Hydrocolonic sonography in the evaluation of colonic lesions

The present study was done to assess the sensitivity, specificity, ease of examination, and limitations of hydrocolonic sonography (HCS) to evaluate a heterogeneous spectrum of colonic disorders.

In a prospective study, 100 patients (53 male, 47 female) with clinical suspicion of colonic abnormality were examined by conventional abdominal sonography, HCS, and colonoscopy on the same day. The patients then underwent appropriately planned barium studies. Histopathologic diagnosis was established by colonoscopic/excision biopsies or fine needle aspiration cytology (FNAC) whenever indicated and results correlated.

In 94% of patients, it was possible to evaluate the entire colon from the rectosigmoid junction to the cecum. Redundant parts of the colon were not well evaluated by this technique. The rectum could not be adequately evaluated, and rectal examination was not included in the study. HCS can evaluate in great detail both the colonic lumen and wall and, hence, could suggest the nature of the lesion in the majority (87.9%) of cases based on characteristic changes in wall stratification, echogenicity, lumenal changes, and site and length of involvement, although distinguishing between benign and malignant lesions was not always possible. In 93% of patients with tuberculous colitis/ileocolitis, the normal wall stratification was no longer in evidence, with moderate hypoechoic thickening of the wall (average = 8.34 mm). Malignant lesions (93.7%) showed grossly thickened bowel wall with loss of stratification and hypoechoic/heterogeneous echo texture. Intralumenal polypoid masses also were seen in 87.5% of cases, and there was extension beyond the adventitia and involvement of pericolonic tissues in 75% of cases. All patients with ulcerative colitis had only mild hypoechoic wall thickening; the five-layer structure could be clearly discerned in 87.5% of cases. HCS had an overall sensitivity of 90.9% and a specificity of 94.7% in this study.

HCS can be advantageously used for diagnosis and differential diagnosis of inflammatory and malignant colonic lesions and also for follow-up of patients with chronic inflammatory large bowel diseases such as ulcerative colitis.