Objective: To evaluate the diagnostic performance of cystic artery colour Doppler ultrasound indices in differentiating acute from chronic cholecystitis and to assess their added value over clinical and grayscale findings.

Methods: In this prospective study, 101 adults with clinically suspected cholecystitis underwent ultrasound before cholecystectomy. Grayscale features and colour Doppler measurements of cystic and hepatic artery peak systolic velocity and resistive index were recorded; histopathology was the reference standard. Logistic regression models using clinical and grayscale variables alone and then with cystic artery peak systolic velocity were evaluated with receiver operating characteristic analysis.

Results: In total, 33 patients had acute and 68 had chronic cholecystitis. Acute cholecystitis showed more abnormal grayscale features, including increased gallbladder size, wall thickening and pericholecystic change. Cystic artery peak systolic velocity was higher in acute than chronic disease (40.8 ± 14.9 vs 26.1 ± 15.5 cm/s; p < 0.001), as was hepatic artery peak systolic velocity (74.0 ± 24.4 vs 60.2 ± 22.4 cm/s; p = 0.006), whereas resistive index did not differ meaningfully. Cystic artery peak systolic velocity showed fair discrimination (area under the curve 0.78; cut-off 31.5 cm/s; sensitivity 0.91; specificity 0.71); hepatic artery peak systolic velocity performed more modestly (area under the curve 0.67). Adding cystic artery peak systolic velocity to a grayscale-only model produced negligible improvement in overall performance.

Conclusion: Cystic artery peak systolic velocity is a useful adjunct for distinguishing acute from chronic cholecystitis when grayscale findings are equivocal, whereas resistive index adds little diagnostic value. Routine Doppler assessment is unlikely to change decisions when grayscale ultrasound is definitive.