Dynamic contrast-enhanced MRI using Gd-DTPA: interindividual variability of the arterial input function and consequences for the assessment of kinetics in tumors.
Gd-DTPA kinetics in arterial blood was investigated by dynamic MRI in 47 patients with malignant and benign mammary tumors. Signal enhancement was monitored for 10 min after the beginning of a 1-min infusion of 0.1 mmol/kg Gd-DTPA. Kinetics in blood was biexponential with median half-lives of 21 sec and 11.1 min, respectively. Peak signal enhancement and the area under the signal enhancement-time curve varied 2.5- and 3.7-fold between patients. The shortest mean residence time in one of up to three tumor compartments, MRT*, was estimated using either the individual (reference) or a mean population (surrogate) arterial input function (AIF). MRT* (reference estimate) was 1.0 (0-1.5), 1.9 (1.5-2.3), and 2.5 (2.3-2.8) min in carcinomas, fibroadenomas, and mastopathies, respectively (median and interquartile distance). Surrogate estimates were unbiased but differed from the reference estimates 1.5-fold or more in 23% of cases. AIFs should be monitored individually if accurate estimates of individual MRT* are desired.
Port
R E
RE
Diagnostics and Experimental Therapy, German Cancer Research Center, Heidelberg, Germany. r.port@dkfz.de
Knopp
M V
MV
Brix
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G
D001943:Breast Neoplasms / Q000097:blood / Q000098:blood supply* / Q000175:diagnosis; D002277:Carcinoma / Q000097:blood / Q000098:blood supply* / Q000175:diagnosis; D003287:Contrast Media / Q000493:pharmacokinetics; D003937:Diagnosis, Differential; D005260:Female; D018226:Fibroadenoma / Q000097:blood / Q000098:blood supply* / Q000175:diagnosis; D019786:Gadolinium DTPA / Q000493:pharmacokinetics; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008833:Microcirculation / Q000503:physiopathology; D012039:Regional Blood Flow / Q000502:physiology
D003287:Contrast Media; D019786:Gadolinium DTPA