MRI may be used to improve accuracy of internal thermometer
Duke University chemists have developed a new way to measure temperature changes inside the body with "unprecedented precision" by correcting a subtle error in the original theory underlying MRI, according to a report published in the Oct. 17 issue of Science.
"We can get five to 10 times better accuracy in temperature maps than is possible with the best possible conventional methods," said corresponding author Warren S. Warren, a Duke chemistry professor. The new technique "is suitable for imaging temperature in a wide range of environments," the report said.
MRI is effective for imaging patients’ interior anatomies because hydrogen atoms in internal organs will broadcast their locations when subjected to selected radio waves in the presence of a strong, computer-programmable magnetic field, according to the report.
MRI scans can also be used to estimate interior temperature changes in procedures like hyperthermia cancer therapy because the hydrogen atoms in water shift their MRI broadcasting frequencies in a predictable way as water temperatures change.
Though precise in evaluating water temperature changes in isolation, conventional MRI works imperfectly as an internal thermometer within actual patients because the magnetic field's interactions with hydrogen atoms vary widely within patients' bodies, and those interactions also shift from minute to minute, Warren said.
“Current methods break down in the very systems that are of greatest interest, those that are inhomogeneous and that change with time," the authors wrote. “As a result, they only provide relative temperature maps,” Warren added. “So we're developing methods to do MRI differently.”
The Duke group's approach involves selective detection of intermolecular multiple quantum coherences (iMQCs) in hydrogen atoms. Warren said that the use of iMQCs is an application of his lab's 1998 correction of an early "subtle mistake" in the way MRI's inventors exploited quantum mechanical theory.
The technique could improve clinical applications of hyperthermia against cancer, and also be applied in other kinds of therapy, according to Warren. "Temperature regulation is an extremely important part of how biological processes in us work.”
The National Institutes of Health (NIH) funded the research.
"We can get five to 10 times better accuracy in temperature maps than is possible with the best possible conventional methods," said corresponding author Warren S. Warren, a Duke chemistry professor. The new technique "is suitable for imaging temperature in a wide range of environments," the report said.
MRI is effective for imaging patients’ interior anatomies because hydrogen atoms in internal organs will broadcast their locations when subjected to selected radio waves in the presence of a strong, computer-programmable magnetic field, according to the report.
MRI scans can also be used to estimate interior temperature changes in procedures like hyperthermia cancer therapy because the hydrogen atoms in water shift their MRI broadcasting frequencies in a predictable way as water temperatures change.
Though precise in evaluating water temperature changes in isolation, conventional MRI works imperfectly as an internal thermometer within actual patients because the magnetic field's interactions with hydrogen atoms vary widely within patients' bodies, and those interactions also shift from minute to minute, Warren said.
“Current methods break down in the very systems that are of greatest interest, those that are inhomogeneous and that change with time," the authors wrote. “As a result, they only provide relative temperature maps,” Warren added. “So we're developing methods to do MRI differently.”
The Duke group's approach involves selective detection of intermolecular multiple quantum coherences (iMQCs) in hydrogen atoms. Warren said that the use of iMQCs is an application of his lab's 1998 correction of an early "subtle mistake" in the way MRI's inventors exploited quantum mechanical theory.
The technique could improve clinical applications of hyperthermia against cancer, and also be applied in other kinds of therapy, according to Warren. "Temperature regulation is an extremely important part of how biological processes in us work.”
The National Institutes of Health (NIH) funded the research.