Cardiac Cadmium-zinc-telluride Research Articles

Impact of CT attenuation correction on viable myocardium detection in combined SPECT and PET/CT: A retrospective cohort study.

The influence of computed tomography attenuation correction (CTAC) on the accuracy of diagnosing viable myocardium using Tc-99m-MIBI dedicated cardiac cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) combined with F-18-FDG Positron Emission Tomography/Computed Tomography (PET/CT) metabolic imaging, compared with conventional SPECT MPI, remains to be fully elucidated. To evaluate the impact of CTAC on the accuracy of diagnosing viable myocardium using Tc-99m-MIBI dedicated cardiac CZT SPECT MPI combined with F-18-FDG PET/CT, compared to conventional SPECT MPI. 193 patients underwent CZT SPECT and F-18-FDG PET/CT imaging, while 39 patients underwent conventional SPECT and F-18-FDG PET/CT imaging, with both groups utilizing CT for attenuation correction. The injured myocardium (hibernating and scarring) was quantified using the Q.PET software. After CTAC, both groups showed significant improvements in perfusion of the injured myocardial areas, particularly in the inferior wall (INF). The reduction in perfusion was more notable in the CZT SPECT group than that in the conventional group, particularly in the inferior and lateral walls. Among patients with large cardiac chambers, those undergoing MPI with CZT, with normal weights, or males, hibernating myocardium (HM) and scar post-CTAC reductions were particularly significant in the INF. If HM ≥ 10% is considered an indicator for recommended revascularization, among the 87 patients without prior cardiac bypass, 25 (28.7%) might not require revascularization treatment. Dedicated cardiac CZT SPECT and conventional SPECT MPI combined with F-18-FDG PET/CT significantly influenced the assessment of viable myocardium. The impact of CTAC was more profound in dedicated cardiac CZT SPECT, particularly in the INF region. CTAC significantly enhances the accuracy of viable myocardial assessment and may influence clinical decisions regarding revascularization therapy. Therefore, CTAC should be routinely used in dedicated cardiac CZT SPECT MPI combined with F-18-FDG PET/CT for myocardial viability diagnosis.

An Algorithm for Individual Dosage in Cadmium-Zinc-Telluride SPECT-Gated Radionuclide Angiography.

The aim of the present study was to test an individualised dose without compromising the ease of analysing data when performing equilibrium radionuclide angiography (ERNA) using cadmium–zinc–telluride (CZT) SPECT. From March 2018 to January 2019, 1650 patients referred for ERNA received either an individualised dose of 99mTc-labeled human serum albumin (HSA) according to their age, sex, height, and weight (n = 1567), or a standard dose of 550 MBq (n = 83). The target count rate (CRT) was reduced every two months from 2.7 to 1.0 kcps. A final test with a CRT of 1.7 kcps was run for three months to test whether an agreement within 2% points for the determination of LVEF, on the basis of only two analyses, was obtainable in at least 95% of acquisitions. All the included ERNAs were performed on a dedicated cardiac CZT SPECT camera. When using the algorithm for an individualised dose, we found that agreement between the measured and predicted count rate was 80%. With a CRT of 1.7 kcps, the need for more than two analyses to obtain sufficient agreement for LVEF was 4.9%. Furthermore, this resulted in a mean dose reduction from 550 to 258 MBq. Patients’ weight, height, sex, and age can, therefore, be used for individualising a tracer dose while reducing the mean dose.

Prognostic Value of Diastolic Dysfunction Derived From D-SPECT in Coronary Artery Disease Patients With Normal Ejection Fraction.

