Evaluation of left and right ventricular ejection fraction and volumes from gated blood-pool SPECT in patients with dilated cardiomyopathy: comparison with cardiac MRI

Sixteen-Frame Gated Myocardial Perfusion SPECT as a Surrogate for Equilibrium Radionuclide Angiography in Measurement of Systolic and Diastolic Indices: A Cross-Sectional Study

Introduction  Equilibrium radionuclide angiography (ERNA) has long been assumed as the preferred method to assess cardiac volumes as well as left ventricular systolic and diastolic indices. ERNA was used to diagnose subtle changes in cardiac function during chemotherapy or early stages of heart failure. Gated myocardial perfusion SPECT (GMPS) was introduced as a more feasible and versatile alternative to ERNA, but the precision of GMPS to assess systolic and diastolic indices has not yet been fully reviewed. Method  We studied the left ventricular systolic and diastolic functional indices measured by a 16-frame GMPS and compared the results with those of ERNA in 25 patients. All the images were analyzed visually, semi-quantitatively, and quantitatively using quantitative gated SPECT (QGS), quantitative blood pool SPECT (QBS), and planar gated blood pool (PGBP) software. The left ventricular functional indices calculated using QGS compared with those obtained using QBS and PGBP Result  Our study found a significant correlation between the left ventricular ejection fraction (LVEF) calculated using the PGBP, QGS, and QBS methods. There was a significant correlation between the LV peak ejection rate (LVPER) calculated by the PGBP and QGS analyses, and there was no significant difference in the LVPER calculated with the QGS and QBS methods. This study also revealed a significant correlation between the LV peak filling rate (LVPFR) calculated by QBS and QGS, with no significant difference between them. We also found a significant correlation between LV end systolic volume (LVESV) calculated using QGS and QBS and between LV end diastolic volume (LVEDV) calculated using QGS and QBS software. This study also revealed a significant correlation between the LV mean filling rate over the first third of diastole (LVMFR/3) calculated using the QGS and QBS software. Conclusion  Considering the significant correlation between LVEF, LVPER, LVPFR, LVESV, LVMFR/3, and LVEDV calculated using the QGS and QBS methods in our study, the 16-frame GMPS could be regarded as an acceptable substitute for ERNA in the investigation of systolic and diastolic indices.

Evaluation of biventricular function by cadmium-zinc-telluride SPECT gated tomographic radionuclide angiography: Comparison to conventional SPECT

We compared and analyzed the consistency and repeatability of left and right ventricular ((LV/RV) functions obtained by gated-equilibrium radionuclide ventriculography (ERNV) with cadmium-zinc-telluride single-photon emission computed tomography (CZT-SPECT) and conventional SPECT (C-SPECT) with sodium iodide crystal detectors. Seventy-seven patients were included in the retrospective study. Both C-SPECT and CZT-SPECT imaging were performed on the same day. Correlations and differences in LV/RV ejection fraction (LVEF and RVEF), peak ejection rate (PER), and peak filling rate (PFR) were compared between the 2 models. Cardiac magnetic resonance (CMR) was partially used as the gold standard, and ultrasound results were included for comparative analysis. Interobserver reproducibility of each parameter obtained by the 2 cameras was compared. Between the 2 cameras, there were no significant difference in LVEF, LVPER, LVPFR, and RVPER (P > .05) and there were in RVEF and RVPFR (P < .05 or .001). The correlations (R value) were 0.831 (LVEF, excellent), 0.619 (RVEF, good), 0.672 (LVPER, good), 0.700 (LVPFR, good), 0.463 (RVPER, normal), and 0.253 (RVPFR, poor). There were no significant difference between CMR and CZT-SPECT in LVEF (P > .05) while there were between CMR and both C-SPECT and ultrasound (P < .05). The correlations were all good (R = 0.660, 0.658, and 0.695). There were no significant difference between CMR and both C-SPECT and CZT-SPET in RVEF (P > .05) and the correlations were good (R = 0.771 and 0.745). For repeatability, the intraclass correlation coefficient of RVPFR by C-SPECT was good (intraclass correlation coefficient = 0.698) and excellent for the rest of the groups (0.823-0.989). The repeatability of LVEF and RVEF was better for CZT-SPECT than for C-SPECT. The repeatability of PER was better for both cameras than PFR. CZT-SPECT tomographic ERNV correlated well with C-SPECT planar ERNV in evaluation of biventricular systolic function and LV diastolic function. Compared with the "gold standard" CMR, both models had good correlation in measuring LV/RVEF. CZT-SPECT had better inter-group reproducibility than C-SPECT. The accuracy of RV diastolic function need further study. CZT-SPECT tomographic ERNV will play an important and unique role in the clinical application of accurate evaluation of biventricular function in the future.

