title: The striated MR nephrogram, not a reflection of pathology.
abstract: BACKGROUND
  We have intermittently observed low signal striations in the kidneys on delayed post-contrast MR exams of the spine. While we suspected these striations were due to concentrated gadolinium, the clinical importance of this finding was uncertain.
  
  
  OBJECTIVE
  To describe the striated MR nephrogram (low signal striations in the kidney) and assess its clinical relevance.
  
  
  METHODS
  Retrospective review of delayed post-contrast MRIs of the spine (mean: 45 min after contrast administration). The presence of the striated MR nephrogram was correlated with imaging parameters (field strength, time since contrast), and findings (gadolinium in the bladder, inferior vena cava and aorta diameters) and with clinical factors (history of renal disease, laboratory values).
  
  
  RESULTS
  Seven hundred seventy-three exams performed on 229 patients, 8.3 ± 5.3 years of age, were reviewed. The striated MR nephrogram was observed in 102/773 examinations (13.2%) and was present on at least one study in 54/229 patients (23.6%). The presence of striations was associated with the specific magnet on which the exam was performed (P < 0.01) but not with magnet field strength. Serum creatinine was minimally lower in patients with striations (0.43 ± 0.12 vs. 0.49 ± 0.18 mg/dL, P = 0.002), but no other clinical or historical data, including time from contrast administration (P = 0.54), fluid status (P = 0.17) and clinical history of renal disease (P = 0.14), were predictive of the presence of striations.
  
  
  CONCLUSIONS
  The striated MR nephrogram was observed in 13% of delayed post-contrast MR exams of the spine. Precipitating factors are unclear, but the striated nephrogram does not appear to be a marker of clinically apparent renal dysfunction.
authors.affiliation: Department of Radiology - MLC 5031, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229, USA. andrew.trout@cchmc.org.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Trout
authors.affiliation: Division of Biostatistics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.affiliation: Department of Radiology - MLC 5031, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229, USA.
authors.forename: Marguerite M
authors.initials: MM
authors.lastname: Care
authors.affiliation: Department of Radiology - MLC 5031, Cincinnati Children's Hospital Medical Center, 3333 Burnet Ave., Cincinnati, OH, 45229, USA.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Towbin
mesh_terms: D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D005119:Extravasation of Diagnostic and Therapeutic Materials / Q000453:epidemiology* / Q000473:pathology*; D005260:Female; D006801:Humans; D033162:Incidental Findings; D007223:Infant; D007231:Infant, Newborn; D007668:Kidney / Q000473:pathology; D007674:Kidney Diseases / Q000453:epidemiology* / Q000473:pathology*; D008297:Male; D009820:Ohio / Q000453:epidemiology; D015203:Reproducibility of Results; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013122:Spinal Diseases / Q000453:epidemiology* / Q000473:pathology*
keywords: Children; Contrast; Gadolinium; Kidney; Magnetic resonance imaging; Renal function; Striated MR nephrogram