Small-animal SPECT and SPECT/CT: application in cardiovascular research

Abstract

Preclinical cardiovascular research using noninvasive radionuclide and hybrid imaging systems has been extensively developed in recent years. Single photon emission computed tomography (SPECT) is based on the molecular tracer principle and is an established tool in noninvasive imaging. SPECT uses gamma cameras and collimators to form projection data that are used to estimate (dynamic) 3-D tracer distributions in vivo. Recent developments in multipinhole collimation and advanced image reconstruction have led to sub-millimetre and sub-half-millimetre resolution SPECT in rats and mice, respectively. In this article we review applications of microSPECT in cardiovascular research in which information about the function and pathology of the myocardium, vessels and neurons is obtained. We give examples on how diagnostic tracers, new therapeutic interventions, pre- and postcardiovascular event prognosis, and functional and pathophysiological heart conditions can be explored by microSPECT, using small-animal models of cardiovascular disease.

Fig. 1

a) Separate U-CT system and U-SPECT-II system. b) Integrated U-SPECT-II/CT system

Fig. 2

U-SPECT gated mouse cardiac perfusion images obtained in a normal C57BL/6 mouse (ED end diastole, ES end systole)

Fig. 3

Uptake of RP805 (a broad-spectrum MMP ligand) demonstrating MMP expression in an atherosclerotic rabbit on an uninterrupted diet. The three columns display transverse, sagittal, and frontal projections, and the three rows display microCT, microSPECT, and fusion images. The left set of three columns displays images immediately (0 h) after radiotracer administration (representing blood pool images), and the right set of three columns displays images obtained at 4 h (representing tracer uptake in target tissue). The images were adapted from reference [74]