title: Idiopathic Parkinson disease effect of levodopa on apparent diffusion coefficient value of the brain.
abstract: OBJECTIVE
  To evaluate the effect of levodopa on apparent diffusion coefficient (ADC) value of the brain parenchyma in patients with idiopathic Parkinson disease (PD).
  
  
  METHODS
  Prospective study was conducted on native PD without treatment (n = 25) and patients receiving levodopa (L-Dopa) (n = 25). Diffusion magnetic resonance-weighted imaging was done using a single-shot spin echo type of echo planar imaging. The apparent diffusion coefficient (ADC) value at different regions of the brain on both sides was calculated.
  
  
  RESULTS
  The ADC value of the putamen in patients with native PD was 0.732 ± 0.15 × 10-3 mm2/seconds and in patients receiving levodopa was 0.789 ± 0.24 × 10-3 mm2/second. There was a statistically significant difference in the ADC value at the putamen (P = .001) between patients with native PD and patients receiving levodopa. When ADC value of the putamen at 0.745 × 10-3 mm2/second was used as a threshold value for differentiating native PD patients and patients receiving L-Dopa, the best results were obtained with an accuracy of 82%, sensitivity of 92%, specificity of 72%, positive predictive value of 77%, negative predictive value of 90%, and area under the curve of 0.955.
  
  
  CONCLUSIONS
  ADC value of the putamen is a promising parameter for predication of effect of levodopa on brain parenchyma in patients with PD.
authors.affiliation: Department of Diagnostic Radiology, Mansoura University, Egypt. arazek@mans.edu.eg
authors.forename: Ahmed Abdel Khalek Abdel
authors.initials: AA
authors.lastname: Razek
authors.forename: Azza
authors.initials: A
authors.lastname: Elmongy
authors.forename: Maha
authors.initials: M
authors.lastname: Hazem
authors.forename: Shirin
authors.initials: S
authors.lastname: Zakareyia
authors.forename: Wael
authors.initials: W
authors.lastname: Gabr
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D001921:Brain / Q000187:drug effects / Q000473:pathology; D001931:Brain Mapping / Q000379:methods; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D010300:Parkinson Disease / Q000188:drug therapy* / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016896:Treatment Outcome
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa