Multigated Radionuclide Angiography Research Articles

LVEF by Multigated Acquisition Scan Compared to Other Imaging Modalities in Cardio-Oncology: a Systematic Review.

Purpose of ReviewThe prevalence of cancer therapy-related cardiac dysfunction (CTRCD) is increasing due to improved cancer survival. Serial monitoring of cardiac function is essential to detect CTRCD, guiding timely intervention strategies. Multigated radionuclide angiography (MUGA) has been the main screening tool using left ventricular ejection fraction (LVEF) to monitor cardiac dysfunction. However, transthoracic echocardiography (TTE) and cardiac magnetic resonance imaging (CMR) may be more suitable for serial assessment. We aimed to assess the concordance between different non-radiating imaging modalities with MUGA to determine whether they can be used interchangeably.Recent FindingsIn order to identify relevant studies, a PubMed search was performed. We included cross-sectional studies comparing MUGA LVEF to that of 2D TTE, 3D TTE, and CMR. From 470 articles, 22 were selected, comprising 1017 patients in total. Among others, this included three 3D TTE, seven 2D harmonic TTE + contrast (2DHC), and seven CMR comparisons. The correlations and Bland-Altman limits of agreement varied for CMR but were stronger for 3D TTE and 2DHC.SummaryOur findings suggest that MUGA and CMR should not be used interchangeably whereas 3D TTE and 2DHC are appropriate alternatives following an initial MUGA scan. We propose a multimodality diagnostic imaging strategy for LVEF monitoring in patients undergoing cancer treatment.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11897-022-00544-3.

Right ventricular functional analysis utilizing first pass radionuclide angiography for pre-operative ventricular assist device planning: a multi-modality comparison

BackgroundAdvanced heart failure treated with a left ventricular assist device is associated with a higher risk of right heart failure. Many advanced heart failures patients are treated with an ICD, a relative contraindication to MRI, prior to assist device placement. Given this limitation, left and right ventricular function for patients with an ICD is calculated using radionuclide angiography utilizing planar multigated acquisition (MUGA) and first pass radionuclide angiography (FPRNA), respectively. Given the availability of MRI protocols that can accommodate patients with ICDs, we have correlated the findings of ventricular functional analysis using radionuclide angiography to cardiac MRI, the reference standard for ventricle function calculation, to directly correlate calculated ejection fractions between these modalities, and to also assess agreement between available echocardiographic and hemodynamic parameters of right ventricular function.MethodsA retrospective review from January 2012 through May 2014 was performed to identify advanced heart failure patients who underwent both cardiac MRI and radionuclide angiography for ventricular functional analysis. Nine heart failure patients (8 men, 1 woman; mean age of 57.0 years) were identified. The average time between the cardiac MRI and radionuclide angiography exams was 38.9 days (range: 1 - 119 days). All patients undergoing cardiac MRI were scanned using an institutionally approved protocol for ICD with no device-related complications identified. A retrospective chart review of each patient for cardiomyopathy diagnosis, clinical follow-up, and echocardiogram and right heart catheterization performed during evaluation was also performed.ResultsThe 9 patients demonstrated a mean left ventricular ejection fraction (LVEF) using cardiac MRI of 20.7% (12 – 40%). Mean LVEF using MUGA was 22.6% (12 – 49%). The mean right ventricular ejection fraction (RVEF) utilizing cardiac MRI was 28.3% (16 – 43%), and the mean RVEF calculated by FPRNA was 32.6% (9 – 56%). The mean discrepancy for LVEF between cardiac MRI and MUGA was 4.1% (0 – 9%), and correlation of calculated LVEF using cardiac MRI and MUGA demonstrated an R of 0.9. The mean discrepancy for RVEF between cardiac MRI and FPRNA was 12.0% (range: 2 – 24%) with a moderate correlation (R = 0.5). The increased discrepancies for RV analysis were statistically significant using an unpaired t-test (t = 3.19, p = 0.0061). Echocardiogram parameters of RV function, including TAPSE and FAC, were for available for all 9 patients and agreement with cardiac MRI demonstrated a kappa statistic for TAPSE of 0.39 (95% CI of 0.06 – 0.72) and for FAC of 0.64 (95% of 0.21 – 1.00).ConclusionHeart failure patients are increasingly requiring left ventricular assist device placement; however, definitive evaluation of biventricular function is required due to the increased mortality rate associated with right heart failure after assist device placement. Our results suggest that FPRNA only has a moderate correlation with reference standard RVEFs calculated using cardiac MRI, which was similar to calculated agreements between cardiac MRI and echocardiographic parameters of right ventricular function. Given the need for identification of patients at risk for right heart failure, further studies are warranted to determine a more accurate estimate of RVEF for heart failure patients during pre-operative ventricular assist device planning.

