Delayed Contrast-Enhanced MR Angiography for the Assessment of Internal Carotid Bulb Patency in the Context of Acute Ischemic Stroke: An Accuracy, Interrater, and Intrarater Agreement Study
Résumé
ACKGROUND AND PURPOSE: CTA has shown limited accuracy and reliability in distinguishing tandem occlusions and pseudoocclusions on initial acute stroke imaging. The utility of early and delayed contrast-enhanced MRA in this setting is unknown. We
aimed to assess the accuracy and reliability of early and delayed contrast-enhanced MRA for carotid bulb patency in patients with
acute ischemic stroke.
MATERIALS AND METHODS: We retrospectively reviewed patients who had ICA occlusion and underwent thrombectomy with preprocedural early and delayed contrast-enhanced MRA in a single comprehensive stroke center. During 2 sessions, 10 raters independently assessed 32 cases with early contrast-enhanced MRA (with an additional delayed contrast-enhanced MRA sequence
during the second reading session). Their judgments were compared with DSA as a reference standard. Accuracy and interrater
agreement were measured. Five raters undertook a third reading session to assess intrarater agreement.
RESULTS: Accuracy for the assessment of carotid bulb patency with early contrast-enhanced MRA was limited (69%; 95% CI, 59%–79%),
with moderate interrater agreement (k ¼ 0.42; 95% CI, 0.27–0.55). The second reading with an additional delayed contrast-enhanced
MRA sequence improved both accuracy (82%; 95% CI, 73%–91%; P , .001) (raters corrected 43%–77% of incorrect diagnoses with early
contrast-enhanced MRA alone; mean ¼ 59%) and interrater agreement (k ¼ 0.56; 95% CI, 0.41–0.73; P ¼ .07). Intrarater agreement was
almost perfect, substantial, and moderate for 3, 1, and 1 raters.
CONCLUSIONS: Early contrast-enhanced MRA has limited accuracy and repeatability for the evaluation of carotid bulb patency in
acute ischemic stroke. The additional delayed contrast-enhanced MRA sequence may improve accuracy and reliability.
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