4.7-T diffusion tensor imaging of acute traumatic peripheral nerve injury.
Diagnosis and management of peripheral nerve injury is complicated by the inability to assess microstructural features of injured nerve fibers via clinical examination and electrophysiology. Diffusion tensor imaging (DTI) has been shown to accurately detect nerve injury and regeneration in crush models of peripheral nerve injury, but no prior studies have been conducted on nerve transection, a surgical emergency that can lead to permanent weakness or paralysis. Acute sciatic nerve injuries were performed microsurgically to produce multiple grades of nerve transection in rats that were harvested 1 hour after surgery. High-resolution diffusion tensor images from ex vivo sciatic nerves were obtained using diffusion-weighted spin-echo acquisitions at 4.7 T. Fractional anisotropy was significantly reduced at the injury sites of transected rats compared with sham rats. Additionally, minor eigenvalues and radial diffusivity were profoundly elevated at all injury sites and were negatively correlated to the degree of injury. Diffusion tensor tractography showed discontinuities at all injury sites and significantly reduced continuous tract counts. These findings demonstrate that high-resolution DTI is a promising tool for acute diagnosis and grading of traumatic peripheral nerve injuries.
Departments of 1 Biomedical Engineering and.|Plastic Surgery, Vanderbilt University Medical Center;
Richard B
RB
Boyer
Departments of 1 Biomedical Engineering and.|Vanderbilt University Institute of Imaging Science, Nashville, Tennessee; and.
Nathaniel D
ND
Kelm
Plastic Surgery, Vanderbilt University Medical Center;
D Colton
DC
Riley
Plastic Surgery, Vanderbilt University Medical Center;|Department of Surgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas.
Kevin W
KW
Sexton
Plastic Surgery, Vanderbilt University Medical Center;
Alonda C
AC
Pollins
Plastic Surgery, Vanderbilt University Medical Center;
R Bruce
RB
Shack
Departments of 1 Biomedical Engineering and.|Vanderbilt University Institute of Imaging Science, Nashville, Tennessee; and.
Richard D
RD
Dortch
Plastic Surgery, Vanderbilt University Medical Center;
Lillian B
LB
Nanney
Departments of 1 Biomedical Engineering and.|Vanderbilt University Institute of Imaging Science, Nashville, Tennessee; and.
Mark D
MD
Does
Departments of 1 Biomedical Engineering and.|Plastic Surgery, Vanderbilt University Medical Center;
Wesley P
WP
Thayer
D000208:Acute Disease; D000818:Animals; D016880:Anisotropy; D056324:Diffusion Tensor Imaging; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D035002:Lower Extremity / Q000473:pathology; D008297:Male; D059348:Peripheral Nerve Injuries / Q000175:diagnosis*; D012372:ROC Curve; D017207:Rats, Sprague-Dawley; D020426:Sciatic Neuropathy / Q000175:diagnosis; D012680:Sensitivity and Specificity; D013223:Statistics as Topic
AUC = area under the curve; DTI = diffusion tensor imaging; DTPA = diethylene triamine pentaacetic acid; FA = fractional anisotropy; MD = mean diffusivity; MRI; MRN = MR neurography; PBS = phosphate-buffered saline; PFA = paraformaldehyde; ROC = receiver-operator characteristic; ROI = region of interest; SNR = signal-to-noise ratio; diffusion tensor imaging; diffusion tensor tractography; nerve transection; neurography; neurotmesis; peripheral nerve injury; λ‖ = axial diffusivity; λ⊥ = radial diffusivity