“SENSITIVITY OF ULTRASONOGRAPHY IN THE EARLY DIAGNOSIS OF CHOLELITHIASIS AMONG PATIENTS AGED 20–40 YEARS: A CROSS-SECTIONAL STUDY IN DERA ISMAIL KHAN, PAKISTAN” (2026) Pakistan Journal of Medical & Cardiological Review, 5(2), pp. 5899–5920. doi:10.66021/pakmcr1433.