Validation of quantitative gated single photon emission computed tomography and an automated scoring system for the assessment of regional left ventricular systolic function

A Comparison between Quantitative Gated Myocardial Perfusion Scintigraphy and Strain Echocardiography as Indicators of Ventricular Functions in Patients with Anterior Myocardial Infarction

The purpose of this study is to compare the strain echocardiographic and scintigraphic parameters for evaluating of the left ventricular (LV) functions in patients with anterior myocardial infarction (MI). Fifty-four patients (male/female: 36/18; mean age 62 ± 13 years) with anterior MI were prospectively enrolled. All patients were performed gated myocardial perfusion scintigraphy gated single-photon emission computed tomography (GSPECT) and echocardiography (EC). GSPECT data were processed and analyzed using 4D-MSPECT (4DM, Invia Medical Imaging Solutions, Ann Arbor, MI, USA). The echocardiographic strain (S) and strain rate (SR) values were calculated. The results obtained by these techniques were compared each other. A total of 918 segments of LV wall were evaluated. In all patients, 385 segments were automatically scored as normokinetic, 206 as hypokinetic, 122 as akinetic, 205 as dyskinetic and 300 as normal thickening, 348 as decrease thickening and 270 as no thickening. The means of S and SR values in thickening and motion score groups according to GSPECT were statistically different from each other (P < 0.001). There was a negative significant correlation between LV wall thickening sum score and S and SR and between LV wall motion sum score and S and SR (P < 0.001). There was a good correlation between GSPECT and echocardiographic LV-ejection fraction (r = 0.7, P < 0.001). GSPECT and strain EC are similar in quantitative grading of the severity of regional and global myocardial dysfunction in patients with anterior MI and these techniques provide valuable diagnostic information.

Analysis of the effects of electroacupuncture at the pericardium 6 acupoint on heart function in patients with angina using equilibrium radionuclide angiocardiography quantity analysis technique

OBJECTIVE

To analyze changes in cardiac function indices after electroacupuncture (EA) at the pericardium 6 (PC-6) acupoint using the equilibrium radionuclide angiocardiography (ERNA) quantity analysis technique.

DESIGN

Analysis of clinical outcomes after EA at PC-6 measured by ERNA.

SETTING

The study was conducted in a hospital.

PARTICIPANTS

31 participants (17 patients with angina and 14 healthy volunteers).

INTERVENTION

The study used ERNA to study outcomes of EA at PC-6 on heart function.

OUTCOME MEASURE

ERNA images were taken before the treatment (T0), at the end of the treatment (T1), and 20 minutes after the treatment (T2) and then processed.

RESULTS

Regional left ventricular ejection fraction (REF) increased after EA in the angina and control groups. REF at T2 was significantly higher than at T1 in the angina group (p<.01). In the control group, REF was higher at T1 than at T0 (p<.01) but did not differ between T1 and T2 (p=.08). The REF deviation among ventricular regions in the angina group was significantly greater than that in the control group at T0 (p<.01) but was reduced to the level of that in control group after EA (p=.52). Peak filling rate was lower in the angina group than in controls at all three time points (all p<.01). After EA, peak filling rate increased markedly in the angina group but not in the control group. The cardiac cycle was shorter in the angina group than in the control group at T0 (p<.01) and increased after EA. The cardiac cycle of the control group did not change.

CONCLUSION

Effects of EA at PC-6 on heart function can be detected and quantified by ENRA.

