1H NMR spectroscopy of subcutaneous tumors in mice: preliminary studies of effects of growth, chemotherapy and blood flow reduction.
This study evaluates a number of methods for obtaining 1H NMR spectra with adequate suppression of lipid and water resonances in two subcutaneously implanted transplantable tumor models (RIF-1 and EMT6/SF). Spin-echo spectra with long TEs (270 ms; water suppressed by presaturation) eliminated lipid resonances from 1H spectra of RIF-1 and decreased lipid contamination in spectra of EMT6/SF; however, spectral sensitivity was substantially reduced. A shorter TE (135 ms) increased sensitivity but did not result in adequate suppression of the lipid peaks. In RIF-1, but not EMT6/SF, adequate lipid suppression was achieved by: (i) spatially selective presaturation of lipid, which in this tumor (but not in EMT6/SF) was localized in a thin region along the periphery of the tumor, followed by a 1-D spin-echo chemical shift imaging pulse sequence (TE = 135 ms); and (ii) 2-D spin-echo chemical shift imaging (TE = 270 ms; approximately 2 x 2 x 9 mm3 voxels). Preliminary 1H studies of the RIF-1 tumor indicate that: (i) there are no significant changes in metabolite levels relative to tumor water during 4 days of untreated tumor growth; (ii) tumor response to chemotherapy with 5-fluorouracil results in a decrease in intensity of all metabolite 1H resonances relative to tumor water, with total choline decreasing the most and lactate the least; and (iii) acute tumor blood flow reduction induced by administration of hydralazine results in doubling of the lactate intensity relative to water.(ABSTRACT TRUNCATED AT 250 WORDS)
Shungu
D C
DC
Department of Radiology, Johns Hopkins School of Medicine, Baltimore, MD 21205.
Bhujwalla
Z M
ZM
Wehrle
J P
JP
Glickson
J D
JD
D000818:Animals; D002455:Cell Division; D005472:Fluorouracil / Q000627:therapeutic use; D006830:Hydralazine / Q000627:therapeutic use; D008055:Lipids / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy / Q000295:instrumentation; D051379:Mice; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D011522:Protons; D012039:Regional Blood Flow / Q000187:drug effects; D012983:Soft Tissue Neoplasms / Q000098:blood supply / Q000175:diagnosis* / Q000188:drug therapy / Q000473:pathology
D008055:Lipids; D011522:Protons; D006830:Hydralazine; D005472:Fluorouracil