tellurium and technetium-tc-99m-tetrofosmin

Guidelines for SPECT myocardial perfusion imaging (MPI) traditionally recommend a fixed tracer dose. Yet, clinical practice shows degraded image quality in heavier patients. The aim was to optimize and validate the tracer dose and scan time to obtain a constant image quality less dependent on patients' physical characteristics.. 125 patients underwent Cadmium Zinc Telluride (CZT)-SPECT stress MPI using a fixed Tc-99m-tetrofosmin tracer dose. Image quality was scored by three physicians on a 4-point grading scale and related to the number of photon counts normalized to tracer dose and scan time. Counts were correlated with various patient-specific parameters dealing with patient size and weight to find the best predicting parameter. From these data, a formula to provide constant image quality was derived, and subsequently tested in 92 new patients.. Degradation in image quality and photon counts was observed for heavier patients for all patients' specific parameters (P < .01). We found body weight to be the best-predicting parameter for image quality and derived a new dose formula. After applying this new body weight-depended tracer dose and scan time in a new group, image quality was found to be constant (P > .19) in all patients.. Also in CZT SPECT image quality decreases with weight. The use of a tracer dose and scan time that depends linearly on patient's body weight corrected for the varying image quality in CZT-SPECT MPI. This leads to better radiation exposure justification.

Topics: Body Size; Cadmium; Female; Humans; Image Interpretation, Computer-Assisted; Male; Maximum Tolerated Dose; Middle Aged; Myocardial Perfusion Imaging; Observer Variation; Organophosphorus Compounds; Organotechnetium Compounds; Patient Safety; Radiation Dosage; Radiation Protection; Radiopharmaceuticals; Reproducibility of Results; Sensitivity and Specificity; Tellurium; Tomography, Emission-Computed, Single-Photon; Whole-Body Counting; Zinc

The global rest MBF was 0.76 ± 0.19 mL/min/gr by PET and 0.76 ± 0.24 by AC-CZT (P = NS) and 1.14 ± 0.4 by NAC-CZT (P < 0.001 vs PET and AC-CZT). Stress MBF was higher when measured by PET than AC-CZT (1.87 ± 0.45 vs 1.62 ± 0.68 mL/min/gr, P < 0.0008), but lower than NAC-CZT (2.36 ± 1.1, P < 0.0003). The MBF reserve ratio (MFR) was higher by PET than AC-CZT (2.52 ± 0.56 vs 2.22 ± 1 (P < 0.009) and NAC-CZT (2.18 ± 1.0, P < 0.004). Linear regression was better between PET (MFR and stress MBF) and AC-CZT than between PET and NAC-CZT. ROC curve analysis showed the significant ability of AC-CZT to predict MFR < 2 and stress MBF < 1.7 (AUC = 0.75 and 0.82 respectively) and to differentiate between normal and CAD patients (AUC = 0.747 and 0.892 for MFR and stress MBF, respectively).. Our data show a reasonable correlation between MBF and MFR measured by N

Topics: Adult; Aged; Aged, 80 and over; Ammonia; Cadmium; Coronary Artery Disease; Coronary Circulation; Female; Fractional Flow Reserve, Myocardial; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Nitrogen Radioisotopes; Organophosphorus Compounds; Organotechnetium Compounds; Positron Emission Tomography Computed Tomography; Predictive Value of Tests; Radiopharmaceuticals; ROC Curve; Tellurium; Tomography, Emission-Computed, Single-Photon; Zinc

Topics: Cadmium; Fatty Acids; Feasibility Studies; Humans; Iodine Radioisotopes; Iodobenzenes; Myocardial Infarction; Organophosphorus Compounds; Organotechnetium Compounds; Tellurium; Zinc

The applicability of ultra-low-dose computed tomography (CT) for attenuation correction (AC) of single-photon-emission computed tomography myocardial perfusion imaging (SPECT-MPI) remains elusive.. One-hundred patients underwent one-day. Attenuation maps for MPI obtained from ultra-low radiation dose CT scans are interchangeable with attenuation maps from standard-dose CT while offering a substantial reduction in radiation dose exposure.

