Cone beam computed tomography with oral contrast for accurate diagnosis and surgical planning of pharyngeal leakage and fistula: a case series

Abstract Objective: Pharyngocutaneous fistula is one of the severe complications related to head and neck surgeries. Detecting the accurate three-dimensional location of both the fistula and leakage is essential for surgical treatment. Videofluoroscopy is usually used for locating these; however, its imaging is two-dimensional. We evaluated pharyngeal leakage and fistulae using Cone Beam Computed Tomography (CBCT), known for its three-dimensional high spatial resolution imaging, taken in a sitting position, with oral contrast (contrast CBCT). Methods: Pharyngeal leakage and fistulae were evaluated in a total of 31 subjects by sequentially performing videofluoroscopy and contrast CBCT. The detection accuracy of videofluoroscopy and contrast CBCT for leakage and fistula, as well as the ability to determine the extent and depth for surgical planning, were investigated and compared. Results: Videofluoroscopy and contrast CBCT showed suspicious leakage and/or fistula in six and three of the 31 subjects, respectively. Surgical findings revealed the presence of leakage and/or fistula in three of the 31 subjects. The positive predictive values of videofluoroscopy and contrast CBCT were 50% (3/6) and 100% (3/3), respectively. Contrast CBCT provided more precise images, showing the extent and depth of leakage and fistula in three-dimensions. Conclusion: The present study’s results indicate the usefulness of contrast CBCT in terms of accurate diagnosis of leakage and fistula, due to its three-dimensional imaging being performed with the patient in a sitting position. Level of evidence: 4.

摘要
目的：咽皮肤瘘（pharyngocutaneous fistula）是头颈外科相关的严重并发症之一，精准定位瘘管及渗漏部位的三维空间位置对手术治疗至关重要。临床通常采用荧光透视（videofluoroscopy）进行病灶定位，但该检查的成像结果为二维。本研究采用具备三维高空间分辨率成像特性的锥形束计算机断层扫描（Cone Beam Computed Tomography, CBCT），配合口服对比剂（即对比CBCT），并让受试者取坐位完成扫描，以此评估咽部渗漏与瘘管情况。
方法：本研究共纳入31名受试者，依次接受荧光透视及对比CBCT检查，对其咽部渗漏与瘘管进行评估。对比分析两种检查方式对渗漏及瘘管的检测准确率，以及二者为手术规划提供病灶范围与深度信息的能力。
结果：31名受试者中，荧光透视与对比CBCT分别在6名和3名受试者中检出可疑渗漏和/或瘘管。手术探查结果显示，31名受试者中共3名存在渗漏和/或瘘管。荧光透视与对比CBCT的阳性预测值分别为50%（3/6）与100%（3/3）。对比CBCT可提供更为精准的影像，能够以三维形式展示渗漏及瘘管的范围与深度。
结论：本研究结果表明，对比CBCT可实现渗漏与瘘管的精准诊断，其优势在于可在受试者取坐位的状态下完成三维成像。
证据等级：4级。