Novel method of quantifying pulmonary vascular resistance by use of simultaneous invasive pressure monitoring and phase-contrast magnetic resonance flow.
BACKGROUND
Pulmonary vascular resistance (PVR) quantification is important in the treatment of children with pulmonary hypertension. The Fick principle, used to quantify pulmonary artery flow, may be a flawed technique. We describe a novel method of PVR quantification by the use of magnetic resonance (MR) flow data and invasive pressure measurements.


RESULTS
In 24 patients with either suspected pulmonary hypertension or congenital heart disease requiring preoperative assessment, PVR was calculated by the use of simultaneously acquired MR flow and invasive pressure measurements (condition 1). In 19 of the 24 patients, PVR was also calculated at 20 ppm nitric oxide +30% (condition 2) and at 20 ppm nitric oxide +100% oxygen (condition 3), with the use of the MR method. This method proved safe and feasible in all patients. In 15 of 19 patients, PVR calculated by Fick flow was compared with the MR method. At condition 1, Bland-Altman analysis revealed a bias of 2.3% (MR > Fick) and limits of agreement of 50.2% to -45.5%. At condition 2, there was poorer agreement (bias was 28%, and the limits of agreement were 151.3% to 95.2%). At condition 3, there was very poor agreement (bias was 54.2%, and the limits of agreement were 174.4% to -66.0%).


CONCLUSIONS
We have demonstrated the feasibility of using simultaneous invasive pressure measurements and MR flow data to measure PVR in humans.
Cardiac MR Research Group, Division of Imaging Sciences, King's College, London, United Kingdom.
Vivek
V
Muthurangu
Andrew
A
Taylor
Rado
R
Andriantsimiavona
Sanjeet
S
Hegde
Marc E
ME
Miquel
Robert
R
Tulloh
Edward
E
Baker
Derek L G
DL
Hill
Reza S
RS
Razavi
D000293:Adolescent; D000328:Adult; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D005240:Feasibility Studies; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D006976:Hypertension, Pulmonary / Q000175:diagnosis* / Q000503:physiopathology; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011652:Pulmonary Circulation; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012212:Rheology / Q000379:methods*; D012680:Sensitivity and Specificity; D014655:Vascular Resistance