Transient Ischemic Dilation Ratio Research Articles

Utility of gated SPECT parameters in detection of coronary artery disease in patients with normal perfusion images

BackgroundFalse negative myocardial perfusion images on single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is a substantial problem in the interpretation of MPI. To explore possible parameters from gated SPECT that could detected coronary artery disease (CAD) in patients with normal perfusion images, we retrospectively selected patients who underwent a 2-day Tc-99 m MIBI adenosine stress/rest MPI and a subsequent invasive coronary angiography. Gated SPECT parameters, including end systolic volume (ESV), end diastolic volume (EDV), left ventricular ejection fraction (LVEF), and transient ischemic dilation (TID) ratio of patients with and without CAD were compared and assessed for their respective diagnostic performance using receiver operating characteristics (ROC) area under the curve (AUC).ResultsAmong 22 patients with normal perfusion images, 7 patients had CAD. Despite the small number of patients, we found significant differences between the ESV, the EDV, and the LVEF between patients with and without CAD. The analysis of ROC curve showed the stress ESV could excellently detect CAD (AUC = 0.900). The rest ESV, the stress EDV, the rest EDV, the stress LVEF and the rest LVEF could likewise perform well in the detection of CAD (AUC = 0.833, 0.819, 0.790, 0.862, and 0.838, respectively). In contrast, the change in LVEF and the TID ratio (AUC = 0.667 and 0.524, respectively) did not seem as reliable as other parameters. Optimal cutoffs for detection of CAD in patients with normal perfusion images from our study were ≥ 20.0 mL for the stress ESV, ≥ 71.0 mL for the stress EDV, ≤ 66.3 EF units for the stress LVEF, ≥ 18.0 mL for the rest ESV, ≥ 67.0 mL for the rest EDV and ≤ 70.0 EF unit for the rest LVEF.ConclusionsGated SPECT parameters could facilitate detection of CAD in patient with normal perfusion images on Tc-99m MIBI MPI. These parameters should be carefully interpreted to improve diagnostic accuracy and reduce false negative MPI.

Comparison of second-line on-site computed quantitative flow ratio from coronary computed tomography angiography to PET perfusion imaging for detecting obstructive coronary artery disease

Abstract Introduction In patients with suspected obstructive coronary artery disease (CAD) on coronary computed tomography (CTA), guidelines endorse second-line selective testing for hemodynamic evaluation of suspected CAD. A variety of non-invasive modalities are available, and myocardial perfusion imaging with Rubidium-82 positron emission tomography (PET) is an established method with high diagnostic performance. Recently, an on-site method estimating computed tomography-derived quantitative flow ratio (CT-QFR) showed promising results for discriminating obstructive CAD. However, no study has compared the diagnostic performances of PET and CT-QFR. Purpose To assess a possible non-inferiority of CT-QFR compared to PET in patients with suspected obstructive CAD at CTA using invasive coronary angiography (ICA) with fractional flow reserve (FFR) as reference. Methods Patients (n=1732, 57% males, age 59±9.5) referred on a clinical indication with symptoms suggestive of obstructive CAD underwent routine CTA. Patients with ≥50% diameter stenosis (DS) on CTA were referred for PET and subsequent ICA with FFR. CT-QFR was analyzed post-hoc blinded to PET and ICA results. Abnormal CT-QFR was defined as CT-QFR ≤0.80 in any vessel with a diameter ≥1.5mm. An independent core-lab evaluated PET scans as abnormal/normal with optional analyst-dependent application of pre-specified criteria; summed stress score of ≥4 in ≥2 contiguous segments, vessel-specific myocardial blood flow (MBF) <2.00 ml/g/min, global myocardial blood flow reserve ≤1.8, and/or transient ischemic dilatation ratio >1.13. Obstructive CAD was defined as ICA with FFR ≤0.80 or high-grade stenosis (≥90% DS). Results In total, 445/1732 patients (25%) had suspected obstructive CAD on CTA of whom 400/445 patients (90%) underwent subsequent PET and ICA. CT-QFR was successfully analysed in 383/400 (96%) patients classifying 174/383 (45%) patients as having disease. In comparison, PET classified 130/383 (34%) patients as having disease. In total, obstructive CAD by ICA with FFR was identified in 162 (42%) patients. There was no significant difference in area under the receiver-operating characteristic curves for CT-QFR compared to the best performing PET metric (lowest vessel-specific MBF); 0.84 (95% CI 0.80–0.89) vs. 0.81 (0.77–0.85), p=0.19)) (Fig. 1). Overall diagnostic accuracy of CT-QFR versus PET was similar (78% (95% CI 74–82) vs. 77% (72–81), p=0.70. Sensitivities for CT-QFR and PET were 78% (71–84) and 63% (55–70), p<0.01, respectively, and specificities 78% (72–84) and 87% (82–91), p=0.01, respectively (Fig. 2). Three-vessel or left main disease on ICA was correctly identified in 30/31 patients by both CT-QFR and PET. Conclusion In patients with suspected obstructive CAD by CTA, second-line CT-QFR was non-inferior to PET for discriminating obstructive CAD by invasive FFR; Although diagnostic accuracy was similar, CT-QFR demonstrated higher sensitivity while PET showed higher specificity Funding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Aarhus University PhD fellowshipRegion Mid Health Research Foundation

