title: Age-related change in renal corticomedullary differentiation: evaluation with noncontrast-enhanced steady-state free precession (SSFP) MRI with spatially selective inversion pulse using variable inversion time.
abstract: OBJECTIVE
  To evaluate age-related change in renal corticomedullary differentiation and renal cortical thickness by means of noncontrast-enhanced steady-state free precession (SSFP) magnetic resonance imaging (MRI) with spatially selective inversion recovery (IR) pulse.
  
  
  METHODS
  The Institutional Review Board of our hospital approved this retrospective study and patient informed consent was waived. This study included 48 patients without renal diseases who underwent noncontrast-enhanced SSFP MRI with spatially selective IR pulse using variable inversion times (TIs) (700-1500 msec). The signal intensity of renal cortex and medulla were measured to calculate renal corticomedullary contrast ratio. Additionally, renal cortical thickness was measured.
  
  
  RESULTS
  The renal corticomedullary junction was clearly depicted in all patients. The mean cortical thickness was 3.9 ± 0.83 mm. The mean corticomedullary contrast ratio was 4.7 ± 1.4. There was a negative correlation between optimal TI for the best visualization of renal corticomedullary differentiation and age (r = -0.378; P = 0.001). However, there was no significant correlation between renal corticomedullary contrast ratio and age (r = 0.187; P = 0.20). Similarly, no significant correlation was observed between renal cortical thickness and age (r = 0.054; P = 0.712).
  
  
  CONCLUSIONS
  In the normal kidney, noncontrast-enhanced SSFP MRI with spatially selective IR pulse can be used to assess renal corticomedullary differentiation and cortical thickness without the influence of aging, although optimal TI values for the best visualization of renal corticomedullary junction were shortened with aging.
authors.affiliation: Department of Radiology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Noda
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kanki
authors.forename: Akira
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Hiroki
authors.initials: H
authors.lastname: Higashi
authors.forename: Daigo
authors.initials: D
authors.lastname: Tanimoto
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Sato
authors.forename: Atsushi
authors.initials: A
authors.lastname: Higaki
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Tamada
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Ito
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology* / Q000502:physiology*; D005260:Female; D006801:Humans; D007672:Kidney Cortex / Q000033:anatomy & histology* / Q000254:growth & development*; D007679:Kidney Medulla / Q000033:anatomy & histology* / Q000254:growth & development*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000502:physiology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: MRI; aging; corticomedullary differentiation; kidney; steady-state free precession (SSFP)