Diagnostic Performance of Focused Assessment with Sonography for Trauma (FAST) versus Contrast-Enhanced Computed Tomography in Blunt Abdominal Trauma: A Cross-Sectional Observational Study

Background: Blunt abdominal trauma (BAT) is a major cause of morbidity and mortality, particularly among young adults. Focused Assessment with Sonography for Trauma (FAST) is a rapid bedside screening tool, while contrast-enhanced computed tomography (CECT) remains the reference standard. Comparative data from Indian tertiary centres on the diagnostic performance of FAST versus CECT in haemodynamically stable patients remain limited. Material and Methods: This cross-sectional observational study enrolled 210 consecutive haemodynamically stable adults (18-60 years) with BAT who underwent both FAST and CECT abdomen at a tertiary care teaching hospital in Central India. FAST findings (presence/absence of free fluid) were compared with CECT as the reference standard. Diagnostic accuracy indices (sensitivity, specificity, PPV, NPV), kappa agreement, and chi-square association were calculated. Demographic, clinical, and injury characteristics were also analysed. Results: Mean age was 33.09 ± 11.07 years; 77.1% were male. Road traffic accidents accounted for 65.7% of injuries. FAST was positive in 128 patients (61.0%) and CECT in 150 patients (71.4%). Using CECT as reference, FAST demonstrated sensitivity 80.0%, specificity 86.7%, PPV 93.8%, and NPV 63.4%. Moderate agreement was observed (κ=0.601). The association between FAST and CECT findings was statistically significant (p<0.001). Solid organ injury was present in 71.4% (liver most common, 34.3%); hollow viscus injury occurred in 17.1%. Conclusion: FAST is a useful, rapid screening modality with high specificity and PPV in haemodynamically stable BAT patients. Its moderate sensitivity and lower NPV indicate that a negative FAST does not reliably exclude significant intra-abdominal injury. CECT remains essential for definitive evaluation, especially when clinical suspicion persists.

Keywords: Blunt abdominal trauma, FAST, CECT, Diagnostic accuracy, Hemoperitoneum, Solid organ injury, Trauma imaging, Emergency surgery.