Early anthracycline-induced cardiotoxicity monitored by echocardiographic Doppler parameters combined with serum hs-cTnT.

As growing numbers of long-term cancer survivors faced with the cardiac side effects by anthracycline treatment, it is necessary to explore the optimal monitoring method for the early detection of cardiac toxicity. We conducted a retrospective analysis of 82 consecutive patients with diffuse large B-cell lymphoma treated with chemotherapy. Echocardiographic Doppler imaging-derived Tei index and mitral annular peak systolic velocity (Sm) measured by tissue Doppler imaging TDI, serum high-sensitivity cardiac troponin T (hs-cTnT) levels, and left ventricular ejection fraction (LVEF) by multigated radionuclide angiography (MUGA) were obtained before, after 2-4, and after 6-8 chemotherapy cycles. Cardiotoxicity was defined as a relative reduction of LVEF ≥10% from the baseline or LVEF <50% as measured by MUGA. Following chemotherapy, 24 (29.3%) patients developed detectable cardiac abnormality during the treatment. Five (6.1%) patients' cardiac function changed from normal baseline LVEF to <50% after the chemotherapy. Echocardiographic pulse wave Doppler Tei index (PW Tei index) (baseline 0.347±0.115 vs 2-4 cycles 0.459±0.161 vs 6-8 cycles 0.424±0.139, P=.000) inversely correlated with systolic (P<.001) and diastolic dysfunction (P<.001). Serum hs-cTnT levels increased significantly following chemotherapy after 2-4 cycles of chemotherapy with anthracycline. The increase in PW Tei index of 0.095 [sensitivity, 69.2%; specificity, 64.5%; area under the curve (AUC)=0.697; P=.005] and the Sm<13.65cm/s (sensitivity, 66.7%; specificity, 71%; AUC=0.682; P=.009) combined with elevation of serum hs-cTnT level of 0.0075ng/mL (sensitivity, 69.2%; specificity, 83.9%; AUC=0.790; P<.001) after 2-4 chemotherapy cycles from the baseline values can reliably predict cardiotoxicity. We demonstrated that echocardiographic PW Doppler-derived Tei index, and TDI-derived Sm, combined with serum hs-cTnT level can be obtained in outpatient settings to monitor early cardiac toxicity induced by anthracycline therapy.

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

BackgroundTrastuzumab 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 Results77 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). ConclusionsTrastzumab-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.

Nuclear imaging in detection and monitoring of cardiotoxicity.

Cardiotoxicity as a result of cancer treatment is a novel and serious public health issue that has a significant impact on a cancer patient's management and outcome. The coexistence of cancer and cardiac disease in the same patient is more common because of aging population and improvements in the efficacy of antitumor agents. Left ventricular dysfunction is the most typical manifestation and can lead to heart failure. Left ventricular ejection fraction measurement by echocardiography and multigated radionuclide angiography is the most common diagnostic approach to detect cardiac damage, but it identifies a late manifestation of myocardial injury. Early non-invasive imaging techniques are needed for the diagnosis and monitoring of cardiotoxic effects. Although echocardiography and cardiac magnetic resonance are the most commonly used imaging techniques for cardiotoxicity assessment, greater attention is focused on new nuclear cardiologic techniques, which can identify high-risk patients in the early stage and visualize the pathophysiologic process at the tissue level before clinical manifestation. The aim of this review is to summarize the role of nuclear imaging techniques in the non-invasive detection of myocardial damage related to antineoplastic therapy at the reversible stage, focusing on the current role and future perspectives of nuclear imaging techniques and molecular radiotracers in detection and monitoring of cardiotoxicity.

