Accuracy of “TICS” ultrasound protocol in detecting simple and complicated diverticulitis: A prospective cohort study

Abstract

Background Point‐of‐care ultrasound (US) has been suggested as the primary imaging in evaluating patients with suspected diverticulitis. Discrimination between simple and complicated diverticulitis may help to expedite emergent surgical consults and determine the risk of complications. This study aimed to: (1) determine the accuracy of an US protocol (TICS) for diagnosing diverticulitis in the emergency department (ED) setting and (2) assess the ability of TICS to distinguish between simple and complicated diverticulitis. Methods Patients with clinically suspected diverticulitis who underwent a diagnostic computed tomography (CT) scan were identified prospectively in the ED. Emergency US faculty and fellows blinded to the CT results performed and interpreted US scans. The presence of simple or complicated diverticulitis was recorded after each US evaluation. The diagnostic ability of the US was compared to CT as the criterion standard. Modified Hinchey classification was used to distinguish between simple and complicated diverticulitis. Results A total of 149 patients (55% female, mean ± SD age 58 ± 16 years) were enrolled and included in the final analyses. Diverticulitis was the final diagnosis in 75 of 149 patients (50.3%), of whom 53 had simple diverticulitis and 22 had perforated diverticulitis (29.4%). TICS protocol's test characteristics for simple diverticulitis include a sensitivity of 95% (95% confidence interval [CI] 87%–99%), specificity of 76% (95% CI 65%–86%), positive predictive value of 80% (95% CI 71%–88%), and negative predictive value of 93% (95% CI 84%–98%). TICS protocol correctly identified 12 of 22 patients with complicated diverticulitis (sensitivity 55% [95% CI 32%–76%]) and specificity was 96% (95% CI 91%–99%). Eight of 10 missed diagnoses of complicated diverticulitis were identified as simple diverticulitis, and two were recorded as negative. Conclusions In ED patients with suspected diverticulitis, US demonstrated high accuracy in ruling out or diagnosing diverticulitis, but its reliability in differentiating complicated from simple diverticulitis is unsatisfactory.

Accuracy of diagnostic tests for acute diverticulitis that are feasible in primary care: a systematic review and meta-analysis

“…Fifteen studies included patients prospectively and two studies retrospectively. 19 , 20 The majority of studies were performed in Europe (twelve studies, N = 4,372, 510 cases), 18 , 21–31 the rest was performed in Asia (two studies, N = 283, 86 cases) 19 , 32 and North America (three studies, N = 672, 282 cases) 20 , 33 , 34 ( Supplementary material 4 ). The prevalence of acute diverticulitis in the populations ranged from 11% to 65% (median 48%, IQR 37–58).…”

“…Table 1 presents the risk of bias in the included studies. Ten studies were assessed as demonstrating a high risk of bias in ≥1 domains, 19–21 , 23 , 24 , 27 , 28 , 31 , 33 , 34 and fourteen studies scored unclear risk of bias in ≥1 domains 19 , 20 , 22–33 ( Table 1 ). High risk of bias in the domain patient selection was related to inappropriate exclusions in two studies.…”

“… 19 , 21 The domain index test was scored high risk of bias in two studies, because the index test results were interpreted with knowledge of the reference standard, 30 or the threshold was not pre-specified. 23 Six studies scored high risk of bias for the domain reference standard since the studies had only used CT as a reference standard, 33 , 34 and/or the reference standard was interpreted with knowledge of the index test. 20 , 23 , 27 , 31 , 33 , 34 Four studies scored a high risk of bias for domain flow and timing because not all patients were included in the analysis, 26 , 34 or the time interval between the index test and the reference standard was either too long 20 or too short.…”

“… 23 Six studies scored high risk of bias for the domain reference standard since the studies had only used CT as a reference standard, 33 , 34 and/or the reference standard was interpreted with knowledge of the index test. 20 , 23 , 27 , 31 , 33 , 34 Four studies scored a high risk of bias for domain flow and timing because not all patients were included in the analysis, 26 , 34 or the time interval between the index test and the reference standard was either too long 20 or too short. 28 Applicability concerns were low in all domains for four studies.…”

“… The table is presented without the incorporation of differential verification bias, because almost all studies scored a high risk of differential verification bias, except the studies of Cohen et al 33 and Shokoohi et al 34 . a First row of Andeweg et al 21 is the risk of bias for signs and symptoms, second row for blood tests.…”