title: Evaluation of metabolite changes in visual cortex in diabetic retinopathy by MR-spectroscopy.
abstract: OBJECTIVE
  To evaluate metabolite changes in the visual cortex of diabetic patients with nonproliferative or proliferative diabetic retinopathy by Magnetic Resonance Spectroscopy (MRS).
  
  
  METHODS
  15 normal subjects (group 1), 15 patients with diabetes who did not have diabetic retinopathy (group 2), 15 patients with nonproliferative diabetic retinopathy (NPDR) (group 3), and 15 patients with proliferative diabetic retinopathy (PDR) (group 4) were included in the study. Furthermore, diabetic patients were divided into two groups according to HbA1c levels (Group A: 20 patients, HbA1c <8%; Group B: 20 patients, HbA1c >8%). In all cases' left visual cortex, amounts of N-acetyl-aspartate (NAA), choline (Cho), and creatine (Cr) were measured by MRS. NAA/Cr, Cho/Cr, and NAA/Cho ratios were calculated. Furthermore, all cases' complete blood count (CBC) and biochemical parameters were evaluated.
  
  
  RESULTS
  There was no statistically significant difference for NAA/Cr, Cho/Cr, and NAA/Cho ratios between groups 1, 2, 3, and 4 (P>0.05). However there was a statistically significant difference for NAA/Cr and NAA/Cho ratios between groups A and B (P<0.05). There was no statistically significant difference for Cho/Cr ratio between groups A and B (P>0.05).
  
  
  CONCLUSIONS
  Although NAA/Cr and NAA/Cho ratios decrease in the visual cortex while diabetic retinopathy progresses, these decreases are not statistically significant. While HbA1c levels increase, the NAA concentration decreases in the visual cortex which indicates neuronal loss. The metabolite changes in the visual cortex are associated with acute events rather than chronic.
authors.affiliation: State Hospital, Siirt, Turkey.
authors.forename: Ercan
authors.initials: E
authors.lastname: Ozsoy
authors.forename: Selim
authors.initials: S
authors.lastname: Doganay
authors.forename: Metin
authors.initials: M
authors.lastname: Dogan
authors.forename: Alpay
authors.initials: A
authors.lastname: Alkan
authors.forename: Penpe Gul
authors.initials: PG
authors.lastname: Firat
mesh_terms: D000328:Adult; D000368:Aged; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000000981:diagnostic imaging / Q000378:metabolism*; D003941:Diagnostic Techniques, Ophthalmological; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008297:Male; D008660:Metabolism / Q000502:physiology; D008875:Middle Aged; D011859:Radiography; D013997:Time Factors; D014793:Visual Cortex / Q000737:chemistry / Q000000981:diagnostic imaging* / Q000378:metabolism*