Electronic poster

Wednesday 13:30-15:30 Computer 89

13:30 4526. Effects of Lactoferrin on Altered Brain Metabolism in Pup Rats After Prenatal Exposure to Dexamethasone

Yohan van de Looij^1,2, Pierre Larvaron¹, Emmanuel Somm¹, Bing Wang³, Rolf Gruetter^2,4, Stéphane V. Sizonenko¹, Petra S. Hüppi<sup>1

1</sup>Division of Child Growth & Development, Department of Pediatrics, University of Geneva, Geneva, Switzerland; ²Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; ³Department of Nutrition and Health, Nestlé Research Center, Lausanne, Switzerland; ⁴Department of Radiology, University of Geneva and Lausanne, Geneva and Lausanne, Switzerland

Rat model of glucocorticoids exposure during gestation has shown reduction in brain weight. At P7, alterations of cerebral metabolism in the cortex and the hippocampus have been observed by in vivo 1H-MRS. Lactoferrin (Lf) is an iron-binding glycoprotein secreted in milk which has an antioxidant activity. The aim of this work was to evaluate the neuroprotective effect of Lf following prenatal exposure to glucocorticoids by high field localized 1H-MRS. Neurochemical profiles of the pup rat brains confirmed the altered brain development after Dex exposure and revealed the potential protective effect of Lf given to gestational and lactating dams.

14:00 4527. Proton MRS in the Late Stage of Neonatal Hypoxic-Ischemic Cerebral Injury

April M. Chow^1,2, Iris Y. Zhou^1,2, Shu Juan Fan^1,2, Kannie W.Y. Chan^1,2, Kevin C. Chan^1,2, Ed X. Wu<sup>1,2

1</sup>Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China

Neonatal hypoxic-ischemic (HI) cerebral injury is major cause of permanent damage to neuronal cells. The neonatal brain undergoes regenerative processes late after HI injury. While ¹H MRS has been employed to investigate metabolic changes during acute-phase of HI injury, roles of major neurochemicals as markers for neurodegeneration and neuroprotection at late stage are also important for studying the neurophysiological changes. In this study, we showed that alteration in the metabolism at late stage in cortical and subcortical structures is associated with neonatal HI cerebral injury. This may provide insights into the plastic changes and adaptive modifications within brain following injury.

14:30 4528. Localized in Vivo ¹H NMR Spectroscopy of the Rat Brain at 16.4T

Sung-Tak Hong¹, Dávid Zsolt Balla¹, Gunamony Shajan¹, Changho Choi², Kamil Ugurbil³, Rolf Pohmann<sup>1

1</sup>High-Field Magnetic Resonance Center , Max-Planck Institute for Biological Cybernetics, Tuebingen, Baden-Wuerttemberg, Germany; ²Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States; ³Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States

In vivo 1H NMR spectroscopy has several problems including narrow spectral dispersion and low SNR. Increasing a static field strength could alleviate these problems, providing feasibilities of quantifying metabolites not observable at lower field strength. The acquisition of an enhanced neurochemical profile was obtained by minimizing TE up to 1.7 ms in a STEAM sequence at 16.4T. The technique demonstrated possibilities of quantification of additional metabolites, acetate and ethanolamine, in the rat brain in vivo.

15:00 4529. A Multinuclear NMR Study of Glucose Metabolismin Thiamine-Deficient Cerebellar Granule Cells: New Mechanistic Insights

Abolghasem Mohammadi¹, Claudia Zwingmann<sup>1

1</sup>Département de médicine, Université de Montréal, Montreal, Quebec, Canada

Wernicke's encephalopathy is a neurological disorder which is characterized by disturbances in consciousness and region-selective brain lesions. Brain damage is associated with a deficiency in thiamine, an essential vitamine in carbohydrate metabolism. Multinuclear NMR spectroscopy was used to assess carbon fluxes and cellular energy state of thiamine-deficient cultured rat cerebellar granule neurons. The data show that neuronal energy failure and death likely result from a primary impairment of neuronal a-KGDH causing impaired carbon flux from glucose/pyruvate through PDH, decreased catabolism of glutamine, and lactate accumulation. Under hyperglycemic conditions, however, alternative explanations to the lactic acidosis hypothesis have to be considered.

