Follow-up of patients with superior vena cava syndrome by functional analysis of radionuclide venography.

In addition to imaging, radionuclide venography can be used for studying haemodynamic changes in superior vena cava syndrome (SVCS) by using the indices of transit time (TT), time of half peak count (TH) and peak count ratio (PC ratio). The objective of this study was to examine the utility of applying these indices, alongside images, in the post-therapy assessment of SVCS patients. Radionuclide venography was performed twice on 36 patients with SVCS due to thoracic malignancies, 29 of whom received specific anti-cancer therapy between the two studies (Group I); the other 7 did not receive such therapy (Group II). On the images, 12 patients in Group I showed improvement, one a deterioration and 16 no change; in Group II, 4 showed a deterioration and 3 no change. Using the indices, nearly all patients in Group I had decreased post-therapy values indicating haemodynamic improvement. A significant difference was seen between the mean (+/- S.E.) pre- and post-therapy values for TT (pre vs post: 6.2 +/- 0.7 vs 2.7 +/- 0.3 s) and TH (pre vs post: 16.9 +/- 2.3 vs 7.9 +/- 0.8 s) (P < 0.001). Although the PC ratio showed a non-significant decrement, it related to the status of collateral change. The above indices provide clinically valuable information about the haemodynamic status of patients with SVCS and can be used for their post-therapy evaluation.