Equilibrium radionuclide angiocardiography

Assessment of the Right Ventricle Function in Patients With Significant Tricuspid Regurgitation: A Review

Tricuspid regurgitation (TR) is an increasingly prevalent condition, especially in older populations, and presents significant challenges due to its association with right heart failure, hospital admissions, and high mortality rates. The management of TR has evolved, with new percutaneous valve repair and replacement techniques emerging alongside traditional surgical approaches. However, accurately assessing right ventricular (RV) function-a key prognostic factor in TR-remains difficult due to the RV's unique anatomy and sensitivity to loading conditions. Current echocardiographic methods, such as Tricuspid Annular Plane Systolic Excursion (TAPSE), S' wave analysis, and RV fractional area change (FAC), offer valuable insights but have limitations, particularly regarding load dependence and incomplete assessment of RV function. Advances in 3D echocardiography and myocardial strain imaging provide more comprehensive evaluations, yet challenges persist in integrating these measures in routine clinical practice. The review highlights the importance of a multimodal approach to RV assessment in TR patients, considering both the right atrium and pulmonary artery interactions, and explores potential future tools such as myocardial work and dynamic testing to improve prognostic accuracy and patient outcomes.

Fully Automatic Quantitative Measurement of Equilibrium Radionuclide Angiocardiography Using a Convolutional Neural Network

PURPOSE

The aim of this study was to generate deep learning-based regions of interest (ROIs) from equilibrium radionuclide angiography datasets for left ventricular ejection fraction (LVEF) measurement.

PATIENTS AND METHODS

Manually drawn ROIs (mROIs) on end-systolic and end-diastolic images were extracted from reports in a Picture Archiving and Communications System. To reduce observer variability, preprocessed ROIs (pROIs) were delineated using a 41% threshold of the maximal pixel counts of the extracted mROIs and were labeled as ground-truth. Background ROIs were automatically created using an algorithm to identify areas with minimum counts within specified probability areas around the end-systolic ROI. A 2-dimensional U-Net convolutional neural network architecture was trained to generate deep learning-based ROIs (dlROIs) from pROIs. The model's performance was evaluated using Lin's concordance correlation coefficient (CCC). Bland-Altman plots were used to assess bias and 95% limits of agreement.

RESULTS

A total of 41,462 scans (19,309 patients) were included. Strong concordance was found between LVEF measurements from dlROIs and pROIs (CCC = 85.6%; 95% confidence interval, 85.4%-85.9%), and between LVEF measurements from dlROIs and mROIs (CCC = 86.1%; 95% confidence interval, 85.8%-86.3%). In the Bland-Altman analysis, the mean differences and 95% limits of agreement of the LVEF measurements were -0.6% and -6.6% to 5.3%, respectively, for dlROIs and pROIs, and -0.4% and -6.3% to 5.4% for dlROIs and mROIs, respectively. In 37,537 scans (91%), the absolute LVEF difference between dlROIs and mROIs was <5%.

CONCLUSIONS

Our 2-dimensional U-Net convolutional neural network architecture showed excellent performance in generating LV ROIs from equilibrium radionuclide angiography scans. It may enhance the convenience and reproducibility of LVEF measurements.

A predictive model of super response to cardiac resynchronization therapy in short-term period

BACKGROUND

The left bundle branch block, nonischemic heart failure (HF) and female gender are the most powerful predictors of a super response to cardiac resynchronization therapy (CRT). It is important to identify super responders who can derive most benefits from CRT. We aimed to establish a predicting model that could be used for prognosis of a super response to CRT in short-term period.

METHODS

Patients with QRS ≥ 130 ms, New York Heart Association (NYHA) II-III class of HF, left ventricle ejection fraction (LVEF) ≤ 35% and indications for CRT were included in the study. Before and 6 month after CRT the electrocardiography, echocardiography and cardiac scintigraphy were performed. The study's primary endpoint was the NYHA class improvement ≥ 1 and left ventricle end systolic volume decrease > 30% or LVEF improvement > 15% after 6 month CRT. Based on collected data, we developed a predictive model regarding a super response to CRT.

RESULTS

Of 49 (100.0%) patients, 32 (65.3%) had a super response to CRT. Patients with a super response were likelier to have a lower cardiac index (p = 0.007), higher rates of interventricular delay (IVD) (p = 0.003), phase standard deviation of left ventricle anterior wall (PSD LVAW) (p = 0.009) and ∆QRS (p = 0.02). Only IVD and PSD LVAW were independently associated with a super response to CRT in univariate and multivariate logistic regression. We created a logistic equation and calculated a cut-off value. The resulting ROC curve revealed a discriminative ability with AUC of 0.812 (sensitivity 90.62%; specificity 70.59%).

CONCLUSION

Our predictive model is able to distinguish patients with a super response to CRT.

Comparison of Echocardiography and Multi-Planar Gated Acquisition Scans for Predicting Cancer-Treatment-Related Cardiovascular Dysfunction

BACKGROUND

Current guidelines recommend using sequential cardiac imaging to monitor for cancer treatment-related cardiac dysfunction (CTRCD) in patients undergoing potentially cardiotoxic chemotherapy. Multiple different imaging cardiac modalities are available and there are few prospective head-to-head comparative studies to help guide treatment.

OBJECTIVES

To perform an exploratory prospective cohort study of "real-world" CTRCD comparing multigated acquisition nuclear ventriculography (MUGA) at the referring cancer specialist's discretion with a novel echocardiographic strategy at an Australian tertiary hospital.

METHOD

Patients were recruited from haematology and oncology outpatient clinics if they were scheduled for treatment with anthracyclines and/or trastuzumab. Patients underwent simultaneous MUGA-based cardiac imaging (conventional strategy) at a frequency according to evidenced-based guidelines in addition to researcher-conducted echocardiographic imaging. The echocardiographic imaging was performed in all patients at time points recommended by international society guidelines. Outcomes included adherence to guideline recommendations, concordance between MUGA and echocardiographic left ventricular ejection fraction (LVEF) measurements, and detection of cardiac dysfunction (defined as >5% LVEF decrement from baseline by three-dimensional [3D]-LVEF). A secondary end point was accuracy of global longitudinal strain in predicting cardiac dysfunction.

RESULTS

In total, 35 patients were recruited, including 15 with breast cancer, 19 with haematological malignancy, and one with gastric cancer. MUGA and echocardiographic LVEF measurements correlated poorly with limits of agreement of 30% between 3D-LVEF and MUGA-LVEF and 37% for 3D-LVEF and MUGA-LVEF. Only one case (2.9%) of CTRCD was diagnosed by MUGA, compared with 12 (34.2%) cases by echocardiography. Four (4) patients had >10% decrement in 3D-LVEF that was not detected by MUGA. Global longitudinal strain at 2 months displayed significant ability to predict CTRCD (area under the curve, 0.75, 95% confidence interval, 0.55-0.94).

CONCLUSIONS

The MUGA correlates poorly with echocardiographic assessment with substantial discrepancy between MUGA and echocardiography in CTRCD diagnosis. Echocardiographic and MUGA imaging strategies should not be considered equivalent for imaging cancer patients, and a single imaging modality should ideally be used per patient to prevent misdiagnosis by inter-modality variation These findings should be considered hypothesis-generating and require confirmation with larger studies.

