定量门控99Tcm-MIBI/201Tl心肌显像左心室射血分数正常参考值的建立

目的：应用定量门控^99Tc^m－甲氧基异丁基异腈（MIBI）和^201T1心肌显像测量静息左心室射血分数（LVEF），建立其正常参考值。方法；对277例患冠心病（CAD）低风险概率（＜10％）受检者行运动负荷－静息门控心肌断层显像。受检者分^99Tc^m－MIBI组（110例）和^201T1组（167例），各组再分无高血压（HBP）亚组（^99Tc^m－MIBI组85例，^201T1组128例）和HBP不伴左室肥厚9LVH）亚组（^99Tc^m－MIBI组25例，^201T1组39例）。采用QGSPECT专用分析程序测量静息LVEF。结果：^99Tc^m－MIBI组和^201T1组中HBP亚组的静息LVEF值均明显高于无HBP亚组（P均＜0．05），无HBP男性患者的静息LVEF值明显低于女性患者（P＜0．01）；无HBP者的心率、年龄与静息LVEF值间无线性相关（P均＞0．05）。^99Tc^m－MIBI组和^201T1组静息LVEF值均呈正态分布，其静息LVEF正常参考值分别为≥45％和≥43％。考虑性别影响，则^99Tc^m－MIBI组男性≥45％，女性≥48％；^201T1组男性≥42％，女性≥47％。结论：LVEF正常参考值有潜在的临床价值。     

99 Tcm-MIBI门控心肌显像ECTS软件测量左室射血分数

目的评价99Tcm-甲氧基异丁基异腈(MIBI)门控心肌显像Emory Cardiac Toolbox softwere (ECTS)处理软件测量左室射血分数(LVEF)的临床价值.方法 31例受检者,采用静息-多巴酚丁胺负荷一日法,行99Tcm-MIBI门控心肌断层显像,用ECTS软件测量LVEF,并于1周内完成平衡法心室显像,比较2种方法测量LVEF的相关性及一致性.结果①ECTS软件分析左室功能参数的重复性很好,变异系数(CV)均小于2%.②99Tcm-MIBI门控心肌显像ECTS软件测定LVEF值与平衡法心室显像测定值相关性良好(r=0.893,P<0.001).③ECTS软件测定的LVEF值[(57.3±2.93)%]较心室显像测定值[(46.6±2.86)%]高(t=7.76,P<0.001).结论 99Tcm-MIBI门控心肌显像ECTS软件与平衡法心室显像测定LVEF值具有较好的相关性,但前者测量值较后者高.99Tcm-MIBI门控心肌显像ECTS软件测定LVEF值能否完全取代平衡法心室显像测定,尚需进一步研究.     

Repeatability of automatic left ventricular cavity volume measurements from myocardial perfusion SPECT

Background

This study sought to assess the repeatability of automatic quantitative measurements of left ventricular (LV) cavity volumes in a large patient population (N=926), to correlate those measurements to similarly obtained LV ejection fraction (LVEF) measurements, and to investigate the relationship between ungated and gated volumes.

Methods

All 926 patients underwent ungated single photon emission computed tomography (SPECT) immediately followed by 8-frame gated SPECT. LV cavity volumes were automatically measured from ungated (V), summed gated (SUMV), end-systolic (ESV) and end-diastolic (EDV) images, and LVEFs derived from the latter 2.

Results

Repeatability (SUMV vs V) was very good overall (6.4%±6.6%), further improving for volumes >25 mL (5.7%±5.5%) and >40 mL (5.2%±5.0%). Exponential regression between ESV and LVEF (r=0.925, SEE=15.0 mL) EDV and LVEF (r=0.802, SEE=24.2 mL), and SUMV and LVEF (r=0.867, SEE=19.7 mL) was also very good. Summed gated volumes were closer to ESV than to EDV (43.3%±8.8% of EDV-ESV range). SUMV <50 mL and SUMV >110 mL were good substitutes for LVEF >50% and LVEF <40% (93.4% and 97.1%, respectively).

Conclusion

Automatic quantitative measurements of gated and ungated volumes with our algorithm are repeatable, correlate well with other global myocardial parameters, and may contribute important additional information to that conventionally provided by myocardial perfusion SPECT studies.     

