Accuracy Confirmation of the Compress-Sensing Technique in the TOF MRA Test using Flow Phantom

2019 ◽  
Vol 24 (4) ◽  
pp. 719-724
Author(s):  
Seongho Kim ◽  
Sejong Yoo ◽  
Mincheol Jeon ◽  
Jinseo Park ◽  
Soonyong Kwon ◽  
...  
Keyword(s):  
Compress Sensing ◽  
Tof Mra ◽  
Flow Phantom

Evaluation of Time-of-Flight and Phase-Contrast MRA Sequences at 1.0 T for Diagnosis of Carotid Artery Disease

1996 ◽  
Vol 37 (1P1) ◽  
pp. 267-277 ◽  
Author(s):  
M. Cronqvist ◽  
F. Ståhlberg ◽  
E.-M. Larsson ◽  
M. Lönntoft ◽  
S. Holtås
Keyword(s):  
Phase Contrast ◽  
Visual Inspection ◽  
Carotid Artery Disease ◽  
Acquisition Time ◽  
Tof Mra ◽  
Flow Phantom ◽  
Signal Evaluation ◽  
Artery Disease ◽  
Phantom Studies

Purpose and Material: The aim of this work was, firstly, to compare different manufacturer-provided MRA sequences in a 1.0 T MR unit, with respect to the visibility of an artificial stenosis in a flow phantom and, secondly, to evaluate the same sequences in healthy volunteers with respect to S/N ratio levels and practical in vivo implementation routines. Methods: The studied sequences were 2D and 3D TOF and sequences with an acquisition time of approximately 10 min. Quantitative signal evaluation was made using single transverse partitions in all phantom experiments. MIP angiograms and MPR reconstructions were made for visual inspection of image quality. In vivo, the images were individually evaluated by visual inspection by experienced neuroradiologists. Results: In the evaluation of the grade and length of a stenosis, a combination of MIP and MPR was seen to be the optimal and necessary procedure. A shortening of TE played an important and significant role in the visualization of the poststenotic flow in the phantom using TOF MRA. However, the shortest TE values gave poor S/N ratio in vivo. The good results achieved in the phantom studies for 3D phase-contrast were somewhat reversed in the volunteer studies, whereas 3D TOF sequences showed good results in both the phantom and the volunteer studies.

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

VASA ◽  
2014 ◽  
Vol 43 (4) ◽  
pp. 278-283 ◽  
Author(s):  
Qian Chen ◽  
Rongfeng Qi ◽  
Xiaoqing Cheng ◽  
Changsheng Zhou ◽  
Song Luo ◽  
...  
Keyword(s):  
Image Quality ◽  
Moyamoya Disease ◽  
Mr Angiography ◽  
Time Of Flight ◽  
Consecutive Series ◽  
Tof Mra ◽  
Bypass Patency ◽  
Significant Difference ◽  
Contrast Technique ◽  
Vessel Integrity

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.

scholarly journals Non-Pathological Opacification of the Cavernous Sinus on Brain CT Angiography: Comparison with Flow-Related Signal Intensity on Time-of-Flight MR Angiography

Healthcare ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 94
Author(s):  
Sun Ah Heo ◽  
Eun Soo Kim ◽  
Yul Lee ◽  
Sang Min Lee ◽  
Kwanseop Lee ◽  
...  
Keyword(s):  
Cavernous Sinus ◽  
Signal Intensity ◽  
Time Of Flight ◽  
Weighted Kappa ◽  
Wilcoxon Test ◽  
Tof Mra ◽  
Superior Petrosal Sinus ◽  
Grade Difference ◽  
Diagnostic Modalities ◽  
The Right

