Cause determination of missed lung nodules and impact of reader training and education: simulation study with nodule insertion software
Subba R Digumarthy1, Roberto Lo Gullo2, Marie-Helene Levesque3, Karl Sayegh4, Sishir Rao1, Scott B Raymond1, Alexi Otrakji1, Mannudeep K Kalra1
1 Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA
2 Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Boston, MA, USA; Department of Radiology, School of Medicine, University of Milano, Milan, Italy
3 Institut Universitaire de cardiologie et de Pneumologie de Quebec, Canada
4 Department of Radiology, McGill University, Montreal, Canada
Subba R Digumarthy,
Department of Radiology, Massachusetts General Hospital, 75 Blossom Court, Unit#230, Boston, MA 02114
Source of Support: None, Conflict of Interest: None
Background: There are “blind spots” on chest computed tomography (CT) where pulmonary nodules can easily be overlooked. The number of missed pulmonary nodules can be minimized by instituting a training program with particular focus on the depiction of nodules at blind spots.
Purpose: The purpose of this study was to assess the variation in lung nodule detection in chest CT based on location, attenuation characteristics, and reader experience.
Materials and Methods: We selected 18 noncalcified lung nodules (6–8 mm) suspicious of primary and metastatic lung cancer with solid (n = 7), pure ground-glass (6), and part-solid ground-glass (5) attenuation from 12 chest CT scans. These nodules were randomly inserted in chest CT of 34 patients in lung hila, 1st costochondral junction, branching vessels, paramediastinal lungs, lung apices, juxta-diaphragm, and middle and outer thirds of the lungs. Two residents and two chest imaging clinical fellows evaluated the CT images twice, over a 4-month interval. Before the second reading session, the readers were trained and made aware of the potential blind spots. Chi-square test was used to assess statistical significance.
Results: Pretraining session: Fellows detected significantly more part-solid ground-glass nodules compared to residents (P = 0.008). A substantial number of nodules adjacent to branching vessels and posterior mediastinum were missed. Posttraining session: There was a significant increase in detectability independent of attenuation and location of nodules for all readers (P < 0.0008).
Conclusion: Dedicated chest CT training improves detection of lung nodules, especially the part-solid ground-glass nodules. Detection of nodules adjacent to branching vessels and the posterior mediastinal lungs is difficult even for fellowship-trained radiologists.