Multimodality Imaging in Advanced Heart Failure for Diagnosis, Management and Follow-Up: A Comprehensive Review

Advanced heart failure (AHF) presents a complex landscape with challenges spanning diagnosis, management, and patient outcomes. In response, the integration of multimodality imaging techniques has emerged as a pivotal approach. This comprehensive review delves into the profound significance of these imaging strategies within AHF scenarios. Multimodality imaging, encompassing echocardiography, cardiac magnetic resonance imaging (CMR), nuclear imaging and cardiac computed tomography (CCT), stands as a cornerstone in the care of patients with both short- and long-term mechanical support devices. These techniques facilitate precise device selection, placement, and vigilant monitoring, ensuring patient safety and optimal device functionality. In the context of orthotopic cardiac transplant (OTC), the role of multimodality imaging remains indispensable. Echocardiography offers invaluable insights into allograft function and potential complications. Advanced methods, like speckle tracking echocardiography (STE), empower the detection of acute cell rejection. Nuclear imaging, CMR and CCT further enhance diagnostic precision, especially concerning allograft rejection and cardiac allograft vasculopathy. This comprehensive imaging approach goes beyond diagnosis, shaping treatment strategies and risk assessment. By harmonizing diverse imaging modalities, clinicians gain a panoramic understanding of each patient's unique condition, facilitating well-informed decisions. The aim is to highlight the novelty and unique aspects of recently published papers in the field. Thus, this review underscores the irreplaceable role of multimodality imaging in elevating patient outcomes, refining treatment precision, and propelling advancements in the evolving landscape of advanced heart failure management.

Tales from the future-nuclear cardio-oncology, from prediction to diagnosis and monitoring

Cancer and cardiovascular diseases (CVD) often share common risk factors, and patients with CVD who develop cancer are at high risk of experiencing major adverse cardiovascular events. Additionally, cancer treatment can induce short- and long-term adverse cardiovascular events. Given the improvement in oncological patients' prognosis, the burden in this vulnerable population is slowly shifting towards increased cardiovascular mortality. Consequently, the field of cardio-oncology is steadily expanding, prompting the need for new markers to stratify and monitor the cardiovascular risk in oncological patients before, during, and after the completion of treatment. Advanced non-invasive cardiac imaging has raised great interest in the early detection of CVD and cardiotoxicity in oncological patients. Nuclear medicine has long been a pivotal exam to robustly assess and monitor the cardiac function of patients undergoing potentially cardiotoxic chemotherapies. In addition, recent radiotracers have shown great interest in the early detection of cancer-treatment-related cardiotoxicity. In this review, we summarize the current and emerging nuclear cardiology tools that can help identify cardiotoxicity and assess the cardiovascular risk in patients undergoing cancer treatments and discuss the specific role of nuclear cardiology alongside other non-invasive imaging techniques.

Comparative Assessments of Left and Right Ventricular Function by Two-Dimensional, Contrast Enhanced and Three-Dimensional Echocardiography with Gated Heart Pool Scans in Patients Following Myocardial Infarction

Multiple noninvasive imaging modalities are available to measure biventricular function, although limited studies have assessed agreement between modalities in assessing left and right ventricular ejection fraction (LVEF & RVEF) in the same cohort of patients. In this study we prospectively compared the agreement of 2-dimensional echocardiography (2DE), contrast enhanced 2DE, 3-dimensional echocardiography (3DE), and gated heart pool scan (GHPS) measures of LVEF and RVEF in patients with acute ST-elevation myocardial infarction. We recruited 95 consecutive ST-elevation myocardial infarction patients (mean age 61.4 ± 12.0, male: 79.5%) admitted to a major tertiary hospital between July 2016 and May 2018. Despite minimal inter- and intra-observer variability (coefficient of variance < 5% in both categories), substantial discrepancies exist between modalities with Pearson's correlation coefficients ranging from 0.64 to 0.91 for LVEF measurements, and 0.27 to 0.86 for RVEF measurements. Bland-Altman plots demonstrated no systematic bias between modalities. GHPS and 3DE offered the closest agreement for both LVEF and RVEF, demonstrating the greatest correlation coefficient (r = 0.91 and 0.86 respectively), lowest mean absolute differences (4% and 3% respectively), and narrowest Bland-Altman limits of agreement (19% and 18% respectively). Greater than 10% of 2DE and contrast enhanced 2DE scans discordantly showed LVEF values >40% for patients whose LVEF was measured as ≤ 40% by 3DE or GHPS. In conclusion, substantial variation exists between modalities when assessing LVEF and RVEF, although we demonstrate that 3DE and GHPS have the closest agreement. This variability should be considered in clinical management of patients, and modalities should not be used interchangeably in sequential patient follow-up.

