Noninvasive diagnosis of small bowel Crohn's disease: combined use of bowel sonography and Tc-99m-HMPAO leukocyte scintigraphy.

Background: Crohn's disease (CD) is frequently localized in the small bowel, with the diagnosis of disease and the assessment of its extension made by ileo-colonoscopy (IC) and small bowel enteroclysis (SBE). Transabdominal bowel sonography (BS) and Tc-99m-HMPAO leukocyte scintigraphy (LS) are increasingly used for the diagnosis of CD because of their minimal invasiveness, reproducibility, and acceptable costs.
Methods: From March 2000 to July 2003, we performed IC, SBE, BS, and LS in 84 patients with either suspected or known small bowel CD.
Results: Small bowel CD was present in 50 patients, whereas the other 34 patients received a different diagnosis. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were, respectively, 98%, 97%, 98%, 97%, and 0.97 for SBE; 92%, 97%, 98%, 88%, and 0.94 for BS; and 90%, 93%, 96%, 85%, and 0.92 for LS. In addition, the combined use of BS and LS led to overall sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of 100%, 93%, 96%, 100%, and 0.97, respectively. BS showed a fair concordance with SBE in terms of location (k = 0.71) and a correlation with the extension of the disease (r = 0.67, P < 0.001). LS showed a concordance with SBE with regard to location in about one-half the population (k = 0.54), whereas it was less effective than SBE in defining disease extension.
Conclusions: BS and LS are 2 accurate techniques for the diagnosis of small bowel CD, and their combined use can be recommended as an early diagnostic approach to patients in which the disease is suspected. SBE remains the best procedure for the definition of the location and extension of the disease.