVWI showed better agreement with DSA in measuring stenosis than TOF (ICC = 0.89 vs. 0.64). 3D IVWI had higher sensitivity and specificity for detecting stenosis >50% and stenosis >75% than TOF, using DSA as the standard. TOF significantly overestimated the degree of stenosis compared to DSA (65 ± 19% vs. 51 ± 15%, P < 0.001). DSA did not observe 62 nonstenotic plaques (26.1%) that were shown only on 3D IVWI, in which 36 plaques (58.1%) showed contrast enhancement. The interreader agreement for measuring stenosis were excellent, with ICCs >0.90 for all three modalities. DATA CONCLUSION: 3D black-blood MRI is accurate and reproducible for quantifying intracranial artery stenosis compared with DSA, and performs better than 3D TOF. As compared to DSA, it detects more nonstenotic plaques. Level of Evidence 1 Technical Efficacy Stage 2 J. MAGN. RESON. IMAGING 2021;53:469-478.

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OBJECTIVE: The authors conducted a study to noninvasively and nonradioactively reveal moyamoya disease (MMD) intracerebral perfusion and perfusion territory supplied by the unilateral internal carotid artery (ICA) and external carotid artery (ECA) and bilateral vertebral arteries (VAs) before surgery and to further identify risk factors for preoperative hemorrhage in adult MMD. METHODS: Forty-three consecutive adult patients with bilateral MMD underwent unenhanced T1-weighted MRI, territorial arterial spin labeling (t-ASL), and unenhanced 3D time-of-flight MRA (3D-TOF-MRA). Clinical factors, including age, sex, hypertension, diabetes mellitus, hyperlipidemia, current smoking status, and history of taking aspirin, were gathered and stratified. Univariate logistic regression analyses were used to examine the relationship between various risk factors and the occurrence of preoperative hemorrhage. Stepwise multivariate logistic regression analyses were used to determine independent risk factors of preoperative hemorrhage in MMD. RESULTS: Among the 86 MMD hemispheres, t-ASL revealed 137 perfusion territory shifts in 79 hemispheres. Five distinct categories of perfusion territory shifts were observed on t-ASL maps. The subtypes of perfusion territory shift on t-ASL maps were further subdivided into 2 different categories, group A and group B, in combination with findings on 3D-TOF-MRA. A perfusion territory shift attributable solely to the secondary collaterals was a potential independent risk factor for preoperative hemorrhage (p = 0.026; 95% CI 1.201-18.615; OR 4.729). After eliminating the influence of the secondary collaterals, the primary collaterals had no significant effect on the risk of preoperative hemorrhage (p = 0.182). CONCLUSIONS: t-ASL could reveal comprehensive MMD cerebral blood perfusion and the vivid perfusion territory shifts fed by the unilateral ICA and ECA and bilateral VAs in a noninvasive, straightforward, nonradioactive, and nonenhanced manner. 3D-TOF-MRA could subdivide t-ASL perfusion territory shifts according to their shunt arteries. A perfusion territory shift attributable to the secondary collaterals is a potential independent risk factor for preoperative hemorrhage in MMD patients. A perfusion territory shift fed by the primary collaterals may not have a strong effect on preoperative hemorrhage in MMD patients. These findings make the combined modalities of t-ASL and 3D-TOF-MRA a feasible tool for MMD disease assessment, management, and surgical strategy planning.

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PURPOSE: To compare the performance of magnetic resonance angiography (MRA) with 1M gadobutrol, a high relaxivity macrocyclic contrast agent, to 2D time-of-flight MRA (ToF-MRA) using computed tomographic angiography (CTA) as the standard of reference. Primary objectives were evaluation for superiority of structural delineation and noninferiority for detection and exclusion of clinically significant disease. MATERIALS AND METHODS: In all, 315 subjects underwent unenhanced and contrast-enhanced MRA with 1M gadobutrol (CE-MRA) and were scanned with 1.5T MRI equipped with an at least 6-element body coil. Evaluations were based on both centralized blinded read (BR) performed by six readers as well as investigator site interpretations for the 292 subjects who completed the study. Quantitative evaluations including percent stenosis and normal vessel measurements were also performed. Secondary endpoints included identification of accessory renal arteries, diagnosis of fibromuscular dysplasia (FMD), diagnostic confidence, and need for additional imaging. RESULTS: A total of 292 patients suspected of renal artery disease completed the study. CE-MRA demonstrated statistically significant improvement in assessability of vascular segments compared to ToF: 95.9% vs. 77.6% (P < 0.0001). In the BR, the sensitivity and specificity of CE-MRA were noninferior to ToF-MRA (53.4% vs. 46.6% and 95.1% vs. 85.7%, respectively). There was less error in the CE-MRA stenosis measurements (0.15 mm gadobutrol vs. 0.41 mm ToF, P < 0.05). FMD was correctly diagnosed more frequently, 10% more accessory renal arteries were identified (P < 0.01), diagnostic confidence increased (P < 0.01), and fewer additional imaging studies were recommended (P < 0.01). CONCLUSION: Gadobutrol-enhanced MRA of the renal arteries has superior visualization, more accurate vessel measurements, and may serve as a CTA alternative without any ionizing radiation. LEVEL OF EVIDENCE: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:572-581.

