Fig 2. A 47-year-old man with chronic headache. A left, unruptured middle cerebral artery (MCA) aneurysm was suspected during routine CT, which motivated high-resolution CT angiography (HCRTA). HRCTA revealed a 6-mm MCA aneurysm, which pointed inferiorly and was embedded in the temporal lobe (A–D). The whole circumference of the aneurysm was surrounded by brain tissue, resulting in a balanced contact constraint (A–C). This aneurysm had regular contours.

A–C, Sequential, coronal plane, multiplanar reconstructions of HRCTA. arrows, balanced contact constraint with surrounding temporal lobe parenchyma.

D, Three-dimensional reconstruction of HRCTA, left superior view. A, MCA aneurysm; asterisk, posterior clinoid process.