Clinical application of left ventricular volume and ejection fraction derived from gated SPECT data

Left ventricular (LV) volume and ejection fraction (LVEF) derived from ECG-gated myocardial SPECT data are reproducible and objective. Those quantitative values, however, interacted according to varied factors such as a frame number per R-R interval, tracers, and processing-algorisms. A decrease of frame number per R-R interval yields underestimation of end-diastolic volume and overestimation of end-systolic volume, resulting in underestimation of LVEF. Thus, it is important to change a frame number per R-R interval by the examination purpose. A good correlation of LVEF is usually obtained, independent of a combination of tracer and processing-algorism. On the other hand, LV volume does not always show linearity between combinations of tracer and processing-algorism. An extraction of myocardial edge using QGS program is deteriorating in patients with small LV below 20 ml. It is crucial to assess LV functional values derived from ECG-gated SPECT data as clinical indices, taking the varied effects into consideration.     

Prognostic value of poststress left ventricular volume and ejection fraction by gated myocardial perfusion SPECT in women and men: Gender-related differences in normal limits and outcomes

Background  Whether there are gender differences in the prognostic application of gated myocardial perfusion single photon emission computed tomography (SPECT) has not been assessed. asMethods and Results Gender-specific normal limits of poststress volume and ejection fraction (EF) were obtained in 597 women and 824 men with a low likelihood of coronary artery disease and normal perfusion and were applied in a prognostic evaluation of 6713 patients (2735 women and 3978 men). Patients underwent rest thallium-201/stress technetium-99m sestamibi gated myocardial perfusion SPECT and were followed up for 35 ± 14 months. The upper limit of the end-systolic volume (ESV) index was 27 mL/m2 in women and 39 mL/m2 in men, and the upper limit of the end-diastolic volume index was 60 mL/m2 in women and 75 mL/m2 in men. The lower limit of the EF was 51% in women and 43% in men. Gated SPECT variables provided incremental prognostic information in both genders. Women with severe ischemia and an EF lower than 51% or an ESV index greater than 27 mL/m2 were at very high risk of cardiac death or myocardial infarction (3-year event rates of 39.8% and 35.1%, respectively), whereas women with severe ischemia but an EF of 51% or greater or an ESV index of 27 mL/m2 or less were at intermediate or high risk (3-year event rates of 10.8% and 15.2%, respectively). Conclusion  Poststress EF and ESV index by gated myocardial perfusion SPECT provide comparable incremental prognostic information over perfusion in women and men. After separate criteria for abnormal EF and ESV index in women are used, the combination of severe ischemia and abnormal EF or ESV index identifies women at very high risk of cardiac events. Partial funding was provided by grants from Bristol-Myers Squibb Medical Imaging, Inc, Billerica, Mass, and Astellas Pharma US, Inc, Deerfield, Ill.     

Reproducibility of left ventricular volume and ejection fraction measurements in rat using pinhole gated SPECT

Purpose The aim of this study was to investigate the intra-individual reproducibility of left ventricular volume and ejection fraction measurements in living rat using pinhole gated single-photon emission computed tomography (SPECT).Methods Eight normal male Wistar rats underwent four pinhole gated SPECT acquisitions over a 1-month period. Two pinhole gated myocardial perfusion SPECT studies were acquired at a 1-week interval after injecting the animals with 439±52 MBq of ^99mTc-sestamibi. Subsequently, 1 week after the perfusion studies, two pinhole gated blood pool SPECT studies were acquired at a 1-week interval after in vivo labelling of the red blood cells using 520±49 MBq of ^99mTc-pertechnetate. Pinhole gated SPECT acquisitions were done on a single-head gamma camera equipped with a pinhole collimator with a 3-mm opening and 165-mm focal length. Parameters of acquisition were as follows: 44 mm radius of rotation, 360° rotation using a circular orbit, 64 projections, 64×64 matrix, gating using 16 time frames and 22-min acquisition time. The projection data were reconstructed with a modified version of OSEM taking into account the pinhole geometry and incorporating a prior assumption about the temporal properties of gated SPECT studies to reduce noise. Left ventricular volumes and ejection fraction were measured using automatic quantification algorithms. Inter-study, inter-observer and intra-observer reproducibility was investigated.Results Pinhole gated myocardial perfusion and pinhole gated blood pool images were of high quality in all animals. No significant differences were observed between the repeated measurements. The pinhole gated myocardial perfusion SPECT studies indicated that differences between repeated measurements larger than 41 l for end-diastolic volume, 17 l for end-systolic volume and 3% for ejection fraction were significant. The pinhole gated blood pool SPECT studies indicated that differences between repeated measurements larger than 42 l for end-diastolic volume, 38 l for end-systolic volume and 5% for ejection fraction were significant. In addition to the reproducibility measures, the accuracy of volume measurements in pinhole gated blood pool SPECT was confirmed by a phantom study. Excellent correlations were observed between the measured volumes and the actual phantom volumes.Conclusion Pinhole gated SPECT is an accurate and reproducible technique for cardiac studies of small animals. Because this technique is non-invasive, the same animal can be imaged repetitively, allowing follow-up studies.     