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OBJECTIVE: The differentiation between an aneurysm and an infundibulum with time-of-flight MRA is often difficult. However, this distinction is important because it affects further patient follow-up. The purpose of this study was to assess the added value of high resolution 7Tesla MRA for investigating small vascular lesions suspect for an aneurysm or an infundibulum. MATERIALS AND METHODS: We included patients in whom an intracranial vascular lesion was detected in our University Hospital and in whom the discrimination between a true aneurysms or an infundibulum could not be made on conventional 1.5 or 3T MRI were included in the study. All patients underwent an additional 7T time-of-flight MRA at higher spatial resolution. RESULTS: We included 6 patients. The age range of the patients was 35-65years and 5 of them were women. 1 out of 6 had a 1.5T MRI, the other 5 patients had a 3T MRI previous to the 7T MRI. The lesion size varied between 0.9mm and 2.0mm. In 5 of the 6 patients the presence of an infundibulum could be proven using the high resolution of the 7T MRA. All patients tolerated the 7T MRI well. CONCLUSION: Our results suggest that high resolution and contrast of 7T MRA provides added diagnostic value in discriminating between intracranial aneurysms and infundibula. This finding may have important consequences for patient follow-up and comfort because it might reduce unnecessary follow-up exams and decrease uncertainty about the diagnosis. Larger studies, however, are needed to confirm our findings.

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The aim of this meta-analysis was to evaluate the diagnostic value of 3D time-of-flight magnetic resonance angiography (3D-TOF-MRA) in trigeminal neuralgia (TN). Relevant studies were identified by computerized database searches supplemented by manual search strategies. The studies were included in accordance with stringent inclusion and exclusion criteria. Following a multistep screening process, high quality studies related to the diagnostic value of 3D-TOF-MRA in TN were selected for meta-analysis. Statistical analyses were conducted using Statistical Analysis Software (version 8.2; SAS Institute, Cary, NC, USA) and Meta Disc (version 1.4; Unit of Clinical Biostatistics, Ramon y Cajal Hospital, Madrid, Spain). For the present meta-analysis, we initially retrieved 95 studies from database searches. A total of 13 studies were eventually enrolled containing a combined total of 1084 TN patients. The meta-analysis results demonstrated that the sensitivity and specificity of the diagnostic value of 3D-TOF-MRA in TN were 95% (95% confidence interval [CI] 0.93-0.96) and 77% (95% CI 0.66-0.86), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 2.72 (95% CI 1.81-4.09) and 0.08 (95% CI 0.06-0.12), respectively. The pooled diagnostic odds ratio of 3D-TOF-MRA in TN was 52.92 (95% CI 26.39-106.11), and the corresponding area under the curve in the summary receiver operating characteristic curve based on the 3D-TOF-MRA diagnostic image of observers was 0.9695 (standard error 0.0165). Our results suggest that 3D-TOF-MRA has excellent sensitivity and specificity as a diagnostic tool for TN, and that it can accurately identify neurovascular compression in TN patients.

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Objective To evaluate the application of three dimensional time-of-flight (3D-TOF) MRA in screening intracranial aneurysms in the population of Wenling community. Methods A total of 2 124 patients with suspicious intracranial aneurysm in Wenling community, who received 3D-TOF MRA and three dimensional digital subtraction angiography(3D-DSA) during the period from September 2011 to August 2012, were enrolled in this study. The epidemic data of intracranial aneurysm in Wenling community were analyzed, the effectiveness of 3D-TOF MRA in detecting intracranial aneurysm was assessed, and the consistency between 3D-TOF MRA and 3D-DSA (regarded as the golden standard) in detecting intracranial aneurysm was statistically analyzed. Results The results of 3D-TOF MRA showed that the morbidity of intracranial aneurysm in the population of Wenling community was 6.87% (146/2 124), among which the morbidities in males and females were 48.63% (n=71) and 51.37% (n=75) respectively; the mean age of patients was (41.2±11.6) years old. The accompanying diseases included hypertension, diabetes mellitus, arteriosclerosis and cerebrovascular lesions. 3D-TOF MRA examination revealed 149 intracranial aneurysms, among which misdiagnosis was made in 5 patients and missed diagnosis in 2 patients. The sensitivity, specificity and accuracy of 3D-TOF MRA in diagnosing intracranial aneurysm were 98.63% (144/146), 99.72%(1 773/1 778) and 99.67%(2 117/2 124) respectively. No statistically significant difference in measuring the longitudinal diameter and neck width of intracranial aneurysms existed between 3D-TOF MRA and 3D-DSA examinations (P>0.05). Conclusion In detecting intracranial aneurysm, 3D-TOF MRA carries higher sensitivity, specificity and accuracy, and its non-invasive advantage is more suitable for the screening of intracranial aneurysms.

