A 28-year-old sexually active woman presents to the emergency department with sharp right upper quadrant (RUQ) pain that started three days ago. The pain is pleuritic, worsening with deep breaths and movement. She denies jaundice, nausea, or vomiting but reports fever, chills, lower abdominal discomfort, abnormal vaginal discharge, and dyspareunia (pain during intercourse) over the past two weeks. On examination: RUQ tenderness without rebound or guarding Mild lower abdominal tenderness Pelvic exam: Cervical motion tenderness (Chandelier sign) and purulent cervical discharge Her RUQ pain, cervical motion tenderness, and abnormal vaginal discharge strongly suggest Fitz-Hugh-Curtis Syndrome, a complication of pelvic inflammatory disease (PID) leading to perihepatitis. Which of the following diagnostic findings is most indicative of Fitz-Hugh-Curtis Syndrome?