MRI estimation of contrast agent concentration in tissue using a neural network approach.
Using an MRI T(1) by multiple readout pulses (TOMROP) image set, an adaptive neural network (ANN) was trained to directly estimate the concentration of a contrast agent (CA), gadolinium-bovine serum albumin (Gd-BSA), in tissue. In nine rats implanted with a 9L cerebral tumor, MRI acquisition of TOMROP inversion-recovery data was followed by quantitative autoradiography (QAR) using radioiodinated serum albumin (RISA). QAR autoradiograms were used as a training set for the ANN. Precontrast and 25 min postcontrast TOMROP image sets were shown to the ANN in the form of a physical feature set related to 24 inversion-recovery images; QAR autoradiograms at 30 min after injection of RISA were taken as the training standard for the network. After training and optimization, the ANN produced a map of Gd-BSA concentration [g-moles/liter]. The prediction by the ANN of CA concentration at 25 min after injection was well correlated (r = 0.82, P < 0.0001) with the corresponding autoradiogram's measure of CA concentration.
Bagher-Ebadian
Hassan
H
Department of Neurology, Henry Ford Health System, Detroit, Michigan 48202, USA.
Nagaraja
Tavarekere N
TN
Paudyal
Ramesh
R
Whitton
Polly
P
Panda
Swayamprava
S
Fenstermacher
Joseph D
JD
Ewing
James R
JR
D000818:Animals; D019540:Area Under Curve; D001932:Brain Neoplasms / Q000098:blood supply / Q000175:diagnosis*; D003287:Contrast Media / Q000493:pharmacokinetics*; D004195:Disease Models, Animal; D007091:Image Processing, Computer-Assisted; D007457:Iodine Radioisotopes; D008279:Magnetic Resonance Imaging / Q000379:methods*; D016571:Neural Networks, Computer; D012372:ROC Curve; D051381:Rats; D011916:Rats, Inbred F344; D012710:Serum Albumin, Bovine / Q000493:pharmacokinetics*
D003287:Contrast Media; D007457:Iodine Radioisotopes; C058230:gadolinium-bovine serum albumin complex; D012710:Serum Albumin, Bovine