Three‐dimensional spin‐echo‐based black‐blood MRA in the detection of vasospasm following subarachnoid hemorrhage

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Abstract
Background: Black‐blood MR angiography (BBMRA), which utilizes a non‐T1 contrast spin‐echo type technique, has been expected to overcome several issues associated with time‐of‐flight (TOF) MRA.Purpose: To investigate the efficacy of BBMRA to detect vasospasms following subarachnoid hemorrhage (SAH).Study Type: Retrospective.Subjects: Seventeen patients with SAH in their early posttreatment period.Field Strength/Sequence: BBMRA, which uses a volumetric isotropic turbo spin‐echo acquisition (VISTA), and TOF‐MRA on 1.5T scanners.Assessment: Visualization of supratentorial arteries and veins in BBMRA was rated on a 4‐point scale by two neuroradiologists. Another neuroradiologist independently assessed TOF‐MRA. The degree of the vasospasm was then evaluated using a 3‐point scale by the same readers. The diagnostic performance of the MRAs was evaluated using computed tomography angiography (CTA) or digital subtraction angiography (DSA) as the standard of reference.Statistical Tests: Wilcoxon signed rank test, McNemar test, and Cohen's kappa coefficient.Results: BBMRA provided superior visualization of the anterior and middle cerebral arteries than TOF‐MRA (P < 0.05). The depiction of the veins was more pronounced on BBMRA (P < 0.01). Of the 166 arterial segments evaluated by CTA or DSA, 23 (13.9%) could not be assessed using TOF‐MRA because of high signal hemorrhage, whereas BBMRA enabled visualization of all the segments. Vasospasm was confirmed in 30 segments by CTA or DSA. The sensitivity, specificity, and positive and negative predictive values were 73, 96, 76, and 95 for TOF‐MRA and 91, 100, 100, and 98 for BBMRA, respectively (P = 0.13 for sensitivity, P = 0.06 for specificity). The agreement of the degree of vasospasm between MRA and the standard of reference, as indicated by kappa value, was 0.71 (95% confidence interval [CI], 0.55–0.87) for TOF‐MRA and 0.91 (95% CI, 0.82–0.99) for BBMRA.Data Conclusion: BBMRA, owing to its contrast properties, may be superior to TOF‐MRA for the evaluation of intracranial arteries after SAH.Level of Evidence: 3Technical Efficacy: Stage 2J. Magn. Reson. Imaging 2019;49:800–807.