Dual Component Analysis for In Vivo T2* Decay of Hyperpolarized 13C Metabolites
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Purpose: To investigate the exchange and redistribution of hyperpolarized 13C metabolites between different pools by temporally analyzing the relative fraction of dual T2* components of hyperpolarized 13C metabolites. Materials and Methods: A dual exponential decay analysis of T2* is performed for [1-13C] pyruvate and [1-13C] lactate using nonspatially resolved dynamic 13C MR spectroscopy from mice brains with tumors (n = 3) and without (n = 4) tumors. The values of shorter and longer T2* components are explored when fitted from averaged spectrum and temporal variations of their fractions. Results: The T2* values were not significantly different between the tumor and control groups, but the fraction of longer T2* [1-13C] lactate components was more than 10% in the tumor group over that of the controls (P < 0.1). The fraction of shorter T2* components of [1-13C] pyruvate showed an increasing tendency while that of the [1-13C] lactate was decreasing over time. The slopes of the changing fraction were steeper for the tumor group than the controls, especially for lactate (P < 0.01). In both pyruvate and lactate, the fraction of the shorter T2* component was always greater than the longer T2* component over time. Conclusion: The exchange and redistribution of pyruvate and lactate between different pools was investigated by dual component analysis of the free induction decay signal from hyperpolarized 13C experiments. Tumor and control groups showed differences in their fractions rather than the values of longer and shorter T2* components. Fraction changing dynamics may provide an aspect for extravasation and membrane transport of pyruvate and lactate, and will be useful to determine the appropriate time window for acquisition of hyperpolarized 13C images.
Abstract
Purpose: To investigate the exchange and redistribution of hyperpolarized 13C metabolites between different pools by temporally analyzing the relative fraction of dual T2* components of hyperpolarized 13C metabolites. Materials and Methods: A dual exponential decay analysis of T2* is performed for [1-13C] pyruvate and [1-13C] lactate using nonspatially resolved dynamic 13C MR spectroscopy from mice brains with tumors (n = 3) and without (n = 4) tumors. The values of shorter and longer T2* components are explored when fitted from averaged spectrum and temporal variations of their fractions. Results: The T2* values were not significantly different between the tumor and control groups, but the fraction of longer T2* [1-13C] lactate components was more than 10% in the tumor group over that of the controls (P < 0.1). The fraction of shorter T2* components of [1-13C] pyruvate showed an increasing tendency while that of the [1-13C] lactate was decreasing over time. The slopes of the changing fraction were steeper for the tumor group than the controls, especially for lactate (P < 0.01). In both pyruvate and lactate, the fraction of the shorter T2* component was always greater than the longer T2* component over time. Conclusion: The exchange and redistribution of pyruvate and lactate between different pools was investigated by dual component analysis of the free induction decay signal from hyperpolarized 13C experiments. Tumor and control groups showed differences in their fractions rather than the values of longer and shorter T2* components. Fraction changing dynamics may provide an aspect for extravasation and membrane transport of pyruvate and lactate, and will be useful to determine the appropriate time window for acquisition of hyperpolarized 13C images.
참고문헌 (12)
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