Topics: Aged; Cadmium; Female; Heart Diseases; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Prospective Studies; Radiation Dosage; Reproducibility of Results; Sensitivity and Specificity; Tellurium; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Zinc

The use of cadmium-zinc-telluride-based scanners may increase the clinical feasibility of simultaneous dual-isotope imaging. In the current study, we sought to investigate a potential acquisition time in simultaneous Tc-tetrofosmin/I-β-methyl-p-iodophenyl pentadecanoic acid dual-isotope imaging using a Discovery NM/CT 670 cadmium-zinc-telluride.. Simultaneous Tc-tetrofosmin/I-β-methyl-p-iodophenyl pentadecanoic acid dual-isotope imaging was performed in 29 patients who had undergone primary percutaneous coronary intervention for acute myocardial infarction. Referenced images with an acquisition time of 65 s/view (16.25 min) were reframed to produce images with acquisition times of 33, 16, and 8 s/view. The values for the quantitative-gated single-photon emission computed tomography (SPECT) and the quantitative perfusion SPECT were compared.. The quantitative-gated SPECT values for images with 33, 16, and 8 s/views showed good consistency with those for 65 s/view (the lower 95% confidence intervals for the intraclass correlation were ≥0.80). The quantitative perfusion SPECT values for Tc-tetrofosmin images with 33, 16, and 8 s/views also showed good consistency with those for 65 s/view; however, the quantitative perfusion SPECT values for I-β-methyl-p-iodophenyl pentadecanoic acid images with an acquisition time of 8 s/view were not consistent with the reference acquisition time of 65 s/view.. The quantitative-gated SPECT and quantitative perfusion SPECT values obtained from images with shorter acquisition times correlated with the values obtained from images with a reference acquisition time of 65 s/view; however, tracer-specific predisposition should be considered. These findings suggest that it is possible to reduce acquisition time when performing simultaneous Tc-tetrofosmin/I-β-methyl-p-iodophenyl pentadecanoic acid dual-tracer imaging with the novel cadmium-zinc-telluride scanner.

Topics: Acute Disease; Cadmium; Fatty Acids; Female; Humans; Image Processing, Computer-Assisted; Iodobenzenes; Male; Middle Aged; Myocardial Infarction; Organophosphorus Compounds; Organotechnetium Compounds; Percutaneous Coronary Intervention; Tellurium; Time Factors; Tomography, Emission-Computed, Single-Photon; Zinc

Left ventricular (LV) ejection fraction (EF) during high dobutamine stress (HD) by real-time gated-SPECT myocardial perfusion imaging (MPI) on a cadmium-zinc-telluride (CZT) gamma camera was validated versus cardiac magnetic resonance imaging (CMR).. After injecting 99mTc-tetrofosmin (320 MBq) in 50 patients (mean age 64 +/- 11 years), EF at rest and post-stress as well as relevant changes in EF at HD (ΔEF ≥ 5%) were assessed. CZT and CMR rest EF values yielded an excellent correlation and agreement (r = 0.96; P < 0.001; Bland-Altman limits of agreement (BA): + 0 to 14.8%). HD EF acquisition was feasible using CZT and correlated better to HD CMR EF than did post-stress CZT EF (r = 0.85 vs 0.76, respectively, all P < 0.001). Agreement in ΔEF detection between HD CMR and immediate post-stress CZT (reflecting standard acquisition using conventional SPECT camera unable to scan during stress) was 45%, while this increased to 85% with real-time HD CZT scan.. Real-time ultrafast dobutamine gated-SPECT MPI with a CZT device is feasible and provides accurate measurements of HD LV performance.

Topics: Aged; Cadmium; Dobutamine; Feasibility Studies; Female; Gamma Cameras; Heart Ventricles; Humans; Magnetic Resonance Imaging; Male; Middle Aged; Movement; Myocardial Contraction; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Reproducibility of Results; Tellurium; Tomography, Emission-Computed, Single-Photon; Ventricular Function, Left; Zinc

