phosphocreatine and Melanoma

(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.. 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.. 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.. 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.

Topics: Adenosine Triphosphate; Adult; Aged; Choroid Neoplasms; Energy Metabolism; Female; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Liver; Liver Neoplasms; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Male; Melanoma; Middle Aged; Observer Variation; Phosphocreatine; Phospholipids; Reference Values; Sensitivity and Specificity; Young Adult

31P MRS resonance ratios of tumors depend on the T1S of the phosphorus compounds. The objective of the 31P MRS study reported here was to investigate whether the phosphorus T1S of melanomas are influenced by the presence of melanin. One amelanotic (COX-t) and one melanotic (ROX-t) human melanoma xenograft line were studied at two different tumor volumes: 200 and 1000 mm3. 31P MRS was performed in nonanaesthetized mice at 4.7 T. The T1S were measured by using the superfast inversion recovery technique. Fraction of necrotic tissue in the tumors was determined by histological examination. The ROX-t tumors showed shorter T1S than the COX-t tumors at a volume of 200 mm3, where the fraction of necrotic tissue in the tumors was insignificant. The difference was similar in magnitude for all resonances. The T1S were not significantly different for COX-t and ROX-t at a volume of 1000 mm3, where the tumors of both lines had developed significant necrosis. The phosphorus T1S of melanomas without necrosis can be shortened significantly by the presence of melanin. The magnitude of the T1 shortening is similar for all major compounds. 31P MRS resonance ratios of melanomas are not altered significantly by correcting for effects of partial saturation.

Topics: Animals; Humans; Magnetic Resonance Spectroscopy; Male; Melanins; Melanoma; Mice; Mice, Inbred BALB C; Organophosphates; Phosphates; Phosphocreatine; Phosphorus; Transplantation, Heterologous; Tumor Cells, Cultured

Phosphorus spin-lattice relaxation times (T1s) were measured in vivo by 31P-nuclear magnetic resonance spectroscopy in tumors from four amelanotic human melanoma xenograft lines grown subcutaneously in BALB/c-nu/nu mice. The T1s were analyzed in relation to tumor volume, fractional tumor water content, and fraction of necrotic tumor tissue. The following resonances were studied: phosphomonoesters (PME), inorganic phosphate (Pi), phosphodiesters (PDE), phosphocreatine (PCr), and nucleoside triphosphates gamma, alpha, and beta (NTP gamma, alpha, and beta). Two different techniques were used to measure the T1s: superfast inversion recovery (SUFIR) and conventional inversion recovery (IR). The SUFIR and IR methods gave similar results. Tumors in the volume range 100-3000 mm3 were studied. The PME, Pi, PDE, and PCr resonances showed significantly longer T1s than the NTP gamma, alpha, and beta resonances at small tumor volumes. The T1s at small tumor volumes also differed significantly between the tumor lines. The T1s either decreased or remained unchanged with increasing tumor volume; the volume-dependence of the T1s differed significantly between the tumor lines but not between the resonances. Calculations based on the T1s measured here indicated that the errors in PCr/Pi and NTP beta/Pi resonance ratios due to partial saturation can vary with tumor volume but are usually < 20% at a repetition time of 2.0 s and < 15% at a repetition time of 3.0 s. There was no correlation between the T1s and fractional tumor water content.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Body Water; Humans; Magnetic Resonance Spectroscopy; Male; Melanoma; Mice; Mice, Inbred BALB C; Mice, Inbred Strains; Mice, Nude; Necrosis; Neoplasm Transplantation; Nucleotides; Phosphates; Phosphocreatine; Phosphorus; Transplantation, Heterologous

Topics: Antineoplastic Combined Chemotherapy Protocols; Chemotherapy, Cancer, Regional Perfusion; Cisplatin; Energy Metabolism; Female; Humans; Magnetic Resonance Spectroscopy; Melanoma; Melphalan; Middle Aged; Neoplasm Recurrence, Local; Phosphates; Phosphocreatine; Skin Neoplasms

A 1.4-T magnetic resonance (MR) imager was modified to perform MR spectroscopy measurements. The implementation involved only a few additions in hardware and practically no change in software. Procedures for acquiring the MR spectra are similar to those for MR images. Both sensitivity and homogeneity were found to be adequate over a region 12 cm in diameter. Typical scanning times are 4.5 minutes for human brain, 2.8 minutes for muscle, and 20-35 minutes for solid tumors. Preliminary spectral studies of the metabolism of human brains, tumors, and a muscle of the forearm during exercise obtained with the modified system are presented.

Topics: Adenosine Triphosphate; Adult; Animals; Brain; Carcinoma, Squamous Cell; Humans; Hydrogen-Ion Concentration; Magnetic Resonance Spectroscopy; Male; Melanoma; Mice; Muscle Contraction; Muscles; Phosphates; Phosphocreatine; Software; Tissue Extracts