Assessment of extracranial-intracranial bypass in Moyamoya disease using 3T time-of-flight MR angiography: Comparison with CT angiography

Background: To evaluate the value of time-of-flight MR angiography (TOF MRA) for the assessment of extracranial-intracranial (EC-IC) bypass in Moyamoya disease in comparison with computed tomography angiography (CTA). Patients and methods: A consecutive series of 23 patients with Moyamoya disease were analyzed retrospectively. Twenty three patients underwent 25 procedures of extracranial-intracranial bypass. Cranial CTA was performed within one week after the surgery to assess bypass patency. Then TOF MRA was scanned within 24 h after CTA on a 3T MRI system. Using 5-point scales (0 = poor to 4 = excellent), two radiologists rated the image quality and vessel integrity of bypass for three segments (extracranial, trepanation, intracranial). Results: Image quality was high in both CTA and TOF MRA (mean quality score 3.84 ± 0.37 and 3.8 ± 0.41), without statistical difference (p = 0.66). Mean scores of TOF MRA with respect to bypass visualization were higher than CTA in the intracranial segment (p = 0.026). No significant difference of bypass visualization regarding the extracranial and trepanation segments was found between TOF MRA and CTA (p = 0.66 and p = 0.34, respectively). For the trepanation segment, TOF MRA showed pseudo lesions in 2 of all 25 cases. Conclusions: 3T TOF MRA, a non-contrast technique not exposing the patients to radiation, proved to be at least equal to CTA for the assessment of EC-IC bypass, and even superior to CTA with respect to the intracranial segment. In addition, readers should be aware of a potential overestimation showing focal pseudo lesions of the bypass at the trepanation segment in TOF MRA.

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Follow-up imaging of clipped intracranial aneurysms with 3-T MRI: comparison between 3D time-of-flight MR angiography and pointwise encoding time reduction with radial acquisition subtraction-based MR angiography

Journal of Neurosurgery ◽

10.3171/2021.7.jns211197 ◽

2021 ◽

pp. 1-6

Author(s):

Jae Ho Kim ◽

Sung Jun Ahn ◽

Mina Park ◽

Yong Bae Kim ◽

Bio Joo ◽

...

Keyword(s):

Image Quality ◽

Mr Angiography ◽

Time Of Flight ◽

Parent Artery ◽

Point Scale ◽

Radial Acquisition ◽

Tof Mra ◽

Time Reduction ◽

Acceptable Image Quality

OBJECTIVE Metallic susceptibility artifact due to implanted clips is a major limitation of using 3D time-of-flight magnetic resonance angiography (TOF-MRA) for follow-up imaging of clipped aneurysms (CAs). The purpose of this study was to compare pointwise encoding time reduction with radial acquisition (PETRA) subtraction-based MRA with TOF-MRA in terms of imaging quality and visibility of clip-adjacent arteries for use in follow-up imaging of CAs. METHODS Sixty-two patients with 73 CAs were included retrospectively in this comparative study. All patients underwent PETRA-MRA after TOF-MRA performed simultaneously with 3-T MRI between September 2019 and March 2020. Two neuroradiologists independently compared images obtained with both MRA modalities to evaluate overall image quality using a 4-point scale and visibility of the parent artery and branching vessels near the clips using a 3-point scale. Subgroup analysis was performed according to the number of clips (less-clipped [1–2 clips] vs more-clipped [≥ 3 clips] aneurysms). The ability to detect aneurysm recurrence was also assessed. RESULTS Compared with TOF-MRA, PETRA-MRA showed acceptable image quality (score of 3.97 ± 0.18 for TOF-MRA vs 3.73 ± 0.53 for PETRA-MRA) and had greater visibility of the adjacent vessels near the CAs (score of 1.25 ± 0.59 for TOF-MRA vs 2.27 ± 0.75 for PETRA-MRA, p < 0.0001). PETRA-MRA had greater visibility of vessels adjacent to less-clipped aneurysms (score of 2.39 ± 0.75 for less-clipped aneurysms vs 2.09 ± 0.72 for more-clipped aneurysms, p = 0.014). Of 73 CAs, aneurysm recurrence in 4 cases was detected using PETRA-MRA. CONCLUSIONS This study demonstrated that PETRA-MRA is superior to TOF-MRA for visualizing adjacent vessels near clips and can be an advantageous alternative to TOF-MRA for follow-up imaging of CAs.