Scintigraphic Techniques for Early Detection of Cancer Treatment–Induced Cardiotoxicity

New antitumor agents have resulted in significant survival benefits for cancer patients. However, several agents may have serious cardiovascular side effects. Left ventricular ejection fraction measurement by (99m)Tc multigated radionuclide angiography is regarded as the gold standard to measure cardiotoxicity in adult patients. It identifies left ventricular dysfunction with high reproducibility and low interobserver variability. A decrease in left ventricular ejection fraction, however, is a relatively late manifestation of myocardial damage. Nuclear cardiologic techniques that visualize pathophysiologic processes at the tissue level could detect myocardial injury at an earlier stage. These techniques may give the opportunity for timely intervention to prevent further damage and could provide insights into the mechanisms and pathophysiology of cardiotoxicity caused by anticancer agents. This review provides an overview of past, current, and promising newly developed radiopharmaceuticals and describes the role and recent advances of scintigraphic techniques to measure cardiotoxicity. Both first-order functional imaging techniques (visualizing mechanical [pump] function), such as (99m)Tc multigated radionuclide angiography and (99m)Tc gated blood-pool SPECT, and third-order functional imaging techniques (visualizing pathophysiologic and neurophysiologic processes at the tissue level) are discussed. Third-order functional imaging techniques comprise (123)I-metaiodobenzylguanidine scintigraphy, which images the efferent sympathetic nervous innervations; sympathetic neuronal PET, with its wide range of tracers; (111)In-antimyosin, which is a specific marker for myocardial cell injury and necrosis; (99m)Tc-annexin V scintigraphy, which visualizes apoptosis and cell death; fatty-acid-use scintigraphy, which visualizes the storage of free fatty acids in the lipid pool of the cytosol (which can be impaired by cardiotoxic agents); and (111)In-trastuzumab imaging, to study trastuzumab targeting to the myocardium. To define the prognostic importance and clinical value of each of these functional imaging techniques, prospective clinical trials are warranted.

Dose-dense adjuvant Doxorubicin and cyclophosphamide is not associated with frequent short-term changes in left ventricular ejection fraction.

Doxorubicin and cyclophosphamide (AC) every 3 weeks has been associated with frequent asymptomatic declines in left ventricular ejection fraction (LVEF). Dose-dense (dd) AC followed by paclitaxel (P) is superior to the same regimen given every third week. Herein, we report the early cardiac safety of three sequential studies of ddAC alone or with bevacizumab (B). Patients with HER2-positive breast cancer were treated on two trials: ddAC followed by P and trastuzumab (T) and ddAC followed by PT and lapatinib. Patients with HER2-normal breast cancer were treated with B and ddAC followed by B and nanoparticle albumin-bound P. Prospective LVEF measurement by multigated radionuclide angiography scan before and after every 2 week AC for 4 cycles and at month 6 from all three trials were aggregated to determine the early risks of cardiac dysfunction. From January 2005 to May 2008, 245 patients were enrolled. The median age was 47 years (range, 27 to 75 years). Median LVEF pre-ddAC was 68% (range, 52% to 82%). LVEF post-ddAC was available in 241 patients (98%) and the median was unchanged at 68% (range, 47% to 81%). Per protocol no patients were ineligible for subsequent targeted biologic therapy based on LVEF decline post-ddAC. In addition, LVEF was available in 222 patients (92%) at 6 months, at which time the median LVEF was similar at 65% (range, 24% to 80%). Within 6 months of initiating chemotherapy, three patients (1.2%; 95% CI, 0.25% to 3.54%) developed CHF, all of whom received T. Dose-dense AC with or without concurrent bevacizumab is not associated with frequent acute or short-term declines in LVEF.

Attenuation corrected gated SPECT for the assessment of left ventricular ejection fraction and volumes

The aim of this study was to evaluate the value of attenuation correction (AC) of Tc-99m tetrofosmin single-photon emission tomography (SPECT) imaging for the assessment of left ventricular ejection fraction (LVEF). Attenuation corrected and non-attenuation corrected (NC) resting Tc-99m tetrofosmin SPECT were compared for the assessment of LVEF. Planar multigated radionuclide angiography (MUGA) served as the reference for LVEF assessment. Patients (n = 56) with left ventricular dysfunction who underwent MUGA and rest gated Tc-99m tetrofosmin SPECT within 1 month were included. The average LVEF on NC gated SPECT was 37.4 +/- 11.8% and on AC SPECT 38.5 +/- 13.4% (P = NS). The absolute mean difference of the LVEF between the MUGA and NC gated SPECT and AC gated SPECT was -0.2% (95% CI -1.7 to 1.3) and -1.3% (95% CI -2.7 to 0.03), respectively (P = NS both vs. MUGA). The correlation between NC gated SPECT and AC gated SPECT versus MUGA measurement was high with a correlation coefficient of 0.89 (P < 0.01) and 0.92 (P < 0.01), respectively. End-diastolic volumes (EDVs) and end-systolic volumes (ESVs) were significantly higher with AC gated SPECT when compared with NC gated SPECT (both P < 0.001). Profile AC gated Tc-99m tetrofosmin SPECT agrees well with MUGA and NC gated Tc-99m tetrofosmin SPECT for the assessment of LVEF. EDVs and ESVs are significantly higher with AC gated SPECT when compared with NC gated SPECT.

