title: Semiquantitative assessment of optic nerve injury using manganese-enhanced MRI.
abstract: OBJECTIVE
  To evaluate the capability of manganese (Mn(2+))-enhanced MRI (MEMRI) in a continuously semiquantitative assessment of rat optic nerve (ON) injury.
  
  
  METHODS
  Forty rats were divided into three groups: (I) a control group that was submitted to MEMRI or to fluorescent labeling of retinal ganglion cells (RGCs) (n = 10); (II) an ON injury group that was submitted to MEMRI (n = 15); (III) an ON injury group that was submitted to fluorescent labeling of RGCs (n = 15). Groups II and III were examined at 3, 7, and 14 days post-lesion (dpl), when the contrast-to-noise ratio (CNR) of the retina and ON was measured on MEMRI images and the RGCs were counted by fluorescence microscopy and compared between the groups.
  
  
  RESULTS
  In the control group, the intact visual pathway from the retina to the contralateral superior colliculus was visualized by MEMRI. In group II, continuous Mn(2+) enhancement was seen from the retina to the lesion site of the optic nerves at 3, 7, and 14 dpl. However, no Mn(2+) enhancement was observed distal to the lesion site at those time points. The observed Mn(2+) enhancement proximal to the ON lesion site declined between 7 and 14 dpl. The decrease in Mn(2+)-enhanced signal intensity at these sites at 7 and 14 dpl when compared to that at 3 dpl was significant (P < 0.05). The RGC density dropped by 6.84, 45.31, and 72.36 % at 3, 7, and 14 dpl, respectively.
  
  
  CONCLUSIONS
  MEMRI can be used to evaluate the structural changes after optic nerve injury.
authors.affiliation: Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Yunnan Tumor Hospital, No. 519 Kunzhou Road, Xishan District, Kunming, 650118, Yunnan, People's Republic of China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Yunnan Tumor Hospital, No. 519 Kunzhou Road, Xishan District, Kunming, 650118, Yunnan, People's Republic of China.
authors.forename: Qinqing
authors.initials: Q
authors.lastname: Li
authors.affiliation: Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Yunnan Tumor Hospital, No. 519 Kunzhou Road, Xishan District, Kunming, 650118, Yunnan, People's Republic of China.
authors.forename: Mary
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Central Laboratory, The Second Affiliated Hospital of Kunming Medical University, No. 374 Dian-Mian Avenue, Kunming, 650101, Yunnan, People's Republic of China.
authors.forename: Xia
authors.initials: X
authors.lastname: Cao
authors.affiliation: Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Yunnan Tumor Hospital, No. 519 Kunzhou Road, Xishan District, Kunming, 650118, Yunnan, People's Republic of China.
authors.forename: Yingying
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Yunnan Tumor Hospital, No. 519 Kunzhou Road, Xishan District, Kunming, 650118, Yunnan, People's Republic of China.
authors.forename: Guanshun
authors.initials: G
authors.lastname: Wang
authors.affiliation: Department of Radiology, The Third Affiliated Hospital of Kunming Medical University, Yunnan Tumor Hospital, No. 519 Kunzhou Road, Xishan District, Kunming, 650118, Yunnan, People's Republic of China. 598687026@qq.com.
authors.forename: Chengde
authors.initials: C
authors.lastname: Liao
mesh_terms: D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008345:Manganese; D009900:Optic Nerve / Q000000981:diagnostic imaging; D020221:Optic Nerve Injuries / Q000000981:diagnostic imaging* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D003287:Contrast Media; D008345:Manganese
keywords: Fluoro-Gold; Magnetic resonance imaging; Manganese; Optic nerve injury