ARRS Case of the Week- Feb 16, 2018

CHEST IMAGING: Diaphragm and Pleura

Case Author: Rachna Madan, MD Brigham Women’s Hospital

History

60-year-old woman with cervical spondylosis, recent cervical spinal surgery, and worsening dyspnea; chest radiography has been performed, and the next step must be determined.

Imaging Findings

Posteroanterior (A) and lateral (B) chest radiographs show an elevated hemidiaphragm.

Chest CT
Electromyography
Fluoroscopic sniff test
Pulmonary function testing (spirometry)
Ultrasound

Diagnosis

Fluoroscopic sniff test

Teaching Points

During a fluoroscopic sniff test, diaphragmatic movement is observed fluoroscopically while the patient sniffs forcefully. With sniffing, there is paradoxic elevation of the paralyzed side compared with rapid descent of the normal hemidiaphragm. The sniff test result is positive in more than 90% of patients with a paralyzed diaphragm. Chest CT can be performed to evaluate the course of the phrenic nerve and exclude involvement by tumor. CT findings help exclude other causes of an elevated diaphragm (diaphragmatic eventration) and diseases that mimic an elevated diaphragm (diaphragmatic rupture, peridiaphragmatic mass, and subpulmonic effusions). In the case of a mass, the contour may show focal irregularity, and the mass is not necessarily centered at the dome. Diaphragmatic hernias are usually anterior (Morgagni) or posterior (Bochdalek). Subpulmonic effusions are usually associated with blunting of the costophrenic sulcus. When diaphragmatic weakness is suspected on the basis of an elevated hemidiaphragm and dyspnea, spirometry and pulmonary function testing that includes calculation of lung volumes and maximal inspiratory and expiratory pressures is performed with the patient sitting and supine. Electromyographic and physiologic testing has a limited role in the evaluation of unilateral diaphragmatic paralysis. Diagnosis of eventration is made on the basis of the finding of localized dome-shaped elevation of the diaphragm corresponding to a weakened fibrotic area. When eventration is more diffuse, the appearance is similar to that of unilateral diaphragmatic paralysis.

Schedules and Media