Left Ventricular Structure and Function for Postmyocardial Infarction and Heart Failure Risk Stratification by Three-dimensional Echocardiography

Accurate risk stratification by left ventricular (LV) ejection fraction (EF) is essential for treatment of patients with myocardial infarction (MI) or those with heart failure (CHF), because of its high prognostic value.1 This would permit aggressive targeting of therapy in these populations, in whom morbidity and mortality are high. Cardiac magnetic resonance (CMR) and computed tomography (CT) are expensive, not widely available, and impractical for following up large numbers of patients.2,3 Cardiac catheterization (CATH) and multigated radionuclide angiography (MUGA) are either invasive or require use of radioactive tracers.

Updated cardiac safety results of dose-dense (DD) doxorubicin and cyclophosphamide (AC) followed by paclitaxel (T) with trastuzumab (H) in HER2/neu overexpressed/amplified breast cancer (BCA)

582 Background: DD q 2 weekly (w) AC → T is superior to conventionally scheduled (cs) AC → T and safe w/long follow-up (Hudis et al, SABCS 2005). With q 3 wk AC, adjuvant (adj) H is safe and effective (Romond et al and Perez et al, NEJM 2005). We therefore tested DD q 2 w AC → T + H × 1 year (y) as adj treatment (Rx) of patients (pts) with HER2/neu (+) BCA to determine cardiac safety. Based on the reported cardiac event (CE) rate of ≤ 4% in the randomized trials using cs chemotherapy (CRx) + H, we evaluated DD q 2 w AC → T + H with a 1° endpoint of cardiac safety defined as discontinuation (DC) of H due to 1) cardiac death or 2) congestive heart failure (CHF). The 2° endpoint is time to recurrence and overall survival. Methods: Pts with HER2/Neu IHC 3+ or FISH-amplified BCA were enrolled, regardless of tumor size or nodal status. Rx consisted of AC at 60/600 mg/m2 × 4 → T at 175 mg/m2 × 4 q 2 w w/pegfilgrastim 6 mg on d 2 + H × 1 y. Multi-gated radionuclide angiography scan (MUGA) is obtained at baseline and at months (mo) 2 (after AC × 4), 6 (after T × 4), 9, and 18. Pts w/baseline LVEF of ≥ 55% and w/o cardiac illnesses are eligible. Pts w/significant (sig) asymptomatic (asx) LVEF ↓ after DD AC based on mo 2 MUGA did not receive H, and pts w/sig asx LVEF ↓ during H had it DC’d. If the CE rate is &gt; 4%, Rx is deemed not feasible. Results: From January 4, 2005 to November 1, 2005, 70 pts were enrolled. Median (med) age is 49 years (range, 27–72). Forty one of 70 pts (60%) had node (+) BC and 27/70 pts (40%) had (-) nodes. Med baseline LVEF is 68% (range, 55%-81%). As of January 9, 2005, all pts had mo 2 MUGA after DD AC and there is no sig LVEF ↓ and the med LVEF is 67% (range, 58%-79%). To date 39 pts had mo 6 MUGA w/med LVEF of 66% (range, 56%-75%) and one pt had a sig asx LVEF ↓ from baseline of 74% to 56%; H was DC’d. Twenty-three pts had mo 9 MUGA w/a med LVEF of 64% (range, 57%-69%). One patient had clinical CHF at mo 4 w/EF of 45% and improved sig w/cardiac medications. One had pneumonitis during radiation (RT). One had atrial fibrillation w/pericarditis after completion of RT. Discussion: DD AC → T + H appears to have an acceptable cardiac toxicity profile w/1/70 pts having a CE. Updated cardiac safety data will be presented. [Table: see text]

