Learn More
Magnetic resonance imaging (MRI) is a widely used method for non-invasive study of the structure and function of the human brain. Increasing magnetic field strengths enable higher resolution imaging; however, long scan times and high motion sensitivity mean that image quality is often limited by the involuntary motion of the subject. Prospective motion(More)
Motion correction in magnetic resonance imaging by real-time adjustment of the imaging pulse sequence was first proposed more than 20 years ago. Recent advances have resulted from combining real-time correction with new navigator and external tracking mechanisms capable of quantifying rigid-body motion in all 6 degrees of freedom. The technique is now often(More)
OBJECTIVE We aimed to test the hypothesis that slice-by-slice prospective motion correction at 7T using an optical tracking system reduces the rate of false positive activations in an fMRI group study with a paradigm that involves task-correlated motion. MATERIALS AND METHODS Brain activation during right leg movement was measured using a block design on(More)
OBJECT Prospective motion correction using data from optical tracking systems has been previously shown to reduce motion artifacts in MR imaging of the head. We evaluate a novel optical embedded tracking system. MATERIALS AND METHODS The home-built optical embedded tracking system performs image processing within a 7 T scanner bore, enabling high speed(More)
PURPOSE Despite numerous publications describing the ability of prospective motion correction to improve image quality in magnetic resonance imaging of the brain, a reliable approach to assess this improvement is still missing. A method that accurately reproduces motion artifacts correctable with prospective motion correction is developed, and enables the(More)
PURPOSE The goal of this study was to compare the accuracy of two real-time motion tracking systems in the MR environment: MR-based prospective motion correction (PROMO) and optical moiré phase tracking (MPT). METHODS Five subjects performed eight predefined head rotations of 8° ± 3° while being simultaneously tracked with PROMO and MPT. Structural images(More)
OBJECT State-of-the-art MR techniques that rely on echo planar imaging (EPI), such as real-time fMRI, are limited in their applicability by both subject motion and B(0) field inhomogeneities. The goal of this work is to demonstrate that in principle it is possible to accurately predict the B(0) field inhomogeneities that occur during echo planar imaging in(More)
Despite the existence of numerous motion correction methods, head motion during MRI continues to be a major source of artifacts and can greatly reduce image quality. This applies particularly to diffusion weighted imaging, where strong gradients are applied during long encoding periods. These are necessary to encode microscopic movements. However, they also(More)
Evaluation of neurodegenerative disease progression may be assisted by quantification of the volume of structures in the human brain using magnetic resonance imaging (MRI). Automated segmentation software has improved the feasibility of this approach, but often the reliability of measurements is uncertain. We have established a unique dataset to assess the(More)
Prospective motion correction can prevent motion artifacts in magnetic resonance imaging of the brain. However, for high-resolution imaging, the technique relies on precise tracking of head motion. This precision is often limited by tracking noise, which leads to residual errors in the prospectively-corrected k-space data and artifacts in the image. This(More)