What is the role of CT, MR and PET scans in the evaluation of Solitary pulmonary nodule?

• CT: is absolutely essential to better evaluate the lesion for size, margins, calcium and density measurements. It also enables us to determine whether it is single or are there multiple lesions not detected by CXR. Contrast enhancement appears to be an indicator of malignancy and vascularity. 20 HU is considered the threshold for positive test for enhancement.
• MR: Dynamic contrast enhanced MR measurements of tumor enhancement can provide similar information about the lesion. I dont see a particular need to do MR in solitary pulmonary nodule.
• PET: scan using 18f-flourodeoxyglucose is also useful in distinguishing malignant fronm benign lesions. It is not useful in lesions less than 2 cm in diameter.

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  My recommendation: MR and PET scanning for solitary pulmonary nodule is still in early stages of evaluation and we need to gain more experience to determine their role. At present CT scanning gives me all of the information I need for evaluation of solitary pulmonary nodule

  Ref:

  • Radiology.201(2):447-55,1996.
  • Radiology.203(3):681-6,1996.
  • AJR.168(3):771-4,1997.

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