A simple post mortem room angiography method for the investigation of traumatic basal subarachnoid hemorrhage.

Identifying the site of vascular bleeding in fatal cases of traumatic basal subarachnoid hemorrhage (TBSAH) is important, but can be very difficult to achieve when there is extensive blood clot in the posterior cranial fossa. Post mortem angiography in these circumstances has been reported previously but with mixed results, and is rarely used in current practice within the United Kingdom. We have developed a simple and effective post mortem angiography method, using fluoroscopy and clear modern contrast medium, suitable for use in the autopsy room. Contrast medium was injected through an angiographic catheter positioned (with water filled balloon) in the extracranial vertebral artery (ECVA) just behind the clavicle, whilst the base of the skull and upper cervical spine area was visualized by fluoroscopy following digital subtraction of the bony images. The procedure was developed over a series of 8 TBSAH cases and using unfixed cadaveric specimens. A clear leak point was identified in 3 cases and the likely site indicated in a further fatality (all with tears subsequently confirmed by histology). In 4 cases, the bleeding point was not identified by angiography. In 7 deaths, the anatomy of the upper cervical loops and intracranial course of the vertebral arteries were well delineated by angiography and several small loop segments were documented. In 1 case, with severe degenerative vascular disease, extracranial vessel wall trauma and luminal thrombosis, angiography was unsuccessful above the level of the first cervical (C1) vertebra. Injecting contrast through the internal carotid artery, just above the bifurcation, was also shown to visualize the anterior cerebral circulation well. This method is likely to identify the main site of vascular tearing in about 50% of cases of TBSAH and to delineate the important anatomy of the vessels, prior to dissection of the upper neck and posterior fossa, thus minimizing handling artefacts and guiding the histological sampling of the vessels.

Variations in the anatomy of the vertebral artery cervical loop segment - a potential predisposing factor for traumatic basal subarachnoid hemorrhage?

Fatal traumatic basal subarachnoid hemorrhage (TBSAH) is a characteristic forensic pathological entity, the investigation of which requires special techniques. In Liverpool, post-mortem room angiography is undertaken, followed by complete removal of the vertebral arteries and histological examination. It has been observed that the arterial anatomy can be highly variable, particularly the length and course of the loop segments located between the C2 vertebra and the dura. In a number of cases of TBSAH the loop segments of torn vessels have appeared relatively short. Having observed this phenomenon subjectively in our case work, a radiological study was undertaken with the aim of quantifying vertebral artery loop anatomy variation in a 'normal' population. Multiphase post-mortem computed tomography angiography (MPMCTA) scans of 98 subjects were reviewed and the lengths of the different portions of the loop segments (foramen magnum to the upper border of C1, between C1 and C2, and the bony foramina themselves) of each vertebral artery were measured using semi-automated vessel analysis software. The measurements obtained provide objective evidence of marked anatomical variation, with some loop segments more than twice the length of others. These results are important because a short vertebral artery loop segment might be a significant factor in predisposing an individual to TBSAH following a blow to the head or neck.