The preoperative evaluation of patients with
intracranial aneurysms typically includes a contrast-enhanced vascular study, such as computed tomography angiography (CTA), magnetic resonance angiography (MRA), or digital subtraction angiography. However, there are numerous absolute and relative
contraindications to the administration of imaging
contrast agents, including pregnancy, severe contrast
allergy, and
renal insufficiency. Evaluation of patients with contrast
contraindications thus presents a unique challenge. We identified three patients with absolute contrast
contraindications who presented with
intracranial aneurysms. One patient was pregnant, while the other two had previous severe
anaphylactic reactions to iodinated contrast. Because of these
contraindications to intravenous contrast, we performed non-contrast time-of-flight MRA with 3D reconstruction (TOF MRA with 3DR) with maximum intensity projections and volume renderings as part of the preoperative evaluation prior to successful open surgical clipping of the
aneurysms. In the case of one paraclinoid
aneurysm, a high-resolution non-contrast CT scan was also performed to assess the relationship of the
aneurysm to the anterior clinoid process. TOF MRA with 3DR successfully identified the
intracranial aneurysms and adequately depicted the surrounding microanatomy. Intraoperative findings were as predicted by the preoperative imaging studies. The
aneurysms were successfully
clip-obliterated, and the patients had uneventful post-operative courses. These cases demonstrate that non-contrast imaging is a viable modality to assess
intracranial aneurysms as part of the surgical planning process in patients with contrast
contraindications. TOF MRA with 3DR, in conjunction with high-resolution non-contrast CT when indicated, provides adequate visualization of the microanatomy of the
aneurysm and surrounding structures.