title: Ocular MR imaging: evaluation of different coil setups in a phantom study.
abstract: OBJECTIVE
  Small loop surface coils are generally recommended for ocular magnetic resonance (MR) imaging, but the optimal coil setup has not been systematically investigated. In this phantom study, we investigated which coil setup of those coils available for our MR imaging system provides the highest signal-to-noise ratio (SNR) in ocular MR imaging at 1.5 tesla.
  
  
  METHODS
  Using a phantom to simulate the eyeball and the orbital fat, we employed loop surface coils of 4- and 6-cm diameter and a multi-channel head coil to obtain images using a T1-weighted spin-echo sequence and then measured the SNR for each coil and coil combination.
  
  
  RESULTS
  Use of the 6-cm loop coil alone yielded the highest mean SNR (27.5). Even in superficial regions (mesial and temporal), the SNR was higher using the 6-cm loop coil (33.6 and 45.5) than the 4-cm loop coil (28.0 and 33.8). Additional use of the head coil reduced the mean SNR to 10.4.
  
  
  CONCLUSIONS
  This quantitative analysis suggests that use of a 6-cm loop surface coil offers the best results in ocular MR imaging. Combinations of loop coils or additional use of a head coil cannot be recommended because higher noise degrades image quality.
authors.affiliation: Department of Radiology, Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin.
authors.forename: Katharina
authors.initials: K
authors.lastname: Erb-Eigner
authors.forename: Carsten
authors.initials: C
authors.lastname: Warmuth
authors.forename: Matthias
authors.initials: M
authors.lastname: Taupitz
authors.forename: Eckart
authors.initials: E
authors.lastname: Bertelmann
authors.forename: Bernd
authors.initials: B
authors.lastname: Hamm
authors.forename: Patrick
authors.initials: P
authors.lastname: Asbach
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D005123:Eye / Q000033:anatomy & histology*; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014159:Transducers