title: Segmentation and characterization of interscapular brown adipose tissue in rats by multi-parametric magnetic resonance imaging.
abstract: OBJECTIVE
  The aim was to auto-segment and characterize brown adipose, white adipose and muscle tissues in rats by multi-parametric magnetic resonance imaging with validation by histology and UCP1.
  
  
  METHODS
  Male Wistar rats were randomized into two groups for thermoneutral (n = 8) and cold exposure (n = 8) interventions, and quantitative MRI was performed longitudinally at 7 and 11 weeks. Prior to imaging, rats were maintained at either thermoneutral body temperature (36 ± 0.5 °C), or short term cold exposure (26 ± 0.5 °C). Neural network based automatic segmentation was performed on multi-parametric images including fat fraction, T2 and T2* maps. Isolated tissues were subjected to histology and UCP1 analysis.
  
  
  RESULTS
  Multi-parametric approach showed precise delineation of the interscapular brown adipose tissue (iBAT), white adipose tissue (WAT) and muscle regions. Neural network based segmentation results were compared with manually drawn regions of interest, and showed 96.6 and 97.1% accuracy for WAT and BAT respectively. Longitudinal assessment of the iBAT volumes showed a reduction at 11 weeks of age compared to 7 weeks. The cold exposed group showed increased iBAT volume compared to thermoneutral group at both 7 and 11 weeks. Histology and UCP1 expression analysis supported our imaging results.
  
  
  CONCLUSIONS
  Multi-parametric MR based neural network auto-segmentation provides accurate separation of BAT, WAT and muscle tissues in the interscapular region. The cold exposure improves the classification and quantification of heterogeneous BAT.
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore.
authors.forename: K N
authors.initials: KN
authors.lastname: Bhanu Prakash
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore.
authors.forename: Sanjay K
authors.initials: SK
authors.lastname: Verma
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore.
authors.forename: Jadegoud
authors.initials: J
authors.lastname: Yaligar
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore.
authors.forename: Julian
authors.initials: J
authors.lastname: Goggi
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore.
authors.forename: Venkatesh
authors.initials: V
authors.lastname: Gopalan
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore.
authors.forename: Swee Shean
authors.initials: SS
authors.lastname: Lee
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore.
authors.forename: Xianfeng
authors.initials: X
authors.lastname: Tian
authors.affiliation: Laboratory of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Singapore.
authors.forename: Shigeki
authors.initials: S
authors.lastname: Sugii
authors.affiliation: Department of Endocrinology, Tan Tock Seng Hospital, Singapore, Singapore.|Singapore Institute for Clinical Sciences, Singapore, Singapore.
authors.forename: Melvin Khee Shing
authors.initials: MK
authors.lastname: Leow
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore.
authors.forename: Kishore
authors.initials: K
authors.lastname: Bhakoo
authors.affiliation: Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, A*STAR, 11 Biopolis Way, #02-02 Helios, Singapore, 138667, Singapore. sendhil_velan@sbic.a-star.edu.sg.
authors.forename: Sendhil S
authors.initials: SS
authors.lastname: Velan
mesh_terms: D002001:Adipose Tissue, Brown / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D000818:Animals; D003080:Cold Temperature; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D064847:Multimodal Imaging / Q000379:methods*; D051381:Rats; D017208:Rats, Wistar; D015203:Reproducibility of Results; D012540:Scapula / Q000033:anatomy & histology / Q000000981:diagnostic imaging*; D012680:Sensitivity and Specificity; D012785:Shoulder Joint / Q000033:anatomy & histology / Q000000981:diagnostic imaging*
keywords: BAT; Cold-stimulation; MRI; Neural network; Segmentation; WAT