Lymphoscintigraphy findings in patients with chylothorax: influence of biochemical parameters

Li Zhang; Xiaoyue Zhang; Zhe Wen; Guansheng Tong; Kun Hao; Yongkang Qiu; Lei Kang

doi:10.1186/s13550-023-01014-0

Lymphoscintigraphy findings in patients with chylothorax: influence of biochemical parameters

EJNMMI Res. 2023 Aug 3;13(1):72. doi: 10.1186/s13550-023-01014-0.

Authors

Li Zhang¹, Xiaoyue Zhang², Zhe Wen³, Guansheng Tong¹, Kun Hao⁴, Yongkang Qiu², Lei Kang⁵

Affiliations

¹ Department of Nuclear Medicine, Beijing Shijitan Hospital, Capital Medical University, No. 10 Tie Yi Rd, Haidian Dist., Beijing, 100038, China.
² Department of Nuclear Medicine, Peking University First Hospital, No. 8 Xishiku Str., Xicheng Dist., Beijing, 100034, China.
³ Department of Nuclear Medicine, Beijing Shijitan Hospital, Capital Medical University, No. 10 Tie Yi Rd, Haidian Dist., Beijing, 100038, China. wenzhe2306@bjsjth.cn.
⁴ Department of Lymphatic Surgery, Beijing Shijitan Hospital, Capital Medical University, Beijing, 100038, China.
⁵ Department of Nuclear Medicine, Peking University First Hospital, No. 8 Xishiku Str., Xicheng Dist., Beijing, 100034, China. kanglei@bjmu.edu.cn.

Abstract

Background: Chylothorax is a condition that can be challenging to diagnose due to its nonspecific clinical presentation. Several biochemical parameters of chylous pleural effusion have been identified as important indicators for the diagnosis of chylothorax. Lymphoscintigraphy is utilized to assess chylothorax and determine the location of chyle leakage. The present study aimed to evaluate the correlation between the biochemical parameters of chylous pleural effusion and ^99mTc-dextran (^99mTc-DX) lymphoscintigraphy in diagnosing chylothorax.

Material and methods: A total of 120 patients were enrolled in the study, 83 of the patients with unilateral chylothorax, and 37 with bilateral chylothorax. All patients underwent both ^99mTc-DX lymphoscintigraphy and pleural effusion laboratory analysis. The ^99mTc-DX lymphoscintigraphy images were categorized as positive or negative groups based on the presence or absence of abnormal radioactive tracer accumulation in the thorax, respectively. The biochemical parameters of the two groups were subsequently compared.

Results: Among these patients, 101 (84.17%) had exudative effusions, while 19 (15.83%) had transudative effusions, as determined by the levels of pleural effusion protein, lactate dehydrogenase and cholesterol. Abnormal tracer accumulation in thorax was observed in 82 patients (68.33%). Our findings indicated that lymphoscintigraphy results were not associated with exudative and transudative chylothorax (P = 0.597). The lymphoscintigraphy positive group displayed significantly higher levels of pleural effusion triglyceride and pleural effusion triglyceride/serum triglyceride ratio in all biochemical parameters, compared to the negative group (P = 0.000 and P = 0.005). We identified cutoff values of 2.870 mmol/L for pleural effusion triglycerides and 4.625 for pleural effusion triglyceride/serum triglyceride ratio, respectively, which can facilitate differentiating the positive and negative cases on lymphoscintigraphy.

Conclusion: Lymphoscintigraphy technique is a dependable diagnostic tool for the qualitative assessment of chylous pleural effusion. Higher pleural effusion triglyceride level and pleural effusion triglyceride/serum triglyceride ratio indicate a positive result in patients with chylothorax on lymphoscintigraphy, with the cutoff values of 2.870 mmol/L and 4.625 aiding in the diagnosis.

Keywords: Cholesterol; Chylothorax; Lactate dehydrogenase; Lymphoscintigraphy; Triglyceride.