SPECT gated blood pool phase analysis of lateral wall motion for prediction of CRT response.Amplitude, defined as the magnitude of contraction of the myocardium, is obtained from phase analysis but has not been investigated to the same extent as phase-based parameters for predicting the outcome of cardiac resynchronization therapy (CRT).  49 patients underwent a single photon emission computed tomography (SPECT) radionuclide angiography (RNA) scan as well as FDG viability and Rubidium-82 perfusion PET scans prior to undergoing CRT.  Phase analysis was performed on the SPECT RNA data to extract amplitude values used to define amplitude size (AmpSize) and amplitude score (AmpScore) parameters.  The largest ROC AUC values were obtained in the ischemic population where values of 0.67 and 0.68 were observed for lateral wall AmpSize and AmpScore respectively.  Lateral wall amplitude-based parameters obtained from SPECT RNA phase analysis produced an overall accuracy in predicting CRT response in ischemic patients that was not significantly different to that of PET lateral wall scar parameters. 
SPECT
49 patients underwent a single photon emission computed tomography (SPECT) radionuclide angiography (RNA) scan as well as FDG viability and Rubidium-82 perfusion PET scans prior to undergoing CRT.  Scar size and scar score were obtained from the PET scans based on a 5 segment model.  Lateral wall amplitude-based parameters obtained from SPECT RNA phase analysis produced an overall accuracy in predicting CRT response in ischemic patients that was not significantly different to that of PET lateral wall scar parameters. 
PET
49 patients underwent a single photon emission computed tomography (SPECT) radionuclide angiography (RNA) scan as well as FDG viability and Rubidium-82 perfusion PET scans prior to undergoing CRT.  Phase analysis was performed on the SPECT RNA data to extract amplitude values used to define amplitude size (AmpSize) and amplitude score (AmpScore) parameters.  Lateral wall amplitude-based parameters obtained from SPECT RNA phase analysis produced an overall accuracy in predicting CRT response in ischemic patients that was not significantly different to that of PET lateral wall scar parameters. 
RNA
The largest ROC AUC values were obtained in the ischemic population where values of 0.67 and 0.68 were observed for lateral wall AmpSize and AmpScore respectively. 
ROC AUC
Scar parameters were then compared to amplitude parameters in the lateral wall for the whole population as well as both ischemic (N = 27) and non-ischemic (N = 22) populations using Pearson correlation. 
Pearson correlation