Camera SPECT/CT CZT et applications de la quantification absolue en imagerie cardio-vasculaire

This work evaluated the performances of a new polyvalent whole body SPECT/CT CZT camera (DNM 670 CZT GE Healthcare ) compared with a cardiac dedicated CZT camera (DNM 530c GE Healthcare) and with an anger camera (INTEVO BOLD, Siemens Healthcare). We made phantom experiments and clinical studies, with particular interest in quantification.Despite excellent performance, the whole body SPECT/CT CZT camera has a low sensitivity compared to the dedicated CZT camera. This is likely due to the differences in detection geome-try (parallel versus multipinhole collimators).Quantification with whole body SPECT/CT CZT camera is feasible and reliable. We demonstrated the feasibility of 99mTc- HMDP quantitative measurement in patients with suspected cardiac ATTR.We investigated the feasibility and performance of this new CZT camera to quantify osteogenic activity in vascular or valvular calcification with a phantom study. It confirmed the limits of SPECT imaging to measure precisely small target, particularly related to poor sensitivity, noise to background ratio and resolution, responsible of partial volume effect.L’objectif de ce travail de thèse était d’étudier les performances de la gamma camera à semi-conducteur « grand champ » (DNM 670 CZT, GE Healthcare) de dernière génération, en réalisant des études fantômes et cliniques, et en la comparant à la caméra CZT dédié à la cardiologie (DNM 530c, GE Healthcare) et à une gamma caméra conventionnelle (INTEVO BOLD, Siemens Healthcare). Nous nous sommes particulièrement intéressés à la quantification absolue, et avons testé les limites de cette gamma caméra par différentes études fantômes.Malgré d’excellentes performances techniques, la caméra CZT « grand champ » souffre d’une moins bonne sensibilité comparativement à la caméra CZT dédié, qui est optimisée pour l’acquisition myocardique grâce à la configuration cardiofocale de ses détecteurs.La quantification absolue de l’activité radioactive grâce aux camera CZT est performante, et réali-sable en routine. Une première application clinique dans le diagnostic de l’amylose cardiaque ATTR montre des résultats extrêmement prometteurs. La mesure de la charge amyloïde par la fixation des biphosphonate-99mTc sur le myocarde semble fiable et pertinente. Nos études fan-tômes portant sur la mesure théorique de l’activité ostéoblastique de calcification vasculaire, con-firme quant à elle les limites de ces gammas caméras en quantification, en lien notamment avec leur faible résolution, sensibilité, et rapport signal sur bruit ne permettant pas une mesure fiable de l’activité de cibles de petites tailles

Camera SPECT/CT CZT et applications de la quantification absolue en imagerie cardio-vasculaire

This work evaluated the performances of a new polyvalent whole body SPECT/CT CZT camera (DNM 670 CZT GE Healthcare ) compared with a cardiac dedicated CZT camera (DNM 530c GE Healthcare) and with an anger camera (INTEVO BOLD, Siemens Healthcare). We made phantom experiments and clinical studies, with particular interest in quantification.Despite excellent performance, the whole body SPECT/CT CZT camera has a low sensitivity compared to the dedicated CZT camera. This is likely due to the differences in detection geome-try (parallel versus multipinhole collimators).Quantification with whole body SPECT/CT CZT camera is feasible and reliable. We demonstrated the feasibility of 99mTc- HMDP quantitative measurement in patients with suspected cardiac ATTR.We investigated the feasibility and performance of this new CZT camera to quantify osteogenic activity in vascular or valvular calcification with a phantom study. It confirmed the limits of SPECT imaging to measure precisely small target, particularly related to poor sensitivity, noise to background ratio and resolution, responsible of partial volume effect.L’objectif de ce travail de thèse était d’étudier les performances de la gamma camera à semi-conducteur « grand champ » (DNM 670 CZT, GE Healthcare) de dernière génération, en réalisant des études fantômes et cliniques, et en la comparant à la caméra CZT dédié à la cardiologie (DNM 530c, GE Healthcare) et à une gamma caméra conventionnelle (INTEVO BOLD, Siemens Healthcare). Nous nous sommes particulièrement intéressés à la quantification absolue, et avons testé les limites de cette gamma caméra par différentes études fantômes.Malgré d’excellentes performances techniques, la caméra CZT « grand champ » souffre d’une moins bonne sensibilité comparativement à la caméra CZT dédié, qui est optimisée pour l’acquisition myocardique grâce à la configuration cardiofocale de ses détecteurs.La quantification absolue de l’activité radioactive grâce aux camera CZT est performante, et réali-sable en routine. Une première application clinique dans le diagnostic de l’amylose cardiaque ATTR montre des résultats extrêmement prometteurs. La mesure de la charge amyloïde par la fixation des biphosphonate-99mTc sur le myocarde semble fiable et pertinente. Nos études fan-tômes portant sur la mesure théorique de l’activité ostéoblastique de calcification vasculaire, con-firme quant à elle les limites de ces gammas caméras en quantification, en lien notamment avec leur faible résolution, sensibilité, et rapport signal sur bruit ne permettant pas une mesure fiable de l’activité de cibles de petites tailles

