RSNA 2003 

Abstract Archives of the RSNA, 2003


499-p

Analysis of Detectability of CT Documented Lung Nodules on Chest Radiographs

Scientific Posters

Presented on December 3, 2003
Presented as part of L03: Chest Lung Nodules

Participants

Zhimin Huo PhD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: To assess the detectability and significance of lung nodules on chest radiographs Methods and Materials: We collected 80 consecutive computed radiographic (CR) chest images with a CT documented lung nodule. We randomly selected 11 of these cases and 9 additional normal chest images to form a set of 20 images for a real-time study at RSNA 2002. The size of the 11 nodules ranged from 7x7 mm to 36x23 mm. At RSNA 2002, these 20 images were presented on a high-resolution monochrome monitor to 26 observers. They were asked to mark the locations of each lung nodule seen as well as their confidence (a 100-point confidence scale) about whether or not the nodule was actually present. Subsequently, they were asked to retrospectively review images on which they had missed nodules in their initial readings with the CT-determined nodule locations now marked on the image. They were allowed to manipulate the contrast and brightness of each image to maximize the visibility of the nodule, asked to rate the visibility of the nodule on a 5-point scale (1: invisible; 5: highly visible), and were also asked if their visibility warranted further evaluation with CT. Results: Among 26 participants, there were 6 chest and 12 general radiologists. Analysis of their data yielded Az values of 0.8±0.07, and 0.7±0.16 from ROC analysis and sensitivities of 52% and 31%. In the 66 reads of cases with nodules by the 6 chest radiologists, there were 32 missed detections (48%). Upon retrospective review of these images with the CT-determined nodule location now marked, 69% were thought to be of sufficient visibility to have warranted further evaluation. In the 132 reads by the 12 general radiologists, there were 91 missed detections (69%), which on retrospective review were recommended for further evaluation in 76%. Overall, 7 of the 11 cases were missed by at least half of the radiologists on the initial reading. A large-scale observer study using the 80 CR images is underway. Conclusion: Preliminary results showed that radiologists would recommend a CT exam for more than half of CT documented nodules that they had missed in their initial reading upon re-review of CR images with the nodule locations marked. Potential benefit of using a computer-aided diagnosis system to indicate possible nodule locations is suggested.       Questions about this event email: zhimin.huo@kodak.com

Cite This Abstract

Huo PhD, Z, Analysis of Detectability of CT Documented Lung Nodules on Chest Radiographs.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3102169.html