Reference values for left ventricular systolic synchrony according to phase analysis of ECG-gated myocardial perfusion SPECT.

BACKGROUND: The aim of this study was to define reference values for left ventricular systolic synchrony and for the volume parameters of the left ventricle using myocardial perfusion SPECT-derived phase analysis method. METHODS: We evaluated data of 433 patients who underwent myocardial perfusion SPECT/CT during January 2012-February 2013 in Kuopio University Hospital. The final study population consisted of 52 patients (aged 42-84 years) who met the criteria: (1) no previously diagnosed cardiac disease, (2) normal ECG at rest, (3) no advanced coronary artery disease in CT and 4) normal myocardial perfusion in stress/rest myocardial perfusion SPECT/CT. The severity of mechanical dyssynchrony was assessed by phase analysis of gated myocardial SPECT at stress stage after pharmacological exercise and at rest using Quantitative Gated SPECT (QGS) software. Volume parameters of the left ventricle were also assessed. RESULTS: The phase histogram bandwidth at rest was 28.0 [63.7] degrees (median [95th percentile]). The standard deviation of phase histogram at rest was 7.8 [26.5] degrees. Entropy at the rest study was 54.0 [63.7] %. All left ventricular dyssynchrony parameters were statistically significantly higher at stress compared to rest. There were no statistically significant differences in dyssynchrony values between men and women. In volume parameters, reference values in male were expectedly higher than in female. Cardiac output did not differ significantly between genders. CONCLUSION: In subjects without signs of cardiac diseases, the left ventricular systolic function is well synchronized. Phase analysis measurement does not depend on gender, age, BMI or blood pressure, but the values of dyssynchrony parameters increase during pharmacological stress.

Effects of myocardial perfusion abnormalities on the accuracy of left ventricular volume and ejection fraction measured by thallium-201 gated single-photon emission tomography: comparison with echocardiography as the reference standard.

BACKGROUND: We assessed the accuracy of left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF) using quantitative gated single-photon emission computed tomography (QGS) in comparison with echocardiography as the reference standard. We also assessed the effects of total perfusion deficit (TPD) on the accuracy of QGS measurements. METHODS: A total of 258 patients underwent single-photon emission computed tomography and transthoracic echocardiography within 4 weeks of each investigation for evaluating coronary artery disease. Patients were divided into four groups according to TPD scores. RESULTS: There were 138 patients with no/minimal TPD, 64 patients with small TPD, 35 patients with middle TPD, and 21 patients with large TPD. There were good correlations and agreements in EDV (r=0.87, 0.90, 0.71, and 0.94, respectively), ESV (r=0.92, 0.94, 0.79, and 0.94, respectively), and EF (r=0.61, 0.79, 0.61, and 0.83, respectively) between QGS and echocardiography in patients with any TPD. QGS significantly underestimated EDV and ESV in patients with no/minimal or small TPD, and significantly overestimated ESV in patients with large TPD. QGS significantly underestimated EF in patients with middle or large TPD. CONCLUSION: Our results suggest that QGS is a useful tool for assessing the left ventricular volume and function in patients with any TPD, but myocardial perfusion abnormalities should be taken into consideration when interpreting QRS measurements.

Gender- and age-related differences in rest and post-stress left ventricular cardiac function determined by gated SPECT.

Gender- and age-related changes of left ventricular (LV) function and dimensions have not been elucidated in a large population by gated SPECT. Thus, the aim of this study was to derive male and female reference limits for left ventricular functional parameters, and determine the effect of age on LV dimensions and systolic function for this imaging modality. 1,639 (53% males) subjects without cardiovascular disease who underwent cardiac SPECT between January 2002 and June 2012 were included in this study. Mean age at presentation was 61 ± 12 years (range 18-92 years). A significant effect of age (p = 0.011) and gender (p < 0.0001) on resting LV ejection fraction (LVEF) was observed, with an increase in LVEF with age being more pronounced in women (ΔB-coefficient: -0.088, p = 0.011). Overall, mean LVEF was higher in women compared to men (70.3 ± 8.6% vs. 64.4 ± 7.5%, p < 0.0001). LVEF after pharmacological stress with adenosine was significantly lower than at rest in both women and men (∆LVEF = 1.1% in males and ∆LVEF = 1.6% in females, p = 0.01), which was the result of a significant increase in end-systolic volume after stress (p = 0.0001). With advancing age an increase in LVEF was observed that was more pronounced in women than in men. These findings indicate that the evaluation of cardiac function and volumes of patients by gated SPECT should consider age- and gender-matched normative values.