We validated a 1-day myocardial perfusion imaging (MPI) protocol using an ultra low-dose(ULD) equal for stress and rest on a cadmium zinc telluride (CZT).. Fifty-six patients underwent a 1-day MPI protocol using a standard (SD) 99mTc-tetrofosmin dose at stress (320 MBq) and rest (960 MBq) with 5 min acquisition time each (SD). Within 2 weeks MPI was repeated using ULD 99mTc-tetrofosmin equal for stress and rest (160 MBq) with 15 min acquisition time each (ULD). All scans were performed on a CZT camera (DNM 570c, GE Healthcare). Background subtraction was applied on the rest MPI of the ULD using P-mod software. Presence and extent of perfusion defect were analysed. Pearson's correlation was used to compare ejection fraction (EF), end diastolic volume (EDV), and end systolic volume (ESV) between both protocols. SD revealed ischaemia in 23, scar in 3, and an equivocal finding in 1 patient, while normal findings were documented in 29 patients. ULD resulted in the following findings: ischaemia 23, scar 3, and 30 normal scans. Congruence of SD and ULD was 22/23 for ischaemia, 3/3 for scar, and 29/29 in normal patients; one patient with ischaemia in SD was classified as scar in ULD. Overall agreement of ULD with SD was 98%. The mean extent of defect was comparable between SD and ULD for the stress (10% vs. 11%, respectively, P = NS) and rest studies (5% vs. 7%, respectively, P = NS). An excellent correlation between SD and ULD was found for EF (r = 0.93), EDV (r = 0.95), and ESV (r = 0.97).. CZT cameras may enable reliable MPI scanning in patients with known or suspected coronary artery disease using protocols with about a factor 4-decrease in radiation dose exposure compared with traditional protocols.

Topics: Aged; Aged, 80 and over; Cadmium; Cardiac-Gated Imaging Techniques; Coronary Artery Disease; Exercise Test; Female; Gamma Cameras; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Prospective Studies; Radiographic Image Interpretation, Computer-Assisted; Radiopharmaceuticals; Rest; Tellurium; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Zinc

We previously validated the use of a data-driven cardiac respiratory-motion (RM) correction method (REGAT) applicable to CZT SPECT myocardial perfusion imaging (MPI). In this study, we adapted the same process used with REGAT for RM to generate data-driven cardiac contraction triggers and corresponding cardiac contraction-gated SPECT studies (GSPECT-DD). We aimed to study its feasibility and compare its performances to GSPECT studies generated with ECG monitor-based triggers (GSPECT-ECG).. We found almost perfect agreement between cardiac contraction triggers generated with data-driven and ECG monitor-based methods. As compared to GSPECT-ECG, GSPECT-DD provided comparable and well-correlated LV global systolic function parameters and similar cine image quality at both stress and rest.. Data-driven cardiac contraction gating using REGAT is feasible with low-dose and high-dose MPI CZT SPECT. It provides GSPECT-DD studies comparable to GSPECT-ECG.

Topics: Aged; Cadmium; Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; Coronary Artery Disease; Electrocardiography; Exercise Test; Feasibility Studies; Female; Heart; Heart Ventricles; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Motion; Myocardial Perfusion Imaging; Nuclear Medicine; Organophosphorus Compounds; Organotechnetium Compounds; Prospective Studies; Radiopharmaceuticals; Respiration; Tellurium; Ventricular Dysfunction, Left; Zinc

Recent advances in SPECT technology including cadmium-zinc-telluride (CZT) semiconductor detector material may pave the way for absolute myocardial blood flow (MBF) measurements by SPECT. The aim of the present study was to compare K. Absolute MBF was assessed in 28 consecutive patients undergoing adenosine stress-rest myocardial perfusion imaging (MPI) by. Median MBF at rest was comparable between CZT and PET (0.89 [interquartile range (IQR), 0.77-1.00] vs. 0.92 [IQR, 0.78-1.06] mL/g/min; P = not significant) whereas it was significantly lower at stress in CZT than PET (1.11 [IQR, 1.00-1.26] vs. 2.06 [IQR, 1.48-2.56] mL/g/min; P < 0.001). This resulted in median MFRi values of 1.32 (IQR, 1.13-1.52) by CZT and 2.36 (IQR, 1.57-2.71) by PET (P < 0.001). The receiver-operator-characteristic curve revealed a cutoff for CZT MFRi at 1.26 to predict an abnormal PET MFR yielding an accuracy of 75%.. The estimation of absolute MBF index values by CZT SPECT MPI with

Topics: Adenosine; Aged; Ammonia; Cadmium; Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; Female; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Nitrogen Radioisotopes; Organophosphorus Compounds; Organotechnetium Compounds; Positron-Emission Tomography; Rest; ROC Curve; Stress, Physiological; Tellurium; Zinc

