Table 3.

Sensitivity, specificity, and positive (PPV) and negative (NPV) predictive values of ultrasound in detecting one or more small bowel strictures at x ray, evaluated in 211 patients undergoing conservative management (non-operative Crohn's disease (CD)) and in 85 patients undergoing surgery (operative CD)

	True positive	True negative	False positive	False negative	Sensitivity (%)	Specificity (%)	PPV (%)	NPV (%)
Non-operative CD patients	59	133	3	16	79	98	95	89
Operative CD patients	63	15	0	7	90	100	100	68