Carotid artery: Elliptic centric contrast-enhanced MR angiography comparedwith conventional angiography

PURPOSE: To determine the accuracy of elliptic centric contrast material-en hanced magnetic resonance (MR) angiography by using conventional angiograph y as the reference standard. MATERIALS AND METHODS: Fifty patients were examined prospectively with cont rast-enhanced MR angiography and conventional angiography. The two examinat ions were performed within 1 week of each other. Two patients underwent con ventional angiography of only one carotid artery, which yielded 98 arteries for comparison. RESULTS: With conventional angiography as the reference standard and by usi ng a 70% threshold for internal carotid arterial diameter stenosis, maximum intensity projection (MIP) images had a sensitivity of 93.3%, specificity of 85.1%, and accuracy of 87.6%, whereas reformatted transverse source imag es had a sensitivity of 83.3%, specificity of 97.0%, and accuracy of 92.8%. Interobserver variability for conventional angiograms was 0.97, for MIP im ages was 0.91, and for source images was 0.90. The contrast-enhanced MR ang iographic technique had a sensitivity of 88.9% and specificity of 58.1% for the presence of irregularity and/or ulceration. All 50 examinations were t riggered appropriately so that minimal or no venous signal intensity was de picted. CONCLUSION: Contrast-enhanced elliptic centric three-dimensional MR angiogr aphy offers high-spatial-resolution, venous-suppressed images of the caroti d arteries that appear to be adequate to replace conventional angiography i n most patients examined prior to carotid endarterectomy.