title: Sulcal hyperintensity on fluid-attenuated inversion recovery mr images in patients without apparent cerebrospinal fluid abnormality.
abstract: OBJECTIVE
  Failure to suppress cerebrospinal fluid (CSF) signal intensity (sulcal hyperintensity) on fluid-attenuated inversion recovery (FLAIR) images has been reported in patients with abnormal CSF, such as those with meningitis and subarachnoid hemorrhage. Our study investigates the clinical history and MR findings associated with sulcal hyperintensity on FLAIR images in patients without apparent CSF abnormality.
  
  
  METHODS
  Three hundred consecutive MR imaging examinations were prospectively screened for patients with sulcal hyperintensity on FLAIR images. Nine patients with clinical, CT, or laboratory evidence suggesting abnormal CSF were excluded. The distribution of sulcal hyperintensity on FLAIR images and associated abnormal enhancement were evaluated. The presence of the "dirty CSF" sign (mild increase in CSF signal on unenhanced T1-weighted images or mild decrease on T2-weighted images) in the corresponding hyperintense sulcus was also assessed.
  
  
  RESULTS
  Twenty-six (8.9%) of the 291 patients had sulcal hyperintensity (16 focal, 10 diffuse) associated with 18 masses (6.1%) and eight vascular abnormalities (2.7%). Sulcal hyperintensity was frequently associated with the dirty CSF sign (69.2%) and abnormal contrast enhancement (overall, 96.2%; 88.5%, leptomeningeal; 53.8%, vascular enhancement).
  
  
  CONCLUSIONS
  Our study shows that sulcal hyperintensity on FLAIR imaging can occur in patients without apparent CSF abnormality. Its frequent association with mass effect, vascular disease, abnormal vascular enhancement, and dirty CSF sign suggests that an increase in blood pool, a small amount of protein leakage, and the "flow-entering" phenomenon of the congested blood may contribute to sulcal hyperintensity on FLAIR images.
authors.affiliation: Department of Radiology, Magnetic Resonance Imaging Center, University of Iowa College of Medicine, 200 Hawkins Dr., Iowa City, IA 52242, USA.
authors.forename: T
authors.initials: T
authors.lastname: Taoka
authors.forename: W T
authors.initials: WT
authors.lastname: Yuh
authors.forename: M L
authors.initials: ML
authors.lastname: White
authors.forename: J P
authors.initials: JP
authors.lastname: Quets
authors.forename: J E
authors.initials: JE
authors.lastname: Maley
authors.forename: T
authors.initials: T
authors.lastname: Ueda
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000473:pathology; D002555:Cerebrospinal Fluid; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies