Diffusion tensor imaging of the median nerve: intra-, inter-reader agreement, and agreement between two software packages

Abstract

The intra-, inter-reader, and agreement between software packages for DTI measurements of the median nerve were moderate to substantial suggesting that user- and software-dependent factors contribute little to variance in DTI measurements.

Diffusion tensor imaging of the median nerve at 3.0T using different MR scanners: Agreement of FA and ADC measurements

“…We found high intra-and inter-reader agreements, reflecting high reproducibility and robustness of DTI calculations for all software solutions used in this study. This is in agreement with a recently published study where intra-and inter-reader agreement of FA and ADC measurements of the median nerve obtained with two software tools from DTI data of a single scanner were also rated moderate to substantial [15].…”

“…placement of regions-of-interest [15]. To assess the inter-vendor in relation to intra-and inter-reader variation in likely clinical scenarios, two independent readers measured all data points twice, using standard vendor-specific proprietary hardware and postprocessing software at well-defined anatomical location.…”

“…We did not use vendor independent post-processing software in order to focus on variability of FA and ADC measurements introduced by hardware and acquisition parameters only. Although, the variability of FA and ADC measurements of the median nerve was recently investigated using independent vs. vendor-specific post-processing software and shown to be moderate [15]. Last, the mean time interval between first and last MR imaging session of the wrist of a study subject was 13.8 ± 5.9 days (range, 0-20 days).…”

“…Second, as discussed above, the default settings of the DTI acquisition differed substantially between the different vendors, and not all of the parameters could be set identically. Third, we did not evaluate software differences between the different vendors since this has been published already elsewhere [15]. Fourth, 16 healthy volunteers were included.…”

“…DTI of peripheral nerves is still a relatively new technique and despite several standardization attempts [14,15], there is no agreement on the best imaging protocol with regards to both employed pulse sequence, and the chosen set of acquisition parameters [16]. In the literature, DTI studies of the median nerve have used different imaging parameters and pulse sequences: e.g., b-values ranged from 400 to 1000; number of gradient encoding diffusion directions The Philips sequence by default used single-echo preparation for single-shot echo planar imaging sequences, which resulted in shorter TEs compared to Siemens and GE with double echo preparation.…”