Mesothelioma Diagnosis Diagnostic Imaging 2 — Questions and Answers
Question 1: On CT imaging, which feature is most suggestive of peritoneal mesothelioma?
- Diffuse peritoneal thickening with ascites (Correct answer)
- Single large abdominal mass
- Isolated hepatic lesion
- Retroperitoneal lymphadenopathy alone
Correct answer: Diffuse peritoneal thickening with ascites
Peritoneal mesothelioma typically appears on CT as diffuse peritoneal thickening or nodularity accompanied by ascites.
Question 2: Which imaging finding on CT is used to calculate the peritoneal cancer index (PCI) in peritoneal mesothelioma?
- Distribution and size of peritoneal tumor deposits (Correct answer)
- Diameter of the largest lymph node
- Volume of ascites
- Thickness of the bowel wall
Correct answer: Distribution and size of peritoneal tumor deposits
The PCI is calculated by scoring the size and distribution of tumor deposits across 13 abdominal regions on CT to guide surgical planning.
Question 3: What is the advantage of using integrated PET/CT over CT alone in staging mesothelioma?
- Better detection of occult nodal and distant metastatic disease (Correct answer)
- Higher spatial resolution for pleural detail
- Lower radiation dose
- Better assessment of fluid density
Correct answer: Better detection of occult nodal and distant metastatic disease
PET/CT combines functional metabolic data with anatomical detail, improving detection of nodal metastases and distant spread that CT alone may miss.
Question 4: Which MRI sequence is most useful for characterizing the relationship of pleural mesothelioma to the diaphragm?
- T2-weighted imaging (Correct answer)
- T1-weighted post-contrast
- Diffusion-weighted imaging
- STIR sequence
Correct answer: T2-weighted imaging
T2-weighted MRI provides excellent contrast between tumor and adjacent structures, helping delineate diaphragmatic involvement.
Question 5: In mesothelioma imaging, contralateral pleural disease or pericardial extension indicates which TNM stage?
- Stage IV (Correct answer)
- Stage I
- Stage II
- Stage III
Correct answer: Stage IV
Extension to contralateral pleura or pericardium indicates advanced T4 disease, placing the patient in Stage IV of the IMIG staging system.
Question 6: Ultrasound of the chest in mesothelioma is most useful for which clinical application?
- Guiding thoracentesis and pleural biopsy (Correct answer)
- Full tumor staging
- Mediastinal assessment
- Lymph node mapping
Correct answer: Guiding thoracentesis and pleural biopsy
Ultrasound is primarily used at the bedside to guide thoracentesis (fluid drainage) and image-guided pleural biopsy safely.
Mesothelioma Diagnosis Diagnostic Imaging 2
On CT imaging, which feature is most suggestive of peritoneal mesothelioma?