High-resolution magnetic resonance angiography of the rat brain: detection of Cerebral vasospasms in subarachnoid hemorrhage models

In this study, we detected cerebral vasospasms following subarachnoid hemorrhages (SAH) in rats using high-resolution magnetic resonance (MR) angiography. Measurements were performed using a 4.7 T MR imaging system with a 26-mm radiofrequency coil. Cerebral arteries were visualized based on the time-of-flight method. Optimization studies for the repetition time (TR) and the flip angle were performed to yield the best detection of the circle of Willis and the main cerebral arteries. The optimum image contrast was obtained with a TR of 60 ms and a flip angle of 60°. The SAH was induced by intracisternal injection of autologous blood, and MR angiograms were obtained 7 days after the injection. The cerebral vasospasms following the SAH caused a decrease in the diameter of arteries. A decrease in the signal intensity of MR angiogram was observed in the main cerebral arteries due to the decrease in the diameter.