Brain death is a difficult diagnosis to make, relying primarily on clinical examination. Ancillary tests are used when confounders exist. Nuclear medicine perfusion test (NMPT) is currently the preferred test for confirming brain death. Computed tomographic angiography (CTA) may be an alternative test to confirm brain death. It is readily available 24 hours a day at most level I trauma centers and is easy to perform.
Patients with a clinical examination consistent with brain death were selected from the intensive care unit at a 550-bed teaching hospital. The patients underwent NMPT followed immediately by CTA. Both studies were read by radiologists blinded to the results of the alternative study. Absence of brain perfusion confirmed brain death. Multiple independent variables were collected on each patient including demographics, core body temperature, apnea challenge, mechanism of injury, timelines, renal function pre- and posttesting, organ donation, and time to procurement.
There were 25 patients enrolled in the study with multiple injury patterns. No false negative exams were identified on CTA when compared with NMPT. Three patients without flow on NMPT showed minimal flow on CTA. Each of these had open skull defects. Sensitivity of CTA was 0.86 and specificity was 1. There was no induced morbidity with regards to renal failure and organ donation.
CTA is a quick and efficient test for brain death confirmation. CTA demonstrated no false negative studies. The resolution of CTA seems to have an increased sensitivity for cerebral blood flow. Further studies with larger sample sizes need to be performed.