MRI-Driven PET Image Optimization for Neurological Applications

Abstract

Positron emission tomography (PET) and magnetic resonance imaging (MRI) are established imaging modalities for the study of neurological disorders, such as epilepsy, dementia, psychiatric disorders and so on. Since these two available modalities vary in imaging principle and physical performance, each technique has its own advantages and disadvantages over the other. To acquire the mutual complementary information and reinforce each other, there is a need for the fusion of PET and MRI. This combined dual-modality (either sequential or simultaneous) could generate preferable soft tissue contrast of brain tissue, flexible acquisition parameters, and minimized exposure to radiation. The most unique superiority of PET/MRI is mainly manifested in MRI-based improvement for the inherent limitations of PET, such as motion artifacts, partial volume effect (PVE) and invasive procedure in quantitative analysis. Head motion during scanning significantly deteriorates the effective resolution of PET image, especially for the dynamic scan with lengthy time. Hybrid PET/MRI device can offer motion correction (MC) for PET data through MRI information acquired simultaneously. Regarding the PVE associated with limited spatial resolution, the process and reconstruction of PET data can be further optimized by using acquired MRI either sequentially or simultaneously. The quantitative analysis of dynamic PET data mainly relies upon an invasive arterial blood sampling procedure to acquire arterial input function (AIF). An image-derived input function (IDIF) method without the need of arterial cannulization, can serve as a potential alternative estimation of AIF. Compared with using PET data only, combining anatomical or functional information from MRI for improving the accuracy in IDIF approach has been demonstrated. Yet, due to the interference and inherent disparity between the two modalities, these methods for optimizing PET image based on MRI still have many technical challenges. This review discussed upon the most recent progress, current challenges and future directions of MRI-driven PET data optimization for neurological applications, with either sequential or simultaneous acquisition approach.

Magnetic Resonance-Based Attenuation Correction and Scatter Correction in Neurological Positron Emission Tomography/Magnetic Resonance Imaging—Current Status With Emerging Applications

“…Using an image-derived input function (IDIF) for kinetic modeling on PET/MRI will certainly benefit from accurate data corrections and will be further improved by the complementary nature of both modalities. MRI data could be used to assist and complement PET data in several ways [188]. Using TOF MR angiography can improve the delineation of the arterial volume in PET [184,[189][190][191].…”

Utility of hybrid PET/MRI multiparametric imaging in navigating SEEG placement in refractory epilepsy

“…However, co-registered PET and MRI obtained with separate PET/CT and MRI imaging presents difficulty for precise registration and additional exposure to radiation by CT. Recently, some studies showed that a hybrid PET and MRI system minimized patient discomfort while maximizing clinical information and optimizing the use of both modalities [6,8,10,26].…”

The Added Value of Diagnostic and Theranostic PET Imaging for the Treatment of CNS Tumors

“…Although morphological MRI is the current standard of care for the diagnostic workup, treatment planning, response monitoring, and surveillance during follow-up of CNS tumors, we envision that PET imaging will gain more and more ground in the next years because of the rapid development of promising diagnostic and especially theranostic tracers [47,150,151]. Molecular PET imaging enables non-invasive CNS tumor diagnostics, which is potentially useful for studies into cancer genetic diversity and cancer evolution over time and space.…”