Dynamic evaluation of stasis filling phenomenon with computed tomography in diagnosis of brain death

Stasis filling, defined as delayed, weak, and persistent opacification of proximal segments of the cerebral arteries, is frequently found in brain dead patients. This phenomenon causes a major problem in the development of reliable computed tomographic angiography (CTA) protocol in the diagnosis of brain death (BD). The aim of our study was to characterize stasis filling in the diagnosis of BD. To achieve this, we performed a dynamic evaluation of contrast enhancement of the cerebral and extracranial arteries in patients with BD and controls.

Study population included 30 BD patients, who showed stasis filling in computed tomographic perfusion (CTP) series. Thirty patients, after clipping of an intracranial aneurysm, constituted the control group. The study protocol consisted of CTA, CTP, and angiography. Time-density curves (TDCs) of cerebral and extracranial arteries were generated using 40-s series of CTP.

Cerebral TDCs in BD patients represented flat curves in contrast to TDCs in controls, which formed steep and narrow Gaussian curves. We found longer time to peak enhancement in BD patients than in controls (32 vs. 21 s; p < 0.0001). In BD patients, peak enhancement in the cerebral arteries occurred with a median delay of 14.5 s to peak in extracranial arteries, while no delay was noted in controls (p < 0.0001). Cerebral arteries in BD patients showed lower peak enhancement than controls (34.5 vs. 81.5 HU; p < 0.0001). In all BD patients, CTP revealed zero values of cerebral blood flow and volume. Angiography showed stasis filling in 14 (46.7 %) and non-filling in 16 (53.3 %) cases.

A confrontation of stasis filling with CTP results showed that stasis filling is not consistent with preserved cerebral perfusion, thus does not preclude diagnosis of BD.