Comparison of 4D-MicroSPECT and MicroCT for Murine Cardiac Function

Abstract

Purpose The objective of this study was to compare a new generation of four-dimensional (4D) microSPECT with microCT for quantitative in vivo assessment of murine cardiac function. Procedures 4D isotropic cardiac images were acquired from normal C57BL/6 mice with either microSPECT at 350-micron resolution (n=6) or microCT at 88-micron resolution (n=6). One additional mouse with myocardial infarction (MI) was scanned with both modalities. Prior to imaging, mice were injected with either 99mTc -tetrofosmin for microSPECT, or a liposomal blood pool contrast agent for microCT. Segmentation of the left ventricle (LV) was performed using Vitrea (Vital Images) software, to derive global and regional function. Results Measures of global LV function between microSPECT and microCT groups were comparable (e.g. ejection fraction=71±6%-microSPECT and 68±4%-microCT). Regional functional indices (wall motion, wall thickening, regional ejection fraction) were also similar for the two modalities. In the mouse with MI, microSPECT identified a large perfusion defect that was not evident with microCT. Conclusions Despite lower spatial resolution, microSPECT was comparable to microCT in the quantitative evaluation of cardiac function. MicroSPECT offers an advantage over microCT in the ability to evaluate myocardial perfusion radiotracer distribution and function simultaneously. MicroSPECT should be considered as an alternative to microCT and MR for preclinical cardiac imaging in the mouse.

Numerical simulation of novel concept 4D cardiac microtomography for small rodents based on all-optical Thomson scattering X-ray sources

“…The estimated radiation dose after 12000x-ray pulses generated during the simulated retrospectively gated acquisition was . This value is comparable to or lower than doses reported on similar works using conventional sources 9,47–49 . Even though the focus of this paper was not on accurate dosimetry, the GEANT4 simulation toolkit has been already shown to be accurate in dosimetric calculations at low photon energy 50 .…”

“…High temporal resolution modalities such as micro magnetic resonance (micro-MRI) or micro-ultrasonography (micro-US) only allow multi-slice, non-isotropic (stacked 2D) imaging. On the other hand, micro-computed tomography (micro-CT) and micro-single photon emission tomography (micro-SPECT) with double ECG/respiratory gating do allow isotropic fully 3D imaging, even though cine-mode dynamic reconstructions are limited to 10 time frames per cardiac cycle or less 9,10 . In particular, dynamic micro-CT (4D μ CT) appears promising for morphofunctional imaging of the cardiac biomechanics, due to its high spatial resolution and good discrimination of myocardial walls, ventricular cavities and lung tissue upon use of suitable blood-pool contrast agents.…”

Remodeling of alveolar septa after murine pneumonectomy

“…The alveolar diameter of the normal mouse alveolus is 60 m (26), close to the resolution of microCT and nanoCT (3). In contrast, highenergy imaging, such as the synchrotron, provides less than 1-m resolution (29,31).…”

<em>In Vivo</em> Quantitative Assessment of Myocardial Structure, Function, Perfusion and Viability Using Cardiac Micro-computed Tomography

“…In order to enable standardized quantification of the extent and severity of the lesion, wall motion, wall thickening, and regional ejection fractions are commonly mapped into polar maps. Abnormalities of regional ventricular wall motion are important markers of myocardial ischemia that are most commonly assessed by MRI 52 . The LV wall motion, thickening and regional ejection fraction scores for each segment of a mouse with and without myocardial infarction are presented in Figure 9 and Figure 10.…”