Sonographic and Doppler assessment of the inferior mesenteric artery: normal morphologic and hemodynamic features

We wanted to evaluate prospectively the feasibility of sonographic and Doppler assessment of the inferior mesenteric artery (IMA) and to provide data on its normal morphological and hemodynamic characteristics.

Sonography and Doppler study of the IMA were performed on 116 patients without splanchnic vessel pathology. Vessel diameter, systolic, diastolic, and time-averaged mean flow velocities, pulsatility index values, and flow volumes were correlated with patient age (< 50 years vs. > or = 50 years) using the Wilcoxon rank-sum test. Findings were verified by splanchnic angiography in 11 cases.

Technically valid studies were obtained in 103/116 cases (88.8%). Flowmetric data showed high peripheral resistance (mean +/- SD: systolic flow velocity, 1.41 m/s +/- 0.48; minimal diastolic flow velocity, 0.10 m/s +/- 0.16; pulsatility index, 3.49 +/- 0.49). Mean flow volume calculated in 80 cases was 0.13 L/min +/- 0.06. Older subjects presented significantly higher time-averaged mean flow velocities and lower resistance than those younger than 50 years.

The success rate for sonographic and Doppler study of the IMA is similar to that observed with larger splanchnic vessels. Knowledge of its normal characteristics is necessary for recognition of pathological conditions and for studies of its physiological behavior.