title: Diffuse axonal injury at ultra-high field MRI.
abstract: OBJECTIVE
  Diffuse axonal injury (DAI) is a specific type of traumatic brain injury caused by shearing forces leading to widespread tearing of axons and small vessels. Traumatic microbleeds (TMBs) are regarded as a radiological marker for DAI. This study aims to compare DAI-associated TMBs at 3 Tesla (T) and 7 T susceptibility weighted imaging (SWI) to evaluate possible diagnostic benefits of ultra-high field (UHF) MRI.
  
  
  METHODS
  10 study participants (4 male, 6 female, age range 20-74 years) with known DAI were included. All MR exams were performed with a 3 T MR system (Magnetom Skyra) and a 7 T MR research system (Magnetom 7 T, Siemens AG, Healthcare Sector, Erlangen, Germany) each in combination with a 32-channel-receive coil. The average time interval between trauma and imaging was 22 months. Location and count of TMBs were independently evaluated by two neuroradiologists on 3 T and 7 T SWI images with similar and additionally increased spatial resolution at 7 T. Inter- and intraobserver reliability was assessed using the interclass correlation coefficient (ICC). Count and diameter of TMB were evaluated with Wilcoxon signed rank test.
  
  
  RESULTS
  Susceptibility weighted imaging revealed a total of 485 TMBs (range 1-190, median 25) at 3 T, 584 TMBs (plus 20%, range 1-262, median 30.5) at 7 T with similar spatial resolution, and 684 TMBs (plus 41%, range 1-288, median 39.5) at 7 T with 10-times higher spatial resolution. Hemorrhagic DAI appeared significantly larger at 7 T compared to 3 T (p = 0.005). Inter- and intraobserver correlation regarding the counted TMB was high and almost equal 3 T and 7 T.
  
  
  CONCLUSIONS
  7 T SWI improves the depiction of small hemorrhagic DAI compared to 3 T and may be supplementary to lower field strengths for diagnostic in inconclusive or medicolegal cases.
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors: Christoph
authors: C
authors: Moenninghoff
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors: Oliver
authors: O
authors: Kraff
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors: Stefan
authors: S
authors: Maderwald
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors: Lale
authors: L
authors: Umutlu
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors: Jens M
authors: JM
authors: Theysohn
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany.
authors: Adrian
authors: A
authors: Ringelstein
authors: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; Department of Neurosurgery, University Hospital Essen, Essen, Germany.
authors: Karsten H
authors: KH
authors: Wrede
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors: Cornelius
authors: C
authors: Deuschl
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany.
authors: Jan
authors: J
authors: Altmeppen
authors: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors: Mark E
authors: ME
authors: Ladd
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany.
authors: Michael
authors: M
authors: Forsting
authors: Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; High Field and Hybrid MR Imaging, University Hospital Essen, Essen, Germany.
authors: Harald H
authors: HH
authors: Quick
authors: Institute of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; Institute for Neuroradiology, University Hospital Giessen, Giessen, Germany.
authors: Marc
authors: M
authors: Schlamann
mesh_terms: D000328:Adult; D000368:Aged; D003710:Demography; D020833:Diffuse Axonal Injury / Q000150:complications / Q000175:diagnosis*; D005260:Female; D006801:Humans; D020300:Intracranial Hemorrhages / Q000150:complications / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D015203:Reproducibility of Results; D055815:Young Adult