ABSTRACT
OBJECTIVE: A recently introduced single-photon emission computed tomography (SPECT), based on cadmium-zinc-telluride (CZT) detectors (D-SPECT), supports high energy resolution for cardiac imaging. Importantly, the high energy resolution may allow simultaneous dual-isotope (SDI) imaging (e.g., using Tc-99m and I-123). We quantitatively evaluated Tc-99m/I-123 SDI imaging by D-SPECT in comparison with conventional T1-201/I-123.MATERIALS AND METHODS: Energy resolution was measured as a percentage of the full width at half maximum(FWHM) for Tc-99m, I-123, and Tl-201. The impact of cross-talk and reconstructed image contrast were quantified by measuring the contrast-to-noise ratio (CNR), and the transmural defect contrast in the left ventricle wall (CTD) induced by a difference in energy, for combinations of Tc-99m/I-123 or Tl-201/I-123, using an RH-2 cardiac phantom. Corresponding measurement was also carried out in Anger SPECT (A-SPECT).RESULTS: The energy resolution of the D-SPECTsystem was 5.4%/5.1%for Tc-99m/I-123 and 5.4%/5.3%for Tl-201/I-123, which was approximately two times higher than the A-SPECT. No notable difference was confirmed in the CNRs of the two systems, but T1-201/I-123 showed overall higher value than Tc-99m/I-123. Compared to A-SPECT, CTD of D-SPECT significantly increased with both Tc-99m/I-123 and T1-201/I-123 (p < 0.05). In DSPECT, the combination of Tc-99m/I-123 had a slightly better CTD than T1-201/I-123. In addition, CTD of Tc-99m/I-123 was improved with scatter correction at both nuclides (p < 0.05), but in Tl-201/I-123, no significant improvement was confirmed in I-123 (p > 0.05).CONCLUSION: D-SPECT was considered to be capable of performing high-quality SDI imaging using Tc-99m/I-123.
Subject(s)
Anger , Heart Ventricles , Tomography, Emission-Computed , Tomography, Emission-Computed, Single-PhotonABSTRACT
OBJECTIVE@#A recently introduced single-photon emission computed tomography (SPECT), based on cadmium-zinc-telluride (CZT) detectors (D-SPECT), supports high energy resolution for cardiac imaging. Importantly, the high energy resolution may allow simultaneous dual-isotope (SDI) imaging (e.g., using Tc-99m and I-123). We quantitatively evaluated Tc-99m/I-123 SDI imaging by D-SPECT in comparison with conventional T1-201/I-123.@*MATERIALS AND METHODS@#Energy resolution was measured as a percentage of the full width at half maximum(FWHM) for Tc-99m, I-123, and Tl-201. The impact of cross-talk and reconstructed image contrast were quantified by measuring the contrast-to-noise ratio (CNR), and the transmural defect contrast in the left ventricle wall (CTD) induced by a difference in energy, for combinations of Tc-99m/I-123 or Tl-201/I-123, using an RH-2 cardiac phantom. Corresponding measurement was also carried out in Anger SPECT (A-SPECT).@*RESULTS@#The energy resolution of the D-SPECTsystem was 5.4%/5.1%for Tc-99m/I-123 and 5.4%/5.3%for Tl-201/I-123, which was approximately two times higher than the A-SPECT. No notable difference was confirmed in the CNRs of the two systems, but T1-201/I-123 showed overall higher value than Tc-99m/I-123. Compared to A-SPECT, CTD of D-SPECT significantly increased with both Tc-99m/I-123 and T1-201/I-123 (p 0.05).@*CONCLUSION@#D-SPECT was considered to be capable of performing high-quality SDI imaging using Tc-99m/I-123.
ABSTRACT
PURPOSE: The differences in performance between the cadmium-zinc-telluride (CZT) camera or collimation systems and conventional Anger single-photon emission computed tomography (A-SPECT) remain insufficient from the viewpoint of the user. We evaluated the performance of the D-SPECT (Spectrum Dynamics, Israel) system to provide more information to the cardiologist or radiological technologist about its use in the clinical field.MATERIALS AND METHODS: This study evaluated the performance of the D-SPECTsystem in terms of energy resolution, detector sensitivity, spatial resolution, modulation transfer function (MTF), and collimator resolution in comparison with that of A-SPECT (Bright-View, Philips, Japan). Energy resolution and detector sensitivity were measured for Tc-99m, I-123, and Tl-201. The SPECT images produced by both systems were evaluated visually using the anthropomorphic torso phantom.RESULTS: The energy resolution of D-SPECT with Tc-99m and I-123 was approximately two times higher than that of ASPECT. The detector sensitivity of D-SPECT was higher than that of A-SPECT (Tc-99m: 4.2 times, I-123: 2.2 times, and Tl-201: 5.9 times). The mean spatial resolution of D-SPECTwas two times higher than that of A-SPECT. The MTF of D-SPECT was superior to that of the A-SPECT system for all frequencies. The collimator resolution of D-SPECT was lower than that of A-SPECT; however, the D-SPECT images clearly indicated better spatial resolution than the A-SPECT images.CONCLUSION: The energy resolution, detector sensitivity, spatial resolution, and MTF of D-SPECT were superior to those of A-SPECT. Although the collimator resolution was lower than that of A-SPECT, the D-SPECT images were clearly of better quality.
Subject(s)
Anger , Cardiology , Tomography, Emission-Computed , Tomography, Emission-Computed, Single-Photon , TorsoABSTRACT
PURPOSE: This study quantified the contraction synchronicity (CS; with 100% representing full synchrony and −100% dyssynchrony) and contraction work (CW, millijoules per centimeter squared; representingmyocardial area) in patients with reduced left ventricular ejection fraction (LVEF) associated with coronary artery disease (CAD).METHODS: CS, CW and LVEF in 104 subjects (54 CAD patients and 50 control subjects without CAD) were measured using rest electrocardiography-gated single-photon emission computed tomography (ECG SPECT). Contraction amplitude (CA), synchronous contraction index (SCI), and CW were evaluated using the program Quantification of Segmental Function by Solving the Poisson Equation (QSFP) developed in-house.RESULTS: The mean CA, SCI and CW of 17 segments in the control subjects were 33.8 ± 4.1% (±SD), 96.6 ± 1.4%, and 6.9 ± 1.0 mJ/cm², respectively. In the patients with CAD, the respective values were 26.1 ± 7.3%, 82.1 ± 16.8%, and 5.4 ± 1.6 mJ/cm². In the CAD patients with LVEF <40% (n = 14), the mean CA, SCI,and CW were 17.9 ± 4.0%, 63.0 ± 18.4%, and 3.5 ± 1.1 mJ/cm², respectively. These values were significantly lower than in the control subjects (p < 0.005). Using receiver operating characteristic analysis, values for the area under the curve showing the performance of CA, CS,CWand LVEF in the diagnosis of CAD were 0.81, 0.86, 0.78, and 0.84, respectively.CONCLUSION: Asynchrony shown using the QSFP is useful for CAD detection.