Dual "motion-frozen heart" combining respiration and contraction compensation in clinical myocardial perfusion SPECT imaging.
OBJECTIVE
This article assesses the effect of a new correction technique ("motion-frozen heart") which compensates for the previously described nonuniform blurring of myocardial perfusion imaging (MPI) due to respiration motion or cardiac contraction.


METHODS
Respiratory and ECG-gated one-day (99m)Tc-MIBI MPI studies performed in 48 patients were evaluated. MPI scans were acquired on a gamma camera supporting list-mode functionality synchronized with an external respiratory strap and an ECG device. Respiratory and cardiac-gated bins were generated using the acquired list file. Respiratory-gated bins were corrected for respiratory motion, followed by correction for cardiac contraction motion. In addition, cardiac contraction correction was applied to cardiac-gated bins uncorrected for respiratory motion. Bullseye maps were generated for uncorrected MPI studies, as well as following correction for respiratory motion, cardiac contraction, and both. The mean difference between each of the correction vs the uncorrected bullseye was calculated. Visual assessment of image quality, severity, and extent of the uncorrected perfusion images and following each of the corrections was performed.


RESULTS
Average motion due respiration was 7.0 +/- 2.6 mm in the axial plane. The maximal score difference in segmental uptake greater than 10% was found in 2%, 15%, and 25% following respiratory correction, contraction correction, and dual corrections, respectively. Percent of scans classified with an excellent image quality was 13%, 21%, 42%, and 52% for the uncorrected images and following respiratory correction, contraction correction, and dual corrections, respectively.


CONCLUSIONS
A technique that compensates for motion of the heart due to respiration and cardiac contraction in MPI-SPECT was evaluated. Compensating for both respiration and cardiac contraction had the greatest effect on perfusion images resulting in significantly improved image quality.
Kovalski
Gil
G
Faculty of Biomedical Engineering, Technion, Israel Institute of Technology, Haifa, 32000, Israel. bmgil@tx.technion.ac.il
Keidar
Zohar
Z
Frenkel
Alex
A
Sachs
Jonathan
J
Attia
Shai
S
Azhari
Haim
H
D016477:Artifacts; D055426:Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D055425:Respiratory-Gated Imaging Techniques / Q000379:methods*; D012680:Sensitivity and Specificity; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging*