Evaluation of Solitary Pulmonary Nodule

A solitary pulmonary nodule(SPN), or “coin lesion,” is an approximately round lesion that is less than 3 cm in diameter and that is completely surrounded by pulmonary parenchyma,without other abnormalities. Chest X ray usually detects the lesion but,computed tomographic (CT) imaginghas improved physicians’ ability to assess each of these features and is now critical inthe evaluation of the lesions.Features of SPN specific for cancer are the "corona radiata sign"(or spiculated border) and scalloped border.Calcification within a nodule suggests that it isa benign lesion.A classic “popcorn”pattern is most often seen in hamartomas while "BULLS EYE" calcification is suggestive of a granuloma.Doubling time is the time taken by SPN to double it's volume or a 30 percent increase in diameter of the lesion.Bronchogenic tumours have a doubling time of 200-400 days. Beningn lesions have a doubling time of >400days,while aggresive metastses and inflammatory lesions have a doubling time of few days. Calcification patterns that are stippled or eccentric have been associated with cancer.The traditional standard of imaging at three-month intervals during the first yearafter a nodule is discovered and then at six-months intervals during the next year is logical, provided that high-resolution CT is used, rather than plain film radiography.Nonsurgical tests to help distinguish benign from malignant nodules include CT densitometry, contrast-enhanced CT, bronchoscopy, transthoracicfine-needle aspiration biopsy, and more recently,positron-emission tomography (PET).Transthoracicfine-needle aspiration biopsy for larger (≥1 cm) andmore suspicious lesions in high risk individuals and serial CT scanningat three-month intervals for smaller lesions were used, with good results.

Solitary Pulmonary Nodule