Thursday 13:30-15:30 Computer 89

13:30 4530. Taurine Change in Visual Cortex of Neonatal Monocular Enucleated Rat: A Proton MRS Study

April M. Chow^1,2, Iris Y. Zhou^1,2, Shu Juan Fan^1,2, Kannie W.Y. Chan^1,2, Kevin C. Chan^1,2, Ed X. Wu<sup>1,2

1</sup>Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China

Neonatal monocular enucleation has been used to study developmental mechanisms underlying visual perception and the cross-modal changes in the central nervous system caused by early loss of the visual input. In this study, we demonstrated that alteration in the metabolism of taurine in visual cortex accompanied with neonatal monocular enucleation could be monitored using ¹H MRS at 7 T. The change in taurine signal with respect to creatine signal may possibly due to the increased taurine signal in the right control visual cortex, likely caused by the plasticity resulted from recruitment of resources to the remaining left eye for adaptation.

14:00 4531. Simultaneously Measuring Glucose Transport Constants and Cerebral Metabolic Rate of Glucose by in Vivo ¹H MRS in the Rat Brain

Fei Du^1,2, Yi Zhang¹, Xiao-Hong Zhu¹, Wei Chen<sup>1

1</sup>Radiology, Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, United States; ²Psychiatry, McLean Hospital, Harvard University, Belmont, MA, United States

The basal brain activity and function depends upon a constant supply of glucose through the specific glucose transport mechanism mediated by transporter molecules, referred to as the blood-brain barierr (BBB). Therein the noninvasive method to reliably measure glucose cerebral metabolic rate and transport constants are of importance for understanding underlying glucose transport mechanism and energy consumption in the various physiological or pathological conditions. For instance, in our previous studies, we observed that compared to the light anesthesia (2% v-v isofulorane), brain glucose concentration significantly decreased although cerebral metabolic rate of glucose (CMRglc) decreased 37% at the iso-electric condition. This observation of glucose reduction seemingly contradicted with other studies showing a decreased brain glucose concentration accompanied by the increased CMR_glc due to the elevated stimulations. This apparent discrepancy can be explained by the changes of blood plasma glucose concentrations, which were found to be substantially decreased under the iso-electric conditions. Another possible reason is alterations of glucose transport constants (K_T and T_max). It was reported that pentobarbital reduced blood-brain glucose transfer in the rat brain and the glucose transport constants decreased compared to the awaken condition. Therefore, the aim of the current study is to build-up a noninvasive method to reliably and simultaneously measure CMR_glc and transport constants for fully understanding brain glucose concentration changes with alterations of anesthesia depth. The method was introduced and implemented by simultaneously measuring plasma and brain tissue glucose concentration time courses after stopping glucose infusion.

14:30 4532. 1H MRS of Cortical and Subcortical Structures in Mild and Severe Neonatal Hypoxic-Ischemic Cerebral Injuries

Kevin C. Chan^1,2, Ed X. Wu<sup>1,2

1</sup>Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China; ²Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

This study employed in vivo 1H MRS to understand the metabolic alterations in cortical and subcortical structures during the recovery period upon mild and severe hypoxic-ischemic (HI) injuries to the neonatal rat brains. Relative to the Cr peak, results showed a further increase in Cho, Glu and Lac in the left cortex of severe HI group than mild HI group at 3 days after HI injury at postnatal day 7. These values then decreased slightly at 7 days after surgery in both HI groups. Tau also increased on both sides of the cortex at Day 3 and then drop at Day 7 for both HI groups. In the left thalamus of the severe HI group, NAA appeared to decrease transiently at Day 3 and normalize at Day 7, whereas Cho, Glu, Lac and Tau levels apparently peaked at Day 3. The results of this study may help to investigate potential therapies and the recovery mechanisms upon different severity of neonatal HI insults.

