Diffusion Tensor Imaging and Tractography of Median Nerve: Normative Diffusion Values

Kabakci, Neslihan; Gürses, Bengı; Fırat, Zeynep; Bayram, Ali; Uluğ, Aziz M.; Kovanlıkaya, Arzu; Kovanlıkaya, İlhami

doi:10.2214/ajr.07.2423

Cited by 108 publications

(141 citation statements)

References 18 publications

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“…Tracking of fibers automatically started when the FA values of the voxels was above a threshold of 0.15 and was terminated at a threshold value of 0.35 or if the fiber angulation exceeded more than 55°. Similar reconstruction parameters were used in previous studies [1,6].…”

Section: Mr Imagingmentioning

confidence: 96%

“…Recently, several pilot studies with regard to the application of diffusion tensor imaging (DTI) and fiber tractography to peripheral nerves, e.g., the median, radial, and ulnar nerve at the wrist, the peroneal and tibial nerve at the knee/calf/ ankle, as well as the sciatic nerve, have been published [1][2][3][4][5][6]. Possible clinical applications include the evaluation of peripheral nerves in compressive neuropathies such as the carpal tunnel syndrome or tracking of peripheral nerves in the presence of malignant neoplasm.…”

Section: Introductionmentioning

confidence: 99%

“…Increasing b values reflect increasing diffusion weighting of a DTI acquisition [8]. In the aforementioned pilot studies, a wide range of b values (from 400 to 1,000 s/mm 2 ) were used in combination with single-shot spin-echo (ssSE)-based echo-planar imaging (EPI) pulse sequences to image structures of the peripheral nervous system [1,[3][4][5][6]. However, none of these studies clearly stated how optimal b values for imaging were chosen or determined.…”

Section: Introductionmentioning

confidence: 99%

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Diffusion tensor imaging and fiber tractography of the median nerve at 1.5T: optimization of b value

et al. 2008

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Objective The objective of this study was to systematically assess the optimal b value for diffusion tensor imaging and fiber tractography of the median nerve at 1.5 T. Materials and methods This is a prospective study which was carried out with institutional review board approval and written informed consent from the study subjects. Fifteen healthy volunteers (seven men, eight women; mean age, 31.2 years) underwent diffusion tensor imaging of the wrist. A single-shot spin-echo-based echo-planar imaging sequence (TR/TE, 7000/103 ms) was performed in each subject at eight different b values ranging from 325 to 1,550 s/mm 2 . Number and length of reconstructed fiber tracts, fiber density index (FDi), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) were calculated for the median nerve. Signal-to-noise ratio (SNR) was also calculated for each acquisition. The overall image quality was assessed by two readers in consensus by ranking representative fiber tract images for each subject using a scale range from 1 to 8 (1 = best to 8 = worst image quality). Conclusions The optimal b value for diffusion tensor imaging and fiber tractography of the median nerve at 1.5 T was 1,025 s/mm 2 .

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Section: Mr Imagingmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diffusion tensor imaging and fiber tractography of the median nerve at 1.5T: optimization of b value

et al. 2008

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“…DWI has been widely used for clinical applications in evaluation of the central nervous system for the diagnosis of diseases such as acute brain stroke [14]. Recently, it has been reported that DWI is useful for the evaluation and diagnosis of lesions such as multiple sclerosis [15,16] and peripheral nerve compression disorders such as carpal tunnel syndrome [17][18][19], using diffusion values such as ADC. An increase in the mean diffusivity (ADC) values was observed in injured nerves with demyelination [15,16,19,20].…”

Section: Introductionmentioning

confidence: 99%

“…Recently, it has been reported that DWI is useful for the evaluation and diagnosis of lesions such as multiple sclerosis [15,16] and peripheral nerve compression disorders such as carpal tunnel syndrome [17][18][19], using diffusion values such as ADC. An increase in the mean diffusivity (ADC) values was observed in injured nerves with demyelination [15,16,19,20]. Imaging of the spinal cord is challenging because of technical limitations such as the relatively small size of the cord, susceptibility artifacts because of tissue-bone interfaces, and the motion artifacts arising from respiratory activity [21].…”

Section: Introductionmentioning

confidence: 99%

Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment

et al. 2010

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Diffusion-weighted imaging (DWI) can provide valuable structural information about tissues that may be useful for clinical applications in evaluating lumbar foraminal nerve root entrapment. Our purpose was to visualize the lumbar nerve root and to analyze its morphology, and to measure its apparent diffusion coefficient (ADC) in healthy volunteers and patients with lumbar foraminal stenosis using 1.5-T magnetic resonance imaging. Fourteen patients with lumbar foraminal stenosis and 14 healthy volunteers were studied. Regions of interest were placed at the fourth and fifth lumbar root at dorsal root ganglia and distal spinal nerves (at L4 and L5) and the first sacral root and distal spinal nerve (S1) on DWI to quantify mean ADC values. The anatomic parameters of the spinal nerve roots can also be determined by neurography. In patients, mean ADC values were significantly higher in entrapped roots and distal spinal nerve than in intact ones. Neurography also showed abnormalities such as nerve indentation, swelling and running transversely in their course through the foramen. In all patients, leg pain was ameliorated after selective decompression (n = 9) or nerve block (n = 5). We demonstrated the first use of DWI and neurography of human lumbar nerves to visualize and quantitatively evaluate lumbar nerve entrapment with foraminal stenosis. We believe that DWI is a potential tool for diagnosis of lumbar nerve entrapment.

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Diffusion tensor imaging of forearm nerves in humans

Zhou

Kumaravel

Patel

et al. 2012

Magnetic Resonance Imaging

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Purpose To implement diffusion tensor imaging (DTI) protocol for visualization of peripheral nerves in human forearm. Materials and Methods This HIPAA-compliant study was approved by our institutional review board and written informed consent was obtained from 10 healthy participants. T1-and T2-weighted turbo spin echo with fat saturation, short tau inversion recovery (STIR), and DTI sequences with 21 diffusion encoding directions were implemented to acquire images of the forearm nerves with an 8 channel knee coil on a 3T MRI scanner. Identification of the nerves was based on T1-weighted, T2-weighted, STIR and DTI-derived fractional anisotropy (FA) images. Maps of the DTI derived indices, FA, mean diffusivity (MD), longitudinal diffusivity (λ//) and radial diffusivity (λ⊥) along the length of the nerves were generated. Results DTI-derived maps delineated the forearm nerves more clearly than images acquired with other sequences. Only ulnar and median nerves were clearly visualized on the DTI-derived FA maps. No significant differences were observed between the left and right forearms in any of the DTI-derived measures. Significant variation in the DTI measures was observed along the length of the nerve. Significant differences in the DTI measures were also observed between the median and ulnar nerves. Conclusion DTI is superior in visualizing the median and ulnar nerves in the human forearm. The normative data could potentially help distinguish normal from diseased nerves.

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Diffusion Tensor Imaging and Tractography of Median Nerve: Normative Diffusion Values

Abstract: The normative diffusion values of the human median nerve can be used as a reference in evaluation, diagnosis, and follow-up of entrapment, trauma, and regeneration of the median nerve.

Cited by 108 publications

References 18 publications

Diffusion tensor imaging and fiber tractography of the median nerve at 1.5T: optimization of b value

Diffusion tensor imaging and fiber tractography of the median nerve at 1.5T: optimization of b value

Clinical applications of diffusion magnetic resonance imaging of the lumbar foraminal nerve root entrapment

Diffusion tensor imaging of forearm nerves in humans

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