title: Imaging-Based Features of Headaches in Chiari Malformation Type I.
abstract: BACKGROUND
  Suboccipital cough-induced headaches are considered a hallmark symptom of Chiari malformation type I (CMI). However, non--Valsalva-related suboccipital headaches and headaches in other locations are also common in CMI. The diagnostic significance and the underlying factors associated with these different headaches types are not well understood.
  
  
  OBJECTIVE
  To compare cranial morphology and hydrodynamics in 3 types of headaches in CMI to better understand the pathophysiological basis for the different headache characteristics.
  
  
  METHODS
  Twenty-two cranial physiological and morphological measures were obtained with specialized magnetic resonance imaging scans from 63 symptomatic pretreated CMI patients, 40 with suboccipital headaches induced by Valsalva maneuvers (34 women; age, 36 ± 10 years), 15 with non--Valsalva-related suboccipital headaches (10 women; age, 33 ± 9 years), 8 with nonsuboccipital non--Valsalva-induced headaches (8 women; age, 39 ± 13 years), and 37 control subjects (24 women; age, 36 ± 12 years). Group differences were identified with the use of the 2-tailed Student t test.
  
  
  RESULTS
  Posterior cranial fossa markers of CMI were similar among the 3 headache subtypes. However, the Valsalva-related suboccipital headaches cohort demonstrated a significantly lower intracranial compliance index than the non--Valsalva-related suboccipital headaches cohort (7.5 ± 3.4 vs 10.9 ± 4.9), lower intracranial volume change during the cardiac cycle (0.48 ± 0.19 vs 0.61 ± 0.16 mL), and higher magnetic resonance imaging--derived intracranial pressure (11.1 ± 4.3 vs 7.7 ± 2.8 mm Hg; P = .02). The Valsalva-related suboccipital headaches cohort had smaller intracranial and lateral ventricular volumes compared with the healthy cohort. The non--Valsalva-related suboccipital headaches cohort had reduced venous drainage through the jugular veins.
  
  
  CONCLUSIONS
  Valsalva-induced worsening of occipital headaches appears to be related to a small intracranial volume rather than the smaller posterior cranial fossa. This explains the reduced intracranial compliance and corresponding higher pressure measured in CMI patients with headaches affected by Valsalva maneuvers.
authors: *Department of Radiology and ‖Department of Neurological Surgery, University of Miami, Miami, Florida; ‡Institute of Clinical Radiology, Ludwig-Maximilian University, Munich, Germany; §Neurological Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania; ¶Department of Neurosurgery, Rush University, Chicago, Illinois.
authors: Noam
authors: N
authors: Alperin
authors: James R
authors: JR
authors: Loftus
authors: Carlos J
authors: CJ
authors: Oliu
authors: Ahmet M
authors: AM
authors: Bagci
authors: Sang H
authors: SH
authors: Lee
authors: Birgit
authors: B
authors: Ertl-Wagner
authors: Raymond
authors: R
authors: Sekula
authors: Terry
authors: T
authors: Lichtor
authors: Barth A
authors: BA
authors: Green
mesh_terms: D000328:Adult; D001139:Arnold-Chiari Malformation / Q000150:complications* / Q000473:pathology* / Q000503:physiopathology; D005260:Female; D006261:Headache / Q000209:etiology* / Q000473:pathology* / Q000503:physiopathology; D006801:Humans; D057446:Hydrodynamics; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D014636:Valsalva Maneuver