TRADITIONAL POSTER - ismrm

Poster Sessions
1816. Brain Tissue Flow Measurement Using Arterial Spin Labeling with Flow Discrimination by
Cumulative Readout Pulses
Yi Wang 1 , Allison Payne 2 , Seong-Eun Kim 2 , Edward DiBella 2 , Dennis L. Parker 2
1 Bioengineering, University of Utah, Salt Lake City, UT, United States; 2 Utah Center for Advanced Imaging Research, University of
Utah, Salt Lake City, UT, United States
The Pennes' perfusion term in the Pennes bioheat transfer equation depicts the rate at which blood flow removes heat from a point and can play an important
role in tissue heat dissipation. Because tissue perfusion is known to change over the course of a thermal therapy treatment, the ability to perform multiple
flow assessments to detect perfusion changes during magnetic resonance-guided high-intensity focused ultrasound treatment is of high importance. In this
work, we present a method to use arterial spin labeling to determine the Pennes' perfusion term in brain tissue and evaluate performance as a function of
various imaging parameters, such as flip angle , bandwidth, and resolution. The results indicate that the proposed technique could be applied in MRgHIFU
to provide an efficient estimate of the Pennes' perfusion term. Although demonstrated on brain tissue, this technique could be applied to other tissue types.
Thermotherapy
Hall B Wednesday 13:30-15:30
1817. Dual-Echo Sequence for MR Thermometry in Moving Objects
Bruno Madore 1 , Lawrence P. Panych 1 , Chang-Sheng Mei 1,2 , Renxin Chu 1
1 Radiology Department, Brigham and Women's Hospital, Harvard Medical School , Boston, MA, United States; 2 Department of
Physics, Boston College, Chestnut Hill, MA, United States
An MR thermometry dual-echo sequence is proposed here that offers advantages both in terms of temperature-to-noise ratio and image contrast, as compared
to typically-used sequences. For thermometry in moving organs, the contrast properties of the proposed sequence allow blood vessels to be readily detected,
for motion tracking purposes.
1818. Fat Temperature Imaging with T1 of Fatty Acid Species Using Multiple Flip Angle Multipoint Dixon
Acquisitions
Kagayaki Kuroda 1,2 , Taku Iwabuchi, Mie Kee Lam 3 , Makoto Obara 4 , Masatoshi Honda 5 , Kensuke Saito,
Marc Van Cauteren 4 , Yutaka Imai 5
1 Graduate School of Engineering, Tokai University, Hiratsuka, Kanagawa, Japan; 2 Medical Device Development Center, Foundation
for Biomedical Research and Innovation, Kobe, Hyogo, Japan; 3 Image Sciences Institute, University Medical Center Utrecht, Utrecht,
Netherlands; 4 MR Marketing, Philips Electronics Japan Medical Systems, Shinagawa, Tokyo, Japan; 5 Department of Radiology, Tokai
University, Isehara, Kanagawa, Japan
A fat temperature imaging technique based on multiple flip angle, multipoint Dixon acquisitions and a least square estimation scheme is proposed. Gradient
recalled acquisition of 5 echo times with 3 different flip angles were obtained to separate the signals of methylene and methyl protons and to estimate T1's of
these fatty acid species. Temperature images of a water-oil phantom were successfully obtained with previously obtained temperature coefficients
demonstrating the feasibility of quantitative thermometry of fat. Since the acquisition time was 4-6 second, the technique seemed to be practical for
temperature monitoring of fat-water tissues like breast under thermal therapies.
1819. Novel Body Coil Driven Radio Frequency Ablation Device
Yik-Kiong Hue 1 , Jerome L. Ackerman 1 , Erez Nevo 2
1 Martinos Center, Department of Radiology, Massachusetts General Hospital, Boston, MA, United States; 2 Robin Medical, Inc.,
Baltimore, MD, United States
A novel body coil driven radiofrequency ablation (RFA) device is proposed. It provides an alternative to commercial available RFA device which required
external power generator and large grounding pad. It allowed MR scanner as the sole modality to localize tumor, probe placement, RF power control,
temperature mapping and tissue monitoring.
1820. Temperature and B0 Field Measurment Bias of Multi-Echo Fat-Water Fitting Algorithms
Cory Robert Wyatt 1 , Brian J. Soher 2 , James R. MacFall 2
1 Department of Biomedical Engineering, Duke University, Durham, NC, United States; 2 Department of Radiology, Duke University
Medical Center, Durham, NC, United States
Multi-echo fat-water separation techniques, such as IDEAL, have been shown to be effective in measuring temperature changes in fatty tissue, but often
make assumptions that allow them to linearize the model in order to simplify the computation of a solution. This can result in the addition of significant bias
to the measurement of the temperature and the B0 field offset, both important parameters to monitor during therapeutic heat applications (tumor ablation,
hyperthermia). In this work, the bias of a multi-peak IDEAL algorithm (without T2* decay) and a new nonlinear fitting algorithm is characterized using
Monte Carlo simulations.