Frequency Dependence of T1and T2Relaxation Times of Water in Normal and Tumoral Lung Tissues. T2Relaxation Time Evidence of Water Different Chemical Shifts and Exchange Rates

Autor:	Carmelo La Cognata, Alberto Tregnaghi, Flaviano Coletta
Rok vydání:	1994
Předmět:	Lung Proton Chemistry Chemical shift Relaxation (NMR) Spin–lattice relaxation Field dependence Atomic and Molecular Physics and Optics Analytical Chemistry Magnetic field Spin–spin relaxation medicine.anatomical_structure Nuclear magnetic resonance medicine Spectroscopy
Zdroj:	Spectroscopy Letters. 27:661-676
ISSN:	1532-2289 0038-7010
Popis:	Water 1H relaxation times, T1 and T2, have been measured at different magnetic fields for a total of 22 samples of normal and tumoral lung tissues taken away just after surgery. Results indicate that the average T1 values increase continuously with the inverse of the square root of the resonance frequency. The opposite trend is manifested for the average T2 values, which decrease continuously with the square of the frequency. We interpret the anomalous frequency dependence of T2 by introducing in the relationship a field dependent term. This term is indicative of the presence of a minimum of two kinds of water molecular surroundings in both normal and neoplastic lung tissues. The upper limits of the exchange rates are derived in this way. The values of these exchange rates are different for normal and neoplastic tissue.
Databáze:	OpenAIRE
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