PETMRIhen

PETMRIhen is a term used to describe an integrated imaging modality that combines positron emission tomography (PET) with magnetic resonance imaging (MRI). It represents the conceptual and practical fusion of molecular imaging with high-resolution anatomical and functional MRI, enabling simultaneous or near-simultaneous acquisition of metabolic and structural information in a single session.

Practically, PETMRIhen uses a combined scanner capable of simultaneous or near-simultaneous PET and MRI acquisitions. PET detectors are integrated into an MRI-compatible system; MRI provides high-contrast anatomical images and functional sequences, while PET adds metabolic or molecular data. Attenuation correction relies on MRI-derived maps, and time-of-flight technology improves PET sensitivity. Specialized RF coils support signal collection and image quality.

Applications of PETMRIhen span neurology, oncology, and cardiology. In neurology, it supports investigations of neurodegenerative diseases, epilepsy, and inflammatory or demyelinating conditions. In oncology, it aids in tumor characterization, treatment planning, and monitoring for brain, head-and-neck, prostate, and other cancers. In cardiology, it can be used for ischemia assessment and myocardial viability. In research settings, PETMRIhen enables multimodal studies of disease mechanisms, tumor biology, and therapy response.

Advantages of PETMRIhen include improved co-registration of metabolic and anatomical data, enhanced lesion characterization, and reduced radiation exposure relative to PET-CT when MRI is used instead of CT. Limitations encompass high cost and limited availability, increased scan times, complexity of data analysis, MRI-related artifacts, and challenges in MR-based attenuation correction and patient safety around implants.

History and status: Integrated PET-MRI systems began to appear in clinical and research settings in the 2010s. The term PETMRIhen appears in some literature as a descriptive name for this modality but is not a widely standardized designation. Ongoing work focuses on improving attenuation correction, motion management, and workflow efficiency.