American Board of Internal Medicine (ABIM) Certification Practice Exam

Which imaging studies are included in the preoperative staging workup for colon cancer?

1. Ultrasound of the abdomen and pelvis

2. Contrast-enhanced CT scans of the chest, abdomen, and pelvis

3. MRI of the pelvis

4. Plain X-rays of the abdomen

The correct answer is: Contrast-enhanced CT scans of the chest, abdomen, and pelvis

In the preoperative staging workup for colon cancer, contrast-enhanced CT scans of the chest, abdomen, and pelvis are essential. This imaging modality is highly effective in evaluating the extent of the disease, including detecting any metastatic lesions in the liver, lungs, and peritoneal cavity. Contrast-enhanced CT scans provide detailed cross-sectional images of the internal anatomy, allowing for accurate assessment of the primary tumor, lymph node involvement, and the presence of distant metastases. This comprehensive approach helps in determining the stage of the colon cancer, guiding surgical treatment decisions, and identifying any additional interventions that may be necessary. The use of contrast also enhances the visibility of blood vessels and tissue structures, making it easier to differentiate between benign and malignant processes. Other imaging studies, such as ultrasound of the abdomen and pelvis, MRI of the pelvis, and plain X-rays of the abdomen, have limited roles in the staging of colon cancer. While they may be used in specific situations, such as for assessing particular symptoms or findings, they do not provide the same level of detail or information that a contrast-enhanced CT scan offers in the context of colon cancer staging. Hence, the choice of a contrast-enhanced CT scan is pivotal in forming an accurate staging picture necessary for