The role of cardiac imaging in the management of non-ischemic cardiovascular diseases in human immunodeficiency virus infection

Infection with human immunodeficiency virus (HIV) has become the pandemic of the new century. About 36.9 million people are living with HIV worldwide. The introduction of antiretroviral therapy in 1996 has dramatically changed the global landscape of HIV care, resulting in significantly improved survival and changing HIV to a chronic disease. With near-normal life expectancy, contemporary cardiac care faces multiple challenges of cardiovascular diseases, disorders specific to HIV/AIDS, and those related to aging and higher prevalence of traditional risk factors. Non-ischemic cardiovascular diseases are major components of cardiovascular morbidity and mortality in HIV/AIDS. Non-invasive cardiac imaging plays a pivotal role in the management of these diseases. This review summarizes the non-ischemic presentation of the HIV cardiovascular spectrum focusing on the role of cardiac imaging in the management of these disorders.

Assessment of left ventricular ejection fraction with cardiofocal collimators: Comparison between IQ-SPECT, planar equilibrium radionuclide angiography, and cardiac magnetic resonance

BACKGROUND

IQ-SPECT has been shown to significantly reduce acquisition time and administered dose while preserving image quality in myocardial perfusion imaging. Whether IQ-SPECT provides accurate left ventricular ejection fractions (LVEF) with gated blood pool SPECT (GBPS) remains unknown.

METHODS

Sixty patients underwent IQ-SPECT GBPS and planar imaging. Among those patients, 11 underwent both cMRI and GBPS. GBPS LVEF, LVEDV, and LVESV were calculated using 2 validated software; QBS (Cedars-Sinai Medical Center, Los Angeles, USA) and MHI (Montreal Heart Institute, Montreal, Canada). LVEF, LVEDV, and LVESV obtained with the different modalities were compared.

RESULTS

Average planar LVEF was 48 ± 11% (mean ± SD), average LVEDV was 177 ± 59 mL (range 63 to 342 mL), and average LVESV was 96 ± 46 mL (range 16 to 234 mL). GBPS LVEF and their correlation coefficient with planar LVEF were 40 ± 12% (r = 0.70) and 44 ± 12% (r = 0.83) with QBS and MHI, respectively. Correlation coefficient between cMRI and planar LVEF was 0.65 and were 0.69 and 0.52 between cMRI and GBPS using QBS and MHI, respectively.

CONCLUSIONS

LVEF calculated with GBPS using IQ-SPECT correlates with planar measurements. Correlation is best using the MHI method and variation is independent of LVEDV.

Left ventricular ejection fraction determined with the simulation of a very low-dose CZT-SPECT protocol and an additional count-calibration on planar radionuclide angiographic data

PURPOSE

To determine whether the left ventricular ejection fractions (EFs), measured on a high-sensitivity CZT single photon emission computed tomography (SPECT)-camera with a 70% reduction in recording times and a prevention of EF overestimation through an additional count-calibration, are concordant with reference EF from planar radionuclide angiography (2D-RNA).

METHODS

An additional 10-minute CZT-SPECT recording was performed in patients referred to 2D-RNA for cardiomyopathy (n = 23) or chemotherapy monitoring (n = 50) with an in vivo red blood cell labeling with 850 MBq [Formula: see text]. The EF, obtained from CZT-SPECT with 100% (SPECT100) or 30% (SPECT30) projection times and with a SPECT-count calibration on the 2D-RNA counts of corresponding cavity volumes, were compared to EF from 2D-RNA.

