Interest of the evaluation of the LV area in the evaluation of the TID in MPS through IQ SPECT

Funding Acknowledgements Type of funding sources: None. Objectives To the determine the value as ischemic indicator of measurement of left ventricular areas under stress and rest conditions in the evaluation of the transient ischemic dilation. Methodology This quantitative, observational and cross sectional study included patient undergoing myocardial perfusion SPECT/CT (MPS). Protocol 2-day exercise stress/rest, radiotracers tetrofosmin/MIBI Tc-99m, IQ- SPECT (smartzoom collimators, 17 slices, 20-sec/slice), with/without CT-based attenuation correction (NC and AC, respectively) and processing with Cedars-Sinai QPS software. A descriptive statistical analysis was performed to evaluate patient conditions; MPS results, left ventricular parameters (volume of cavity and area), transient dilation and area dilation ratios. An agreement analysis according by Blend-Altman plots and correlation analysis was realized between TID y LV areas ratios. An univariate analysis by chi square test was used to determine whether there is a statistically significant difference between the frequecies of results of precited factors and TID Results 99 patiens with MPS were included. They were categorized in two groups as 87.87% with normal TID (values : 0.9-1.26) and 12.13% with TID > 1.25 . The mean age was 62,11 ± 10.29 years old and male were 70,1%. The prevalence of clinical conditions were 62.1% of arterial hypertension , 19.5% of type-2 diabetes mellitus and 72.4% dyslipidemia. The prevalence of cardiac disease were 60.9% ischemic cardiac disease, 17.2% cardiac rhythm alterations, 27.6% of cardiac valve disease, 13.8% myocardial hypertrophy and 4.6% dilated cardiomyopathy. There were no statistically significant differences of precited parameters between the two groups. There are 9.19% mild and 2.29% moderate ischemics MPS results in the normal TID group and 36.36% mild ischemic MPS result in the TID > 1.25 group. (p < 0.05) In the normal TID group the stress /rest area ratios were 1.016 ± 0.13 for NC studies and 1.016 ± 0.12 for AC studies (p > 0.05). In the TID > 1.25 group the stress /rest area ratios were 1.13 ± 0.05 for NC studies and 1.12 ± 0.08 for AC studies (p > 0.05) The normal values limits 1.016 ± 0.26 for NC studies and 1.016 ± 0.24 for AC studies. The agreement using the Bland-Altman method showed that the mean difference between TID and stress/rest ratios by NC and AC studies was 0.02 ± 0.08 (-0.13 to 0.18; 95% confidence interval) and 4.04% within the 95% confidence interval. Pearson correlation coefficient obtained between TID and area ratios was 0.69 in the NC studies and 0.91 in AC studies. This is consistent with the recommendations for studies with detectors SMARTZOOM would advise the use of AC determinations. Conclusions The presence of left ventricular areas within normal values in patients with TID visualized in MPS suggests the existence of endocardial ischemia and no ventricular dilation. The joint assessment of these parameters adds value in those situations.

Coronary microvascular dysfunction: An important interpretation on the clinical significance of transient ischemic dilation of the left ventricle on myocardial perfusion imaging

PURPOSE: To further investigate the clinical significance of transient ischemic dilation (TID) on myocardial perfusion imaging (MPI) by analyzing the effect of anisodamine hydrobromide (a drug that can effectively ameliorate microcirculation) on the patients with isolated TID and the findings of previous literatures. METHODS: Total 107 patients with isolated TID (TID value≥1.11) were randomly divided into group A (n = 36; intravenous administration of anisodamine hydrobromide), group N (n = 36; intravenous administration of isosorbide dinitrate), and group C (n = 35; intravenous administration of normal saline). MPI and treadmill exercise test (TET) were performed again after 14-day course of intervention. Pre- and post-intervention frequencies of symptom were recorded. RESULTS: In group A, after intervention of anisodamine hydrobromide, the summed stress score (SSS) and TID value on MPI significantly decreased than those before intervention (P < 0.001), the durations of exercise (DEs) and metabolic equivalents (METs) in TET notably ascended (P < 0.001), as well as the symptom remarkably improved. In group N and group C, there were no significant differences in SSS, TID value, DEs, METs, and frequencies of symptom between pre- and post-intervention (P > 0.05). No significant improvement of symptoms in group N before and after treatment. CONCLUSIONS: TID with perfusion defect may usually predict a possibility of severe and extensive coronary artery disease (CAD). An isolated TID should be considered as a likelihood of coronary microvascular dysfunction (CMD). TET and coronary CT angiography (cCTA) are extremely helpful for the antidiastole on CAD and CMD. The administration of anisodamine hydrobromide might be an optional treatment for the patients with isolated TID.

