Usefulness of Silent MR Angiography for Intracranial Aneurysms Treated with a Flow-Diverter Device

Oishi, Hidenori; Fujii, Takashi; Suzuki, Maiko; Takano, Nao; Teranishi, Kohsuke; Yatomi, Kenji; Kitamura, Takayuki; Yamamoto, Munetaka; Aoki, Shigeki; Arai, Hajime

doi:10.3174/ajnr.a6047

Cited by 44 publications

(54 citation statements)

References 31 publications

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“…To rate the flow signal in both zTE-and TOF-MRA images, additional DSA imaging was also available and used as a reference. A separate 4-point scale, reported previously (15,27) for similar analysis, was applied also for data analysis. It is defined as: 4= excellent quality, equal to DSA images; 3= good quality, with minimal blurring or artifacts; 2= poor quality, with structures slightly visible and significant blurring; and 1= not visible.…”

Section: Imaging Assessmentmentioning

confidence: 99%

The feasibility of non-contrast-enhanced zero echo time magnetic resonance angiography for characterization of intracranial atherosclerotic disease

Zhang¹,

Dou²,

Yu³

et al. 2021

Quant Imaging Med Surg

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Background: Accurate and non-invasive assessment of intracranial atherosclerotic disease (ICAD) is important because of its effect on treatment planning. The aim of this study is to investigate if zero echo time (zTE) magnetic resonance angiography (zTE-MRA) is feasible in the characterization of ICAD.Methods: A total of 175 patients with ICAD were recruited. ZTE-MRA and time-of-flight (TOF)-MRA sequences were conducted for all participants using a 3T clinical MR system. Forty-one patients also underwent digital subtraction angiography (DSA), and were confirmed to have intracranial arterial stenosis (ICAS). Weighted kappa (κ) statistics were used to assess the inter-observer agreement and diagnostic consistency of both zTE-and TOF-MRA, using DSA as a reference. The Wilcoxon signed-rank test was used to evaluate differences in image quality between zTE-and TOF-MRA images. The nonparametric test of multiple paired samples was used to compare the results of vascular stenosis diagnosis between zTE-, TOF-MRA and DSA.Results: Supported by high inter-observer agreement (weighted κ=0.78), zTE-MRA generated significantly higher scores than TOF-MRA for susceptibility artifact signal (mean: 3.03±0.98 vs. 2.72±1.09; P=0.017) and flow signal in parent artery (mean: 3.63±0.49 vs. 3.07±0.82; P<0.001). Additionally, zTE-MRA showed more robust diagnostic performance than TOF-MRA for patients with ICAD and degree of vascular stenosis (P<0.05), and was highly consistent with reference DSA images (weighted κ=0.80).Conclusions: ZTE-MRA has potential for use as a routine clinical method for patients with ICAD.

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Section: Imaging Assessmentmentioning

confidence: 99%

The feasibility of non-contrast-enhanced zero echo time magnetic resonance angiography for characterization of intracranial atherosclerotic disease

Zhang¹,

Dou²,

Yu³

et al. 2021

Quant Imaging Med Surg

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“…Our routine MRA follow-up involves the acquisition of contrast MRA images only when noncontrast MRA results are shown to be or are likely to be equivocal. One potential solution for this may be the use of newer techniques that were not available to us, such as “silent MRA”, which allows better assessment of the stent lumen [ 22 ]. Finally, notwithstanding the facts that our study: (1) has a fairly large number of flow-diverted aneurysms treated and followed by a single group of operators and (2) is the largest series to date focusing strictly on MRA follow-up of flow diverters, the number of aneurysms treated with the new Evolve device in the artifact measurement cohort was lowered significantly due to the selection criteria for the relevant measurement.…”

Section: Limitationsmentioning

confidence: 99%

The implications of magnetic resonance angiography artifacts caused by different types of intracranial flow diverters