RESULTS

Strong and equivalent relationships were documented between the EF from 2D-RNA and the calibrated EF from SPECT100 (y = 0.89x + 6.62; R2 = 0.87) and SPECT30 (y = 0.87x + 8.40; R2 = 0.85), and the mean EF from SPECT100 (54% ± 15%) and SPECT30 (53% ± 16%) were close to that from 2D-RNA (55% ± 15%). However, upward shifts in these mean values were documented in the absence of count calibration for both SPECT100 (60% ± 18%) and SPECT30 (60% ± 18%).

CONCLUSION

Left ventricular EF may be determined on a high-sensitivity CZT-camera, a 70% reduction in injected activities, and an additional count-calibration for further enhancing the concordance with 2D-RNA values.

Variability in Ejection Fraction Measured By Echocardiography, Gated Single-Photon Emission Computed Tomography, and Cardiac Magnetic Resonance in Patients With Coronary Artery Disease and Left Ventricular Dysfunction

IMPORTANCE

Clinical decisions are frequently based on measurement of left ventricular ejection fraction (LVEF). Limited information exists regarding inconsistencies in LVEF measurements when determined by various imaging modalities and the potential impact of such variability.

OBJECTIVE

To determine the intermodality variability of LVEF measured by echocardiography, gated single-photon emission computed tomography (SPECT), and cardiovascular magnetic resonance (CMR) in patients with left ventricular dysfunction.

DESIGN, SETTING, AND PARTICIPANTS

International multicenter diagnostic study with LVEF imaging performed at 127 clinical sites in 26 countries from July 24, 2002, to May 5, 2007, and measured by core laboratories. Secondary study of clinical diagnostic measurements of LVEF in the Surgical Treatment for Ischemic Heart Failure (STICH), a randomized trial to identify the optimal treatment strategy for patients with LVEF of 35% or less and coronary artery disease. Data analysis was conducted from March 19, 2016, to May 29, 2018.

MAIN OUTCOMES AND MEASURES

At baseline, most patients had an echocardiogram and subsets of patients underwent SPECT and/or CMR. Left ventricular ejection fraction was measured by a core laboratory for each modality independent of the results of other modalities, and measurements were compared among imaging methods using correlation, Bland-Altman plots, and coverage probability methods. Association of LVEF by each method and death was assessed.

RESULTS

A total of 2032 patients (mean [SD] age, 60.9 [9.6] years; 1759 [86.6%] male) with baseline LVEF data were included. Correlation of LVEF between modalities was r = 0.601 (for biplane echocardiography and SPECT [n = 385]), r = 0.493 (for biplane echocardiography and CMR [n = 204]), and r = 0.660 (for CMR and SPECT [n = 134]). Bland-Altman plots showed only moderate agreement in LVEF measurements from all 3 core laboratories with no substantial overestimation or underestimation of LVEF by any modality. The percentage of observations that fell within a range of 5% ranged from 43% to 54% between different imaging modalities.

CONCLUSIONS AND RELEVANCE

In this international multicenter study of patients with coronary artery disease and reduced LVEF, there was substantial variation between modalities in LVEF determination by core laboratories. This variability should be considered in clinical management and trial design.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT00023595.

Cardiac MRI and radionuclide ventriculography for measurement of left ventricular ejection fraction in ICD candidates

OBJECTIVE

Current guidelines provide left ventricular ejection fraction (LVEF) criterion for use of implantable cardioverter defibrillators (ICD) but do not specify which modality to use for measurement. We compared LVEF measurements by radionuclide ventriculography (RNV) vs cardiac MRI (CMR) in ICD candidates to assess impact on clinical decision making.

METHODS

This single-centre study included 124 consecutive patients referred for assessment of ICD implantation who underwent RNV and CMR within 30 days for LVEF measurement. RNV and CMR were interpreted independently by experienced readers.

RESULTS

Among 124 patients (age 64 ± 11 years, 77% male), median interval between CMR and RNV was 1 day; mean LVEF was 32 ± 12% by CMR and 33 ± 11% by RNV (p = 0.60). LVEF by CMR and RNV showed good correlation, but Bland-Altman analysis showed relatively wide limits of agreement (-12.1 to 11.4). CMR LVEF reclassified 26 (21%) patients compared to RNV LVEF (kappa = 0.58). LVEF by both modalities showed good interobserver reproducibility (ICC 0.96 and 0.94, respectively) (limits of agreement -7.27 to 5.75 and -8.63 to 6.34, respectively).

CONCLUSION

Although LVEF measurements by CMR and RNV show moderate agreement, there is frequent reclassification of patients for ICD placement based on LVEF between these modalities. Future studies should determine if a particular imaging modality for LVEF measurement may enhance ICD decision making and treatment benefit.

