VALUE OF REPEAT-ANGIOGRAPHY IN CASES OF UNEXPLAINED SUBARACHNOID HEMORRHAGE (SAH)

Purpose - To investigate the rate of false negative initial cerebral a ngiography in spontaneous SAH and to ascertain why aneurysms remain un detected. Furthermore to validate CCT in predicting the presence and s ite of an angiographically missed aneurysm. Methods - Forty-two patien ts with spontaneous SAH were investigated, in whom initial cerebral an giography did not reveal any bleeding cause. Repeat-angiography was pe rformed in all patients 5 to 55 days (mean 15 days) after the bleeding event. All patients underwent CCT scans within 48 h after the ictus. Results - In 8 of 42 patients (19%) repeat-angiography revealed an ane urysm missed on initial angiography. The aneurysms were located on the AcomA (n=2), the MCA (n=2), the ACA (n=1), the PICA (n=2) and the jun ction of ICA and PcomA (n=1). Presumable reasons for missing an aneury sm were spasms detected in four of eight cases on initial angiography and thrombosis of the aneurysm found in two cases at surgery. In two c ases, multiple additional views just revealed the aneurysm appearing d ifferent in size and shape on repeat-angiography. CCT blood distributi on pattern in four cases indicated presence and site of an aneurysm, w hile blood distribution was non-specific in the other four cases. Conc lusion - Repeat-angiography plays an important role in defining the si te of an initially occult aneurysm and should be performed in all case s of unexplained SAH. It is of particular importance if vasospasm has compromised the initial angiogram or if one part of the vascular tree is not optimally seen.