EVALUATION OF ANTHRACYCLINE-INDUCED EARLY LEFT VENTRICULAR DYSFUNCTION IN CHILDREN WITH CANCER: A Comparative Study with Echocardiography and Multigated Radionuclide Angiography

The study aimed to compare diastolic and systolic dysfunctions detected by echocardiography (ECHO) and multigated radionuclide angiography (MUGA) in patients with cancer in the first 3 months after anthracycline-comprising chemotherapy. Children with leukemia and solid tumors who had anthracycline-comprising chemotherapy were enrolled in the study. ECHO and MUGA were performed in all patients before the first chemotherapy course and in the first 3 month of completing anthracycline-comprising chemotherapy. Cumulative anthracycline doses per body surface were calculated. Left ventricular systolic and diastolic functions were measured by both techniques. Twenty-one patients with a median age of 6.9 ± 3.6 years were enrolled in the study. Mean cumulative anthracycline doses were equivalent to 276 ± 83 mg/m2 doxorubicin. After anthracycline chemotherapy, cardiac dysfunction was detected in 14 and 48% of the patients by ECHO and MUGA, respectively. All dysfunctions detected by ECHO were systolic, whereas 29% of the patients had diastolic and 38% of the patients had systolic dysfunction in MUGA study. Although the study group is small, MUGA seems more sensitive in detecting anthracycline-induced systolic and diastolic cardiac dysfunctions compared to ECHO.

Clinical validation of the gated blood pool SPECT QBS® processing software in congestive heart failure patients: correlation with MUGA, first-pass RNV and 2D-echocardiography

Left (LVEF) and right ventricular ejection fraction (RVEF) as well as LV regional wall motion at rest are valuable tools to monitor and tailor treatment of congestive heart failure (CHF) patients. Gated blood pool SPECT (GBPS) is under evaluation as an "all-in-one" technique, providing information on LVEF, RVEF, and wall motion derived from a single examination. Aim of the study was to evaluate a commercially available automated GBPS processing software for EF measurements and wall motion analysis in heart failure patients. Thirty-two patients (12 female; mean age+/-SD: 53+/-13 years), suffering from dilated (63%), ischemic (25%) or hypertrophic (13%) cardiomyopathy, were studied. First-pass radionuclide ventriculography (FP-RNV), planar multigated radionuclide angiography (MUGA), and GBPS were performed at rest after in vivo labeling of red blood cells, and LVEF and RVEF was calculated with each method. Later on the same day LVEF was calculated by echocardiography. LV wall motion (summed motion score and wall motion index) was derived from GBPS and echocardiography using the standard 16-segment model. Mean LVEF measured by GBPS, echocardiography, MUGA and FP-RNV was 33+/-13%, 37+/-15%, 41+/-14% and 45+/-13%, respectively. LVEF values calculated from GBPS showed moderate to good correlation with FP-RNV (r=0.61), MUGA (r=0.65) and ECHO (r=0.74; all p<0.01). Mean RVEF calculated by GBPS, FP-RNV and MUGA was 45+/-14%, 46+/-9% and 38+/-9%, respectively. RVEF values calculated from GBPS showed weak correlation with FP-RNV (r=0.33) and MUGA (r=0.26; all p=n.s.). Assessment of GBPS wall motion was qualitatively possible in all patients. The agreement between GBPS and ECHO was 82% (kappa=0.73). The wall motion index showed good correlation between both methods (r=0.88; p<0.001). An automated algorithm for LVEF calculation and wall motion analysis using GBPS is feasible for clinical routine diagnostic in CHF patients. The RVEF calculation method needs to be improved before routine clinical application can be recommended.

The validation of volumetric real-time 3-dimensional echocardiography for the determination of left ventricular function

The objective of this study was to validate a real-time 3-dimensional echocardiography (3DE) technique for the determination of left ventricular (LV) volume and ejection fraction (EF). In 10 mongrel dogs, an electromagnetic flow (EMF) probe was placed on the aorta, and the thorax was closed. Transthoracic imaging was performed during multiple hemodynamic conditions (n = 58) with simultaneous measurement of stroke volume (SV) with the use of EMF. From the volumetric data set, LV volumes were manually traced off-line by 2 independent observers with an apical rotation method (6 planes) and a conventional method (biplane) in a subset of conditions. This tracing technique was also evaluated in 18 human subjects in whom the calculated EF values were compared with values derived by multigated radionuclide angiography (MUGA). Excellent correlation and close limits of agreement were noted between SV measured by 3DE and EMF (r = 0.93) in dogs. In comparison with EMF-derived SV, 3DE provided better correlation than the biplane method (r = 0.93 versus r = 0.61). Interobserver and intraobserver variabilities were comparable (r = 0.94 and r = 0.94, respectively). In a comparison of MUGA-derived EF values and those obtained by 3DE in human subjects, 3DE provided better correlation than the biplane method (r = 0.94 versus r = 0.85). Real-time 3DE accurately measures left ventricular volumes transthoracically over a wide range of hemodynamic conditions in dogs and accurately determines EF in humans.