SPECT/CT CZT camera and absolute quantification in cardiovascular imaging

L’objectif de ce travail de thèse était d’étudier les performances de la gamma camera à semi-conducteur « grand champ » (DNM 670 CZT, GE Healthcare) de dernière génération, en réalisant des études fantômes et cliniques, et en la comparant à la caméra CZT dédié à la cardiologie (DNM 530c, GE Healthcare) et à une gamma caméra conventionnelle (INTEVO BOLD, Siemens Healthcare). Nous nous sommes particulièrement intéressés à la quantification absolue, et avons testé les limites de cette gamma caméra par différentes études fantômes.Malgré d’excellentes performances techniques, la caméra CZT « grand champ » souffre d’une moins bonne sensibilité comparativement à la caméra CZT dédié, qui est optimisée pour l’acquisition myocardique grâce à la configuration cardiofocale de ses détecteurs.La quantification absolue de l’activité radioactive grâce aux camera CZT est performante, et réali-sable en routine. Une première application clinique dans le diagnostic de l’amylose cardiaque ATTR montre des résultats extrêmement prometteurs. La mesure de la charge amyloïde par la fixation des biphosphonate-99mTc sur le myocarde semble fiable et pertinente. Nos études fan-tômes portant sur la mesure théorique de l’activité ostéoblastique de calcification vasculaire, con-firme quant à elle les limites de ces gammas caméras en quantification, en lien notamment avec leur faible résolution, sensibilité, et rapport signal sur bruit ne permettant pas une mesure fiable de l’activité de cibles de petites tailles.This work evaluated the performances of a new polyvalent whole body SPECT/CT CZT camera (DNM 670 CZT GE Healthcare ) compared with a cardiac dedicated CZT camera (DNM 530c GE Healthcare) and with an anger camera (INTEVO BOLD, Siemens Healthcare). We made phantom experiments and clinical studies, with particular interest in quantification.Despite excellent performance, the whole body SPECT/CT CZT camera has a low sensitivity compared to the dedicated CZT camera. This is likely due to the differences in detection geome-try (parallel versus multipinhole collimators).Quantification with whole body SPECT/CT CZT camera is feasible and reliable. We demonstrated the feasibility of 99mTc- HMDP quantitative measurement in patients with suspected cardiac ATTR.We investigated the feasibility and performance of this new CZT camera to quantify osteogenic activity in vascular or valvular calcification with a phantom study. It confirmed the limits of SPECT imaging to measure precisely small target, particularly related to poor sensitivity, noise to background ratio and resolution, responsible of partial volume effect

Deleterious effect of right ventricular pacing in patients with cardiac transthyretin amyloidosis: potential clinical benefit of cardiac resynchronization therapy

International audienceBackground Cardiac amyloidosis involvement is associated with a detrimental outcome including frequent arrhythmias, heart failure, and conduction disturbances which may need permanent pacing. Cases summary We report two cases of patients with transthyretin amyloidosis (ATTR) who developed heart failure and depressed left ventricular ejection fraction (LVEF) following permanent right ventricular (RV) pacing but highly responded to cardiac resynchronization therapy (CRT). Discussion The impact of RV pacing and CRT in cardiac amyloidosis is not known. In our cases, the detrimental effect of permanent RV pacing on left ventricular (LV) systolic function and heart failure symptoms was suggested by both permanent RV pacing mediated functional and LV function decline and LV systolic dysfunction reversal following CRT along with QRS width reduction. Whether cardiac resynchronization should be readily recommended in ATTR patients who need ventricular pacing whatever the LVEF deserves further investigation

