Ultrasonography of colon by conventional abdominal approach is frequently frustrating. Hydrocolonic sonography [HCS] is a development of the conventional ultrasonographic examination of abdomen that has recently been shown to be effective in assessing the colon wall, lumen, and surroundings.

Patient is instructed to eat an exclusively low-residue diet during the previous day of examination. On the next morning, after bowel moved, the patient comes to the centre in empty stomach. At the centre, enema simplex with warm soap-water is given. No significant adverse effects are noted during or after colon cleaning. The whole colon up to caecum can be examined in most of the cases without any difficulty.

Normal colon: The thickness of the colon wall is 3±1 mm. Within the colon wall, five layers of different echogenicity are sonographically demonstrated. Colon polyp: Colon polyps appear sonographically as echogenic structures that project into the colon lumen and float in the lumen. Colon carcinoma: Colon carcinomas appear as rounded echogenic structures that project into the lumen. In contrast to polyps, these have no observable movement in the intestinal lumen. Sometimes the whole circumference of the colon wall is involved. In favorable examination conditions, sonographic demonstration of colon wall infiltration is detected. Crohn's disease: In patients with active Crohn's disease, the intestinal wall is thickened up to 10mm, as well as the loss of haustrations. The luminal border is less echogenic and further distinction of other intestinal wall layers is no longer possible. Ulcerative colitis: In patients with ulcerative colitis, bowel wall is thickened approximately 5±1mm. The five-layer structure remained intact. Colon tuberculosis: Hypertrophic type of caecal tuberculosis is presented as gross thickening and total destruction of the colon wall. Lymph nodes involvements are present.

Hydrocolonic sonography is an alternate modality of imaging the colon. In fact, relatively less attention has been paid on this promising method of examining colon. It is a cheap, rapid and well-tolerated procedure. In a country like Bangladesh, this procedure can he applied without involving significant amount of extra money and man-power.