Automated synthesis of [68Ga]oxine, improved preparation of 68Ga-labeled erythrocytes for blood-pool imaging, and preclinical evaluation in rodents

Radiolabeled erythrocytes have multiple applications in nuclear medicine, including blood pool imaging. Historically they have been labeled with SPECT radionuclides. A PET blood pool imaging agent is highly desirable as it would improve clinical applications with better image quality and resolution, higher sensitivity, and dynamic scanning capabilities. With the coming of age of modern 68Ge/68Ga generator systems, gallium-68 is now widely accessible. In this paper we describe an updated method for the preparation of 68Ga-labeled erythrocytes and their preliminary use in rodent blood pool imaging. A novel automated synthesis of [68Ga]oxine using a 68Ga/68Ge generator and automated synthesis module is reported. [68Ga]Oxine was synthesized in 50 ± 5% (n = 3) non-decay corrected radiochemical yield and >99% radiochemical purity. Rat and human erythrocytes were successfully labeled with the complex in 42% RCY, and the 68Ga-labeled erythrocytes have been shown to clearly image the blood pool in a healthy rat. Human erythrocytes labelled with [68Ga]oxine were shown to be viable up to 2 hours post-labelling, and washout of the radiolabel was minimal up to 1 hour post-labelling. Further optimization of the labeling method to translate for use in human cardiac and oncologic blood pool PET imaging studies, is underway.

18F-FDG-labeled red blood cell PET for blood-pool imaging: preclinical evaluation in rats

Background

Red blood cells (RBCs) labeled with single-photon emitters have been clinically used for blood-pool imaging. Although some PET tracers have been introduced for blood-pool imaging, they have not yet been widely used. The present study investigated the feasibility of labeling RBCs with ¹⁸F-2-deoxy-2-fluoro-D-glucose (¹⁸F-FDG) for blood-pool imaging with PET.

RBCs isolated from venous blood of rats were washed with glucose-free phosphate-buffered saline and labeled with ¹⁸F-FDG. To optimize labeling efficiency, the effects of glucose deprivation time and incubation (labeling) time with ¹⁸F-FDG were investigated. Post-labeling stability was assessed by calculating the release fraction of radioactivity and identifying the chemical forms of ¹⁸F in the released and intracellular components of ¹⁸F-FDG-labeled RBCs incubated in plasma. Just after intravenous injection of the optimized autologous ¹⁸F-FDG-labeled RBCs, dynamic PET scans were performed to evaluate in vivo imaging in normal rats and intraabdominal bleeding models (temporary and persistent bleeding).

Results

The optimal durations of glucose deprivation and incubation (labeling) with ¹⁸F-FDG were 60 and 30 min, respectively. As low as 10% of ¹⁸F was released as the form of ¹⁸F-FDG from ¹⁸F-FDG-labeled RBCs after a 60-min incubation. Dynamic PET images of normal rats showed strong persistence in the cardiovascular system for at least 120 min. In the intraabdominal bleeding models, ¹⁸F-FDG-labeled RBC PET visualized the extravascular blood clearly and revealed the dynamic changes of the extravascular radioactivity in the temporary and persistent bleeding.

Conclusions

RBCs can be effectively labeled with ¹⁸F-FDG and used for blood-pool imaging with PET in rats.

Electronic supplementary material

The online version of this article (doi:10.1186/s13550-017-0266-3) contains supplementary material, which is available to authorized users.

Radiation reduction and faster acquisition times with SPECT gated blood pool scans using a high-efficiency cardiac SPECT camera

BACKGROUND

Planar gated blood pool scans are an established method for the evaluation of left ventricular ejection fraction (LVEF) but the camera technology used for these studies has not significantly changed in decades. The purpose of this study was to determine the diagnostic accuracy of new high-efficiency SPECT gated blood pool scans compared to traditional scans and determine if they can be performed with lower radiation doses or faster acquisition times.

METHODS

Patients undergoing a planar gated blood pool scan on a Na-I SPECT camera who consented to participate were subsequently imaged for 5 minutes in "List Mode" using a high-efficiency SPECT camera. LVEF was calculated for both the planar study and at 1, 2, 3, 4, and 5 minutes of acquisition on the high-efficiency camera. Counts acquired in the field of view, counts in the cardiac blood pool and LVEF were compared.

