Fenestration of the Coronary Arteries: CT Angiography Findings

Background: Fenestration is a segmental duplication of an artery and is a new entity described in coronary arteries, distinct from dissection. This study aimed to show CT angiography (CTA) findings of fenestrated coronary arteries, along with their possible associations or any accompanying findings. Methods: This was a multicenter study and included examinations from four different institutions. Between the years 2022 and 2025, 5554 patients who underwent coronary CTA without prior coronary catheter angiography and intervention were included in this study. Coronary CTA was acquired using four different multidetector CT scanners. Computed tomography angiography (CTA) examinations were reevaluated for fenestration. Fenestrations were analyzed for morphological type, length, and diameter. Results: In total, 26 of 5554 patients (0.47%) had coronary artery fenestration. Fenestration was observed in 13 left circumflex (Cx) arteries, 8 left anterior descending (LAD) arteries, and 5 right coronary arteries (RCA). Two of the 26 patients underwent catheter angiography. Single-loop-type fenestration was observed in 12 patients, and two patients had multiple-loop fenestrations. There were 12 patients with parallel-type fenestration. Among the patients with fenestrated coronary arteries, myocardial bridging was observed in 5 patients as an associated anomaly. No significant difference was found in the length or diameter of the fenestrated segments. There were no symptoms related to fenestration in our patients. Conclusions: Fenestration of a coronary artery can be demonstrated by CTA and may be associated with myocardial bridging. It is most common in the Cx artery. Fenestration should be differentiated from dissection for clinical implications. Further studies are warranted to understand the importance of this observation.