Left ventricular volumes and ejection fraction calculated from quantitative electrocardiographic-gated 99mTc-tetrofosmin myocardial SPECT.

We compared the left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (LVEF) as calculated by Cedars automated quantitative gated SPECT (QGS) to those determined by first-pass radionuclide angiography (FPRNA) and contrast left ventriculography (LVG) in a group of 21 patients (mean age 61.4 +/- 9.2 y). METHODS: A total of 740 MBq 99mTc-tetrofosmin was administered rapidly into the right cubital vein at rest, and FPRNA was performed using a multicrystal gamma camera. One hour after injection, QGS was performed with a temporal resolution of 10 frames per R-R interval. LVG was performed within 2 wk. RESULTS: The EDV, ESV and LVEF calculated by QGS were highly reproducible (intraobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; interobserver, r = 0.99, r = 0.99 and r = 0.99, respectively; P < 0.01) and were more consistent than those determined by FPRNA (intraobserver, r = 0.97, r = 0.95 and r = 0.93, respectively; interobserver, r = 0.86, r = 0.96 and r = 0.91, respectively; P < 0.01). There was a good correlation between EDV, ESV and LVEF by FPRNA and those by LVG (r = 0.61, r = 0.72 and r = 0.91, respectively; P < 0.01), and there was an excellent correlation between QGS and LVG (r = 0.73, r = 0.83 and r = 0.87, respectively; P < 0.01). The mean EDV by QGS (100 +/- 11.3 mL) was significantly lower than by FPRNA (132 +/- 16.8 mL) or LVG (130 +/- 8.1 mL), and the mean ESV by QGS (53.8 +/- 9.3 mL) was lower than by FPRNA (73.0 +/- 13.3 mL). Ejection fraction values were highest by LVG (57.1% +/- 3.2%), then QGS (51.8% +/- 3.0%) and FPRNA (48.9% +/- 2.4%). CONCLUSION: QGS gave more reproducible results than FPRNA. LV volumes and LVEF calculated by QGS correlated well to those by LVG.     

Evaluation of left ventricular volumes and ejection fraction by gated myocardial perfusion SPECT versus cardiac MRI

It is stated that cardiac MRI imaging can provide accurate estimation of left ventricular (LV) volumes and ejection fraction (EF). The purpose of this study was to evaluate the accuracy of gated myocardial perfusion SPECT for assessment of LV end-diastolic volume (EDV), end-systolic volume (ESV) and EF, using cardiac MRI as the reference methods/(methodology). Gated myocardial perfusion SPECT images were analyzed with two different quantification software, QGS and 4D-MSPECT. Thirty-four consecutive patients were studied. Myocardial perfusion SPECT and cardiac MRI had excellent intra/interobserver reproducibility. Correlation between the results of gated myocardial perfusion SPECT and cardiac MRI were high for EDV and EF. However, ESV and EDV were significantly underestimated by gated myocardial perfusion SPECT compared to cardiac MRI. Moreover, gated myocardial perfusion SPECT overestimated EF for small heart. One reason for the difference in volumes and EF is the delineation of the endocardial border. Cardiac MRI has higher spatial resolution. We should understand the differences of volumes and EF as determined by gated myocardial perfusion SPECT and cardiac MRI.     

