Concurrent measurements of cerebral blood flow, sodium, lactate, and high‐energy phosphate metabolism using 19F, 23Na, 1H, and 31P nuclear magnetic resonance spectroscopy

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Abstract
A new NMR technique for nondestructive, noninvasive, nonradioactive concurrent measurements of blood flow and several energy‐dependent metabolites were applied to in situ cat brain during high cerebral blood flow states (seizures) and low flow states (carotid occlusion plus hemorrhagic shock). An inductively coupled, quadruple‐tuned surface coil with a 50‐ohm match at all relevant frequencies was used for both excitation and receiving. A broadband spectometer was used to measure the 31P spectrum (PCr, ATP, Pi, and pH), a water‐suppressed 1H spectrum (lactate), 23Na, and 19F (blood flow via CHF3 washout). Each nucleus was excited at an independently determined rate. Sodium, with a short T1, was excited more frequently than phosphorus. The results qualitatively agreed with other techniques. Blood flow greatly increased during seizures with a 10% decrease in the Na signal, minimal lactate accumulation, no pH shift, and a change in the PCr‐to‐Pi ratio from 3.4 to 1.7. During carotid occlusion plus hypotension blood flow, PCr and ATP decreased to less than 10% of baseline values. Changes in PCr and Pi preceded parallel changes in Na and ATP. These experiments demonstrated the feasibility of concurrent measurements of physiologically induced changes in high‐energy phosphates, lactate, sodium, and blood flow from the same volume of brain, in a nondestructive manner using NMR spectroscopy. © 1988 Academic Press, Inc.