Differences between computed tomoghaphy and surgical findings in acute complicated diverticulitis

ACR Appropriateness Criteria® Left Lower Quadrant Pain: 2023 Update

The differential diagnosis for left lower quadrant pain is wide and conditions range from the benign and self-limited to life-threatening surgical emergencies. Along with patient history, physical examination, and laboratory tests, imaging is often critical to limit the differential diagnosis and identify life-threatening abnormalities. This document will discuss the guidelines for the appropriate use of imaging in the initial workup for patients who present with left lower quadrant pain, patients with suspected diverticulitis, and patients with suspected complications from diverticulitis. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Accuracy of preoperative CT staging of acute colonic diverticulitis using the classification of diverticular disease (CDD) - Is there a beneficial impact of water enema and visceral obesity?

PURPOSE

We evaluated the accuracy of preoperative CT in staging colonic diverticulitis (ACD) by using the classification of diverticular disease (CDD) and investigated the diagnostic impact of water enema (WE) and visceral obesity.

METHODS

In this retrospective study, the radiological and hospital information system was searched for patients who underwent CT for clinically suspected ACD prior to surgery between 2009 and 2019. From the initial population (n = 164), we included 155 patients (94.5 %) (85 women; mean age: 58 ± 13 years) matching the following inclusion criteria: i.) clinically suspected ACD, ii.) i.v. contrast-enhanced CT, iii.) surgery for ACD within 1 week after CT, iv.) histopathological report that proved ACD. The remaining 9 patients (5.5 %) were excluded because histopathological reports were lacking (n = 3) or CT was performed without intravenous contrast agent (n = 6). WE (+ butylscopolamine i.v.) was performed in 93 patients (group A, 60 %). 62 patients (group B, 40 %) had no WE. Visceral-to-subcutaneous fat ratio (V/S) was determined for each patient. Two radiologists blinded for final diagnosis independently staged ACD according to CDD and assessed prevalence and confidence ratings of ACD-related CT-findings: pericolonic fat stranding, covered- and free-perforation, local and generalized peritonitis, abscess. Interobserver-agreement of CT-findings were assessed and effects of WE and V/S ratio on the diagnostic accuracy of CT with surgical and histopathological findings as reference were determined by calculating a logistic regression model.

RESULTS

CT-staging showed high accuracy (94 %) and excellent interrater-correlation (ICC 0.96) for staging ACD. WE had no positive impact neither on diagnostic accuracy of staging, nor on confidence ratings of ACD-related CT-findings (all p > 0.5). Confidence ratings were significantly higher in examinations without WE for perforation, peritonitis as well as abscesses (all p < 0.5). Confidence ratings for the assessment of local peritonitis improved significantly with higher V/S (p = 0.049). The increase of V/S significantly correlated with the probability for correct CDD staging of ACD in CT (p = 0.023).

CONCLUSION

Increase of visceral obesity significantly improves accuracy of CT in preoperative staging acute colonic diverticulitis. However, independently of the degree of visceral obesity, water enema has no diagnostic benefit and may therefore be omitted. Overall, CT proves high accuracy in preoperative staging ACD using the classification of diverticular disease.

LEVEL OF EVIDENCE

Retrospective study, observational study.

Is Lung Ultrasound Imaging a Worthwhile Procedure for Severe Acute Respiratory Syndrome Coronavirus 2 Pneumonia Detection?

OBJECTIVES

We compared 2 imaging modalities in patients suspected of having coronavirus disease 2019 (COVID-19) pneumonia. Blinded to the results of real-time reverse transcriptase polymerase chain reaction (rRT-PCR) testing, lung ultrasound (LUS) examinations and chest computed tomography (CT) were performed, and the specific characteristics of these imaging studies were assessed.

METHODS

From March 15, 2020, to April 15, 2020, 63 consecutive patients were enrolled in this prospective pilot study. All patients underwent hematochemical tests, LUS examinations, chest CT, and confirmatory rRT-PCR. The diagnostic performance of LUS and chest CT was calculated with rRT-PCR as a reference. The interobserver agreement of radiologists and ultrasound examiners was calculated. Ultrasound and CT features were compared to assess the sensitivity, specificity, positive predictive value, and negative predictive value. Positive and negative likelihood ratios measured the diagnostic accuracy.

RESULTS

Nineteen (30%) patients were COVID-19 negative, and 44 (70%) were positive. No differences in demographics and clinical data at presentation were observed among positive and negative patients. Interobserver agreement for CT had a κ value of 0.877, whereas for LUS, it was 0.714. The sensitivity, specificity, positive predictive value, and negative predictive value of chest CT for COVID-19 pneumonia were 93%, 90%, 85%, and 95%, respectively; whereas for LUS, they were 68%, 79%, 88%, and 52%. On receiver operating characteristic curves, area under the curve values were 0.834 (95% confidence interval, 0.711-0.958) and 0.745 (95% confidence interval, 0.606-0.884) for chest CT and LUS.

CONCLUSIONS

Lung ultrasound had good reliability compared to chest CT. Therefore, our results indicate that LUS may be used to assess patients suspected of having COVID-19 pneumonia.

To Fill or Not to Fill? - Value of the Administration of Positive Rectal Contrast for CT Evaluation of Diverticular Disease of the Colon

PURPOSE

 To assess the value of the administration of positive rectal contrast at CT in patients referred for suspected diverticular disease (DD) of the colon.

MATERIALS AND METHODS

 460 patients (253 male, 207 female; median age 62 years; interquartile range 24) with clinical suspicion of DD of the colon were included in this retrospective IRB-approved study. CT was performed with i. v. contrast only (n = 328, group M1), i. v. + positive rectal contrast (n = 82, group M2), neither i. v. nor rectal contrast (n = 32, group S1), or positive rectal contrast only (n = 19, group S2). Two readers in consensus evaluated all CT datasets concerning diagnosis of DD (yes/no) and categorized findings (classification of diverticular disease (CDD)). Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values for the diagnosis of DD were calculated for all groups, using either clinical follow-up (n = 335) or intraoperative findings (n = 125) as the reference standard. In patients undergoing surgery, radiological staging of DD was correlated with the histopathology (weighted Cohen-k).

RESULTS

 224 patients (48.7 %) were diagnosed with DD. The sensitivity, specificity, PPV, and NPV were as follows. Group M1 / M2: 92 %/92 %, 97 %/94 %, 96 %/96 %, 94 %/89 %, respectively; group S1 / S2: 94 %/86 %, 93 %/80 %, 94 %/92 %, 93 %/67 %, respectively. Radiological staging and histopathology correlated substantially in all groups (k = 0.748-0.861).

CONCLUSION

 Abdominal CT had a high sensitivity and specificity for the diagnosis of DD. Disease staging correlated well with the findings at surgery. Additional positive rectal contrast administration did not have a significant advantage and may therefore be omitted in patients with suspected DD.

KEY POINTS

· CT has a high sensitivity and specificity for diagnosis of DD.. · CT staging using the CDD algorithm correlates very well with surgery.. · Positive rectal contrast administration does not improve diagnosis and radiological staging..

CITATION FORMAT

· Meyer S, Schmidbauer M, Wacker FK et al. To Fill or Not to Fill? - Value of the Administration of Positive Rectal Contrast for CT Evaluation of Diverticular Disease of the Colon. Fortschr Röntgenstr 2021; 193: 804 - 812.