Studies on the clinical usefulness of the 111indium chloride bone marrow scintigraphy in patients with aplastic anemia

111Indium chloride (111In-Cl3) appears to be a radionuclide appropriate for a bone marrow scanning because of its physical and chemical characteristics; it is, like iron, bound to and transported by transferrin and it has a photopeak suitable for scintigraphy. This study was undertaken to assess the bone marrow function by 111In-Cl3 bone marrow scintigraphy in patients with asplastic anemia. Bone marrow scintigraphy was performed in 21 patients with aplastic anemia with varying degrees of severity including 15 who had no previous treatments. The scintigrams were taken 48 hours after intravenous injection of 111 MBq(3 mCi) of 111In-Cl3. All of them showed various degrees of reduction in uptake of 111In-Cl3 by the marrow. The abnormal scan grade was classified into 3 types: Type I, non-accumulation (5); Type II, low-accumulation (15); Type III, uneven accumulation (1). In type III, degree of radioisotope accumulation between the sternum and the ilium was different, and this difference correlated with that of bone marrow cellularity. In 2 patients of type II, hematological improvement occurred after treatment, which was also accompanied by simultaneous increase of 111In-Cl3 uptake by the marrow. These findings suggested that the degree of radioisotope accumulation in the marrow reflects that of bone marrow cellularity. Type I patients were clinically severe and poor in prognosis as compared to type II and type III patients; four out of 5 died within 2 months. Bone marrow transplantation may be the treatment of choice in type I patients when feasible. (author)