Single-slice versus multi-slice display for human-observer lesion-detection studies

Use of a single-slice (2D) display for observer studies may bias results and reduce the study's clinical generalizability. Human observers perform better at the task of lesion detection with 3D-processed images than they do with 2D-processed images when the images are presented using a 2D display. However, 3D-processing techniques incorporate information from out-of-plane or adjacent slices into an image and thus provide more information to the observer than does a similar 2D-processing method. Observer performance with 2D-processing methods may improve if the adjacent-slice information is provided by way of a multi-slice (3D) display. 3D processing also introduces 3D distracters which may not be present with 2D processing. The authors investigated, with a human-observer LROC study, the impact of 2D versus 3D display on FBP and OSEM reconstruction followed by 2D and 3D filtering. Three display modes were used: single-slice, multi-slice, and multi-slice with cine. The emulated clinical task was the detection and localization of small gallium lesions in thoracic SPECT scans. Results indicate that 3D display generally improves performance over the 2D display, as measured by the area under the LROC curve and the probability of correct localization. The improvement is greater for 2D- than for 3D-filtered reconstruction leading to a reduction in the significance of the differences between them.