The Value of Stress-Gated Blood Pool SPECT in Predicting Early Postoperative Period Complications in Ischemic Cardiomyopathy Patients: Focus on Mechanical Dyssynchrony

(1) Objective: The objective of this study was to assess the prognostic value of stress-gated blood pool SPECT (GBPS) estimates in patients with ischemic cardiomyopathy (ICM) in the early postoperative period. (2) Methods: A total of 57 patients (age 59.7 ± 6.6, 47 men) with ICM and LV ejection fraction (30 [27.5; 35]%) were enrolled in the study. Before surgical treatment, all patients underwent GBPS (rest-stress, dobutamine doses of 5/10/15 µg/kg/min). Stress-induced changes in left ventricular (LV) ejection fraction, peak ejection rate, volumes, and mechanical dyssynchrony (phase histogram standard deviation, phase entropy (PE), and phase histogram bandwidth) were estimated. Two-dimensional transthoracic echocardiography was performed baseline. Serum levels of NT-proBNP were analyzed with enzyme-linked immunoassay. (3) Results: After surgical treatment, patients were divided into two groups, one, with death, the need for an intra-aortic balloon pump (IABP) or/and inotropic support with a stay in the intensive care unit for more than two days and two, without complications in the early postoperative period (EPOP). Complicated EPOP (CEPOP) was observed in 17 (30%) patients (death-2, IABP-4, extra inotropic support in intensive care unit-11), and 40 patients had no complications (NCEPOP). GBPS showed differences in LV EDV (mL) (321 [268; 358] vs. 268 [242; 313], p = 0.02), LV ESV (mL) (242 [201; 282] vs. 196 [170; 230], p = 0.005), and stress-induced changes in PE (1 (-2; 3) vs. -2 (-4; 0), p = 0.02). Aortic cross-clamp time and stress-induced changes in PE between rest and dobutamine dose of 10 µg/kg/min were the only independent predictors of CEPOP. An increase in LV entropy ≥ 1 on the dobutamine dose of 10µg/kg/min in comparison to rest investigation showed AUC = 0.853 (sensitivity = 62%, specificity = 90%, PPV = 71%; NPV = 85%; p < 0.0001). Conclusion: Stress-induced changes in PE obtained during low-dose dobutamine GBPS are associated with a complicated course of the early postoperative period after surgical treatment for ICM.

Does cardiac imaging surveillance strategy influence outcomes in patients with early breast cancer?

Background

Many patients with breast cancer receive therapies with the potential to cause cardiotoxicity. Echocardiography and multiple-gated acquisition (MUGA) scans are the most used modalities to assess cardiac function during treatment in high-risk patients; however, the optimal imaging strategy and the impact on outcome are unknown.

Methods

Consecutive patients with stage 0-3 breast cancer undergoing pre-treatment echocardiography or MUGA were identified from a tertiary care cancer center from 2010-2019. Demographics, medical history, imaging data and clinical events were collected from hospital charts and administrative databases. The primary outcome is a composite of all-cause death or heart failure event. Clinical and imaging predictors of outcome were evaluated on univariable and multivariable analyses.

Results

1028 patients underwent pre-treatment MUGA and 1032 underwent echocardiography. The groups were well matched for most clinical characteristics except patients undergoing MUGA were younger, had more stage 3 breast cancer and more HER2 over-expressing and triple negative cases. Routine follow-up cardiac imaging scan was obtained in 39.3% of patients with MUGA and 38.0% with echocardiography. During a median follow-up of 2448 (1489, 3160) days, there were 194 deaths, including 7 cardiovascular deaths, and 28 heart failure events with no difference in events between the MUGA and echocardiography groups. There were no imaging predictors of the primary composite outcome or cardiac events. Patients without follow-up imaging had similar adjusted risk for the composite outcome compared to those with imaging follow-up, hazard ratio 0.8 (95% confidence interval 0.5,1.3), p=0.457.

Conclusion

The selection of pretreatment echocardiography or MUGA did not influence the risk of death or heart failure in patients with early breast cancer. Many patients did not have any follow-up cardiac imaging and did not suffer worse outcomes. Cardiovascular deaths and heart failure event rates were low and the value of long-term cardiac imaging surveillance should be further evaluated.

The Value of Left Ventricular Mechanical Dyssynchrony and Scar Burden in the Combined Assessment of Factors Associated with Cardiac Resynchronization Therapy Response in Patients with CRT-D

Background: Cardiac resynchronization therapy (CRT) improves the outcome in patients with heart failure (HF). However, approximately 30% of patients are nonresponsive to CRT. The aim of this study was to determine the role of the left ventricular (LV) mechanical dyssynchrony (MD) and scar burden as predictors of CRT response. Methods: In this study, we included 56 patients with HF and the left bundle-branch block with QRS duration ≥ 150 ms who underwent CRT-D implantation. In addition to a full examination, myocardial perfusion imaging and gated blood-pool single-photon emission computed tomography were performed. Patients were grouped based on the response to CRT assessed via echocardiography (decrease in LV end-systolic volume ≥15% or/and improvement in the LV ejection fraction ≥5%). Results: In total, 45 patients (80.3%) were responders and 11 (19.7%) were nonresponders to CRT. In multivariate logistic regression, LV anterior-wall standard deviation (adjusted odds ratio (OR) 1.5275; 95% confidence interval (CI) 1.1472–2.0340; p = 0.0037), summed rest score (OR 0.7299; 95% CI 0.5627–0.9469; p = 0.0178), and HF nonischemic etiology (OR 20.1425; 95% CI 1.2719–318.9961; p = 0.0331) were the independent predictors of CRT response. Conclusion: Scar burden and MD assessed using cardiac scintigraphy are associated with response to CRT.

Polarity status of trigger signal during ECG-gating affects parameters of LV function in gated myocardial perfusion SPECT

INTRODUCTION AND BACKGROUND

The polarity status is one of the important items of specifications of trigger signal from cardiac trigger monitors with two options, either positive or negative. Some systems allow the user to set the polarity of trigger signal before imaging. Efforts should be made to set the polarity status according to the recommendations provided by the manufacturers. In case of inappropriate selection, changes in computation of end-systolic and end-diastolic volumes as well as ejection fraction may occur.

OBJECTIVE

To investigate the effect of the polarity status of trigger signals in synchronization process during 8- and 16-frame gated SPECT imaging on the systolic and diastolic parameters of LV function.

METHODS

Thirty-four patients referred for a myocardial perfusion SPECT were consecutively included in the study. The rest scan for each patient was performed with 8- and 16-frame gating simultaneously with positive trigger signal set by the operator in a cardiac trigger monitor and then repeated after manual selection of negative polarity. In total, the 4 imaging modes acquired were 8-frame/positive-trigger, 16-frame/positive-trigger, 8-frame/negative-trigger, and 16-frame/negative-trigger. All SPECT images were reconstructed and processed with the same values of parameters. Systolic and diastolic indices of LV function were derived in QGS of the Cedars-Sinai software and then were compared using various statistical tests, and a reliability analysis was also performed.

