Sonography in acute colonic diverticulitis. A prospective study.

The clinical value of high-resolution real-time sonography for the diagnosis of acute and complicated colonic diverticulitis was prospectively studied in 130 consecutive patients with abdominal complaints, because of which the disease entered into differential consideration. The results of ultrasound investigation were compared with those of clinical examination on admission. Regarding history and initial clinical evaluation, diverticulitis was graded as "highly suspected" in 19 (36.5 percent) out of a total of 52 patients with later proven colonic diverticulitis (prevalence 40 percent), as "possible but equivocal" in 24 (46.2 percent), and as "very unlikely" in the remaining nine (17.3 percent) patients. Ultrasonography enabled the diagnosis of diverticulitis with an overall accuracy of 97.7 percent, a sensitivity of 98.1 percent, and a specificity of 97.5 percent. The predictive values of positive and negative ultrasound examinations were 96.2 percent and 98.5 percent, respectively. The echomorphologic features of acute diverticulitis include visualization of a colon segment presenting with local tenderness on gradual compression, which showed hypoechogenic thickening of the wall and a targetlike appearance in transverse view due to inflammatory changes and muscular thickening. Sonographic signs of peridiverticulitis (hyperechoic halo) were found in 96 percent of patients, echogenic diverticula in 86 percent. Twelve (92 percent) of 13 abdominal abscesses were detected on initial ultrasound examination and could be treated by percutaneous drainage in seven cases, while six required surgical intervention. These results indicate that high-resolution sonography with graded compression is highly sensitive and specific for the imaging diagnoses of acute colonic diverticulitis and complicating abscess.