Initial Investigation of Preclinical Integrated SPECT and MR Imaging

Abstract

Single-photon emission computed tomography (SPECT) can provide specific functional information while magnetic resonance imaging (MRI) can provide high-spatial resolution anatomical information as well as complementary functional information. In this study, we utilized a dual modality SPECT/MRI (MRSPECT) system to investigate the integration of SPECT and MRI for improved image accuracy. The MRSPECT system consisted of a cadmium-zinc-telluride (CZT) nuclear radiation detector interfaced with a specialized radiofrequency (RF) coil that was placed within a whole-body 4 T MRI system. The importance of proper corrections for non-uniform detector sensitivity and Lorentz force effects was demonstrated. MRI data were utilized for attenuation correction (AC) of the nuclear projection data and optimized Wiener filtering of the SPECT reconstruction for improved image accuracy. Finally, simultaneous dual-imaging of a nude mouse was performed to demonstrated the utility of co-registration for accurate localization of a radioactive source.

Feasibility study of a unilateral RF array coil for MR-scintimammography

“…With RF shielding, the operating MRI system did not adversely affect the measured radiation counts within the ±5% energy window. This finding is consistent with previous combined imaging studies (Hamamura et al 2010a, 2010b). The RF shielding did introduce a shift in the resonance frequency and an increase in the E 1 electric field and SAR at the periphery of the test phantom.…”

“…Co-registered anatomical MR images can provide a reference for the SMM images, allowing for improved localization. The higher spatial resolution MR images can be utilized to improve the spatial resolution of gamma-ray images through post-processing techniques such as the maximization of mutual information (Hamamura et al 2010b). Simultaneous imaging would enable the use of both MRI contrast agents and radiotracers to investigate multiple biological processes at the same time (Hamamura et al 2011).…”

Development and evaluation of a dual-modality (MRI/SPECT) molecular imaging bioprobe

“…With the progress made recently in development of combined PET/MRI and SPECT/MRI scanners, dual-modality imaging agents such as the one developed in the current study have enormous potential to be used in the clinic in the near future. 3,49,50 In conclusion, we successfully developed and tested a novel dual-modality molecular imaging probe for in vivo detection of mesothelin-expressing tumors by both MRI and SPECT. This imaging bioprobe demonstrated better size distribution and relaxivity properties in comparison with the previously developed MRI and SPECT/MRI contrast agents.…”

Perspectives on Small Animal Radionuclide Imaging; Considerations and Advances in Atherosclerosis

“…Use of hybrid systems, providing an anatomical reference by (contrast-enhanced) CT or MRI ( 1 , 2 , 39 , 56 ), are crucial in atherosclerotic mouse studies because the small plaques are located close to other tissues. MRI has the major advantage of providing soft tissue contrast, which is crucial to distinguish arteries from surrounding tissue.…”