Purpose: To investigate the non-pathological opacification of the cavernous sinus (CS) on brain computed tomography angiography (CTA) and compare it with flow-related signal intensity (FRSI) on time-of-flight magnetic resonance angiography (TOF-MRA). Methods: Opacification of the CS was observed in 355 participants who underwent CTA and an additional 77 participants who underwent examination with three diagnostic modalities: CTA, TOF-MRA, and digital subtraction angiography (DSA). Opacification of the CS, superior petrosal sinus (SPS), inferior petrosal sinus (IPS), and pterygoid plexus (PP) were also analyzed using a five-point scale. The Wilcoxon test was used to determine the frequencies of the findings on each side. Additionally, the findings on CTA images were compared with those on TOF-MRA images in an additional 77 participants without dural arteriovenous fistula (DAVF) using weighted kappa (κ) statistics. Results: Neuroradiologists identified non-pathological opacification of the CS (n = 100, 28.2%) on brain CTA in 355 participants. Asymmetry of opacification in the CS was significantly correlated with the grade difference between the right and left CS, SPS, IPS, and PP (p < 0.0001 for CS, p < 0.0001 for SPS, p < 0.0001 for IPS, and p < 0.05 for PP). Asymmetry of the opacification and FRSI in the CS was observed in 77 participants (CTA: n = 21, 27.3%; TOF-MRA: n = 22, 28.6%). However, there was almost no agreement between CTA and TOF-MRA (κ = 0.10, 95% confidence interval: −0.12–0.32). Conclusion: Asymmetry of non-pathological opacification and FRSI in the CS may be seen to some extent on CTA and TOF-MRA due to anatomical variance. However, it shows minimal reliable association with the FRSI on TOF-MRA.

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

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

<b><i>Background:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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). <b><i>Conclusion:</i></b> The intralateral and perilateral ventricular arteries on the original axial TOF-MRA images might suggest the hemorrhagic type of moyamoya disease prior to onset.

Influence of Gain Adjustment on 3-Dimensional Power Doppler Indices and on Spatiotemporal Image Correlation Volumetric Pulsatility Indices Using a Flow Phantom

2013 ◽  
Vol 32 (10) ◽  
pp. 1831-1836 ◽  
Author(s):  
Andre H. Miyague ◽  
Nicholas J. Raine-Fenning ◽  
Theo Z. Pavan ◽  
Lukasz T. Polanski ◽  
Miriam N. Baumgarten ◽  
...  
Keyword(s):  
Power Doppler ◽  
Image Correlation ◽  
3 Dimensional ◽  
Flow Phantom ◽  
Doppler Indices ◽  
Gain Adjustment ◽  
Spatiotemporal Image Correlation

Prototype of MRI Flow Phantom for Dynamic Imaging of Cerebrospinal Fluid Flow

2021 ◽  
Vol 2021 (0) ◽  
pp. 1P2-C07
Author(s):  
Kazunori HOSOTANI ◽  
Keitaro TAKAKI ◽  
Yuka MARUO ◽  
Kazuhiro TAKEUCHI ◽  
Atsushi ONO ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Fluid Flow ◽  
Dynamic Imaging ◽  
Cerebrospinal Fluid Flow ◽  
Flow Phantom

Abstract 249: Stationary Signal and Flow Velocity Assessment by MRI of a New Nitinol Nanocomposite Polymer Stent-Graft

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Mital Desai ◽  
Rachel E Clough ◽  
Nicholas R Gaddum ◽  
Kawal Rhode ◽  
Xiang Zhou ◽  
...  
Keyword(s):  
Steady Flow ◽  
Stent Graft ◽  
Signal Attenuation ◽  
Stent Grafts ◽  
Mean Velocity ◽  
Nanocomposite Polymer ◽  
Significant Difference ◽  
Flow Phantom ◽  
Flow Flux ◽  
Commercial Device

Objective: To assess MRI compatibility and suitability of a new sutureless stent-graft made from Nitinol bonded to nanocomposite polymer (NP). Methods: 1. Using MRI and Magnevist contrast, isotropic 3D T1-weighted FFE images of NP stent-graft were acquired to observe artefacts and stationary signal attenuation. Average signal magnitude was calculated. Medtronic ValiantTM was used as control. 2. In second stage, steady flow phantom was setup for flow-encoded MRI signal assessment of both stent-grafts. Baseline values were obtained by velocity measurements without stent-graft using identical settings. 2D through-plane phase contrast images were acquired and average velocity and amount of flow (flux) were calculated. Results: On static assessment of NP and ValiantTM stent-grafts no significant image artefacts were seen. The signal inside and outside the ValiantTM stent-graft was 644.2(SD 36.2) and 659.6(SD 85.8) respectively. The signal attenuation for this device was 2.39%. The signal inside and outside the NP stent graft was 1561.7(SD 31.2) and 1595.5(SD 40.8) respectively with comparable signal attenuation of 2.16%. In MRI velocity attenuation study, steady flow phantom was set at mean volume of 105.3 ml and mean velocity of 79.5 cm/sec. Flux measured in ValiantTM stent-graft was 102±2.27 ml/sec with no significant difference to baseline (104±1.98 ml/sec; P=0.892). Similarly flux for NP stent-graft at mean stroke volume 104.4 ml and mean velocity of 92.3 cm/sec showed no difference to baseline (99.8±2.4 vs. 104±0.96 ml/sec; P=0.176). There was no significant difference in flux between Medtronic and NP stent-grafts (102±2.27 vs. 99.8±2.4 ml/sec; P=0.328). Conclusion: NP stent-graft does not display any material-induced artefacts on MRI. On flow assessment, signal attenuation is comparable with the commercial device. These properties are important in developing this stent-graft, compliant, durable, visco-elastic, biocompatible and anti-thrombogenic, for future clinical use.