Comment on "Analysis of the diastolic function by myocardial perfusion gated SPECT after coronary revascularization in acute myocardial infarction" / Comentario a "Análisis de la función diastólica mediante gated-SPECT de perfusión miocárdica tras revascularización coronaria en el infarto agudo de miocardio"

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A comparison of the diagnostic performance of the ST/HR hysteresis with cardiopulmonary stress testing parameters in detecting exercise-induced myocardial ischemia.

BACKGROUND: Because ST segment depression has limited diagnostic performance at exercise electrocardiography (ECG), ST segment depression/heart rate (ST/HR) hysteresis and cardiopulmonary exercise test (CPET)-derived parameters have been proposed as alternatives to diagnose exercise-induced myocardial ischemia. We compared the diagnostic performance of such parameters. METHODS: We studied 56 subjects (45 men, 11 women, age 59.7 ± 13.6 years) referred for suspected exercise-induced myocardial ischemia with an equivocal ECG exercise test. All subjects serially underwent CPET and a myocardial single-photon emission computerized tomography (SPECT) perfusion imaging (as the gold standard for ischemia). Maximum ST depression at peak exercise (ST-max), the ST/HR hysteresis, ΔVO2/ΔWR b-b1 slope, ΔVO2/ΔWR (aa1-bb1), VO2/HR flattening duration and other CPET parameters were derived in all subjects. RESULTS: On the basis of SPECT, 23 subjects (41%) were considered ischemic and 33 subjects (59%) non-ischemic. ST/HR hysteresis was higher (0.026 mV; 95% CI: 0.003 to 0.049 vs -0.016 mV; 95% CI: -0.031 to -0.001 mV) and ST-max was lower (-0.105 mV; 95% CI: -0.158 to -0.052 vs 0.032 mV; 95% CI: -0.001 to -0.066 mV) in ischemic vs non-ischemic subjects (P=0.004 and P=0.001, respectively). Among CPET parameters, ΔVO2/ΔWR b-b(1) slope was lower (9.4 ± 3.8) and ΔVO2/ΔWR (aa(1)-bb(1)) was higher (2.1 ± 2.6) in ischemic vs non-ischemic subjects (11.4 ± 2.3, P=0.005, and 1.1 ± 1.5, P=0.001, respectively). The ST/HR hysteresis had the highest area under the curve value, better (P<0.05) than any other parameters tested, thus showing the highest overall diagnostic performance. CONCLUSION: The ST/HR hysteresis is superior to CPET-derived parameters for detecting exercise-induced myocardial ischemia in patients with equivocal ECG exercise test results.

Comparison of software programs for the assessment of left ventricular ejection fraction using 99mTc-tetrofosmin-gated SPECT/CT: correlation with equilibrium radionuclide ventriculography in the Indian population.

OBJECTIVE: The goal of this study was to compare Emory Cardiac Toolbox (ECTb), quantitative gated SPECT (QGS), four-dimensional single photon emission computed tomography (4D-MSPECT) and Myometrix cardiac software programs for the assessment of left ventricular ejection fraction (LVEF) using 99mTc-tetrofosmin-gated SPECT/CT [myocardial perfusion SPECT (MPS)] and correlate them with the LVEF values derived from equilibrium radionuclide ventriculography (ERNV) in patients with known/suspected coronary artery disease (CAD). MATERIALS AND METHODS: A total of 109 patients (80 men, 29 women) were recruited into the study. Fifty-five patients had known CAD and 54 were referred with suspicion of CAD. All the patients underwent ERNV and MPS as per the standard protocol. ERNV was processed using the vendor-provided 'EF analysis' and gated MPS was processed using individual software programs. RESULTS: The mean LVEF on ERNV was 47.9 ± 15.5%. The mean LVEF values for ECTb, QGS, 4D-MSPECT and Myometrix were 51.5 ± 19.6, 51.0 ± 18.6, 57.1 ± 19.3 and 49.7 ± 19%, respectively. On correlation analysis, a very strong positive correlation was observed between LVEF values derived by ERNV and those derived by the MPS software programs: ECTb (r=0.842, P<0.0001), QGS (r=0.835, P<0.0001), 4D-MSPECT (r=0.830, P<0.0001) and Myometrix (r=0.875, P<0.0001). Significant correlation was also seen for LVEFs among the four software programs. Normal cutoff values for ejection fraction on ECTb, QGS, 4D-MSPECT and Myometrix were 56, 52, 54 and 51%, respectively, using a 50% or more cutoff value on ERNV. CONCLUSION: A strong correlation was observed among ECTb, QGS, 4D-MSPECT and Myometrix software programs when compared with ERNV and also between them for assessment of LVEF. However, there are subtle differences in the objective values of ejection fraction generated by individual software, which must be taken into account for clinical studies.

