Do we really need additional contrast-enhanced abdominal computed tomography for differential diagnosis in triage of middle-aged subjects with suspected biliary pain

A meta-analysis of the performance of ultrasound, hepatobiliary scintigraphy, CT and MRI in the diagnosis of acute cholecystitis

PURPOSE

To evaluate the recently reported relative diagnostic accuracy of US, CT, MRI, and cholescintigraphy for diagnosing acute cholecystitis.

METHODS

2 radiologists independently performed systematic electronic searches for articles published between 2000 and 2021 and applied inclusion/exclusion criteria. 2 different radiologists extracted data from the articles and scored each with a methodological quality tool. Pooled estimates of sensitivity and specificity were calculated with a bivariate linear mixed model. A second analysis made head-to-head comparisons (US vs. CT, US vs. cholescintigraphy). Factors were also analyzed for potential confounding effects on diagnostic accuracy.

RESULTS

Of 6121 initial titles, 22 were included. The prevalence of cholecystitis varied widely across studies (9.4-98%). Pooled sensitivity and specificity estimates were 69% (confidence limit [CL] 62-76%) and 79% (CL 71-86%) for US, 91% (CL 86-94%) and 63% (CL 51-74%) for cholescintigraphy, 78% (CL 69-84%) and 81% (CL 71-88%) for CT, and 91% (CL 78-97%) and 93% (CL 70-99%) for MRI. Regarding head-to-head comparisons, the sensitivity of CT (87.6%, CL 70-96%) was significantly higher than US (66.8%, CL 43-84%), while specificities (81.7% with CL 54-95% for US, 91.9% with CL 67-99% for CT) were similar. The sensitivity of cholescintigraphy (87.4%, CL 76-94%) was significantly greater than US (61.6%, CL 44-77%), while the specificity of US (82%, CL 65-92%) was significantly higher than cholescintigraphy (68%, CL 47-84%).

CONCLUSION

Recent data suggests that CT may have a higher sensitivity than US for diagnosing acute cholecystitis, with similar specificity. Cholescintigraphy remains a highly sensitive modality with lower specificity than previously reported. MRI remains under studied, but with promising results.

The Role of Noncontrast CT in the Evaluation of Surgical Abdomen Patients

Acute surgical abdomen is commonly encountered in the ED and CT is widely used as an informative diagnostic tool to evaluate potential surgical indications. However, the adverse effects of contrast material used in CTscanning have been documented. We sought to delineate the role of noncontrast CT in the evaluation of patients with acute surgical abdomen. Between August 2015 and December 2015, patients with nontraumatic surgical abdomen who underwent preoperative CT were enrolled in the current study. The patients for whom the CT results permitted surgical decision-making were the focus of this study. The disease entities included acute appendicitis, acute cholecystitis, hollow organ perforation, mechanical bowel obstruction, intra-abdominal abscess that could not be drained percutaneously, and ischemic bowel disease. The results of contrast-enhanced and noncontrast CT were compared and analyzed. The surgical conditions identifiable by noncontrast CT were recorded. In total, 227 patients were enrolled in the study. In 90.7 per cent of patients overall, the findings indicating the need for surgical treatment were visualized on both the noncontrast and contrast-enhanced images (acute appendicitis: 89.3%, acute cholecystitis: 89.7%, hollow organ perforation: 97.4%, bowel obstruction: 100%, intra-abdominal abscess: 100%, and ischemic bowel disease: 55.6%). Noncontrast CT provides benefit for critical decision-making. Body mass index may affect the accuracy of noncontrast imaging in the evaluation of patients with surgical abdomen. In some specific situations, contrast enhancement remains necessary.

Diagnostic accuracy of non-contrast abdominal CT scans performed as follow-up for patients with an established cancer diagnosis: a retrospective study

OBJECTIVES

To determine the accuracy and non-detection rate of cancer related findings (CRFs) on follow-up non-contrast-enhanced CT (NECT) versus contrast-enhanced CT (CECT) images of the abdomen in patients with a known cancer diagnosis.

METHODS

A retrospective review of 352 consecutive CTs of the abdomen performed with and without IV contrast between March 2010 and October 2014 for follow-up of cancer was included. Two radiologists independently assessed the NECT portions of the studies. The reader was provided the primary cancer diagnosis and access to the most recent prior NECT study. The accuracy and non-detection rates were determined by comparing our results to the archived reports as a gold standard.

RESULTS

A total of 383 CRFs were found in the archived reports of the 352 abdominal CTs. The average non-detection rate for the NECTs compared to the CECTs was 3.0% (11.5/383) with an accuracy of 97.0% (371.5/383) in identifying CRFs. The most common findings missed were vascular thrombosis with a non-detection rate of 100%. The accuracy for non-vascular CRFs was 99.1%.

CONCLUSION

Follow-up NECT abdomen studies are highly accurate in the detection of CRFs in patients with an established cancer diagnosis, except in cases where vascular involvement is suspected.