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(Stroke. 1999;30:1974-1981.)
© 1999 American Heart Association, Inc.

Letters to the Editor

Perimesencephalic Hemorrhage

Harry J. Cloft, MD, PhD

Interventional Radiology, Radiology Department, Emory University Hospital, Atlanta, Georgia

Key Words: cerebral aneurysm • angiography, digital subtraction • tomography, x-ray computed

	Introduction

 
To the Editor:

The article by Velthuis et al¹ in the May 1999 issue of Stroke was an interesting case series, but I feel that their results do not logically lead to their conclusions. A small series of 16 patients with perimesencephalic hemorrhage with no aneurysm detected on CT angiography or digital subtraction angiography (DSA) does not prove that CT angiography alone is adequate for the detection of cerebral aneurysms in patient with perimesencephalic subarachnoid hemorrhage.

Velthuis et al¹ are proposing that CT angiography is an adequate screening examination for cerebral aneurysms in patients with perimesencephalic hemorrhage. The most important issue in a screening study is sensitivity, not specificity. In their discussion, Velthuis et al point out that the specificity of CT angiography for the detection of cerebral aneurysms is 89% to 100%, according to a number of references.^{2 3 4 5 6 7 8 9} They do not discuss the fact that the sensitivity of CT angiography in these studies ranged from 67% to 96%.^{2 3 4 5 6 7 8 9} In fact, Velthuis et al reported in a study⁵ that CT angiography at their institution depicted 90% of aneurysms confirmed with DSA. One must assume that this 90% sensitivity of CT angiography at their institution also applies to vertebrobasilar aneurysms in patients with perimesencephalic hemorrhage. If one fails to detect 10% of aneurysms that present with the perimesencephalic hemorrhage pattern, and 5% of patients with this pattern actually have an aneurysm,¹ a ruptured aneurysm will not be detected in about 0.5% of cases. The risk of rebleeding from a ruptured aneurysm . . . [Full Text of this Article]

Gabriel J.E. Rinkel, MD Birgitta K. Velthuis, MD

University of Utrecht, Utrecht, the Netherlands