Abstract
Equivalent cross-relaxation rate (ECR) imaging (ECRI) is a measurement method that can be used to quantitatively evaluate a change in the protein-water interaction by MRI. The aim of this study is to evaluate utility of ECRI as an in vivo molecular imaging for living tissue such as lymph node. Fifteen patients with histologically confirmed invasive ductal carcinomas of the breast were studied. We adopted the off-resonance technique for preferential saturation of the immobile protons to evaluate the ECR values. The single saturation transfer pulse frequency was employed at the frequency 5 ppm downfield from the water resonance. The ECR value was defined as the percentage of single loss between unsaturated and saturated images. The ECRI was constructed on the basis of the percentage of ECR. The normal lymph node organization showed there were a large number of the cell and higher ECR value. On the other hand, the lymph nodes with metastases showed a small amount of the cell and a lower ECR value, and adipose tissue was almost no cells and the lowest ECR value. A statistically significant difference was observed in the ECR values of each tissue, and both numerical values were present on the first correlation line. In axillary lymph nodes with or without metastases, ECR value was well related to the number of the cell. Therefore, ECRI might be a potentially useful method for molecular imaging in tissue characterization of the lymph nodes. [J Physiol Sci. 2007;57 Suppl:S120]
