Fusion of three-dimensional calcium rendering with rotational angiography to guide the treatment of a giant intracranial aneurysm: technical case report.

OBJECTIVE AND IMPORTANCE: Although three-dimensional (3D) rotational angiography enables the visualization of intracranial vascular anatomy with high spatial resolution, its ability to resolve calcified features is limited. We present a case in which a 3D calcium density rendering was fused with rotational cerebral angiography to guide the treatment strategy of a giant, calcified, partially thrombosed, middle cerebral artery bifurcation aneurysm. CLINICAL PRESENTATION: On screening magnetic resonance imaging, a 57-year-old woman with familial subarachnoid hemorrhage was found to harbor a giant trilobed, partially thrombosed, calcified aneurysm. Three-dimensional (3D) cerebral angiography revealed only partial contrast filling of one lobe with a daughter component. TECHNIQUE: A distinct rotational acquisition volume with parameters optimized for calcium density visualization was acquired just before the conventional contrast acquisition. The resulting 3D calcium volume rendering was fused with the vascular model. Multiplanar interactive visualization of the combined model uncovered heavy calcification at the neck of the aneurysm that precluded direct clipping, and the patient underwent endovascular coil embolization. CONCLUSION: Preoperative assessment of intracranial aneurysms can be facilitated by the cunent technique, which enables the detection of calcified tissue near the neck, which would otherwise not be possible with 3D rotational cerebral angiography alone.