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Fig 5. 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.