15:00 4533. Early Metabolic Changes Following Focal Traumatic Brain Injury in Rats Measured Using ¹H MRS

Su Xu^1,2, Steve Roys, ²³, Jennifer Racz⁴, Da Shi^1,2, Jiachen Zhuo^1,2, Rao Gullapalli, ²³, Gary Fiskum<sup>1,4

1</sup>Core for Translational Research in Imaging @ Maryland (C-TRIM), University of Maryland School of Medicine, Baltimore, MD, United States; ²Diagnostic Radiology and Nuclear Medicine, University of Maryland School of Medicine, Baltimore, MD, United States; ³Core for Translational Research in Imaging @ Maryland (C-TRIM), University of Maryland School of Medicine, Baltimore, MD, United States; ⁴Anesthesiology and the Center for Shock Trauma and Anesthesiology Research, University of Maryland School of Medicine, Baltimore, MD, United States

Traumatic brain injury is characterized by acute physiological changes that may play a significant role in the final outcome resulting from the injury. Experimental models of TBI provide a useful tool for understanding the early cerebral metabolic changes induced by the damage. In this study, we investigate the early post-traumatic changes in neuro-metabolites in the rat brain following controlled cortical impact injury using in vivo ¹H MRS at 7 Tesla. Significant changes in N-acetylaspartate, glutamate and choline were observed within the first 3 hours after injury in the pericontusional area suggesting a possible temporal window for therapeutic intervention.

Breast MR: Diffusion, Spectra & High Field

Hall B Monday 14:00-16:00 Computer 90

14:00 4534. Diffusion MR Breast Imaging: Correlation of ADC Values to the Prognostic Factors

Sunitha B. Thakur¹, David D. Dershaw², Dilip Giri³, Junting Zheng⁴, Chaya Moskowitz, Jessica Ferrara², Jason A. Koutcher¹, Elizabeth A. Morris<sup>2

1</sup>Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States; ²Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States; ³Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, United States; ⁴Epidemiology-Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, United States

Treatment decisions and determination of breast cancer prognosis have traditionally been based on pathologic parameters such as tumorsize and axillary-nodal status, tumor-grade, and the results of tumor markers mainly ER/PR and HER-2/neu. Here we present the clinical usefulness of Diffusion-weighted MRI and measurement of apparent diffusion coefficients (ADCs) to correlate traditional markers such as histology and molecular markers such as ER, PR and HER-2. Mean tumor size is significantly higher in patients with positive lymph nodes. Although ADC values represent a valuable biomarker for detecting malignant lesions, the ADC cannot be a prognostic indicator for patients with breast cancer.

14:30 4535. Post Lumpectomy MRI: Using Diffusion Weighted Imaging (DWI) to Distinguish Benign from Malignant Tissues

Frederick Kelcz¹, Kendra S. Hain<sup>1

1</sup>Radiology, University of Wisconsin, Madison, WI, United States

We reviewed diffusion imaging results in post lumpectomy patients and preliminary results show a consisent ADC value in the benign range, despite persistent, occasionly concerning enhancement. DWI may be of great value in ruling in benignancy when differentiating enhancing scar from malignancy.

15:00 4536. Diffusion MR Breast Imaging: ADC Values for Differentiating of Malignant from Benign Breast Tumors

Sunitha B. Thakur^1,2, David D. Dershaw², Dilip Giri³, Junting Zheng⁴, Chaya Moskowitz, Jason A. Koutcher^1,2, Elizabeth A. Morris<sup>2

1</sup>Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY, United States; ²Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States; ³Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, United States; ⁴Epidemiology-Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY, United States

Diffusion MRI is a noninvasive technique which provides information about early changes in morphology and physiology of tissues by monitoring changes in the local apparent diffusion coefficient (ADC) of water molecules. Recently, diffusion-imaging has demonstrated potential in discriminating malignant from benign breast tumors and in assessing progression of disease following therapy. In this work we present the clinical usefulness of DWI and ADC values. ADC measurements are useful to differentiate malignant lesions from benign lesions yielding 98.4 % specificity and 90.9 % sensitivity with ADC cut-off value of 1.28x10^-3 mm²/s. ADC was less reliable for differentiating invasive and non-invasive carcinomas.

15:30 4537. Diffusion Weighted Imaging of the Breast: Can It Decrease the Number of Unneeded Biopsies?

