An optimal acquisition and post-processing pipeline for hybrid IVIM-DKI in head and neck.
PURPOSE
To optimize the diffusion-weighting b values and postprocessing pipeline for hybrid intravoxel incoherent motion diffusion kurtosis imaging in the head and neck region.


METHODS
Optimized diffusion-weighting b value sets ranging between 5 and 30 b values were constructed by optimizing the Cramér-Rao lower bound of the hybrid intravoxel incoherent motion diffusion kurtosis imaging model. With this model, the perfusion fraction, pseudodiffusion coefficient, diffusion coefficient, and kurtosis were estimated. Sixteen volunteers were scanned with a reference b value set and 3 repeats of the optimized sets, of which 1 with volunteers swallowing on purpose. The effects of (1) b value optimization and number of b values, (2) registration type (none vs. intervolume vs. intra- and intervolume registration), and (3) manual swallowing artifact rejection on the parameter precision were assessed.


RESULTS
The SD was higher in the reference set for perfusion fraction, diffusion coefficient, and kurtosis by a factor of 1.7, 1.5, and 2.3 compared to the optimized set, respectively. A smaller SD (factor 0.7) was seen in pseudodiffusion coefficient. The sets containing 15, 20, and 30 b values had comparable repeatability in all parameters, except pseudodiffusion coefficient, for which set size 30 was worse. Equal repeatability for the registration approaches was seen in all parameters of interest. Swallowing artifact rejection removed the bias when present.


CONCLUSION
To achieve optimal hybrid intravoxel incoherent motion diffusion kurtosis imaging in the head and neck region, b value optimization and swallowing artifact image rejection are beneficial. The optimized set of 15 b values yielded the optimal protocol efficiency, with a precision comparable to larger b value sets and a 50% reduction in scan time.
['Sijtsema|Nienke D|ND|0000-0001-7928-1578', 'Petit|Steven F|SF|', 'Poot|Dirk H J|DHJ|0000-0003-0656-2963', 'Verduijn|Gerda M|GM|', 'van der Lugt|Aad|A|', 'Hoogeman|Mischa S|MS|', 'Hernandez-Tamames|Juan A|JA|']
D016477:Artifacts D038524:Diffusion Magnetic Resonance Imaging D056324:Diffusion Tensor Imaging D006801:Humans D009038:Motion D015203:Reproducibility of Results
head and neck bvalue optimization diffusion-weighted imaging (DWI) intravoxel incoherent motion diffusion kurtosis imaging (IVIM-DKI) non-Gaussian IVIM (NG-IVIM) swallowing artifact correction