Assessment of leg oedema by dynamic lymphoscintigraphy with intradermal injection of technetium-99m human serum albumin and load produced by standing

Abstract

This study was a preliminary evaluation of the utility of dynamic lymphoscintigraphy with technetium-99m human serum albumin (HSA) and a load produced by standing in the assessment of lymphatic dysfunction in patients with leg oedema. The 71 subjects investigated included 53 patients with lymphoedema, six with venous occlusion alone and five with lymphovenous occlusion, as well as seven normal subjects. After intradermal injection of 99mTc-HSA into an interdigital space in each foot, dynamic scintigrams were recorded with the patient supine for 15 min. The subjects then stood in place and images were recorded for an additional 15 min. Relative changes in lymphatic tracer transport before and after standing were analysed on time-activity curves (TACs). This test was compared with a conventional test in a supine position in six patients with lymphoedema, and was repeated in five other patients with lymphoedema. It was found that in the normal limbs, a standing load activated tracer transport to the draining lymphatic vessels, resulting in a rapid stepwise increase in tracer activity, large spiking waves and a decreasing phase following a peak in tracer activity on TACs. In 59 lymphoedematous limbs, including some with a mild form of oedema without morphological abnormalities on scintigrams, this load failed to induce a sufficient activation of tracer transport, and the frequencies of each of the three normally appearing changes described above significantly decreased compared with those in the 14 normal limbs (P < 0.0001, P < 0.01 and P < 0.0001, respectively). In addition, there were significant reductions in the relative increases in maximum activity and clearance times after standing (both P < 0.0001). These abnormalities significantly correlated with the grade of severity of oedema. Six limbs with lymphovenous occlusion showed significant reductions in tracer transport compared to six limbs with venous occlusion. Lymphatic dysfunction was accentuated more by this test than by the conventional test, and repeated tests showed consistent results in the same individuals. It is concluded that under a standardized load, this quick test seems of value in providing a sensitive and objective assessment of lymphatic dysfunction in the lower limbs, and is also advantageous for image interpretation since accelerated tracer transport clearly visualizes compromised lymphatics. This test may also be helpful in distinguishing purely venous oedema from mixed lymphovenous disease.

MR lymphangiography at 3.0 tesla to assess the function of inguinal lymph node in low extremity lymphedema

“…In this study, abnormal lymphatic vessels were observed in low extremity lymphedema patients. Moreover, dermal backflow and honeycomb‐like network was observed in some patients, which may be due to opacification of multiple tiny peripheral lymphatic vessels or due to extravasation of the contrast agent . The morphologic changes of the LV in this study were consistent with other reports .…”

Dynamic lymph flow imaging in patients with oedema of the lower limb for evaluation of the functional outcome after autologous lymph vessel transplantation: an 8-year follow-up study

“…Using lymphoscintigraphy, the diagnosis of lymphatic dysfunction is based on abnormal radiotracer distribution and/or delayed or absent lymphatic flow [8,9]. Lymphoscintigraphy permits the detection of retarded tracer transport even in mild lymphoedema without morphological abnormalities [9] because impaired lymphatic function is visualised before morphological changes appear [10]. Therefore it lends itself more readily to repeated studies for follow-up than other available tests [11].…”

“…The cross-over filling of the contralateral pelvic lymph nodes proves the patency of the graft the diagnostic modality of choice for the assessment of functional disturbances of lymphatic vessels [8]. Using lymphoscintigraphy, the diagnosis of lymphatic dysfunction is based on abnormal radiotracer distribution and/or delayed or absent lymphatic flow [8,9]. Lymphoscintigraphy permits the detection of retarded tracer transport even in mild lymphoedema without morphological abnormalities [9] because impaired lymphatic function is visualised before morphological changes appear [10].…”

“…Furthermore the uptake of particulate contrast agents into initial lymphatics also depends on the anatomical injection site [14,15,16]. Asymmetrical injection of tracer and dilution of tracer activity in oedematous legs would greatly influence the absolute values [9]. The combination of a semiquantitative index of lymphatic transport and visual evaluation of the lymphoscintigraphy image pattern reliably depicts abnormalities in the lymphatic circulation [8].…”

“…Lymph flow may be simultaneously disturbed by damage or fragmentation of dermal lymphatic networks associated with recurrent phlebitis, and by compression of lymphatics by increased interstitial fluid and cutaneous thickening [8]. Furthermore, the intrinsic lymphatic pump activity may deteriorate because of lymphatic fibrosis or valvular incompetence [9,17,18]. This might explain why there were no significant changes in the clinically observed postoperative volume of the treated limb.…”