Clinical Utility of Enhanced Relative Activity Recovery on Systolic Myocardial Perfusion SPECT: Lessons from PET.
SPECT and PET myocardial perfusion images show greater myocardial intensity and homogeneity in systole than diastole because of greater systolic myocardial thickness, less partial volume loss, and enhanced activity recovery. Consequently, conventional myocardial perfusion images obtained from whole cardiac cycles have lower myocardial intensity and greater heterogeneity than systolic images. Considering relative activity distribution on SPECT systolic images may add clinical utility to whole-cycle images and wall motion.


METHODS
Patients undergoing coronary angiogram within 4 mo after SPECT myocardial perfusion imaging were reviewed. Images were interpreted by 2 masked interpreters using a 17-segment, 5-point scale to determine summed rest scores (SSS), summed stress scores, and summed difference scores on conventional and systolic images in 603 patients (55.6% no coronary artery disease [no-CAD] and 44.4% CAD). Studies were considered normal when the SSS was less than 4 and summed difference score was less than 2.


RESULTS
In the no-CAD group, systolic SSS was lower than SSS from conventional images (2 ± 2.3 vs. 3 ± 2.6, P < 0.001). In contrast, SSS derived from systolic and conventional images were not different in the obstructive CAD group (9.1 ± 7.6 vs. 9.2 ± 7.4, P = 0.559). When systolic images were considered, true-negative studies increased from 27.2% to 43.3% (P < 0.001) whereas false-positive studies decreased from 28.4% to 12.3% (P < 0.001). True-positive (38% vs. 37.2%, P = 0.505) and false-negative studies (6.5% vs. 7%, P = 0.450) were not significantly changed. Diagnostic accuracy increased from 65.2% to 80.8% (P < 0.001).


CONCLUSIONS
For gated SPECT myocardial perfusion imaging, when relative activity distribution on systolic images was considered, false-positive studies were reduced and diagnostic accuracy was improved.
Division of Cardiovascular Medicine, Department of Internal Medicine, University of Texas Health and Science Center at Houston, Houston, Texas.
Danai
D
Kitkungvan
Division of Cardiovascular Medicine, Department of Internal Medicine, University of Texas Health and Science Center at Houston, Houston, Texas.
Pimprapa
P
Vejpongsa
Division of Cardiovascular Medicine, Department of Internal Medicine, University of Texas Health and Science Center at Houston, Houston, Texas.
Ketan P
KP
Korrane
Division of Cardiovascular Medicine, Department of Internal Medicine, University of Texas Health and Science Center at Houston, Houston, Texas.
Stefano
S
Sdringola
Division of Cardiovascular Medicine, Department of Internal Medicine, University of Texas Health and Science Center at Houston, Houston, Texas K.Lance.Gould@uth.tmc.edu.
K Lance
KL
Gould
D000368:Aged; D017023:Coronary Angiography; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D015637:Gated Blood-Pool Imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D055414:Myocardial Perfusion Imaging / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D013599:Systole; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*
D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi
ECG gated SPECT perfusion images; SPECT image artifact; myocardial perfusion imaging; systolic myocardial perfusion SPECT