TRADITIONAL POSTER - ismrm

Poster Sessions
1075. A Low-Cost Experimental Set-Up for Functional Magnetic Resonance Imaging
Carolina Arboleda 1,2 , Cristián Andrés Tejos 1,2 , Sergio Uribe, 2,3 , Francisco Zamorano 4 , Francisco Aboitiz 4 ,
Pablo Irarrazaval 1,2
1 Electrical Engineering Department, Pontificia Universidad Católica de Chile, Santiago, Chile; 2 Biomedical Imaging Center, Pontificia
Universidad Católica de Chile, Santiago, Chile; 3 Radiology Department, Pontificia Universidad Católica de Chile, Santiago, Chile;
4 Cognitive Neuroscience Laboratory, Pontificia Universidad Católica de Chile, Santiago, Chile
An fMRI setup for stimuli presentation, should include a coupling circuit to connect the MR-scanner output pulse to the computer that presents the stimuli
(scanner trigger detector, STD), and a Response-Detection Pad (RDP) which needs to be placed inside the scanner and, thus, can not contain any
ferromagnetic materials. Currently, there are several RDC and STD commercially available, but their cost is significantly high (~3,000 USD + shipment).
Here, we propose a cheap (~155 USD + shipment) setup that includes a fiber optic RDP and a photo coupler-based STD, and is compatible with current
scanners and fMRI software.
1076. NSF Risk Factors
Honglei Zhang 1 , Giles H. Roditi 2 , Tim Leiner 3 , Walter Kucharczyk 4 , Martin R. Prince 1
1 Radiology, Weill Medical College of Cornell University, New York, NY, United States; 2 Radiology, Glasgow Royal Infirmary,
Scotland; 3 Maastricht University Hospital, Netherlands; 4 University of Toronto, Toronto, Ontario, Canada
Concern about the association between GBCA and NSF has led to widespread screening of MRI patients for renal dysfunction and withholding GBCA when
GFR is < 30 mL/min. Analysis of 78 retrospective case series reporting 292 NSF cases explores the risk factors for NSF. Elimination of multiple risk
factors by using single dose GBCA, dialyzing dialysis patients quickly following GBCA administration, avoiding GBCA in acute renal failure while serum
creatinine is rising, and avoiding non-ionic linear GBCA in renal failure patients, may reduce NSF risk more than a thousand fold, thereby allowing safe
GBCA enhanced MRI in virtually all patients.
fMRI Acquisition
Hall B Monday 14:00-16:00
1077. Separating FID and Echo Contribution in Pass-Band BSSFP FMRI with Multiple-Phase Angle Cycling
Sung-Hong Park 1,2 , Tae Kim 1 , Ping Wang 1 , Timothy Q. Duong 2 , Seong-Gi Kim 1
1 Radiology, University of Pittsburgh, Pittsburgh, PA, United States; 2 Research Imaging Institute, Ophthalmology/Radiology,
University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
We acquired high resolution multiple phase-cycled bSSFP fMRI datasets in rat brains at 9.4T and separated FID and main echo components based on
Fourier analysis. The FID component showed stronger fMRI signals than the main echo component, but it showed stronger correlation with both
intracortical veins and cortical surface veins. The fMRI signal from the main echo component could contribute up to half of that from the FID component,
implying that the main echo component should not be neglected in interpreting pass-band bSSFP fMRI signals.
1078. A Novel Multi-Echo FMRI Weighting Strategy Using Principal Component Analysis for BOLD
Contrast Sensitivity Enhancement
Mark Chiew 1,2 , Simon James Graham 1,2
1 Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; 2 Rotman Research Institute, Toronto, Ontario, Canada
The use of multi-echo imaging techniques for contrast enhancement in BOLD fMRI is gaining momentum, particularly in real-time fMRI applications. A
novel method is presented for combining multi-echo signals in weighted summation using principal component analysis (PCA) derived weights. The method
is evaluated on human volunteers performing a simple motor task at 1.5 T, and is compared to other reported weighting schemes. The data driven PCA
weighting method is demonstrated to produce time-series that achieve high relative contrast-to-noise ratio gain, without requiring additional data collection.
1079. Variable Density Spiral FMRI
Catie Chang 1 , Gary Harold Glover 1
1 Electrical Engineering & Radiology, Stanford University, Stanford, CA, United States
We propose a novel variable-density (VD) spiral k-space trajectory for brain fMRI. The trajectory consists of an Archimedean spiral from the origin out to
an arbitrary radius k1, extending beyond k1 with a spiral in which the sampling density decreases as the k-space radius increases. Thus, it allows for a
reduction in readout time at the expense of undersampling only high spatial frequencies. We implemented the VD spiral in a single-shot 2D spiral-in/out
sequence for high (128x128) resolution, and demonstrate improved activation in a sensory-motor task compared to conventional (fully Archimedean) singleshot
and interleaved sequences.
1080. High Resolution BOLD FMRI Using MHASTE
Yongquan Ye 1 , Yan Zhuo 1 , Xiaohong Joe Zhou 2
1 State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics,CAS, Beijing, China; 2 University of Illinois Medical
Center, Chicago, IL, United States
High resolution BOLD fMRI data on visual cortex were acquired using mHASTE, a novel GRAPPA accelerated single shot TSE technique, and the results
were compared with those of GE- and SE-EPI. Higher SNR was obtained with mHASTE than both EPIs, and increased functional activation was detected by
mHASTE but not by EPI when going from low resolution to high resolution. mHASTE was also found to have greater activation than both EPI in some
cases,especially at high resolution, suggesting a more robust BOLD contrast mechanism for mHASTE in high resolution fMRI.