Assessment of left ventricular function by real-time 3-dimensional echocardiography compared with conventional noninvasive methods

Quantitative assessment of left ventricular ejection fraction is an essential component of cardiac evaluation. We performed real-time 3-dimensional echocardiography in 56 consecutive patients who underwent multigated radionuclide angiography. Thirteen patients were excluded for the following reasons: 5 for large size of left ventricle required for image acquisition, 5 for suboptimal image quality in real-time 3-dimensional echocardiography, and 3 for atrial fibrillation. Finally, we compared left ventricular ejection fraction assessed by real-time 3-dimensional echocardiography and conventional 2-dimensional echocardiography with that obtained by multigated radionuclide angiography in 43 patients. Left ventricular ejection fraction was determined by real-time 3-dimensional echocardiography with the use of parallel plane-disks and sector plane-disks summation methods. A good correlation was obtained between both real-time 3-dimensional echocardiography methods and multigated radionuclide angiography (r = 0.87 and 0.90, standard error of estimate = 3.7% and 4.2%), whereas the relation between the 2-dimensional echocardiography method and radionuclide angiography demonstrated a significant departure from the line of identity (P <.001). In addition, interobserver variability was significantly lower (P <.05) for the real-time 3-dimensional echocardiography methods than that by the 2-dimensional echocardiography method. Real-time 3-dimensional echocardiography may be used for quantification of left ventricular function as an alternative to conventional methods in patients with adequate image quality. (J Am Soc Echocardiogr 2001;14:275-84.)

LV diastolic function in patients with heart failure: Assessment by multigated radionuclide angiography and effect of inotropic therapy

LV diastolic function in patients with heart failure: Assessment by multigated radionuclide angiography and effect of inotropic therapy

Enhanced detection of reversible myocardial hypoperfusion by technetium 99m-tetrofosmin imaging and first-pass radionuclide angiography after nitroglycerin administration

Background. Reversal of ischemia after myocardial infarction by revascularization is worthwhile only if viability exists in a sufficiently large portion of the left ventricle. Methods and Results. To determine myocardial hypoperfusion reversibility and its influence on segmental and global function, we studied 50 patients after myocardial infarction. Three technetium 99m-tetrofosmin scintigraphies were performed: 1 at rest, 1 after 0.6 mg sublingual nitroglycerin (NTG), and 1 after injection at peak stress. First-pass multigated radionuclide angiography was obtained at rest and after NTG. Each patient also underwent a stress redistribution-reinjection thallium-201 scintigraphy. During stress 99mTc-tetrofosmin, 104 segments had normal uptake, 51 showed moderately reduced uptake, and 186 had severely reduced uptake. Of these 186 segments, 33 (18%) improved at rest, and 41 (22%) improved only after NTG. Fifty-nine (79%) of these segments with improved uptake were also found to have reversible defects on 201TI imaging. In the 26 patients with ventricular dysfunction, a 73% agreement was found between the functional and 99mTc-tetrofosmin uptake post-NTG improvement, whereas a 69% agreement was found with thallium reinjection. No significant differences were seen between 99mTc-tetrofosmin and 201TI imaging. Conclusion. Nitroglycerin administration during 99mTc-tetrofosmin scintigraphy improves the detection of myocardium with reversible hypoperfusion in patients with a previous myocardial infarction.

