METCALF MR, ROSENTHAL RC, SELLETT LC, et al.
The scintigraphic characteristics of lymph nodes draining the ventral body wall were analyzed in 12 dogs as to their pattern of appearance and image contrast. Each dog was scanned using 99mTc-antimony sulfide colloid and 99mTc-dextran, and the imaging characteristics of these agents were compared. A large degree of variability exists in the number and pattern of lymph node appearance with either agent. No significant difference in average numbers of lymph nodes per dog was shown between agents. However, 99mTc-antimony sulfide colloid provided a significantly (p<.05) better target-to-background ratio, which determines the contrast with which lymph nodes stand out from background activity. From these findings, it is suggested that too great a variability in lymph node appearance exists using this procedure to allow a high degree of confidence in the diagnosis of metastasis to lymph nodes of the ventral body wall. However, for other purposes, 99mTc-antimony sulfide colloid is the lymphoscintigraphic agent of choice.