Assessment of respiratory tracking methods for motion correction in cardiac PET

Ziel/Aim Accurate evaluation of myocardial viability in chronic total occlusion (CTO) is crucial for the risk stratification of a revascularization procedure. In this sense, cardiac PET imaging has shown high sensitivity and specificity, but technical aspects as the heart motion during the respiratory cycle still jeopardize the quality of the images. Several methods have been proposed to detect heart motion; however, further comparative studies are needed in order to establish a reliable standard. In this work we quantitatively compared the performance of the three methods for respiratory motion tracking based on MR image Navigator (iNAV), PET data-driven and a belt device.

Methodik/Methods PET/MR viability assessment data from 11 CTO patients were used. Heart motion was tracked with three methods: apex tracking in iNAV, center of mass tracking in sinogram frames of 1 s (PDD1s) and 250 ms (PDD250ms); and diaphragm tracking with a belt. Then, gated PET reconstructions were performed using either respiratory motion corrected or uncorrected attenuation correction (AC) maps. Later, gated images were corrected for respiratory motion using a coronary MR angiography based RTA scheme, and quantitatively compared with the reference 10 min non-gated & uncorrected PET images, measuring the apparent myocardial wall thickness in the uptake profiles F-H & L-R.

Ergebnisse/Results Based on the analysis of 9 patients, we found statistically significant reductions of the myocardial thickness with iNAV (-5 %), PDD1s (-9 %), and PDD250ms (-11 %) when the motion amplitude was high (more than 3 gates). No significant difference was found with the belt. Moreover, the use of a corrected AC map did not improve the measurements.

Schlussfolgerungen/Conclusions Respiratory motion correction in cardiac PET images plays a relevant role only with high motion amplitude. MR- and PET- based methods for respiratory tracking leads to similar results, while the use the belt device did not show any advantage, raising concerns about its use in this procedure.

Publikationsverlauf

Artikel online veröffentlicht:
08. April 2021