Detection of Aneurysms by 64-Section Multidetector CT Angiography in Patients Acutely Suspected of Having an Intracranial Aneurysm and Comparison with Digital Subtraction and 3D Rotational Angiography

A 47-year-old woman with SAH and multiple 4- to 10-mm aneurysms; aneurysm measurement technique is demonstrated. MSCTA showed 3 aneurysms: a 7 mm basilar tip aneurysm (arrowhead, A), a right posterior communicating artery (PcomA) segment aneurysm (solid arrow, A), and a fenestrated, fusiform anterior communicating artery (AcomA, dashed arrow, A). Sectioned 3D (B, top) and MPR (B, bottom) images were used to measure the PcomA aneurysm. 3DRA demonstrated the PcomA (gold arrow denotes the site of hemorrhage, C) and the double-fenestration AcomA (dashed red arrows, C).

A 78-year-old woman with SAH from an aneurysm more than 10 mm in size. MSCTA showed a 12-mm aneurysm in the periophthalmic ICA segment on 3D-VR images (data not shown), with peripheral calcifications, best seen on MPR (short white arrows, A). The aneurysm was noted to be separate from the ophthalmic artery origin on 3DRA (black arrow, B).

The only false-negative CTA, in a 72-year-old man with severe headache, lacking hemorrhage on CT. However, the symptoms prompted an MR imaging/MR angiography (data not shown), with tiny infarcts and a questionable left supraclinoid ICA outpouching. Thereafter, the patient underwent catheter DSA to exclude vasculitis (which was negative), which showed a 2-mm periophthalmic aneurysm on 3DRA (dashed arrow, A). Closer, repeat review of the CTA showed the lesion projecting medially over the bony sella (arrow, B).

The only false-positive CTA. A 38-year-old woman with confusion had a head CT negative for hemorrhage but with an isoattenuated structure in the region of the left MCA (data not shown) and corresponding flow void on T2-weighted MR imaging (data not shown), suspicious for aneurysm. Both 16-section (data not shown) and repeat 64-section CTA were performed, which showed a bizarre 6- to 7-mm outpouching (question marks, A and B) overlying the left MCA bifurcation on MPR axial (A, top) and coronal (A, bottom) and 3D MIP/VR posterior (B, top) and superior (B, bottom) views. This was considered a prominent middle cerebral venous plexus, because the catheter DSA and 3DRA (data not shown) were completely negative.

Blisterlike lesion in a 46-year-old man with SAH from a 3.5-mm MCA aneurysm, noted on CTA and 3DRA (asterisk, A). The sessile lesion was noted on the undersurface of the ICA and not noted on CTA 3D-VR (data not shown) or MPR (B) views. This was not changed on 2-week repeat catheter 3DRA.