Imaging of the Vasa Nervorum Using Contrast-Enhanced Ultrasound.

INTRODUCTION: We describe the use of intravenous contrast-enhanced ultrasonography to study vasa nervorum using contrast-enhanced ultrasound. METHODS: We imaged the median, femoral, or sciatic nerves in 4 patients in longitudinal plane using high-resolution ultrasound after intravenous bolus of activated Perflutren lipid microspheres. The images were acquired as photopic images (in brown color) in real time using 2-dimensional B-Flow mode scan within a selected region of interest. RESULTS: The vasa nervorum was seen as focal ovoid enhancement along either the superior and inferior aspects of the nerve most pronounced during arterial phase (peak enhancement) in all 4 patients. The fluctuating intensity of enchancement during cardiac cycle confirmed the arterial origin of enhacement. Punctate, linear, or diffuse enhancement was also seen along the trunk of the nerve. CONCLUSIONS: We were able to identify the vasa nervorum along the outer aspect of the studied nerves using contrast-enhanced ultrasound.

Corkscrew Collateral Vessels in Buerger Disease: Vasa Vasorum or Vasa Nervorum.

PURPOSE: To investigate the origin of "corkscrew" collateral vessels around the occluded popliteal artery in patients with Buerger disease by Doppler ultrasound (US) and magnetic resonance (MR) imaging in tandem with digital subtraction angiography (DSA). MATERIALS AND METHODS: Between January 2013 and June 2015, 42 patients diagnosed with Buerger disease were identified retrospectively. Patients in whom occlusion of the popliteal artery was found on DSA of the lower extremity were subjected to Doppler US and MR imaging prospectively. Fifteen of 42 patients were identified as having the required characteristics, of whom 10 participated in the present study. RESULTS: Ten patients with occlusion of the popliteal artery were selected for inclusion, and 12 lower limbs of these patients were investigated. The study cohort comprised one woman and nine men with a mean age of 41 years ± 10 (standard deviation; range, 39-58 y). Corkscrew collateral vessels identified on DSA examinations were also identified on secondary imaging (Doppler US and MR imaging) in all patients except one in whom the popliteal artery was reconstituted after short-segment occlusion. The origin of the corkscrew collateral vessels was identified as the vasa nervorum of the tibial nerve in nine patients. CONCLUSIONS: Data from the present study suggest that corkscrew collateral vessels at the knee level in patients with Buerger disease originate from the vasa nervorum of the tibial nerve rather than the vasa vasorum of the popliteal artery if the latter is occluded.