Controversies in computed tomography of the thorax. The pulmonary nodule - lung cancer staging

The role of computed tomography (CT) in the evaluation of the solitary pulmonary nodule and in the staging of lung cancer has generated significant controversy over the past few years. The divergent opinions expressed by knowledgeable investigators have left the practicing radiologist in a state of semiconfusion as to the proper place of CT in these two important areas of thoracic radiology. Although the causes of medical controversies are numerous and varied, they can nonetheless be classified into a few general categories. First, the technique itself may not be uniform during the period when the technology is rapidly evolving. Second, patient populations may not be equivalent because of geographic differences or institutional selection of patients. Third, differences in methods may significantly affect results. For example, apparently similar pathologic end points may lead to significantly different results, as illustrated by the decrease in the apparent sensitivity of CT in lung staging when every lymph node is systematically resected as compared with selective resection of the nodes palpated as abnormal by the surgeon at thoracotomy. Fourth, prevailing biases in the clinical environment of the investigators may affect their conclusions. For instance, when a conservative approach to surgical therapy is favored, noninvasive diagnostic methods appear more valuable, as they are extensively relied upon for better selection of patients for surgery. Fifth, and most important, there is the ever-evolving nature of medical knowledge, characterized by a lack of basic understanding of many disease processes, leading to necessary conjectures, assumptions, and opinions that are not always convergent.