Correlation of right and left ventricular ejection fraction and volume measurements

First-pass radiocardiography and biplane angiocardiography were performed on 13 patients with left-sided regurgitant valvular disease (R+) and 7 patients without regurgitation but with coronary artery disease and/or cardiomyopathy (R-). Right and left ventricular volumes and ejection fractions were calculated and compared. In the R- group, corresponding right and left ventricular volumes and ejection fractions correlated highly with each other (r = 0.86-0.89, p approximately equal to 0.01). Ejection fractions in the R+ group correlated (r = 0.64, p less than 0.05) only because stroke volume correlation was very high (r = 0.93), with end-diastolic and end-systolic volumes showing no significant correlation. Right ventricular ejection fraction (RVEF) decreased significantly with increasing mean pulmonary artery pressure (PAP) in both R- and R+ groups. The correlation of RVEF and LVEF in the R- group appears to be multifactorial in origin, consisting of effects of increased PAP, the mechanical interference of an enlarged left ventricle on the right ventricle, and direct biventricular ischemic effects. In the R+ group, the correlation appears to be due to only increased PAP and its sequelae.     

Comparison of automatic quantification software for the measurement of ventricular volume and ejection fraction in gated myocardial perfusion SPECT

The aim of this study was to compare the performance of three different software packages for the calculation of ejection fraction (EF) and end diastolic volume (EDV) from gated myocardial single photon emission computed tomography studies. Two hundred patients undergoing gated stress myocardial perfusion scans were analysed retrospectively. Patients were grouped as follows: small heart (n=31), normal perfusion scan (n=71), and scan with perfusion defects (n=98). EF and EDV were calculated for each using QGS (Cedars Sinai, Los Angeles, CA), 4D-MSPECT (University of Michigan, Ann Arbor, MI), and ECT (Emory University, Atlanta, GA). Bland-Altman plots, repeated measures ANOVA, and linear regression analysis were used to compare methods. Correlation coefficients between the methods for both EF and EDV were high, greater than 0.9. However, Bland-Altman plots revealed a large standard deviation of the difference between methods, preventing the confident estimate of the value of one method from an observation of another. Despite good correlation, the variance between methods was high. These algorithms behave differently, produce widely variable results from one another, and should not be used interchangeably. It may prove prudent for laboratories to independently validate the software algorithm that is chosen against a 'gold standard' using their own population.     

Left ventricular ejection fraction and volumes calculated from dual gated SPECT myocardial imaging with 99Tcm-MIBI.

Dual gated (DG) cardiac single photon emission computed tomographic (SPECT) studies at end-diastole (ED) and end-systole (ES) were acquired in 27 ischaemic heart disease (IHD) patients after intravenous injection of 555-740 MBq 99Tcm-MIBI. Acquisition parameters were: 180 degrees from LPO to RAO, 32 projections, 64 x 64 matrix, 75 cardiac beats per projection, 80 ms at ED and 80 ms at ES for each cardiac cycle. A computer program was developed to calculate the ED and ES left ventricular (LV) volumes and LV ejection fraction (EF). The computational approach is interactive, semi-automatic and iterative with built-in visual quality control. Short axis slices are used with corresponding ED and ES slices processed as pairs from apex to base. Left ventricular cavity pixels are identified and summed on a slice-by-slice basis. Myocardial pixels are similarly identified. The computed LVEF and ED and ES volumes have been correlated with those from contrast ventriculography (CV). The mean calculated EF for 27 patients was 53.6 +/- 10.7% from DG SPECT versus 55.3 +/- 12.1% from CV (NS). The EF linear correlation coefficient was r = 0.97.     

Prone versus supine patient positioning during gated 99mTc-sestamibi SPECT: effect on left ventricular volumes, ejection fraction, and heart rate.

Gated myocardial perfusion SPECT allows assessment of left ventricular end-diastolic volume (EDV), left ventricular end-systolic volume (ESV), left ventricular stroke volume (SV), and left ventricular ejection fraction (LVEF). Acquiring images with the patient both prone and supine is an approved method of identifying and reducing artifacts. Yet prone positioning alters physiologic conditions. This study investigated how prone versus supine patient positioning during gated SPECT affects EDV, ESV, SV, LVEF, and heart rate. METHODS: Forty-eight patients scheduled for routine myocardial perfusion imaging were examined with gated (99m)Tc-sestamibi SPECT (at rest) while positioned prone and supine (consecutively, in random order). All parameters for both acquisitions were calculated using the commercially available QGS algorithm. RESULTS: Whereas EDV and SV were significantly lower (P < 0.0004) for prone acquisitions (EDV, 110.5 +/- 39.1 mL; SV, 55.9 +/- 13.3 mL) than for supine acquisitions (EDV, 116.9 +/- 36.2 mL; SV, 61.0 +/- 14.5 mL), ESV and LVEF did not differ significantly. Heart rate was significantly higher (P < 0.0001) during prone acquisitions (69.1 +/- 10.5 min(-1)) than during supine acquisitions (66.5 +/- 10.0 min(-1)). CONCLUSION: The observed position-dependent effect on EDV, SV, and heart rate might be explained by decreased arterial filling and increased sympathetic nerve activity. Hence, supine reference data should not be used to classify the results of prone acquisitions.     

