Fragmentary window filtering for multiscale lung nodule detection: Preliminary study

Rationale and Objectives. The authors evaluated computer-assisted diagnostic (CAD) methods used to detect suspicious areas on lung radiographs. Materials and Methods. The authors designed a fragmentary window filtering (FWF) algorithm for detecting lung nodule patterns, which generally appear as circular areas of high opacity on the chest radiograph. The FWF algorithm helps differentiate circular patterns from overlapping radiographic background. A multiscale analysis was performed to locate multiscale modules. Receiver operating characteristic analysis was performed by using a lung nodule that was extracted from a chest radiograph. The nodule underwent scalings and subsequent superimposition onto 140 normal regions of interest from six chest radiographs. Results. The FWF method was superior to the matched filtering method in the detection of suspicious areas. Conclusion. The proposed FWF-based method should provide improved detection of lung nodules on chest radiographs.