Which imaging modality is considered first-line for the evaluation of acute appendicitis?

Abdominal ultrasound is considered the first-line imaging modality for the evaluation of acute appendicitis, particularly in certain populations such as children and pregnant patients. This preference is primarily due to ultrasound's lack of ionizing radiation, making it a safer choice for these vulnerable groups. In addition, ultrasound can effectively visualize the appendix and identify signs of inflammation, such as increased diameter and surrounding fluid, which are indicative of appendicitis.

Ultrasound is particularly valuable in pediatric cases because children have a higher risk for radiation exposure-related complications. Additionally, in pregnant patients, ultrasound can help in assessing abdominal pain while minimizing risks to the developing fetus.

While CT imaging with contrast is highly sensitive and specific for diagnosing appendicitis in adults, it involves radiation exposure, making it less ideal as the first-line imaging technique in populations where minimizing such exposure is a concern. X-ray and plain abdominal films are rarely utilized in the modern evaluation of suspected appendicitis, as they have low sensitivity for this condition and do not provide sufficient detail regarding the appendix or surrounding structures.