role of CT in nodular lung lesions

ABSTRACT

One of the most frequent indications for thoracic CT is the detection and characterization of lung nodules. CT is more sensitive than plain chest radiography or whole lung tomography for detecting pulmonary nodules. CT will find up to 40% more nodules than will whole lung tomography, which will find 20% more nodules than plain chest radiography. The problem remains that most small uncalcified nodules are benign. Biopsy is needed to prove benignancy or malignancy unless unequivocal calcification is present. CT can aid in the search for calcification in some cases. Patients with malignancies having a high incidence of lung metastases should be considered for CT scans whether the plain chest radiography is normal or abnormal. This includes primary bone tumours, soft tissue sarcomas, renal cell carcinomas and melanomas. All patients with known tumours should receive CT regardless of plain chest radiographic findings. CT is used in many protocols to follow progression of tumour. Of practical notes, solitary pulmonary nodules seen on chest CT and appearing more than 1 year after the discovery of an extrathoracic neoplasm are more often a bronchogenic carcinoma than a metastatic lesion. CT adis in finding multiple nodules when they are present, as well as in obtaining biopsy proof of the disease process