RESULTS

The age of patients recruited in the study was 58.41 ± 8.94, and 16 (47.1%) males and 18 (52.9%) females. All the correlation coefficients between corresponding parameters in positive and negative trigger signals were statistically significant. The difference between the parameters of systolic function including EF, EDV, and ESV in positive and negative trigger signals was statistically significant in paired sample t test. Likewise, a statistically significant difference was also found between mean phase angle in scans with positive and negative trigger signals by a phase difference of 147.91 (41.0% of an average cardiac cycle) and 149 (41.3% of an average cardiac cycle) degrees in 8- and 16-frame gating modes, respectively. Strong agreement (according to high values of intra-class correlation coefficient) was found for all four pairs. According to Bland-Altman results, an offset of about 3 percentage units was found, both between imaging in 8-frame gating compared to 16-frame gating, higher value in favor of 16-frame gating, and also between imaging with positive polarity trigger compared to negative-polarity trigger, again higher value in favor of positive-polarity triggering.

CONCLUSION

The status of the polarity of trigger signals or similar CTM-camera delays in synchronization process during 8- and 16-frame gated SPECT imaging can be considered as one of the factors that may influence systolic and diastolic indices of LV function.

Nuclear medicine imaging methods of radiation-induced cardiotoxicity

Breast cancer survival is significantly improved over the past decades due to major improvements in anti-tumor therapies and the implementation of regular screening, which leads to early detection of breast cancer. Therefore, it is of utmost importance to prevent patients from long-term side effects, including radiotherapy-induced cardiotoxicity. Radiotherapy may contribute to damage of myocardial structures on the cellular level, which eventually could result in various types of cardiovascular problems, including coronary artery disease and (non-)ischemic cardiomyopathy, leading to heart failure. These cardiac complications of radiotherapy are preceded by alterations in myocardial perfusion and blood flow. Therefore, early detection of these alterations is important to prevent the progression of these pathophysiological processes. Several radionuclide imaging techniques may contribute to the early detection of these changes. Single-Photon Emission Computed Tomography (SPECT) cameras can be used to create Multigated Acquisition scans in order to assess the left ventricular systolic and diastolic function. Furthermore, SPECT cameras are used for myocardial perfusion imaging with radiopharmaceuticals such as ^99mTc-sestamibi and ^99mTc-tetrofosmin. Accurate quantitative measurement of myocardial blood flow (MBF), can be performed by Positron Emission Tomography (PET), as the uptake of some of the tracers used for PET-based MBF measurement almost creates a linear relationship with MBF, resulting in very accurate blood flow quantification. Furthermore, there are PET and SPECT tracers that can assess inflammation and denervation of the cardiac sympathetic nervous system. Research over the past decades has mainly focused on the long-term development of left ventricular impairment and perfusion defects. Considering laterality of the breast cancer, some early studies have shown that women irradiated for left-sided breast cancer are more prone to cardiotoxic side effects than women irradiated for right-sided breast cancer. The left-sided radiation field in these trials, which predominantly used older radiotherapy techniques without heart-sparing techniques, included a larger volume of the heart and left ventricle, leading to increased unavoidable radiation exposure to the heart due to the close proximity of the radiation treatment volume. Although radiotherapy for breast cancer exposes the heart to incidental radiation, several improvements and technical developments over the last decades resulted in continuous reduction of radiation dose and volume exposure to the heart. In addition, radiotherapy reduces loco-regional tumor recurrences and death from breast cancer and improves survival. Therefore, in the majority of patients, the benefits of radiotherapy outweigh the potential very low risk of cardiovascular adverse events after radiotherapy. This review addresses existing nuclear imaging techniques, which can be used to evaluate (long-term) effects of radiotherapy-induced mechanical cardiac dysfunction and discusses the potential use of more novel nuclear imaging techniques, which are promising in the assessment of early signs of cardiac dysfunction in selected irradiated breast cancer patients.

Low-dose dobutamine stress gated blood pool SPECT assessment of left ventricular contractile reserve in ischemic cardiomyopathy: a feasibility study

PURPOSE

The purpose of the present study was to evaluate the feasibility of gated blood pool single-photon emission computed tomography (GBPS) with low-dose dobutamine (LDD) stress test, performed on a single-photon emission computed tomography (SPECT) camera equipped with cadmium-zinc-telluride (CZT) solid-state detectors, in assessing of left ventricle (LV) contractile reserve in patients with ischemic cardiomyopathy (ICM).

METHODS

A total of 52 patients (age 59 ± 7.2 years, 47 men and 5 women) with ICM and a control group of 10 patients without obstructive coronary artery lesion underwent GBPS and transthoracic echocardiography (TTE) at rest and during LDD stress test (5, 10, 15 µg/kg/min). The duration of each GBPS step was 5 min. Stress-induced changes in LV ejection fraction (ΔLVEF), peak ejection rate, LV volumes, and mechanical dyssynchrony (phase histogram standard deviation, phase histogram bandwidth and entropy) obtained with GBPS were estimated.

RESULTS

All GBPS indices except end-diastolic volume showed significant dynamics during stress test in both groups. The majority of parameters in ICM patients showed significant changes at a dobutamine dose of 10 µg/kg/min as compared to the rest study. Seventeen percent of ICM patients, but none from the control group, showed a decrease in LVEF during stress, accompanied by a significant increase in entropy. The intra- and inter-observer reproducibility was excellent for both rest and stress studies. There was a moderate correlation (r = 0.5, p = 0.01) between GBPS and TTE, with a mean difference value of - 1.7 (95% confidence interval - 9.8; 6.4; p = 0.06) in ΔLVEF.

CONCLUSION

Low-dose dobutamine stress GBPS performed with high-efficiency CZT-SPECT cameras can be performed for evaluating stress-induced changes in LV contractility and dyssynchrony with lower acquisition time. A dobutamine dose of 10 µg/kg/min can potentially suffice to detect stress-induced changes in patients with ICM during GBPS.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT04508608 (August 7, 2020).

Equilibrium radionuclide angiography: Intra- and inter-observer repeatability and reproducibility in the assessment of cardiac systolic and diastolic function

BACKGROUND

This study aimed to assess intra- and inter-observer agreement in assessing the systolic and diastolic function with equilibrium radionuclide angiography (ERNA).

MATERIALS AND METHODS

Thirty-two adults underwent baseline and repeat ERNA. An experienced and a trainee operator analyzed the data by assigning regions of interest manually, fully automatically, and semi-automatically. The Bland-Altman statistic (mean ± 1.96 standard deviations of the differences) was used to assess the repeatability (two different assessments of a single acquisition) and reproducibility (assessments of two different acquisitions).

RESULTS

Using the semi-automated technique the intraobserver repeatability and reproducibility of left ventricular ejection fraction for the experienced physician were - 0.1 ± 3.7 and 0.0 ± 3.8 and for the trainee 2.2 ± 10.6 and 1.9 ± 8.4, respectively. The inter-observer repeatability and reproducibility were - 1.8 ± 6.4 and 0.4 ± 9.0, respectively. Among the parameters of diastolic function, the intraobserver repeatability and reproducibility of the peak filling rate for the experienced physician were - 0.0 ± 1.1 and - 0.1 ± 1.1 and for the trainee 0.2 ± 3.5 and 0.4 ± 3.7, respectively. The inter-observer repeatability and reproducibility were 0.3 ± 1.5 and 0.5 ± 4.0, respectively. Similar was the pattern for the other diastolic indices. In all cases the limits of agreement varied according to the quantification approach.

