المؤلفون: Alessandro Desy, Guillaume F. Bouvet, Étienne Croteau, Nancy Lafrenière, Éric E. Turcotte, Philippe Després, Jean-Mathieu Beauregard

المصدر: EJNMMI Physics, Vol 8, Iss 1, Pp 1-11 (2021)

مصطلحات موضوعية: Quantitative SPECT, SPECT/CT, Calibration, Dead time, High count rate, Medical physics. Medical radiology. Nuclear medicine, R895-920

الوصف: Abstract Background Accurate QSPECT is crucial in dosimetry-based, personalized radiopharmaceutical therapy with 177Lu and other radionuclides. We compared the quantitative performance of three NaI(Tl)-crystal SPECT/CT systems equipped with low-energy high-resolution collimators from two vendors (Siemens Symbia T6; GE Discovery 670 and NM/CT 870 DR). Methods Using up to 14 GBq of 99mTc in planar mode, we determined the calibration factor and dead-time constant under the assumption that these systems have a paralyzable behaviour. We monitored their response when one or both detectors were activated. QSPECT capability was validated by SPECT/CT imaging of a customized NEMA phantom containing up to 17 GBq of 99mTc. Acquisitions were reconstructed with a third-party ordered subset expectation maximization algorithm. Results The Siemens system had a higher calibration factor (100.0 cps/MBq) and a lower dead-time constant (0.49 μs) than those from GE (75.4–87.5 cps/MBq; 1.74 μs). Activities of up to 3.3 vs. 2.3–2.7 GBq, respectively, were quantifiable by QSPECT before the observed count rate plateaued or decreased. When used in single-detector mode, the QSPECT capability of the former system increased to 5.1 GBq, whereas that of the latter two systems remained independent of the detectors activation mode. Conclusion Despite similar hardware, SPECT/CT systems’ response can significantly differ at high count rate, which impacts their QSPECT capability in a post-therapeutic setting.

وصف الملف: electronic resource

Relation: https://doaj.org/toc/2197-7364

URL الوصول: https://doaj.org/article/96054f52ec204390bc21a7c26411be58

المؤلفون: Marc-André d’Entremont, Gabriel Fortin, Thao Huynh, Étienne Croteau, Paul Farand, Samuel Lemaire-Paquette, Marie-Claude Brochu, Doan Hoa Do, Serge Lepage, Warner Mbuila Mampuya, Étienne L. Couture, Michel Nguyen, Btissama Essadiqi

المصدر: Cardiovascular Ultrasound, Vol 19, Iss 1, Pp 1-11 (2021)

مصطلحات موضوعية: Coronary artery disease, Exercise stress echocardiography, Speckle-tracking, Strain-imaging, Diseases of the circulatory (Cardiovascular) system, RC666-701

الوصف: Abstract Background Two-dimensional speckle-tracking echocardiography (STE) may help detect coronary artery disease (CAD) when combined with dobutamine stress echocardiography. However, few studies have explored STE with exercise stress echocardiography (ESE). We aimed to evaluate the feasibility, reliability, and incremental value of STE combined with treadmill ESE compared to treadmill ESE alone to detect CAD. Methods We conducted a case–control study of all consecutive patients with abnormal ESE in 2018–2020 who subsequently underwent coronary angiography within a six-month interval. We 1:1 propensity score-matched these patients to those with a normal ESE. Two blinded operators generated a 17-segment bull's-eye map of longitudinal strain (LS). We utilized the mean differences between stress and baseline LS values in segments 13–17, segment 17, and segments 15–16 to create receiver operator curves for the overall examination, the left anterior descending artery (LAD), and the non-LAD territories, respectively. Results We excluded 61 STEs from 201 (30.3%) eligible ESEs; 47 (23.4%) because of suboptimal image quality and 14 (7.0%) because of excessive heart rate variability precluding the calculation of a bull's-eye map. After matching, a total of 102 patients were included (51 patients in each group). In the group with abnormal ESE patients (mean age 66.4 years, 39.2% female), 64.7% had significant CAD (> 70% stenosis) at coronary angiogram. In the group with normal ESE patients (mean age 65.1 years, 35.3% female), 3.9% were diagnosed with a new significant coronary stenosis within one year. The intra-class correlation for global LS was 0.87 at rest and 0.92 at stress, and 0.84 at rest, and 0.89 at stress for the apical segments. The diagnostic accuracy of combining ESE and STE was superior to visual assessment alone for the overall examination (area under the curve (AUC) = 0.89 vs. 0.84, p = 0.025), the non-LAD territory (AUC = 0.83 vs. 0.70, p = 0.006), but not the LAD territory (AUC = 0.79 vs. 0.73, p = 0.11). Conclusions Two-dimensional speckle-tracking combined with treadmill ESE is relatively feasible, reliable, and may provide incremental diagnostic value for the detection and localization of significant CAD.

