title: Validation of Perfusion Quantification with 3D Gradient Echo Dynamic Contrast-Enhanced Magnetic Resonance Imaging Using a Blood Pool Contrast Agent in Skeletal Swine Muscle.
abstract: The purpose of our study was to validate perfusion quantification in a low-perfused tissue by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) with shared k-space sampling using a blood pool contrast agent. Perfusion measurements were performed in a total of seven female pigs. An ultrasonic Doppler probe was attached to the right femoral artery to determine total flow in the hind leg musculature. The femoral artery was catheterized for continuous local administration of adenosine to increase blood flow up to four times the baseline level. Three different stable perfusion levels were induced. The MR protocol included a 3D gradient-echo sequence with a temporal resolution of approximately 1.5 seconds. Before each dynamic sequence, static MR images were acquired with flip angles of 5°, 10°, 20°, and 30°. Both static and dynamic images were used to generate relaxation rate and baseline magnetization maps with a flip angle method. 0.1 mL/kg body weight of blood pool contrast medium was injected via a central venous catheter at a flow rate of 5 mL/s. The right hind leg was segmented in 3D into medial, cranial, lateral, and pelvic thigh muscles, lower leg, bones, skin, and fat. The arterial input function (AIF) was measured in the aorta. Perfusion of the different anatomic regions was calculated using a one- and a two-compartment model with delay- and dispersion-corrected AIFs. The F-test for model comparison was used to decide whether to use the results of the one- or two-compartment model fit. Total flow was calculated by integrating volume-weighted perfusion values over the whole measured region. The resulting values of delay, dispersion, blood volume, mean transit time, and flow were all in physiologically and physically reasonable ranges. In 107 of 160 ROIs, the blood signal was separated, using a two-compartment model, into a capillary and an arteriolar signal contribution, decided by the F-test. Overall flow in hind leg muscles, as measured by the ultrasound probe, highly correlated with total flow determined by MRI, R = 0.89 and P = 10-7. Linear regression yielded a slope of 1.2 and a y-axis intercept of 259 mL/min. The mean total volume of the investigated muscle tissue corresponds to an offset perfusion of 4.7mL/(min ⋅ 100cm3). The DCE-MRI technique presented here uses a blood pool contrast medium in combination with a two-compartment tracer kinetic model and allows absolute quantification of low-perfused non-cerebral organs such as muscles.
authors.affiliation: Department of Radiotherapy, Medical Physics, University Hospital Essen, Essen, North Rhine-Westphalia, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Hindel
authors.affiliation: Department of Radiotherapy, Medical Physics, University Hospital Essen, Essen, North Rhine-Westphalia, Germany.
authors.forename: Anika
authors.initials: A
authors.lastname: Sauerbrey
authors.affiliation: Department of General and Visceral Surgery at Evangelical Hospital Wesel, Wesel, North Rhine-Westphalia, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Maaß
authors.affiliation: Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, North Rhine-Westphalia, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Maderwald
authors.affiliation: Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, North Rhine-Westphalia, Germany.
authors.forename: Marc
authors.initials: M
authors.lastname: Schlamann
authors.affiliation: Department of Radiotherapy, Medical Physics, University Hospital Essen, Essen, North Rhine-Westphalia, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Lüdemann
mesh_terms: D000818:Animals; D001810:Blood Volume; D003287:Contrast Media / Q000008:administration & dosage / Q000032:analysis; D005260:Female; D006614:Hindlimb / Q000098:blood supply / Q000000981:diagnostic imaging; D007089:Image Enhancement / Q000379:methods / Q000592:standards; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000000981:diagnostic imaging; D010477:Perfusion / Q000379:methods; D015203:Reproducibility of Results; D013552:Swine; D014463:Ultrasonography
chemical_list: D003287:Contrast Media