Silverman P M, Baker M E, Mahony B S
J Comput Assist Tomogr. 1985 Jul-Aug;9(4):763-6.
The ability to distinguish between pleural and peritoneal fluid is important in the management of patients with peridiaphragmatic fluid collections. The differentiation of subphrenic fluid from pleural effusion by CT may be difficult and requires a detailed understanding of the normal appearance of the diaphragm on transaxial images. We report 12 patients in whom peridiaphragmatic fluid collections could potentially be misinterpreted as peritoneal rather than pleural fluid. In all cases the presence of subsegmental, basilar atelectasis with subpulmonic fluid created confusing CT images. Subsegmental atelectasis formed a curvilinear band at the lung base that simulated the hemidiaphragm. Fluid anterior to the atelectasis caused a false impression of subdiaphragmatic (peritoneal) fluid. Computed tomography through the upper abdomen excluded intraabdominal fluid in all cases. In four cases ultrasonography confirmed fluid in a supradiaphragmatic, subpulmonic location, excluded peritoneal fluid, and identified subsegmental atelectasis. The presence of subpulmonic fluid and subsegmental atelectasis requires meticulous interpretation of transaxial CT images to avoid the incorrect localization of peridiaphragmatic fluid collections.
区分胸腔积液和腹腔积液的能力对于膈周积液患者的管理至关重要。通过CT区分膈下积液和胸腔积液可能具有挑战性，需要对横断面上膈肌的正常表现有详细的了解。我们报告了12例膈周积液可能被误诊为腹腔积液而非胸腔积液的患者。在所有病例中，亚段性肺基底段肺不张合并肺下积液导致CT图像令人困惑。亚段性肺不张在肺底部形成一条曲线状带，模拟了半膈肌。肺不张前方的液体造成了膈下（腹腔）积液的假象。通过上腹部的计算机断层扫描排除了所有病例中的腹腔内积液。在4例病例中，超声检查证实了膈上、肺下位置有积液，排除了腹腔积液，并识别出亚段性肺不张。肺下积液和亚段性肺不张的存在需要对横断CT图像进行细致解读，以避免膈周积液定位错误。
