^(13)N-NH_3 PET动态显像用于垂体血流灌注和代谢功能的研究

The preliminary study of the blood perfusion and ammonia metabolism of pituitary using dynamic ^(13)N-NH_3 PET imaging

目的 用13 N NH3 PET动态显像研究正常垂体血流灌注和NH3 代谢功能。方法 2 1例受检者均无垂体相关病史 ,行13 N NH3 PET显像 ,其中 6例进行了13 N NH3 PET动态显像 ,8例同时行脑MRI检查 ,并进行MRI和PET图像融合。结果 13 N NH3 PET显像示垂体清晰显影 ,大小为 (1.0 7±0 17)cm× (1.0 9± 0 .15 )cm× (1.14± 0 .17)cm。垂体13 N NH3 标准摄取值 (SUV)为 3.84± 1.75 ,与丘脑放射性比值为 1.35± 0 .6 3。垂体动态显像均在颈内动脉显像后 10s内显影 ,13 N NH3 在垂体内明显滞留 ,2 0min内放射性无明显清除。颈内动脉显影达高峰时 ,垂体 /颈内动脉放射性比值为 0 .75±0 .13。结论 动态13 N NH3 PET显像可反映垂体血流灌注情况。垂体细胞摄取13 N NH3 ,NH3 参与垂体细胞代谢。

Objective To preliminarily study the blood perfusion and ammonia metabolism of pituitary using dynamic 13 N-NH_3 PET imaging. Methods 13 N-NH_3 PET imaging was performed on 21 subjects without pituitary diseases, 6 of them underwent dynamic PET imaging, and 8 of them underwent brain MRI in addition to PET. PET images were registered with MRI. Results The pituitary could be clearly seen in 13 N-NH_3 PET images, and being confirmed by PET/MRI image fusion. The size of pituitary was (1.07±0.17) cm×(1.09±0.15) cm×(1.14±0.17) cm, the standard uptake value (SUV) was 3.84±1.75, and the radioactivity ratio of pituitary to thalamus was 1.35±0.63. Pituitary image was seen at 10 s after the internal carotid was seen in dynamic 13 N-NH_3 PET imaging. 13 N-NH_3 was retained in pituitary, and was hardly cleaned out within 20 min. The radioactivity ratio of pituitary to internal carotid was 0.75±0.13 when the radioactivity of internal carotid was at its highest level. Conclusions The blood flow and ammonia metabolism of pituitary can be observed with dynamic 13 N-NH_3 PET imaging. Ammonia is highly extracted by pituitary, and metabolized in pituitary cells.