Diagnostic Accuracy of Multidetector CT for Detecting Ampullary Carcinoma: A Cross-Sectional Study

Abstract

Background Ampullary carcinoma is an uncommon gastrointestinal malignancy in which timely diagnosis is essential for curative treatment. Although multidetector three-dimensional computed tomography (3D CT) is routinely used for evaluating periampullary lesions, evidence regarding its diagnostic accuracy in South Asian populations remains limited. This study evaluated the diagnostic performance of multidetector 3D CT for detecting ampullary carcinoma using histopathology as the reference standard. Methods A cross-sectional diagnostic accuracy study was conducted at the Department of Radiology, Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan. A total of 186 consecutive patients with suspected ampullary carcinoma underwent contrast-enhanced multidetector 3D CT followed by histopathological confirmation through endoscopic biopsy or surgical resection. Diagnostic performance was assessed by calculating sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), overall diagnostic accuracy, likelihood ratios, diagnostic odds ratio, receiver operating characteristic (ROC) curve, and Cohen's κ agreement. Results Histopathology confirmed ampullary carcinoma in 43 (23.1%) patients. Multidetector 3D CT demonstrated a sensitivity of 90.7% (95% CI: 77.9–97.4%), specificity of 91.6% (95% CI: 85.8–95.5%), PPV of 76.5% , NPV of 97.0% , and overall diagnostic accuracy of 91.4% (95% CI: 86.4–94.9%). The positive and negative likelihood ratios were 10.8 and 0.10 , respectively, while the diagnostic odds ratio was 106.4 . ROC analysis demonstrated excellent discriminative ability with an AUC of 0.911 (95% CI: 0.864–0.958; p <0.001). Agreement between CT and histopathology was substantial (Cohen's κ = 0.79 , p <0.001).