Normal limits for transient ischemic dilation with 99mTc myocardial perfusion SPECT protocols

Slomka, Piotr J.; Berman, Daniel S.; Germano, Guido

doi:10.1007/s12350-016-0582-4

Cited by 8 publications

(6 citation statements)

References 16 publications

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“…Cut-off values in the literature for TIDr vary due to multiple factors and range between 1.16 and 1.31 as reported in a recent review. 4 Based on our cohort, we found that QPS-derived TIDr cut-off values for a 1-day protocol were similar at 1.28 and 1.31 for exercise and dipyridamole stress, respectively. The mean TIDr was not significantly different between the two groups, which may be due to statistical limitations arising from relatively small patient numbers in each group.…”

Section: Discussionmentioning

confidence: 63%

“…A common method for obtaining the TIDr threshold is to determine the mean TIDr in a cohort of ‘normal’ patients and then setting the cut-off value at the threshold of two SD above the mean. 4 An alternative method of using the 97.5th percentile has been proposed if the TIDr of the reference cohort does not follow a normal distribution. 20 …”

Section: Discussionmentioning

confidence: 99%

“…The cut-off value for significant TIDr differs depending on variables such as stress modality, gamma camera, imaging protocol, computation software, and even patient positioning. 4 Furthermore, previous studies have used various criteria to define the ‘normal’ reference population. These include a low (<5%) pre-test probability of CAD, 21 SSS of 3 and below, summed difference score of 1 and below, or an expert interpretation of a normal MPI scan.…”

Section: Discussionmentioning

confidence: 99%

“…The ‘normal’ TID ratio (TIDr) is known to differ between different stress agents and camera types. 4 Almost all previously published studies had derived the ‘normal’ TIDr thresholds using patients with normal myocardial perfusion and no prior history of CAD. 5 However, normal myocardial perfusion does not exclude underlying CAD completely as ‘balanced ischaemia’ can still occur.…”

Section: Introductionmentioning

confidence: 99%

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Transient ischaemic dilation ratio thresholds in patients with zero coronary calcium score undergoing exercise or dipyridamole stress SPECT myocardial perfusion imaging using a cadmium-zinc-telluride camera

Sim,

Yew

2023

European Heart Journal - Imaging Methods and Practice

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Aims Transient ischemic dilation (TID) is a marker of underlying extensive coronary artery disease (CAD) during myocardial perfusion imaging (MPI). The cut off for a normal TID ratio (TIDr) value is often derived from a cohort of individuals with no apparent CAD. Varying criteria have been used to define the absence of CAD. We aim to derive TIDr cut offs using patients with normal MPI and coronary artery calcium (CAC) score, of zero and compare TIDr obtained from different software packages. Methods and results We studied 232 patients with zero CAC and normal MPI undergoing exercise or dipyridamole stress using either a 1 or 2-day protocol. All patients were scanned in the supine position with a cadmium-zinc-telluride camera. TIDr was automatically generated using Quantitative Perfusion SPECT (QPS) software initially, and subsequently using Myometrix for comparison. The TIDr cut offs calculated using the mean + 2 standard deviation were 1.29 and 1.24 for the 1 and 2-day protocol groups respectively. Dipyridamole stress resulted in significantly higher mean TIDr in the 2-day protocol group (1.07 ± 0.13 vs 1.01 ± 0.12, p = 0.035). Myometrix derived TIDr were also significantly lower compared to QPS derived values for most protocols except 2-day exercise stress. Conclusion This study is the first to derive TIDr threshold values using a normal population defined by zero CAC and normal MPI. TIDr also varied depending on stress modality, protocol as well as software used.

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Section: Discussionmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Transient ischaemic dilation ratio thresholds in patients with zero coronary calcium score undergoing exercise or dipyridamole stress SPECT myocardial perfusion imaging using a cadmium-zinc-telluride camera

Sim,

Yew

2023

European Heart Journal - Imaging Methods and Practice

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“…Different cutoffs have been validated for different radioisotope and stress protocols (Table 1). 4 There are two possible interpretations related to VD in the gSPECT. The classic understanding is that there is extensive subendocardial ischemia generating stunning.…”

mentioning

confidence: 99%

Is left ventricular systolic index the new kid in the block?

Vita

Nestor²

2019

Journal of Nuclear Cardiology

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There are many diagnostic and prognostic elements arising from myocardial perfusion imaging studies. The equipment improvements have reduced acquisition time while enhancing quality imaging. In line with technological developments, a greater understanding of coronary pathophysiology, especially microcirculation, has allowed the clinical cardiologist to understand coronary artery disease (CAD). In the past, many cases had no physiopathology correlation with the clinical setting, for example, angina with normal coronary arteries. Nowadays, we have a more clear view of such findings.From the very beginning, ventricular dilatation (VD) during stress has proven to be associated with adverse outcomes, considering secondary to extensive ischemia.The prognostic value of VD has been associated with the presence of severe and extensive coronary disease since Chouraqui et al. 1 and Weiss et al. 2 publications 30 years ago.Exploring further, Mazzanti et al. 3 correlated the ischemia severity with VD using cinecoronariography as the gold standard. They showed a 71 and 95% of sensibility and specificity, respectively, by semiquantitative analysis.Ventricular dilatation without ischemia and normal myocardial perfusion imaging (MPI) have a less clear clinical and prognostic value. Gated SPECT (gSPECT) imaging relies on detection of endocardial edge for measurements of left ventricle (LV) volumes and transient ischemic dilatation (TID) ratio. The TID threshold depends on the radioisotope used, stress methods, proper algorithm, the avoidance of artifact motion, incorrect slice alignment, and the clinical setting of the population studied. Different cutoffs have been validated for different radioisotope and stress protocols (Table 1). 4 There are two possible interpretations related to VD in the gSPECT. The classic understanding is that there is extensive subendocardial ischemia generating stunning. The second interpretation, which is more frequently seen with pharmacological stress than exercise, is that adenosine induces subendocardial hypoperfusion. In patients with limited coronary flow reserve (CFR), adenosine produces vasodilatation in the vascular bed of both, the epicardial and endocardial vessels. As a consequence, there is an increasing flow from the subendocardium to the epicardium. This is different from ischemia in CAD. We called it ''vertical steal'' and it is a marker of impaired subendocardial CFR rather than a true myocardial stunning. The ''vertical steal'' explains the increasing frequency of TID in patients with diseases such as diabetes and hypertension and could go along with a change in left ventricular remodeling, more significant with adenosine than with exercise.Emmett et al. 5 studied TID on myocardial perfusion imaging with pharmacological stress. The author evaluated if TID was due to actual LV cavity dilation and ventricular stunning or to relative subendocardial hypoperfusion. He studied 31 patients undergoing

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Evaluation of Ventricular Function by Nuclear Imaging

Corrêa

Palazzo

2021

Nuclear Cardiology

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Normal limits for transient ischemic dilation with 99mTc myocardial perfusion SPECT protocols

Cited by 8 publications

References 16 publications

Transient ischaemic dilation ratio thresholds in patients with zero coronary calcium score undergoing exercise or dipyridamole stress SPECT myocardial perfusion imaging using a cadmium-zinc-telluride camera

Transient ischaemic dilation ratio thresholds in patients with zero coronary calcium score undergoing exercise or dipyridamole stress SPECT myocardial perfusion imaging using a cadmium-zinc-telluride camera

Is left ventricular systolic index the new kid in the block?

Evaluation of Ventricular Function by Nuclear Imaging

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