The solitary pulmonary nodule is a common finding on CXR and the widespread use of CT has further increased the detection of this type of initial goal of the clinician is to distinguish the benign from the malignant lesion • Because SPNs are first detected on chest x-ray films, ascertaining whether the nodule is in the lung or outside it is important. A chest x-ray film taken from a lateral (side) position, fluoroscopy, or CT scan may help confirm the location of the nodule. • Although nodules of 5 mm diameter are occasionally found on chest x-ray films, SPNs are. | The solitary pulmonary nodule The solitary pulmonary nodule is a common finding on CXR and the widespread use of CT has further increased the detection of this type of initial goal of the clinician is to distinguish the benign from the malignant lesion Because SPNs are first detected on chest x-ray films ascertaining whether the nodule is in the lung or outside it is important. A chest x-ray film taken from a lateral side position fluoroscopy or CT scan may help confirm the location of the nodule. Although nodules of 5 mm diameter are occasionally found on chest x-ray films SPNs are often 8-10 mm in diameter. The most important step is determining the possibility and risk of the SPN being malignant. Patients who have an older chest x-ray film should show it to their health care provider for comparison. This is important because the growth rate of a nodule can be ascertained. The doubling time of most malignant SPNs is 1-6 months and any nodule that grows more slowly or more rapidly is likely to be benign. Chest x-rays films can provide information regarding size shape cavitation growth rate and calcification pattern. All of these features can help determine whether the lesion is benign or malignant. However none of these features is entirely specific for lung cancer. Radiologic characteristics that may help establish the diagnosis with reasonable certainty include 1 a benign pattern of calcification 2 a growth rate that is either too slow or too fast to be lung cancer 3 a specific shape or appearance of the nodule consistent with that of a benign lesion and 4 unequivocal evidence of another benign disease process. CT scan CT scan is an invaluable aid in identifying features of the nodule and determining the likelihood of cancer. In addition to the features seen on a chest x-ray film CT scan of the chest allows better assessment of the nodule. The advantages of CT scan over chest x-ray film include the following o Better resolution Nodules as small as 3-4
