Diagnosing Early Ischemic Changes with the Latest-Generation Flat Detector CT: A Comparative Study with Multidetector CT

Abstract

Background and purpose: One-stop management of mechanical thrombectomy-eligible patients with large-vessel occlusion represents an innovative approach in acute stroke treatment. This approach reduces door-to-reperfusion times by omitting multidetector CT, using flat detector CT as pre-mechanical thrombectomy imaging. The purpose of this study was to compare the diagnostic performance of the latest-generation flat detector CT with multidetector CT.

Materials and methods: Prospectively derived data from patients with ischemic stroke with large-vessel occlusion and mechanical thrombectomy were analyzed in this monocentric study. All included patients underwent multidetector CT before referral to our comprehensive stroke center and flat detector CT in the angiography suite before mechanical thrombectomy. Diagnosis of early ischemic signs, quantified by the ASPECTS, was compared between modalities using cross tables, the Pearson correlation, and Bland-Altman plots. The predictive value of multidetector CT- and flat detector CT-derived ASPECTS for functional outcome was investigated using area under the receiver operating characteristic curve analysis.

Results: Of 25 patients, 24 (96%) had flat detector CT with sufficient diagnostic quality. Median multidetector CT and flat detector CT ASPECTSs were 7 (interquartile range, 5.5-9 and 4.25-8, respectively) with a mean period of 143.6 ± 49.5 minutes between both modalities. The overall sensitivity was 85.1% and specificity was 83.1% for flat detector CT ASPECTS compared with multidetector CT ASPECTS as the reference technique. Multidetector CT and flat detector CT ASPECTS were strongly correlated (r = 0.849, P < .001) and moderately predicted functional outcome (area under the receiver operating characteristic curve, 0.738; P = .007 and .715; P = .069, respectively).

Conclusions: Determination of ASPECTS on flat detector CT is feasible, showing no significant difference compared with multidetector CT ASPECTS and a similar predictive value for functional outcome. Our findings support the use of flat detector CT for emergency stroke imaging before mechanical thrombectomy to reduce door-to-groin time.

Fig 1.

Initial MDCT in the peripheral stroke center shows hypodensity of the right lentiform nucleus (white arrow) and no other early ischemic signs on the ganglionic (A) or supraganglionic (B) level. An ASPECTS of 9 was rated on MDCT images. C, FDCT acquired in our comprehensive stroke center 172 minutes after the initial CT shows hypodensities of the right lentiform nucleus (black arrow) and insula. No early ischemic signs were detected on the supraganglionic level, resulting in an ASPECTS of 8.

Fig 2.

A, Initial MDCT in the peripheral stroke center shows hypodensities of the left striatum, insula, internal capsule, M1, M2, and M3 segments. B, In the supraganglionic levels, we observe early signs in the M4, M5, and M6 segments, resulting in an ASPECTS of 0. C and D, FDCT acquired in our comprehensive stroke center 94 minutes after the initial CT shows early ischemic signs in the left anterior cerebral artery and MCA territories, resulting in an ASPECTS of 2. The M3 and M6 segments are not classified as ischemic on FDCT images.

Fig 3.

Pearson correlation between MDCT and FDCT ASPECTS.

Fig 4.

Bland-Altman plot of MDCT and FDCT ASPECTS.

Fig 5.

Area under the receiver operating curve analysis for the predictive value of MDCT and FDCT ASPECTS for favorable functional outcome (mRS ≤ 2).