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Updated: May 24, 2026
In Vivo Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography
Published on: February 16, 2016
Transient ischemic dilation for coronary artery disease in quantitative analysis of same-day sestamibi myocardial
Yuan Xu1, Reza Arsanjani, Morgan Clond
1Department of Imaging, Cedars-Sinai Medical Center, 8700 Beverly Blvd, Taper #A238, Los Angeles, CA 90048, USA. yuan.xu@cshs.org
Insights
Transient ischemic dilation (TID) ratios from myocardial perfusion SPECT (MPS) effectively identify severe coronary artery disease (CAD). These TID ratios are valuable diagnostic markers for Mibi-Mibi protocols, improving detection of significant coronary artery blockages.
Area of Science:
- Cardiovascular Imaging
- Nuclear Cardiology
- Diagnostic Biomarkers
Background:
- Transient ischemic dilation (TID) of the left ventricle in myocardial perfusion SPECT (MPS) is a recognized indicator of severe coronary artery disease (CAD).
- The diagnostic utility of TID has not been previously assessed for 99mTc-sestamibi rest/stress protocols (Mibi-Mibi).
Purpose of the Study:
- To establish normal limits for TID ratios in Mibi-Mibi scans.
- To evaluate the diagnostic performance of TID ratios for identifying severe CAD using Mibi-Mibi protocols.
Main Methods:
- TID ratios were calculated from static and gated Mibi-Mibi MPS in 547 patients.
- Patients were categorized based on coronary angiography findings (severe, mild-to-moderate CAD) and Duke prognostic CAD index (DI).
- Coronary artery disease severity was defined by percentage of stenosis in major coronary arteries and number of affected vessels.
Main Results:
- Upper normal limits for TID and gated TID (TID(ed)) were established as 1.19 and 1.23, respectively, in low-likelihood patients.
- Abnormal TID incidence significantly increased with CAD severity, from 2% in normal patients to over 36% in severe CAD.
- Adding TID to perfusion deficit analysis improved sensitivity for detecting severe CAD (71% vs. 64% with TID alone, P < .05).
Conclusions:
- TID ratios derived from both gated and ungated Mibi-Mibi MPS are effective diagnostic markers for severe CAD.
- These findings support the integration of TID analysis into Mibi-Mibi protocols for enhanced CAD assessment.
Background:
Transient ischemic dilation (TID) of the left ventricle in myocardial perfusion SPECT (MPS) has been shown to be a clinically useful marker of severe coronary artery disease (CAD). However, TID has not been evaluated for 99mTc-sestamibi rest/stress protocols (Mibi-Mibi). We aimed to develop normal limits and evaluate diagnostic power of TID ratio for Mibi-Mibi scans.
Methods:
TID ratios were automatically derived from static rest/stress MPS (TID) and gated rest/stress MPS from the end-diastolic phase (TID(ed)) in 547 patients who underwent Mibi-Mibi scans [215 patients with correlating coronary angiography and 332 patients with low likelihood (LLk) of CAD]. Scans were classified as severe (≥ 70% stenosis in proximal left anterior descending (pLAD) artery or left main (LM), or ≥ 90% in ≥ 2 vessels), mild to moderate (≥ 90% stenosis in 1 vessel or ≥ 70%-90% in ≥ 1 vessel except pLAD or LM), and normal (<70% stenosis or LLk group). Another classification based on the angiographic Duke prognostic CAD index (DI) was also applied: DI ≥ 50, 30 ≤ DI < 50 and DI < 30 or LLk group.
Results:
The upper normal limits were 1.19 for TID and 1.23 for TID(ed) as established in 259 LLk patients. Both ratios increased with disease severity (P < .0001). Incidence of abnormal TID increased from 2% in normal patients to >36% in patients with severe CAD. Similarly, when DI was used to classify disease severity, the average ratios showed significant increasing trend with DI increase (P < .003); incidence of abnormal TID also increased with increasing DI. The incidence of abnormal TID in the group with high perfusion scores significantly increased compared to the group with low perfusion scores (stress total perfusion deficit, TPD < 3%) (P < .0001). The sensitivity for detecting severe CAD improved for TID when added to mild to moderate perfusion abnormality (3% ≤ TPD < 10%): 71% vs 64%, P < .05; and trended to improve for TID(ed)/TID(es): 69% vs 64%, P = .08, while the accuracy remained consistent if abnormal TID was considered as a marker in addition to stress TPD. Similar results were obtained when DI was used for the definition of severe CAD (sensitivity: 76% vs 66%, P < .05 when TID was combined with stress TPD).
Conclusion:
TID ratios obtained from gated or ungated Mibi-Mibi MPS and are useful markers of severe CAD.
