Blood Flow Mimicking Aneurysmal Wall Enhancement: A Diagnostic Pitfall of Vessel Wall MRI Using the Postcontrast 3D Turbo Spin-Echo MR Imaging Sequence

Abstract

Our aim was to compare the detectability of aneurysmal wall enhancement in unruptured intracranial aneurysms between conventional and motion-sensitized driven equilibrium-prepared postcontrast 3D T1-weighted TSE sequences (sampling perfection with applicationoptimized contrasts by using different flip angle evolution, SPACE). Twenty-two patients with 30 unruptured intracranial aneurysms were scanned at 3T. Aneurysmal wall enhancement was more significantly detected using conventional compared with motion-sensitized driven equilibrium-prepared SPACE sequences (10/30 versus 2/30, P < .0001). Contrast-to-noise ratio measurements did not differ between conventional and motion-sensitized driven equilibrium-prepared sequences (P = .51). Flowing blood can mimic aneurysmal wall enhancement using conventional SPACE sequences with potential implications for patient care.

Fig 1.

Saccular intracranial aneurysm in a 63-year-old patient. DSA angiogram (A, from left to right: early arterial phase, arterial phase, and venous phase) shows a 14-mm right internal carotid artery aneurysm with intrasaccular slow flowing/stagnant blood (arrowheads) and irregular shape (arrow). With conventional SPACE imaging (B), extensive AWE is visible, more prominent at the apex and at the lateral portion of the aneurysm (B, arrows). Note the enhancement within the aneurysm lumen visible only using conventional SPACE imaging (B, arrowhead), matching the stagnant blood on DSA (A, arrowheads). With MSDE SPACE imaging, AWE is only visible at the apex (C, arrow).

Fig 2.

Saccular intracranial aneurysm in a 42-year-old patient. DSA angiogram shows an 11-mm aneurysm (A, star) arising from the M1 segment of the right middle cerebral artery. AWE is visible on the conventional SPACE image (B, arrow), while there is no enhancement visible on the corresponding MSDE SPACE image (C). Enhancement within the aneurysm lumen was also visible using a conventional SPACE image (B, arrowhead).