Diagnostic Accuracy of Triphasic CT Scan in Differentiating Malignant from Benign Focal Liver Lesion by Taking Histopathology as Gold Standard in Cirrhotic Patients-A Systematic Review and Meta-Analysis

Background: Triphasic Computed Tomography (CT) has been used extensively as a non-invasive imaging technique for the assessment of focal liver lesions, especially in cirrhotic patients where the differentiation between benign and malignant lesions continues to be important. While extensively used in clinical practice, heterogeneity in study diagnostic performance resulted in a systematic evidence synthesis. Methods: A systematic review and meta-analysis were conducted following PRISMA. Cross-sectional and cohort studies that reported the diagnostic performance of triphasic CT using histopathology as the reference standard were included in the review. Extraction of data was for sensitivity, specificity, positive and negative predictive values and overall accuracy. Risk of bias was assessed using ROBINS-I and AXIS tools and GRADE was used to grade the certainty of evidence. A fixed-effects model was used in the meta-analysis and sensitivity analyses were conducted to assess the stability of the findings. Results: Eleven studies were analyzed. Pooled sensitivity and specificity of malignant lesions were 98.3% (95% CI: 95.9-100%) and 82.9% (95% CI: 71.4-94.4%), respectively. Positive and negative predictive values were 94.2% (95% CI: 90.1-98.4%) and 94.4% (95% CI: 86.9-100%), respectively. Diagnostic accuracy was 94.3% (95% CI: 90.6-97.9%) on average. Qualitative synthesis suggested that triphasic computed tomography was able to adequately depict typical imaging features of hepatocellular carcinoma like arterial phase hyperenhancement and delayed washout. Diagnostic difficulties were noted in lesions with atypical vascular patterns and in cirrhotic settings where benign regenerative nodules can be confused with malignancy. Conclusion: Triphasic CT was demonstrated to be excellent for differential diagnosis of benign versus malignant focal liver lesions in cirrhotic patients with extremely high sensitivity. Specificity, although mildly reduced, was probably due to background liver changes and atypical patterns of disease. The modality remains of clinical utility. Prospective multicentric validation should be performed to further define diagnostic criteria.