Transient Ischemic Dilation of the Left Ventricle on SPECT: Correlation with Findings at Coronary CT Angiography.
Transient ischemic dilation (TID) in the setting of abnormal stress-rest cardiac SPECT myocardial perfusion imaging (MPI) has been linked with increased cardiovascular risk. However, the significance of TID in the setting of an otherwise normal SPECT MPI study has not been clearly established. In this study, cardiac CT was used to evaluate the prevalence of atherosclerotic lesions and the severity of coronary artery stenosis in patients with TID of the left ventricle with or without associated myocardial perfusion defects on SPECT MPI.


METHODS
The study population consisted of 1,553 consecutive patients who had undergone both cardiac CT and SPECT MPI within 1 mo between January 1, 2006, and September 1, 2011. Patients included in the study group had a pathologic TID value defined as ≥1.18 for men and ≥1.22 for women. Coronary CT angiography was used to evaluate each coronary segment for the presence and composition of atherosclerotic plaque and the degree of coronary stenosis. TID-positive patients were compared with a 2:1 risk-factor-matched-pair control cohort without TID.


RESULTS
TID was identified in 30 patients who were compared with TID-negative risk-factor-matched controls (n = 60). When compared with the TID-negative control cohort, TID-positive patients had no significant differences in the presence and extent of atherosclerosis, the degree of coronary artery stenosis, or the calcium score at cardiac CT. Similarly, there were no significant differences in these CT measures in TID-positive patients with a normal perfusion study (n = 20) when compared with TID-negative patients with a normal perfusion study (n = 48). In addition, there was no significant difference in the incidence of major adverse cardiac events when comparing both the TID-positive patients and the TID-negative control cohort and when comparing patients who were TID-positive with normal perfusion with patients who were TID-negative with normal perfusion.


CONCLUSIONS
The presence of TID with an otherwise normal SPECT MPI study does not translate into a greater extent of coronary artery disease as assessed by cardiac CT or increased risk for future major adverse cardiac events.
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina.
William T
WT
Halligan
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina.
Pamela B
PB
Morris
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina schoepf@musc.edu.
U Joseph
UJ
Schoepf
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina.
Blaine T
BT
Mischen
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina.
James V
JV
Spearman
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina.
J Reid
JR
Spears
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina.
Philipp
P
Blanke
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina Department of Radiology, Konyang University College of Medicine, Daejeon, Korea; and.
Young Jun
YJ
Cho
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina.
Justin R
JR
Silverman
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina.
Salvatore A
SA
Chiaramida
Heart and Vascular Center, Medical University of South Carolina, Charleston, South Carolina Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich, Germany.
Ullrich
U
Ebersberger
D016022:Case-Control Studies; D017023:Coronary Angiography; D005260:Female; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
SPECT; coronary artery disease; coronary computed tomography angiography; myocardial perfusion imaging; transient ischemic dilation