Proton-pump inhibitors (PPIs) induce potentially interfering stomach wall activity in single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) with technetium-99m ((99m)Tc)-sestamibi. However, no data are available for (99m)Tc-tetrofosmin. We assessed the influence of prolonged (>2 weeks) PPI use on the stomach wall uptake of (99m)Tc-tetrofosmin in patients referred for stress MPI with a cadmium-zinc-telluride-based SPECT camera and its relation with dyspepsia symptoms.. Consecutive patients (n=127) underwent a 1-day adenosine stress-first SPECT-MPI with (99m)Tc-tetrofosmin, of whom 54 (43%) patients had been on PPIs for more than 2 weeks. Stomach wall activity was identified on stress SPECT using computed tomographic attenuation maps and was scored using a four-point grading scale into clinically relevant (scores 2 or 3) or nonrelevant (scores 0 or 1).Patients on PPIs had stomach wall uptake more frequently as compared with patients not using PPIs (22 vs. 7%, P=0.017). Dyspepsia was similar in both groups.. Prolonged use of PPIs is associated with stomach wall uptake of (99m)Tc-tetrofosmin in stress cadmium-zinc-telluride-SPECT images. Gastric symptoms were not associated with stomach wall uptake.

Topics: Aged; Artifacts; Biological Transport; Cadmium; Dyspepsia; Female; Gastric Mucosa; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Proton Pump Inhibitors; Stomach; Stress, Physiological; Tellurium; Time Factors; Tomography, Emission-Computed, Single-Photon; Tomography, X-Ray Computed; Zinc

Data on the in vivo myocardial kinetics of (123)I-metaiodobenzylguanidine ((123)I-MIBG) are scarce and have always been obtained using planar acquisitions. To clarify the normal kinetics of (123)I-MIBG in vivo over time, we designed an experimental protocol using a 3-dimensional (3D) dynamic approach with a cadmium zinc telluride (CZT) camera.. We studied 6 anesthetized pigs (mean body weight, 37 ± 4 kg). Left ventricular myocardial perfusion and sympathetic innervation were assessed using (99m)Tc-tetrofosmin (26 ± 6 MBq), (123)I-MIBG (54 ± 14 MBq), and a CZT camera. A normal perfusion/function match on gated SPECT was the inclusion criterion. A dynamic acquisition in list mode started simultaneously with the bolus injection of (123)I-MIBG, and data were collected every 5 min for the first 20 min and then at acquisition steps of 30, 60, 90, and 120 min. Each step was reconstructed using dedicate software and reframed (60 s/frame). On the reconstructed transaxial slice that best showed the left ventricular cavity, regions of interest were drawn to obtain myocardial and blood pool activities. Myocardial time-activity curves were generated by interpolating data between contiguous acquisition steps, corrected for radiotracer decay and injected dose, and fitted to a bicompartmental model. Time to myocardial maximum signal intensity (MSI), MSI value, radiotracer retention index (RI, myocardial activity/blood pool integral), and washout rate were calculated. The mediastinal signal was measured and fitted to a linear model.. The myocardial MSI of (123)I-MIBG was reached within 5.57 ± 4.23 min (range, 2-12 min). The mean MSI was 0.426% ± 0.092%. Myocardial RI decreased over time and reached point zero at 176 ± 31 min (range, 140-229 min). The ratio between myocardial and mediastinal signal at 15 and 125 min and extrapolated at 176 and 4 h was 5.45% ± 0.61%, 4.33% ± 1.23% (not statistically significant vs. 15 min), 3.95% ± 1.46% (P < 0.03 vs. 125 min), and 3.63% ± 1.64% (P < 0.03 vs. 176 min), respectively. Mean global washout rate at 125 min was 15% ± 14% (range, 0%-34%), and extrapolated data at 176 min and 4 h were 18% ± 18% (range, 0.49%-45%) and 25% ± 23% (range, 1.7%-56.2%; not statistically significant vs. 176 min), respectively.. 3D dynamic analysis of (123)I-MIBG suggests that myocardial peak uptake is reached more quickly than previously described. Myocardial RI decreases over time and, on average, is null about 3 h after injection. The combination of an early peak and variations in delayed myocardial uptake could result in a wide physiologic range of washout rates. Mediastinal activity appears to be constant over time and significantly lower than previously described in planar studies, resulting in a higher heart-to-mediastinum ratio.