Diastolic dysfunction (DD) with normal systolic function has been elucidated to be associated with heart failure and worse prognosis. The recently introduced single photon emission computed tomography (SPECT) with dedicated cardiac cadmium-zinc-telluride (CZT) cameras (D-SPECT) is a novel method to quantitate left ventricular functional parameters. We aimed to evaluate the prognostic value of DD derived from D-SPECT in coronary artery disease (CAD) patients with normal ejection fraction. All CAD patients who underwent D-SPECT and invasive coronary angiography within 3 months were considered. DD was defined as peak filling rate (PFR) <2.1 end diastolic volume (EDV, ml)/s according to the D-SPECT results. Patients were divided into three groups: group 1 (n = 226)—normal PFR; group 2 (n = 67)—ischemia-related DD (abnormal stress PFR and normal rest PFR); and group 3 (n = 106)—rest DD (abnormal rest PFR). The primary clinical endpoint of the present study was a composite of heart failure events (HFE). A total of 399 consecutive CAD patients with normal systolic function undergoing stress D-SPECT were analyzed. The incidence rates of HFE among the three groups were 4.0, 7.5, and 11.3%, respectively. Cox regression analysis showed that the multivariate predictors of HFE were rest PFR, diabetes mellitus, obesity, and old age. DD derived from D-SPECT in CAD patients with normal ejection fraction is predictive of HFE.

First comparison of performances between the new whole-body cadmium–zinc–telluride SPECT-CT camera and a dedicated cardiac CZT camera for myocardial perfusion imaging: Analysis of phantom and patients

BackgroundDedicated cardiac Cadmium–zinc–telluride (CZT) cameras show superior performances compared with Anger systems, particularly in terms of spatial resolution and count sensitivity. This study evaluated the performances of a new polyvalent whole body CZT camera (DNM 670CZT) compared with a cardiac dedicated CZT camera (DNM 530c) for myocardial perfusion SPECT. MethodsThe spatial resolution was evaluated with three linear sources filled with 99mTc. We used a cardiac phantom to evaluate count sensitivity, sharpness index, contrast-to-noise ratio, wall thickness, non-uniformity index, perfusion scores and ventricle volumes for both cameras. The impact of matrix size, and acquisition time was investigated. Concordance between the two cameras was evaluated in patients using QPS/QGS software for quantitative segmental perfusion, motion and thickness scores. ResultsThe spatial resolution was identical with the two cameras. Count sensitivity of the DNM 670CZT was twofold lower compared with the DNM 530c, leading to lower sharpness index and contrast-to-noise ratio. The wall thickness and the myocardial volumes were similar. Visual and quantitative assessments of the perfusion patterns have shown a good concordance of the two cameras on phantoms and in patients. ConclusionThis study demonstrated the feasibility of myocardial perfusion SPECT imaging using the new whole-body DNM 670CZT camera.

Technological advances and clinical application progress of the dedicated cardiac cadmium-zinc-telluride SPECT

The dedicated cardiac cadmium-zinc-telluride (CZT) SPECT device has been commercially applied to the clinics in recent years. Compared to the traditional SPECT, cardiac CZT SPECT has better image quality, higher spatial and energy resolution with shorter acquisition duration and lower radiation exposure. With these advantages, the clinical application of cardiac CZT SPECT is of great potential. This review summarizes the technological advances, clinical progress and current shortages of cardiac CZT SPECT. Key words: Tomography, emission-computed, single-photon; Heart; Tellurium; Zinc; Cadmium; Trends

Relationships between left ventricular sympathetic innervation and diastolic dysfunction: the role of myocardial innervation/perfusion mismatch

BackgroundA possible relationship between cardiac sympathetic denervation and left ventricular (LV) diastolic dysfunction has been suggested. However, an evaluation of the interactions between myocardial adrenergic tone and LV perfusion and diastolic function is lacking. Methods and resultsSeventy-two patients underwent 99mTc-tetrofosmin/123I-metaiodobenzylguanidine (123I-MIBG) cardiac Cadmium-Zinc-Telluride (CZT) imaging. The summed rest score (SRS) and summed 123I-MIBG score (SS-MIBG) were computed as measures of regional perfusion and innervation heterogeneities. LV segments showing an impaired innervation, despite a relatively preserved perfusion (99mTc-tetrofosmin-123I-MIBG tracers’ uptake ≥25%), were individuated (innervation/perfusion mismatch). The peak filling rate (PFR) was computed as a measure of LV diastolic function. Nineteen of the 72 (26%) patients presented a normal LV diastolic function, while 29 (40%) and 24 (34%) had a mild and overt diastolic dysfunction. Subjects with diastolic dysfunction showed more abnormal SRS and SS-MIBG values (P < 0.001). In the global population, 502/1224 (41%) LV segments showed an innervation/perfusion mismatch. A modest correlation between the extent of cardiac innervation/perfusion mismatch and PFR values was evident (R = −0.27, P = 0.029). On multivariate analysis, the extent of regional innervation/perfusion mismatch remained an independent predictor of overt LV diastolic abnormalities (P = 0.017). ConclusionsThe burden of LV regions showing an innervation/perfusion mismatch associates with the occurrence of overt diastolic dysfunction.