RESULTS

A total of 46 patients were analyzed (48% male, mean age 55 years, and BMI 27.6 kg/m(2)) who received an average Tc-99m dose of 20.3 mCi (5.3 mSv), 17 (37%) with abnormal LVEF's. The Na-I camera averaged 24,514 counts/min/mCi in the field of view and 8662 counts/min/mCi in the cardiac blood pool while the high-efficiency camera averaged 65,219 counts/min/mCi and 41,427 counts/min/mCi, respectively. Compared to the planar calculation of LVEF, 1-minute SPECT LVEF was on average 8.6 ± 10.7 higher, 2 minutes 3.5 ± 7.6 higher, 3 minutes 2.9 ± 8.5 higher, 4 minutes 2.5 ± 7.0 higher, and 5 minutes 1.1 ± 6.2 higher. Good correlation was seen between the SPECT LVEF's and the planar LVEF's across all acquisition times with correlation coefficients of 0.74-0.93.

CONCLUSIONS

High-efficiency SPECT technology can reduce radiation exposure to patients during gated blood pool imaging or decrease acquisition time while maintaining diagnostic accuracy. Based on the improved count sensitivity with high-efficiency SPECT, a 50% reduction in injected activity may be achievable while maintaining short imaging times of 5 minutes, with further reduction possible at longer imaging times.

Comparison of biventricular ejection fractions using cadmium-zinc-telluride SPECT and planar equilibrium radionuclide angiography

BACKGROUND

We compared biventricular ejection fractions (EFs) from gated blood-pool single-photon emission computed tomography (SPECT) using a cadmium-zinc-telluride camera (CZT-SPECT) with planar equilibrium radionuclide angiography (ERNA) using a NaI gamma camera (NaI-planar). We also evaluated whether imaging time can be reduced without compromising image quality using the CZT camera.

METHODS

Forty-eight patients underwent NaI-planar and CZT-SPECT on the same day. CZT-SPECT datasets were re-projected at an LAO orientation similar to ERNA acquisition, forming CZT-repro planar datasets. The resulting biventricular volumetric measurements and EFs were compared.

RESULTS

LVEF calculated from CZT-SPECT and CZT-repro correlated better with NaI-planar (r = 0.93 and 0.99, respectively) than RVEF (r = 0.76 and 0.82, respectively). Excellent intra-class correlation and low bias in intra-observer comparisons were observed for the biventricular EFs derived from three datasets. A wider limit of agreement in CZT-SPECT-derived LVEFs, lower correlation and significant bias for NaI-planar, and CZT-repro-derived RVEFs was found in the inter-observer analyses. Nonetheless, the imaging time can be reduced to 4 minutes without increasing variability in EFs using the CZT camera (P = NS).

CONCLUSIONS

LVEFs calculated from CZT-SPECT and CZT-repro correlated well with NaI-planar. CZT camera may reduce imaging time while preserving image quality in the assessment of biventricular EFs.

Gated blood pool SPECT: The estimation of right ventricular volume and function is algorithm dependent in a clinical setting

BACKGROUND

Gated blood pool SPECT (GBPS) requires further validation for the assessment of the right ventricle (RV). This study evaluated three algorithms: BP-SPECT, QBS, and TOMPOOL (results are referred using this order). We compared (1) their "quantitative-accuracy": estimation of RV ejection fraction (EF), end-diastolic volume (EDV), and cardiac output (CO); (2) their "qualitative-accuracy": threshold values allowing diagnosing an impairment of the RV function; (3) their reproducibility: inter-observer relative variability (IOV).

METHODS AND RESULTS

Forty-eight consecutive patients underwent GBPS. Recommended reference standards were used: cardiac magnetic resonance imaging (CMR) (EDV, EF, n = 48), catheter measurements from thermodilution (TD) (CO, n = 25). (1) "Quantitative-accuracy": r = 0.42, 0.30, 0.42 for RVEF (CMR); r = 0.69, 0.77, 0.53 for RVEDV (CMR); 0.32, 0.36, 0.52 for RCO (TD). (2) "Qualitative-accuracy": optimal thresholds were 54.7%, 38.5%, 45.2% (AUC: 0.83, 0.80, 0.79) for RVEF; 229, 180, 94 mL (AUC: 0.83, 0.81, 0.81) for RVEDV; 4.1, 4.4, 2.6 L·minute(-1) (AUC: 0.73, 0.77, 0.80) for RCO. (3) Reproducibility: IOV was 5% ± 6%, 8% ± 12%, 17% ± 18% for RVEF; 6% ± 8%, 4% ± 4%, 21% ± 18% for RVEDV; 8% ± 8%, 11% ± 15%, 24% ± 20% for RCO.