Topics: 3-Iodobenzylguanidine; Animals; Cadmium; Disease Models, Animal; Heart; Heart Ventricles; Imaging, Three-Dimensional; Iodine Radioisotopes; Models, Statistical; Myocardium; Organophosphorus Compounds; Organotechnetium Compounds; Oxygen Consumption; Perfusion; Radiopharmaceuticals; Swine; Sympathetic Nervous System; Tellurium; Time Factors; Tomography, Emission-Computed, Single-Photon; Zinc

Recently introduced ultrafast cardiac SPECT cameras with cadmium zinc telluride-based (CZT) detectors may provide superior image quality allowing faster acquisition with reduced radiation doses. Although the level of concordance between conventional SPECT and invasive fractional flow reserve (FFR) measurement has been studied, that between FFR and CZT-based SPECT is not yet known. Therefore, we aimed to assess the level of concordance between CZT SPECT and FFR in a large patient group with stable coronary artery disease.. Both invasive FFR and myocardial perfusion imaging with a CZT-based SPECT camera, using Tc-tetrofosmin as tracer, were performed in 100 patients with stable angina and intermediate grade stenosis on invasive coronary angiography. A cut-off value of <0.75 was used to define abnormal FFR.. The mean age of the patients was 64 ± 11 years, and 64 % were men. SPECT demonstrated ischaemia in 31 % of the patients, and 20 % had FFR <0.75. The concordance between CZT SPECT and FFR was 73 % on a per-patient basis and 79 % on a per-vessel basis. Discordant findings were more often seen in older patients and were mainly (19 %) the result of ischaemic SPECT findings in patients with FFR ≥ 0.75, whereas only 8 % had an abnormal FFR without ischaemia as demonstrated by CZT SPECT.. Only 20 - 30 % of patients with intermediate coronary stenoses had significant ischaemia as assessed by CZT SPECT or invasive FFR. CZT SPECT showed a modest degree of concordance with FFR, which is comparable with previous results with conventional SPECT. Further investigations are particularly necessary in patients with normal SPECT and abnormal FFR, especially to determine whether these patients should undergo revascularization.

Topics: Aged; Cadmium; Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; Coronary Artery Disease; Female; Fractional Flow Reserve, Myocardial; Gamma Cameras; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Tellurium; Zinc

To evaluate the relationships among myocardial sympathetic innervation, perfusion and mechanical synchronicity assessed with cardiac cadmium-zinc-telluride (CZT) scintigraphy.. A group of 29 patients underwent an evaluation of myocardial perfusion with (99m)Tc-tetrofosmin CZT scintigraphy and adrenergic innervation with (123)I-metaiodobenzylguanidine (MIBG) CZT scintigraphy. The summed rest score (SRS), motion score (SMS) and thickening score (STS), as well as the summed (123)I-MIBG defect score (SS-MIBG), were determined. Regional tracer uptake for both (99m)Tc-tetrofosmin and (123)I-MIBG was also calculated. Finally, the presence of significant myocardial mechanical dyssynchrony was evaluated in phase analysis on gated CZT images and the region of latest mechanical activation identified.. Significant mechanical dyssynchrony was present in 17 patients (59 %) and associated with higher SRS (P = 0.030), SMS (P < 0.001), STS (P = 0.003) and early SS-MIBG (P = 0.037) as well as greater impairments in left ventricular ejection fraction (P < 0.001) and end-diastolic volume (P < 0.001). In multivariate analysis a higher end-diastolic volume remained the only predictor of mechanical dyssynchrony (P = 0.047). Interestingly, while in the whole population regional myocardial perfusion and adrenergic activity were strongly correlated (R = 0.68), in patients with mechanical dyssynchrony the region of latest mechanical activation was predicted only by greater impairment in regional (123)I-MIBG uptake (P = 0.012) that overwhelmed the effect of depressed regional perfusion.. Left ventricular mechanical dyssynchrony is associated with greater depression in contractile function and greater impairments in regional myocardial perfusion and sympathetic activity. In patients with dyssynchrony, the region of latest mechanical activation is characterized by a significantly altered adrenergic tone.