CONCLUSION

A good repeatability but a moderate reproducibility was found in the assessment of the LVEF. Less good were the findings in the assessment of diastolic function.

Left ventricle function assessment using gated first-pass 18F-FDG PET: Validation against equilibrium radionuclide angiography

PURPOSE

We appraised the feasibility of left ventricle (LV) function assessment using gated first-pass 18F-FDG PET, and assessed the concordance of the produced measurements with equilibrium radionuclide angiography (ERNA).

MATERIALS AND METHODS

Twenty-four oncologic patients benefited from 99mTc-labeled red-blood-cell ERNA, in planar mode (all patients) and using SPECT (22 patients). All patients underwent gated first-pass 18F-FDG cardiac PET. Gated dynamic PET images were reconstructed over 1 minute during tracer first-pass inside the LV and post-processed using in-house software (TomPool). After re-orientation into cardiac canonical axes and adjustment of the valves plane using a phase image, pseudo-planar PET images obtained by re-projection were automatically segmented using thresholded region growing and gradient-based delineation to produce an LV ejection fraction (EF) estimate. PET images were also post-processed in fully-tomographic mode to produce LV end diastole volume (EDV), end systole volume (ESV), and EF estimates. Concordance was assessed using Lin's concordance (ccc) and Bland-Altman analysis. Reproducibility was assessed using the coefficient of variation (CoV) and intra-class correlation (ICC).

RESULTS

Pseudo-planar PET EF estimates were concordant with planar ERNA (ccc = 0.81, P < .001) with a bias of 0% (95% CI [- 2%; 3%], limits of agreement [- 11%; 12%]). Reproducibility was excellent and similar for both methods (CoV = 2 ± 1% and 3 ± 2%, P = NS; ICC = 0.97 and 0.92, for PET and ERNA, respectively). Measurements obtained in fully-tomographic mode were concordant with SPECT ERNA: ccc = 0.83 and bias = - 3 mL for LV EDV, ccc = 0.92 and bias = 0 mL for LV ESV, ccc = 0.89 and bias = - 1% for LV EF (all P values < .001 for ccc, all biases not significant).

CONCLUSIONS

Gated first-pass 18F-FDG PET might stand as a relevant alternative to ERNA for LV function assessment, enabling a joint evaluation of both therapeutic response and cardiac toxicity in oncologic patients receiving cardiotoxic chemotherapy.

Technical Aspects and Errors of Triggering and Synchronization in Gated Single Photon Emission Computed Tomography Myocardial Perfusion Imaging

Gated imaging, as a technically demanding procedure, requires special attention and effort to fulfill the technical adequacy and accuracy of the study, based on the available standard guidelines. One of the essential requirements to be met by both technologists and physicians, in nuclear cardiology, is triggering and synchronization as a fundamental subject of gating. There are many sources of gating errors that produce imaging artifacts and, in some occasions, render the images uninterpretable or the quantitative analyses less accurate. Sufficient knowledge of recognition of these artifacts and understanding of their related mechanisms (from physical and technical perspectives) enable the technologists and physicians to promote their performance in daily practice. In this article, intended as a readily practical technical review for nuclear medicine practitioners, it is aimed to present the technical and computer aspects of triggering and synchronization as well as the related errors during imaging.

The Utility of Cardiac Reserve for the Early Detection of Cancer Treatment-Related Cardiac Dysfunction: A Comprehensive Overview

With progressive advancements in cancer detection and treatment, cancer-specific survival has improved dramatically over the past decades. Consequently, long-term health outcomes are increasingly defined by comorbidities such as cardiovascular disease. Importantly, a number of well-established and emerging cancer treatments have been associated with varying degrees of cardiovascular injury that may not emerge until years following the completion of cancer treatment. Of particular concern is the development of cancer treatment related cardiac dysfunction (CTRCD) which is associated with an increased risk of heart failure and high risk of morbidity and mortality. Early detection of CTRCD appears critical for preventing long-term cardiovascular morbidity in cancer survivors. However, current clinical standards for the identification of CTRCD rely on assessments of cardiac function in the resting state. This provides incomplete information about the heart's reserve capacity and may reduce the sensitivity for detecting sub-clinical myocardial injury. Advances in non-invasive imaging techniques have enabled cardiac function to be quantified during exercise thereby providing a novel means of identifying early cardiac dysfunction that has proved useful in several cardiovascular pathologies. The purpose of this narrative review is (1) to discuss the different non-invasive imaging techniques that can be used for quantifying different aspects of cardiac reserve; (2) discuss the findings from studies of cancer patients that have measured cardiac reserve as a marker of CTRCD; and (3) highlight the future directions important knowledge gaps that need to be addressed for cardiac reserve to be effectively integrated into routine monitoring for cancer patients exposed to cardiotoxic therapies.

Gated Tomographic Radionuclide Angiography Using CZT Gamma Camera in Patients Receiving Cardiotoxic Chemotherapy: Going Faster and Less Irradiating

Tomographic radionuclide angiography (TRNA) can monitor cardiac function in patients receiving cardiotoxic chemotherapy. Gamma cameras using CZT detectors enable dose reduction and quicker acquisitions. We report 80 patients who underwent a 7-minute TRNA acquisition after injection of 550-MBq Tc-labeled human serum albumin. Data were analyzed full and half. Image quality was not visually decreased. There was no significant difference in left ventricular systolic and diastolic volumes and in left and right ventricular ejection fractions between full and half data acquisitions (P < 0.0001). When injecting half activity, effective dose could be reduced to 1.92 mSv.

Diastolic dysfunction can precede systolic dysfunction on MUGA in cancer patients receiving trastuzumab-based therapy

Background

Trastuzumab (T) and anthracycline (A)-based chemotherapy is considered the standard of care in human epidermal growth factor receptor-2+ overexpressing breast cancer, but requires monitoring for known cardiotoxicity using left ventricular (LV) ejection fraction (EF) every 3–4 months during treatment. It is not conclusively established whether diastolic dysfunction (DD) precedes LVEF decrease in patients developing trastuzumab-induced cardiotoxicity (TIC).

Objective

The aim was to elucidate whether DD precedes LVEF decrease in trastuzumab-treated patients being monitored with radionuclide multigated acquisition for TIC.

Patients and methods

Patients treated with T±A-based chemotherapy who had undergone multigated acquisition were selected by date range (January 2006–September 2015). Up to four scans were analyzed per patient: (a) pre-A therapy, (b) pre-T therapy, (c) 4 months into T therapy, and (d) at end of T therapy. Baseline referred to the first scan of each patient (i.e. pre-A or pre-T). LV systolic and DD were defined as follows: EF less than 50% or a 10-point decrease from baseline and LV peak filling rate (PFR) less than 2.5 end-diastolic volume/s and time to peak LV filling rates (TPFR) greater than 180 ms, respectively.

