Doppler US is excellent for classifying stenoses as above or below a single degree of severity but does not function well in stenosis subclassification.

To assess the need for quality control when measuring peak velocities with Doppler ultrasonography, 17 duplex Doppler instruments from six manufacturers were compared by using a flow phantom that had been calibrated for peak velocities ranging from 23 to 75 cm/sec. Variations in peak-velocity measurements among machines averaged 23% when tested at the same flow rate with a Doppler flow phantom, indicating that scientific articles that document peak velocities for various disease processes should be accompanied by equipment calibration data. Doppler string and flow phantoms were compared, and each was found to have deficiencies. Techniques for quality assurance procedures for Doppler measurements are given that should achieve consistent peak-velocity measurements on serial scans of patients undergoing treatment for vascular conditions.

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Small bowel adenocarcinoma develops in 1.5% of patients who have longstanding Crohn disease and is very rarely diagnosed preoperatively because of its rarity, overlapping imaging features, and lack of reported cases. Nonspecific findings including loss of mural stratification (i.e., "target sign") and mild degree of bowel wall enhancement when combined with enlarged mesenteric lymph nodes were helpful computed tomographic findings to suspect malignancy in our case.

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