Transient ischemic dilation or transient RV visualization in patients with normal SPECT stress myocardial perfusion imaging: Correlation with CT coronary artery calcium scoring and coronary angiography

BackgroundAncillary findings on MPI, such as transient ischemic dilation (TID) and transient right ventricular visualization (TRV), are recognized as markers of extensive CAD and predictive of adverse outcomes. They usually occur in association with stress-induced regional MPI abnormalities. However, the clinical significance of these ancillary markers in the presence of normal stress MPI is incompletely understood. MethodsFrom a cohort of 564 consecutive patients referred for clinical SPECT stress MPI, 44 patients had normal stress SPECT MPI and either TID (n = 28) or TRV (n = 16). These imaging findings were correlated with CT coronary calcium (CAC), CT coronary angiography (CTA), and invasive coronary angiography (ICA) in patients with severe CAC ≥ 1000 HU. TID and TRV were quantified as stress/rest ratios. Severe CAD was defined as > 70% luminal stenosis on CTA or ICA. ResultsThe median TID ratio was 1.23, with a range of 1.13–1.48; the median TRV ratio was 1.30, with a range of 1.20–1.48. Of 44 patients with TID or TRV, only 9 patients (20.5%) had severe obstructive > 70% CAD by angiography (6 of 28 patients (21.5%) with TID and 3 of 16 patients (19%) with TRV). Severe multi-vessel CAD occurred in only 2 of 44 patients (4.5%). In contrast, of 9 patients with CAC > 1000 HU, 6 (67%) had severe obstructive CAD. ConclusionIn patients with normal stress SPECT MPI and TID or TRV, the incidence of severe obstructive CAD was relatively low and predominantly single-vessel CAD. These findings do not support the concept that TID or TRV with normal stress MPI is predictive of high-risk CAD.

Prediction of 2-year major adverse cardiac events from myocardial perfusion scintigraphy and clinical risk factors

BackgroundWe developed CRAX2MACE, a new tool derived from clinical and SPECT myocardial perfusion imaging (MPI) variables, to predict 2-year probability of major adverse cardiac event (MACE) comprising death, hospitalized acute myocardial infarction or coronary revascularization. MethodsConsecutive individuals with SPECT MPI 2001-2008 had two-year MACE determined from population-based health services data. CRAX2MACE included age, sex, diabetes, recent cardiac hospitalization, pharmacologic stress, stress total perfusion deficit (TPD), ischemic (stress-rest) TPD, left ventricular ejection fraction and transient ischemic dilation ratio. Two-year event rates were classified as low (< 5%), moderate (5.0-9.9%), high (10-19.9%) and very high (20% or greater). ResultsThe study population comprised 3896 individuals for the development and 1946 for the validation subgroups with subsequent MACE in 589 (15.1%) and 272 (14.0%), respectively. CRAX2MACE, derived from the development subgroups, accurately stratified MACE risk in the validation subgroup (area under the receiver operating characteristics curve 0.79) with stepwise increase in the observed event rate with increasing predicted risk category (low, 2.3%; moderate, 5.5%; high, 18.8%; very high 33.2%; P-trend < 0.001). ConclusionsA simple tool based upon clinical risk factors and MPI variables predicts 2-year cardiac events. Risk stratification between the low and very high groups was greater than tenfold.

