Imaging of intracranial aneurysms and subarachnoid hemorrhage

Advances in CT, MR imaging, and catheter angiography provide the radiologist and neurosurgeon with a variety of imaging options for screening, diagnosis, presurgical evaluation, and postoperative monitoring of patients with intracranial aneurysms. Noninvasive imaging techniques have not replaced conventional angiography for the comprehensive evaluation o aneurysms but are effective in screening patients suspected to have an unruptured aneurysm or for preoperative planning in emergency situations that preclude catheter angiography. CT, CT angiography, MR imaging, and MR angiography can all complement the information obtained with catheter angiography in presurgical planning, and the choice of supplemental studies should be individualized. Rotational and intraoperative angiography are problem-solving options used for selected cases at our institution. Continuous improvements in techniques for CT and MR angiography may someday reach the point where surgery can be undertaken on the basis on noninvasive imaging alone, with catheter angiography reserved for endovascular therapy planning and guidance.