Wafaa Raafat Abdel Hamid¹, Lobna Rashed Ezz El Arab, Mona Ahmed Mohamed², Yasser Abdel Azim Abbas

¹Radiodiagnosis, Ain Shams University, Cairo, Egypt; ²Johns Hopkins University school of medicine

Classic magnetic resonance imaging is based on the enhancement pattern of lesions in dynamic breast MRI and morphologic changes. However, there is an overlap of these criteria with benign lesions. Accordingly, problematic cases have always been subjected to biopsies and histopathological verification. In our work we are shedding light on the added value of Diffusion Weighted Imaging and ADC values in differentiating between benign and malignant breast lesions, with a major goal of sparing patients the invasiveness and complications of unneeded biopsies.

Tuesday 13:30-15:30 Computer 90

13:30 4538. Motion and Distortion Correction in Diffusion-Weighted MRI of the Breast at 3T

Lori R. Arlinghaus^1,2, E. Brian Welch^1,3, A. Bapsi Chakravarthy⁴, Jaime S. Farley⁵, John C. Gore^1,2, Thomas E. Yankeelov<sup>1,2

1</sup>Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States; ²Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, United States; ³MR Clinical Science, Philips Healthcare, Cleveland, OH, United States; ⁴Radiation Oncology, Vanderbilt University, Nashville, TN, United States; ⁵Vanderbilt University Medical Center, Vanderbilt University, Nashville, TN, United States

Diffusion-weighted imaging (DWI) is a promising surrogate biomarker for the characterization of human breast cancer. However, DWI acquisition sequences are susceptible to artifacts induced by subject motion and eddy currents. DWIs acquired with echo planar imaging (EPI) techniques are also prone to nonlinear distortion induced by B₀ field inhomogeneities, which worsen as field strength increases. We present evidence that image registration and B₀ field map correction improve the quality of apparent diffusion coefficient (ADC) maps derived from the DWI data and improve the registration of the DWI data with anatomical images for comparison with other parametric maps.

14:00 4539. Operator Performance of Voxel Placement for Single-Voxel MRS of Breast Lesions

Naomi R. Mraz¹, Michael T. Nelson¹, Jessica Kuehn-Hajder¹, Greg John Metzger², Patrick John Bolan<sup>2

1</sup>Radiology, University of Minnesota, Minneapolis, MN, United States; ²Radiology/CMRR, University of Minnesota, Minneapolis, MN, United States

In order for single-voxel MRS measurements to be a useful clinical tool for characterizing breast lesions, voxel placement must be accurate and consistent. This project tested the consistency of voxel placement between four different operators using a retrospective study to simulate voxel placement on a MR scanner. The relative geometric intersection was used as a measure of concordance between readers. Overall concordance was lower than expected (ranging 0%-82.5%, mean 31.2%). Concordance was higher for masses than for non-mass-like lesions. These results suggest that further training, guidance, or software support should be used to improve voxel placement consistency.

14:30 4540. 1H MR Spectroscopy of the Breast Cancer at 3.0-Tesla: Comparison Between Pre- And Post- Contrast Administration.

Hisashi Kawai¹, Shinji Naganawa¹, Hiroko Satake¹, Satoko Ishigaki<sup>1

1</sup>Radiology, Nagoya University, Nagoya, Japan

The purpose of this study was to assess whether VOIs of MRS were located properly with non-contrast MRI and to compare the variability between pre- and post-contrast spectroscopic measurements at 3T-MRI.

Single-voxel MRS were performed in 92 breast cancer lesions. In 52 lesions, MRS was obtained before and after contrast-enhanced MRI. VOI were located in the lesion properly in 74 out of 92 breast cancers. The integral value of choline peak decreased significantly in post-contrast MRS compared to in pre-contrast MRS. MRS should be obtained before contrast administration not to be affected by Gadolinium contrast agents.

15:00 4541. The Impact of Gd-DTPA on Breast ¹H MRS

Patrick John Bolan¹, Eva H. Baker², Lance Jay DelaBarre¹, Hellmut Merkle³, Doug Yee⁴, Michael T. Nelson⁵, Lenore Everson⁵, Michael Garwood<sup>1

1</sup>Radiology/CMRR, University of Minnesota, Minneapolis, MN, United States; ²Diagnostic Radiology Department, NIH Clinical Center, Bethesda, MD, United States; ³National Institute Neurological Disorders and Stroke, NIH, Bethesda, MD, United States; ⁴Masonic Cancer Center, University of Minnesota, Minneapolis, MN, United States; ⁵Radiology, University of Minnesota, Minneapolis, MN, United States

While ¹H MRS is increasingly being used in clinical studies of breast cancer, there has been some evidence that the use of Gadolinium-based contrast agents prior to MRS can affect the spectra, broadening the choline resonance and reducing its area. This work describes a study performing ¹H MRS at 4T before and after a bolus of Gd-DTPA. It was found that after the contrast injection there was a small negative impact on both the choline and water peaks, with an effect size of 10-15%.

