[Clinical application of phase contrast angiography]

"Phase Contrast Angiography" is a new technique of Magnetic Resonance Angiography as reported by Dumoulin CL et al. Using this technique, we can obtain images of vessels (angiograms) without injection of contrast medium. We present the results of phase contrast angiography on cerebral and spinal vascular disease. We utilized the General Electric SIGNA, 1.5 tesla NMR. One hundred and ninety-one cases of cerebral and spinal vascular diseases were scanned using phase contrast angiography. Included were 90 cases of occlusive vascular disease, 16 cases of moyamoya disease, 39 cases of arteriovenous malformation, and 28 aneurysms. The phase contrast angiography uses flow encoding gradient pulses, which impart a velocity-dependent phase shift to the transverse magnetization of moving spins. The resulting image contains only information from the moving spins; while information from stationary tissue remains suppressed. In cases using 3-D angiogram, we made 32 images 6 degrees apart in their projection direction and displayed them on a video terminal. We were able to visualize occlusions of vessels, aneurysms, bypassed vessels, and abnormal vessels of arteriovenous malformations. Retrospective evaluation comparing phase contrast angiography with conventional angiography of the stenotic findings on the horizontal portion of middle cerebral arteries (64 vessels of 32 patients), resulted in a false positive ratio of 39.1%. We obtained clinically valuable results regarding the hydrodynamics of patients using "phase contrast angiography" non-invasively. These results reveal not only "anatomical" images of vessels, but also "functional" images, which are sensitive to the pattern of the blood flow. This study would strongly suggest that phase contrast angiography presents a valuable tool for the clinical diagnosis of cerebral and spinal vascular diseases.