7T MR of intracranial pathology: Preliminary observations and comparisons to 3T and 1.5T

Purpose: There have been an increasing number of studies involving ultra‐high‐field 7T of intracranial pathology, however, comprehensive clinical studies of neuropathology at 7T still remain limited. 7T has the advantage of a higher signal‐to‐noise ratio and a higher contrast‐to‐noise ratio, compared to current low field clinical MR scanners. We hypothesized 7T applied clinically, may improve detection and characterization of intracranial pathology. Materials and methods: We performed an IRB‐approved 7T prospective study of patients with neurological disease who previously had lower field 3T and 1.5T. All patients underwent 7T scans, using comparable clinical imaging protocols, with the aim of qualitatively comparing neurological lesions at 7T with 3T or 1.5T. To qualitatively assess lesion conspicuity at 7T compared with low field, 80‐paired images were viewed by 10 experienced neuroradiologists and scored on a 5‐point scale. Inter‐rater agreement was characterized using a raw percent agreement and mean weighted kappa. Results: One‐hundred and four patients with known neurological disease have been scanned to date. Fifty‐five patients with epilepsy, 18 patients with mild traumatic brain injury, 11 patients with known or suspected multiple sclerosis, 9 patients with amyotrophic lateral sclerosis, 4 patients with intracranial neoplasm, 2 patients with orbital melanoma, 2 patients with cortical infarcts, 2 patients with cavernous malformations, and 1 patient with cerebral amyloid angiopathy. From qualitative observations, we found better resolution and improved detection of lesions at 7T compared to 3T. There was a 55% raw inter‐rater agreement that lesions were more conspicuous on 7T than 3T/1.5T, compared with a 6% agreement that lesions were more conspicuous on 3T/1.5T than 7T. Conclusion: Our findings show that the primary clinical advantages of 7T magnets, which include higher signal‐to‐noise ratio, higher contrast‐to‐noise ratio, smaller voxels and stronger susceptibility contrast, may increase lesion conspicuity, detection and characterization compared to low field 1.5T and 3T. However, low field which detects a plethora of intracranial pathology remains the mainstay for diagnostic imaging until limitations at 7T are addressed and further evidence of utility provided.

[1]  Rita Garbelli,et al.  Blurring in patients with temporal lobe epilepsy: clinical, high-field imaging and ultrastructural study. , 2012, Brain : a journal of neurology.

[2]  M. E. Ladd,et al.  Magnetic Resonance Imaging of Cranial Nerves at 7 Tesla , 2012, Clinical Neuroradiology.

[3]  S. Stuckey,et al.  Hyperintensity of the precentral gyral subcortical white matter and hypointensity of the precentral gyrus on fluid-attenuated inversion recovery: variation with age and implications for the diagnosis of amyotrophic lateral sclerosis. , 2007, AJNR. American journal of neuroradiology.

[4]  Oliver Speck,et al.  Cortical thickness determination of the human brain using high resolution 3T and 7T MRI data , 2013, NeuroImage.

[5]  Aymn Babiker,et al.  022CORTICAL SUPERFICIAL SIDEROSIS PRESENTING AS TIA MIMIC , 2016 .

[6]  Steen Moeller,et al.  T 1 weighted brain images at 7 Tesla unbiased for Proton Density, T 2 ⁎ contrast and RF coil receive B 1 sensitivity with simultaneous vessel visualization , 2009, NeuroImage.

[7]  Oliver Speck,et al.  Correction of B0-induced geometric distortion variations in prospective motion correction for 7T MRI , 2016, Magnetic Resonance Materials in Physics, Biology and Medicine.

[8]  P. Novak,et al.  High-resolution ultrahigh-field MRI of stroke. , 2005, Magnetic resonance imaging.

[9]  Jean-Claude Baron,et al.  Cortical superficial siderosis: detection and clinical significance in cerebral amyloid angiopathy and related conditions. , 2015, Brain : a journal of neurology.

[10]  Yifeng Du,et al.  Increased iron level in motor cortex of amyotrophic lateral sclerosis patients: An in vivo MR study , 2014, Amyotrophic lateral sclerosis & frontotemporal degeneration.

[11]  J. Gore,et al.  Magnetic resonance imaging of the cervical spinal cord in multiple sclerosis at 7T , 2016, Multiple sclerosis.

[12]  C. Fellner,et al.  Cortical T2 signal shortening in amyotrophic lateral sclerosis is not due to iron deposits , 2005, Neuroradiology.

[13]  Hongcheng Shi,et al.  Improved sensitivity of 3.0 Tesla susceptibility-weighted imaging in detecting traumatic bleeds and its use in predicting outcomes in patients with mild traumatic brain injury , 2015, Acta radiologica.

