Practical data acquisition method for human brain tumor amide proton transfer (APT) imaging.

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biomedical Engineering
• Neuro-oncology

Background:

• Amide proton transfer (APT) imaging detects endogenous proteins and peptides using chemical exchange-dependent saturation transfer (CEST) MRI.
• Previous APT studies showed promise for brain tumor detection but were limited by magnetic field inhomogeneity and low signal-to-noise ratio (SNR).

Purpose of the Study:

• To present a practical APT data acquisition scheme for B(0)-inhomogeneity corrected human brain imaging.
• To evaluate the clinical feasibility and diagnostic potential of APT imaging in brain tumor patients.

Main Methods:

• A six-offset APT data acquisition scheme was developed and combined with a separately acquired CEST spectrum.
• B(0)-inhomogeneity correction was applied to APT images.
• Data were acquired from nine brain tumor patients at 3T MRI.

Main Results:

• The new method provided sufficient SNR within a clinically relevant timeframe.
• APT intensities were significantly higher in the tumor core of high-grade tumors compared to contralateral normal-appearing white matter (CNAWM).
• APT intensities in low-grade tumors were indistinguishable from CNAWM.
• Increased APT signal extended beyond the tumor core in high-grade tumors.

Conclusions:

• The developed APT imaging technique offers improved SNR and B(0)-inhomogeneity correction for brain tumor assessment.
• APT imaging can differentiate high-grade from low-grade brain tumors.
• APT imaging has potential for accurate delineation of heterogeneous tumor areas in brain cancers.