Following the contrast material injection, patients are imaged with MRI. High image quality of lymph nodes, central lymphatics, and flow patterns within the lymphatics has been described, but these are preliminary research experiences and are not widely available [45,46]. Computed tomography chest and abdomen Older studies noted that noncontrast computed tomography (CT) visualizes the cisterna chyli in 1.7% of cases and could differentiate this from adjacent anatomy by its low attenuation, continuity with the thoracic duct, and tubular nature [47]. At least some portion of the thoracic duct was visualized in 55% of patients in a different series [48]. Although MRI more reliably visualized more segments of the thoracic duct than CT, the addition of CT increased the number of visualized segments [36]. More recent studies with 1-mm collimation and multiplanar reformation were able to identify the thoracic duct and cisterna chyli in nearly 100% of CT scans with normal anatomy [49]. Older reports using a combination of lymphangiography and CT did not find any additional value of CT in diagnosing the lymphatic injury, although in a more recent series, a combination of CT and unilateral pedal lymphangiography was able to identify the cause and locate the leak in 75% of idiopathic chylothoraces after failure of thoracic duct ligation [30]. Moreover, in this series of 24 patients, the lack of thoracic duct leakage was managed with nonoperative therapy with higher success rates [30]. No evidence is present to suggest a role for intravenous contrast material. When the underlying etiology of chylothorax is unknown or nontraumatic, the speed, sensitivity, and specificity of CT imaging can narrow the broader differential diagnosis. Discussion of the Imaging Modalities by Variant Variant 1: Chylothorax treatment planning: traumatic etiology. Traumatic chylothoraces are a result of direct injury to thoracic lymphatics.
Chylothorax Treatment Planning. Following the contrast material injection, patients are imaged with MRI. High image quality of lymph nodes, central lymphatics, and flow patterns within the lymphatics has been described, but these are preliminary research experiences and are not widely available [45,46]. Computed tomography chest and abdomen Older studies noted that noncontrast computed tomography (CT) visualizes the cisterna chyli in 1.7% of cases and could differentiate this from adjacent anatomy by its low attenuation, continuity with the thoracic duct, and tubular nature [47]. At least some portion of the thoracic duct was visualized in 55% of patients in a different series [48]. Although MRI more reliably visualized more segments of the thoracic duct than CT, the addition of CT increased the number of visualized segments [36]. More recent studies with 1-mm collimation and multiplanar reformation were able to identify the thoracic duct and cisterna chyli in nearly 100% of CT scans with normal anatomy [49]. Older reports using a combination of lymphangiography and CT did not find any additional value of CT in diagnosing the lymphatic injury, although in a more recent series, a combination of CT and unilateral pedal lymphangiography was able to identify the cause and locate the leak in 75% of idiopathic chylothoraces after failure of thoracic duct ligation [30]. Moreover, in this series of 24 patients, the lack of thoracic duct leakage was managed with nonoperative therapy with higher success rates [30]. No evidence is present to suggest a role for intravenous contrast material. When the underlying etiology of chylothorax is unknown or nontraumatic, the speed, sensitivity, and specificity of CT imaging can narrow the broader differential diagnosis. Discussion of the Imaging Modalities by Variant Variant 1: Chylothorax treatment planning: traumatic etiology. Traumatic chylothoraces are a result of direct injury to thoracic lymphatics.