Magnetic resonance-thoracic ductography: imaging aid for thoracic surgery and thoracic duct depiction based on embryological considerations

Purpose. We describe the optimal protocol of magnetic resonance-thoracic ductography (MRTD) and provide examples of thoracic ducts (TD) and various anomalies. The anatomical pathway of the TD was analyzed based on embryological considerations. Methods. A total of 78 subjects, consisting of noncancer adults and patients with esophageal cancer and lung cancer, were enrolled. The MRTD protocol included a long echo time and was based on emphasizing signals from the liquid fraction and suppressing other signals, based on the principle that lymph fl ow through the TD appears hyperintense on T2-weighted images. The TD confi guration was classifi ed into nine types based on location [right and/or left side(s) of the descending aorta] and outfl ow [right and/or left venous angle(s)]. Results. MRTD was conducted in 78 patients, and the three-dimensional reconstruction was considered to provide excellent view of the TD in 69 patients, segmentalization of TD in 4, and a poor view of the TD in 5. MRTD achieved a visualization rate of 94%. Most of the patients had a right-side TD that fl owed into the left venous angle. Major confi guration variations were noted in 14% of cases. Minor anomalies, such as divergence and meandering, were frequently seen. Conclusion. MRTD allows noninvasive evaluation of TD and can be used to identify TD confi guration. Thus, this technique is considered to contribute positively to safer performance of thoracic surgery.