In Vitro Evaluation of 2D-Digital Subtraction Angiography versus 3D-Time-of-Flight in Assessment of Intracranial Cerebral Aneurysm Filling after Endovascular Therapy

A, Wide-necked aneurysm filled with colored silicon and coil. Two-micron-thick section preparations (numbered 1–6) were studied via transillumination. B, Enlargement of section 4 (coils, white arrow; colored silicon, black arrow). C, For example, at the level of filling 50%–60%, blue, green, and black silicon were injected (compare Table 2). We then darkened those colors and denoted the open space with gray. At this filling level, the aneurysmal residue on the reference was rated “residual aneurysm” according to the Jean Raymond grading scale.

2D-DSA, wide-neck aneurysm with a partial treatment (residual aneurysm, 50%–60% filling, on the reference) classified as a “residual neck” or “dog ear” by the 2 experts.

2D-DSA imaging of the narrow-necked aneurysm with 90%–100% filling (residual neck on the reference; compare Table 1). A black border is observed around the aneurysm (black arrow). Arterial pulsation may be responsible for misregistration of the mask and the injected series and can mimic a residual neck.

MR 3D-TOF, wide-necked aneurysm with a 30% partial filling (residual aneurysm on the reference; compare Table 2) showing residual flow (arrow) on MIP view (A) and axial reconstructed view (B). C, Residual flow in gray on the reference (arrow) is not observed on 2D-DSA imaging (D).

MR imaging of the wide-necked aneurysm with a loop of coil into the parent artery. The loop is difficult to recognize on MIP view (A) and on source images (B; arrow). 2D-DSA imaging (C) is closely concordant with the reference (D).

Narrow-necked aneurysm (filling 70%–80%, “residual neck,” no silicon protrusion on the reference). A, MR imaging showing the residual neck (white arrow) and the loss of signal intensity around the packing (black arrows). B, 2D-DSA imaging of the same aneurysm.