Differences in the performance of cadmium-zinc-telluride (CZT) cameras or collimation systems that have recently been commercialized for myocardial SPECT remain unclear. In the present study, the performance of 3 of these systems was compared by a comprehensive analysis of phantom and human SPECT images. Methods: We evaluated the Discovery NM 530c and DSPECT CZT cameras, as well as the Symbia Anger camera equipped with an astigmatic (IQÁSPECT) or parallel-hole (conventional SPECT) collimator. Physical performance was compared on reconstructed SPECT images from a phantom and from comparable groups of healthy subjects. Results: Classifications were as follows, in order of performance. For count sensitivity on cardiac phantom images (countsÁs 21 ÁMBq 21 ), DSPECT had a sensitivity of 850; Discovery NM 530c, 460; IQÁSPECT, 390; and conventional SPECT, 130. This classification was similar to that of myocardial counts normalized to injected activities from human images (respective mean values, in countsÁs 21 ÁMBq 21 : 11.4 6 2.6, 5.6 6 1.4, 2.7 6 0.7, and 0.6 6 0.1). For central spatial resolution: Discovery NM 530c was 6.7 mm; DSPECT, 8.6 mm; IQÁSPECT, 15.0 mm; and conventional SPECT, 15.3 mm, also in accordance with the analysis of the sharpness of myocardial contours on human images (in cm 21 : 1.02 6 0.17, 0.92 6 0.11, 0.64 6 0.12, and 0.65 6 0.06, respectively). For contrast-to-noise ratio on the phantom: Discovery NM 530c had a ratio of 4.6; DSPECT, 4.1; IQÁSPECT, 3.9; and conventional SPECT, 3.5, similar to ratios documented on human images (5.2 6 1.0, 4.5 6 0.5, 3.9 6 0.6, and 3.4 6 0.3, respectively). Conclusion: The performance of CZT cameras is dramatically higher than that of Anger cameras, even for human SPECT images. However, CZT cameras differ in that spatial resolution and contrast-to-noise ratio are better with the Discovery NM 530c, whereas count sensitivity is markedly higher with the DSPECT.Key Words: CZT-cameras; high-speed SPECT; myocardial perfusion imaging; count sensitivity St ress myocardial SPECT has been markedly enhanced by the recent commercialization of cameras with semiconductor (cadmium-zinc-telluride [CZT]) detectors or new collimation systems. These improved systems enhance the sensitivity of count detection and thereby enable recording times or tracer doses to be reduced, a property that has highly favorable consequences on patient comfort and radiation exposure (1-4). This enhancement is based mainly on acquisitions that are heart-centric but obtained with very different technologies: first, for the IQÁSPECT system (Siemens Medical Solutions (5-8)), an Anger camera equipped with collimators convergent on the image center (astigmatic collimators); second, for the DSPECT system (Spectrum Dynamics (9-13)), mobile columns of CZT detectors with wide parallel-hole collimators; and third, for the Discovery NM 530c system (GE Healthcare (14-21)), fixed CZT detectors with multipinhole collimators.The respective performance of these new cameras and collimation systems has been analyzed, but ...

Abstract-Carotid-femoral pulse wave velocity (PWV) is considered the gold-standard measurement of arterial stiffness.Obesity, however, can render inaccurate the measurement of PWV by external noninvasive devices. Phase-contrast MRI allows the determination of aortic PWV in multiple aortic locations with intra-arterial distance measurements, as well as the assessment of aortic mechanical properties. Key Words: arterial stiffness Ⅲ pulse wave velocity Ⅲ obesity Ⅲ MRI Ⅲ aortic distensibility A rterial stiffness assessed by pulse wave velocity (PWV) measurement is now well accepted as an independent predictor of cardiovascular mortality and morbidity. 1 Rapid and reproducible external noninvasive methods are the gold standard for measuring PWV by recording the pressure waves at respective carotid and femoral sites. 2 Several recent studies have indicated an effect of obesity on arterial stiffness, especially when associated with metabolic disorders. [3][4][5] Therefore, measurements of PWV in overweight and obese subjects may be of major interest in assessing cardiovascular risk. However, obesity is a well known factor of technical operator bias when assessing PWV. 2,6 This concerns both difficulties in obtaining pressure curves of good quality and technical difficulties in measuring distance. In this context, PWV assessment is questionable in overweight and obese subjects [2][3][4]6,7 ; therefore, a comparison between external PWV-recording transcutaneous devices and internal noninvasive methods, eg, phase-contrast MRI, could prove valuable, while also providing morphological information. 8 -10 In fact, the acquisition of cross-sectional MRI aortic vascular structural indices, provided by combined high spatial and temporal resolutions, should not be affected by either body composition or imaging plane.The current study was designed to assess the relationship between PWV values obtained with 2 well-validated transcutaneous devices (Complior II and PulsePen) and MRI acquisition of PWV along with aortic cross-sectional mechanical properties estimated by aortic distensibility and compliance, aortic elastic modulus, and stiffness index in a population presenting isolated abdominal obesity considered to reflect a high disease risk and defined by a waist circumference Ͼ102 cm for men and Ͼ88 cm for women in overweight and obese patients (body mass index from 27 to 35 kg m Ϫ2 ). Methods Subject SelectionEighteen male and 14 female subjects presenting with isolated abdominal obesity were prospectively recruited by local press

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