Mitsuaki Tatsumi MD, PhD, Presenter: Nothing to Disclose

Seiichi Yamamoto, Abstract Co-Author: Nothing to Disclose

Masao Imaizumi, Abstract Co-Author: Nothing to Disclose

Yasukazu Kanai, Abstract Co-Author: Nothing to Disclose

Eku Shimosegawa, Abstract Co-Author: Nothing to Disclose

Jun Hatazawa MD, PhD, Abstract Co-Author: Nothing to Disclose

We developed a fully integrated (i) PET/MRI system for small animal imaging. The purpose of this study was to demonstrate simultaneous PET and MR in vivo rat imaging with various tracers using this system.

The iPET/MRI system consists of DOI block detectors made of LGSO, optical fibers (~80cm), PSPMTs for PET, RF coil (φ7.6cm) and 0.3T Nd-Fe-B permanent magnet for MRI. As a PET tracer, F-18 FDG, F-18 NaF or C-11 Methionine (MET) was injected i.v. to each rat under isoflurane anesthesia, with or without Gadoxetate (Gd-EOB-DTPA) for contrast-enhanced MRI. PET (list mode) and MR (fast low angle shot T1-weighted sequence, TR/TE=50/5msec) imaging was performed at appropriate time points from head to abdomen. During MRI acquisition, PET data were acquired in 3 axial position by moving the PET detector ring to cover ~5cm axial FOV. PET, MRI, and co-registered fusion images were evaluated regarding image quality and feasibility for rat imaging.

Simultaneous PET/MR imaging was successfully performed with good image quality. Among normal organs and structures observed in rats, FDG uptake was especially identified in the cerebral basal ganglia, harderian glands, brown fat, myocardium (right and left ventricles separately), and kidneys, which were also depicted on MRI. NaF PET/MRI clearly demonstrated each spine separately. CE MRI with EOB represented relatively high signal intensity in the liver and kidneys, providing excellent mapping images. Intense MET uptake was observed in the liver and pancreas on PET, both of which were well recognized on MR and fusion images.

Simultaneous PET and MR imaging with an iPET/MRI system was demonstrated to be a feasible and promising technique for rat imaging studies. <Research Support: Program for Promotion of Fundamental Studies in Health Sciences of the National Institute of Biomedical Innovations (No. 06-35)>.

This rodent study suggested promise of simultaneous PET and MR imaging with various tracers using an integrated PET/MRI system in clinical studies.

Tatsumi, M, Yamamoto, S, Imaizumi, M, Kanai, Y, Shimosegawa, E, Hatazawa, J, Simultaneous PET and MR Imaging in Rat: Initial Experience with an Integrated PET/MRI System.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8011522.html