Diagnostic value of CTA and MRA in intracranial traumatic aneurysms

To investigate the diagnostic value of computerized tomographic angiography (CTA) and magnetic resonance angiography (MRA) for intracranial traumatic aneurysms (TAs).

CTA and MRA of six patients with intracranial TAs verified by digital subtraction angiography (DSA) and surgery were retrospectively analysed. All patients were examined by nonenhanced computerized tomography (CT) and two by CTA. The source data were reconstructed by volume rendering (VR) and multi-planar reconstruction (MPR) from CTA. Four of them had maximum intensity project (MIP) from MRA.

Of the six patients, a total of seven TAs were detected by CTA and MRA examinations. Five cases had only one TA and one case had two TAs. The average diameter was 2.3 cm (1.1-3.3 cm). CTA demonstrated two TAs appeared at the cavernous segment of the internal carotid artery (ICA) and the middle cerebral artery (MCA) respectively. MCA TA was definitely and clearly demonstrated on VR images, whereas VR images failed to depict the cavernous ICA TA, which was detected on MPR images. Two TAs were found irregular saccular shape, irregular margin of parent artery and wide neck on CTA. Four MRA examinations demonstrated five TAs, including the cavernous segment ICA TAs (2 cases), the supraclinoid segment ICA TA (1 case), and the cavernous segment associated with opposite side of the petrosal segment ICA TA (1 case). In a cavernous ICA TA, MRA only revealed aneurysm body, whereas aneurysm neck and distal segment of the parent artery were not revealed. In the remaining cases, MRA clearly depicted aneurysm body and parent artery, whereas the neck was not displayed. ICA TAs showed irregular capsule-like high signal intensity on MRA images. Four TAs exhibited irregular distal segment of the parent artery. TAs at the supraclinoid segment or MCA failed to find fracture signs on nonenhanced CT.

Both CTA and MRA examinations are the effective non-invasive method of imageology for diagnosing intracranial TAs, while CTA is more eligible for diagnosing TAs after nonenhanced CT has demonstrated skull base fractures.