Imaging of the thyroid and parathyroid using a cardiac cadmium zinc telluride camera: Phantom studies.

Purpose: Cadmium zinc telluride (CZT) detectors have recently been introduced to the field of clinical nuclear cardiology. However, the feasibility of using them for organs other than the heart remains unclear. The aim of this study was to evaluate the potential of a cardiac CZT camera to acquire thyroid and parathyroid images. We used custom-made phantoms and the currently available standard protocols for CZT, instead of a sodium-iodine scintillation (NaI) camera. Materials and Methods: Thyroid phantoms with or without parathyroid adenomas were made from agar using radiopharmaceuticals (99mTc or 123I) and imaged using CZT and NaI cameras. Using the CZT camera data, we prepared maximum intensity projection (MIP) images and planar equivalent (PE) images. Image counts were compared to those from the NaI camera, and the radioactivity of the phantoms was measured. For parathyroid imaging, three different protocols with the NaI camera were tested using MIP images. Results: For thyroid imaging, MIP could provide images as clear as those obtained from the NaI camera. The radioactivity and image counts correlated better for the PE images than the MIP images, especially for 123I images. We succeeded in obtaining clear parathyroid adenoma images from MIP images using all three protocols. Conclusion: A cardiac CZT camera can effectively perform qualitative and quantitative assessments of the thyroid and parathyroid organs.

Quantification of myocardial perfusion reserve using dynamic SPECT images of patients with chronic kidney disease

BackgroundChronic kidney disease (CKD) is an independent risk factor for cardiovascular disorders. The aim of this study was to examine whether the quantitatively measured myocardial blood flow (MBF) or myocardial perfusion reserve (MPR), calculated by dynamic single photon emission computed tomography (SPECT) analysis using a cardiac cadmium zinc telluride (CZT) gamma camera, was related to renal dysfunction in patients with normal myocardial perfusion imaging (MPI) findings. MethodsThe study population consisted of 46 patients with CKD and 46 individuals without CKD (controls). Their MPR index was quantitatively measured using adenosine MPI with a cardiac CZT gamma camera. All assessments were with a single tissue compartment kinetic model. The K1 value was calculated on stress and at-rest images. To obtain the MPR index we divided K1 stress-by K1 at-rest values. ResultsThe at-rest K1 value was significantly higher and the MPR index was significantly lower in patients with CKD than those without CKD [CKD vs. controls: at-rest K1 value, 0.21 (0.17–0.25) vs. 0.19 (0.16–0.22), p=0.040; MPR index, 1.86 (1.69–2.22) vs. 2.19 (1.93–2.41), p<0.001]. The stress K1 values were not significantly different. ConclusionThe MPR index is significantly lower in CKD patients; this is considered as being mainly due to an increase in the at-rest K1 value.

The effect of CT-based attenuation correction on the automatic perfusion score of myocardial perfusion imaging using a dedicated cardiac solid-state CZT SPECT/CT

