Visualization of the posterior communicating artery on magnetic resonance angiography

Background: The posterior communicating artery (PComA) is crucial in the formation of the circle of Willis, displaying variations such as hypoplasia and aplasia. These impact collateral blood flow, with false diagnoses, posing risks in pre-surgical planning. Discrepancies between cadaveric and radiological studies highlight the imaging modality precision concerns.Aim: To explore the sensitivity of 3D TOF (time-of-flight) angiograms in visualizing the PComA compared to maximum intensity projection (MIP) tomograms, and to assess whether CE-MRA (contrast-enhanced MRA) improves PComA visualization compared to native MRA.Methods: In this retrospective study there were 137 subjects who underwent MRA between July 2008 and May 2013. Subjects with cerebrovascular disease, vascular malformations and brain tumors were excluded. The study focused on 274 PComA in 137 subjects, evaluating visualization on native and CE-MRA, as well analyzing axial 3D TOF angiograms and MIP images. The analysis categories were: not visualized, poorly visualized or well visualized.Results: Among 211 arteries visualized on CE-MRA, only 2 (0.95%) were not seen on native MRA. CE-MRA, improved visualization in 5.22% of cases, with no significant difference (p=0.99) in PComA visualization between native and CE-MRA. Out of 209 PComA visualized on native MRA, 54 (25.84%) were visible on axial 3D TOF angiograms, but not on MIP reconstructions. Basic 3D TOF tomograms significantly outperformed MIP images (p=0.038) in visualizing PComA.Conclusion: Contrast MRA does not significantly improve the visualization of PComA compared to native MRA, but basic 3D TOF tomograms are significantly better in visualizing PComA compared to MIP reconstructions.