ISMRM 21st Annual Meeting & Exhibition 20-26 April 2013 Salt Lake City, Utah, USA

Novel Neuroimaging Methods
Wednesday 24 April 2013
Room 150 AG  13:30 - 15:30 Moderators: Christopher D. Kronke, Joshua S. Shimony

13:30 0449.   
3D MRI Microscopy of the Lens, Vitreous, and Anterior Chamber Volumes in Normal Mouse Eyes and Eyes with Retinal Degeneration
Eric R. Muir1 and Timothy O. Duong2
1Research Imaging Institute, University of Texas Health Science Center, San Antonio, TX, United States, 2Research Imaging Institute, UT Health Science Center at San Antonio, San Antonio, TX, United States

Retinitis pigmentosa (RP), which causes photoreceptor death and blindness and affects 1.5 million people worldwide, is characterized by progressive loss of the retina. While the retinal degeneration is well characterized, it is unclear how other structures of the eye in RP are affected. The goal of this study was to develop a 3D MRI approach to image the whole mouse eye in vivo at 47x78x79 µm with high contrast and sensitivity using balanced steady state free precession. We applied this approach to quantify volumes of the lens, vitreous, and anterior chamber in a mouse model of RP.

13:42 0450.   
Anatomical and ASL Imaging of the Retina at 7 T
Daniel James Lee1, Ehsan Vaghefi2, Kevin F. Webb3, Alexander J E Foss4, Richard W. Bowtell1, and Susan T. Francis1
1SPMMRC, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, 2University of Auckland, Auckland, New Zealand, 3University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, 4Queen's Medical Centre, Nottingham, Nottinghamshire, United Kingdom

Using a dedicated receive coil and the high signal-to-noise of a 7 T system, high resolution anatomical images of the human eye have been obtained in vivo. Perfusion images showing retinal blood flow were acquired using a FAIR ASL scheme with a TurboFLASH readout across a range of post-label delay times (TI) , showing largest perfusion signals at the longest TI used here (1550 ms), with average baseline perfusion of 104 ± 41 ml/100 mL/min . Perfusion changes in response to 8 Hz visual stimulation were measured and a 61 % increase in retinal perfusion is detected.

13:54 0451.   
A Fingerprinting Approach to Compute Blood Volume, Vessel Diameter and Blood Oxygenation Maps in the Human Brain
Thomas Christen1, Nicolas Pannetier2,3, Wendy W. Ni1, Deqiang Qiu1, Norbert Schuff2,3, Michael E. Moseley1, and Greg Zaharchuk1
1Radiology, Stanford University, Stanford, California, United States, 2Radiology, University of California San Francisco, San Francisco, California, United States, 3Center for Imaging of Neurodegenerative diseases, Veterans Affairs Medical Centre, San Francisco, California, United States

In this work, we acquired the MR signal time evolution (FID and spin echo) pre and post injection of an intravascular contrast agent in volunteers. We then compared the ratio of the signals to a dictionary of curves obtained using advanced numerical simulations. We show that it is possible with this approach to extract quantitative information about the microvascular network.

14:06 0452.   
Multi-Spectral T1 Weighted Imaging and T1 Quantification Using 3D Radial K-Space Trajectory
Steven Kecskemeti1, Nagesh Adluru1, Samuel A. Hurley2, and Andrew L. Alexander1
1University of Wisconsin, Madison, Wisconsin, United States, 2University of Wisconsin-Madison, Madison, Wisconsin, United States

In this study, 3D radial k-space sampling with inversion recovery is used to image more than 100 points along the magnetization recovery curve in a single exam of duration similar to a standard 3D Cartesian IR-fGRE image. The effective inversion times may be reconstructed as finely as a single TR, enabling the user to retrospectively select the images with the optimal contrast, thereby eliminating the need to select a single, specific inversion time prior to data acquisition. T1 maps are created by fitting the image signals from the different inversion times to a theoretical signal model.

14:18 0453.   MRI Measurements of ICP in Simulated Acute Mountain Sickness (AMS)
Justin Stevan Lawley1, Noam Alperin2, Sang H. Lee2, Paul Gerald Mark Mullins3, Samuel James Oliver1, and Jamie Hugo Macdonald1
1Health and Exercise Sciences, Bangor University, Bangor, Gwynedd, United Kingdom, 2University of Miami, Miami, FL, United States, 3Bangor Imaging Center, Bangor University, Bangor, Gwynedd, United Kingdom

Prolonged exposure to high altitude is often followed by Acute Mountain Sickness, which presents as a number of symptoms including headache, nausea and vomiting. The prevalence of AMS increases with rate of ascent, total altitude gain and irrespective of altitude, a striking individual susceptibility, thought to be the result of a predisposition to intracranial hypertension. Despite the elegance and longevity of this hypothesis, evidence for elevated intracranial pressure (ICP) in concert with AMS is rare due, in part, to the challenging measurement of ICP in healthy individuals. MR estimates of ICP were employed to further elucidate the pathophysiology of AMS.

