High-field PET/MRI and MRS: Potential clinical and research applications

Abstract

Nowadays hybrid PET/MRI systems and magnetic resonance spectroscopy (MRS) with high field strength are becoming more widespread not only in research applications but also in clinical practice. The aim of this paper is to review the current roles of high-field PET/MRI and high-field magnetic resonance spectroscopy (MRS) in the clinical setting and their applications in research. A non-systematic literature search of the Medline and Cochrane Library databases was performed up to September 2012. Bibliographies of retrieved articles and review articles were also examined. Only those articles reporting complete data of clinical and research relevance for the present review (i.e., diagnosis, therapeutic response monitoring) were selected. The advent of higher field strengths (3-T and above), and thus, higher spectral resolution, increased the potentiality and the diffusion of MRS evaluations. This review article is divided into two major parts. The first considers the potential clinical and research roles of MRS at 3-T and of hybrid system PET/MRI, particularly with regard to simultaneous PET/MRI systems which provide some major advantages over the conventional PET/CT systems (such as identical position of the patient during image acquisition, no radiation burden from the MRI part, more structural, functional and molecular imaging at the same time). The second part provides detailed information about the use of ultra-high-field MRS and MRI (7-T) integrated with PET. The fusion of biological information (PET) and morpho-metabolic patterns (MRI-MRS) shows promise for obtaining early diagnosis, coherent follow-up and the desired response to therapy. © 2013 Italian Association of Nuclear Medicine and Molecular Imaging.