Dissecting aneurysm of the vertebral artery. Report of seven cases and angiographic findings.

Seven cases of dissecting aneurysm of the vertebral artery, all appearing to be of fusiform type, are reported. Clinically, all seven cases initially showed symptoms of subarachnoid hemorrhage; however, three of these were associated with Wallenberg's syndrome. The characteristic angiographic findings in these cases were: 1) retention of contrast medium in the aneurysm; 2) the presence of a true (vertebral artery) and false (arterial wall) lumen in the late arterial and/or venous phase; and 3) irregular arterial narrowing proximal and/or distal to the aneurysm. Autopsy findings of one patient supported the angiographic findings. Recently, reports of fusiform aneurysms associated with subarachnoid hemorrhage have been increasing. As dissecting aneurysms are found in the fusiform group, it is very important to analyze serial angiograms in order to choose a method of surgical treatment.