Quantitative analyses of correlations of signal intensity on T1-weighted images and T1 relaxation time with copper concentration in the rat liver

Rationale and Objectives. To evaluate the effects of intrahepatic copper on magnetic resonance (MR) images, we studied the signal intensity (SI) of T1-weighted images and the T1 relaxation time of Long-Evans Cinnamon (LEC) rats, which have abnormal copper metabolism, and compared them with those of Sprague-Dawley (SD) rats. Methods. We imaged the livers of four LEC rats before they developed hepatitis and four SD rats. The SI ratio of the liver to a phantom of polyvinyl alcohol gel was measured on T1-weighted images, and the T1 relaxation time was obtained from calculated T1 images. Copper concentration was measured by atomic absorption spectrophotometry. Results. The mean copper concentrations in the liver of LEC rats were approximately 20-fold and statistically higher than in SD cats. There was no significant difference in the SI ratio and the T1 relaxation time between the LEC and SD rats. Conclusion. Intrahepatic copper does not significantly influence either the SI of T1-weighted MR images or the T1 relaxation time of the rat liver.