Left Ventricular Ejection Fraction in Patients with Normal and Distorted Left Ventricular Shape by Three-Dimensional Echocardiographic Methods: A Comparison with Radionuclide Angiography

Background: Serial evaluation of left ventricular (LV) ejection fraction (EF) is important for the management and follow-up of cardiac patients. Our aim was to compare LVEF calculated from two three-dimensional echocardiographic (3DE) methods with multigated radionuclide angiography (RNA), in patients with normal and abnormally shaped ventricles. Methods and Results: Forty-one consecutive patients referred for RNA underwent precordial rotational 3DE acquisition of 90 cut-planes. From the volumetric data set, LVEF was calculated by (a) Simpson's rule (3DS) through manual endocardial tracing of LV short-axis series at 3 mm slice distance and (b) apical biplane modified Simpson's method (BMS) in 29 patients by manual endocardial tracing of the apical four-chamber view and its computer-derived orthogonal view. Patients included three groups: A, 17 patients with LV segmental wall motion abnormalities; B, 13 patients with LV global hypokinesis; and C, 11 patients with normal LV wall motion. For all the 41 patients, there was excellent correlation, close limits of agreement, and nonsignificant difference between 3DS and RNA for LVEF calculation ( r = 0.99, [-6.7, +6.9] and p = 0.9), respectively. For the 29 patients, excellent correlation and nonsignificant differences between LVEF calculated by both 3DS and BMS and values obtained by RNA were found ( r = 0.99 and 0.97, p = 0.7 and p = 0.5, respectively). In addition, no significant difference existed between values of LVEF obtained from RNA, 3DS, and BMS by the analysis of variance ( p = 0.6). The limits of agreement tended to be closer between 3DS and RNA (-6.8, +7.2) than between BMS and RNA (-8.3, +9.7). The intraobserver and interobserver variability of RNA, 3DS, and BMS for calculating LVEF(%) were (0.8, 1.5), (1.3, 1.8), and (1.6, 2.6), respectively. There were closer limits of agreement between 3DS and RNA for LVEF calculation in A, B, and C patient subgroups [(-3.5, +5), (-8.4, +5.6), and (-7.8, +8.6)] than that between BMS and RNA [(-8.1, +10.7), (-11.9, +9.3), and (-9.1, +11.3)], respectively. Conclusions: No significant difference existed between RNA, 3DS, and BMS for LVEF calculation. 3DS has better correlation and closer limits of agreement than BMS with RNA for LVEF calculation, particularly in patients with segmental wall motion abnormalities and global hypokinesis. 3DS has a comparable observer variability with RNA. Therefore the use of 3DS for serial accurate LVEF calculation in cardiac patients is recommended. (J Am Soc Echocardiogr 1998;11:620-30.)

Cardiac function during iron chelation therapy in adult non-thalassaemic patients with transfusional iron overload.

It is well-documented that iron chelation by desferrioxamine protects/improves the cardiac function in blood transfusion-dependent children suffering from beta-thalassaemia. In patients who do not become dependent upon blood transfusion until adulthood (ANT-patients), iron chelation by desferrioxamine may affect the cardiac function in unknown ways, presumably because age-related changes in the heart may cause iron chelation to affect the cardiac function in different ways. We therefore followed the left ventricular ejection fraction (LVEF) by multigated radionuclide angiography in 16 iron-loaded ANT-patients during iron chelation alone and after increasing the efficacy of chelation by vitamin C supplementation. During 12 months of iron chelation the mean LVEF fell significantly from 63.3% to 58.0% (p=0.04). Individual changes in LVEF did not correlate significantly with age but with the pretreatment liver iron concentration. After initiation of vitamin C supplementation, the mean LVEF increased from 55.9% to 65.3% (p=0.01). Our data suggest that in ANT-patients prolonged desferrioxamine treatment without vitamin C supplementation may be associated with reduced LVEF, whereas vitamin C supplementation seems to benefit the cardiac function. Similar findings have not been described in beta-thalassaemia and may hence be specific for ANT-patients. However, our findings have to be confirmed by controlled studies.

Left ventricular volume calculation automated technique applied to multigated radionuclide angiography

Left ventricular volume calculation automated technique applied to multigated radionuclide angiography

Using mathematical morphology to determine left ventricular contours

The aim of this study is to investigate the use of mathematical morphology for the determination of left ventricular contours in scintigraphic images using multigated radionuclide angiography. We have developed a completely automatic method that first restores the image with a Wiener filter, then finds the region where the left ventricle is contained, and finally segments the left ventricle contour and a background zone. The contours depend on the values of the parameters that appear in the mathematical morphology method, which are related to the height and the slope of the count distribution. Results obtained with this method are compared with the contours and the background zones outlined by experts on the basis of the number of counts. We study the values of the parameters with which the optimum correlation is obtained.