Transient ischemic dilation as a diagnostic marker in myocardial perfusion SPECT protocols: a systematic review and meta-analysis

Background: Transient ischemic dilation (TID) measures left ventricle (LV) volume changes which can be associated with combination of myocardial and endocardial ischemia. Various stress methods, single photon emission computerized tomography (SPECT) imaging protocol, camera and software incite controversy on TID cut off. The purpose of this study was to evaluate the TID ratio in detection of coronary artery disease (CAD) categories in a systematic review and meta-analysis. Method: We conducted a systematic search of electronic databases (PubMed, Scopus, Embase and Web of Science) up to 1 January 2017. The reference lists of all included studies were searched for a higher accuracy. The search strategy was according a defined PICO as P: none, I: Transient ischemic dilation, O: Coronary Artery Diseases, C: Angiographies. Statistical analysis was done by Comprehensive meta-analysis software version 2 (CMA-2). Result: After study selection process, 7 studies were selected for data extraction. TID was studied from 1987. The sample size of included studies ranged between 86 and 545. The mean age of included patients varied between 58 and 69 years old. Ranges of TID in CAD categories were excluded. The pooled estimates of TID in single and dual pharmacological stress test in three CAD categories were calculated. Conclusion: Our findings show that more studies are needed to compare the TID variability. Although in this study meta-analysis was done and TID was summarized from studies but the software differences were ignored.

Transient ischemic dilation as a diagnostic marker in myocardial perfusion SPECT protocols: a systematic review and meta-analysis

Background: Transient ischemic dilation (TID) measures left ventricle (LV) volume changes which can be associated with combination of myocardial and endocardial ischemia. Various stress methods, single photon emission computerized tomography (SPECT) imaging protocol, camera and software incite controversy on TID cut off. The purpose of this study was to evaluate the TID ratio in detection of coronary artery disease (CAD) categories in a systematic review and meta-analysis. Method: We conducted a systematic search of electronic databases (PubMed, Scopus, Embase and Web of Science) up to 1 January 2017. The reference lists of all included studies were searched for a higher accuracy. The search strategy was according a defined PICO as P: none, I: Transient ischemic dilation, O: Coronary Artery Diseases, C: Angiographies. Statistical analysis was done by Comprehensive meta-analysis software version 2 (CMA-2). Result: After study selection process, 7 studies were selected for data extraction. TID was studied from 1987. The sample size of included studies ranged between 86 and 545. The mean age of included patients varied between 58 and 69 years old. Ranges of TID in CAD categories were excluded. The pooled estimates of TID in single and dual pharmacological stress test in three CAD categories were calculated. Conclusion: Our findings show that more studies are needed to compare the TID variability. Although in this study meta-analysis was done and TID was summarized from studies but the software differences were ignored.

Evaluation of Transient Ischemic Dilation (TID) Ratio in Gated SPECT Myocardial Perfusion Imaging (MPI) with Pharmacological Stress Agents

Objectives: Transient ischemic dilation (TID) refers to an apparent increase in the size of the left ventricular cavity on stress myocardial perfusion imaging compared to rest imaging. This study was performed to correlate the value of TID ratio in gated SPECT MPI in Coronary Artery Disease (CAD). Patients & Methods: Seventy-four suspected or known CAD patients underwent MPI performed with Tc-99m sestamibi. Single day stress - rest protocol with pharmacological stress was followed, according to established practicing protocol of NINMAS. A statistical analysis was carried out by using the Statistical Package for Social Sciences version 20.0 for Windows (SPSS Inc., Chicago, Illinois, USA). Student t-test was used for continuous variables. Chi-square test used to compare categorical data. P values <0.05 was considered as statistically significant. Results: Among 74 patients, 63(85.1%) were male and 11(14.9%) were female. The mean age found to be 53.8±10.5 years. Majority (90.5%) patients had hypertension, 45(60.8%) had diabetic mellitus and 39(52.7%) had dyslipidemia in blood lipid profile, 44(59.5%) were past smoker. The mean ejection fraction was 44.6±14.6 percent. The mean abnormal TID ratio was 1.25 ± 0.35 in patients having abnormal MPI findings and 1.03±0.21 in having normal MPI findings. The difference was statistically significant (p<0.05) between two groups. It was also observed that in three cases having normal MPI had high TID ratio.Among the patients with TID ratio >1.19, 24(64.9%) patients were in MVD group and 13(92.9%) were in SVD group. Whereas among the patients with TID ratio<1.19, 13(35.1%) were in MVD group and 1(7.1%) were in SVD group. The difference was statistically significant (P<0.05) between two groups. The mean TID ratio was 1.08±0.21 in single vessel disease and 1.24±0.26 in multiple vessel disease. The difference was also statistically significant (p<0.05) between two groups. Conclusion: This study suggests that the TID ratios could provide incremental diagnostic information to standard myocardial perfusion analysis for the identification of severe and extensive disease in patients with suspected or known CAD. Bangladesh J. Nuclear Med. 21(2): 77-80, July 2018