Results

A total of 202 patients were screened for this study, of whom 153 had received A therapy (5.1±4.1 months duration) before T, 192 had 4 months of follow-up data, and 146 had 4 months of follow-up data and beyond (10.5±5.0 months). LVEF decreased with A and T therapy (P<0.005), but remained stable between 4 months and the final exam (P=0.26). In patients with normal diastolic function at baseline (45.5%), PFR decreased with A and T, and DD preceded SD by 73 days on average. In the remaining patients, with abnormal diastolic function at baseline (54.5%), PFR did not change over the course of treatment (P>0.1), nor did TPFR (P>0.3).

Conclusion

Patients with normal diastolic function at baseline receiving trastuzumab±anthracycline adjuvant therapy may develop DD before SD, therefore offering an opportunity for early referral to cardiologists to optimize cardiovascular risk factors and manage cardiotoxicity.

Assessment of LVEF using a new 16-segment wall motion score in echocardiography

Background

Simpson biplane method and 3D by transthoracic echocardiography (TTE), radionuclide angiography (RNA) and cardiac magnetic resonance imaging (CMR) are the most accepted techniques for left ventricular ejection fraction (LVEF) assessment. Wall motion score index (WMSI) by TTE is an accepted complement. However, the conversion from WMSI to LVEF is obtained through a regression equation, which may limit its use. In this retrospective study, we aimed to validate a new method to derive LVEF from the wall motion score in 95 patients.

Methods

The new score consisted of attributing a segmental EF to each LV segment based on the wall motion score and averaging all 16 segmental EF into a global LVEF. This segmental EF score was calculated on TTE in 95 patients, and RNA was used as the reference LVEF method. LVEF using the new segmental EF 15-40-65 score on TTE was compared to the reference methods using linear regression and Bland–Altman analyses.

Results

The median LVEF was 45% (interquartile range 32–53%; range from 15 to 65%). Our new segmental EF 15-40-65 score derived on TTE correlated strongly with RNA-LVEF (r = 0.97). Overall, the new score resulted in good agreement of LVEF compared to RNA (mean bias 0.61%). The standard deviations (s.d.s) of the distributions of inter-method difference for the comparison of the new score with RNA were 6.2%, indicating good precision.

Conclusion

LVEF assessment using segmental EF derived from the wall motion score applied to each of the 16 LV segments has excellent correlation and agreement with a reference method.

In vivo Exposure Effects of 99mTc-methoxyisobutylisonitrile on the FDXR and XPA Genes Expression in Human Peripheral Blood Lymphocytes

Objective(s):

In recent years, the application of radiopharmaceuticals in nuclear medicine has increased substantially. Following the diagnostic procedures performed in nuclear medicine departments, such as myocardial perfusion imaging, patients generally receive considerable doses of radiation. Normally, radiation-induced DNA damages are expected following exposure to a low-dose ionizing radiation. In order to detect molecular changes, high-sensitivity techniques must be utilized. The aim of this study was to assess the effect of a low-dose (below 10 mSv) gamma ray on gene expression using quantitative real-time polymerase chain reaction (qRT-PCR).

Methods:

Blood samples were obtained from 20 volunteer patients who underwent myocardial perfusion imaging. They were given various doses of Technetium-99m methoxyisobutylisonitrile (^99mTc-MIBI). After that, peripheral blood mononuclear cells (PBMNs) were derived, and then total RNA was extracted and reverse-transcribed to cDNA. Finally, the expression levels of xeroderma pigmentosum complementation group-A (XPA) and ferredoxin reductase (FDXR) genes were determinded through qRT-PCR technique using SYBR Green.

Results:

XPA and FDXR expression levels were obtained following a very low-dose ionizing radiation. A significant up-regulation of both genes was observed, and the gene expression level of each individual patient was different. If differences in the administered activity and radiosensitivity are taken into account, the observed differences could be justified. Furthermore, gender and age did not play a significant role in the expression levels of the genes under study.

Conclusion:

The up-regulation of FDXR after irradiation revealed the high-sensitivity level of this gene; therefore, it could be used as an appropriate biomarker for biological dosimetry. On the other hand, the up-regulation of XPA is an indication of DNA repair following radiation exposure. According to linear no-threshold model (LNT) and the results obtained from this study, a very low dose of ionizing radiation could bring about adverse biological effects at molecular level in the irradiated person.

Comparison between Radionuclide Ventriculography and Echocardiography for Quantification of Left Ventricular Systolic Function in Rats Exposed to Doxorubicin

Background

Radionuclide ventriculography (RV) is a validated method to evaluate the left ventricular systolic function (LVSF) in small rodents. However, no prior study has compared the results of RV with those obtained by other imaging methods in this context.

Objectives

To compare the results of LVSF obtained by RV and echocardiography (ECHO) in an experimental model of cardiotoxicity due to doxorubicin (DXR) in rats.

Methods

Adult male Wistar rats serving as controls (n = 7) or receiving DXR (n = 22) in accumulated doses of 8, 12, and 16 mg/kg were evaluated with ECHO performed with a Sonos 5500 Philips equipment (12-MHz transducer) and RV obtained with an Orbiter-Siemens gamma camera using a pinhole collimator with a 4-mm aperture. Histopathological quantification of myocardial fibrosis was performed after euthanasia.

Results

The control animals showed comparable results in the LVSF analysis obtained with ECHO and RV (83.5 ± 5% and 82.8 ± 2.8%, respectively, p > 0.05). The animals that received DXR presented lower LVSF values when compared with controls (p < 0.05); however, the LVSF values obtained by RV (60.6 ± 12.5%) were lower than those obtained by ECHO (71.8 ± 10.1%, p = 0.0004) in this group. An analysis of the correlation between the LVSF and myocardial fibrosis showed a moderate correlation when the LVSF was assessed by ECHO (r = -0.69, p = 0.0002) and a stronger correlation when it was assessed by RV (r = -0.79, p < 0.0001). On multiple regression analysis, only RV correlated independently with myocardial fibrosis.

Conclusion

RV is an alternative method to assess the left ventricular function in small rodents in vivo. When compared with ECHO, RV showed a better correlation with the degree of myocardial injury in a model of DXR-induced cardiotoxicity.

Accuracy of left ventricular ejection fraction by contemporary multiple gated acquisition scanning in patients with cancer: comparison with cardiovascular magnetic resonance

BACKGROUND

Multiple gated acquisition scanning (MUGA) is a common imaging modality for baseline and serial assessment of left ventricular ejection fraction (LVEF) for cardiotoxicity risk assessment prior to, surveillance during, and surveillance after administration of potentially cardiotoxic cancer treatment. The objective of this study was to compare the accuracy of left ventricular ejection fractions (LVEF) obtained by contemporary clinical multiple gated acquisition scans (MUGA) with reference LVEFs from cardiovascular magnetic resonance (CMR) in consecutive patients with cancer.

METHODS

In a cross-sectional study, we compared MUGA clinical and CMR reference LVEFs in 75 patients with cancer who had both studies within 30 days. Misclassification was assessed using the two most common thresholds of LVEF used in cardiotoxicity clinical studies and practice: 50 and 55%.

RESULTS

Compared to CMR reference LVEFs, MUGA clinical LVEFs were only lower by a mean of 1.5% (48.5% vs. 50.0%, p = 0.17). However, the limits of agreement between MUGA clinical and CMR reference LVEFs were wide at -19.4 to 16.5%. At LVEF thresholds of 50 and 55%, there was misclassification of 35 and 20% of cancer patients, respectively.

