A new method for evaluating small intestinal motility using duplex Doppler sonography

Many techniques currently used to study motility of the small intestine are too complex for large-scale use; other techniques provide information that is nonspecific and nonquantitative. The aim of the present study was to verify whether intestinal peristalsis can be seen and quantitatively assessed by means of duplex Doppler sonography.

We prospectively studied 152 normal fasting subjects using sonography, duplex Doppler sonography, and stethoscopic auscultation or phonocardiographic registration of bowel sounds in three abdominal sites. In each subject, we positioned the sample volume near the intestinal wall and then recorded Doppler signals of different amplitude and duration that related to bowel motility. Studies were repeated after ingestion of water (n = 55) and after a standard test meal (n = 73). The number of peristaltic waves and the number of bowel sounds revealed by the different imaging techniques were compared and statistically evaluated by Student's t test.

Intestinal movements were classified as peristaltic or nonperistaltic (mixing movements) based on amplitude and duration of Doppler signals. The mean number of peristaltic waves revealed by Doppler sonography was three per minute in fasting subjects, with no significant increase after ingestion of water (3.78 per min) or the test meal (3.92 per min). The mean number of bowel sounds obtained with auscultation and phonocardiographic recordings was significantly higher in fasting subjects (8.7 per min) and after ingestion of water (9.55 per min) or the test meal (12 per min).

Intestinal contractions produce Doppler signals of different amplitudes and duration, thus potentially allowing differentiation between peristaltic and nonperistaltic movements. This differentiation is not possible with auscultation or phonocardiographic registration because similar bowel sounds are produced by nonprogressive, mixing movements as well as by true peristaltic movements. Duplex Doppler sonography allows graphic visualization of intestinal movements that can be subjected to qualitative and quantitative analysis and may be suitable for the noninvasive study of small-bowel motility.