CT angiography for brain death diagnosis

Abstract

Background and purpose: Lack of cerebral circulation is an important confirmatory test for brain death (BD). Conventional angiography remains the standard imaging method, but CT angiography (CTA) is emerging as an alternative. France accepts BD diagnoses relying on a score based on lack of opacification of 7 intracerebral vessels in CTA images. The purpose of this study was to validate the efficiency of this score and to evaluate the sensitivity of a novel 4-point CTA score in confirming BD.

Materials and methods: A prospective multicentric study was conducted during 12 months with 105 patients referred for CTA to confirm a clinical diagnosis of BD. Clinical data were recorded. CTA images were interpreted first by local radiologists at the referent center, resulting in a 7-point score based on lack of opacification of the pericallosal and cortical segments of the middle cerebral arteries (MCAs), internal cerebral veins (ICVs), and 1 great cerebral vein per patient and, second, by a consensus panel of 3 expert radiologists, blinded to the initial scores, resulting in novel 4-point scores based on the lack of opacification of the cortical segments of the MCAs and ICVs.

Results: Injection of contrast medium did not alter renal function. With the initial 7-point score, sensitivity was 62.8%. With the simplified 4-point score, sensitivity was 85.7% and specificity was 100%. Opacification of ICVs was absent in 98.1% of patients.

Conclusions: Lack of opacification in the cortical segments of the MCAs and internal veins in CTA is efficient and reliable for confirming BD.

Fig 1.

CTA: normal aspect in a healthy adult. A, All intracranial vessels, pericallosal arteries, MCAs, ICVs (arrows), straight sinus, and superior sagittal sinus, are opacified. B, Cortical arteries are opacified (arrows). In both, superficial temporal arteries are visible.

Fig 2.

CTA in BD before and 60 seconds after contrast medium injection. A and B, Unenhanced CT sections. C and D, Corresponding CT sections with identical window settings 60 seconds after contrast medium injection, demonstrating cerebral CT silence: absence of visualization of ICVs and cortical segments of the MCAs. Both superficial temporal arteries are opacified, indicating that contrast medium has been correctly injected (arrows).