CONCLUSIONS

MUGA clinical LVEFs are only modestly accurate when compared with CMR reference LVEFs. These data have significant implications on clinical research and patient care of a population with, or at risk for, cardiotoxicity.

Assessment of late anthracycline-induced cardiotoxicity by 123I-mIBG cardiac scintigraphy in patients treated during childhood and adolescence

PURPOSE

The goal of this study was to evaluate late cardiotoxic effects of anthracyclines (ATC) by evaluating cardiac sympathetic activity in a cohort of asymptomatic patients previously treated with ATC for childhood cancers.

METHODS

We studied 89 asymptomatic patients previously treated with ATC with a normal echocardiogram (49 men and 40 women) and a control group of 40 healthy individuals (26 men and 14 women). Both groups underwent planar myocardial 123I-meta-iodobenzylguanidine scintigraphy (123I-mIBG). From these images, the early and late heart-to-mediastinum (H/M) ratio and washout rate (WR) were assessed.

RESULTS

The mean survival at the time of the 123I-mIBG scintigraphy was 5.3 ± 3.4 years. Patients treated with ATC had a lower but clinical normal left ventricular ejection fraction (LVEF) compared to controls (60.44 ± 6.5 vs 64.1 ± 6.0%, P < 0.01). Both the late H/M ratio and WR were not able to discriminate ATC treated patients from controls. The cumulative ATC dose was the only independent predictor of the LVEF, explaining approximately 12% of the variation in LVEF (P = 0.01).

CONCLUSIONS

Although the pathophysiology behind ATC cardiotoxicity is most likely multifactorial, myocardial sympathetic activity is not associated with a reduction in LVEF 5-years after completion of chemotherapy.

Biomarkers for monitoring chemotherapy-induced cardiotoxicity

Cardiotoxicity, including acute and late-onset cardiotoxicity, is a well-known adverse effect of many types of antitumor agents. Early identification of patients with cardiotoxicity is important to ensure prompt treatment and minimize toxic effects. The etiology of chemotherapy-induced cardiotoxicity is multifactorial. Traditional methods for assessment of chemotherapy-induced cardiotoxicity typically involve serial measurements of cardiac function via multi-modality imaging techniques. Typically, however, significant left ventricular dysfunction has already occurred when cardiotoxicity is detected by imaging techniques. Biomarkers, most importantly cardiac natriuretic peptides and troponins, are promising markers for identifying patients potentially at risk for clinical heart failure symptoms. This review summarizes the recent progress in clinical utilization of biomarkers for early diagnosis of acute cardiotoxicity and for prediction of late-onset cardiotoxicity. We also discuss the conflicting results of different studies and the association of results with study design.

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.

The role and clinical effectiveness of multimodality imaging in the management of cardiac complications of cancer and cancer therapy

With the increasing number of individuals living with a current or prior diagnosis of cancer, it is important for the cardiovascular specialist to recognize the various complications of cancer and its therapy on the cardiovascular system. This is true not only for established cancer therapies, such as anthracyclines, that have well established cardiovascular toxicities, but also for the new targeted therapies that can have "off target" effects in the heart and vessels. The purpose of this informational statement is to provide cardiologists, cardiac imaging specialists, cardio-oncologists, and oncologists an understanding of how multimodality imaging may be used in the diagnosis and management of the cardiovascular complications of cancer therapy. In addition, this document is meant to provide useful general information concerning the cardiovascular complications of cancer and cancer therapy as well as established recommendations for the monitoring of specific cardiotoxic therapies.

Does diastolic dysfunction precede systolic dysfunction in trastuzumab-induced cardiotoxicity? Assessment with multigated radionuclide angiography (MUGA)

BACKGROUND

Trastuzumab is successfully used for the treatment of HER2-positive breast cancer. Because of its association with cardiotoxicity, LVEF is monitored by MUGA, though this is a relatively late measure of cardiac function. Diastolic dysfunction (DD) is believed to be an early predictor of cardiac impairment. We evaluate the merit of MUGA-derived diastolic function parameters in the early detection of trastuzumab-induced cardiotoxicity (TIC).

METHODS AND RESULTS

77 trastuzumab-treated patients with normal baseline systolic and diastolic function were retrospectively selected (n = 77). All serial MUGA examinations were re-analyzed for systolic and diastolic function parameters. 36 patients (47%) developed SD and 45 patients (58%) DD during treatment. Both systolic and diastolic parameters significantly decreased. Of the patients with SD, 24 (67%) also developed DD. DD developed prior to systolic impairment in 54% of cases, in 42% vice versa, while time to occurrence did not differ significantly (P = .52). This also applied to the subgroup of advanced stage breast cancer patients (P = .1).

CONCLUSIONS

Trastzumab-induced SD and DD can be detected by MUGA. An impairment of MUGA-derived diastolic parameters does not occur prior to SD and therefore cannot be used as earlier predictors of TIC.

MUGA image artefacts caused by metallic injection ports in breast reconstruction tissue expanders: a report of two breast cancer patients

Expander-based breast reconstruction is a popular form of post-mastectomy reconstruction and involves the temporary subcutaneous implantation of breast tissue expanders that require periodic, incremental inflation with sterile saline by injection until the desired amount of tissue is developed. One type of tissue expander injection port system currently on the market is made of titanium and rare-earth magnets that enhance injection accuracy. These highly dense metallic materials, however, can cause attenuation artefacts on multiple gated acquisition cardiac studies. In this report, we present the cases of two breast cancer patients with artefacts on multiple gated acquisition scans, characteristic of these tissue breast expanders.

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.

Pitfalls and Limitations of SPECT, PET, and Therapeutic Radiopharmaceuticals

Radiopharmaceuticals are widely accepted to be a very safe class of drugs, with very few adverse reactions and unexpected biodistributions. However, problems can arise because of technical issues in manufacture or reconstitution, patient preparation, or drug administration. This review presents highlights of issues that have arisen in the newer classes of radiopharmaceuticals in the last 20 years and expands the scope of the previous report to include PET and therapeutic radiopharmaceuticals. Variations in the "quality" of the eluate of a (99)Mo/(99m)Tc generator remain a major issue. Several of the newer (99m)Tc tracers require a heating step in preparation that can also lead to unacceptably low radiochemical purity. Radiolytic breakdown can be a problem with all classes of radiopharmaceuticals. Many of the newer radiopharmaceuticals localize by receptor- or transporter-mediated processes and thus can be affected by other drugs, making patient preparation more important than ever. Therapeutic radiopharmaceuticals may require coadministration of radioprotectant regimens, such as the use of lysine-arginine infusions with radiopeptide therapy. Extravasation can have serious consequences with therapeutic radiopharmaceuticals. Adverse reactions to newer radiopharmaceuticals remain rare, though may increase because of coadministration of agents such as contrast media. However, there is known to be underreporting of minor adverse reactions. Knowledge of the pitfalls that can occur with radiopharmaceuticals is important in the interpretation of nuclear medicine images and optimal patient care.

