title: Comparison of a 32-channel head coil and a 2-channel surface coil for MR imaging of the temporomandibular joint at 3.0 T.
abstract: OBJECTIVE
  To quantitatively and qualitatively compare MRI of the temporomandibular joint (TMJ) using a standard TMJ surface coil and a head coil at 3.0 T.
  
  
  METHODS
  22 asymptomatic volunteers were MR imaged using a 2-channel surface coil (standard TMJ coil) and a 32-channel head coil at 3.0 T (Philips Ingenia; Philips Healthcare, Netherlands). Imaging protocol consisted of an oblique sagittal proton density weighted turbo spin echo sequence (repetition time/echo time, 2700/26 ms). For quantitative assessment, a spherical phantom was imaged using the same sequence including a noise scan and a B1+ scan. Signal-to-noise ratio (SNR) maps and B1+ maps were calculated on a voxelwise basis. For qualitative evaluation, all volunteers underwent MRI of both TMJs with the jaw in the closed position. Two independent blinded readers assessed accuracy of TMJ anatomical representation and overall image quality on a 5-point scale. Quantitative and qualitative measurements were compared between coils using t-tests and Wilcoxon signed-rank test, respectively.
  
  
  RESULTS
  Quantitative analysis showed similar B1+ and significantly higher SNR for the head coil than the TMJ surface coil. Qualitative analysis showed significantly better visibility and delineation of clinically relevant anatomical structures of the TMJ, including the articular disc, bilaminar zone and lateral pterygoid muscle. Furthermore, better overall image quality was observed for the head coil than for the TMJ surface coil.
  
  
  CONCLUSIONS
  A 32-channel head coil is preferable to a standard 2-channel TMJ surface coil when imaging the TMJ at 3.0 T, because it yields higher SNR, thus increasing accuracy of the anatomical representation of the TMJ.
authors.affiliation: 1 Department of Radiology, Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Switzerland.|2 Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Switzerland.
authors.forename: Andrei
authors.identifier: http://orcid.org/0000-0003-1230-5752
authors.initials: A
authors.lastname: Manoliu
authors.affiliation: 2 Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Switzerland.
authors.forename: Georg
authors.initials: G
authors.lastname: Spinner
authors.affiliation: 2 Institute for Biomedical Engineering, University of Zurich and ETH Zurich, Switzerland.
authors.forename: Michael
authors.initials: M
authors.lastname: Wyss
authors.affiliation: 1 Department of Radiology, Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Switzerland.
authors.forename: Lukas
authors.initials: L
authors.lastname: Filli
authors.affiliation: 3 Center of Dental Medicine of the University of Zurich, Zurich, Switzerland.
authors.forename: Stefan
authors.initials: S
authors.lastname: Erni
authors.affiliation: 3 Center of Dental Medicine of the University of Zurich, Zurich, Switzerland.
authors.forename: Dominik A
authors.initials: DA
authors.lastname: Ettlin
authors.affiliation: 1 Department of Radiology, Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Switzerland.
authors.forename: Erika J
authors.initials: EJ
authors.lastname: Ulbrich
authors.affiliation: 1 Department of Radiology, Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Switzerland.
authors.forename: Felix P
authors.initials: FP
authors.lastname: Kuhn
authors.affiliation: 3 Center of Dental Medicine of the University of Zurich, Zurich, Switzerland.
authors.forename: Luigi M
authors.initials: LM
authors.lastname: Gallo
authors.affiliation: 1 Department of Radiology, Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, University of Zurich, Switzerland.
authors.forename: Gustav
authors.initials: G
authors.lastname: Andreisek
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000033:anatomy & histology; D004867:Equipment Design; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D019047:Phantoms, Imaging; D011446:Prospective Studies; D011626:Pterygoid Muscles / Q000033:anatomy & histology; D059629:Signal-To-Noise Ratio; D013704:Temporomandibular Joint / Q000033:anatomy & histology*; D019224:Temporomandibular Joint Disc / Q000033:anatomy & histology; D055815:Young Adult
keywords: joints; magnetic resonance imaging; signal-to-noise ratio; temporomandibular joint; temporomandibular joint disc
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