Measurement of left ventricular ejection fraction from gated technetium-99m sestamibi myocardial images

Left ventricular ejection fraction (LVEF) and single-photon emission tomographic (SPET) imaging of the myocardium can be performed after a single technetium-99m sestamibi (MIBI) injection. Sixty patients underwent SPET imaging with MIBI. Immediately after SPET acquisition ECG-gated^99mTc-MIBI perfusion images were acquired using 24 planar images per R-R interval. A new method for measurement of LVEF from the ECG-gated 99mTc-MIBI perfusion images was developed. To validate the method, LVEF derived from MIBI perfusion images was compared with that from conventional radionuclide ventriculography in all 60 patients. Forty patients had evidence of myocardial infarction and 20 had normal perfusion on MIBI imaging. There was no statistically significant difference between LVEF computed from^99mTc-MIBI perfusion images and that from radionuclide ventriculography (r=0.7062,P<0.001). There was little difference associated with the technique (intraobserver variabilityr=0.9772,P<0.001). Interobserver variability was also good (r-0.8233,P<0.001). LVEF from^99mTc-MIBI perfusion images can be obtained at the same time as assessment of myocardial perfusion and in the same orientation and metabolism of the myocardium, thereby permitting more accurate and realistic prognosis and diagnosis in patients with coronary artery disease.     

Assessment of diastolic function using 16-frame 99mTc-sestamibi gated myocardial perfusion SPECT: normal values.

The purposes of this study were (a) to assess the feasibility of diastolic function (DFx) evaluation using standard 16-frame postexercise gated (99m)Tc-sestamibi myocardial perfusion SPECT (MPS), (b) to determine the relationship of the 2 common DFx parameters, peak filling rate (PFR) and time to peak filling (TTPF), to clinical and systolic function (SFx) variables in patients with normal myocardial perfusion and SFx, and (c) to derive and validate normal limits. METHODS: Ninety patients (71 men; age, 30-79 y) with normal exercise gated MPS were studied. None had hypertension, diabetes, rest electrocardiogram abnormality, or known cardiac disease. All patients reached > or = 85% of maximum predicted heart rate (HR). The population was randomized into derivation (n = 50) and validation (n = 40) groups. Univariable and multivariable approaches were deployed to assess the influence of clinical and functional variables on DFx parameters. RESULTS: PFR and TTPF were assessed in all patients. Mean values of PFR and TTPF in the whole study population were 2.62 +/- 0.46 end-diastolic volumes per second (EDV/s) and 164.6 +/- 21.7 ms, respectively. By applying a 2-SD cutoff to the mean values in the derivation group, the threshold for abnormal PFR and the threshold for abnormal TTPF were < 1.71 EDV/s and > 216.7 ms, respectively. The normalcy rates in the validation group for PFR and TTPF were both 100%. The PFR showed weak but significant correlations with age, EDV, end-systolic volume, left ventricular ejection fraction (LVEF), and poststress HR. However, TTPF did not correlate with these parameters. Final normal thresholds determined from the combined populations were PFR = 1.70 EDV/s and TTPF = 208 ms. Multivariable analysis showed that age, sex, LVEF, and HR are strong predictors for PFR, whereas TTPF was not influenced by any clinical or SFx variable. CONCLUSION: With a new algorithm in QGS, assessment of LV DFx is feasible using 16-frame gated MPS even without bad-beat rejection, resulting in normal limits similar to those reported with gated blood-pool studies. However, due to the dependency of PFR on SFx parameters, sex, HR, and age, TTPF appears to be a stable and more useful parameter with this approach. The clinical usefulness of these findings requires further study.     