[14]  Peter R Luijten,et al.  The Spectrum of MR Detectable Cortical Microinfarcts: A Classification Study with 7-Tesla Postmortem MRI and Histopathology , 2015, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[15]  Oliver Kraff,et al.  High-Resolution MRI of the Human Parotid Gland and Duct at 7 Tesla , 2009, Investigative radiology.

[16]  P R Luijten,et al.  Imaging the Intracranial Atherosclerotic Vessel Wall Using 7T MRI: Initial Comparison with Histopathology , 2015, American Journal of Neuroradiology.

[17]  C Fellner,et al.  MRI-FLAIR images of the head show corticospinal tract alterations in ALS patients more frequently than T2-, T1- and proton-density-weighted images , 2001, Journal of the Neurological Sciences.

[18]  J. Zwanenburg,et al.  Clinical applications of 7 T MRI in the brain. , 2013, European journal of radiology.

[19]  W. Wick,et al.  Improved Brain Tumor Classification by Sodium MR Imaging: Prediction of IDH Mutation Status and Tumor Progression , 2016, American Journal of Neuroradiology.

[20]  Oliver Kraff,et al.  Imaging of adult astrocytic brain tumours with 7 T MRI: preliminary results , 2010, European Radiology.

[21]  J. Hogg Magnetic resonance imaging. , 1994, Journal of the Royal Naval Medical Service.

[22]  M. Schlamann,et al.  First Clinical Study on Ultra-High-Field MR Imaging in Patients with Multiple Sclerosis: Comparison of 1.5T and 7T , 2009, American Journal of Neuroradiology.

[23]  Neel Madan,et al.  New directions in clinical imaging of cortical dysplasias , 2009, Epilepsia.

[24]  Jeff H. Duyn,et al.  Iron Accumulation in Deep Cortical Layers Accounts for MRI Signal Abnormalities in ALS: Correlating 7 Tesla MRI and Pathology , 2012, PloS one.

[25]  H. Sakahara,et al.  Arterial Spin-Labeled Perfusion Imaging Reflects Vascular Density in Nonfunctioning Pituitary Macroadenomas , 2013, American Journal of Neuroradiology.

[26]  Tobias Kober,et al.  MP2RAGE, a self bias-field corrected sequence for improved segmentation and T1-mapping at high field , 2010, NeuroImage.

[27]  Mark Lowe,et al.  Optic Nerve Assessment Using 7-Tesla Magnetic Resonance Imaging , 2016, Ocular Oncology and Pathology.

[28]  Samuel Wiebe,et al.  Surgical outcomes in lesional and non-lesional epilepsy: A systematic review and meta-analysis , 2010, Epilepsy Research.

[29]  吉田敦,et al.  High resolution MRIによる乳癌広がり診断能の検討 , 2005 .

[30]  Oliver Kraff,et al.  Assessing a Dysplastic Cerebellar Gangliocytoma (Lhermitte-Duclos Disease) with 7T MR Imaging , 2010, Korean journal of radiology.

[31]  M. Ladd,et al.  Imaging of patients with hippocampal sclerosis at 7 Tesla: initial results. , 2010, Academic radiology.

[32]  B. Hargreaves,et al.  Variable‐rate selective excitation for rapid MRI sequences , 2004, Magnetic resonance in medicine.

[33]  C Fellner,et al.  Hyperintense and hypointense MRI signals of the precentral gyrus and corticospinal tract in ALS: A follow-up examination including FLAIR images , 2002, Journal of the Neurological Sciences.

[34]  Jeff H. Duyn,et al.  The future of ultra-high field MRI and fMRI for study of the human brain , 2012, NeuroImage.

[35]  E. Ringelstein,et al.  Lesion morphology at 7 Tesla MRI differentiates Susac syndrome from multiple sclerosis , 2012, Multiple sclerosis.

[36]  D Yves von Cramon,et al.  Diffuse axonal injury associated with chronic traumatic brain injury: evidence from T2*-weighted gradient-echo imaging at 3 T. , 2003, AJNR. American journal of neuroradiology.

[37]  Nikos Evangelou,et al.  3 Tesla and 7 Tesla MRI of multiple sclerosis cortical lesions , 2010, Journal of magnetic resonance imaging : JMRI.

[38]  Tiilay Keskin M. D.. Hiisamettin,et al.  MAGNETIC RESONANCE IMAGING OF THE CRANIAL NERVES , 2007 .

[39]  K. Uğurbil,et al.  Manipulation of image intensity distribution at 7.0 T: Passive RF shimming and focusing with dielectric materials , 2006, Journal of magnetic resonance imaging : JMRI.

[40]  Blake D. Niederhauser,et al.  High‐resolution 7T MRI of the human hippocampus in vivo , 2008, Journal of magnetic resonance imaging : JMRI.

