Re: “Limb Volume Changes and Activities of Daily Living: A Prospective Study” by Park et al.

Dear Editor:

We read with great interest the article entitled “Limb Volume Changes and Activities of Daily Living: A Prospective Study” by Park, et al. ¹ This study suggested that limb volume change would be positively associated with difficulty performing activities of daily living (ADLs) and it is useful for diagnosis of lymphedema.

As the author states, limb volume change might affect ADLs. However, we consider that not only lymphedema, but also limb volume has diurnal variation, and limb volume is not suitable for detecting slight changes of limbs and making early diagnosis. In the first place, imaging evaluation of lymphatic circulation is essential for diagnosis of lymphedema because lymphedema is an edematous disease caused by abnormal lymphatic circulation. Among the various lymphatic imaging examinations, indocyanine green (ICG) lymphangiography has the highest sensitivity and specificity at present.^2–5 Moreover, it is not affected by diurnal variation; therefore, we consider that ICG lymphangiography is the most useful examination for early diagnosis and evaluation of lymphedema.^2,5 The method of ICG lymphangiography is to mark the Linear pattern region immediately after the injection of ICG, and to determine the severity stage by marking the dermal backflow (DB) region in the plateau phase in 2 hours after injection of ICG. To evaluate the severity of lymphedema using ICG, we are using universal ICG lymphography stage (Table 1) that can be used for both upper and lower extremity lymphedema. In the universal ICG lymphography stage, the upper and lower limbs are divided into three regions: the upper arm/thigh, the forearm/lower leg, and the hand/foot. Severity classification ranges from stage 0 to stage V, according to visibility of the Linear pattern and differentiation and extension of DB patterns. In ICG stage 0, only Linear pattern is seen without DB pattern. In ICG stage I, Linear pattern and Splash pattern are seen. From ICG stage II through stage V, Stardust and/or Diffuse (SD) patterns are seen; in ICG stage II/III/IV, SD pattern is seen in 1/2/3 regions with Linear pattern, respectively, whereas only SD pattern is seen without Linear pattern in stage V. Splash pattern is detected the earliest (stage I), and few patients have obvious limb volume changes in this condition. However, this condition has ∼40% risk of presenting Stardust pattern and revealing edema within 2 years. When Stardust pattern is detected (stage II), edema becomes obvious in many patients, and most patients present with progressive edema. ICG lymphangiography is the most appropriate for early diagnosis of lymphedema because it can predict the prognosis of lymphedema by detecting abnormalities in lymphatic circulation at the earliest stage, when edema is not obvious and volume changes are not present.

Although ICG lymphangiography requires an invasive procedure of injection and a near-infrared camera, ICG lymphangiography is useful for the early diagnosis and evaluation of lymphedema. Consequently, we expect that ICG lymphangiography will be widely used for lymphedema screening in the future.