title: Characterization of the Growth of Deep and Subcortical White Matter Hyperintensity on MR Imaging: A Retrospective Cohort Study.
abstract: OBJECTIVE
  In elderly patients, deep and subcortical white matter hyperintense lesions are frequently observed on MRI; however, the growth process of these lesions is unclear. The aims of this retrospective cohort study were to elucidate the growth characteristics of deep and subcortical white matter hyperintense lesions, and to insight their etiology.
  
  
  METHODS
  We enrolled 103 patients (1610 lesions) whose deep and subcortical white matter hyperintense lesions were monitored for 3 or more years by MRI examination. The area of each hyperintense lesion was measured using a tracing method in the first and last MRI examinations. The annual rate of increase in the area of each lesion was calculated, and using the Pearson product-moment correlation coefficient the correlation between the annual rate of increase in area and the interval between the first and last MRI examinations was determined.
  
  
  RESULTS
  The paired t-test showed a significant increase in the mean area of all the deep and subcortical white matter hyperintense lesions between the first and last MRI examinations (P < 0.001). However, hyperintense lesions had decreased in the area or disappeared in 227 (14.1%) lesions in the last MRI examination, particularly in patients with diabetes. The mean annual rate of increase in area of all hyperintense lesions was 0.013 ± 0.021 cm2per year. The annual rate of increase in area and the interval between the first and last MRI examinations showed a weak negative correlation (r = -0.121; P < 0.01).
  
  
  CONCLUSIONS
  Decrease in the area and the disappearance of the subcortical white matter hyperintense lesions, and a decline in the annual rate of increase in the lesion area with time suggest that the interstitial fluid accumulation associated with dysfunctional drainage around the vessels may be involved in the possible etiologies of deep and subcortical white matter hyperintense lesions.
authors.affiliation: Department of Radiology, Ohshima Clinic.
authors.forename: Michito
authors.initials: M
authors.lastname: Adachi
authors.affiliation: Department of Radiology, Ohshima Clinic.
authors.forename: Takamichi
authors.initials: T
authors.lastname: Sato
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006801:Humans; D049292:Leukoaraiosis / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D066127:White Matter / Q000000981:diagnostic imaging* / Q000254:growth & development*
keywords: brain; leukoaraiosis; magnetic resonance imaging; retrospective cohort study