A randomized, double-blind, crossover comparison of novel continuous bed motion versus traditional bed-position based whole body PET/CT

Objectives Continuous bed motion has recently been introduced for whole body PET/CT, representing a paradigm shift towards individualized and flexible acquisition planning. Increased patient comfort due to lack of abrupt position changes could be another, albeit still unproven advantage. For robust clinical implementation, image quality and quantitative accuracy should at least be equal to the prior standard of bed-position based step-and-shoot imaging.

Methods 68 patients referred for whole-body PET/CT of various malignancies serially underwent stop-and-go as well as continuous bed motion acquisition (Flow Motion™, Siemens) within the same session, in a randomized, crossover design. Patients and two independent observers were blinded to the sequence of scan techniques. Patient comfort/satisfaction was examined by a standardized questionnaire. SUVs were compared in reference sites (liver, muscle, two tumor lesions). Image quality, edge artifacts and CT misalignment were evaluated on a scale of 1-4.

Results Patients preferred Flow Motion™ (52 % vs. 22 % for stop-and-go; 26% abstention). It was considered to be less abrupt in motion (65 % vs. 8%), more silent (34 % vs. 8 %) and more relaxing (38% vs. 8 %). Image quality, SUV and CT misalignment did not differ between the two techniques. Regardless of the technique, the second examination had significantly higher SUVmax values ​​of the tumor lesions (P = 0.0002), and more CT misalignment (P = 0.0017). Flow Motion™ resulted in less edge artifacts (P<0.0001).

Conclusions Oncologic PET/CT with continuous table movement enhances patient comfort, with at least comparable image quality to traditional bed-by-bed acquisition. This novel technique will facilitate the implementation of innovative, flexible acquisition protocols.