Complementary use of computed tomographic angiography in treatment planning for posterior fossa subarachnoid hemorrhage.

OBJECTIVE

The goal of this study was to determine whether the complementary use of computed tomographic angiographic (CTA) assessments would provide additional benefits in the evaluation and treatment of ruptured vertebrobasilar artery aneurysms.

METHODS

In the past 4.5 years, 35 patients with an infratentorial dominant pattern of subarachnoid hemorrhage were complementarily examined with CTA scanning, after undergoing one or more three-dimensional rotational projection digital subtraction angiographic (DSA) studies. The results of these studies were interpreted by the treating neurosurgeon and an interventional radiologist, to examine the usefulness of the findings for the detection of aneurysms and to determine the grade of parent artery vascular filling and the optical definition of the aneurysm. This information provided additional benefits for case management.

RESULTS

Thirty-three aneurysms were detected. For 10 patients, no aneurysm was identified in repeated examinations with the two methods. We detected only 16 of the 25 ruptured aneurysms (64%) on the first DSA scans and, even with repeated examinations, 6 aneurysms were not clearly identified with this technique. CTA scanning revealed the ruptured aneurysms in 25 cases and demonstrated increased vascular filling and improved optical definition of the aneurysms, compared with DSA scanning, in 12 cases (48%). The information obtained from the CTA scans allowed the selection of five patients for endovascular treatment and facilitated the surgical procedures in five cases.

CONCLUSION

Complementary CTA examination of the vertebrobasilar complex provides a higher rate of aneurysm detection and improves the optical definition and anatomic projection of these aneurysms, compared with DSA scanning alone. This facilitates therapeutic decision-making (surgical versus endovascular procedures) and allows neurosurgeons to use more restricted surgical exposures.