First assessment of simultaneous dual isotope (123I/99mTc) cardiac SPECT on two different CZT cameras: A phantom study

International audienceWe studied the impact of simultaneous dual-isotope acquisition on 123I/99mTc mismatch assessment using two CZT cameras (DNM 530c, GE Healthcare and DSPECT, Biosensors International)

Left ventricular function assessment using 123I/99mTc dual-isotope acquisition with two semi-conductor cadmium–zinc–telluride (CZT) cameras: a gated cardiac phantom study

International audienceBACKGROUND:The impact of increased energy resolution of cadmium-zinc-telluride (CZT) cameras on the assessment of left ventricular function under dual-isotope conditions (99mTc and 123I) remains unknown. The Amsterdam-gated dynamic cardiac phantom (AGATE, Vanderwilt techniques, Boxtel, The Netherlands) was successively filled with a solution of 123I alone, 99mTc alone, and a mixture of 123I and 99mTc. A total of 12 datasets was acquired with each commercially available CZT camera (DNM 530c, GE Healthcare and DSPECT, Biosensors International) using both energy windows (99mTc or 123I) with ejection fraction set to 33, 45, and 60 %. End-diastolic (EDV) and end-systolic (ESV) volumes, ejection fraction (LVEF), and regional wall motion and thickening (17-segment model) were assessed using Cedars-Sinai QGS Software. Concordance between single- and dual-isotope acquisitions was tested using Lin's concordance correlation coefficient (CCC) and Bland-Altman plots.RESULTS:There was no significant difference between single- or simultaneous dual-isotope acquisition (123I and 99mTc) for EDV, ESV, LVEF, or segmental wall motion and thickening. Myocardial volumes using single- (123I, 99mTc) and dual-isotope (reconstructed using both 123I and 99mTc energy windows) acquisitions were, respectively, the following: EDV (mL) 88 ± 27 vs. 89 ± 27 vs. 92 ± 29 vs. 90 ± 26 for DNM 530c (p = NS) and 82 ± 20 vs. 83 ± 22 vs. 79 ± 19 vs. 77 ± 20 for DSPECT (p = NS); ESV (mL) 40 ± 1 vs. 41 ± 2 vs. 41 ± 2 vs. 42 ± 1 for DNM 530c (p = NS) and 37 ± 5 vs. 37 ± 1 vs. 35 ± 3 vs. 34 ± 2 for DSPECT (p = NS); LVEF (%) 52 ± 14 vs. 51 ± 13 vs. 53 ± 13 vs. 51 ± 13 for DNM 530c (p = NS) and 52 ± 16 vs. 54 ± 13 vs. 54 ± 14 vs. 54 ± 13 for DSPECT (p = NS); regional motion (mm) 6.72 ± 2.82 vs. 6.58 ± 2.52 vs. 6.86 ± 2.99 vs. 6.59 ± 2.76 for DNM 530c (p = NS) and 6.79 ± 3.17 vs. 6.81 ± 2.75 vs. 6.71 ± 2.50 vs. 6.62 ± 2.74 for DSPECT (p = NS). The type of camera significantly impacted only on ESV (p < 0.001).CONCLUSIONS:The new CZT cameras yielded similar results for the assessment of LVEF and regional motion using different energy windows (123I or 99mTc) and acquisition types (single vs. dual). With simultaneous dual-isotope acquisitions, the presence of 123I did not impact on LVEF assessment within the 99mTc energy window for either CZT camera

Determination of the Heart-to-Mediastinum Ratio of 123 I-MIBG Uptake Using Dual-Isotope ( 123 I-MIBG/ 99m Tc-Tetrofosmin) Multipinhole Cadmium-Zinc-Telluride SPECT in Patients with Heart Failure

