title: Postural effect on the size of the cisterna chyli.
abstract: BACKGROUND
  The aim was to investigate the effect of patient position on the size of the cisterna chyli using positional MRI. The cisterna chyli is usually the only large lymphatic vessel that can be found on cross-sectional imaging. Not much is known about its postural behavior. However, animal studies suggest that the cisterna chyli varies in size according to physical activity.
  
  
  RESULTS
  Retrospectively, 998 MRI scans of patients referred for positional MRI were reviewed. Ten patients had acquired axial scans in at least two positions at the level T12/L1 or/and L1/2 and were included in the study. The area representing the cisterna chyli was assessed on axial images and its size was compared in different positions. The size of the cisterna chyli determined as the cross-sectional area was 14.7 mm² ± 17.3 mm² in the supine position, 43.8 mm² ± 3.1 mm² in the sitting position, and 62.9 mm² ± 42.5 mm² in the standing position. Using the t-test, a statistically significant difference was found in the size of the cistern chyli between supine and standing positions and between supine and sitting positions.
  
  
  CONCLUSIONS
  The size of the cisterna chyli shows postural variations. This finding is discussed in regards to possible implications of interventional procedures in the thoracic duct. Physicians reading MR images acquired in positions other than supine should be aware of these physiological changes.
authors.affiliation: Privatpraxis für Upright MRT, Köln, Germany. p.niggemann@mrt-koeln.de
authors.forename: Pascal
authors.initials: P
authors.lastname: Niggemann
authors.forename: Andreas
authors.initials: A
authors.lastname: Förg
authors.forename: Dieter
authors.initials: D
authors.lastname: Grosskurth
authors.forename: Hans-Konrad
authors.initials: HK
authors.lastname: Beyer
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011187:Posture; D011877:Radionuclide Imaging; D012189:Retrospective Studies; D013897:Thoracic Duct / Q000033:anatomy & histology* / Q000000981:diagnostic imaging