MRM Microcoil Performance Calibration and Usage Demonstrated on <em>Medicago truncatula</em> Roots at 22 T

This protocol describes a signal-to-noise ratio (SNR) calibration and sample preparation method for solenoidal microcoils combined with biological samples, designed high-resolution magnetic resonance imaging (MRI), also referred to as MR microscopy (MRM). It may be used at pre-clinical MRI spectrometers, demonstrated on Medicago truncatula root samples. Microcoils increase sensitivity by matching the size of RF resonator interest, thereby enabling higher image resolutions in given data acquisition time. Due relatively simple design, are straightforward cheap construct can easily adapted requirements. Systematically, we explain how calibrate new or home-built microcoils, using reference solution. The steps include: pulse power determination nutation curve; estimation RF-field homogeneity; calculating volume-normalized standard sequences. Important small samples discussed, well possible mitigating factors such susceptibility differences. applications an optimized solenoid coil (13 x 13 μm3, 2.2 pL) 3D sample.