14:30 0454.   Spatial Distribution of Sevoflurane in the Human Brain Revealed by in-vivo 19F Imaging at Clinical-Relevant Concentrations: Preliminary Results
Maolin Qiu1, Ramachandran Ramani2, and Robert Todd Constable3
1Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, United States, 2Anesthesiology, Yale University School of Medicine, New Haven, CT, United States, 3Diagnostic Radiology, Yale University, New Haven, CT, United States

This study aims to examine the sensitivity of 19F imaging in detecting cerebral Sevoflurane concentrations in humans during 0.5MAC anesthesia and to investigate the spatial distribution during Sevoflurane anesthesia. We have successfully conducted the first 19F imaging study in humans to assess the cortical distribution of the inhalational anesthetic agent – Sevoflurane at clinically-relevant concentrations and demonstrated the possibility of directly mapping the regional Sevoflurane concentration in the brain using 19F imaging with a 1H/19F dual-tuned CP head coil even though the cortical concentration is extremely low. Preliminary results demonstrate the non-uniformity of Sevoflurane distribution in the human brain and provide new insights by directly measuring cortical concentrations during anesthesia.

14:42 0455.   Brain Sodium Accumulation Correlates with Electrical Abnormalities in Drug-Resistant Epilepsy: A 23Na MRI and Intracranial EEG Recording Study
Wafaa Zaaraoui1, Caroline Rey1, Fabrice Bartolomei2,3, Patrick Chauvel2,3, Elisabeth Soulier1, Sylviane Confort-Gouny1, Patrick J. Cozzone4, Lothar R. Schad5, Jean-Philippe Ranjeva1, and Maxime Guye1,6
1CRMBM, UMR 7339, CNRS, Aix-Marseille Université, Marseille, France, 2Pôle de Neurosciences Cliniques, APHM, Marseille, France, 3Laboratoire de Neurophysiologie et Neuropsychologie, U751, INSERM, Aix-Marseille Université, Marseille, France, 4Aix-Marseille Université, Marseille, France, 5Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany, 6Pôle d’Imagerie Médicale, APHM, Marseille, France

Patients suffering from pharmacoresistant partial epilepsy are potential candidates for epilepsy surgery consisting of removal of the epileptogenic zone (EZ). Localization of the EZ during presurgical assessment is a crucial issue and requires invasive intracranial EEG recordings. Therefore, developments of new non-invasive localizing methods are of particular interest. We demonstrated for the first time that abnormal accumulation of sodium concentrations succeeded to lateralize epilepsy and that sodium concentrations in the grey matter of patients are correlated with the interictal electrical abnormalities in regions of the epileptogenic zone. Brain sodium MRI appears as a promising non-invasive presurgical tool in drug-resistant epilepsy.

14:54 0456.   Quiet T1-Weighted Head Scanning Using PETRA
David Manuel Grodzki1 and Bjoern Heismann1,2
1Siemens AG, Erlangen, Germany, 2Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany

Silent T1-weighted head scanning using the PETRA sequence is investigated in this work. Inversion pulses are used to enhance the T1 contrast. Optimization of the settings for the inversion and waiting times are performed by simulation and volunteer scans. The in-vivo results show that the PETRA sequence generates image quality, SNR and CNR between grey and white brain matter comparable to the MPRAGE sequence. Without the need of hardware changes, PETRA might be a silent substitute for the MPRAGE sequence in many applications.

15:06 0457.   
7T MRSI in Temporal Lobe Epilepsy -permission withheld
David Bonekamp1, He Zhu1, Gregory Bergey2, and Peter B. Barker1
1The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, Maryland, United States, 2Department of Neurology, Johns Hopkins University, Baltimore, Maryland, United States

In this study, control subjects and a cohort of epilepsy patients with a clinical diagnosis of unilateral epilepsy underwent MRSI at 7T. Similar to prior studies at lower fields, 7T MRSI of the hippocampi showed bilateral mid-hippocampal tNAA decreases, accentuated at the side of clinical and MRI abnormality. Lateralization of the clinical focus was not possible, due to significant contralateral tNAA decrease. Future comparative studies are needed to compare the relative value of 7T vs. 3T MRSI, as well as the relative value of 7T MRSI to other MRI sequences, in patients with temporal lobe epilepsy.

15:18 0458.   Imaging of Focal Cortical Dysplasia at 7 Tesla
Mathijs Buijs1, Albert Colon1,2, Matthias van Osch1, Jeroen van der Grond1, Paul A. Boon2,3, Paul A.M. Hofman2,4, and Mark A. van Buchem1
1Leiden University Medical Center, Leiden, Zuid-Holland, Netherlands, 2Epilepsy Centre Kempenhaeghe, Heeze, Noord-Brabant, Netherlands, 3Ghent University Hospital, Ghent, Oost-Vlaanderen, Belgium, 4Maastricht University Medical Center, Maastricht, Limburg, Netherlands

Focal cortical dysplasia (FCD) is thought to be a major cause of cryptogenic localization-related epilepsy, in which conventional MRI is unable to detect a lesion. Scanning at higher field strenghts is likely to increase sensitivity to small lesions, improving the chances of a better surgical outcome. In this pilot study we scanned 10 patients who were diagnosed at 3 Tesla with FCD type II with a 7 Tesla MRI scanner. Features of FCD at 7T were described and compared to the findings at 3T.