The aim of this pilot study is to evaluate the clinical utility of a novel 3D user interface approach that provides 6 degrees of freedom(6 DOF) input with the help of a motion sensitive game controller for evaluation of pulmonary embolism at computed tomography angiography(CTA).Evaluation
Retrospective analysis of 36 patients (13M,23F;mean age 53+/-13 yrs) referred for CTA to rule out PE over one year. 11 of 36 patients had PE. The 6DOF tool was used to create on-the-fly oblique reformations and compared to conventional Radiology PACS with multiplanar reformatted images (MPR) and advanced visualization workstation with real-time MPR manipulation capabilities (Vitrea, Vital Images, Minneapolis, MN). Time to diagnosis and diagnostic confidence were recorded separately for each interface by a single observer starting with the 6 DOF tool. A second observer used the 6 DOF tool on two occasions 3 weeks apart. The final radiologic report was considered the gold standard. Time to diagnosis was compared using a Wilcoxon rank sum test comparing the 6 DOF tool, PACS, and 3D post-processing software(Vitrea). A two-tailed t-test was used to compare times recorded by the second observer.Discussion
The 6 DOF tool enabled review of all datasets and detection of all PE. There was a temporal advantage of the 3D tool (41.7+/-15.6 s) over standard PACS (83.9+/-30.7 sec,p<0.05) and 3D post-processing software (66.6+/-17.7 s, p<0.05). There was a significant reduction in time to diagnosis by the second reviewer upon second attempt(46.26+/-27.1 s, improving to 36.47+/-18.8 s, p<0.05). Diagnostic confidence was similar among the different viewing interfaces.Conclusion
The novel 6DOF technology has the ability to save time in CT diagnosis of PE without compromising diagnostic confidence. Time to diagnosis is further improved with repeated use of the tool. Applications of the new 3D user interface tool are not limited to CT angiography and include any volumetric cross-sectional data sets. This may be useful in reducing the burden of reformats on PACS and improve clinical throughput. Potential applications include teaching anatomy, procedural planning, and interrogation of large time-resolved volumetric data.