CONCLUSION

Diagnostic accuracies are similar. A CMR-based calibration is required for a quantitative-analysis (cautious interpretation) or an accurate qualitative analysis (thresholds must be adjusted). Automatic procedures (BP-SPECT, QBS) offer the best compromise accuracy/reproducibility.

Global and regional functional assessment of ischemic heart disease with cardiac MR imaging

Cardiac MR imaging (CMR) combines assessment of myocardial function and tissue characterization, and is therefore ideally suited to evaluating patients with ischemic heart disease (IHD). This article discusses evaluation of left ventricular global function at CMR, reviewing the literature supporting global parameters in risk stratification and assessment of treatment response in IHD. Techniques for assessment of regional myocardial function are reviewed, and normal myocardial motion and fiber arrangement discussed. Despite barriers to clinical adoption, integration of this assessment into clinical routine should improve the ability to detect functional consequences of early myocardial structural alterations in patients with IHD.

Is TOMPOOL (gated blood-pool SPECT processing software) accurate to diagnose right and left ventricular dysfunction in a clinical setting?

BACKGROUND

The assessment of right ventricular function is crucial for management of heart disease. TOMPOOL is a software that processes data acquired with Tomographic Equilibrium Radionuclide Ventriculography. In this report, TOMPOOL's diagnostic accuracy and inter-observer reproducibility were assessed in a cohort of patients with various etiologies of ventricular dysfunction.

METHODS AND RESULTS

End-diastolic volume (EDV), ejection fraction (EF), and cardiac output (CO) were calculated for the right ventricle (RV) and the left ventricle (LV) using TOMPOOL in 99 consecutive patients. Thirty-five patients underwent cardiac magnetic resonance imaging (CMR) considered as the reference-standard to measure EDV and EF; the Spearman's rho correlation coefficients were r = 0.73/0.80 and 0.67/0.73 for right/left EF and EDV, respectively. Twenty-one patients had thermodilution measurements of right CO (reference-standard), the correlation was r = 0.57. The best cut-off points (sensitivity/specificity) in order to diagnose a ventricular dysfunction or enlargement were 46% for RVEF (67%/89%), 62% for LVEF (100%/90%), 94 mL for RVEDV (77%/73%), and 84 mL for LVEDV (100%/91%). The areas under the ROC curve were, respectively, 0.79, 0.91, 0.83, and 0.99. Inter-observer reproducibility was r = 0.81/0.94, 0.77/0.90, and 0.78/0.75 for Right/Left EF, EDV, and CO, respectively.

CONCLUSION

TOMPOOL is accurate: measurements of EDV, EF, and CO are reproducible and correlate with CMR and thermodilution. However, thresholds must be adjusted.

Assessment of an intermediate reprojection technique transitioning from planar to SPECT radionuclide ventriculography

BACKGROUND

The technique of SPECT-RNV (radionuclide ventriculography) offers a greater amount of clinically usable data than its planar counterpart (P-RNV). In transitioning from planar to SPECT-only acquisition methodologies, reprojection of the SPECT data can provide a planar dataset which can be used as an interim technique. The aim of this study was to test if reprojected planar images could be used as a surrogate for true planar images in SPECT-only setting.

METHODS

We performed SPECT-RNV and P-RNV on 47 patients on traditional sodium iodide (NaI) cameras, determining left ventricular ejection fractions (LVEF) for planar (EFP) and SPECT (EFS) techniques. We reprojected the SPECT-RNV data along the best septal separation angle determined from planar scanning. This creates a further planar dataset denoted 'reprojected P-RNV' (rP-RNV) giving a reprojected ejection fraction (EFR) which can be used as a validation variable in transitioning to SPECT-only acquisition.

RESULTS

Performing t tests showed no statistical difference between EFP and EFR (P > .017) but bias was observed in EFS results compared to EFP and EFS compared to EFR results. An unblinded, comparison of parametric data between the three datasets for a subset of ten patients showed good clinical concordance. False negative and false positive rates were low for rP-RNV compared to P-RNV.

