CT after interhospital transfer in acute ischemic stroke: Imaging findings and impact of prior intravenous contrast administration

Franziska Mueller; Matthias P Fabritius; Lena Stueckelschweiger; Sophia Kiesl; Sebastian Moench; Steffen Tiedt; Jan Rémi; Lars Kellert; Moriz Herzberg; Clemens Küpper; Konstantinos Dimitriadis; Jens Ricke; Daniel Puhr-Westerheide; Thomas Liebig; Wolfgang G Kunz; Paul Reidler

doi:10.3389/fneur.2022.1023147

CT after interhospital transfer in acute ischemic stroke: Imaging findings and impact of prior intravenous contrast administration

Front Neurol. 2022 Dec 7:13:1023147. doi: 10.3389/fneur.2022.1023147. eCollection 2022.

Authors

Franziska Mueller¹, Matthias P Fabritius¹, Lena Stueckelschweiger¹, Sophia Kiesl¹, Sebastian Moench¹, Steffen Tiedt², Jan Rémi³, Lars Kellert³, Moriz Herzberg⁴, Clemens Küpper³, Konstantinos Dimitriadis^{2

3}, Jens Ricke¹, Daniel Puhr-Westerheide¹, Thomas Liebig⁵, Wolfgang G Kunz¹, Paul Reidler¹

Affiliations

¹ Department of Radiology, University Hospital, LMU Munich, Munich, Germany.
² Institute for Stroke and Dementia Research, LMU Munich, Munich, Germany.
³ Department of Neurology, University Hospital, LMU Munich, Munich, Germany.
⁴ Department of Diagnostic and Interventional Radiology, University Hospital Wuerzburg, Wuerzburg, Germany.
⁵ Department of Neuroradiology, University Hospital, LMU Munich, Munich, Germany.

Abstract

Objectives: Large vessel occlusion (LVO) stroke patients routinely undergo interhospital transfer to endovascular thrombectomy capable centers. Imaging is often repeated with residual intravenous (IV) iodine contrast at post-transfer assessment. We determined imaging findings and the impact of residual contrast on secondary imaging. Anterior circulation LVO stroke patients were selected out of a consecutive cohort. Directly admitted patients were contrast naïve, and transferred patients had previously received IV iodine contrast for stroke assessment at the referring hospital. Two independent readers rated the visibility of residual contrast on non-contrast computed tomography (CT) after transfer and assessed the hyperdense vessel sign. Multivariate linear regression analysis was used to investigate the association of the Alberta Stroke Program Early CT score (ASPECTS) with prior contrast administration, time from symptom onset (TFSO), and CTP ischemic core volume in both directly admitted and transferred patients.

Results: We included 161 patients, with 62 (39%) transferred and 99 (62%) directly admitted patients. Compared between these groups, transferred patients had a longer TFSO-to-imaging at our institution (median: 212 vs. 75 min, p < 0.001) and lower ASPECTS (median: 8 vs. 9, p < 0.001). Regression analysis presented an independent association of ASPECTS with prior contrast administration (β = -0.25, p = 0.004) but not with TFSO (β = -0.03, p = 0.65). Intergroup comparison between transferred and directly admitted patients pointed toward a stronger association between ASPECTS and CTP ischemic core volume in transferred patients (β = -0.39 vs. β = -0.58, p = 0.06). Detectability of the hyperdense vessel sign was substantially lower after transfer (66 vs. 10%, p < 0.001).

Conclusion: Imaging alterations due to residual IV contrast are frequent in clinical practice and render the hyperdense vessel sign largely indetectable. Larger studies are needed to clarify the influence on the association between ASPECTS and ischemic core.

Keywords: CT; IV contrast; interhospital transfer; perfusion; stroke.