Usefulness of Ultrasonography for Diagnosis of Small Bowel Tumors: A Comparison Between Ultrasonography and Endoscopic Modalities

Ultrasonography is a standard, noninvasive modality used to evaluate patients with gastrointestinal diseases. This study assessed the usefulness of ultrasonography in the detection of small bowel tumors. This study enrolled 558 consecutive patients (295 males, 263 females; mean age 71.1 years) who underwent ultrasonography before capsule endoscopy and/or balloon-assisted endoscopy. Ultrasonographic detection of small bowel tumors was compared with detection by capsule endoscopy and/or balloon-assisted endoscopy. In addition, factors affecting small bowel tumor detection by ultrasonography and clinical characteristics of patients with small bowel tumors undetected by ultrasonography were evaluated. Ninety-seven tumors (52 benign, 45 malignant) detected by capsule endoscopy and/or balloon-assisted endoscopy were retrospectively analyzed. The sensitivity and specificity of ultrasonography in the detection of small bowel tumors were 50.5% (47/93) and 100% (465/465), respectively. If we restricted patients to those with a tumor >20 mm in size, its detection ratio would become higher (91.7%): the ratio of submucosal tumor >20 mm in size was 85.7% (6/7) and that of partial and circumferential ulcerative tumors >20 mm in size was 96.9% (31/32), respectively. Small bowel tumors detected by ultrasonography (mean 33.2 mm) were significantly larger than those undetected by ultrasonography (mean 8.7 mm). The percentage of small bowel tumors located in the ileum detected by ultrasonography (70.6%) was significantly higher than those undetected by ultrasonography (29.4%). Of the 46 small bowel tumors undetected by ultrasonography, 42 (91.3%) were benign tumors with good clinical prognosis. Ultrasonography is a useful modality for detecting larger small bowel tumors and ulcerative lesions. Ultrasonography should be considered a first-line modality for patients suspected of having small bowel tumors, because most small bowel tumors undetected by ultrasonography were benign tumors with good clinical prognosis.