Prognostic significance of post-stress reduction in left ventricular ejection fraction with adenosine stress in Jordanian patients with normal myocardial perfusion

BackgroundThe significance of post-stress reduction in left ventricular ejection fraction (LVEF) in patients with normal perfusion on adenosine stress/rest imaging remains controversial. MethodsConsecutive patients who underwent 2-day adenosine gated stress/rest 99mTc-sestamibi imaging and had normal perfusion were analyzed. LVEF was quantified at rest and 1 hour post-adenosine. Patients were followed up for hard (cardiac death or nonfatal MI) and soft (coronary revascularization or congestive heart failure) cardiac events for 24.1 ± 11.0 months. ResultsOf 560 patients included in the study, 135 (24.1%) had a post-stress reduction in LVEF of ≥ 5%. Rest LVEF (P < 0.001), known history of CAD (P = 0.01) and transient ischemic dilatation ratio (P = 0.02) were independent predictors of LVEF reduction. Event-free survivals were similar in patients with and without ≥ 5% LVEF reduction (P = 0.8). The unadjusted hazard ratio (95% CI) for cardiac events for ≥ 5% LVEF reduction was 1.09 (0.55-2.15), P = 0.81, while the hazard ratio adjusted for known history of CAD, smoking, post-stress LVEF and peak heart rate was 0.87 (0.44-1.75), P = 0.71. ConclusionsSignificant post-adenosine reduction in LVEF occurs in about one-fourth of patients with normal perfusion but does not confer adverse prognosis compared with patients without such reduction.

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

Abstract&#x0D; 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).&#x0D; 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.&#x0D; 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.

Upper reference limits of transient ischemic dilation ratio for different protocols on new-generation cadmium zinc telluride cameras: A report from REFINE SPECT registry

BackgroundUpper reference limits for transient ischemic dilation (TID) have not been rigorously established for cadmium-zinc-telluride (CZT) camera systems. We aimed to derive TID limits for common myocardial perfusion imaging protocols utilizing a large, multicenter registry (REFINE SPECT). MethodsOne thousand six hundred and seventy-two patients with low likelihood of coronary artery disease with normal perfusion findings were identified. Images were processed with Quantitative Perfusion SPECT software (Cedars-Sinai Medical Center, Los Angeles, CA). Non-attenuation-corrected, camera-, radiotracer-, and stress protocol-specific TID limits in supine position were derived from 97.5th percentile and mean + 2 standard deviations (SD). Reference limits were compared for different solid-state cameras (D-SPECT vs. Discovery), radiotracers (technetium-99m-sestamibi vs. tetrofosmin), different types of stress (exercise vs. four different vasodilator-based protocols), and different vasodilator-based protocols. ResultsTID measurements did not follow Gaussian distribution in six out of eight subgroups. TID limits ranged from 1.18 to 1.52 (97.5th percentile) and 1.18 to 1.39 (mean + 2SD). No difference was noted between D-SPECT and Discovery cameras (P = 0.71) while differences between exercise and vasodilator-based protocols (adenosine, regadenoson, or regadenoson-walk) were noted (all P < 0.05). ConclusionsWe used a multicenter registry to establish camera-, radiotracer-, and protocol-specific upper reference limits of TID for supine position on CZT camera systems. Reference limits did not differ between D-SPECT and Discovery camera.

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

Abstract&#x0D; 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).&#x0D; 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.&#x0D; 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).&#x0D; Patients &amp; 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 &lt;0.05 was considered as statistically significant.&#x0D; 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&lt;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 &gt;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&lt;1.19, 13(35.1%) were in MVD group and 1(7.1%) were in SVD group. The difference was statistically significant (P&lt;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&lt;0.05) between two groups.&#x0D; 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.&#x0D; Bangladesh J. Nuclear Med. 21(2): 77-80, July 2018

Computer derived transient ischemic dilation ratio for identifying extensive coronary artery disease using a CZT camera and imaging in the upright position

BackgroundTransient ischemic dilation (TID) of the left ventricle (LV) has not been validated as a marker of extensive coronary artery disease (CAD) for studies using a cadmium-zinc-telluride (CZT) camera with upright imaging. MethodsTID ratios were obtained from upright stress and rest images on a CZT camera. Separate cut-off values were determined for exercise and for regadenoson stress. The cutoffs were then applied to 28 patients with extensive CAD and 101 patients without extensive CAD. ResultsWith treadmill exercise, an upright TID ratio ≥1.16 provided a positive predictive value of 50% and a negative predictive value of 85.4% for the identification of extensive CAD. In the regadenoson group, an upright TID ratio of 1.29 provided a positive predictive value of 20% and a negative predictive value of 75.9%. Although not an independent predictor of extensive CAD in all subjects, in subjects with a normal upright LVEF, it provided a predictive value by receiver operating characteristics comparable to the SSS. ConclusionsIncreased upright TID measurements on a CZT camera are associated with extensive CAD. The upright TID measurements can serve in an adjunctive role to SSS, and may be most effective in patients with a normal upright exercise LVEF.

Transient Ischemic Dilation Ratio in Regadenoson, Single Isotope Gated Single-photon Emission Computed Tomography Myocardial Perfusion Imaging.

Single isotope 99mTc single-photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) is the most commonly used protocol for nuclear stress testing. Transient ischemic dilation of the left ventricle (TID) has been considered a specific marker of severe coronary artery disease (CAD). Recent publications have questioned the clinical utility of TID, specifically with regadenoson as a stressor and 4DM-SPECT software for TID analysis. These findings have not been demonstrated using other imaging packages. The goal of our study was to establish the TID threshold in the identification of Multi-vessel CAD using Quantitative Perfusion SPECT (QPS) software. Included in this study are 190 patients that had undergone regadenoson-stress, same day, single-isotope 99mTc MPI and had a coronary angiography within a designated 3-month period. QPS (Cedars-Sinai, LA, CA) automated image analysis software was used to calculate TID ratios which were compared across different CAD categories. Coronary angiograms were reviewed to identify both obstructive and nonobstructive CAD. The mean TID for patients with nonobstructive CAD (n = 91) was 1.02 ± 0.11, and the threshold for TID was 1.24. A receiver operating characteristic curve showed that TID had a poor discriminatory capacity to identify MVD (area under the curve 0.58) with a sensitivity of 3% and a specificity of 97%. In our study with regadenoson MPI in a predominantly African-American population, TID was found to be a poor predictor of MVD using QPS software. The reason is unclear but possibly related to the significant decline in the prevalence of severe CAD in the area where our study took place.

Relationship between gated myocardial perfusion SPECT findings and hemodynamic, electrocardiographic, and heart rate changes after Dipyridamole infusion.

After dipyridamole infusion, electrocardiographic (ECG), blood pressure and heart rate (HR) changes were seen. We tried to investigate whether there is a relationship between hemodynamic, ECG and HR changes after dipyridamole infusion and gated myocardial perfusion SPECT findings. We studied 206 consecutive patients which underwent a 2-day protocol Dipyridamole Stress/Rest Tc99m-Sestamibi gated myocardial perfusion SPECT. Systolic blood pressure (SBP), diastolic blood pressure (DBP), HR and ECG were recorded. HR was mildly increased while SBP and DBP were mildly decreased after Dipyridamole infusion. There was only statistically significant difference between ECG changes as well as transient ischemic dilation (TID) ratio between normal scans and scans with ischemia (P = 0.02 and P = 0.01 respectively). There was correlation between these variables and summed stress score (SSS) and summed difference score (SDS). Patients with ischemia in their scans, 44.3% had ST depression after Dipyridamole infusion. Also ST depression most frequently was seen in patients with left anterior descending artery disease. From patients with abnormal scan + ST depression after Dipyridamole infusion (33 patient), 27 patient (81.81%) had ischemia. There was an association between TID ratio as well as ECG changes after Dipyridamole infusion and SSS, SDS and coronary artery territory abnormality. Difference between calculated left ventricular ejection fraction using stress and rest images had significant correlation with SSS and SDS. ST depression after Dipyridamole infusion and TID ratio had association with ischemia, SSS and SDS. So in equivocal Gated SPECT findings, they could be very useful for interpretation.

Prediction of Flow-Limiting Fractional Flow Reserve in Patients With Stable Coronary Artery Disease Based on Quantitative Myocardial Perfusion Imaging

Although fractional flow reserve (FFR) and myocardial perfusion imaging (MPI) findings fundamentally differ, several cohort studies have revealed that these findings correlate. Here, we investigated whether flow-limiting FFR could be predicted from adenosine stress thallium-201 MPI with single-photon emission computed tomography (SPECT) findings derived from 84 consecutive, prospectively identified patients with stable coronary artery disease and 212 diseased vessels. Among them, FFR was measured in 136 diseased vessels (64%). The findings were compared with regional perfusion abnormalities including stress total perfusion defect (TPD)- rest TPD determined using quantitative perfusion single-photon emission computed tomography software. The FFR inversely correlated the most accurately with stress TPD- rest TPD (r=-0.552, p <0.001). Predictors of major vessels of interest comprising FFR <0.80, included stress TPD- rest TPD, the transient ischemic dilation ratio, left ventricular ejection fraction at rest and beta blockers for left anterior descending artery (LAD) regions, and stress TPD- rest TPD, left ventricular mass, left ventricular ejection fraction at rest, right coronary artery lesions, the transient ischemic dilation ratio, and age for non-LAD regions. The diagnostic accuracy of formulas to predict major vessels of interest with FFR <0.80 was high (sensitivity, specificity and accuracy for LAD and non-LAD: 84%, 87% and 86%, and 75%, 93% and 87%, respectively). In conclusion, although somewhat limited by a sample size and a single-center design, flow-limiting FFR could be predicted from MPI findings with a defined probability. A cohort study might validate our results and provide a novel adjunctive tool with which to diagnose functionally significant coronary artery disease from MPI findings.

Transischemic Dilation as Predictor for Heart Failure in SPECT Data Analysis of Patients with Heart Disease

Objectives: Transient ischemic dilation ratio (TID) of the left ventricle is a significant predictor of future cardiac events in patients with otherwise normal myocardial perfusion SPECT. TID is a marker for subendocardial perfusion reduction after exercise in gated SPECT studies. Increased TID is correlated with concentric or excentric left-ventricular hypertrophy, or increased pre- or afterload conditions. This parameter is suggested to be an indicator for deterioration of subendocardial perfusion and offers a more precise presumptive screening for myocardial dysfunction.

The significance of automatically measured transient ischemic dilation in identifying severe and extensive coronary artery disease in regadenoson, single-isotope technetium-99m myocardial perfusion SPECT

BackgroundThe critical threshold and clinical significance of transient ischemic dilation (TID) for regadenoson, single-isotope 99mTc SPECT myocardial perfusion imaging (MPI) are not defined. MethodsFrom 100 patients with low likelihood of CAD, we derived the abnormal TID threshold (mean + 2 SD). We validated the threshold in a cohort of 547 patients who received one-day, rest/regadenoson-stress, 99mTc-tetrofosmin SPECT-MPI followed by coronary angiography within 6 months. Patients were classified into three CAD severity strata: no significant CAD, mild to moderate CAD, and severe and extensive CAD. ResultsThe abnormal TID threshold was determined to be 1.31. Though mean TID ratios were different between the three CAD severity groups and the derivation cohort (P < .001), there was no difference in the mean TID ratios between the categories of CAD severity or in the prevalence of severe CAD between TID+ and TID− groups (P = .74). By ROC analysis, TID had a poor discriminatory capacity in identifying severe and extensive CAD [AUC of 0.55 (95% CI 0.47-0.62, P = .25)]. Stepwise multivariate logistic analysis demonstrated that adding TID to clinical and perfusion data did not provide incremental diagnostic value (P = .87). ConclusionsThe clinical utility of TID with regadenoson-stress MPI in this era of declining CAD burden is questionable.