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Intralateral and Perilateral Ventricular Arteries on Original Axial Magnetic Resonance Angiography in Adult Moyamoya Disease

European Neurology ◽

10.1159/000514429 ◽

2021 ◽

Vol 84 (2) ◽

pp. 119-123

Author(s):

Mami Ishikawa ◽

Satoshi Terao ◽

Hiroshi Kagami ◽

Makoto Inaba ◽

Heiji Naritaka

Keyword(s):

Magnetic Resonance ◽

Magnetic Resonance Angiography ◽

Cerebral Infarction ◽

Moyamoya Disease ◽

Disease Onset ◽

Time Of Flight ◽

Unruptured Aneurysms ◽

Tof Mra ◽

Adult Moyamoya Disease

Background: Patients with moyamoya disease often develop cerebral infarction and hemorrhage, but the ischemic and hemorrhagic subtypes are difficult to diagnose prior to disease onset. We aimed to differentiate the ischemic and hemorrhagic subtypes of moyamoya disease by analyzing the intralateral and perilateral ventricular arteries on the original axial magnetic resonance angiography (MRA) images. Methods: We retrospectively analyzed the intralateral and perilateral ventricular arteries on the original axial time-of-flight (TOF)-MRA images of 18 patients with hemorrhagic moyamoya disease, 25 patients with ischemic moyamoya disease, and 22 control patients with unruptured aneurysms. Results: There were significantly more intralateral and perilateral ventricular arteries on the original axial MRA images in the patients with hemorrhagic moyamoya disease (6.3 ± 2.7) than in those with ischemic moyamoya disease (0.8 ± 0.9) and those with unruptured aneurysms (0.4 ± 0.8). Conclusion: The intralateral and perilateral ventricular arteries on the original axial TOF-MRA images might suggest the hemorrhagic type of moyamoya disease prior to onset.

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Minimizing table time in patients with claustrophobia using focused ferumoxytol-enhanced MR angiography (f-FEMRA): a feasibility study

British Journal of Radiology ◽

10.1259/bjr.20210430 ◽

2021 ◽

Vol 94 (1125) ◽

pp. 20210430

Author(s):

Puja Shahrouki ◽

Kim-Lien Nguyen ◽

John M. Moriarty ◽

Adam N. Plotnik ◽

Takegawa Yoshida ◽

...

Keyword(s):

Image Quality ◽

Mr Angiography ◽

Signal To Noise Ratio ◽

Diagnostic Image Quality ◽

Diagnostic Confidence ◽

Motion Artefact ◽

Scan Time ◽

Wilcoxon Rank Sum Test ◽

Significant Difference ◽

Noise Ratio

Objectives: To assess the feasibility of a rapid, focused ferumoxytol-enhanced MR angiography (f-FEMRA) protocol in patients with claustrophobia. Methods: In this retrospective study, 13 patients with claustrophobia expressed reluctance to undergo conventional MR angiography, but agreed to a trial of up to 10 min in the scanner bore and underwent f-FEMRA. Thirteen matched control patients who underwent gadolinium-enhanced MR angiography (GEMRA) were identified for comparison of diagnostic image quality. For f-FEMRA, the time from localizer image acquisition to completion of the angiographic acquisition was measured. Two radiologists independently scored images on both f-FEMRA and GEMRA for arterial and venous image quality, motion artefact and diagnostic confidence using a 5-point scale, five being best. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) in the aorta and IVC were measured. The Wilcoxon rank-sum test, one-way ANOVA with Tukey correction and two-tailed t tests were utilized for statistical analyses. Results: All scans were diagnostic and assessed with high confidence (scores ≥ 4). Average scan time for f-FEMRA was 6.27 min (range 3.56 to 10.12 min), with no significant difference between f-FEMRA and GEMRA in diagnostic confidence (4.86 ± 0.24 vs 4.69 ± 0.25, p = 0.13), arterial image quality (4.62 ± 0.57 vs 4.65 ± 0.49, p = 0.78) and motion artefact score (4.58 ± 0.49 vs 4.58 ± 0.28, p > 0.99). f-FEMRA scored significantly better for venous image quality than GEMRA (4.62 ± 0.42 vs 4.19 ± 0.56, p = 0.04). CNR in the IVC was significantly higher for steady-state f-FEMRA than GEMRA regardless of the enhancement phase (p < 0.05). Conclusions: Comprehensive vascular MR imaging of the thorax, abdomen and pelvis can be completed in as little as 5 min within the magnet bore using f-FEMRA, facilitating acceptance by patients with claustrophobia and streamlining workflow. Advances in knowledge: A focused approach to vascular imaging with ferumoxytol can be performed in patients with claustrophobia, limiting time in the magnet bore to 10 min or less, while acquiring fully diagnostic images of the thorax, abdomen and pelvis.

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The Use of Pointwise Encoding Time Reduction With Radial Acquisition MRA to Assess Middle Cerebral Artery Stenosis Pre- and Post-stent Angioplasty: Comparison With 3D Time-of-Flight MRA and DSA

Frontiers in Cardiovascular Medicine ◽

10.3389/fcvm.2021.739332 ◽

2021 ◽

Vol 8 ◽

Author(s):

Feifei Zhang ◽

Yuncai Ran ◽

Ming Zhu ◽

Xiaowen Lei ◽

Junxia Niu ◽

...

