Administration of contrast media before proton magnetic resonance spectroscopy ( ¹H MRS) may allow more accurate placement of the volume of interest in breast tumors, but some studies have suggested their use decreases the choline peak. We studied the impact of contrast use to determine which method would reduce the choline peak the least.
Phantoms containing 1,5, and 10mM concentrations of choline were prepared in phosphate-buffered saline and mixed with contrast media in concentrations of 0, 0.2, 0.4, and 0.6 mM. We used 2 different media: one being a negatively-charged diethylenetriaminepentaacetic acid gadolinium (Gd-DTPA), and the other a neutral gadoteridol (Gd-HP-DO3A). We studied all phantoms by single voxel ¹H MRS with a repetition time (TR) of 2,000 msec and an echo time (TE) of 136 or 270 msec.
Gd-DTPA tended to induce an increase in the peak integral and amplitude at lower concentrations and a decrease at a higher concentration, whereas Gd-HP-DO3A tended to induce an increase in the peak integral and amplitude at lower concentrations with no definite decrease at higher concentrations. Neither contrast medium induced a definite change in peak width. The reduction of the choline peak integral and amplitude at TE of 270 msec was greater than at TE of 136 msec.
Therefore, we recommend the use of the neutral contrast agent and short TE in ¹H MRS studies of breast tumors to avoid underestimation of the level of choline peaks.
