In vivo 31P magnetic resonance spectroscopy using a needle microcoil

Area of Science:

• Biomedical Engineering
• Medical Devices
• Magnetic Resonance Imaging

Background:

• Magnetic Resonance Spectroscopy (MRS) is crucial for metabolic analysis.
• Current MRS techniques often require expensive or complex instrumentation.
• Disposable microcoils offer a potential solution for cost-effective, targeted in vivo measurements.

Purpose of the Study:

• To develop and evaluate low-cost, disposable needle-shaped microcoils for in vivo MRS.
• To assess the feasibility of using these microcoils for metabolic profiling in biological tissues.
• To demonstrate the potential of needle microcoils in surgical and diagnostic applications.

Main Methods:

• Batch fabrication of needle-shaped microcoils using electroplated conductors embedded in silicon and plastic shafts.
• Acquisition of in vivo phosphorus-31 (31P) MRS spectra from rat thigh muscle at 81 MHz.
• Analysis of spectral data to determine signal-to-noise ratio (SNR) and detect metabolic changes.

Main Results:

• Achieved a maximum SNR of 10.4 for phosphocreatine (PCr) in a 10-min acquisition.
• Clearly visualized adenosine triphosphate (ATP) multiplets.
• Observed a 20% reduction in PCr over 60 minutes and estimated intracellular pH at 6.6, indicating ischemia.

Conclusions:

• Needle microcoils are effective for acquiring in vivo 31P MRS spectra.
• The developed microcoils can detect metabolic changes associated with ischemia.
• This technology holds promise for real-time MRS in surgical interventions and pathology evaluation.