title: Intensity correction method customized for multi-animal abdominal MR imaging with 3T clinical scanner and multi-array coil.
abstract: OBJECTIVE
  Simultaneous magnetic resonance (MR) imaging of multiple small animals in a single session increases throughput of preclinical imaging experiments. Such imaging using a 3-tesla clinical scanner with multi-array coil requires correction of intensity variation caused by the inhomogeneous sensitivity profile of the coil. We explored a method for correcting intensity that we customized for multi-animal MR imaging, especially abdominal imaging.
  
  
  METHODS
  Our institutional committee for animal experimentation approved the protocol. We acquired high resolution T₁-, T₂-, and T₂*-weighted images and low resolution proton density-weighted images (PDWIs) of 4 rat abdomens simultaneously using a 3T clinical scanner and custom-made multi-array coil. For comparison, we also acquired T₁-, T₂-, and T₂*-weighted volume coil images in the same rats in 4 separate sessions. We used software created in-house to correct intensity variation. We applied thresholding to the PDWIs to produce binary images that displayed only a signal-producing area, calculated multi-array coil sensitivity maps by dividing low-pass filtered PDWIs by low-pass filtered binary images pixel by pixel, and divided uncorrected T₁-, T₂-, or T₂*-weighted images by those maps to obtain intensity-corrected images. We compared tissue contrast among the liver, spinal canal, and muscle between intensity-corrected multi-array coil images and volume coil images.
  
  
  RESULTS
  Our intensity correction method performed well for all pulse sequences studied and corrected variation in original multi-array coil images without deteriorating the throughput of animal experiments. Tissue contrasts were comparable between intensity-corrected multi-array coil images and volume coil images.
  
  
  CONCLUSIONS
  Our intensity correction method customized for multi-animal abdominal MR imaging using a 3T clinical scanner and dedicated multi-array coil could facilitate image interpretation.
authors.affiliation: Functional Imaging Division, Research Center for Innovative Oncology, National Cancer Center Hospital East, Kashiwanoha 6-5-1, Kashiwa, Chiba 277-8577, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Mitsuda
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Ryutaro
authors.initials: R
authors.lastname: Nakagami
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Furuta
authors.forename: Norio
authors.initials: N
authors.lastname: Sekine
authors.forename: Mamoru
authors.initials: M
authors.lastname: Niitsu
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Moriyama
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Fujii
mesh_terms: D000005:Abdomen / Q000033:anatomy & histology*; D000465:Algorithms; D000818:Animals; D016477:Artifacts; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007089:Image Enhancement / Q000295:instrumentation* / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000662:veterinary*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software