Comparison of Ultrasound and CT Findings of Pelvic Masses with Histopathology: A Cross-sectional Study

Abstract

Introduction: Benign and malignant pelvic masses can occur in different age groups, primary diagnosis and choosing the appropriate surgical procedure is very important. Ultrasound (USG) is the diagnostic test of choice in evaluating pelvic masses, while Computed Tomography (CT) scan is most helpful as a second-line study, for in-depth evaluation of the abdomen and pelvis. Aim: To compare the findings of ultrasound and CT scans of pelvic masses with definitive histopathological or laboratory findings. Materials and Methods: A cross-sectional study was conducted at Government Medical College and Rajindra Hospital, Patiala, Punjab, India, from December 2014 to September 2015. Sixty patients from Outpatient and Inpatient Department, with clinical suspicion of pelvic pathology, were evaluated sonographically and then by CT scan. Ultrasound characterisation of mass as high or low risk was done based on septae and solid part echogenicity. CT findings used to diagnose malignancy were cystic solid mass, necrosis in a solid lesion, cystic lesion with thick, irregular walls or septa, and/or papillary projections. The presence of ascites, lymphadenopathy, omental cake, peritoneal deposits, mesenteric deposits was noted to diagnose metastasis. Data was analysed using Statistical Package for Social Sciences (SPSS) version 16.0. A p-value was calculated using Chi-square test. For finding, the level of agreement between USG/CT scan and histopathology, Kappa statistic was applied. Results: Ultrasound had sensitivity of 73.7%, specificity of 80.3%, Positive Predictive Value (PPV) of 53.8% and Negative Predictive Value (NPV) of 90.7%. Computed tomography scan had a sensitivity of 78%, specificity of 95.08%, PPV of 83.3%, and NPV of 93.5%. Kappa statistics showed moderate level of agreement between USG and histopathological findings (k=0.47, p-value=0.017) and good level of agreement between CT scan and histopathological findings (k=0.68, p-value=0.001). Conclusion: Ultrasound with its good sensitivity can be used as an effective screening modality for pelvic masses. Computed tomography scan has better specificity than USG and should be used as a confirmatory investigation.