Sebastian Ley MD, Presenter: Nothing to Disclose

Roland Unterhinninghofen, Abstract Co-Author: Nothing to Disclose

Julia Ley-Zaporozhan MD, Abstract Co-Author: Nothing to Disclose

Gabor Szabo MD, PhD, Abstract Co-Author: Nothing to Disclose

Hans-Ulrich Kauczor MD, Abstract Co-Author: Research grant, Siemens AG Research grant, Toshiba Corporation

Phase-contrast flow (pc-flow) measurements are an established technique for non-invasive assessment of hemodynamics of the systemic and pulmonary arterial circulation. However, in-vivo validation data on the accuracy of pc-flow are missing. The goal of our work was to correlate pc-flow with perivascular ultrasound (US) in different hemodynamic conditions.

Five healthy pigs with opened chest were investigated. US measurements were performed outside the MRI unit using a detachable MR-table. Parallel to US measurements invasive pressure measurements were performed. PC-flow measurements were done in a 1.5T MRI using a FLASH 2D sequence with a temporal resolution of approximately 20ms. All measurements were performed in the ascending aorta (Ao) and main pulmonary artery (MPA). First the animals were examined in normotonia, followed by hypertension (infusion of Arterenol) and hypotension (infusion of Sodiumnitropussid).

Systolic pressure in the Ao were 91mmHg (normotonia), 111mmHg (hypertonic) and 64mmHg (hypotonic) and 23mmHg (normotonia), 29mmHg (hypertonic) and 20mmHg (hypotonic) in the MPA. Flow measurements acquired in normotonia showed no difference (p=0.17) for US (2.7±0.6L/min) and MRI (2.8±0.6L/min). During hypertension the blood flow increased to 3.1±0.7 and 2.7±0.8L/min respectively (significant difference between US and MRI, p=0.01). During hypotension the blood flow decreased to 1.7±0.5 and 1.7±0.5L/min respectively (not significantly different, p=0.7). An excellent linear correlation between the US and MRI measurements was found (r=0.89). Systolic pressure measurements showed good linear correlation with MRI average flow per minute and peak velocity; r=0.79 for Ao and r=0.66 for MPA).

MRI pc-flow measurements are a reliable tool for non-invasive assessment of blood flow. Hemodynamic parameters measured by MRI allow for assessment of pressure estimates in the systemic and pulmonary arterial circulation.

Phase contrast flow measurements showed high correlation with perivascular ultrasound and thus are an accurate non-invasive method for determination of hemodynamic parameters

Ley, S, Unterhinninghofen, R, Ley-Zaporozhan, J, Szabo, G, Kauczor, H, Accuracy of MRI Phase Contrast Flow Measurements in Comparison to Perivascular Ultrasound in a Large Animal Model in the Systemic and Pulmonary Arterial Circulation.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5013828.html