Topics: 3-Iodobenzylguanidine; Aged; Cadmium; Cardiac-Gated Single-Photon Emission Computer-Assisted Tomography; Female; Gamma Cameras; Heart Ventricles; Humans; Male; Middle Aged; Myocardial Contraction; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Stroke Volume; Sympathetic Fibers, Postganglionic; Tellurium; Ventricular Dysfunction, Left; Zinc

To investigate the relationships between regional adrenergic innervation heterogeneity, myocardial perfusion, and contractile function obtained by means of a low-dose imaging protocol with a cadmium-zinc-telluride (CZT) dedicated camera.. Twenty-eight patients with or without ischaemic heart disease underwent (123)I-metaiodobenzylguanidine (MIBG) planar scintigraphic and CZT early and delayed evaluations followed by (99m)Tc-tetrofosmin rest gated CZT with a single-day protocol. The heart-to-mediastinum ratio and the washout rate were computed from planar (123)I-MIBG images. The summed (123)I-MIBG defect scores (SS-MIBG) were semi-quantitatively assessed from CZT images. The summed rest score (SRS), summed motion score (SMS), and summed thickening score (STS) were quantitated from (99m)Tc-tetrofosmin images.. Sixteen patients showed a depressed left ventricular systolic function [ejection fraction (EF)<50%]. They presented higher SRS (P = 0.007), SMS (P < 0.001), STS (P < 0.001), and early SS-MIBG (P = 0.007) values than those with normal contractile function. Interestingly, higher early SS-MIBG values, index of regional sympathetic innervation heterogeneity, clustered with more elevated SRS (P = 0.023), and more impaired measures of regional and global left ventricle systolic function, i.e. SMS (P = 0.046), STS (P = 0.014), and EF (P = 0.027). At multivariate analysis, a higher SRS (P = 0.039) remained the only independent predictor of more elevated early SS-MIBG values. In the 20 of 28 ischaemic patients, the correlations between early SS-MIBG and SMS (P = 0.017) and also STS (P = 0.036) were further confirmed. The effective dose of the investigation was 4.2 ± 0.72 mSv.. An altered early SS-MIBG, assessed with a low-dose imaging protocol and a CZT cardiac camera, identifies patients with more impaired myocardial perfusion and contractile function.

Topics: 3-Iodobenzylguanidine; Adrenergic Neurons; Aged; Cadmium; Female; Heart; Humans; Male; Middle Aged; Myocardial Ischemia; Organophosphorus Compounds; Organotechnetium Compounds; Radiographic Image Interpretation, Computer-Assisted; Radiopharmaceuticals; Tellurium; Tomography, Emission-Computed, Single-Photon; Zinc

To evaluate the relationships between measures of left ventricular (LV) filling dynamics at cadmium-zinc-telluride (CZT) imaging and indexes of LV diastolic function at transthoracic echocardiography.. Two hundred and forty-seven patients underwent myocardial perfusion imaging at rest and after stress with a low-dose CZT protocol and a baseline transthoracic echocardiography study. All patients were submitted to invasive or computed coronary angiography. The peak filling rate (PFR) and the time to PFR (TPFR) were derived from gated CZT images as measures of LV filling dynamics. LV diastolic function was also evaluated at echocardiography and the presence of significantly increased LV filling pressures determined. Increased LV filling pressures at transthoracic echocardiography were evident in 103 (42%) patients. Interestingly, independently from the presence of coronary artery disease, there was a strict correlation between the presence and severity of LV diastolic dysfunction at echocardiography and CZT-derived measures of filling dynamics, i.e., PFR (P = 0.001) and TPFR (P = 0.001). At receiving operating characteristic analysis, a composite index of reduced PFR (≤2.11 end-diastolic volume s(-1)) and increased TPFR (>234 ms) showed a sensitivity of 84% and a specificity of 67% in unmasking the presence of elevated LV filling pressures at echocardiography.. CZT-derived measures of LV filling dynamics correlate with echocardiographic parameters of diastolic function and may identify the presence of increased LV filling pressures.