Cardiotoxicity due to chemotherapy: role of cardiac imaging

The identification of patients at risk of cardiac toxicity (cardiotoxicity) from cancer therapy is challenging. There is an increasing focus on early detection of cardiotoxicity such that interventions can be instituted to prevent advanced heart failure. Clinical risk prediction tools are limited and clinical symptoms are not specific. Direct assessment of myocardial function before and during cancer treatment using cardiac imaging appears to be an objective method to identify patients at risk. Although, multiple imaging modalities and measures of cardiac function are available, the best modality or the optimal measure of function is unknown. Measurement of left ventricular ejection fraction is most commonly used; however, growing literature suggests that it is inadequate for the detection of early cardiac injury. Other measures include left ventricular diastolic function, myocardial deformation, and myocardial tissue characterization. This review will provide an overview of the clinically available measures for the assessment of cardiotoxicity.

The role of general nuclear medicine in breast cancer

The rising incidence of breast cancer worldwide has prompted many improvements to current care. Routine nuclear medicine is a major contributor to a full gamut of clinical studies such as early lesion detection and stratification; guiding, monitoring, and predicting response to therapy; and monitoring progression, recurrence or metastases. Developments in instrumentation such as the high-resolution dedicated breast device coupled with the diagnostic versatility of conventional cameras have reinserted nuclear medicine as a valuable tool in the broader clinical setting. This review outlines the role of general nuclear medicine, concluding that targeted radiopharmaceuticals and versatile instrumentation position nuclear medicine as a powerful modality for patients with breast cancer.

The role of nuclear imaging in pulmonary hypertension

Pulmonary hypertension (PH) is a disease characterized by a chronic elevation of pulmonary artery pressure from various causes. Pulmonary artery hypertension (PAH) is one of subtype which results in premature death often as a result of right ventricular (RV) dysfunction. In spite of the recent progress in novel cardiac imaging techniques and new drugs for PAH, there remain significant unresolved issues including a need for earlier diagnosis, refinement of risk stratification, and monitoring the effects of treatment. Cardiac and pulmonary imaging with transthoracic echocardiography (TTE) with Doppler, magnetic resonance imaging (MRI), and computed tomography (CT) are done routinely in many clinical centers. However, routine and emerging nuclear techniques may have a pivotal role of assessment of the patient with PH, and is currently the subject of significant research. Potential Roles for Nuclear Imaging in the Evaluation of the PH Patient: (1) Evaluation of cardiac structure and function (RNA) (non-nuclear techniques would include TTE, CT, and MRI). (2) Functional imaging. This includes the use of ventilation-perfusion scintigraphy (V/Q scan) to diagnose chronic thromboembolic pulmonary hypertension (CTEPH), 123l-metaiodobenzylguanidine (MIBG) imaging to evaluate the cardiac sympathetic nervous system (non-nuclear techniques include invasive right heart catheterization and TTE). (3) Measurement of RV perfusion (with gated SPECT studies). (4) Evaluation of cardiac and pulmonary metabolism (PET scans). This review article will summarize the pathophysiology, classification, natural history, and diagnostic approach of PH. Current and emerging nuclear techniques will be discussed under the four themes of evaluation of structure, functional imaging, flow, and metabolism. These will be compared to current and emerging nuclear and non-nuclear diagnostic tests in the evaluation and management of patients with PH. We will also discuss research applications exploring new insights into flow and metabolism in the right heart and lung and the application of new radioligands.

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.

Differential effects of variation in athletes training on myocardial morphophysiological adaptation in men: focus on ¹²³I-MIBG assessed myocardial sympathetic activity

PURPOSE

High intensity systematic physical training leads to myocardial morphophysiological adaptations. The goal of this study was to investigate if differences in training were correlated with differences in cardiac sympathetic activity.

METHODS

58 males (19-47 years), were divided into three groups: strength group (SG), (20 bodybuilders), endurance group (EG), (20 endurance athletes), and a control group (CG) comprising 18 healthy non-athletes. Cardiac sympathetic innervation was assessed by planar myocardial (123)I-metaiodobenzylguanidine scintigraphy using the early and late heart to mediastinal (H/M) ratio, and washout rate (WR).

RESULTS

Left ventricular mass index was significantly higher both in SG (P < .001) and EG (P = .001) compared to CG without a statistical significant difference between SG and EG (P = .417). The relative wall thickness was significantly higher in SG compared to CG (P < .001). Both left ventricular ejection fraction and the peak filling rate showed no significant difference between the groups. Resting heart rate was significantly lower in EG compared to CG (P = .006) and SG (P = .002). The late H/M ratio in CG was significantly higher compared to the late H/M for SG (P = .003) and EG (P = .004). However, WR showed no difference between the groups. There was no significant correlation between the parameters of myocardial sympathetic innervation and parameters of left ventricular function.

CONCLUSIONS

Strength training resulted in a significant increase in cardiac dimensions. Both strength and endurance training seem to cause a reduction in myocardial sympathetic drive. However, myocardial morphological and functional adaptations to training were not correlated with myocardial sympathetic activity.

Outcome prediction in heart failure with atrial fibrillation: relative role of left ventricular ejection fraction and neurohormonal measures

BACKGROUND

Since atrial fibrillation (AF) impacts the measurement and interpretation of left ventricular ejection fraction (LVEF), we hypothesized that the outcome in heart failure (HF) with AF and LVEF ≤ 35% would be more strongly associated with neurohormonal measures than LVEF.

METHODS AND RESULTS

Cardiac adverse events [CAE; HF progression (HFP), life-threatening arrhythmia (ARR), and cardiac death (CD)] and all-cause mortality (ACM) were recorded prospectively in 954 patients with HF and LVEF ≤ 35%: 852 in sinus rhythm (SR) and 102 in AF. Cox proportional hazard models found that the univariate hazard ratios (HR) for LVEF and the first CAE (primary outcome), HFP, ARR, CD, and ACM were significant in SR (0.933, P < .001, 0.933, P < .001, 0.929, P < .001, 0.916, P < .001, 0.945, P = .001, respectively), but not in AF (1.002, P = .95, 1.060, P = .24, 0.922, P = .15, 0.885, P = .09, 0.932, P = .25). HRs for CAEs and ACM and one or more neurohormonal measures (iodine 123 m-iodobenzylguanidine cardiac parameters, B-type natriuretic peptide, and plasma norepinephrine) were significant in SR and AF. The multivariate models for the first CAE and HFP included neurohormonal measures and LVEF in SR and neurohormonal measures in AF.

CONCLUSIONS

In HF with LVEF ≤ 35% with AF, neurohormonal measures, but not LVEF, were related to outcomes.

The prevalence and prognostic significance of right ventricular systolic dysfunction in nonischemic dilated cardiomyopathy

BACKGROUND

Cardiovascular magnetic resonance is the gold-standard technique for the assessment of ventricular function. Although left ventricular volumes and ejection fraction are strong predictors of outcome in dilated cardiomyopathy (DCM), there are limited data regarding the prognostic significance of right ventricular (RV) systolic dysfunction (RVSD). We investigated whether cardiovascular magnetic resonance assessment of RV function has prognostic value in DCM.

