A 28-year-old pregnant woman presents with acute right lower quadrant pain, nausea, and vomiting. On examination, she has localized tenderness and guarding. What is the most appropriate initial imaging modality to evaluate for acute appendicitis?

Explanation

Transabdominal ultrasound (USG) is the most appropriate initial imaging modality for suspected acute appendicitis in pregnant patients. It is non-ionizing, readily available, and can effectively visualize the appendix and rule out other causes of right lower quadrant pain. If USG is inconclusive, MRI without contrast is the next preferred modality due to its excellent soft tissue resolution and lack of ionizing radiation. CT scan is generally avoided in pregnancy due to the risk of ionizing radiation to the fetus, unless the benefits clearly outweigh the risks and other modalities are inconclusive. Plain abdominal X-ray has very limited utility in diagnosing appendicitis.