High‐resolution contrast‐enhanced magnetic resonance angiography of the carotid arteries using fluoroscopic monitoring of contrast arrival: diagnostic accuracy and interobserver variability

Abstract

Purpose: To evaluate the diagnostic accuracy of high‐resolution contrast‐enhanced magnetic resonance angiography (CE‐MRA) of the supra‐aortic arteries using the CareBolus technique. Digital subtraction angiography was the standard of reference. Material and Methods: Fifty consecutive patients with suspected internal carotid artery stenosis underwent CE‐MRA and digital subtraction angiography. CE‐MRA was performed on a 1.5‐T superconducting scanner with the CareBolus technique. CareBolus combines a nearly real‐time 2D‐FLASH (fast low angle shot) sequence for fluoroscopic triggering and a high‐resolution 3D‐FLASH with elliptical centric view order for the angiographic pulse sequence (6.0/2.16 ms [TR/TE], 30° flip angle, 30.98 s acquisition time, 0.88 mm effective (interpolated) partition thickness and a 160×512 matrix). Intra‐arterial digital subtraction angiography and CE‐MRA studies were evaluated independently by four blinded readers. Internal carotid artery stenoses were graded according to the NASCET criteria. Results: CE‐MRA had an accuracy of 92.53%, a sensitivity of 95.64%, and a specificity of 90.39% for the identification of carotid artery stenoses ≥70% (grade 3). Image quality for suppression of stationary tissue and venous contrast was good, but was reduced in five cases due to patient motion. Conclusion: The CareBolus technique is a useful non‐invasive method for high‐resolution imaging of the supra‐aortic vessels because of its easy application and high sensitivity and specificity. Limitations can occur in non‐compliant patients due to motion artifacts during the measurement time.