[41]  A. Oliveira,et al.  Detection of corticospinal tract compromise in amyotrophic lateral sclerosis with brain MR imaging: relevance of the T1-weighted spin-echo magnetization transfer contrast sequence. , 2004, AJNR. American journal of neuroradiology.

[42]  T A Gennarelli,et al.  Prevalence of MR evidence of diffuse axonal injury in patients with mild head injury and normal head CT findings. , 1994, AJNR. American journal of neuroradiology.

[43]  M. E. Ladd,et al.  Brain tumours at 7T MRI compared to 3T—contrast effect after half and full standard contrast agent dose: initial results , 2014, European Radiology.

[44]  D. Leys,et al.  Superficial Siderosis of the Central Nervous System: A Post-Mortem 7.0-Tesla Magnetic Resonance Imaging Study with Neuropathological Correlates , 2013, Cerebrovascular Diseases.

[45]  W. Teeuwisse,et al.  Simulations of high permittivity materials for 7 T neuroimaging and evaluation of a new barium titanate‐based dielectric , 2012, Magnetic resonance in medicine.

[46]  Kawin Setsompop,et al.  A low power radiofrequency pulse for simultaneous multislice excitation and refocusing , 2014, Magnetic resonance in medicine.

[47]  Nadia Colombo,et al.  Type II focal cortical dysplasia: Ex vivo 7T magnetic resonance imaging abnormalities and histopathological comparisons , 2016, Annals of neurology.

[48]  Nadia Colombo,et al.  Type II FCD: ex vivo 7 Tesla MRI abnormalities and histopathological comparisons. , 2015 .

[49]  M. Tosetti,et al.  7T MRI in focal epilepsy with unrevealing conventional field strength imaging , 2016, Epilepsia.

[50]  Peter R Luijten,et al.  In Vivo Detection of Cerebral Cortical Microinfarcts with High-Resolution 7T MRI , 2013, Journal of cerebral blood flow and metabolism : official journal of the International Society of Cerebral Blood Flow and Metabolism.

[51]  R Retkute,et al.  Improved detection of focal cortical lesions using 7T magnetisation transfer imaging in patients with multiple sclerosis. , 2014, Multiple sclerosis and related disorders.

[52]  Yulin Ge,et al.  Seven-Tesla magnetic resonance imaging: new vision of microvascular abnormalities in multiple sclerosis. , 2008, Archives of neurology.

[53]  T. Naidich,et al.  Ultra-High-Field MR Neuroimaging , 2015, American Journal of Neuroradiology.

[54]  P. Phal,et al.  Qualitative comparison of 3-T and 1.5-T MRI in the evaluation of epilepsy. , 2008, AJR. American journal of roentgenology.

[55]  D Guerrero BRAIN TUMOURS , 1999, Nursing times.

[56]  N B Smith,et al.  New high dielectric constant materials for tailoring the B1+ distribution at high magnetic fields. , 2010, Journal of magnetic resonance.

[57]  Mike P. Wattjes,et al.  Clinical application of multi-contrast 7-T MR imaging in multiple sclerosis: increased lesion detection compared to 3 T confined to grey matter , 2013, European Radiology.

[58]  Stefan Maderwald,et al.  High-resolution anatomy of the human brain stem using 7-T MRI: improved detection of inner structures and nerves? , 2014, Neuroradiology.

[59]  G. Kerchner Ultra-high field 7T MRI: a new tool for studying Alzheimer's disease. , 2011, Journal of Alzheimer's disease : JAD.

[60]  Panagiotis Fotiadis,et al.  Cortical localization of microbleeds in cerebral amyloid angiopathy: an ultra high-field 7T MRI study. , 2014, Journal of Alzheimer's disease : JAD.

[61]  Greg Zaharchuk,et al.  Arterial Spin–Labeled Perfusion Imaging in Acute Ischemic Stroke , 2014, Stroke.

[62]  Oliver Speck,et al.  Correction of gradient nonlinearity artifacts in prospective motion correction for 7T MRI , 2015, Magnetic resonance in medicine.

[63]  Hugo J. Kuijf,et al.  High-resolution intracranial vessel wall MRI in an elderly asymptomatic population: comparison of 3T and 7T , 2016, European Radiology.

[64]  S Maderwald,et al.  Imaging of brain metastases of bronchial carcinomas with 7 T MRI - initial results. , 2010, RoFo : Fortschritte auf dem Gebiete der Rontgenstrahlen und der Nuklearmedizin.

[65]  Bertil Rydenhag,et al.  Long-term outcomes of epilepsy surgery in Sweden , 2013, Neurology.

[66]  R. Wiest,et al.  Comparison of Routine Brain Imaging at 3 T and 7 T , 2016, Investigative radiology.

[67]  Thoralf Niendorf,et al.  Ultrahigh-Field MRI in Human Ischemic Stroke – a 7 Tesla Study , 2012, PloS one.