Purpose: (31)P MR spectroscopy (MRS) allows the noninvasive assessment of metabolic alterations in tumors. Due to physical as well as technical limitations, mostly large and single voxels are used. We used a spatially resolved (31)P MRS technique to characterize metabolic abnormalities inside and adjacent to liver metastases of patients with uvea melanoma.
Materials and methods: Optimization of 3D chemical shift imaging (3D CSI) was performed in healthy volunteers (n = 19; voxel size 25 ml). Patients (n = 8) with liver metastases were then examined. Cross sectional imaging was available for all patients.
Results: Compared to healthy volunteers, the PME/PDE ratios of patients with liver metastasis were significantly higher (0.56 +/- 0.30 vs. 0.39 +/- 0.21; p < 0.05). A trend towards increased PME/beta ATP ratios (2.07 +/- 1.83 vs. 1.02 +/- 0.45; p = 0.12) and decreased Pi/PME ratios (0.57 +/- 0.29 vs. 1.06 +/- 0.58; p = 0.06) was also observed. Patients with metastases > or = 5 cm showed significantly higher PME/PDE ratios (0.68 +/- 0.17 vs. 0.45 +/- 0.03; p < 0.05). Liver parenchyma adjacent to metastases did not show any significant changes compared to non-diseased tissue.
Conclusion: 3D CSI allows the simultaneous analysis of metabolic alterations in diseased as well as in healthy human liver. Metastases show significant metabolic alterations. Thus, (31)P MRS opens new possibilities for therapeutic monitoring.