Interobserver and inter-equipment variability of echo-Doppler sonographic evaluation of the superior mesenteric artery.

ABSTRACT

The aim of this study was to assess the interobserver and inter-equipment variabilities of echo-Doppler sonographic measurement of superior mesenteric artery flow parameters. In the first part of the study the echo-Doppler sonographic parameters (maximum systolic velocity, minimum diastolic velocity, mean velocity, restrictive index, and pulsatility index) were measured independently in nine patients by four skilled operators using four different equipment models. In the second part of the study measurements were taken by the four operators in seven different patients, after one day of cooperative training; the purpose of this part was to define a strict and uniform protocol of Doppler sonographic examination. Significantly different values of maximum systolic velocity, minimum diastolic velocity, mean velocity, and pulsatility index were obtained by the different operators, whereas the inter-equipment variability was significant only for maximum systolic velocity, mean velocity, and pulsatility index. The analysis of the components of variance showed that a large part of this variance was nonsystematic. After training and definition of the protocol no significant differences were found among the operators for any of the parameters, and the 95% confidence limits and coefficients of variation showed a decrease as for maximum systolic velocity, mean velocity, and pulsatility index. This study demonstrates that a significant systematic variability exists among mesenteric Doppler measurements obtained by different operators using different commercially available equipment. Cooperative training can reduce the interobserver variability significantly and bring to an acceptable level the reproducibility of Doppler measurements of superior mesenteric artery flow parameters.