BackgroundData regarding cardiac cadmium-zinc-telluride (CZT)-specific augmented databases and their impact on CT-based attenuation correction (AC) perfusion scores in myocardial perfusion imaging (MPI) were obtained on a multiple-pinhole CZT SPECT/CT. Methods and ResultsSummed stress (SSS) and rest scores (SRS) were measured using automated software in three independent patient groups: group 1 (n = 80) underwent MPI on both CZT and conventional sodium iodide (NaI) devices, group 2 (n = 80) with low coronary artery disease likelihood and normal MPI provided reference CZT databases; and group 3 (n = 152) served to compare AC and non-AC (NAC) scores on CZT. Group 1 CZT and NaI scores gave a significant 1:1 linear correlation for CZT scores referenced to the custom database vs NaI scores referenced to the default database, but these were not concordant when CZT scores were referenced to the default database. AC significantly decreased average SSS and SRS in men vs NAC, 4.29 ± 6.30 vs 5.37 ± 7.26 (P < 0.001) and 2.37 ± 4.72 vs 3.13 ± 5.85 (P < 0.001), but not in women, 2.28 ± 3.42 vs 2.28 ± 3.08 (p NS) and 0.46 ± 1.51 vs 0.61 ± 1.86, (p NS), respectively. ConclusionsSpecifically designed databases for solid-state CZT cardiac SPECT provide accurate quantitation of perfusion scores concordant with those previously validated for conventional SPECT. AC and NAC CZT scores differed significantly, especially in men.

Accuracy of myocardial perfusion imaging in detecting multivessel coronary artery disease: A cardiac CZT study

BackgroundMyocardial perfusion imaging (MPI) performed on traditional single-photon emission computed-tomography cameras has been shown to have a sub-optimal accuracy in detecting multivessel coronary artery disease (CAD). MethodsSix-hundred and ninety-five patients were submitted to MPI on a novel cadmium-zinc-telluride (CZT) camera and coronary angiography. A coronary stenosis >70% was considered obstructive. In every patient, the summed stress score (SSS) was computed. Moreover, the regional stress scores were also calculated for every coronary territory. ResultsFour-hundred and forty-one patients had obstructive CAD in one (28%), two (19%), or three (17%) vessels. At per-patient analysis, the SSS showed a significant accuracy in detecting obstructive CAD (AUC 0.87, P < .001). Specifically, its accuracy was maintained also in patients with double (AUC 0.83; P < .001) or triple-vessels disease (AUC 0.79, P < .001), where CZT was able to correctly identify CAD extent in 64% of patients. On a per-vessel basis, CZT confirmed its high accuracy in detecting obstructive CAD (AUC 0.88, P < .001), independently from the involved coronary vessel. ConclusionsMPI performed on a CZT camera is highly accurate in detecting obstructive CAD, independently from the coronary artery involved and the overall disease burden.

Association between left ventricular regional sympathetic denervation and mechanical dyssynchrony in phase analysis: a cardiac CZT study

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.

Comparison of Myocardial Perfusion Imaging Using Thallium-201 Between a New Cadmium-Zinc-Telluride Cardiac Camera and a Conventional SPECT Camera

Cadmium zinc telluride (CZT) solid-state detectors have been recently introduced in myocardial perfusion imaging. However, they had not been yet validated with thallium-201. This study compares the clinical performances of the CZT ultrafast camera GE DNM 530c with a conventional SPECT camera (CC) using thallium-201. We prospectively studied with thallium-201 a total of 153 consecutive patients referred for myocardial perfusion imaging at exercise (3-4 mCi) then redistribution (with 1 mCi reinjection). Sequential acquisitions were performed first with a conventional dual-head tomographic Anger camera (CC) in 10 to 15 minutes and then with a CZT camera (CZT) in 5 minutes, in prone position. In all, 9 patients were excluded: 1 for mispositioning, 3 for camera failure, 3 for delayed acquisition after exercise, 1 for nonacceptance of redistribution, 1 for motion. Acquisition was more comfortable with CZT for all patients. Global counts rate was higher with CZT than with CC (3.6±0.57 KCts/s vs. 1.14±0.16). CZT has a 5-fold increased myocardial counts rate compared with CC (448±69 Kcts in 5 minutes vs. 209±40 Kcts in 12.5±1.8 minutes). Quality of CZT images was considered as better in 40%, equal in 56%, and worse in 4% of cases; we found less artifacts with CZT; diagnostic conclusions were the same in 140 of 144 cases (97%); discordances were 2 artifacts with CC and 2 small ischemia (less than 2 segments) missed by CZT. This new dedicated cardiac CZT camera allows with thallium-201 five minutes acquisitions with an increased image quality and a reliable diagnosis quality.