CONCLUSIONS

The reprojected planar LVEF correlates well to P-RNV EF values. The rP-RNV dataset can aid clinicians in transitioning from planar RNV to SPECT-only acquisition.

Role of cardiac magnetic resonance in the evaluation of dilated cardiomyopathy: diagnostic contribution and prognostic significance

Dilated cardiomyopathy (DCM) represents the final common morphofunctional pathway of various pathological conditions in which a combination of myocyte injury and necrosis associated with tissue fibrosis results in impaired mechanical function. Recognition of the underlying aetiology of disease and accurate disease monitoring may be crucial to individually optimize therapeutic strategies and stratify patient's prognosis. In this regard, CMR has emerged as a new reference gold standard providing important information for differential diagnosis and new insight about individual risk stratification. The present review article will focus on the role of CMR in the evaluation of present condition, analysing respective strengths and limitations in the light of current literature and technological developments.

Gated F-18 FDG PET for assessment of left ventricular volumes and ejection fraction using QGS and 4D-MSPECT in patients with heart failure: a comparison with cardiac MRI

Purpose

Ventricular function is a powerful predictor of survival in patients with heart failure (HF). However, studies characterizing gated F-18 FDG PET for the assessment of the cardiac function are rare. The aim of this study was to prospectively compare gated F-18 FDG PET and cardiac MRI for the assessment of ventricular volume and ejection fraction (EF) in patients with HF.

Methods

Eighty-nine patients with diagnosed HF who underwent both gated F-18 FDG PET/CT and cardiac MRI within 3 days were included in the analysis. Left ventricular (LV) end-diastolic volume (EDV), end-systolic volume (ESV), and EF were obtained from gated F-18 FDG PET/CT using the Quantitative Gated SPECT (QGS) and 4D-MSPECT software.

Results

LV EDV and LV ESV measured by QGS were significantly lower than those measured by cardiac MRI (both P<0.0001). In contrast, the corresponding values for LV EDV for 4D-MSPECT were comparable, and LV ESV was underestimated with borderline significance compared with cardiac MRI (P = 0.047). LV EF measured by QGS and cardiac MRI showed no significant differences, whereas the corresponding values for 4D-MSPECT were lower than for cardiac MRI (P<0.0001). The correlations of LV EDV, LV ESV, and LV EF between gated F-18 FDG PET/CT and cardiac MRI were excellent for both QGS (r = 0.92, 0.92, and 0.76, respectively) and 4D-MSPECT (r = 0.93, 0.94, and 0.75, respectively). However, Bland-Altman analysis revealed a significant systemic error, where LV EDV (−27.9±37.0 mL) and ESV (−18.6±33.8 mL) were underestimated by QGS.

Conclusion

Despite the observation that gated F-18 FDG PET/CT were well correlated with cardiac MRI for assessing LV function, variation was observed between the two imaging modalities, and so these imaging techniques should not be used interchangeably.

Left ventricular ejection fraction and volumes: it depends on the imaging method

Background and Methods

In order to provide guidance for using measurements of left ventricular (LV) volume and ejection fraction (LVEF) from different echocardiographic methods a PubMed review was performed on studies that reported reference values in normal populations for two-dimensional (2D ECHO) and three-dimensional (3D ECHO) echocardiography, nuclear imaging, cardiac computed tomography, and cardiac magnetic resonance imaging (CMR). In addition all studies (2 multicenter, 16 single center) were reviewed, which included at least 30 patients, and the results compared of noncontrast and contrast 2D ECHO, and 3D ECHO with those of CMR.

Results

The lower limits for normal LVEF and the normal ranges for end-diastolic (EDV) and end-systolic (ESV) volumes were different in each method. Only minor differences in LVEF were found in studies comparing CMR and 2D contrast echocardiography or noncontrast 3D echocardiography. However, EDV and ESV measured with all echocardiographic methods were smaller and showed greater variability than those derived from CMR. Regarding agreement with CMR and reproducibility, all studies showed superiority of contrast 2D ECHO over noncontrast 2D ECHO and 3D ECHO over 2D ECHO. No final judgment can be made about the comparison between contrast 2D ECHO and noncontrast or contrast 3D ECHO.

Conclusion

Contrast 2D ECHO and noncontrast 3D ECHO show good reproducibility and good agreement with CMR measurements of LVEF. The agreement of volumes is worse. Further studies are required to assess the clinical value of contrast 3D ECHO as noncontrast 3D ECHO is only reliable in patients with good acoustic windows.