Beatrice Sacconi¹, Roy Raad², Joon Lee³, Howard Fine⁴, John Golfinos⁵, Girish Manokar Fatterpekar⁶, Fernando Boada⁷, Kent Friedman³, James Babb³, and Rajan Jain^3
1Radiological, Oncological and Anatomopathological Sciences, Sapienza University of Rome, Policlinico Umberto I, Rome, Rome, Italy, ²Radiology, NYU School of medicine, New York, New York, United States, ³Radiology, NYU School of Medicine, New York, New York, United States, ⁴Neuro-oncology, NYU Langone Medical Center, New York, New York, United States, ⁵Neurosurgery, NYU Langone Medical Center, New York, New York, United States, ⁶Radiology, NYU Langone Medical Center, New York, New York, United States, ⁷Neurosurgery, Psichiatry and Radiology, NYU Langone Medical Center, New York, New York, United States

Combined functional (MR perfusion) and metabolic (FDG-PET) assessment of brain tumors using hybrid MR-PET provides good accuracy and complimentary information about brain tumors which could be useful as a diagnostic and surveillance tool. PWI and tumor blood volume estimation performs better as compared to FDG uptake assessment in differentiating low versus high-grade tumors as well as in differentiating recurrent tumor from treatment/radiation induced necrosis in previously treated patients in a concurrent hybrid setting.

Christine Preibisch^1,2, Mathias Lukas³, Anne Kluge¹, Severin Keinath³, Vivien Tóth^1,4, Kuangyu Shi³, Thomas Pyka³, and Stefan Förster^3
1Department of Neuroradiology, Klinikum rechts der Isar der TU München, Munich, Germany, ²Clinic for Neurology, Klinikum rechts der Isar der TU München, Munich, Germany, ³Department of Nuclear Medicine, Klinikum rechts der Isar der TU München, Munich, Germany, ⁴Department of Radiology, Klinikum rechts der Isar der TU München, Munich, Germany

Preliminary multimodal MR/PET data from 18 patients with glioblastoma are presented with the aim of a comprehensive characterization of tumor pathophysiology. A semi-quantitative BOLD-based parameter, related to vascular de-oxygenation, termed relative oxygen extraction fraction (rOEF), was acquired simultaneously with 18F-FET PET, which has been shown to be valuable for detecting highly malignant tumor tissue. In a small subgroup of four patients, hypoxia related 18F-FMISO PET was acquired. These preliminary data support the utility of 18F-FET and rCBV as markers for viable malignant tumor tissue. With respect to hypoxia, more patient data and more sophisticated analyses are clearly needed.

Parinaz Massoumzadeh¹, Safa Najmi², Jonathan McConathy¹, Andrei Vlassenko¹, An Hongyu³, Yi Su¹, Daniel Marcus¹, Keith Rich⁴, and Tammie Benzinger^1
1Mallinckrodt Institute of Radiology, Washington University in St. Louis, School of Medicine, St. Louis, Missouri, United States, ²Department of of Neurology, Tabriz Medical University, Tabriz, East Azarbaijan, Iran, ³Department of Radiology, University of North Carolina, Chapel Hill, North Carolina, United States,⁴Neurological Surgery, Washington University in St. Louis, School of Medicine, St. Louis, Missouri, United States

Cerebral hypoxia can potentially impact treatment outcome and brain tumor patient survival. Preliminary results of a non-contrast oxygen sensitive magnetic resonance (MR) procedure for measuring brain and brain tumoral oxygen extraction fraction (OEF) are presented and compared with the results obtain using¹⁵O positron emission tomography (¹⁵O-PET) technique. Both MR and ¹⁵O-PET can measure OEF in brain tumors and in peritumoral edema, however, BOLD MR fails in regions with signal loss on SWI or T2*. Both techniques have tremendous potential and may offer new insight into the underlying physiology of brain tumors.

Nuno André da Silva¹, Liliana Lourenco Caldeira¹, Jörg Mauler¹, Hans Herzog¹, and N Jon Shah^1,2
1Institute of Neuroscience and Medicine - 4, Forschungszentrum Jülich, Jülich, Germany, ²JARA - Faculty of Medicine, RWTH Aachen University, Aachen, Germany

In this study we investigate an automatic segmentation of internal carotid arteries to obtain an image derived input function for data acquired in the MR-BrainPET. The excellent co-registration achieved with a simultaneous measurement is explored with an automatic segmentation method in order to reduce the workload and intra/inter-observer variability.

Manabu Kinoshita¹, Hideyuki Arita², Naoki Kagawa², Yoshiyuki Watanabe³, Jun Hatazawa⁴, Naoya Hashimoto², and Toshiki Yoshimine^2
1Neurosurgery, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka, Osaka, Japan, ²Neurosurgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan, ³Radiology, Osaka University Graduate School of Medicine, Suita, Osaka, Japan, ⁴Nuclear Medicine and Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan

Imaging and predicting tumor cell density or tumor cell invasion is challenging. The authors have compared diffusion tensor imaging (DTI) and 11C-methionine PET in terms of tumor cell density prediction by use of 98 stereotactically sampled glioma tissues from 37 patients. Tumor cell density showed a statistically significant positive correlation with MET-TNR (p<0.0001, R2=0.43) and negative correlation with rADC (p=0.0096, R2=0.09), while rFA did not correlate with tumor cell density. Multiple regression analysis revealed that MET-TNR was the solo statistically significant factor for tumor cell density prediction (MET-TNR: p<0.0001, rADC: p=0.06).

