Connecting the DOTs: a novel imaging sign on flat-panel detector CT indicating distal vessel occlusions after thrombectomy

Adnan Mujanovic; Daniel Windecker; Bettina L Serrallach; Christoph C Kurmann; William Almiri; Thomas R Meinel; David J Seiffge; Eike I Piechowiak; Tomas Dobrocky; Jan Gralla; Urs Fischer; Franziska Dorn; René Chapot; Sara Pilgram-Pastor; Johannes Kaesmacher

doi:10.1136/jnis-2023-021218

Connecting the DOTs: a novel imaging sign on flat-panel detector CT indicating distal vessel occlusions after thrombectomy

J Neurointerv Surg. 2024 Jan 19:jnis-2023-021218. doi: 10.1136/jnis-2023-021218. Online ahead of print.

Authors

Adnan Mujanovic^#^{1

2}, Daniel Windecker^#¹, Bettina L Serrallach¹, Christoph C Kurmann^{1

2

3}, William Almiri¹, Thomas R Meinel⁴, David J Seiffge⁴, Eike I Piechowiak¹, Tomas Dobrocky¹, Jan Gralla¹, Urs Fischer^{4

5}, Franziska Dorn⁶, René Chapot⁷, Sara Pilgram-Pastor^#¹, Johannes Kaesmacher^#⁸

Affiliations

¹ Department of Diagnostic and Interventional Neuroradiology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.
² Graduate School of Health Sciences, University of Bern, Bern, Switzerland.
³ Department of Diagnostic, Interventional and Pediatric Radiology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.
⁴ Department of Neurology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland.
⁵ Department of Neruology, University Hospital Basel, Basel, Switzerland.
⁶ Department of Neuroradiology, University Hospital Bonn, Bonn, Germany.
⁷ Department of Neuroradiology and Endovascular Therapy, Alfried Krupp Hospital, Essen, Germany.
⁸ Department of Diagnostic and Interventional Neuroradiology, Inselspital University Hospital Bern, University of Bern, Bern, Switzerland johannes.kaesmacher@insel.ch.

^# Contributed equally.

PMID: 38253377
DOI: 10.1136/jnis-2023-021218

Abstract

Background: Immediate non-contrast post-interventional flat-panel detector CT (FPDCT) has been suggested as an imaging tool to assess complications after endovascular therapy (EVT). We systematically investigated a new imaging finding of focal hyperdensities correlating with remaining distal vessel occlusion after EVT.

Methods: A single-center retrospective analysis was conducted for all acute ischemic stroke patients admitted between July 2020 and December 2022 who underwent EVT and immediate post-interventional FPDCT. A blinded core lab performed reperfusion grading on post-interventional digital subtraction angiography (DSA) images and evaluated focal hyperdensities on FPDCT (here called the distal occlusion tracker (DOT) sign). DOT sign was defined as a tubular or punctiform, vessel confined, hyperdense signal within the initial occlusion target territory. We assessed sensitivity and specificity of the DOT sign when compared with DSA findings.

Results: The median age of the cohort (n=215) was 74 years (IQR 63-82) and 58.6% were male. The DOT sign was positive in half of the cohort (51%, 110/215). The DOT sign had high specificity (85%, 95% CI 72% to 93%), but only moderate sensitivity (63%, 95% CI 55% to 70%) for detection of residual vessel occlusions. In comparison to the core lab, operators overestimated complete reperfusion in a quarter of the entire cohort (25%, 53/215). In more than half of these cases (53%, 28/53) there was a positive DOT sign, which could have mitigated this overestimation.

Conclusion: The DOT sign appears to be a frequent finding on immediate post-interventional FPDCT. It correlates strongly with incomplete reperfusion and indicates residual distal vessel occlusions. In the future, it may be used to complement grading of reperfusion success and may help mitigating overestimation of reperfusion in the acute setting.

Keywords: CT; CT Angiography; Intervention; Stroke.