title: Quantifying subclinical central nervous lesions in primary antiphospholipid syndrome: the role of magnetization transfer imaging.
abstract: OBJECTIVE
  To define the role of magnetization transfer imaging (MTI) in detecting subclinical central nervous system (CNS) lesions in primary antiphospholipid syndrome (PAPS).
  
  
  METHODS
  Ten non-CNS PAPS patients were compared to 10 CNS PAPS patients and 10 age- and sex-matched controls. All PAPS patients met Sapporo criteria. All subjects underwent conventional MRI and complementary MTI analysis to compose histograms. CNS viability was determined according to the magnetization transfer ratio (MTR) by mean pixel intensity (MPI) and the mean peak height (MPH). Volumetric cerebral measurements were assessed by brain parenchyma factor (BPF) and total/cerebral volume.
  
  
  RESULTS
  MTR histograms analysis revealed that MPI was significantly different among groups (P < 0.0001). Non-CNS PAPS had a higher MPI than CNS PAPS (30.5 +/- 1.01 vs. 25.1 +/- 3.17 percent unit (pu); P < 0.05) although lower than controls (30.5 +/- 1.01 vs. 31.20 +/- 0.50 pu; P < 0.05). MPH in non-CNS PAPS (5.57 +/- 0.20% (1/pu)) was similar to controls (5.63 +/- 0.20% (1/pu), P > 0.05) and higher than CNS PAPS (4.71 +/- 0.30% (1/pu), P < 0.05). A higher peak location (PL) was also observed in the CNS PAPS group in comparison with the other groups (P < 0.0001). In addition, a lower BPF was found in non-CNS PAPS compared to controls (0.80 +/- 0.03 vs. 0.84 +/- 0.02 units; P < 0.05) but similar to CNS PAPS (0.80 +/- 0.03 vs. 0.79 +/- 0.05 units; P > 0.05).
  
  
  CONCLUSIONS
  Our findings suggest that non-CNS PAPS patients have subclinical cerebral damage. The long-termclinical relevance of MTI analysis in these patients needs to be defined by prospective studies.
authors.affiliation: Rheumatology Division, Medical School, University of São Paulo, São Paulo, Brazil.
authors.forename: Danieli Castro
authors.initials: DC
authors.lastname: Oliveira de Andrade
authors.forename: Eduardo Ferreira
authors.initials: EF
authors.lastname: Borba
authors.forename: Eloísa
authors.initials: E
authors.lastname: Bonfá
authors.forename: Jozélio
authors.initials: J
authors.lastname: Freire de Carvalho
authors.forename: Antônio
authors.initials: A
authors.lastname: José da Rocha
authors.forename: Antônio
authors.initials: A
authors.lastname: Carlos Maia
mesh_terms: D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood; D016736:Antiphospholipid Syndrome / Q000276:immunology / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging
chemical_list: D000974:Antibodies, Antinuclear