Reproducibility of planar (123)I-meta-iodobenzylguanidine (MIBG) myocardial scintigraphy in patients with heart failure.

PURPOSE: Despite its high prognostic value, widespread clinical implementation of (123)I-meta-iodobenzylguanidine (MIBG) myocardial scintigraphy is hampered by a lack of validation and standardization. The purpose of this study was to assess the reliability of planar (123)I-MIBG myocardial scintigraphy in patients with heart failure (HF). METHODS: Planar myocardial MIBG images of 70 HF patients were analysed by two experienced and one inexperienced observer. The reproducibility of early and delayed heart-to-mediastinum (H/M) ratios, as well as washout rate (WR) calculated by two different methods, was assessed using the intraclass correlation coefficient (ICC) and the Bland-Altman analysis. In addition, a subanalysis in patients with a very low H/M ratio (delayed H/M ratio <1.4) was performed. The delayed H/M ratio was also assessed using fixed-size oval and circular cardiac regions of interest (ROI). RESULTS: Intra- and interobserver analyses and experienced versus inexperienced observer analysis showed excellent agreement for the measured early and delayed H/M ratios and WR on planar (123)I-MIBG images (the ICCs for the delayed H/M ratios were 0.98, 0.96 and 0.90, respectively). In addition, the WR without background correction resulted in higher reliability than the WR with background correction (the interobserver Bland-Altman 95 % limits of agreement were -2.50 to 2.16 and -10.10 to 10.14, respectively). Furthermore, the delayed H/M ratio measurements remained reliable in a subgroup of patients with a very low delayed H/M ratio (ICC 0.93 for the inter-observer analysis). Moreover, a fixed-size cardiac ROI could be used for the assessment of delayed H/M ratios, with good reliability of the measurement. CONCLUSION: The present study showed a high reliability of planar (123)I-MIBG myocardial scintigraphy in HF patients, confirming that MIBG myocardial scintigraphy can be implemented easily for clinical risk stratification in HF.

Sex-specific normal limits of left ventricular ejection fraction and volumes estimated by gated myocardial perfusion imaging in adult patients in Taiwan: a comparison between two quantitative methods.

BACKGROUND: The left ventricular (LV) ejection fraction (EF) and end-diastolic and end-systolic volumes are strong predictors for prognosis of cardiac death. Quantitative-gated myocardial perfusion single-photon emission computed tomography (SPECT) is widely used to measure LV functional parameters. However, systematic differences may exist between referred populations. We sought to derive sex-specific normal values for LV functional parameters obtained using two quantitative methods. METHODS: Among 1044 consecutive patients who underwent dipyridamole stress myocardial perfusion-gated 201Tl SPECT in 2008, a total of 140 (56 men) with normal perfusion imaging were selected. None had cardiac diseases or experienced cardiac events during 1-year follow-up. LV EF and end-diastolic and end-systolic volumes were calculated by quantitative-gated SPECT (QGS) and four-dimensional-myocardial single photon emission computed tomography (4D-MSPECT), respectively. RESULTS: There was excellent intrareader and interreader reproducibility for both QGS and 4D-MSPECT algorithms. The differences in LV volumes and EF between the software packages were small. High prevalence of small heart was noted in the study population, especially in women (>60%). Volumetric measures were significantly greater (P<0.001) in men than in women, even after adjustment for body surface area. Women had a higher LV EF than men when using QGS methods, but not when using the 4D-MSPECT method. Compared with 4D-MSPECT, sex remained significantly associated with EF determined by QGS methods, independent of age and body weight. CONCLUSION: LV functional parameters determined by means of gated 201Tl SPECT need to be corrected for sex and algorithms. Separate reference values of LV EF and volumes need to be applied in both women and men depending on the software package used.

Resting electrocardiogram and stress myocardial perfusion imaging in the determination of left ventricular systolic function: an assessment enhancing the performance of gated SPET.

