The thoracic duct: clinical importance, anatomic variation, imaging, and embolization.

UNLABELLED: The thoracic duct is the body's largest lymphatic conduit, draining upwards of 75 % of lymphatic fluid and extending from the cisterna chyli to the left jugulovenous angle. While a typical course has been described, it is estimated that it is present in only 40-60% of patients, often complicating already challenging interventional procedures. The lengthy course predisposes the thoracic duct to injury from a variety of iatrogenic disruptions, as well as spontaneous benign and malignant lymphatic obstructions and idiopathic causes. Disruption of the thoracic duct frequently results in chylothoraces, which subsequently cause an immunocompromised state, contribute to nutritional depletion, and impair respiratory function. Although conservative dietary treatments exist, the majority of thoracic duct disruptions require embolization in the interventional suite. This article provides a comprehensive review of the clinical importance of the thoracic duct, relevant anatomic variants, imaging, and embolization techniques for both diagnostic and interventional radiologists as well as for the general medical practitioner. KEY POINTS: • Describe clinical importance, embryologic origin, and typical course of the thoracic duct. • Depict common/lesser-known thoracic duct anatomic variants and discuss their clinical significance. • Outline the common causes of thoracic duct injury and indications for embolization. • Review the thoracic duct embolization procedure including both pedal and intranodal approaches. • Present and illustrate the success rates and complications associated with the procedure.

Thoracic duct embolization and disruption for treatment of chylous effusions: experience with 105 patients.

PURPOSE: To review the indications, technical approach, and clinical outcomes of thoracic duct embolization (TDE) and thoracic duct disruption (TDD) in patients with symptomatic chylous effusions. MATERIALS AND METHODS: A total of 105 patients who underwent 120 consecutive TDE/TDD procedures were retrospectively reviewed. Data including cause of effusion, procedural technique, and pre- and postprocedural effusion volume were analyzed. Technical and clinical success were evaluated for each procedure, with technical success defined as successful interruption of the thoracic duct by embolization or needle disruption and clinical success defined as resolution of effusion without surgical intervention. RESULTS: The technical success rate was 79% (95 of 120); 53 TDEs were performed, resulting in a 72% clinical success rate (n = 38), whereas 42 TDDs showed a 55% clinical success rate (n = 23; P = .13). Procedures to treat postpneumonectomy chylous effusions had a success rate of 82% (14 of 17), compared with 47% (nine of 19) in postpleurectomy subjects (P < .05). Clinically successful cases had lower 24-, 48-, and 72-hour postprocedural effusion volumes versus clinically unsuccessful cases (P < .05), as well as greater rates of reduction in effusion volume at these time points (P < .05). Clinical success rate in subjects with traumatic effusions was higher than in subjects with nontraumatic effusions (62% [60 of 97] vs 13% [one of eight]; P < .05), and 6.7% of subjects (n = 7) experienced minor complications. CONCLUSIONS: TDE and TDD are safe and effective minimally invasive treatments for traumatic thoracic duct injuries. In the present series, factors affecting procedural success included etiology of effusion, postprocedural effusion volume, and rate of postprocedural effusion volume reduction.

Actual Clinical Practice Assessment: A Rapid and Easy-to-Use Tool for Evaluating Cognitive Decline Equivalent to Dementia.

Background Screening tests reveal the early signs of cognitive decline, enabling better self-care and preparation for the future. We developed and evaluated the accuracy of a rapid (20 s) and easy-to-use tool called ONSEI, assessing the cognitive decline equivalent to dementia in actual clinical practice by correlating clinical diagnoses with the ONSEI classification. Methods In this retrospective observational study, data were collected from individuals who visited three neurosurgical clinics in neighboring prefectures of Tokyo, Japan. ONSEI analysis was performed using a smartphone or tablet. The tool adopts a machine-learning algorithm using the speaker's age, time-orientation task score, and acoustic features of spoken responses to that task. Significant differences in accuracy, sensitivity, and specificity were evaluated by Fisher's exact test. Results The overall classification accuracy of ONSEI was 98.1% (p<0.001). The sensitivity and specificity were 97.3% (p<0.001) and 98.5% (p<0.001), respectively. The proportion of correct classifications was consistent across different age groups. Conclusion ONSEI showed high classification accuracy for dementia in cognitively normal individuals in actual clinical practice, regardless of the facility at which the tests were conducted or the age of the participants. Thus, ONSEI can be useful for dementia screening and self-care.