International audienceThe aim of this retrospective study was to compare the heart-to-mediastinum ratio (HMR) of123I-metaiodobenzylguanidine (123I-MIBG) uptake obtained using a multipinhole cadmium-zinc-telluride (CZT) camera with that obtained using conventional planar imaging.Methods:Forty consecutive heart failure patients underwent planar acquisition 4 h after123I-MIBG injection (191 ± 41 [mean ± SD] MBq). To localize the heart using the CZT camera,99mTc-tetrofosmin (358 ± 177 MBq) was administered and dual-isotope acquisition was performed. The HMRs were calculated with conventional planar imaging (HMRplanar), with anterior reprojection images using the CZT camera (HMRreproj), and with transaxial reconstructed images using the CZT camera (HMRtransaxial). In a phantom study, we estimated a linear model fitting the CZT camera data to the planar data, and we applied it to provide corrected CZT camera-determined HMRs in patients (cHMRreprojand cHMRtransaxial).Results:Thirty-four men and 6 women (71 ± 9 y old) with ischemic (22 patients) and nonischemic (18 patients) heart failure completed the study. For 22 of the 40 patients (55%), the New York Heart Association classification was class II and the ejection fraction was 35% ± 9%. HMRreproj(1.12 ± 0.19) and HMRtransaxial(1.35 ± 0.34) were lower than HMRplanar(1.44 ± 0.14) (P< 0.0001 andP< 0.01, respectively). cHMRreproj(1.54 ± 0.09) and cHMRtransaxial(1.45 ± 0.14) were significantly different (P< 0.0001). Lin concordance correlation and Bland-Altman analysis demonstrated an almost perfect concordance and a high agreement between HMRplanarand cHMRtransaxial(Pwas not significant) but not between HMRplanarand cHMRreproj(P< 0.0001).Conclusion:This study demonstrated that determination of the late HMR of cardiac123I-MIBG uptake using dual-isotope (123I and99mTc) acquisition on a multipinhole CZT camera was feasible in patients with heart failure. However, this determination should be performed using transaxial reconstructed images and linear correction based on phantom data acquisitions

Quantitation of myocardial 99mTc-HMDP uptake h new SPECT/CT Cadmium zinc telluride (CZT) camera in patients `th transthyretin-related cardiac amyloidosis: ready for clinical use?

Annual Meeting of the Society-of-Nuclear-Medicine-and-Molecular-Imaging (SNMMI), Anaheim, CA, JUN 22-25, 2019International audienc

Hyperglycemia-Induced Hypovolemia Is Involved in Early Cardiac Magnetic Resonance Alterations in Streptozotocin-Induced Diabetic Mice: A Comparison with Furosemide-Induced Hypovolemia

<div><p>Aims</p><p>The aim of the study was to assess the early features of diabetic cardiomyopathy using cardiac magnetic resonance within the first week after streptozotocin injection in mice. We focused on the relationship between left ventricular function and hypovolemia markers in diabetic animals compared to a hypovolemic rodent model.</p><p>Methods and Results</p><p>Swiss mice were randomized into control (group C), streptozotocin-induced diabetes (group D) and furosemide-induced hypovolemia (group F) groups. Cardiac magnetic resonance, non-invasive blood pressure, urine volume, plasma markers of dehydration and cardiac histology were assessed in all groups. Mean blood glucose was higher in diabetic animals than in groups C and F (30.5±5.8 compared to 10.4±2.1 and 11.1±2.8 mmol/L, respectively; p<0.01). Diuresis was increased in animals from group D and F compared to C (14650±11499 and 1533±540 compared to 192±111 μL/24 h; p<0.05). End diastolic and end systolic volumes were lower in group D than in group C at week 1 (1.52±0.36 vs. 1.93±0.35 and 0.54±0.22 vs. 0.75±0.18 mL/kg, p<0.05). These left ventricular volume values in group D were comparable to those observed in the acute hypovolemia model (group F). Increased dehydration plasma markers and an absence of obvious intrinsic myocardial damage (evaluated by cardiac magnetic resonance and histology) suggest that a hemodynamic mechanism underlies the very early drop in left ventricular volumes in group D and provides a potential link to hyperglycemic osmotic diuresis.</p><p>Conclusions</p><p>Researchers using cardiac magnetic resonance in hyperglycemic rodent models should be aware of this hemodynamic mechanism, which may partially explain modifications in cardiac parameters in addition to diabetic myocardial damage.</p></div