Solitary pulmonary nodule: A diagnostic algorithm in the light of current imaging technique

Abstract

The solitary pulmonary nodule (SPN) is frequently seen on chest radiographs and computed tomography (CT). The finding of a SPN usually provokes a flurry of clinical and imaging activity as an SPN in at-risk population is an alert signal of possible lung cancer. The frequency of malignant nodules in a given population is variable and depends on the endemicity of granulomatous disease. The percentage of malignant nodules also rises when dealing with at-risk population. The problem is compounded by the fact that with the present generation of CT scanners, 1–2 mm nodules are discovered in approximately half of the smokers aged 50 years or older scanned. A variety of management approaches are applied in the work-up of SPN often requiring evaluation over a long period of time to establish a benign or malignant diagnosis. Comparison with previous imaging studies and morphologic evaluation of the size, margins, and internal characteristics are usually the first step in the evaluation of these nodules. It is often necessary to use additional imaging techniques and occasionally invasive procedures such a percutaneous needle lung or a surgical biopsy. Until recently, the guidelines for follow-up of indeterminate noncalcified nodules detected on nonscreening CT was a minimum of 2 years. However, during the past few years due to further refinements in CT technology and better understanding of tumor behavior, it has prompted a revision of the guidelines of the follow-up of small indeterminate nodules. These guidelines have been endorsed by the Fleischner Society.

Radiologic Features of Small Pulmonary Nodules and Lung Cancer Risk in the National Lung Screening Trial: A Nested Case-Control Study

“…At present there are no published data assessing vessel-attached nodules for lung cancer risk; however, vessel-attached nodules may be more vascular and angiogenic which is a key factor in cancer growth by supplying a nodule with required nutrients and extent of vascularity differs between benign and malignant pulmonary nodules (27). Our finding for nodule location is consistent with the natural history of lung cancer as primary malignant nodules are commonly located in upper lobes (28, 29). Our analysis revealed that 69.8% of the case patients had small pulmonary nodules in the upper lobes at the baseline screen compared to 43.9% in the control subjects.…”

A CT-based radiomics nomogram for prediction of lung adenocarcinomas and granulomatous lesions in patient with solitary sub-centimeter solid nodules

“…Radiologists typically risk stratify non-calcified pulmonary nodules by interpreting nodule characteristics such as location, attenuation, diameter, volume, and margins [ 38 , 39 ]. Our findings showed that SCSN location is consistent with the natural history of lung cancer, as primary malignant nodules are commonly located in the upper lobes [ 40 ]. However, granulomatous lesions also common in the upper lobes, especially in the background of the high tuberculosis incidence in Asia area.…”

Non-Contrast-Enhanced Whole-Body Magnetic Resonance Imaging in the General Population: The Incidence of Abnormal Findings in Patients 50 Years Old and Younger Compared to Older Subjects

“…Based on imaging findings, the prevalence of a wide range of incidental findings such as silent brain infarcts, intervertebral disc degeneration, lung nodules, liver hemangiomas, adrenal adenomas, renal cell carcinomas and uterine fibroids, appeared to be more frequent than previously thought [18]–[24], [39]–[41].…”