Diagnostic Accuracy of Acute Diverticulitis with Non-Enhanced Low-Dose CT

Purpose: To evaluate the diagnostic accuracy of non-enhanced low-dose computed tomography (LDCT) in acute colonic diverticulitis with contrast-enhanced standard-dose CT (SDCT) as the reference method. Materials and Methods: Consecutive patients with clinically suspected diverticulitis were included from two hospitals between January and October 2017. All patients underwent LDCT followed by SDCT. All CT examinations were assessed for signs of diverticulitis, complications, and other diagnoses by three independent radiologists (two radiology consultants and one fourth-year resident) using SDCT as the reference method. Sensitivity, specificity, and agreement were calculated. Results: In total, 149 patients (median age 68, 107 women) were included; 107 had diverticulitis on standard CT. Sensitivity for diverticulitis using LDCT was 100%; the values were 99% for consulting radiologists and 92% for the radiology resident. Specificity was 100% for both consultants and 84% for the resident. Sensitivity for identification of complications was 74%, 60%, and 54%, respectively. Twenty-six patients had other causes of abdominal symptoms on standard CT, 23 (88%) of whom were diagnosed correctly on LDCT. One case of splenic infarction and two cases of segment colitis were missed on LDCT. Conclusion: The diagnostic accuracy of LDCT was high for acute diverticulitis. Therefore, it is recommended as a standard method that should help to reduce radiation dose and cost. LDCT had lower sensitivity for complications, although discrimination between an inflamed diverticulum and small pericolic abscess accounted for a proportion of the discrepancies