Repeatability of left ventricular ejection fraction and volume measurement for 99mTc-tetrofosmin gated single photon emission computed tomography (SPECT)

OBJECTIVES: This study was carried out to assess the repeatability of left ventricular ejection fraction (EF) and volume values obtained using Cedars-Sinai quantitative gated single photon emission computed tomography (SPECT) (QGS) software and relatively low doses of 400-600 MBq of 99mTc-tetrofosmin. METHODS: Repeatability was assessed in a group of 75 patients, with both normal and reduced EF, who underwent repeat 99mTc-tetrofosmin gated SPECT studies and showed no clinical change in cardiac status. Gated SPECT data were acquired 1 h after injection at rest of 400-600 MBq of 99mTc-tetrofosmin. The standard patient dose was 400 MBq; however, some patients with a weight of >90 kg were given increased doses up to a maximum of 600 MBq. RESULTS: There was good correlation of EF and volumes between the first and repeat measurements, and no significant difference between the mean EF and volumes for both the initial and repeat measurements. Background-corrected counts in the left ventricle were calculated and patients were divided into two groups: one with low counts and one with high counts. The mean difference in EF between the first and repeat measurements was significantly higher for patients in the low count group compared with those in the high count group, but there was no significant change in volume. Similarly, the mean sequential difference in EF was significantly higher for patients with normal EF, but there was no significant difference in volume. CONCLUSIONS: We have demonstrated that EF measured using 99mTc-tetrofosmin gated SPECT is repeatable, particularly for patients with low EF, provided that adequate left ventricular counts are obtained. This will require doses greater than 400 MBq in larger patients. Ventricular volumes calculated using QGS may not be sufficiently repeatable for clinical use.     

Effect of sex, age, and weight on ejection fraction and end-systolic volume reference limits in gated myocardial perfusion SPECT

Background  The left-ventricular ejection fraction (EF) and end-systolic volume (ESV) are strong predictors of prognosis for cardiac death. Gated myocardial perfusion single-photon emission computed tomography (gSPECT) may be used to measure ESV and EF. However, systematic differences may exist between referred populations. Our aim was to derive male and female reference limits for left-ventricular functional parameters, and determine the effect of age, weight, and body surface area (BSA). Methods and Results  The ejection fraction and ESV were derived using QGS software for 127 patients with normal gSPECT studies. The lower reference limits of EF were 46.2% and 55.6% for men and women, respectively. The upper reference limits of ESV were 30.4 mL and 21.4 mL, and 15.7 mL/m² and 11.1 mL/m², when indexed to BSA for men and women, respectively. There was no correlation between EF and age, weight, or BSA (P>.05). There was a small decrease in ESV with age, and an increase with weight and BSA (P<.05). The sex-specific differences remained after adjusting for confounding variables. Conclusions  We demonstrated a significant sex difference for all functional parameters measured, and we established the influence of patient age and weight. Local reference limits for ESV and EF have been established, and the latter are transferable to other departments operating similar protocols.     

Quantitation of left ventricular ejection fraction reserve from early gated regadenoson stress Tc-99m high-efficiency SPECT

Background

Ejection fraction (EF) reserve has been found to be a useful adjunct for identifying high risk coronary artery disease in cardiac positron emission tomography (PET). We aimed to evaluate EF reserve obtained from technetium-99m sestamibi (Tc-99m) high-efficiency (HE) SPECT.

Methods

Fifty patients (mean age 69 years) undergoing regadenoson same-day rest (8-11 mCi)/stress (32-42 mCi) Tc-99m gated HE SPECT were enrolled. Stress imaging was started 1 minute after sequential intravenous regadenoson .4 mg and Tc-99m injections, and was composed of five 2 minutes supine gated acquisitions followed by two 4 minutes supine and upright images. Ischemic total perfusion deficit (ITPD) ≥5 % was considered as significant ischemia.

Results

Significantly lower mean EF reserve was obtained in the 5th and 9th minute after regadenoson bolus in patients with significant ischemia vs patients without (5th minute: ?4.2 ± 4.6% vs 1.3 ± 6.6%, P = .006; 9th minute: ?2.7 ± 4.8% vs 2.0 ± 6.6%, P = .03).

Conclusions

Negative EF reserve obtained between 5th and 9th minutes of regadenoson stress demonstrated best concordance with significant ischemia and may be a promising tool for detection of transient ischemic functional changes with Tc-99m HE-SPECT.

