Unilateral NMR devices are a valuable tool in various applications such as non-destructive testing or well logging, but are not applied routinely for biomedical imaging. A low cost, unilateral and portable MRI can introduce MRI into clinical applications previously non-feasible, exploiting the advantages of the open architecture, the portability and affordable costs of these scanners. However, the inhomogeneity of B0 in these scanners [1] results in a poor signal to noise ratio (SNR), and forces the use of the relatively slow scan-schemes and long averaging times. Improving the SNR of scans with Unilateral NMR is therefore a key factor as it can reduce the total scan time (by reducing the need in averaging repetitions). This may allow the implementation of additional methods to accelerate imaging. We suggest a novel post-processing method to improve the SNR of the acquired signal in unilateral NMR scanners. We estimate the signal parameters from the noisy data with the weighted least square (LS) approach, and exploit more efficiently the inherently known characteristics of the NMR signal. The method was first developed and tested for T2 measurements with a CPMG-like sequence applied in a unilateral scanner. Then, using a similar concept we further developed this method to improve the SNR of lateral slice–selective imaging scans specific to the unilateral scanner.
Bergman, E., Yeredor, A., & Nevo, U. (2013). An estimation method of MR signal parameters for improved image reconstruction in unilateral scanner. Journal of Magnetic Resonance, 237, 92–99. (open access) https://doi.org/10.1016/j.jmr.2013.09.016