Assessment of Vessel Density on Non-Contrast Computed Tomography to Detect Basilar Artery Occlusion

Abstract

Introduction: Basilar artery occlusion (BAO) may be clinically occult due to variable and non-specific symptomatology. We evaluated the qualitative and quantitative determination of a hyperdense basilar artery (HDBA) on non-contrast computed tomography (NCCT) brain for the diagnosis of BAO. Methods:We conducted a case control study of patients with confirmed acute BAO vs a control group of suspected acute stroke patients without BAO. Two EM attending physicians, one third-year EM resident, and one medical student performed qualitative and quantitative assessments for the presence of a HDBA on axial NCCT images. Our primary outcome measures were sensitivity and specificity for BAO. Our secondary outcomes were inter-rater and intra-rater reliability of the qualitative and quantitative assessments. Results:We included 60 BAO and 65 control patients in our analysis. Qualitative assessment of the hyperdense basilar artery sign was poorly sensitive (54%-72%) and specific (55%-89%). Quantitative measurement improved the specificity of hyperdense basilar artery assessment for diagnosing BAO, with a threshold of 61.0-63.8 Hounsfield units demonstrating relatively high specificity of 85%-94%. There was moderate inter-rater agreement for the qualitative assessment of HDBA (Fleiss' kappa statistic 0.508, 95% confidence interval: 0.435-0.581). Agreement improved for quantitative assessments, but still fell in the moderate range (Shrout-Fleiss intraclass correlation coefficient: 0.635). Intra-rater reliability for the quantitative assessments of the two attending physician reviewers demonstrated substantial consistency. Conclusion:Our results highlight the importance of carefully examining basilar artery density when interpreting the NCCT of patients with altered consciousness or other signs and symptoms concerning for an acute basilar artery occlusion. If the Hounsfield unit density of the basilar artery exceeds 61 Hounsfield units, BAO should be highly suspected. [

Age and discharge modified Rankin score are associated with 90-Day functional outcome after basilar artery occlusion treated with endovascular therapy

“…While PC-ASPECTS on DWI MRI 15,37 and CTA-SI 24,38 has been shown to predict outcome in BAO patients, we chose to investigate PC-ASPECTS applied to the noncontrast head CT to determine its prognostic significance on a more readily available imaging study. No significant association with outcome was discovered when PC-ASPECTS was treated as a continuous or binary variable.…”

“…BAO site was characterized as proximal (origin of basilar artery to origin of anterior inferior cerebellar arteries [AICAs]), middle (origin of AICAs to origin of superior cerebellar arteries [SCAs]), and distal (origin of SCAs to basilar tip), as previously described. 23 Additional imaging characteristics included the presence of hyperdense basilar on CT (defined as 61 Hounsfield Units or above 24 ); posterior circulation Acute Stroke Prognosis Early Computed Tomography Score (pc-ASPECTS), 25 with favorable score defined as !7; and posterior circulation collateral score (PC-CS) (poor 0-3; intermediate 4-5; good 6-10). 26,27 All imaging characteristics were determined by imaging review and agreement between a board-certified neuroradiologist and board-certified vascular neurologist.…”

Cerebral blood volume index as a predictor of functional independence after basilar artery thrombectomy

“…BAO site was categorized as proximal (origin of basilar artery to origin of anterior inferior cerebellar arteries [AICAs]), middle (origin of AICAs to origin of superior cerebellar arteries [SCAs]), and distal (origin of SCAs to basilar tip), as previously described 31 . Hyperdense basilar artery on CT (defined as ≥ 61 Hounsfield units) was determined by measuring Hounsfield units on the axial CT slice deemed to have the densest section of basilar artery and zooming in to 400% with a circular region of interest, as previously described 32 . BAO site, the presence of hyperdense basilar artery, pc‐ASPECTS on CT and CTA‐SI, 18 PC‐CS, 19 and the BATMAN score were determined by imaging review and agreement between a board‐certified neuroradiologist and board‐certified vascular neurologist.…”

“…31 Hyperdense basilar artery on CT (defined as ≥ 61 Hounsfield units) was determined by measuring Hounsfield units on the axial CT slice deemed to have the densest section of basilar artery and zooming in to 400% with a circular region of interest, as previously described. 32 BAO site, the presence of hyperdense basilar artery, pc-ASPECTS on CT and CTA-SI, 18 PC-CS, 19 and the BATMAN score were determined by imaging review and agreement between a board-certified neuroradiologist and board-certified vascular neurologist. Post-thrombectomy reperfusion was determined postprocedure by neuro-interventionalist calculated modified Thrombolysis in Cerebral Infarction (TICI) score.…”