Reliability of peripheral intraneural microhemodynamics evaluation by using contrast-enhanced ultrasonography

Abstract

High intra-observer, inter-observer, and inter-examination reproducibility of CEUS was obtained in the evaluation of the intraneural enhancement pattern when the region of interest was placed in the proximal region of the median nerve.

Blood Flow Changes in Subsynovial Connective Tissue on Contrast‐Enhanced Ultrasonography in Patients With Carpal Tunnel Syndrome Before and After Surgical Decompression

“…Normalized data were obtained for each wrist relative to the baseline value by using the average from the first approximately 18 seconds. The high reproducibility of CEUS confirmed by previous data allowed us to examine the blood flow proximal to the carpal tunnel in patients with CTS …”

“…Although blood flow within the median nerve has been evaluated by color Doppler US in patients with CTS, it is difficult to detect low‐volume blood flow in the subsynovial connective tissue by using conventional methods. Although Evans et al reported reliable and valid techniques using CEUS for measuring vascularity associated with nerve disorders in animal models, we have recently demonstrated the high reproducibility of CEUS of the microcirculation in humans; in this study, we evaluated the blood flow in the subsynovial connective tissue proximal to the carpal tunnel for the first time.…”

“…Sonograms were collected on a US unit (Aplio 500, Toshiba Medical Systems Corp, Tochigi, Japan) with an 8.0‐MHz center frequency (bandwidth, 5–12 MHz) linear transducer (PLT‐805AT), and contrast harmonic imaging (referred to commercially as advanced pulse subtraction) with a reception frequency of 5.5 MHz was used. The mechanical index was set at 0.25 to 0.26 as previously reported . Before the CEUS examination, the cross‐sectional area was calculated on B‐mode images as previously reported .…”

“…[8][9][10] A recent study showed that contrast-enhanced ultrasonography (CEUS) had high reproducibility for evaluation of intraneural blood flow in the median nerve proximal to the carpal tunnel. 11 Another study using CEUS revealed that the intraneural blood flow in patients with of CTS was significantly higher than that in asymptomatic volunteers. 12 We hypothesized that the blood flow within the subsynovial connective tissue would differ between healthy persons and patients with CTS, and in addition, that there would be differences between the microcirculation in the subsynovial connective tissue before and after carpal tunnel release.…”

“…The improvement in the image resolution of US obtained by using microbubble‐based contrast agents has made it possible to obtain high‐resolution images even of low‐volume, slow blood flow in connective tissue . A recent study showed that contrast‐enhanced ultrasonography (CEUS) had high reproducibility for evaluation of intraneural blood flow in the median nerve proximal to the carpal tunnel . Another study using CEUS revealed that the intraneural blood flow in patients with of CTS was significantly higher than that in asymptomatic volunteers …”