Computerized tomography angiography in isolated third nerve palsies.

OBJECT: The goal of this study was to assess the value of computerized tomography (CT) angiography as a diagnostic tool in isolated oculomotor nerve palsies.
METHODS: One hundred consecutive patients who presented with an isolated third nerve palsy were examined by CT angiography. This procedure was followed by conventional cerebral angiography in most patients in whom a vascular abnormality was noted on the CT angiography. Thus, all patients whose symptoms were caused by a compressive aneurysm were identified. The remaining patients were observed clinically to exclude the possibility that a missed cerebral aneurysm caused the isolated third nerve palsy. Eighteen patients harbored a cerebral aneurysm responsible for causing the isolated third nerve palsy. Most of the remaining patients experienced some degree of spontaneous recovery. There was no clinical evidence to indicate that a case of compressive cerebral aneurysm causing the isolated third nerve palsy had been missed on CT angiography.
CONCLUSIONS: Computerized tomography angiography is a reliable diagnostic tool for use in the assessment of patients with an isolated third nerve palsy; it can identify the minority of patients in whom conventional cerebral angiography may be required.