Correction of hysteretic respiratory motion in SPECT myocardial perfusion imaging: Simulation and patient studies

Abstract

Purpose Amplitude based respiratory gating is known to capture the extent of respiratory motion (RM) accurately but results in residual motion in the presence of respiratory hysteresis. In our previous study, we proposed and developed a novel approach to account for respiratory hysteresis by applying the Bouc-Wen (BW) model of hysteresis to external surrogate signals of anterior / posterior motion of the abdomen and chest with respiration. In this work using simulated and clinical SPECT myocardial perfusion imaging (MPI) studies, we investigate the effects of respiratory hysteresis and evaluate the benefit of correcting it using the proposed BW model in comparison with the abdomen signal typically employed clinically. Methods The MRI navigator data acquired in free breathing human volunteers were used in the specially modified 4-D NCAT phantoms to allow simulating three types of respiratory patterns: monotonic, mild-hysteresis, and strong-hysteresis with normal myocardial uptake, and perfusion defects in the anterior, lateral, inferior, and septal locations of the mid-ventricular wall. Clinical scans were performed using a 99mTc-Sestamibi MPI protocol while recording respiratory signals from thoracic and abdomen regions using a Visual Tracking System (VTS). The performance of the correction using the respiratory signals was assessed through polar map analysis in phantom and ten clinical studies selected on the basis of having substantial RM. Results In phantom studies, simulations illustrating normal myocardial uptake showed significant differences (p<0.001) in the uniformity of the polar maps between the RM uncorrected and corrected. No significant differences were seen in the polar map uniformity across the RM corrections. Studies simulating perfusion defects showed significantly decreased errors (p<0.001) in defect severity and extent for the RM corrected compared to the uncorrected. Only for the strong-hysteretic pattern was there a significant difference (p<0.001) among the RM corrections. The errors in defect severity and extent for the RM correction using abdomen signal were significantly higher compared to that of the BW (severity=-4.0%, p<0.001; extent=-65.4%, p<0.01) and chest (severity=-4.1%, p<0.001; extent=-52.5%, p<0.01) signals. In clinical studies, the quantitative analysis of the polar maps demonstrated qualitative and quantitative but not statistically significant differences (p=0.73) between the correction methods that used the BW signal and the abdominal signal. Conclusions This study shows that hysteresis in respiration affects the extent of residual motion left in the RM binned data, which can impact wall uniformity and the visualization of defects. Thus there appears to be the potential for improved accuracy in reconstruction in the presence of hysteretic RM with the BW model method providing a possible step in the direction of improvement.

Simplified Quantification and Acquisition Protocol for 123I-MIBG Dynamic SPECT

“…Respiratory and cardiac motion correction was not used in this study but, if implemented, might further improve the quantification accuracy of the V T image. Several innovative respiratory and cardiac motion correction methods have been proposed recently (24)(25)(26)(27)(28), and we will investigate adding a motion correction technique to our future study protocol.…”

A blind deconvolution method incorporated with anatomical‐based filtering for partial volume correction: Validations with 123I‐mIBG cardiac SPECT/CT

“…On the other hand, the cardiac, respiratory, or patient motion, which may result in a spatially variant PSF, has not been incorporated into our PVC method. However, various innovative motion correction methods have been proposed for PET/SPECT systems . Although the topic of motion correction is currently beyond the scope of this paper, we plan to incorporate motion correction prior to the proposed PVC process in the future to further improve the accuracy of SPECT quantification.…”

Cardiac and Respiratory Self-Gating in Radial MRI Using an Adapted Singular Spectrum Analysis (SSA-FARY)

“…For respiratory gating it is usually assumed that inspiration and expiration do not have to be distinguished [50,20,16]. However, various studies reveal that respiratory motion is heavily subject-dependent and exhibits a strong variability as well as hysteresis which affects the global position of the myocardium [51,52,53,54]. Hence, inspiration and expiration should be distinguished to properly resolve the effects of breathing motion on the heart.…”