Keyword(s):

Magnetic Resonance ◽

Image Quality ◽

Magnetic Resonance Angiography ◽

Flow Visualization ◽

Middle Cerebral Artery ◽

Cerebral Artery ◽

Time Of Flight ◽

Intervention Evaluation ◽

Tof Mra ◽

Angioplasty And Stenting

Background and Purpose: 3D pointwise encoding time reduction magnetic resonance angiography (PETRA-MRA) is a promising non-contrast magnetic resonance angiography (MRA) technique for intracranial stenosis assessment but it has not been adequately validated against digital subtraction angiography (DSA) relative to 3D-time-of-flight (3D-TOF) MRA. The aim of this study was to compare PETRA-MRA and 3D-TOF-MRA using DSA as the reference standard for intracranial stenosis assessment before and after angioplasty and stenting in patients with middle cerebral artery (MCA) stenosis.Materials and Methods: Sixty-two patients with MCA stenosis (age 53 ± 12 years, 43 males) underwent MRA and DSA within a week for pre-intervention evaluation and 32 of them had intracranial angioplasty and stenting performed. The MRAs' image quality, flow visualization within the stents, and susceptibility artifact were graded on a 1–4 scale (1 = poor, 4 = excellent) independently by three radiologists. The degree of stenosis was measured by two radiologists independently on DSA and MRAs.Results: There was an excellent inter-observer agreement for stenosis assessment on PETRA-MRA, 3D-TOF-MRA, and DSA (ICCs > 0.90). For pre-intervention evaluation, PETRA-MRA had better image quality than 3D-TOF-MRA (3.87 ± 0.34 vs. 3.38 ± 0.65, P < 0.001), and PETRA-MRA had better agreement with DSA for stenosis measurements compared to 3D-TOF-MRA (r = 0.96 vs. r = 0.85). For post-intervention evaluation, PETRA-MRA had better image quality than 3D-TOF-MRA for in-stent flow visualization and susceptibility artifacts (3.34 ± 0.60 vs. 1.50 ± 0.76, P < 0.001; 3.31 ± 0.64 vs. 1.41 ± 0.61, P < 0.001, respectively), and better agreement with DSA for stenosis measurements than 3D-TOF-MRA (r = 0.90 vs. r = 0.26). 3D-TOF-MRA significantly overestimated the stenosis post-stenting compared to DSA (84.9 ± 19.7 vs. 39.3 ± 13.6%, p < 0.001) while PETRA-MRA didn't (40.6 ± 13.7 vs. 39.3 ± 13.6%, p = 0.18).Conclusions: PETRA-MRA is accurate and reproducible for quantifying MCA stenosis both pre- and post-stenting compared with DSA and performs better than 3D-TOF-MRA.

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Comparison of image quality, diagnostic confidence and interobserver variability in contrast enhanced MR angiography and 2D time of flight angiography in evaluation of carotid stenosis

British Journal of Radiology ◽

10.1259/bjr/72842752 ◽

2006 ◽

Vol 79 (939) ◽

pp. 201-207 ◽

Cited By ~ 17

Author(s):

D Mitra ◽

D Connolly ◽

S Jenkins ◽

P English ◽

D Birchall ◽

...

Keyword(s):

Image Quality ◽

Carotid Stenosis ◽

Mr Angiography ◽

Interobserver Variability ◽

Time Of Flight ◽

Diagnostic Confidence ◽

Contrast Enhanced

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Carotid Artery Stenosis: Comparison of 3D Time-of-Flight MR Angiography and Contrast-Enhanced MR Angiography at 3T

Radiology Research and Practice ◽

10.1155/2014/508715 ◽

2014 ◽

Vol 2014 ◽

pp. 1-5 ◽

Cited By ~ 1

Author(s):

Ivan Platzek ◽

Dominik Sieron ◽

Philipp Wiggermann ◽

Michael Laniado

Keyword(s):

Carotid Artery ◽

Carotid Artery Stenosis ◽

Mr Angiography ◽

Carotid Arteries ◽

Time Of Flight ◽

Internal Carotid Artery Stenosis ◽

Artery Stenosis ◽

Wilcoxon Test ◽

Tof Mra ◽

Contrast Enhanced

Purpose. The aim of this study was to assess the correlation of 3D time-of-flight MR angiography (TOF MRA) and contrast-enhanced MR angiography (CEMRA) for carotid artery stenosis evaluation at 3T.Material and Methods. Twenty-three patients (5 f, 18 m; mean age 61 y, age range 45–78 y) with internal carotid artery stenosis detected with ultrasonography were examined on a 3.0T MR system. The MR examination included both 3D TOF MRA and CEMRA of the carotid arteries. MR images were evaluated independently by two board-certified radiologists. Stenosis evaluation was based on a five-point scale. Stenosis grades determined by TOF and CEMRA were compared using Spearman’s rank correlation coefficient and the Wilcoxon test. Cohen’s Kappa was used to evaluate interrater reliability.Results. CEMRA detected stenosis in 24 (52%) of 46 carotids evaluated, while TOF detected stenosis in 27 (59%) of 46 carotids. TOF MRA yielded significantly higher results for stenosis grade in comparison to CEMRA (P=0.014). Interrater agreement was very good for both TOF MRA (κ=0.93) and CEMRA (κ=0.93).Conclusion. At 3T, 3D TOF MRA should not be used as replacement for contrast-enhanced MRA of the carotid arteries, as it results in significantly higher stenosis grades.

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