Nineteen bone marrow transplant (BMT) patients were studied prospectively with serial 99Tcm-sulphur colloid liver/spleen scintigraphy to determine if quantification of lung uptake aided in early identification of hepatic veno-occlusive disease (VOD). Anterior lung/liver (L/L) and geometric mean spleen/liver (S/L) ratios were determined prior to BMT conditioning chemotherapy/total body irradiation, and at 1-4 days (n = 17), 11-14 days (n = 18) and 27-33 days (n = 15) post-BMT, and correlated with the presence of VOD post-BMT employing standard clinical criteria. Veno-occlusive disease developed in nine patients (47%): mild 5; moderate 1; severe 3. Of 17 patients studied 1-4 days post-BMT, at which time no patient had objective evidence of VOD, an L/L ratio > or = 0.075 predicted subsequent development of moderate or severe VOD with a sensitivity of 100% (4/4) and a specificity of 85% (11/13). An L/L ratio > or = 0.075 on any post-BMT study had a sensitivity of 100% (9/9) and specificity of 70% (7/10) for the diagnosis of VOD of any severity. Increase in lung uptake at 4 weeks post-BMT was associated with a poor prognosis in patients with VOD, as the four with L/L ratios of 0.085-0.115 died during the first year, while the two patients with L/L ratios of 0.032 and 0.078 survived. Increased lung uptake on liver/spleen scintigraphy early post-BMT may be useful for identifying patients likely to develop significant VOD and for assessing their prognosis.