title: Time-Dependent Changes in Dural Enhancement Associated With Spontaneous Intracranial Hypotension.
abstract: OBJECTIVE
  The objective of our study was to determine whether the presence of individual imaging signs of spontaneous intracranial hypotension (SIH) is correlated with increasing duration of headache symptoms. Of particular interest is the relationship of symptom duration to dural enhancement because it is the most commonly identified imaging sign in patients with SIH.
  
  
  METHODS
  Eighty-nine patients with SIH who underwent pretreatment brain MRI and total-spine CT myelography and whose medical record included data on the duration of clinical symptoms were included in this cross-sectional retrospective study. Brain imaging was reviewed for the presence of dural enhancement, brain sagging, and the "venous distention" sign. CT myelograms were assessed for CSF leak. If present, a leak was subcategorized as a high-flow or low-flow leak. Differences in headache duration between subjects with and those without individual imaging signs were compared.
  
  
  RESULTS
  Subjects without dural enhancement on brain MRI had a longer average duration of symptoms than those with dural enhancement present (average symptom duration: 45.3 ± 59.0 [SD] vs 15.1 ± 33.0 weeks, respectively; p = 0.002). No difference in symptom duration was observed between subjects whose MRI studies showed and those whose MRI studies did not show brain sagging (p = 0.10) or the venous distention sign (p = 0.21). The presence of a CSF leak on CT myelography was not associated with symptom duration (p = 0.56) except in the subgroup of patients with low-flow leaks.
  
  
  CONCLUSIONS
  Increasing symptom duration in SIH is associated with decreased prevalence of abnormal dural enhancement on brain MRI. Because dural enhancement is considered a hallmark imaging feature of this condition, its absence may exacerbate the problem of underdiagnosis in chronic cases of SIH.
authors.affiliation: 1 Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710.
authors.forename: Peter G
authors.initials: PG
authors.lastname: Kranz
authors.affiliation: 1 Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Amrhein
authors.affiliation: 1 Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710.
authors.forename: Kingshuk Roy
authors.initials: KR
authors.lastname: Choudhury
authors.affiliation: 1 Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710.
authors.forename: Teerath Peter
authors.initials: TP
authors.lastname: Tanpitukpongse
authors.affiliation: 1 Department of Radiology, Duke University Medical Center, Box 3808, Durham, NC 27710.
authors.forename: Linda
authors.initials: L
authors.lastname: Gray
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D004388:Dura Mater / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006261:Headache / Q000175:diagnosis* / Q000209:etiology; D006801:Humans; D019585:Intracranial Hypotension / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013997:Time Factors; D055815:Young Adult
keywords: CSF leak; CT myelography; brain MRI; spontaneous intracranial hypotension