Which of the following findings can help differentiate between benign and malignant pleural disease on CT?

1. Mediastinal pleural involvement*
2. Avid enhancement
3. Presence of calcifications
4. Associated lung abnormality

• Mediastinal pleural involvement can help differentiate between benign and malignant pleural disease on CT.
• The remaining options have not been described as helping to differentiate between malignant and benign pleural disease.

Which of the following is the best criteria for identification of peritoneal metastasis in patients with ovarian cancer?

1. Presence of ascites
2. Parietal peritoneal thickening
3. Small bowel wall thickening
4. Nodular soft tissue lesion on the peritoneal surface*

• A nodular soft tissue lesion is the most specific criteria for identifying peritoneal metastasis in patients with ovarian cancer. Note that CT performs similarly to MRI in identifying peritoneal disease, and both modalities perform well for implants greater than5 mm in size.
• The remaining options are not specific for peritoneal disease. Ascites and peritoneal thickening can be seen with peritoneal spread but can also be unrelated to malignancy (e.g. reactive).Small bowel wall thickening can be from a variety of causes.

Which of the following is a blind spot where melanoma metastases can be missed on CT?

1. Adrenal glands
2. Pancreas
3. Subcutaneous fat*
4. Lungs

• The subcutaneous tissue is a known blind spot and a location where melanoma can often metastasize.
• The remaining options are not known blind spots, although melanoma can metastasize to any of these organs.

Which of the following findings are strongly suggestive of malignancy in a breast lesions identified on CT?

1. Calcification
2. Spiculation*
3. Avid enhancement
4. Intralesional fat

• Spiculation of a breast lesion has high specificity for breast cancer.
• Calcification and avid enhancement can be seen with breast cancer, but do not have the same specificity as spiculation.
• Intralesional fat is not suggestive of malignancy in a breast lesion.

Blind spots are areas where lesions are most commonly overlooked. Which of the following is considered a blind spot in abdominal CT imaging?

1. Liver capsule
2. Lung bases
3. Paraspinal region*
4. Ovaries

• The paraspinal region is a known blindspot in abdominal CT imaging, along with the subcutaneous tissue, peritoneal surface, and prostate gland. The remaining options have not been described or characterized as blind spots.