METHODS AND RESULTS

We prospectively studied 250 consecutive DCM patients with the use of cardiovascular magnetic resonance. RVSD, defined by RV ejection fraction≤45%, was present in 86 (34%) patients. During a median follow-up period of 6.8 years, there were 52 deaths, and 7 patients underwent cardiac transplantation. The primary end point of all-cause mortality or cardiac transplantation was reached by 42 of 86 patients with RVSD and 17 of 164 patients without RVSD (49% versus 10%; hazard ratio, 5.90; 95% confidence interval [CI], 3.35-10.37; P<0.001). On multivariable analysis, RVSD remained a significant independent predictor of the primary end point (hazard ratio, 3.90; 95% CI, 2.16-7.04; P<0.001), as well as secondary outcomes of cardiovascular mortality or cardiac transplantation (hazard ratio, 3.35; 95% CI, 1.76-6.39; P<0.001), and heart failure death, heart failure hospitalization, or cardiac transplantation (hazard ratio, 2.70; 95% CI, 1.32-5.51; P=0.006). Assessment of RVSD improved risk stratification for all-cause mortality or cardiac transplantation (net reclassification improvement, 0.31; 95% CI 0.10-0.53; P=0.001).

CONCLUSIONS

RVSD is a powerful, independent predictor of transplant-free survival and adverse heart failure outcomes in DCM. Cardiovascular magnetic resonance assessment of RV function is important in the evaluation and risk stratification of DCM patients.

Planar radionuclide angiography with a dedicated cardiac SPECT camera

BACKGROUND

We compared a dedicated cardiac camera with a traditional system for left ventricular (LV) functional measurements using gated blood-pool imaging.

METHODS

24-frame gated planar images were obtained from 48 patients in an LAO orientation for 6M counts/view on a standard gamma camera. Immediately thereafter, 24-frame ECG-gated data were obtained for 8 minutes on a dedicated cardiac SPECT camera. The gated SPECT image volumes were iteratively reconstructed and then transferred offline. In-house software was used to reproject the images into a 24-frame gated planar format. Both the original and the reprojected gated planar datasets were analyzed using semiautomated software to determine ejection fraction (EF), ventricular volume (end diastolic volume, EDV), peak ejection rate (PER), and peak filling rate (PFR).

RESULTS

The difference in EF values averaged 0.4% ± 4.4%. The correlation in EF was r ≥ 0.94 (P < .01) with a linear regression slope of 0.98. Correlation of the EDV was r ≥ 0.86 (P < .01), but the volumes from the dedicated cardiac camera were smaller (linear regression slope was 0.6). Correlation of PFR and PER were r = 0.91 and r ≥ 0.83, respectively (P < .01 for both).

CONCLUSIONS

Reprojection of 24-frame gated blood-pool SPECT images is an effective means of obtaining LV functional measurements with a dedicated cardiac SPECT camera using standard 2D-planar analysis tools.

Prediction of anthracycline cardiotoxicity after chemotherapy by biomarkers kinetic analysis

Anthracyclines are active drugs against breast cancer, but can exert cardiotoxic effects. We analyzed the association between the kinetics of various biomarkers during chemotherapy, and the risk of subsequent cardiac toxicity. 50 patients (49 women) with early breast cancer surgically treated and eligible to anthracycline-based adjuvant chemotherapy were analyzed. The left ventricular ejection fraction (LVEF) together with the plasma concentration of several blood markers was measured at the beginning of anthracycline chemotherapy (t (0)), 5 months (t (1)), 16 months (t (2)), 28 months (t (3)), and 40 months later (t (4)). A single measured LVEF value less than 50% or a clinically overt congestive heart failure (CHF) was considered cardiotoxic effects. We tested whether the kinetics of LVEF and blood biomarkers measured during chemotherapy was predictive of subsequent cardiotoxicity and overall cardiac fitness. The left ventricular ejection fraction measured at the end of treatment as well as the rate of change of hemoglobin concentration during anthracycline-based chemotherapy predicted cardiotoxicity in a 3-year follow-up period. When LVEF at the end of chemotherapy was lower than 53% or hemoglobin blood concentration declined more than 0.33 g/dL/month during chemotherapy, the odds ratio of subsequent cardiotoxicity was 37.3 and 18, respectively. The specificity of these two tests was 93.3% and 80%, whereas the sensitivity was 90.9 and 81.2%, respectively. Testing the rate of change of hemoglobin concentration during anthracycline-based chemotherapy, as well as the left ventricular ejection fraction at the end of treatment, seems a powerful method to assess the effects of anthracyclines on cardiac fitness and identify patients at high risk of CHF. Further validation of these tests on a large cohort of patients and cost-benefit analysis should be encouraged.

Novel techniques for assessment of left ventricular systolic function

The evaluation of left ventricular systolic function is one of the most common reasons for referral for a non-invasive cardiac imaging study. In addition to its diagnostic and prognostic value, an assessment of ejection fraction can also be used to guide medical and device therapy. Thus, obtaining an accurate and reproducible assessment of LVEF is essential for patient management. This review will focus on novel multi-modality techniques used for the quantification of left ventricular systolic function. Emerging echocardiography techniques such as three-dimensional echocardiography and strain imaging and their incremental role over traditional 2D imaging will be discussed. In addition, new developments expanding nuclear imaging techniques' evaluation of left ventricular systolic function will be reviewed. Finally, an overview of advances in imaging techniques such as cardiac magnetic resonance and cardiac computed tomography, which now allow for an accurate and highly reproducible assessment of LVEF, will be presented.

Role of three-dimensional echocardiography in breast cancer: comparison with two-dimensional echocardiography, multiple-gated acquisition scans, and cardiac magnetic resonance imaging

PURPOSE

In patients with breast cancer, the administration of doxorubicin and trastuzumab is associated with an increased risk of cardiotoxicity. Although multiple-gated acquisition (MUGA) scans and two-dimensional transthoracic echocardiography (TTE) are conventional methods for baseline and serial assessment of left ventricular ejection fraction (LVEF) in these patients, little is known about the use of real-time three-dimensional TTE (RT3D TTE) in this clinical setting. The aim of this study was to assess the accuracy of MUGA, 2D TTE, and RT3D TTE for determining LVEF in comparison to cardiac magnetic resonance imaging (CMR).

METHODS

Between 2007 and 2009 inclusive, 50 female patients with human epidermal growth factor receptor 2-positive breast cancer received adjuvant trastuzumab after doxorubicin. Serial MUGA, 2D TTE, RT3D TTE, and CMR were performed at baseline, 6, and 12 months after the initiation of trastuzumab.

RESULTS

A comparison of left ventricular end diastolic volume (LVEDV) demonstrated a modest correlation between 2D TTE and CMR (r = 0.64 at baseline; r = 0.69 at 12 months, respectively). A comparison of LVEDV between RT3D TTE and CMR demonstrated a stronger correlation (r = 0.87 at baseline; r = 0.95 at 12 months, respectively). Although 2D TTE demonstrated a weak correlation with CMR for LVEF assessment (r = 0.31 at baseline, r = 0.42 at 12 months, respectively), both RT3D TTE and MUGA showed a strong correlation when compared with CMR (r = 0.91 at baseline; r = 0.90 at 12 months, respectively).

CONCLUSION

As compared with conventional MUGA, RT3D TTE is a feasible, accurate, and reproducible alternate imaging modality for the serial monitoring of LVEF in patients with breast cancer.