Wednesday 13:30-15:30 Computer 90

13:30 4542. Measurement of the Breast Density Using IDEAL-Dixon Imaging at 3T

Sungheon Kim¹, Tess Clendenen², Sherlin Lavianlivi¹, Linda Moy¹, Henry Rusinek¹, Malcolm C. Pike³, Anne Zeleniuch-Jacquotte<sup>4

1</sup>Center for Biomedical Imaging, Radiology, NYU School of Medicine, New York, NY, United States; ²Epidemiology, NYU School of Medicine, New York, NY, United States; ³Preventive Medicine, USC Keck School of Medicine, Los Angeles, CA, United States; ⁴Environmental Medicine, NYU School of Medicine, New York, NY, United States

This study was to assess if Dixon water/fat images could be used to monitor breast volume and density changes during the menstrual cycle. Reproducibility of the volume and density measurement was assessed with data from four subjects. In addition, five healthy premenopausal women were scanned once a week for four weeks. The median breast volume was smallest in the ovulatory phase and largest in the late luteal phase. FG density was lowest at the follicular phase and highest in the late luteal phase. This result demonstrates the feasibility of using Dixon imaging to monitor the change in the breast.

14:00 4543. Quantitative Evaluation of Fat Suppression Techniques for Breast MRI at 3.0T

Chen Lin¹, Laurie Owens¹, Hal Kipfer¹, Helmuth Schultze-Haakh², Brian Dale<sup>2

1</sup>Department of Radiology and Imaging Science, Indiana University School of Medicine, Indianapolis, IN, United States; ²Siemens Healthcare, Marlven, PA

Quantitative assessment of the quality of fat suppression in breast MRI with four different techniques, conventional quick fat (QFS), spectrally selective adiabatic inversion recovery (SPAIR), water only excitation (WE) and two point dixon (2PT DIXON) was made at 3.0T. The result demonstrates similar but inferior performance for QFS, SPAIR and WE. While 2PT DIXON is shown to provide superior fat suppression, further development is needed.

14:30 4544. Determining the Sensitivity and Specificity of High Spatial Resolution 3.0T Breast MRI in a High Risk Familial Breast Cancer Screening Cohort

Martin D. Pickles¹, Lindsay W. Turnbull<sup>1

1</sup>Centre for MR Investigations, University of Hull, Hull, East Yorkshire, United Kingdom

Theoretically breast MR examinations at 3.0T should be superior to 1.5T studies. However, breast imaging on higher field strength systems also pose problems such as larger chemical shift, susceptibility artefacts, B1 inhomogeneities and increased T1 relaxation times. The aim of this work was to compare the sensitivity and specificity achieved by a 3.0T MR breast screening programme against the published results of screening studies at 1.5T. In conclusion the diagnostic accuracy of MR breast screening at 3.0T does not seem to be adversely effected by high field strength related artefacts and the results are comparable to those published at 1.5T.

15:00 4545. Assessing the Accuracy of a Commercial Computer Aided Diagnosis Package (CADstream) in Determining the Level of Disease Post Neoadjuvant Chemotherapy in a Cohort of Breast Cancer Patients

Martin D. Pickles¹, Lindsay W. Turnbull<sup>1

1</sup>Centre for MR Investigations, University of Hull, Hull, East Yorkshire, United Kingdom

CADstream is a computer aided diagnosis package developed to aid in the interpretation of breast MR. Reports have demonstrated that CADstream provides quicker interpretation, increased specificity and greater correlation with histological size. However, these reports are based on the assessment of pre-treatment lesions and not post chemotherapy lesions where a treatment induced vascular shutdown is anticipated. The aim of this study was to assess CADstream’s accuracy post chemotherapy. In conclusion this study demonstrated by reducing the enhancement and difference thresholds the sensitivity can be increased resulting in fewer false negative results.