Quantitative 3D pulmonary MR-perfusion in patients with pulmonary arterial hypertension: correlation with invasive pressure measurements.
OBJECTIVE
Pathological changes of the peripheral pulmonary arteries induce pulmonary arterial hypertension (PAH). Aim of this study was to quantitatively assess the effect of PAH on pulmonary perfusion by 3D-MR-perfusion techniques and to compare findings to healthy controls. Furthermore, quantitative perfusion data were correlated with invasive pressure measurements.


METHODS
Five volunteers and 20 PAH patients (WHO class II or III) were examined using a 1.5T MR scanner. Measurement of pulmonary perfusion was done in an inspiratory breathhold (FLASH3D; 3.5 mm x 1.9 mm x 4mm; TA per 3D dataset 1.5s). Injection of contrast media (0.1 mmol Gd-DTPA/kg BW) and image acquisition were started simultaneously. Evaluation of 3D perfusion was done using singular value decomposition. Lung borders were outlined manually. Each lung volume was divided into three regions (anterior, middle, posterior), and the following parameters were assessed: Time-to-Peak (TTP), blood flow (PBF), blood volume (PBV), and mean transit time (MTT). In 10 patients invasive pulmonary artery pressure measurements were available and correlated to the perfusion measurements.


RESULTS
In both, controls and patients, an anterior-to-posterior gradient with higher PBF and PBV posterior was observed. In the posterior lung region, a significant difference (p<0.05) was found for TTP (12s versus 16s) and MTT (4s versus 6s) between volunteers and patients. PBF and PBV were lower in patients than in volunteers (i.e. dorsal regions: 124 versus 180 ml/100 ml/min and 10 versus 12 ml/100 ml), but the difference failed to be significant. The ratio of PBF and PBV between the posterior and the middle or ventral regions showed no difference between both groups. A moderate linear correlation between mean pulmonary arterial pressure (mPAP) and PBV (r=0.51) and MTT (r=0.56) was found.


CONCLUSIONS
The only measurable effect of PAH on pulmonary perfusion is a prolonging of the MTT. There is only a moderate linear correlation of invasive mPAP with PBV and MTT.
Ley
Sebastian
S
Department of Pediatric Radiology, Children's Hospital University Heidelberg, Im Neuenheimer Feld 153, 69120 Heidelberg, Germany. ley@gmx.net
Mereles
Derliz
D
Risse
Frank
F
Grünig
Ekkehard
E
Ley-Zaporozhan
Julia
J
Tecer
Zueleyha
Z
Puderbach
Michael
M
Fink
Christian
C
Kauczor
Hans-Ulrich
HU
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D016022:Case-Control Studies; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D021621:Imaging, Three-Dimensional; D008168:Lung / Q000098:blood supply / Q000473:pathology; D018810:Magnetic Resonance Angiography; D008297:Male; D008875:Middle Aged; D011652:Pulmonary Circulation; D012039:Regional Blood Flow / Q000502:physiology; D012984:Software
D003287:Contrast Media; D019786:Gadolinium DTPA