Comprehensive Imaging Review of Pleural Fistulas from Diagnosis to Management.

Pleural fistula is an abnormal communication between the pleural cavity and an adjacent structure. The interplay of anatomic and physiologic factors including proximity to various intrathoracic structures, deep pleural recesses, and negative pleural pressures makes the pleura an easy victim of fistulization. Iatrogenic creation followed by necrotizing infections and malignancies are the most common causes. While the overall incidence and size of postsurgical pleural fistulas are decreasing with increased adoption of vascularized flaps for high-risk resections, the smaller fistulas that develop in the setting of post-radiation therapy changes, with necrotizing infections in immunosuppressed patients, and with use of newer antiangiogenic chemotherapies can be challenging to visualize directly. Imaging signs in clinical practice are often subtle and indirect. Multimodality imaging and biochemical pleural fluid analysis can offer important adjunctive information when a diagnosis is only suggested with the first imaging study. Certain pleural fistulas are inconsequential, some spontaneously close with or without diversion of flow or use of positive-pressure ventilation, while others carry a higher risk of complications or recurrence. Estimated fistula size, factors that impair healing, and the possibility of diversion are important considerations when deciding between endoscopic or surgical closure. The authors have tailored this article for a general imager or clinical practitioner and review 10 types of pleural fistulas, ranging from routine to rare, with regard to their etiology, pathophysiology, clinical cues, imaging features, nuances of pleural fluid analysis, and management options available today. ©RSNA, 2022.