Computerized left ventricular regional ejection fraction analysis for detection of ischemic coronary artery disease with multidetector CT angiography

Regional ejection fraction (REF) provides important functional information of the left ventricular regional myocardium. We aimed to test the diagnostic accuracy of computerized REF analysis for detecting the ischemia and significant stenosis with multidetector CT angiography (MDCT). This is a retrospective study including 155 patients who underwent MDCT scans for evaluation of coronary artery disease. Among them, 83 patients also underwent SPECT imaging and invasive coronary angiography (ICA). Two groups of patients were defined: Control group with 0 coronary artery calcium and normal global and regional ventricular function, and comparison group. REF measurement was performed on all patients using computerized software. Control group REF measurements will be used as reference standard (mean-2SD REF/mean global ejection fraction) to define abnormal REF. The sensitivity, specificity, positive and negative predictive value of REF in detecting perfusion defects (fixed and reversible) was 73, 80, 75 and 79 % respectively, in a patient based analysis of comparison group. The diagnostic accuracy of REF in predicting significant stenosis (>50 %) on ICA compared with SPECT was 72 versus 61 % and 85 versus 79 % in patient and vessel based analysis of comparison group, respectively. ROC curve analysis showed REF to be a better predictor of perfusion defects on SPECT compared with significant stenosis (>50 %) alone or stenosis combined with REF (P < 0.05). The computerized assessment of REF analysis is comparable to SPECT in predicting ischemia and a better predictor of significant stenosis than SPECT. This study also provides reference standard to define abnormal values.

Helical heart on ECG gated 99mTc-tetrofosmin SPECT: counterclockwise rotation of lesion axis on wall thickening polar map as compared with that on perfusion polar map in patients with coronary artery disease

OBJECTIVE

The location of a myocardial lesion on a wall thickening polar map often does not coincide with the location of the lesion on a perfusion polar map, especially when the myocardial lesion is located at the mid cardiac region. The purpose of this study was to determine the frequency and extent of discrepancy in the location of the lesion between perfusion and wall thickening polar maps on gated single photon emission computed tomography (SPECT) using lesion axis angle (LAA).

METHODS

One hundred and forty-seven consecutive patients (male : female = 80 : 67, age range: 41-96 years) who underwent myocardial gated (99m)Tc-tetrofosmin SPECT on the suspicion of myocardial ischemia or infarct between September 2003 and September 2008 and showed both reduced myocardial perfusion and wall thickening on gated SPECT at mid cardiac region were reviewed. LAA, which is the angle between the lesion axis on perfusion and wall thickening polar maps, was measured for the patients who showed a discrepancy in lesion axis between the two polar maps. LAA was said to have a positive value when the lesion axis of the wall thickening polar map showed a counterclockwise angular rotation as compared with that of a perfusion polar map. The patients with LAA of less than 10 degrees were considered as having no lesion axis discrepancy between perfusion and wall thickening polar maps. LAA was correlated with left ventricular ejection fraction (LVEF) on gated SPECT using Pearson's correlation. Furthermore, two groups, one with LAA of >or=10 degrees and the other with LAA less than 10 degrees were correlated with dichotomous groups with >or=50% and less than 50% LVEF, using the chi(2) test. Then, 35 patients with acute coronary syndrome (ACS group) were analyzed separately for correlation between LAA and LVEF.

RESULTS

The mean +/- SD of LAA was 44.31+/-30.77 degrees (range: 0-145 degrees ). LAA was 0-10 degrees in 25 patients, 11-30 degrees in 24 patients, 31-60 degrees in 58 patients, 61-90 degrees in 30 patients, and >90 degrees in 10 patients. In addition, the lesion axis of the wall thickening polar map as compared with that of the perfusion polar map was rotated in the counterclockwise direction in 122 patients and not rotated in 25 patients. LVEF on gated SPECT showed positive correlation with LAA (P = 0.000147). In addition, there was statistically significant correlation (P = 0.001) when the two groups with LAA of >or=10 degrees and less than 10 degrees , respectively, were correlated with the groups of >or=50% and less than 50% LVEF. For the ACS group, the mean +/- SD of LAA was 45.88+/-30.30 degrees (range: 0-135 degrees ) and LVEF showed positive correlation with LAA (P = 0.0001). There was no significant statistical difference concerning LAA and LVEF between ACS group and non-ACS group (P = 0.725 and P = 0.473, respectively).

