Combined T2* and T1 measurements for improved perfusion and permeability studies in high field using dynamic contrast enhancement.
This study analyzed the T2* effect of extracellularly distributed gadolinium contrast agents in arterial blood during tumor studies using T1-weighted sequences at high field strength. A saturation-prepared dual echo sequence with echo times of 1.5 and 3.5 ms was employed at 3 T to simultaneously characterize T1 and T2* of arterial blood during bolus administration of Gd-DTPA in 28 patients with body tumors. T2* effect and T1 effect of Gd-DTPA on image intensity of whole blood were calibrated in human blood samples with different concentrations of contrast agent. T2* was used to estimate concentration near the peak of the bolus. T1 was used to measure lower concentrations when T2* was not significant. T2* was measurable on calibration curves for Gd-DTPA concentrations higher than 4 mM. This concentration was exceeded in 18 patients. The mean signal intensity reduction because of T2* effect was estimated at 22+/-14% of the T2* compensated signal. Using T2* measurements reduced underestimations of peak arterial Gd-DTPA concentration (59 +/- 38%) and overestimation of permeability Ktrans (58%). The T2* effect of gadolinium contrast agents should therefore be accounted for when performing tumors study with T1-weighted sequences at high field strength.
Radiology Department, Saint Louis Hospital, 1 avenue Claude Vellefaux, 75475, Paris, Cedex 10, France. cedric.de-bazelaire@sls.aphp.fr
Cedric
C
de Bazelaire
Neil M
NM
Rofsky
Guillaume
G
Duhamel
Jingbo
J
Zhang
M Dror
MD
Michaelson
Daniel
D
George
David C
DC
Alsop
D001011:Aorta / Q000473:pathology; D002138:Calibration; D002292:Carcinoma, Renal Cell / Q000175:diagnosis* / Q000556:secondary; D003287:Contrast Media; D019786:Gadolinium DTPA / Q000097:blood / Q000493:pharmacokinetics*; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000556:secondary; D018810:Magnetic Resonance Angiography / Q000295:instrumentation / Q000379:methods*; D010539:Permeability; D019047:Phantoms, Imaging
D003287:Contrast Media; D019786:Gadolinium DTPA