Multidetector CT of the solitary pulmonary nodule

Evaluation and management of pulmonary nodules: state-of-the-art and future perspectives

INTRODUCTION

The imaging evaluation of pulmonary nodules, often incidentally detected on imaging examinations performed for other clinical reasons, is a frequently encountered clinical circumstance. With advances in imaging modalities, both the detection and characterization of pulmonary nodules continue to evolve and improve.

AREAS COVERED

This article will review the imaging modalities used to detect and diagnose benign and malignant pulmonary nodules, with a focus on computed tomography (CT), which continues to be the mainstay for evaluation. The authors discuss recent advances in the lung nodule management, and an algorithm for the management of indeterminate pulmonary nodules.

EXPERT OPINION

There are set of criteria that define a benign nodule, the most important of which are the lack of temporal change for 2 years or more, and certain benign imaging criteria, including specific patterns of calcification or the presence of fat. Although some indeterminate pulmonary nodules are immediately actionable, generally those approaching 1 cm or larger in diameter, at which size the diagnostic accuracy of tools such as positron emission tomography (PET)/CT, single photon emission CT (SPECT) and biopsy techniques are sufficient to warrant their use. The majority of indeterminate pulmonary nodules are under 1 cm, for which serial CT examinations through at least 2 years for solid nodules and 3 years for ground-glass nodules, are used to demonstrate either benign biologic behavior or otherwise. The management of incidental pulmonary nodules involves a multidisciplinary approach in which radiology plays a pivotal role. Newer imaging and postprocessing techniques have made this a more accurate technique eliminating ambiguity and unnecessary follow-up.

Lung nodule computer-aided detection as a second reader: influence on radiology residents

OBJECTIVE

The purpose of this study was to evaluate the use of a computed tomographic lung nodule computer-aided detection (CAD) software as a second reader for radiology residents.

METHODS

The study involved 110 cases from 4 sites. Three expert radiologists identified nodules that were 4 to 30 mm in maximum diameter to form the ground truth. These cases were then interpreted by 6 board-certified radiologists and 6 radiology residents. The residents read each case without and then with a CAD software (Lung Nodule Assesment, Extended Brilliance Workspace; Philips Healthcare, Highlands Heights, OH) to identify nodules that were 4 to 30 mm in maximum diameter.

RESULTS

The experts identified 91 nodules as the ground truth for the study. The mean sensitivity of the 6 board-certified radiologists was 89%. The mean sensitivity of the residents was 85% without the CAD and 90% (P < 0.05) with the CAD as a second reader.

CONCLUSIONS

The CAD software can help improve the sensitivity of residents in the detection of pulmonary nodules on computed tomography, making them comparable with board-certified radiologists.