Topics: Aged; Cadmium; Coronary Angiography; Coronary Artery Disease; Echocardiography, Doppler; Exercise Test; Female; Humans; Image Interpretation, Computer-Assisted; Male; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Tellurium; Ventricular Dysfunction, Left; Zinc

For a 1-day myocardial perfusion SPECT (MPS) the recommendations for administered activity stated in the EANM guidelines results in an effective dose of up to 16 mSv per patient. Recently, a gamma camera system, based on cadmium zinc telluride (CZT) technology, was introduced. This technique has the potential to reduce the effective dose and scan time compared to the conventional NaI gamma camera. The aim of this study was to investigate if the effective dose can be reduced with a preserved image quality using CZT technology in MPS.. In total, 150 patients were included in the study. All underwent a 1-day (99m)Tc-tetrofosmin stress-rest protocol and were divided into three subgroups (n = 50 in each group) with 4, 3, and 2.5 MBq/kg body weight of administered activity in the stress examination, respectively. The acquisition time was increased in proportion to the decrease in administered activity. All examinations were analyzed for image quality by visual grading on a 4-point scale (1 = poor, 2 = adequate, 3 = good, 4 = excellent), by two expert readers.. The total effective dose (stress + rest) decreased from 9.3 to 5.8 mSv comparing 4 to 2.5 MBq/kg body weight. For the patients undergoing stress examination only (35%) the effective dose, administrating 2.5 MBq/kg, was 1.4 mSv. The image acquisition times for 2.5 MBq/kg body weight were 475 and 300 seconds (stress and rest) compared to 900 seconds for each when using conventional MPS. The average image quality was 3.7 ± 0.5, 3.8 ± 0.5, and 3.8 ± 0.4 for the stress images and 3.5 ± 0.6, 3.6 ± 0.6, and 3.5 ± 0.6 for the rest images and showed no statistically significant difference (P = .62) among the 4, 3, and 2.5 MBq/kg groups.. The new CZT technology can be used to considerably decrease the effective dose and acquisition time for MPS with preserved high image quality.

Topics: Aged; Body Weight; Cadmium; Coronary Artery Disease; Female; Gamma Cameras; Humans; Image Processing, Computer-Assisted; Likelihood Functions; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Perfusion; Radiation Dosage; Radiometry; Radiopharmaceuticals; Tellurium; Time Factors; Tomography, Emission-Computed, Single-Photon; Treatment Outcome; Zinc

Cadmium zinc telluride (CZT) detectors with linear counting rate response enable count subtraction in sequential scanning. We evaluated whether count subtraction eliminated the need for higher activity doses in the second part of the 1-d stress-rest myocardial perfusion imaging (MPI) protocol.. For 50 patients (mean age ± SD, 66 ± 12 y) with visually abnormal (n = 42) or equivocal (n = 8) adenosine-stress MPI (320 MBq of (99m)Tc-tetrofosmin) on a CZT camera, rest MPI was performed with a low dose (320 MBq) and repeated after injection of an additional 640 MBq of (99m)Tc-tetrofosmin to achieve a standard 3-fold increased dose at rest (960 MBq), compared with stress (320 MBq). Low-dose rest myocardial perfusion images were reconstructed after subtracting the background activity of the preceding stress scan. Segmental percentage tracer uptake of the 2 rest myocardial perfusion images (320 vs. 960 MBq) was compared using intraclass correlation and Bland-Altman limits of agreement. Patient- and coronary territory-based clinical agreement was assessed.. The standard protocol revealed ischemia in 34 (68%) and a fixed defect in 8 (16%) patients, of whom 33 (97%) and 8 (100%) were correctly identified by low-dose MPI (clinical agreement, 98%). Segmental uptake correlated well between low- and standard-dose rest scans (r = 0.94, P < 0.001; Bland-Altman limits of agreement, -11 to +11%). Defect extent was 14.4% (low-dose) versus 13.1% (standard-dose) at rest (P = not statistically significant) and 26.6% at stress (P < 0.001 vs. rest scans).. These promising results suggest that accurate assessment of ischemic myocardial disease is feasible with a low-dose-low-dose 1-d SPECT MPI protocol using a CZT device.

