Effect of morphing between unenhanced and multiscale enhanced chest radiographs on pulmonary nodule detection
Mariusz W. Pietrzyk, Fabian Zöhrer, Markus Harz, Mark F. McEntee, Horst Karl Hahn, Tamara Miner Haygood, Micheal G. Evanoff, Patrick Brennan · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2012
Aim: This study aims to determine the effectiveness of a novel image-processing algorithm for multi-scale enhancement of chest radiographs to improve detection and localization of real pulmonary nodules. Background: Our wavelet-based enhancement method interactively adjusts the contrast of medical images extracting the spatial frequency components at different scales, followed by a weighting procedure. This study aims to explore the usefulness of this novel procedure for chest image reporting. Method: Sixteen radiologists viewed 50 PA chest radiographs in order to localize pulmonary nodules. The databank contains 25 normal and 25 abnormal images, with multi-nodule cases. Subjects were allowed to mark unlimited number of locations followed by ranking confidence of nodule presence according to a 5-level scale. Subjects viewed all cases at least in two out of three conditions: unprocessed, enhanced and with morphing between these two. MCMR ROC and JAFROC analyses were conducted. Results: No significant differences were found in ROC AUC values across modalities and specialities. Only localization performance with morphing tool is significantly higher (F(1,8)=13.303, p=0.007) for chest expert (JAFROC FOM=0.6355) from non-chest (JAFROC FOM=0.4675) radiologists. Conclusion: Radiologists specialized in chest image interpretation performed consistently well in localizing pulmonary nodules, whereas non-chest radiologists were suffer from distracting effect of morphing tool.