This study aimed to determine systolic dysfunction and estimate resting left ventricular ejection fraction (LVEF) from information collected during routine evaluation of patients with suspected or known coronary heart disease. This approach was then compared to gated single photon emission tomography (SPET). Patients having undergone stress (201)Tl myocardial perfusion imaging followed by equilibrium radionuclide angiography (ERNA) were separated into derivation (n=954) and validation (n=309) groups. Logistic regression analysis was used to develop scoring systems, containing clinical, electrocardiographic (ECG) and scintigraphic data, for the discrimination of an ERNA-LVEF<0.50. Linear regression analysis provided equations predicting ERNA-LVEF from those scores. In 373 patients LVEF was also assessed with (201)Tl gated SPET. Our results showed that an ECG-Scintigraphic scoring system was the best simple predictor of an ERNA-LVEF<0.50 in comparison to other models including ECG, clinical and scintigraphic variables in both the derivation and validation subpopulations. A simple linear equation was derived also for the assessment of resting LVEF from the ECG-Scintigraphic model. Equilibrium radionuclide angiography-LVEF had a good correlation with the ECG-Scintigraphic model LVEF (r=0.716, P=0.000), (201)Tl gated SPET LVEF (r=0.711, P=0.000) and the average LVEF from those assessments (r=0.796, P=0.000). The Bland-Altman statistic (mean+/-2SD) provided values of 0.001+/-0.176, 0.071+/-0.196 and 0.040+/-0.152, respectively. The average LVEF was a better discriminator of systolic dysfunction than gated SPET-LVEF in receiver operating characteristic (ROC) analysis and identified more patients (89%) with a

Automated detection of left ventricular dyskinesis by gated blood pool SPECT.

OBJECTIVE: The ability to detect left ventricular (LV) apical dyskinesis, the hallmark of an aneurysm, is an important requirement of diagnostic cardiac imaging modalities that perform wall motion analysis. Our investigation assessed the ability of gated blood pool single-photon emission-computed tomography (GBPS) to automatically detect LV dyskinesis, using cardiac magnetic resonance (CMR) as the reference standard. MATERIALS AND METHODS: GBPS data were analyzed for 41 patients with congestive heart failure or cardiomyopathy and compared with ECG-gated TrueFISP CMR evaluations. An experienced nuclear cardiologist without the knowledge of quantitative GBPS or CMR results graded visual impressions of regional wall motion while examining cinematic playbacks of GBPS images. GBPS algorithms automatically isolated LV counts and computed regional phase (phi) values in each of 17 conventional American Heart Association LV segments. LV asynchrony was quantified by the two local measures: maximum apical phi difference (Deltaalpha), and standard deviation among apical phases (sigmaalpha), and by the five global measures: varphi histogram bandwidth (BWHistogram), phi histogram standard deviation (sigmaHistogram), Z-scores, Entropy, and Synchrony. For CMR data, an expert manually drew endocardial LV outlines to measure regional wall motion in 17 LV segments. RESULTS: Apical dyskinesis was present in nine patients. Among GBPS measurements, the method with the greatest accuracy for detecting dyskinesis was Deltaalpha (receiver operating characteristic area=95%). The only method with a sufficiently high kappa statistic to represent 'very good agreement' with CMR was Deltaalpha, with kappa=0.81. Deltaalpha was more sensitive in detecting dyskinesis than visual analysis (100 vs. 33%, P=0.01). CONCLUSION: Automatic GBPS computations accurately identified patients with LV dyskinesis, and detected dyskinesis more successfully than did visual analysis.

Recomendaciones sobre las indicaciones clínicas de la gated-SPECT de perfusión miocárdica / Recommendations on clinical indications for myocardial perfusion gated SPECT

Desde 1999 no se había realizado ninguna revisión de las Guías de actuación clínica de la Sociedad Española de Cardiología en Cardiología Nuclear, por lo que en este artículo exponemos las indicaciones clase I y IIa de la American College of Cardiology/American Heart Association/American Society of Nuclear Cardiology (ACC/AHA/ASNC) con nivel de evidencia A o B, junto con las 27 indicaciones consideradas adecuadas por el Comité de expertos de la American College of Cardiology Foundation/American Society of Nuclear Cardiology (ACCF/ASNC) y los comentarios que hemos considerado oportuno añadir los firmantes de este artículo (AU)

The Spanish Society of Cardiology's Clinical Practice Guidelines on Nuclear Cardiology have not been revised since 1999. Correspondingly, this article describes the class-I and class-IIa indications of the American College of Cardiology (ACC)/American Heart Association (AHA)/American Society for Nuclear Cardiology (ASNC), which have a grade-A or grade-B level of supporting evidence. In addition, details are given of the 27 appropriateness criteria of the American College of Cardiology Foundation (ACCF)/ASNC expert committee, along with additional comments which the authors of this review thought were appropriate to make at this time (AU)