The objective of this work was to assess the feasibility and accuracy of T1 and relaxivity measurements in cell cultures using 1.5T magnetic resonance imaging (MRI) with the long-term goal to develop a tool for evaluation of novel paramagnetic agents in a realistic macromolecular environment. This initial study was carried out using MCF-7 cells treated with independently determined concentrations of Gd-DTPA. Two cell culture systems were evaluated: cell pellets and single layers of cells grown on microporous inserts. High-resolution T1 measurements of cell cultures were acquired with two dimensional Inversion Recovery Fast Spin Echo (2D-IR-FSE), three dimensional Inversion Recovery Fast Spin Echo (3D-IR-FSE), and 3D-SPGR sequences. The T1 and relaxivity accuracy of these sequences was confirmed with aqueous Gd-DTPA samples of known concentration. Relaxivities of 1.71 +/- 0.15 [mM(-1)second(-1)] and 1.55 +/- 0.50 [mM(-1)second(-1)] were measured in the cell pellets and cell monolayers, respectively, and were different from the value of 4.3 [mM(-1)second(-1)] for Gd-DTPA in water. Both cell pellets and monolayers are suitable for initial assessment of novel MR contrast agents.
Copyright 2001 Wiley-Liss, Inc.