Interpretation of lymphoscintigrams in suspected lymphoedema: contribution of delayed images.

Interpretation of lymphoscintigrams in patients with extremity oedema may be adversely affected by any variation in the acquisition protocol. The purpose of this study was to determine whether delayed (2-24 h post-injection) views provide information incremental to the first 60 min of acquisition. In a 5-year period, 31 patients (10 males, 21 females, mean age 46 years) with extremity oedema or recurrent cellulitis underwent lymphoscintigraphy using 99Tcm-antimony trisulphide colloid (99Tcm-Sb2S3). All subjects underwent an initial dynamic acquisition of the pelvis and legs for 60 min, with further images obtained after 2-24 h. Films and reports were retrospectively reviewed by an experienced observer to determine whether delayed views provided information incremental to early images. Using standard qualitative criteria, lymphoscintigrams were classified as normal (n = 12) or consistent with lymphoedema (n = 19). However, 6 of 19 (32%) patients with lymphoedema displayed normal transit of radiopharmaceutical and a normal appearance of regional lymph nodes on views acquired up to 1 h after injection; localized dermal backflow (n = 5) or lymphocoele (n = 1) were seen only on delayed images (P < 0.02). These data indicate that delayed lymphoscintigraphy images are important for the diagnosis of lymphoedema and should be obtained even when lymphatic transit of 99Tcm-Sb2S3 and lymph node appearance at 1 h are normal.