Non-enhanced CT Maximum Intensity Projections for the Detection of Large Vessel Occlusions

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Large vessel occlusions (LVO) require timely identification for effective endovascular therapy in acute ischemic stroke.
• CT angiography (CTA) is standard for LVO detection but adds time and contrast, potentially delaying treatment.
• Non-enhanced CT maximum intensity projections (NECT-MIPs) present a potential faster alternative for LVO identification.

Purpose of the Study:

• To evaluate the diagnostic performance of NECT-MIPs for detecting LVO in acute stroke patients.
• To compare the accuracy of NECT-MIPs against the gold standard CTA.
• To assess inter-rater agreement among different levels of medical expertise (Faculty, Fellows, ACPs).

Main Methods:

• Retrospective review of acute stroke patients with LVO from the UCSD Stroke Registry (6/2014-7/2016).
• Evaluation of NECT-MIPs for LVO detection, with CTA as the reference standard.
• Stratification of results by reviewer experience and assessment of inter-rater agreement using Fleiss' Kappa Coefficient.

Main Results:

• NECT-MIPs demonstrated high sensitivity and specificity for detecting LVO, particularly for internal carotid artery/M1 segment occlusions (Faculty: 95%/92%).
• Performance varied for M2 and basilar occlusions, with lower sensitivity reported for M2 segments (Faculty: 42%).
• Inter-rater agreement was fair to good among Faculty (Kappa: 0.75 for ICA/M1) but lower among Fellows and ACPs (Kappa: 0.57 for ICA/M1).

Conclusions:

• NECT-MIPs show high accuracy for LVO detection compared to CTA.
• Inter-rater agreement is acceptable and higher with increased reviewer experience.
• NECT-MIPs may streamline LVO identification, potentially reducing door-to-needle and door-to-intervention times.