Dead or alive? New confirmatory test using quantitative analysis of computed tomographic angiography

Area of Science:

• Neurology
• Radiology
• Medical Diagnostics

Background:

• Clinical examination can be unreliable for diagnosing brain death (BD).
• Nuclear medicine perfusion test (NMPT) is the preferred confirmatory test for BD at our institution.
• Computed tomographic angiography (CTA) has emerged as a potential alternative for BD confirmation.

Purpose of the Study:

• To quantitatively analyze CTA for BD diagnosis.
• To assess the accuracy of CTA compared to NMPT.
• To define specific parameters for BD confirmation using CTA.

Main Methods:

• Prospective clinical study (2007-2014) of 60 clinically brain dead patients and 20 controls.
• NMPT performed as the reference standard, immediately followed by CTA.
• Quantitative assessment of CTA Hounsfield units in the middle cerebral artery (M1), anterior cerebral artery (A1), and basilar artery (BA).

Main Results:

• 88% of patients showed absent cerebral blood flow (CBF) on NMPT.
• Only 50% showed absent CBF on CTA.
• Established criteria using CTA Hounsfield units to differentiate preserved perfusion from stasis filling, with significant variations across all measured arteries (p < 0.001).

Conclusions:

• A CTA Hounsfield unit value less than 80 in M1, A1, and BA correlates with absent CBF on NMPT.
• This threshold indicates a lack of physiologic cerebral perfusion, confirming brain death.
• CTA demonstrates high diagnostic accuracy for BD confirmation, with 97% sensitivity and 100% specificity.