CRT-406 Transient Ischemic Dilation is a Useful Marker in Screening patients for Coronary Artery Bypass Surgery

Transient ischemic dilation (TID) ratio of the left ventricle following stress, when accompanied by abnormal perfusion, is associated with severe coronary artery disease (CAD). The aim of this study is to assess the hypothesis that TID ratio is useful in screening patients who may be optimal

Correlation between transient ischemic dilatation (TID) and coronary artery disease in Saudi male patients

ObjectiveA high transient ischemic dilatation ratio (TID) for the left ventricle (LV) from a gated myocardial perfusion imaging (G-MPI) study is widely believed to be associated with significant coronary artery disease (CAD). We have investigated the relationship between TID and CAD for our male Saudi Arabian patient population. MethodsIn this retrospective study, all male Saudi Arabian patients who underwent a two-day G-MPI study using Tc99m MIBI during the year 2011 having a TID⩾1.20 were included. Quantitative perfusion and gated parameters were obtained using Cedar Sinai’s AutoQuant software version 3.0, 2003, Means of summed stress scores, summed rest scores and summed difference scores (SSS, SRS, SDS, respectively), stress and rest ejection fraction (EF) were calculated. Visual interpretation was performed to classify the perfusion as normal, fixed, mixed (fixed and reversible defects), single reversible or multiple reversible defects. Coronary angiograms were assessed as normal with no CAD, single vessel, two-vessel or three-vessel disease. Correlations between the TID and other parameters were studied using analysis of variance (ANOVA) with IBM-SPSS version 20. ResultsA total of 52 male patients had a high TID of ⩾1.20 (mean 1.30±0.13). Ten patients had a SSS of 0–3 and 16 were classified as normal by visual assessment. Stress EF (mean 50.4±12%) was lower than the rest EF (mean 56.6±12.8%) with the difference being statistically significant (Students paired t-test, p=0.001).Angiography results were available in 44 patients, 3 having a normal angiogram, 24 having three vessel disease, 7 having two vessel disease and 10 having one vessel disease. Five patients with normal perfusion and SSS=0–3 had CAD as seen on a coronary angiography. CAD on coronary angiography showed a significant correlation with perfusion abnormalities as assessed by visual interpretation (p=0.002). TID showed a significantly correlation with both perfusion abnormalities (p=0.009), as assessed by visual interpretation, and with Summed difference scores, SDS (p=0.000). ConclusionA high TID on G-MPI was a very sensitive indicator of significant CAD. In patients with normal perfusion and high TID further workup is warranted.

Impact of glycosylated hemoglobin (HBA1C) on the extent of perfusion abnormalities and left ventricular dysfunction using gated myocardial perfusion imaging and clinical outcomes in diabetic patients

The aim of the study was to determine the impact of glycosylated hemoglobin (HBA1C) on the extent of perfusion abnormalities and left ventricular dysfunction (LVD) using gated myocardial perfusion imaging (GMPI) and clinical outcomes in diabetic patients. A total of 1013 individuals (457 diabetic patients and 556 nondiabetic controls) were included in the study. Among the diabetic patients, 254 (56%) were male and 203 (44%) were female, with a mean age of 58 ± 9 years. Stress GMPI was evaluated for the size and severity of perfusion defects, transient ischemic dilation (TID) ratio (>1.22), and LVD. Patients were followed up for 22 months (12-24 months) for fatal myocardial infarction or nonfatal myocardial infarction (NFMI). GMPI was found to be normal in 49 and 68% (P<0.0001) of diabetic patients and nondiabetic controls, respectively; fixed defects were seen in 21 and 16% (P=0.049), reversible defects in 30 and 16% (P<0.0001), and TID in 19 and 8% (P<0.0001) of participants in the diabetic and nondiabetic groups, respectively. Receiver-operating characteristic curve analysis revealed the diagnostic strength of HBA1C for coronary artery disease at a cutoff value greater than 7.3% (P<0.0001). Fasting blood sugar and duration of diabetes had poor diagnostic strength (P>0.05). The diabetic cohort was divided into group A (HBA1C>7.3%) and group B (HBA1C ≤ 7.3%). GMPI in groups A and B revealed fixed defects in 33 and 9% and reversible defects in 41 and 22%, respectively; the sum stress score was 6 ± 2 and 5 ± 2, the sum thickness score was 38 ± 8 and 32 ± 6, and %left ventricular ejection fraction was 53 ± 16 and 58 ± 11, with TID in 32 and 8%, in groups A and B, respectively (all with P<0.0001). The Kaplan-Meier survival curves in groups A and B revealed event-free survival of 97.2 and 98.3% for fatal myocardial infarction (P=0.742) and 87.1 and 97.9% for NFMI (P<0.05), respectively. HBA1C is a reliable predictor of coronary artery disease and the magnitude of perfusion defects and LVD and the incidence of NFMIs are higher at an HBA1C level greater than 7.3%.

