title: Transverse dural sinuses: incidence of anatomical variants and flow artefacts with 2D time-of-flight MR venography at 1 Tesla.
abstract: OBJECTIVE
  This study sought to identify imaging criteria useful in discriminating anatomical variants from thrombosis of the posterior intracranial venous system.
  
  
  METHODS
  A total of 102 patients underwent coronal unenhanced two-dimensional time-of-flight (2D ToF) magnetic resonance (MR) venography. Transverse sinus (TS) calibre and asymmetry were considered. Oval (O-FG) and linear (L-FG) flow gaps were recorded. Several slices of the 2D ToF sequence were applied perpendicularly to the TS within each FG to avoid in-plane saturation.
  
  
  RESULTS
  Mean calibre of the right TS was significantly greater than the contralateral sinus (6.5 mm+/-1.84 vs 5.1 mm+/-1.72). Right and left dominance was observed in 61% and 17% of cases, respectively. The mean right-left TS diameter was 5.77 mm. Among 204 TS, 44 L-FG and 42 O-FG were observed. Partial L-FG (<2/3 of TS) never involved the distal TS. No L-FG was observed in a dominant TS. Supplementary sagittal 2D ToF images disclosed blood flow in all but two L-FGs. O-FGs were mostly observed laterally (91%).
  
  
  CONCLUSIONS
  L-FGs in a dominant TS, partial L-FGs in the distal part or O-FG in the medial part of any TS, a left-right mean diameter <3 mm and absence of flow even in ToF images perpendicular to the direction of blood flow should raise the suspicion of sinus pathology.
authors.affiliation: Neuroradiologic Unit, Department of Neurosciences, University of Padua, Via Giustiniani 2, 35128, Padova, Italy. renzo.manara@sanita.padova.it
authors.forename: R
authors.initials: R
authors.lastname: Manara
authors.forename: R
authors.initials: R
authors.lastname: Mardari
authors.forename: M
authors.initials: M
authors.lastname: Ermani
authors.forename: M S
authors.initials: MS
authors.lastname: Severino
authors.forename: L
authors.initials: L
authors.lastname: Santelli
authors.forename: C
authors.initials: C
authors.lastname: Carollo
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D001783:Blood Flow Velocity; D002550:Cerebral Veins / Q000473:pathology*; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003392:Cranial Sinuses / Q000473:pathology*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012851:Sinus Thrombosis, Intracranial / Q000175:diagnosis*