Evaluation of short axial blood flow pattern in thoracic descending aorta by use of tagging cine magnetic resonance.

The authors, for the first time, evaluated the short axial blood flow profile by using tagging cine magnetic resonance (MR). Cine MR was performed on 15 healthy volunteers aged 51.5 +/- 23.1 (SD) years. The transverse plane of the thoracic descending aorta was imaged at the middle level of the left ventricle. Two or four radial tags, whose thickness was 3 mm width each, were established to the short axial image of the descending aorta at 2 msec and 300 msec following the R wave of the subjects' QRS complex on the electrocardiogram. They observed the flow patterns and measured the rotating flow velocity of the thoracic descending aorta in early systole and late systole from the following formula: v = d/t, (v = velocity, d = displacement of tags over the interval, t = time interval between the time of presaturation and the time of imaging). In the short axial image of the descending aorta, 13 subjects showed the clockwise rotation of tags in the supine position from the foot side view. Flow image of the other 2 subjects showed as undefined. Rotating flow velocity was 1.63 +/- 0.88 cm/sec in early systole and was 1.37 +/- 1.11 cm/sec in late systole. Tagging cine MR is useful to evaluate the blood flow profile in the thoracic descending aorta.