Computer-aided diagnoses: Automatic detection of lung nodules

• Published in: Medical physics (Lancaster) 1998-10, Vol.25 (10), p.1998-2006
• Main Authors: Carreira, Marı́a J., Cabello, Diego, Penedo, Manuel G., Mosquera, Antonio
• Format: Article
• Language: English
• Subjects: 87.56.01.a; Algorithms; Artificial Intelligence; Biophysical Phenomena; Biophysics; chest radiography; Computer Simulation; computer‐aided diagnoses; Diagnosis, Computer-Assisted - methods; Diagnosis, Computer-Assisted - statistics & numerical data; diagnostic radiography; False Positive Reactions; feature extraction; Humans; Image analysis; Image detection systems; Image processing; knowledge based systems; lung; Lung Neoplasms - diagnostic imaging; lung nodule detection; Lungs; Medical image contrast; medical image processing; Medical imaging; Numerical modeling; pattern recognition; Physicists; Radiographic Image Enhancement - methods; Radiography
• ISSN: 0094-2405; 2473-4209
• DOI: 10.1118/1.598388

This work describes a computational scheme for automatic detection of suspected lung nodules in a chest radiograph. A knowledge-based system extracts the lung masks over which we will apply the nodule detection process. First we obtain the normalized cross-correlation image. Next we detect suspicious regions by assuming a threshold. We examine the suspicious regions using a variable threshold which results in the growth of the suspicious areas and an increase in false positives. We reduce the large number of false positives by applying the facet model to the suspicious regions of the image. An algorithmic classification process gives a confidence factor that a suspicious region is a nodule. Five chest images containing 30 known nodules were used as a training set. We evaluated the system by analyzing 30 chest images with 40 confirmed nodules of varying contrast and size located in various parts of the lungs. The system detected 100% of the nodules with a mean of six false positives per image. The accuracy and specificity were 96%.