Comparison of Various Kinds of Probes for Lymphedematous Limbs.

Recently, there has been a growing interest in the use of lymphatic ultrasound in the preoperative investigation of lymphaticovenous anastomosis. The device used for the performance of lymphatic ultrasound varies among surgeons. In this case report, we compared several probes (18 MHz, 24 MHz, and 33 MHz linear probes) in 2 cases, to detect the lymphatic vessels in the lymphedematous limbs. In the upper limb lymphedema case, the lymphatic vessels were located at a depth of <5 mm. They could be better observed with the 33 MHz probe than with the 18 MHz probe. The probe with a high frequency (33 MHz) and high resolution seemed to be suitable for superficial layers <5 mm in depth. On the other hand, the probe of 33 MHz was not appropriate for the lymphedematous lower limb because the lymphatic vessels are usually located at around a depth of 1 cm. When comparing the 18 MHz and 24 MHz probes in observing the lymphatic vessels in the lower limb, the 24 MHz probe seemed more suitable because of its higher resolution. Among these options, the 33 MHz probe was suitable for lymphedematous upper limbs, and the 24 MHz probe was suitable for lymphedematous lower limbs.