Purpose: We investigated the relationship between ultrasound findings, inflammatory markers, and the severity of diverticulitis in colorectal diverticulitis patients.

Subject and method: We enrolled 98 patients diagnosed with colorectal diverticulitis by abdominal ultrasound in our clinic. Based on the ultrasound findings we classified them into three grades of severity and compared their sex age, location of diverticulitis, inflammatory data (white blood cell count [WBC], C-reactive protein [CRP]), computed tomography (CT) findings, and clinical course.

Results and considerations: Of the 98 cases, there were 29, 60, and 9 classified as Grades 1, 2, and 3, respectively. There was no significant difference in sex, age or the location of the diverticulitis. The average WBC count and average CRP level were 8907/µL and 3.2 mg/dL, respectively, in the Grade 1 group, 11205/µL and 5.9 mg/dL, respectively, in the Grade 2 group, and 13122/µL and 11.0 mg/dL, respectively, in the Grade 3 group. There was a significant difference in the WBC average (p＝0.0001) and CRP (p＝0.00004). The value of the kappa coefficient between ultrasound findings and CT findings in the Grade 3 group was as follows: 0.25 in cases with abscess, 0.55 in cases with retroperitoneal gas, and 0.00 in cases with diverticular wall interruption. There were 5 cases (17%) in the Grade 1 group, 32 cases (53%) in the Grade 2 group, and 9 cases (100%) in the Grade 3 group, who were hospitalized for treatment.

Conclusion: Grading according to ultrasound findings in patients with colorectal diverticulitis correlated with inflammatory data and the severity of diverticulitis. This is a useful indicator on which to base treatment.