     

Automatic quantification of left ventricular ejection fraction from gated blood pool SPECT

BACKGROUND: Cardiac gated blood pool single photon emission computed tomography (GBPS) better separates cardiac chambers compared with planar radionuclide ventriculography (PRNV). We have developed a completely automatic algorithm to measure quantitatively the left ventricular ejection fraction (LVEF) from gated technetium 99m-red blood cells (RBC) GBPS short-axis 3-dimensional image volumes. METHODS AND RESULTS: The algorithm determines an ellipsoidal coordinate system for the left ventricle and then computes a static estimate of the endocardial surface by use of counts and count gradients. A dynamic surface representing the endocardium is computed for each interval of the cardiac cycle by use of additional information from the temporal Fourier transform of the image data sets. The algorithm then calculates the left ventricular volume for each interval and computes LVEF from the end-diastolic and end-systolic volumes. The algorithm was developed in a pilot group (N = 45) and validated in a second group (N = 89) of patients who underwent PRNV and 8-interval GBPS. Technically inadequate studies (N = 38) were rejected before grouping and processing. Automatic identification and contouring of the left ventricle was successful in 121/172 patients (70%) globally and in 76/89 patients (85 %) in the validation group. Correlation between LVEFs measured from GBPS and PRNV was high (y = 2.00 + 1.01x, r = 0.89), with GBPS LVEF significantly higher than PRNV LVEF (average difference = 2.8%, P < .004). CONCLUSIONS: Our automatic algorithm agrees with conventional radionuclide measurements of LVEF and provides the basis for 3-dimensional analysis of wall motion.     

Comparison of dobutamine echocardiography and 99mTc-sestamibi tomography for prediction of left ventricular ejection fraction outcome after acute myocardial infarction treated with successful primary coronary angioplasty.

For patients with acute myocardial infarction who undergo primary percutaneous transluminal coronary angioplasty (PTCA), it is important to promptly identify those in whom a significant delayed improvement of global left ventricular function is to be expected as a result of successful treatment. METHODS: In 51 patients with acute myocardial infarction who underwent primary PTCA with a good angiographic result, the late outcome of the left ventricular ejection fraction (LVEF) was established after a 6-mo follow-up. In the early phase after infarction (within approximately 1 wk of infarction), the contractile reserve of the infarct zone was evaluated using dobutamine echocardiography and compared with the assessment of infarct size, infarct severity, and mean tracer activity of the infarct zone obtained using resting 99mTc-sestamibi SPECT. Receiver-operating-curve (ROC) analysis was used to define the reliability of the various parameters for identifying the patients with a follow-up LVEF increase of > or = 5 LVEF units. RESULTS: Of the 48 patients without restenosis at follow-up, 34 showed significant LVEF improvement. The evaluation of the contractile reserve of the infarct zone achieved an ROC curve area of 0.75 +/- 0.07 with 74% sensitivity, 71% specificity, and 73% overall accuracy. Of the 99mTc-sestamibi SPECT parameters, the extent of the infarct had no diagnostic value according to ROC analysis. The mean activity of the infarct zone had an ROC curve area of 0.64 +/- 0.09 with 82% sensitivity, 50% specificity, and 73% overall accuracy. The infarct severity had an ROC area of 0.76 +/- 0.08 (not significant vs. mean activity and vs. contractile reserve) with 77% sensitivity, 71% specificity, and 75% overall accuracy. CONCLUSION: Evaluation of the contractile reserve of the infarct zone using dobutamine echocardiography and assessment of the tracer activity of the infarct zone or infarct severity using 99mTc-sestamibi SPECT in the early phase after infarction are able to identify the patients in whom successful primary PTCA will be followed by significant late LVEF improvement.     

定量门控99Tcm-tetrofosmin心肌显像测量左室功能

目的探讨定量门控(QG)99Tcm-tetrofosmin心肌显像测量左室功能的临床应用价值.方法74例受试者进行了门控99Tcm-tetrofosmin心肌显像,采用QGSPECT专用分析程序全自动测量左室功能.其中36例同时进行静息门控心室显像,以比较两种方法测量左室功能的相关性.结果①74例99Tcm-tetrofosminQGSPECT全自动定量测定左室功能均获成功.②QGSPECT全自动测量36例受试者的静息左室射血分数(LVEF)、舒张末期容积(EDV)、收缩末期容积(ESV)分别与静息门控心室显像计算结果显著正相关(r分别为0.859,0.914,0.950,P均<0.001),重复性好.③心肌缺血组(n=28)静息LVEF与对照组(n=23)比较差异无显著性,而心肌梗死组(n=9)静息LVEF明显低于对照组(t=6.33,P<0.001).结论定量门控心肌显像99Tcm-tetrofosmin能准确评价左室功能.