CONCLUSION

In most of our patients with coronary artery disease, the lesion axis of reduced wall thickening was rotated in the counterclockwise direction as compared with that of reduced perfusion on SPECT polar maps, especially when the myocardial lesion was at mid cardiac region. The LAA decreased as the LVEF decreased. This might be related to spatiotemporal distortion of myocardial contraction mentioned in the helical heart concept.

Global and regional evaluation of systolic and distolic left ventricular temporal parameters using a novel program for ECG-gated myocardial perfusion SPECT

BACKGROUND

A newly developed program, named cardioGRAF, enabled the evaluation of left ventricular (LV) systolic and diastolic temporal parameters for the estimation of heart failure using ECG-gated myocardial perfusion SPECT (GMPS).

OBJECTIVE

The feasibility of those global (g-) and regional (r-) parameters was validated to compare with gated equilibrium radionuclide angiography (ERNA) and speckle-tracking radial strain (STS) from echocardiography.

METHODS

Thirty-three patients were studied using GMPS and ERNA (n=11) or GMPS and STS (n=22). The following g- or r-parameters obtained by cardioGRAF and ERNA or STS were compared: time to end systole (TES), time from end systole to peak filling rate (TPF1), time from 0 to peak filling rate (TPF2), time to peak radial strain (TPS), time from peak strain to peak negative strain rate (TP-SR1), and time from 0 to peak negative strain rate (TP-SR2).

RESULTS

All g-parameters were successfully obtained by cardioGRAF and ERNA. The results demonstrated good correlations (g-TES: r = 0.79, p < 0.005; g-TPF1: r = 0.75, p < 0.02; TPF2: r = 0.83, p < 0.005). The differences were 11.9 +/- 31.8 ms in g-TES, 19.9 +/- 65.4 ms in g-TPF1, and 37.7 +/- 67.4 ms in g-TPF2. All r-parameters were successfully obtained by cardioGRAF. Eight patients and 12 segments were excluded because of the inadequate quality of routine echocardiography for STS analysis. However, r-parameters obtained by cardioGRAF were significantly correlated with those of STS (r-TES and r-TPS: r = 0.61, p = 1 x 10(-8); r-TPF1 and r-TP-SR1: r = 0.69, p = 3 x 10(-11); r-TPF2 and r-TP-SR2: r = 0.76, p = 2 x 10(-15)). The differences were 22.1 +/- 38.2 ms between r-TES and r-TPS, 7.0 +/- 123.4 ms between r-TPF1 and r-TP-SR1, and 38.1 +/- 111.5 ms between r-TPF2 and r-TP-SR2.

CONCLUSION

The feasibility of evaluating systolic and diastolic temporal parameters by a new program was validated. This program has the potential to evaluate both diastolic and systolic heterogeneous wall motions which express dyssynchrony in heart failure.

Quantification of left ventricular regional functions using ECG-gated myocardial perfusion SPECT —validation of left ventricular systolic functions—

OBJECTIVE

We have developed a program to quantify regional left ventricular (LV) function and wall motion synchrony using ECG-gated myocardial perfusion SPECT (MPS). This preliminary study was undertaken to validate the use of this program for estimating regional LV systolic function.

METHODS

Patients were subjected to MPS by 99mTc-sestamibi at rest. The study included 20 patients who were confirmed to have a low probability of coronary artery disease (LPG; low probability group), 19 heart disease patients who were examined by MPS and equilibrium radionuclide angiography (ERNA) (ERG; ERNA group), and 24 patients who were examined by MPS and 2-dimensional echocardiography (2DE) (2DEG; 2DE group). The values of the ejection fraction (EF) and peak ejection rate (PER) were estimated. The global functions evaluated by this program were compared with those obtained by ERNA in the ERG. For regional assessment, the reference values of the functional indices were obtained for 17 LV segments in LPG. The Z score, (reference average value of the segment--patient's value of the segment)/reference standard deviation of the segment, was used for the evaluation of regional functions; a score equal to or greater than 2 was defined as abnormal. Semiquantitative visual interpretation of 2DE was used as the standard to assess wall motion. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of these criteria and the relationship between 2DE grading and Z scoring were validated in 2DEG.