Abstract 1122‐000172: High Resolution Vessel Wall Imaging and Cerebrovascular Plaques: Comparison with DSA, MRA, and CTA

2021 ◽  
Vol 1 (S1) ◽  
Author(s):  
Rami Fakih ◽  
Alberto Miller ◽  
Ashrita Raghuram ◽  
Sebastian Herrera ◽  
Sedat Kandemirli ◽  
...  
Keyword(s):  
Vessel Wall ◽  
The Other ◽  
Imaging Modalities ◽  
Plaque Burden ◽  
Rater Agreement ◽  
Cross Sectional ◽  
Tof Mra ◽  
Plaque Detection ◽  
Wall Imaging

Introduction : Current imaging modalities might underestimate the presence and severity of intracranial atherosclerosis (ICAD). High resolution vessel wall imaging (HR‐VWI) MRI emerged as a powerful tool to diagnose plaques not detected on routine imaging. We aim to compare different imaging modalities (HR‐VWI MRI; digital subtraction angiogram (DSA); Time‐of‐flight (TOF) MRA; and CTA) in the identification and characterization of intracranial atherosclerotic culprit plaques. Methods : Patients diagnosed with ICAD were prospectively imaged with HR‐VWI MRI. Culprit plaques were identified based on the likelihood of causing the stroke. Using cross‐sectional images of intracranial vessels, regions of interest (ROI) were delineated. Then, diameters and ROI areas were measured for the purpose of calculating the following variables: degree of stenosis (DS) at the plaque level, plaque burden (PB), and remodeling index (RI). Additional imaging modalities (DSA, TOF MRA, and CTA) were identified retrospectively for each patient. The sensitivity of detecting a culprit plaque as well as the correlations between the different variables were analyzed for each modality. Linear regression analysis was used to determine the association of DS with PB and RI. Interobserver agreement on the determination of a culprit plaque on every imaging modality was evaluated. Results : A total of 44 patients who underwent HR‐VWI had ICAD and were included in the final analysis. Of those, 34 had CTA, 18 had TOF‐MRA, and 18 had DSA. Using HR‐VWI as gold standard, the sensitivity for culprit plaque detection was 88% for DSA, 78% for TOF MRA, and 76% for CTA. We found no difference between the DS in all four modalities using measured cross‐sectional diameters, but difference was found when measuring ROI areas to calculate DS. There was a significant positive correlation between PB and DS on HR‐VWI MRI (p<0.001), but not on the DSA (p = 0.168), MRA (p = 0.144), or CTA (p = 0.253), and a significant negative correlation between RI and DS on HR‐VWI MRI (p = 0.003), but not on DSA (p = 0.783), MRA (p = 0.405), or CTA (p = 0.751). PB and RI predicted the degrees of stenosis on HR‐VWI, but not on the other modalities. There was good inter‐rater agreement for culprit plaque detection on HR‐VWI (k = 0.48, p = 0.001), but no agreement was found on the other modalities. Conclusions : HR‐VWI MRI can locate otherwise undetectable plaques on conventional imaging through the ability to measure plaque burden, an essential component for characterization of plaques severity and a strong predictor of stenosis. HR‐VWI also showed more accurate measurements of degree of stenosis through measurement of ROI areas, and had good inter‐rater agreement for accurate plaque detection, compared to DSA, MRA, and CTA.

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