Contribution of MRI and MR angiography in early diagnosis of brain death

Abstract

The objective of this study was to investigate whether the findings of MR imaging and MR angiography could accurately and early diagnose brain death in comatose patients. Thirty comatose patients were studied with MRI and MR arteriography. In 20 patients (group A) presenting with a Glasgow coma scale (GCS) 3-6, the final clinical diagnosis was brain death. In ten comatose patients with a GCS 4-6 and no clinical signs of brain death (group B), the clinical follow-up did not reveal brain death in a period of 12 months. The MRI examination consisted of turbo fluid-attenuated inversion recovery and T2 turbo spin-echo pulse sequences. The MR arteriography was performed with a 3D inflow pulse sequence. In 12 patients with brain death and 5 patients with no signs of brain death, a 3D phase contrast MR venography was also ap-plied. Magnetic resonance imaging in all patients showed variable edema with swelling of the cerebral gyri, small ventricular system, and basilar subarachnoid spaces. In group A, MRI in addition showed tonsillar herniation. In group A, MR arteriography revealed no arterial flow in the intracranial circulation, whereas MR venography showed in 9 patients no opacification of the sagittal and straight sinuses or visualization of intracranial veins. In contrast, MR angiography showed intact intracranial vessels in patients of group B. In conclusion, MR imaging and MR angiography may be reliable ancillary tests for use in early diagnosis of brain death and further work is required to validate its utility.

Gadolinium-enhanced magnetic resonance angiography in brain death

“…In 14 patients the MRA showed no intracranial contrast signal media above the level of the proximal A2-segment of the ACA and the M1-segment of the MCA indicating an irreversible loss of all brain functions (Figure 1). These results are consistent with the findings of several other authors who investigated the intracranial circulation using TOF-based MR angiography262729. No blood flow above the level of the supraclinoid portions of the ICA was found.…”

“…Ishii et al26 suggested first that absence of the cerebral blood flow above the supraclinoid portions of ICA and their intracranial branches on MR angiograms is specific to brain death. Karantanas et al27 and Sohn et al29 confirmed these findings using sophisticated time-of-flight (TOF) imaging techniques. TOF imaging has been increasingly accepted as a technique for the examination of the intracranial circulation.…”

“…Undoubtedly, a total cerebral circulatory arrest documents the “death of all intracranial neurons”124. Various techniques have been used to demonstrate this arrest: four-vessel angiography12, cerebral intravenous digital subtraction angiography9, radionuclide angiography10, single photon emission tomography25, MRI angiography26272829, CT angiography13, and a few more2. Transcranial Doppler sonography (TCD) is a non-invasive technique and is independent from any contrast media.…”

“…It is cost-effective and additionally fast and easy to use on the intensive care unit (ICU)30. Some authors have investigated the reliability of MR angiography262729. Ishii et al26 suggested first that absence of the cerebral blood flow above the supraclinoid portions of ICA and their intracranial branches on MR angiograms is specific to brain death.…”

Imaging Findings of Brain Death on 3-Tesla MRI

“…Other brain MRI and MRA findings of brain death not described here have been well documented as well (10, 18-22), including absent intracranial contrast enhancement, carotid artery enhancement, prominent nasal and scalp enhancement (MR "hot nose" sign), but we did not evaluate them since we did not use intravenous contrast media.…”