Solitary pulmonary nodule (SPN) is defined as a rounded opacity≤3 cm in diameter surrounded by lung parenchyma. The majority of smokers who undergo thin-section CT have SPNs, most of which are smaller than 7 mm. In the past, multiple follow-up examinations over a two-year period, including CT follow-up at 3, 6, 12, 18, and 24 months, were recommended when such nodules are detected incidentally. This policy increases radiation burden for the affected population. Nodule features such as shape, edge characteristics, cavitation, and location have not yet been found to be accurate for distinguishing benign from malignant nodules. When SPN is considered to be indeterminate in the initial exam, the risk factor of the patients should be evaluated, which includes patients' age and smoking history. The 2005 Fleischner Society guideline stated that at least 99% of all nodules 4 mm or smaller are benign; when nodule is 5-9 mm in diameter, the best strategy is surveillance. The timing of these control examinations varies according to the nodule size (4-6, or 6-8 mm) and the type of patients, specifically at low or high risk of malignancy concerned. Noncalcified nodules larger than 8 mm diameter bear a substantial risk of malignancy, additional options such as contrast material-enhanced CT, positron emission tomography (PET), percutaneous needle biopsy, and thoracoscopic resection or videoassisted thoracoscopic resection should be considered.
Objective To analyze the clinical presentations and radiological characteristics of pathologically proved cases of cryptogenic organizing pneumonia(COP).Methods The clinical and radiological features of 8 patients with COP confirmed by open lung biopsy were analyzed.Treatment and follow-up data were also recorded.Results There were 5 male an 3 female patients aged 37 to 68 years.Dyspnea，cough and inspiratory crackles were the most common symptoms and signs.Various computed tomography findings including ground glass opacities,pathy consolidation with air bronchograms，nodules and reticulation were simultaneously observed in the same patient.The diagnostic imaging features of COP were patchy or lobar consolidation，often by a predominantly subpleural distribution，and irregular band-like opacities distributed along the bronchovascular bundle or located in the subpleural area.All patients were treated with corticosteroids and yielded significant improvement in seven cases.Conclusions COP could be diagnosed by clinical and radiological findings and histopathological examination was needed for confirmed diagnosis.In general，COP responds well to glucocorticoid therapy and has a benign prognosis.
