A novel method for incorporating respiratory-matched attenuation correction in the motion correction of cardiac PET–CT studies

Abstract

Mismatches between PET and CT datasets due to respiratory effects can lead to artefactual perfusion defects. To overcome this, we have proposed a method of aligning a single CT with each frame of a gated PET study in a semi-automatic manner, incorporating a statistical shape model of the diaphragm and a rigid registration of the heart. This ensures that the structures that could influence the appearance of the reconstructed cardiac activity are correctly matched between emission and transmission datasets. When tested on two patient studies, it was found in both cases that attenuation correction using the proposed technique resulted in PET images that were closer to the gold standard of attenuation correction with a gated CT, compared with scenarios where only heart matching was considered (and not the diaphragm) or where no transformation was performed (i.e. where a single CT frame was used to attenuation-correct all PET frames). These preliminary results suggest that diaphragm matching between PET and CT improves the quantitative accuracy of reconstructed PET images and that the proposed method of using a statistical shape model to describe the diaphragm shape and motion, in combination with a rigid registration to determine respiratory-induced heart motion, is a feasible method of achieving this.

Respiratory motion models: A review

“…Motion models have been proposed to provide the motion estimates for MCIR (Ambwani et al, 2011;Fayad et al, 2010;Reyes et al, 2007) and RTA King et al, 2012), but to the authors' knowledge, no motion model based technique has been proposed using LOR correction. In addition, a number of motion model techniques have been proposed for use in PET imaging without being specific as to which motion correction approach they are intended for (McQuaid et al, 2009;McQuaid and Lambrou, 2011;Rahni et al, 2011).…”

MRI Investigation of the Linkage Between Respiratory Motion of the Heart and Markers on Patient’s Abdomen and Chest: Implications for Respiratory Amplitude Binning List-Mode PET and SPECT Studies

“…The most common regions investigated have been the lung [10]–[14], diaphragm [7], [15], and heart [9], [16], [17]. For example, Nehrke et al [9] reported on the presence of hysteresis between the displacements of the heart and the diaphragm during free breathing using a multi-navigator echo technique in MRI.…”

Interpolated Average CT for Attenuation Correction in PET—A Simulation Study

“…In order to reduce data redundancy, we just simulated the noise based on the clinical data for CACT, HCT-1, IACT 2o , and IACT 4o [see Figs. 4,9,10,and 12], as HCT-5 and HCT-8 should have the similar noise level as compared to HCT-1 and IACT 2s should have the similar noise level as compared to IACT 2o in the noisy CT simulations. The noisy simulation results for a motion of 3 cm were in accordance with those of the motion of 2 cm and were not shown here.…”

“…Nehmeh et al [9] spatially matched the 4-D CT data with the gated PET images according to the externally monitored breathing signal and showed improved lesion registration, with the cost of increasing CT radiation dose. McQuaid et al [10] proposed aligning a single CT with each gated frame of PET via a statistical shape model of the diaphragm and a rigid registration of the heart to improve quantitative accuracy. Similar investigation was also proposed by Wells et al [11].…”