A 42-year-old woman presents to the emergency department with upper abdominal pain and nausea. The patient reports a 2-day history of intermittent epigastric and right upper quadrant pain that began after eating a large, fatty meal. The pain radiates to her back and is accompanied by nausea and one episode of vomiting. She denies fever, chills, jaundice, or changes in stool or urine color. She has experienced similar but milder episodes in the past, which resolved on their own. Past Medical History: •Obesity (BMI: 32 kg/m²). •Recently started a very low-calorie diet for weight loss. Medications: •Multivitamins. Family History: •Mother with gallstones and cholecystectomy at age 50. Social History: •Non-smoker, occasional alcohol use. Physical Examination: •Vital signs: BP 130/80 mmHg, HR 92 bpm, Temp 98.6°F, RR 16/min. •Abdomen: Tenderness in the right upper quadrant with a positive Murphy’s sign. No rebound tenderness or guarding. Laboratory Results: •Liver function tests: Normal (ALT 24 U/L, AST 22 U/L, ALP 90 U/L, total bilirubin 0.8 mg/dL). •Amylase and lipase: Normal. •White blood cell count: Normal. What is the most appropriate imaging finding to confirm the diagnosis of biliary sludge in this patient?