Batur

Sayın

Balcı

et al. 2021

Journal of Cardiovascular Magnetic Resonance

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Background Serial cerebral angiographic imaging is necessary to ensure cerebral aneurysm occlusion after flow diverter placement. Time-of-flight (TOF)-magnetic resonance angiography (MRA) is used for this purpose due to its lack of radiation, contrast media and complications. The comparative diagnostic yield of TOF-MRA for different flow diverters has not been previously analyzed. Purpose To evaluate the diagnostic accuracy of TOF-MRA in cerebral aneurysms treated w divertersith different flow diverters. Materials and Methods Flow-diverted patients whose cerebral follow-up MRA and digital subtraction angiograms (DSA) were obtained within 6 weeks were retrospectively identified. The DSA (as gold standard) and MRA images of these patients were compared by two readers (blinded to both patient data and endovascular procedure data) for residual aneurysms and the status of the parent artery for each type of flow diverter. In a second group of patients, magnetic susceptibility artifacts were manually measured and compared for different FDs. Results Seventy-six patients (85 aneurysms) were included in group one, and 86 patients (95 aneurysms) were included in group 2. TOF-MRA and DSA showed almost perfect agreement for residual aneurysms (κ = 0.88, p < 0.001) (positive predictive value (PPV) = 1.00, specificity = 1.00, negative predictive value (NPV) = 0.89, sensitivity = 0.89). Intermodality agreement (κ = 0.97 vs. κ = 0.74, p < 0.005) and sensitivity (0.97 vs. 0.77, NPV: 0.96 vs. 0.77) were highest with nitinol stents. MRA and DSA showed no agreement for occluded or stenotic parent vessels (κ = 0.13, p = 0.015, specificity = 0.44, NPV = 1.00, sensitivity = 1.00). Specificity was lower in chromium-cobalt based FDs than in nitinol devices (specificity = 0.08 vs. 0.60). Chromium-cobalt stents generated the largest artifacts (p < 0.005). The size of the device-related artifact, in millimeters, increased in respective order, for the Silk, Derivo, Pipeline and Surpass devices. Conclusion Unlike DSA, TOF-MRA is susceptible to dissimilarities between flow diverters. MRA is not well-suited for research studies comparing different flow diverters. Nitinol FDs appear to be advantageous for TOF-MRA follow-up so as not to miss small aneurysm remnants or clinically relevant parent artery stenosis.

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“… 6) Because repeated DSA examinations are invasive for patients, a less invasive imaging modality has been needed. Oishi et al 7) reported the usefulness of silent MRA for intracranial aneurysms treated with the PED. In the present case, the 6-month follow-up silent MRA showed residual blood flow within the aneurysm.…”

Section: Discussionmentioning

confidence: 99%

Defective Endothelialization of Pipeline Embolization Device after Flow Diverter Therapy: An Autopsy Case Report

Oishi

Mishima

Yatomi

et al. 2021

NMC Case Report Journal

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The authors report a rare autopsy case. A 59-year-old woman underwent flow diverter (FD) therapy using a pipeline embolization device (PED) for a large paraclinoid internal carotid artery aneurysm. Follow-up magnetic resonance (MR) examinations were performed 6 months after the treatment. Although the T2-weighted images showed progressive thrombosis of the aneurysm, the silent MR angiography (MRA) clearly showed the residual blood flow within the aneurysm. The patient committed suicide 2 months after the follow-up MR examinations. An autopsy specimen showed a small section of the defective membranes with the PED that matched the entry point of residual blood flow seen clearly in the silent MRA. Macroscopic photograph and hematoxylin and eosin stained sections showed defective endothelialization. In contrast, complete endothelialization was observed in membranes covering the PED. The autopsy findings after FD therapy showed defective endothelialization that perfectly matched and corroborated the silent MRA findings.

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Usefulness of Silent MR Angiography for Intracranial Aneurysms Treated with a Flow-Diverter Device

Cited by 44 publications

References 31 publications

The feasibility of non-contrast-enhanced zero echo time magnetic resonance angiography for characterization of intracranial atherosclerotic disease

The feasibility of non-contrast-enhanced zero echo time magnetic resonance angiography for characterization of intracranial atherosclerotic disease

The implications of magnetic resonance angiography artifacts caused by different types of intracranial flow diverters

Defective Endothelialization of Pipeline Embolization Device after Flow Diverter Therapy: An Autopsy Case Report

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