Benjamin M Ellingson^1,2, Robert J Harris³, William H Yong⁴, Whitney Pope³, Debiao Li⁵, Linda M Liau⁶, and Timothy F Cloughesy^7
1Radiology, UCLA, Los Angeles, CA, United States, ²Psychiatry & Biobehavioral Sciences, UCLA, CA, United States, ³Radiology, UCLA, CA, United States,⁴Pathology, UCLA, CA, United States, ⁵Biomedical Sciences and Imaging, Cedars-Sinai Medical Center, CA, United States, ⁶Neurosurgery, UCLA, CA, United States, ⁷Neurology, UCLA, CA, United States

A decrease in pH within the tumor microenvironment results in malignant transformation, resistance to radiation therapy, resistance to specific chemotherapies, increased probability of metastasis, immunosuppression, increased tumor invasion, increased rate of mutation, increased chromosomal rearrangements, altered gene expression, and angiogenesis. A non-invasive imaging method for evaluating tumor tissue pH will be valuable for early detection of treatment response, tumor progression, and/or treatment failure in malignant tumors. Our preliminary data suggests that chemical exchange saturation transfer (CEST) imaging, a new MRI technique, can be used to identify tumor tissue with low pH (acidic tissue) by targeting MR excitation of amine protons on glutamine, a major source of fuel for tumor cells.

Xiaolei Song¹, Yan Bai², Erning Zhang², Xiaowei He^1,3, Panli Zuo⁴, Dapeng Shi², Michael T. McMahon¹, Benjamin Schmitt⁵, and Meiyun Wang^2
1The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States, ²Department of Radiology, Henan Provincial People¡¯s Hospital, Zhengzhou, Henan, China, ³School of Information Sciences and Technology, Northwest University, Xi'an, Shaanxi, China, ⁴MR Collaborations NE Asia, Siemens Healthcare, Beijing, China, ⁵Healthcare Sector, Siemens Ltd Australia, Macquarie Park, Australia

We integrated a length and offset varied saturation (LOVARS) CEST method on a 3.0T MR scanner for improved APT imaging on patients with gliomas. Instead of sweeping different frequency offsets as conventional APT imaging, the LOVARS scheme collects only 2 offsets with different pre-saturation time for 3-4 cycles for improving CNR efficiency. In multiple patients with cerebral gliomas confirmed by histopathology, LOVARS phase maps clearly show improved CNR and well-defined tumor boundary, also reducing the total scan time and SAR effect. In addition, the phase contrast showed differences between patients, which may allow differentiation of tumor types as APT.

Melanie Morrison^1,2, Laleh Golestanirad^2,3, Fred Tam¹, Gregory Hare^4,5, Marco Garavaglia⁵, Simon Graham^1,2, and Sunit Das^4,6
1Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada, ²Medical Biophysics, University of Toronto, Toronto, Ontario, Canada, ³Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, Massachusetts, United States, ⁴Keenan Research Centre, St. Michael's Hospital, Toronto, Ontario, Canada, ⁵Department of Anesthesia, St. Michael's Hospital, Toronto, Ontario, Canada, ⁶Division of Neurosurgery, St. Michael's Hospital, Toronto, Ontario, Canada

Preoperative functional magnetic resonance imaging (fMRI) has been used to assist with the surgical management of glioma patients. This work presents initial experiences using preoperative fMRI in the treatment of 20 glioma patients. The influence of fMRI results on surgical planning has been assessed and fMRI activation maps have been validated with intraoperative mapping results via electrical stimulation. Positive outcomes of this work go towards encouraging the extended use of fMRI for neurosurgical application.

Kathleen M Schmainda¹, Melissa Prah², Leslie C Baxter³, Eric S Paulson⁴, Sharmeen Maze³, James Pipe³, Dingui Wang³, Josef Debbins³, and Leland Hu^5
1Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, ²Radiology, Medical College of Wisconsin, WI, United States, ³Barrow Neurological Institute, Phoenix, AZ, United States, ⁴Medical College of Wisconsin, WI, United States, ⁵Mayo Clinic, Scottsdale, AZ, United States

Previously the dual-echo gradient-echo spiral-based (DEGES) method proved to be one of the most accurate for the determination of relative cerebral blood volume (rCBV) values in brain tumors. The DEGES method also enables the simultaneous collection of DSC and DCE (dynamic contrast enhanced) data, all with just a single dose of gadolinium (Gd) contrast agent. This study demonstrates that DEGES provides results equivalent to those obtained with the more proven GRE-EPI DSC MRI methods. This motivates a more widespread evaluation and adoption of this approach for the collection of multiparameter perfusion data in brain tumors.

Jianrui Li¹, Qiang Xu², Zhiqiang Zhang¹, and Guangming Lu^1
1Medical Imaging, Jingling Hospital, School of Medicine, Nanjing University, Nanjing, Jiangsu, China, ²Medical Imaging, Jingling Hospital, School of Medicine, Nanjing, Jiangsu, China

Time-shift functional connectivity based resting-state fMRI has proven a non-invasive and effective tool for measuring hemodynamic property of brain, and has been applied to reflect perfusion abnormality in cerebral diseases, such as ischemic stroke [1], moya-moya disease [2] and epilepsy [3]. In this work, we preliminarily assessed the feasibility of this approach on diagnosis assessment of supratentorial glioma.