Topics: Adult; Aged; Aged, 80 and over; Cadmium; Female; Humans; Image Processing, Computer-Assisted; Ischemia; Male; Middle Aged; Myocardial Perfusion Imaging; Organophosphorus Compounds; Organotechnetium Compounds; Phantoms, Imaging; Radiopharmaceuticals; Semiconductors; Tellurium; Tomography, Emission-Computed, Single-Photon; Zinc

We aimed at establishing the optimal scan time for nuclear myocardial perfusion imaging (MPI) on an ultrafast cardiac gamma-camera using a novel cadmium-zinc-telluride (CZT) solid-state detector technology.. Twenty patients (17 male; BMI range, 21.7-35.5 kg/m(2)) underwent 1-d (99m)Tc-tetrofosmin adenosine stress and rest MPI protocols, each with a 15-min acquisition on a standard dual-detector SPECT camera. All scans were immediately repeated on an ultrafast CZT camera over a 6-min acquisition time and reconstructed from list-mode raw data to obtain scan durations of 1 min, 2 min, etc., up to a maximum of 6 min. For each of the scan durations, the segmental tracer uptake value (percentage of maximum myocardial uptake) from the CZT camera was compared by intraclass correlation with standard SPECT camera data using a 20-segment model, and clinical agreement was assessed per coronary territory. Scan durations above which no further relevant improvement in uptake correlation was found were defined as minimal required scan times, for which Bland-Altman limits of agreement were calculated.. Minimal required scan times were 3 min for low dose (r = 0.81; P < 0.001; Bland-Altman, -11.4% to 12.2%) and 2 min for high dose (r = 0.80; P < 0.001; Bland-Altman, -7.6% to 12.9%), yielding a clinical agreement of 95% and 97%, respectively.. We have established the minimal scan time for a CZT solid-state detector system, which allows 1-d stress/rest MPI with a substantially reduced acquisition time resulting in excellent agreement with regard to uptake and clinical findings, compared with MPI from a standard dual-head SPECT gamma-camera.

Topics: Adult; Aged; Aged, 80 and over; Cadmium; Coronary Artery Disease; Coronary Circulation; Dose-Response Relationship, Drug; Female; Gamma Cameras; Heart; Humans; Image Processing, Computer-Assisted; Linear Models; Male; Microcomputers; Middle Aged; Organophosphorus Compounds; Organotechnetium Compounds; Perfusion; Phantoms, Imaging; Radiopharmaceuticals; Tellurium; Tomography, Emission-Computed, Single-Photon; Zinc

To assess the diagnostic performance of a novel ultrafast cardiac gamma camera with cadmium-zinc-telluride (CZT) solid-state semiconductor detectors for nuclear myocardial perfusion imaging (MPI).. The study group comprised 75 consecutive patients (55 men, BMI range 19-45 kg/m(2)) who underwent a 1-day (99m)Tc-tetrofosmin adenosine-stress/rest imaging protocol. Scanning was performed first on a conventional dual-detector SPECT gamma camera (Ventri, GE Healthcare) with a 15-min acquisition time each for stress and rest. All scans were immediately repeated on an ultrafast CZT camera (Discovery 530 NMc, GE Healthcare) with a 3-min scan time for stress and a 2-min scan time for rest. Clinical agreement (normal, ischaemia, scar) between CZT and SPECT was assessed for each patient and for each coronary territory using SPECT MPI as the reference standard. Segmental myocardial tracer uptake values (percent of maximum) using a 20-segment model and left ventricular ejection fraction (EF) values obtained using CZT were compared with those obtained using conventional SPECT by intraclass correlation and by calculating Bland-Altman limits of agreement.. There was excellent clinical agreement between CZT and conventional SPECT on a per-patient basis (96.0%) and on a per-vessel territory basis (96.4%) as shown by a highly significant correlation between segmental tracer uptake values (r=0.901, p<0.001). Similarly, EF values for both scanners were highly correlated (r=0.976, p<0.001) with narrow Bland-Altman limits of agreement (-5.5-10.6%).. The novel CZT camera allows a more than fivefold reduction in scan time and provides clinical information equivalent to conventional standard SPECT MPI.

Topics: Adenosine; Adult; Aged; Aged, 80 and over; Cadmium; Equipment Design; Exercise Test; Female; Gamma Cameras; Heart; Humans; Male; Middle Aged; Myocardial Perfusion Imaging; Observer Variation; Organophosphorus Compounds; Organotechnetium Compounds; Radiopharmaceuticals; Semiconductors; Single-Blind Method; Tellurium; Time Factors; Tomography, Emission-Computed, Single-Photon; Zinc