Détection des génomes de Cytomégalovirus et d’Herpès Simplex Virus dans les lavages broncho-alvéolaires au décours des pneumopathies : fréquence et interprétation

The aim of this study was to assess the effect of attenuation correction (AC) on left ventricular (LV) volumes and LV transient ischemic dilatation (TID) during dual-isotope single-photon emission computer tomographic (SPECT) myocardial perfusion imaging (MPI). Ninety-six patients (mean age 58 ± 11 years, 15% women, 38 patients completed exercise and 58 dipyridamole pharmacologic stress tests) assessed for known or suspected coronary artery disease underwent dual-isotope thallium-201 rest and technetium-99m sestamibi stress SPECT MPI with computed tomography–based AC. The TID ratio was calculated separately for non-AC and AC SPECT MPI studies as the ratio of the LV endocardial volume at stress divided by LV endocardial volume at rest. The mean and range of the gated LV ejection fraction during exercise and pharmacologic stress was 54 ± 12% (29% to 80%) and 58 ± 12% (27% to 80%), respectively. In the exercise stress group, the same mean LV endocardial volumes in non-AC and AC stress (76.4 ± 30 and 76.5 ± 28) and rest (66.3 ± 26 and 66.4 ± 24) studies were found (p = 0.90). There was no statistical difference between the mean exercise TID ratio in non-AC and AC studies (1.27 vs 1.31, respectively, p = 0.10). The same mean LV endocardial volumes in non-AC and AC in pharmacologic stress (79.9 ± 42 and 80 ± 41) and rest (71.4 ± 41 and 72.3 ± 37), respectively, were found (p = 0.50). There was no statistical difference between the mean dipyridamole TID ratio in non-AC and AC studies (1.20 vs 1.17, respectively, p = 0.10). In conclusion, LV volumes and TID indexes obtained on SPECT MPI with exercise or pharmacologic stress using dipyridamole are not affected by AC.

Preload dependence of gated cardiac SPECT-derived ventricular volumes in hemodialysis patients

BackgroundIn hemodialysis (HD) patients, the intravascular volume expansion of the pre-HD state leads to a high preload. We aim to examine its effect on myocardial perfusion gated SPECT (MPGS)-derived left ventricular (LV) volumes. MethodsThe study comprised 50 end-stage renal disease (ESRD) patients on HD with normal 2-day stress/rest MPGS performed for kidney transplantation risk assessment. Patients (pts) comprised 23 men/27 women, with mean age of 59.4 ± 7.1 years. The time elapsed from the last HD session in hours was calculated on both days, and patients were classified according to whether it was higher (group A: 19 pts), lower (group B: 27 pts), or equal (group C: 4 pts) on the stress vs the rest day. End-diastolic, end-systolic volumes (EDV, ESV), and left ventricular ejection fraction (LVEF) were determined using QGS™ software. Transient ischemic dilation (TID) ratios were derived from the nongated images using QPS™ software. ResultsVolumes were significantly higher at stress in group A, at rest in group B, and similar in group C. TID ratios were significantly higher in group A vs groups B and C. ConclusionsMPGS-derived ventricular volumes are preload dependent. The high preload of the pre-HD state may mimic ischemic TID if occurring on the stress day and create confusion if coinciding with the rest day.