Doppler waveforms of the normal and collateralized inferior mesenteric artery

OBJECTIVE. Our purpose was to analyze Doppler waveform changes and the caliber of the inferior mesenteric artery as a collateral vessel in occlusive disease of the abdominal aorta or its main branches. SUBJECTS AND METHODS. Thirty-three patients were examined in three groups according to the location of their occlusive disease (group 1 [n = 5], occlusion of the celiac and superior mesenteric arteries; group 2 [n = 9], occlusion of the iliac artery; and group 3 [n = 19], occlusion of the abdominal aorta distal to the renal arteries). The main truncus of the inferior mesenteric artery was evaluated along its longitudinal axis using color duplex Doppler sonography. Peak systolic velocity, end-diastolic velocity, mean velocity, resistive index, and pulsatility index were determined from the Doppler spectrum. The inner diameter and cross-sectional area of the inferior mesenteric artery were measured, and blood flow volume was calculated. The data obtained from the three groups were compared with data from a control group (n = 24), RESULTS. In all three patient groups, the mean blood flow volume and the mean flow velocities were significantly higher, the mean pulsatility index was significantly lower, and the mean diameter of the vessel was significantly larger than in the control group. The blood flow volume in patients with aortic occlusion was significantly lower than that in patients with superior mesenteric artery occlusion. Ln the patients with iliac artery occlusion, the mean resistive index was not significantly different from that in the control group. CONCLUSION. An increase in blood flow volume and the presence of a monophasic waveform indicate increased collateral function of the inferior mesenteric artery. However, blood flow volume in patients with aortic occlusion does not increase as high as in patients with superior mesenteric artery occlusion, and a monophasic waveform is not a distinctive finding in iliac artery occlusion.