Learn More
A nuclear magnetic resonance imaging (MRI) method is presented for quantitatively mapping the physical response of a material to harmonic mechanical excitation. The resulting images allow calculation of regional mechanical properties. Measurements of shear modulus obtained with the MRI technique in gel materials correlate with independent measurements of(More)
Respiratory motion is a major limiting factor in improving image resolution and signal-to-noise ratio in MR coronary imaging. In this work the effects of respiration on the cardiac position were studied quantitively by imaging the heart during diastole at various positions of tidal respiration with a breath-hold segmented fast gradient echo technique. It(More)
An important part of thermal ablation therapy is the assessment of the spatial extent of tissue coagulation. In this work, the mechanical properties of thermally-ablated tissue were quantitatively evaluated using magnetic resonance elastography (MRE). This study shows that the mechanical properties of focused ultrasound ablated tissue are significantly(More)
An adaptive technique for measuring and correcting the effects of patient motion during magnetic resonance image acquisition was developed and tested. A set of algorithms that can reverse the effects of object displacements and phase shifts was used. These algorithms essentially transfer the frame of reference of the image reconstruction from the static(More)
The purpose of this study was to obtain normative data using magnetic resonance elastography (MRE) (a) to obtain estimates of the shear modulus of human cerebral tissue in vivo and (b) to assess a possible age dependence of the shear modulus of cerebral tissue in healthy adult volunteers. MR elastography studies were performed on tissue-simulating gelatin(More)
PURPOSE To describe a clinically useful application of functional magnetic resonance (MR) imaging--presurgical mapping of the sensory motor cortex--and to validate the results with established physiologic techniques. MATERIALS AND METHODS Functional MR mapping of the sensory motor cortex was performed in two women, aged 24 and 38 years. Both had(More)
Often compared to the practice of manual palpation, magnetic resonance elastography is an emerging technology for quantitatively assessing the mechanical properties of tissue as a basis for characterizing disease. The potential of MRE as a diagnostic tool is rooted in the fact that normal and diseased tissues often differ significantly in terms of their(More)
Corruption of the image time series due to interimage head motion limits the clinical utility of functional MRI. This paper presents a method for real-time prospective correction of rotation and translation in all six degrees of rigid body motion. By incorporating an orbital navigator (ONAV) echo for each of the sagittal, axial, and coronal planes into the(More)
Noninvasive quantitation of the mechanical properties of tissue could improve early detection of pathology. Previously a method for detecting displacement from propagating shear waves using a phase-contrast MRI technique was developed. In this work it is demonstrated how a collection of data representing the full vector displacement field could be used to(More)
Despite the fact that respiratory motion is a major factor limiting the image quality of MR examinations in the upper abdomen, little quantitative information is available about the kinematics of visceral motion during respiration. The objective of this study was to obtain a measure of the relative longitudinal and transverse displacements of the upper(More)