Diffusion Tensor Imaging of the Brachial Plexus: A Comparison between Readout-segmented and Conventional Single-shot Echo-planar Imaging

Abstract

Purpose: Diffusion tensor imaging (DTI) adds functional information to morphological magnetic resonance neurography (MRN) in the assessment of the brachial nerve plexus. To determine the most appropriate pulse sequence in scan times suited for diagnostic imaging in clinical routine, we compared image quality between simultaneous multi-slice readout-segmented (rs-DTI) and conventional single-shot (ss-DTI) echo-planar imaging techniques. Methods: Institutional Review Board (IRB) approved study including 10 healthy volunteers. The supraclavicular brachial plexus, covering the nerve roots and trunks from C5 to C7, was imaged on both sides with rs-DTI and ss-DTI. Both sequences were acquired in scan times <7 min with b -values of 900 s/mm 2 and with isotropic spatial resolution. Results: In rs-DTI image, the overall quality was significantly better and distortion artifacts were significantly lower ( P = 0.001–0.002 and P = 0.001–0.002, respectively) for both readers. In ss-DTI, a trend toward lower degree of ghosting and motion artifacts was elicited (reader 1, P = 0.121; reader 2, P = 0.264). No significant differences between the two DTI techniques were found for signal-to-noise ratios (SNR), contrast-to-noise ratios (CNR) and fractional anisotropy (FA) ( P ≥ 0.475, P ≥ 0.624, and P ≥ 0.169, respectively). Interreader agreement for all examined parameters and all sequences ranged from intraclass correlation coefficient (ICC) 0.064 to 0.905 and Kappa 0.40 to 0.851. Conclusion: Incomparable acquisition times rs-DTI showed higher image quality and less distortion artifacts than ss-DTI. The trend toward a higher degree of ghosting and motion artifacts in rs-DTI did not deteriorate image quality to a significant degree. Thus, rs-DTI should be considered for functional MRN of the brachial plexus.

Fractional anisotropy thresholding for deterministic tractography of the roots of the brachial plexus

“…Although our findings are in agreement with the metrics reported in many DTI studies of the brachial plexus 4 – 7 , 9 , 10 , 26 (Supplementary Table 2 ), our FA values are slightly lower. FA is a function of numerous factors such as the b-value and number of diffusion encoding directions 27 , 28 .…”

Diffusion tensor imaging of the roots of the brachial plexus: a systematic review and meta-analysis of normative values

“…After reviewing 27 full texts, 15 were excluded (Supplementary materials) and 9 articles (of 9 unique studies) were included [18,[21][22][23][24][25][26][27][28] (Fig. 2).…”

“…ten estimates of the FA (one from each spinal root, bilaterally) taken from the same individual will be highly correlated and without adjustment, the sample-level estimates will have falsely small variances. Seven studies [21][22][23][24][25]28] provided no information about missing data and so the risk of bias is unclear. Two studies [21,23] were judged to be at high risk of bias in the measurement of FA and MD because a bespoke region of interest was used to calculate the FA and the number of diffusion sensitising gradients used was not described [21].…”

“…Seven studies [21][22][23][24][25]28] provided no information about missing data and so the risk of bias is unclear. Two studies [21,23] were judged to be at high risk of bias in the measurement of FA and MD because a bespoke region of interest was used to calculate the FA and the number of diffusion sensitising gradients used was not described [21]. Three studies [24,25,28] were at unclear risk of bias in the measurement of FA and MD because information was lacking about preprocessing, tensorial reconstruction or how the estimates of the FA and MD were derived from images (e.g.…”

Readout-segmented diffusion tensor imaging for assessing sciatic nerve invasion by soft tissue tumor

“…Readout-segmented DTI was thus introduced by us as a new way to assess peripheral nerve, as it could provide quantitative parameters including FA and ADC. [20][21][22][23] The b = 0 map was T2 weighted. We actually found b = 0 map of rsDTI was similar to FSE T2WI image, which was valuable in assessing peripheral nerve diseases.…”