Three-dimensional time-of-flight magnetic resonance angiography as a safe preoperative guide for vertebral arteries in craniovertebral junction anomalies: A cross-sectional study

Introduction: Vertebral artery (VA) anomalies are common in craniovertebral junction (CVJ) anomalies and pose a significant risk for iatrogenic injury during surgery. While computed tomography angiography (CTA) is the reference standard, it involves ionizing radiation and contrast. Three-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA) is a promising noncontrast, radiation-free alternative, yet its diagnostic utility in this specific population remains inadequately validated. The study aimed to evaluate the utility of 3D TOF-MRA for characterizing VA anatomy in CVJ anomalies and to correlate findings with available CTA and operative observations. Materials and Methods: This prospective cross-sectional study included 67 patients with CVJ anomalies. All underwent 3D TOF-MRA on 1.5T/3T scanners. Two radiologists independently analyzed VA course using a modified Sivaraju classification. Available CTA ( n = 10) and operative findings ( n = 7) were reviewed for correlation. Results: 3D TOF-MRA successfully delineated VA anatomy in all patients. Anomalous VA courses were present in 68.7% (left) and 64.2% (right) of patients, with Type 2b being most common. A highly significant association was found between atlanto-occipital assimilation and VA anomalies (100%, P < 0.001), with significant associations also for atlantoaxial dislocation ( P = 0.049) and os odontoideum ( P = 0.039). In all cases with available CTA ( n = 10) and operative correlation ( n = 7), 3D TOF-MRA findings showed 100% concordance. Conclusion: 3D TOF-MRA is a reliable, noninvasive modality for preoperative VA mapping in CVJ anomalies, demonstrating excellent diagnostic concordance with CTA and surgical findings. It offers a safe, effective alternative for preoperative planning, particularly beneficial for younger patients requiring serial imaging.