title: Magnetic resonance-derived 3-dimensional blood flow patterns in the main pulmonary artery as a marker of pulmonary hypertension and a measure of elevated mean pulmonary arterial pressure.
abstract: BACKGROUND
  Pulmonary hypertension is a disease characterized by an elevation in pulmonary arterial pressure that is diagnosed invasively via right heart catheterization. Such pathological altered pressures in the pulmonary vascular system should lead to changes in blood flow patterns in the main pulmonary artery.
  
  
  RESULTS
  Forty-eight subjects (22 with manifest pulmonary hypertension, 13 with latent pulmonary hypertension, and 13 normal control subjects) underwent time-resolved 3D magnetic resonance phase-contrast imaging of the main pulmonary artery. Velocity fields that resulted from measurements were calculated, visualized, and analyzed with dedicated software. Main findings were as follows: (1) Manifest pulmonary hypertension coincides with the appearance of a vortex of blood flow in the main pulmonary artery (sensitivity and specificity of 1.00, 95% confidence intervals of 0.84 to 1.00 and 0.87 to 1.00, respectively), and (2) the relative period of existence of the vortex correlates significantly with mean pulmonary arterial pressure at rest (correlation coefficient of 0.94). To test the diagnostic performance of the vortex criterion, we furthermore investigated 55 patients in a blinded prospective study (22 with manifest pulmonary hypertension, 32 with latent pulmonary hypertension, and 1 healthy subject), which resulted in a sensitivity of 1.00 and specificity of 0.91 (95% confidence intervals of 0.84 to 1.00 and 0.76 to 0.98, respectively). Comparison of catheter-derived mean pulmonary artery pressure measurements and calculated mean pulmonary artery pressure values resulted in a standard deviation of differences of 3.6 mm Hg.
  
  
  CONCLUSIONS
  Vortices of blood flow in the main pulmonary artery enable the identification of manifest pulmonary hypertension. Elevated mean pulmonary arterial pressures can be measured from the period of vortex existence.
authors.affiliation: Siemens Medical Solutions, Graz, Austria. gert.reiter@siemens.com
authors.forename: Gert
authors.initials: G
authors.lastname: Reiter
authors.forename: Ursula
authors.initials: U
authors.lastname: Reiter
authors.forename: Gabor
authors.initials: G
authors.lastname: Kovacs
authors.forename: Bernhard
authors.initials: B
authors.lastname: Kainz
authors.forename: Karin
authors.initials: K
authors.lastname: Schmidt
authors.forename: Robert
authors.initials: R
authors.lastname: Maier
authors.forename: Horst
authors.initials: H
authors.lastname: Olschewski
authors.forename: Rainer
authors.initials: R
authors.lastname: Rienmueller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity; D001794:Blood Pressure; D006328:Cardiac Catheterization; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000503:physiopathology; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000503:physiopathology*; D011652:Pulmonary Circulation; D012039:Regional Blood Flow; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D055815:Young Adult