A novel method of spleen imaging and its quantification for hypersplenism by ^99mTc-RBC SPECT/CT

Introduction: To explore the use of ^99mTc-RBC SPECT dynamic scan for spleen imaging and analyze the spleen characteristics of time-radioactivity curve(T-A curve).

Methods: In the control group, there were 1 healthy volunteer and 8 gastrointestinal bleeding patients. In the experimental group, there were 3 patients with obvious decrease of whole blood cells and splenomegaly. Pyrophosphate was intravenously injected through elbow, and after 20 mins ^99mTc other was intravenously injected through the other side, and the dynamic collection of the upper abdomen was started simultaneously. Physicians manually delineated the regions of interest in the liver and spleen of the two groups, and obtained the T-A curve of the liver and spleen. Then the curve was fitted to a straight line after 5 mins, and the α angle (between the fitted straight line and the positive half of the x-axis) was measured to realize semi-quantitative analysis.

Results: In control group the shape of T-A curve of healthy volunteers was consistent with that of gastrointestinal bleeding patients, which showed an approximate vertical rise at the beginning, and then an approximate horizontal linear, and their α angles were similar. While the T-A curve in the experimental group was continuously rising. For 2 male patients in the experimental group, they recovered obviously in the blood RT after splenectomy, while the other female patient had no operation and was still anemic during the follow-up. Conclusion: ^99mTc-labelled RBC SPECT dynamic scan realized spleen imaging and the semi-quantitative could be used for preoperative diagnosis of hypersplenism.