Imaging of the Vasa Nervorum Using Contrast-Enhanced Ultrasound

Contrast-enhanced ultrasonography for evaluation of the blood perfusion of sciatic nerves in healthy dogs

Blood supply to the peripheral nerves is essential for fulfilling their structural and functional requirements. This prospective, experimental, exploratory study aimed to assess the feasibility of contrast-enhanced ultrasonography (CEUS) for evaluating blood perfusion of the sciatic nerve in normal dogs. Contrast-enhanced ultrasonography examinations were performed on the bilateral sciatic nerves after bolus injection of Sonazoid™ (0.015 mL/kg) in 12 healthy Beagles for 150 s. Then, qualitative assessment of the wash-in timing, degree and enhancement patterns, and quantitative measurement of the peak intensity and time to peak intensity were performed from the sciatic nerve. The results were compared to those obtained from the adductor muscle around the nerve and caudal gluteal artery. After contrast agent injection, the sciatic nerve was enhanced at approximately 13-14 s, immediately after wash-in of the caudal gluteal artery. The peak intensity of the sciatic nerve was significantly lower than that of the caudal gluteal artery and higher than that of the adductor muscle. The time to peak intensity was significantly slower than that of the caudal gluteal artery; but was not significantly different from that of the adductor muscle. There were no significant differences in the peak intensity and time to peak intensity between the left and right sciatic nerves. These results demonstrate the feasibility of CEUS to assess blood perfusion of the sciatic nerve in healthy dogs qualitatively and quantitatively. This result from healthy dogs could serve as a reference for further studies that evaluate the sciatic nerve under pathological conditions.

Evaluation of the Crushed Sciatic Nerve and Denervated Muscle with Multimodality Ultrasound Techniques: An Animal Study

This study was aimed at evaluating the value of multimodality ultrasound techniques in the detection of crushed sciatic nerve and denervated muscle in rabbits. Fifty healthy male New Zealand white rabbits were randomly divided into five groups (n = 10 in each group): four crushed injury groups at 1, 2, 4 and 8 wk post-sciatic nerve crushed injury, and a control group without crush injury. The crushed sciatic nerve and denervated muscle were measured with conventional ultrasound, shear wave elastography and contrast-enhanced ultrasonography, and the results were compared with the histopathological parameters. The inter- and intra-reader reliability of multimodality ultrasound was assessed with intra-class correlation coefficients. Our results revealed that the sciatic nerve thickened at 2 wk post-crushed injury (p < 0.01), but recovered to almost normal thickness at 8 wk post-injury. Stiffness of the crushed nerve gradually increased (p < 0.01), and intraneural blood volume decreased (area under the curve, peak intensity, time to peak, p < 0.01 each) over time. Histopathological evaluation revealed obvious collagen hyperplasia and poor regenerated microvascular and sparse axonal regeneration and remyelination. Compared with that of the control group, the elastic modulus of the denervated muscle significantly increased (p < 0.05), which may be related to the increased intramuscular collagen (p < 0.01) and decreased muscle fiber cross-sectional area (p < 0.01). There were no significant differences in contrast-enhanced ultrasonography parameters (area under the curve, peak intensity, time to peak) of the denervated muscle between the crush injury groups and the control group (p >0.05). All ultrasound results had excellent inter- and intra-reader consistency (intraclass correlation coefficient >0.80). In conclusion, multimodality ultrasound techniques could provide quantitative information on the morphologic changes, mechanical properties and blood perfusion of crushed nerve and denervated muscle, which may be of great importance in clinical practice.

Neural gliding and neural tensioning differently impact flexibility, heat and pressure pain thresholds in asymptomatic subjects: A randomized, parallel and double-blind study

OBJECTIVE

To compare the effect of neural gliding and tensioning on hamstring flexibility, nerve function (heat and cold thresholds) and pain sensitivity (pain intensity and pressure pain threshold) of the mobilized and non-mobilized lower limbs at post-intervention and 24 h follow up.

DESIGN

Randomized, parallel and double blinded trial.

SETTING/PARTICIPANTS

Forty-eight asymptomatic participants.

INTERVENTION(S)

Participants received neural gliding (n = 23) or tensioning (n = 25). Main Outcome Measures - Straight leg raising (SLR; in degrees), heat and cold threshold (ºC), pressure pain threshold (PPT; in Kgf) and pain intensity (visual analogue scale), taken at baseline, post-intervention and at 24 h follow up.

RESULTS

There was a significant interaction between time, intervention and limb for SLR (F2,45 = 3.83; p = 0.029). A significant interaction between time and intervention for PPT (F2,45 = 3.59; p = 0.036) and heat threshold (F2,45 = 5.10; p = 0.01). A significant effect of time (F2,45 = 9.42; p < 0.001) and of limb (F1,46 = 4.78; p = 0.035) for pain intensity during SLR, and a significant effect of time (F2,45 = 3.65; p = 0.034) for pain intensity during PPT.

CONCLUSION

Gliding and tensioning had similar and positive effects for flexibility in the mobilized limb, but tensioning was superior for the non-mobilized limb. Gliding was superior to tensioning for pressure pain and heat thresholds.