Objective To determine whether clinical scoring systems or physician gestalt can obviate the need for CT in patients with possible appendicitis. Methods Prospective, observational study of patients with abdominal pain at an academic emergency department from 2/2012–2/2014. Patients over 11 years old who had a CT ordered for possible appendicitis were eligible. All parameters needed to calculate the scores were recorded on standardized forms prior to CT. Physicians also estimated the likelihood of appendicitis. Test characteristics were calculated using clinical follow up as the reference standard. ROC curves were drawn. Results Of the 287 patients (mean age [range], 31 [12–88] years; 60% women), the prevalence of appendicitis was 33%. The Alvarado score had a positive likelihood ratio [LR(+)] (95% confidence interval) of 2.2 (1.7–3) and a negative likelihood ratio [LR(−)] of 0.6 (0.4–0.7). The modified Alvarado score (MAS) had LR(+) 2.4 (1.6–3.4) and LR(−) 0.7 (0.6–0.8). The RIPASA score had LR(+) 1.3 (1.1–1.5) and LR(−) 0.5 (0.4–0.8). Physician-determined likelihood of appendicitis had LR(+) 1.3 (1.2–1.5) and LR(−) 0.3 (0.2–0.6). When combined with physician likelihoods, LR(+) and LR(−) was 3.67 and 0.48 (Alvarado), 2.33 and 0.45 (RIPASA), and 3.87 and 0.47 (MAS). The AUC was highest for physician-determined likelihood (0.72), but was not statistically significantly different from the clinical scores (RIPASA – 0.67, Alvarado 0.72, MAS 0.7). Conclusions Clinical scoring systems performed equally well as physician gestalt in predicting appendicitis. These scores do not obviate the need for imaging for possible appendicitis when a physician deems it necessary.

Purpose To compare the accuracy of magnetic resonance (MR) imaging with that of computed tomography (CT) for the diagnosis of acute appendicitis in emergency department (ED) patients. Materials and Methods This was an institutional review board-approved, prospective, observational study of ED patients at an academic medical center (February 2012 to August 2014). Eligible patients were nonpregnant and 12- year-old or older patients in whom a CT study had been ordered for evaluation for appendicitis. After informed consent was obtained, CT and MR imaging (with non-contrast material-enhanced, diffusion-weighted, and intravenous contrast-enhanced sequences) were performed in tandem, and the images were subsequently retrospectively interpreted in random order by three abdominal radiologists who were blinded to the patients' clinical outcomes. Likelihood of appendicitis was rated on a five-point scale for both CT and MR imaging. A composite reference standard of surgical and histopathologic results and clinical follow-up was used, arbitrated by an expert panel of three investigators. Test characteristics were calculated and reported as point estimates with 95% confidence intervals (CIs). Results Analysis included images of 198 patients (114 women [58%]; mean age, 31.6 years ± 14.2 [range, 12-81 years]; prevalence of appendicitis, 32.3%). The sensitivity and specificity were 96.9% (95% CI: 88.2%, 99.5%) and 81.3% (95% CI: 73.5%, 87.3%) for MR imaging and 98.4% (95% CI: 90.5%, 99.9%) and 89.6% (95% CI: 82.8%, 94.0%) for CT, respectively, when a cutoff point of 3 or higher was used. The positive and negative likelihood ratios were 5.2 (95% CI: 3.7, 7.7) and 0.04 (95% CI: 0, 0.11) for MR imaging and 9.4 (95% CI: 5.9, 16.4) and 0.02 (95% CI: 0.00, 0.06) for CT, respectively. Receiver operating characteristic curve analysis demonstrated that the optimal cutoff point to maximize accuracy was 4 or higher, at which point there was no difference between MR imaging and CT. Conclusion The diagnostic accuracy of MR imaging was similar to that of CT for the diagnosis of acute appendicitis.

OBJECTIVE Appendicitis is frequently diagnosed in the emergency department, most commonly using CT. The purpose of this study was to compare the diagnostic accuracy of contrast-enhanced MRI with that of contrast-enhanced CT for the diagnosis of appendicitis in adolescents when interpreted by abdominal radiologists and pediatric radiologists. SUBJECTS AND METHODS Our study included a prospectively enrolled cohort of 48 patients (12–20 years old) with nontraumatic abdominal pain who underwent CT and MRI. Fellowship-trained abdominal and pediatric radiologists reviewed all CT and MRI studies in randomized order, blinded to patient outcome. Likelihood for appendicitis was rated on a 5-point scale (1, definitely not appendicitis; 5, definitely appendicitis) for CT, the unenhanced portion of the MRI, and the entire contrast-enhanced MRI study. ROC curves were generated and AUC compared for each scan type for all six readers and then stratified by radiologist type. Image test characteristics, interrater reliability, and reading times were compared. RESULTS Sensitivity and specificity were 85.9% (95% CI, 76.2–92.7%) and 93.8% (95% CI, 89.7–96.7%) for unenhanced MRI, 93.6% (95% CI, 85.6–97.9%) and 94.3% (95% CI, 90.2–97%) for contrast-enhanced MRI, and 93.6% (95% CI, 85.6–97.9%) and 94.3% (95% CI, 90.2–97%) for CT. No difference was found in the diagnostic accuracy or interpretation time when comparing abdominal radiologists to pediatric radiologists (CT, 3.0 min vs 2.8 min; contrast-enhanced MRI, 2.4 min vs 1.8 min; unenhanced MRI, 1.5 min vs 2.3 min). Substantial agreement between abdominal and pediatric radiologists was seen for all methods (κ = 0.72–0.83). CONCLUSION The diagnostic accuracy of MRI to diagnose appendicitis was very similar to CT. No statistically significant difference in accuracy was observed between imaging modality or radiologist subspecialty.

Within the inherent limitations of a retrospective case-controlled analysis, we observed that the rate of MAPE was lower (more favorable) for patients following pulmonary MRA for the primary evaluation of suspected PE than following CTA.

Purpose To assess the ability of d-dimer testing to obviate the need for cross-sectional imaging for patients at “non-high risk” for pulmonary embolism (PE). Methods This is a retrospective study of emergency department patients at an academic medical center who underwent cross-sectional imaging (MRA or CTA) to evaluate for PE from 2008 to 2013. The primary outcome was the NPV of d-dimer testing when used in conjunction with clinical decision instruments (CDIs = Wells’, Revised Geneva, and Simplified Revised Geneva Scores). The reference standard for PE status included image test results and a six-month chart review follow-up for venous thromboembolism as a proxy for false negative imaging. Secondary analyses included ROC curves for each CDI and calculation of PE prevalence in each risk stratum. Results Of 459 patients, 41 (8.9%) had PE. None of the 76 patients (16.6%) with negative d-dimer results had PE. Thus, d-dimer testing had 100% sensitivity and NPV, and there were no differences in CDI performance. Similarly, when evaluated independently of d-dimer results, no CDI outperformed the others (areas under the ROC curves ranged 0.53–0.55). There was a significantly higher PE prevalence in the high versus “non-high risk” groups when stratified by the Wells’ Score (p = 0.03). Conclusions Negative d-dimer testing excluded PE in our retrospective cohort. Each CDI had similar NPVs, whether analyzed in conjunction with or independently of d-dimer results. Our results confirm that PE can be safely excluded in patients with “non-high risk” CDI scores and a negative d-dimer.