After a pain attack in the right subcostal area, a 38-year-old woman with overnutrition developed icteric skin and sclera, light colored feces, and dark urine. Her abdomen is distended and painful on palpation in the right subcostal area. Palpation detects liver enlargement by 2-3 cm. Blood test: total bilirubin – 90 mcmol/l, conjugated bilirubin 60 mcmol/L, What method of examination will be the most informative for diagnosis clarification?