RESULTS

The values of the global EF and PER evaluated by this program correlated with those determined by ERNA (r = 0.76 and 0.58, respectively; p < 0.005 and 0.01, respectively). The sensitivities of regional EF and PER for segmental wall motion abnormalities were 86.7% and 68.7%, respectively; their specificities were 86.7% and 95.5%, respectively; their PPVs were 64.3% and 79.2%, respectively; and their NPVs were 96.0% and 91.7%, respectively. The Z scores of these indices significantly correlated with the scores determined by 2DE (rs = 0.70 and 0.68, respectively; p < 10(-10)).

CONCLUSION

The potential of this program to quantify the regional systolic function was validated.

Evaluation of the Quantitative Gated SPECT (QGS) software program in the presence of large perfusion defects

OBJECTIVES

To evaluate the reproducibility and operator dependence for the quantitative regional left ventricular functional parameters (LVFP) assessed by Cedars-Sinai's Quantitative automated gated SPECT (QGS) software.

METHODS

The QGS algorithm was reviewed in detail and potential operator dependencies were defined. Series of prototypes were selected, consisting of (a) normal perfusion, (b) perfusion defects in all perfusion regions, (c) perfusion studies of patients with angiographic confirmed normal coronary arteries, proximal (>or=70% stenoses) single and multiple vessel disease, and (d) spurious activity in close proximity. While defining and re-orienting the volume containing the left ventricle, the operator adjusted 8 variables/degrees of freedom (DF). The software was used without further operator interventions. Results were expressed as a coefficient of variation (COV). Separate COV were calculated per distinct DF. A segment was considered not robust when the COV did exceed 20% in a single DF, 15% in at least 2 DF, or 10% in at least 3 DF.

RESULTS

Regional left ventricular EF and volumes showed excellent reproducibility. Normal perfusion and the vessel disease prototypes showed an excellent COV (for all re-orientation steps [33/prototype]) mostly below 5% for LVFP. However, regional wall motion and thickening became less reliable in the presence of large perfusion defects or artifacts.

CONCLUSIONS

Quantitative estimates for regional left ventricular functional data show excellent reproducibility using automated gated SPECT. However, there may be substantial operator dependency in the presence of large defects or spurious activity in close proximity.

Decreased septal wall thickening in patients with left bundle branch block

OBJECTIVES

Septal wall motion abnormalities are frequently observed in patients with left bundle branch block (LBBB). However, septal wall thickening in LBBB patients has not been thoroughly evaluated.

METHODS AND RESULTS

To investigate the relationship between septal wall motion and wall thickening, we studied 31 normal control subjects, 24 LBBB patients with normal wall motion (LBBB-NWM), and 24 LBBB patients with septal dyssynchrony (LBBB-SDS), all with a low likelihood (<15%) of coronary artery disease. The septal and lateral quadrants of the left ventricle were analyzed in stress 8-frame gated technetium 99m sestamibi tomograms. The percent wall thickening was calculated by use of a 25-segment polar map with the p-FAST software program by two independent methods: the regional count density increase from end diastole to end systole (CD method) and the geometric increase in the distance between the 50% thresholded endocardial and epicardial borders from end diastole to end systole (GD method). In addition, the ratio of septal/lateral percent wall thickening was calculated. The relative septal wall thickening in the entire LBBB population was decreased as compared with the normal control subjects (0.35 +/- 0.37 vs 0.81 +/- 0.17, P <.001). Decreased wall thickening was observed in not only LBBB-SDS patients but also to a lesser degree in LBBB-NWM patients (0.12 +/- 0.35, P <.001; 0.57 +/- 0.24, P =.005, respectively). This abnormality was most apparent when the CD method was used.

CONCLUSIONS

Septal wall thickening is decreased in patients with LBBB even with normal wall motion. LBBB per se may compromise septal wall thickening, and dyssynchronous wall motion results in further deterioration of wall thickening.