J Korean Radiol Soc.  2001 Sep;45(3):277-284.

Proton MR Spectroscopic Features According to Change of Hepatic Parenchymal Iron Content after SPIO Injection

• Suh CH
• Cho SG
• Lim MK
• Kim MY
• Lee KH
• Kim HJ

Abstract

PURPOSE: To determine the effect of iron on proton MR spectra (1H-MRS) by evaluating changes in 1H-MRS of the liver according to changes in hepatic parenchymal iron content.
MATERIALS AND METHODS
We evaluated serial changes in 1H-MRS of the liver after intravenous infusion of SPIO in 40 rabbits. These were divided into eight groups of five, and in each group, respectively, 1H-MRS and T2WI MR images were acquired prior to SPIO infusion, just after infusion, and at 15 minutes and 1, 2, 4, 24 and 96 hours after infusion. MR spectra were evaluated with particular attention to the curve pattern observed at specific times after the infusion of SPIO, and the results were correlated with the signal intensity observed on T2W1 images and the histologic giade of ilon content of samples of resected liver parenchyma.
RESULTS
As observed on T2WI, the mean signal intensity of rabbit liver in its pre-SPIO infusion state, just after infusion, at 15 minutes, and at 1, 2, 4, 24 and 96 hours after SPIO infusion was 121.3 +/-15.5, 41.5 +/-12.7, 30.3 +/-7.9, 31.3 +/-3.5, 33.6 +/-9.4, 45.5 +/-10.9, 80.3 +/-15.7 and 110.4 +/-22.9, respectively(p<0.05). Mean standard deviation of the ratio of the area of the peak (3.9-4.1 ppm) / lipid peak (1.3 ppm) peak at each of the above times except for the pre-infusion state was 1.10 +/-0.13, 1.86 +/-0.21, 1.80 +/-0.30, 1.76 +/-0.27, 1.74 +/-0.20, 0.07 +/-0.02 and 0.03 +/-0.01, respectively(p<0.05). The hepatic parenchymal iron content increased rapidly from just after SPIO infusion, reaching its maximal level (as revealed by histologic specimens) at 15 minutes, sustaining this for up to 4 hours, and then decreasing gradually over periods of 24 and 96 hours. These results show that serial changes in patterns of MR spectra and the signal intensity seen on T2WI images correlate closely with changes in hepatic parenchymal iron content.
CONCLUSION
Elevated hepatic parenchymal iron content leads to increases in the relative intensity of unknown peaks at around 4.0 ppm and decreases in the relative intensity of lipid peaks.

Keyword

Magnetic resonance(MR), spectroscopy; Magnetic resonance(MR), contrast media; Magnetic resonance(MR), experimental studies; Liver, MR; Liver, iron content

MeSH Terms

Infusions, Intravenous
Iron*
Liver
Protons*
Rabbits
Iron
Protons