Comparison of accuracy of magnetic resonance angiography with conventional angiography: a report of 45 cases.

To investigate the accuracy of magnetic resonance angiography (MRA), compared to conventional cerebral and carotid angiography (CA), 45 patients underwent MRA within one week after CA. The MRA involves a FISP (fast imaging steady precession) pulse sequence base on three-dimensional time-of-flight phenomena at 1.0 Tesla. Repetition time of 35-40 msec, echo time of 7-11 msec and a flip angle of 15-25 degrees were used to optimise the depiction of blood flow as high intensity. Volume data were then submitted to a maximum intensity projection programme and viewed at multiple arbitrary projection angles rotating through the three orthogonal planes. Venous structures were suppressed with a presaturation slab superior to the area of interest. All significant stenoses and occlusions at the carotid bifurcation and circle of Willis were detected. Other than the carotid siphon (61.4%), the rest of the arteries have above 70% complete agreement between MRA and CA. The carotid bifurcation and basilar artery show complete agreement of 75.4% and 76.2% respectively, making MRA a simple sensitive screening procedure. This report shows that MR angiography has an important role in the evaluation of blood flow in the head and neck regions.