First imaging results obtained with a multimodal apparatus combining low-field (35.7 mT) MRI and pulsed EPRI.

Nuclear magnetic resonance imaging (MRI) provides excellent images of organs and is an essential diagnostic tool in the medical field. Electron paramagnetic resonance imaging (EPRI) is being increasingly used in the biomedical field because of recent hardware advances. We present the first images obtained with a low-field (35.7 mT) multimodal apparatus that combines MRI and pulsed EPRI. For this purpose, the sample is composed of two sections, one sensitive to MRI and the other sensitive to EPRI. The MRI section of the sample is composed of three tubes containing 7 ml of a 10 mM CuSO4 water solution. The EPR section of the sample is composed of two tubes containing 350 mg of lithium phthalocyanine. The EPR image represents the two-dimensional projection of the whole sample and is reconstructed from 32 one-dimensional projections by using the Fourier reconstruction method. The MRI image is obtained by selecting a sample slice, 10 mm in thickness, by using a spin-echo sequence and the two-dimensional fast Fourier transform. The experimental results obtained with this apparatus show that the spatial resolution is better than 1 mm for the MRI section and better than 7 mm for the EPRI section. The measured SNR of the MRI and EPRI images were about 60 and 160, respectively. A detailed description of the hardware, pulse sequences and image reconstruction techniques is reported.