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PURPOSE: To compare 3T elliptical-centric CE MRA with 3T TOF MRA for the detection and characterization of unruptured intracranial aneurysms (UIAs), by using digital subtracted angiography (DSA) as reference. MATERIALS AND METHODS: Twenty-nine patients (12 male, 17 female; mean age: 62 years) with 41 aneurysms (34 saccular, 7 fusiform; mean diameter: 8.85 mm [range 2.0-26.4mm]) were evaluated with MRA at 3T each underwent 3D TOF-MRA examination without contrast and then a 3D contrast-enhanced (CE-MRA) examination with 0.1mmol/kg bodyweight gadobenate dimeglumine and k-space elliptic mapping (Contrast ENhanced Timing Robust Angiography [CENTRA]). Both TOF and CE-MRA images were used to evaluate morphologic features that impact the risk of rupture and the selection of a treatment. Almost half (20/41) of UIAs were located in the internal carotid artery, 7 in the anterior communicating artery, 9 in the middle cerebral artery and 4 in the vertebro-basilar arterial system. All patients also underwent DSA before or after the MR examination. RESULTS: The CE-MRA results were in all cases consistent with the DSA dataset. No differences were noted between 3D TOF-MRA and CE-MRA concerning the detection and location of the 41 aneurysms or visualization of the parental artery. Differences were apparent concerning the visualization of morphologic features, especially for large aneurysms (>13 mm). An irregular sac shape was demonstrated for 21 aneurysms on CE-MRA but only 13/21 aneurysms on 3D TOF-MRA. Likewise, CE-MRA permitted visualization of an aneurismal neck and calculation of the sac/neck ratio for all 34 aneurysms with a neck demonstrated at DSA. Conversely, a neck was visible for only 24/34 aneurysms at 3D TOF-MRA. 3D CE-MRA detected 15 aneurysms with branches originating from the sac and/or neck, whereas branches were recognized in only 12/15 aneurysms at 3D TOF-MRA. CONCLUSION: For evaluation of intracranial aneurysms at 3T, 3D CE-MRA is superior to 3D TOF-MRA for assessment of sac shape, detection of aneurysmal neck, and visualization of branches originating from the sac or neck itself, if the size of the aneurysm is greater than 13 mm. 3T 3D CE-MRA is as accurate and effective as DSA for the evaluation of UIAs.

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OBJECTIVE: To evaluate the usefulness of time-resolved contrast enhanced magnetic resonance angiography (4D MRA) after stent-assisted coil embolization by comparing it with time of flight (TOF)-MRA. MATERIALS AND METHODS: TOF-MRA and 4D MRA were obtained by 3T MRI in 26 patients treated with stent-assisted coil embolization (Enterprise:Neuroform = 7:19). The qualities of the MRA were rated on a graded scale of 0 to 4. We classified completeness of endovascular treatment into three categories. The degree of quality of visualization of the stented artery was compared between TOF and 4D MRA by the Wilcoxon signed rank test. We used the Mann-Whitney U test for comparing the quality of the visualization of the stented artery according to the stent type in each MRA method. RESULTS: The quality in terms of the visualization of the stented arteries in 4D MRA was significantly superior to that in 3D TOF-MRA, regardless of type of the stent (p < 0.001). The quality of the arteries which were stented with Neuroform was superior to that of the arteries stented with Enterprise in 3D TOF (p < 0.001) and 4D MRA (p = 0.008), respectively. CONCLUSION: 4D MRA provides a higher quality view of the stented parent arteries when compared with TOF.

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OBJECTIVE: To evaluate the usefulness of time-resolved contrast enhanced magnetic resonance angiography (4D MRA) after stent-assisted coil embolization by comparing it with time of flight (TOF)-MRA. MATERIALS AND METHODS: TOF-MRA and 4D MRA were obtained by 3T MRI in 26 patients treated with stent-assisted coil embolization (Enterprise:Neuroform = 7:19). The qualities of the MRA were rated on a graded scale of 0 to 4. We classified completeness of endovascular treatment into three categories. The degree of quality of visualization of the stented artery was compared between TOF and 4D MRA by the Wilcoxon signed rank test. We used the Mann-Whitney U test for comparing the quality of the visualization of the stented artery according to the stent type in each MRA method. RESULTS: The quality in terms of the visualization of the stented arteries in 4D MRA was significantly superior to that in 3D TOF-MRA, regardless of type of the stent (p < 0.001). The quality of the arteries which were stented with Neuroform was superior to that of the arteries stented with Enterprise in 3D TOF (p < 0.001) and 4D MRA (p = 0.008), respectively. CONCLUSION: 4D MRA provides a higher quality view of the stented parent arteries when compared with TOF.

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