وصف الملف: electronic resource

Relation: https://doaj.org/toc/1476-7120

URL الوصول: https://doaj.org/article/f1fe81379fa04f1fbf48f69e37c5f1ac

المؤلفون: Abdelillah Douhi, Mamdouh S. Al‑enezi, Nousra Berrahmoune, Abdelouahed Khalil, Tamas Fulop, Michel Nguyen, Eric Turcotte, Étienne Croteau, M’hamed Bentourkia

المصدر: Physical and Engineering Sciences in Medicine. 46:295-302

مصطلحات موضوعية: Radiological and Ultrasound Technology, Biomedical Engineering, Biophysics, Radiology, Nuclear Medicine and imaging, Instrumentation, Biotechnology

URL الوصول: https://explore.openaire.eu/search/publication?articleId=doi_________::e477570927ce91a4ae83dade8cd7939c
https://doi.org/10.1007/s13246-023-01218-7

المؤلفون: Éric, Poulin, Réjean, Lebel, Étienne, Croteau, Marie, Blanchette, Luc, Tremblay, Roger, Lecomte, M'hamed, Bentourkia, Martin, Lepage

المصدر: Magnetic resonance in medicine. 73(2)

مصطلحات موضوعية: Gadolinium DTPA, Brain Neoplasms, Contrast Media, Reproducibility of Results, Image Enhancement, Magnetic Resonance Imaging, Models, Biological, Multimodal Imaging, Sensitivity and Specificity, Rats, Inbred F344, Fluorodeoxyglucose F18, Reference Values, Cell Line, Tumor, Positron-Emission Tomography, Image Interpretation, Computer-Assisted, Animals, Radiopharmaceuticals, Glioblastoma

الوصف: The combination of MRI and positron emission tomography (PET) offers new possibilities for the development of novel methodologies. In pharmacokinetic image analysis, the blood concentration of the imaging compound as a function of time, [i.e., the arterial input function (AIF)] is required for MRI and PET. In this study, we tested whether an AIF extracted from a reference region (RR) in MRI can be used as a surrogate for the manually sampled (18) F-FDG AIF for pharmacokinetic modeling.An MRI contrast agent, gadolinium-diethylenetriaminepentaacetic acid (Gd-DTPA) and a radiotracer, (18) F-fluorodeoxyglucose ((18) F-FDG), were simultaneously injected in a F98 glioblastoma rat model. A correction to the RR AIF for Gd-DTPA is proposed to adequately represent the manually sampled AIF. A previously published conversion method was applied to convert this AIF into a (18) F-FDG AIF.The tumor metabolic rate of glucose (TMRGlc) calculated with the manually sampled (18) F-FDG AIF, the (18) F-FDG AIF converted from the RR AIF and the (18) F-FDG AIF converted from the corrected RR AIF were found not statistically different (P0.05).An AIF derived from an RR in MRI can be accurately converted into a (18) F-FDG AIF and used in PET pharmacokinetic modeling.

URL الوصول: https://explore.openaire.eu/search/publication?articleId=pmid________::a66d61dc8852558b4ff73b852b94607c
https://pubmed.ncbi.nlm.nih.gov/24604379

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