Frequency of Aneurysmal Subarachnoid Hemorrhage in Perimesencephalic Subarachnoid Hemorrhage and Need of 4-vessel Angiography

ABSTRACT

OBJECTIVE: In this study, each of the frequency of nonaneurysmal perimesencephalic subarachnoid hemorrhage(N-PMSH), and the clinical and radiologic features, incidence and location of aneurysmal perimesencephalic subarachnoid hemorrhage(A-PMSH), based on aneurysmal rupture and nonaneurysmal subarachnoid hemorrhage in patients with spontaneous subarachnoid hemorrhage, are investigated for clinical application. METHODS: Patients who showed perimesencephalic subarachnoid hemorrhage, among the 388 patients with subarachnoid hemorrhage admitted into the our hospital from March 1994 to November 2002, were extracted ; and their charts and angiographies were examined retrospectively. They were divided into two groups - aneurysmal perimesencephalic subarachnoid hemorrhage group and nonaneurysmal perimesencephalic subarachnoid hemorrhage group - and comparative analysis was conducted on the clinical patterns and radiologic characteristics of each group. RESULTS: There were 22 patients(5.68%) with perimesencephalic subarachnoid hemorrhage(PMSH) among 388 patients with spontaneous subarachnoid hemorrhage. Of the 22 PMSH, 8 patients(36%) were aneurysmal PMSH(A-PMSH), 14 patients(64%) were nonaneurysmal PMSH(N-PMSH). N-PMSH occurred not only in the posterior circulation(5 cases), but also in the anterior circulation(3 cases). There was no difference in the CT features of PMSH between aneurysmal and nonaneurysmal cause. CONCLUSION: According to the above results, 4-vessel angiography is essential for patients with perimesencephalic subarachnoid hemorrhage, and CTA and MRA can be used as assisting diagnosis methods.