Warawut Sukkasem MD, Presenter: Nothing to Disclose

Sherine George Moftah MD, Abstract Co-Author: Nothing to Disclose

Joshua O. Benditt MD, Abstract Co-Author: Nothing to Disclose

Sudhakar N. Pipavath MD, Abstract Co-Author: Research Grant, General Electric Company

J. David Godwin MD, Abstract Co-Author: Nothing to Disclose

Eric J. Stern MD, Abstract Co-Author: Nothing to Disclose

To evaluate ability of CT measurement of diaphragmatic crus thickness to distinguish a paralyzed from a non-paralyzed hemidiaphragm in patients with suspected diaphragmatic dysfunction.

We performed a retrospective review of patients with suspected diaphragmatic dysfunction between January, 1997, and February, 2013. We identified 5,402 patients, 90 (1.7%) of whom underwent chest fluoroscopy; 72 patients (1.3%) had concurrent CT scans available for measurement of diaphragmatic crus thickness at the level of celiac and superior mesenteric arteries and the L1 vertebra. ROC analysis was performed to determine an optimal threshold for discriminating between paralyzed hemidiaphragm and non-paralyzed hemidiaphragm.

Of 72 patients, 11 (15.3%) had diaphragmatic paralysis by chest fluoroscopy.  There was a significant difference in thickness of the crus for patients with and without diaphragmatic paralysis at the level of the celiac artery (mean+SD 1.7+0.6 mm vs. 3.6+1.3 mm, p = 0.017 on right; 1.1+0.4 mm vs. 3.0+1.4 mm, p = 0.001 on left) and the level of the L1 vertebra (mean+SD 1.5+0.7 mm vs. 4.4+1.6 mm, p = 0.018 on right; 1.5+0.6 mm vs. 3.6+1.7 mm, p = 0.017 on left). A threshold crus thickness of 2.5 mm at the celiac artery level on axial CT permitted optimal distinction and provided a sensitivity of 100% and a specificity of 86% in identifying diaphragmatic paralysis for the right hemidiaphragm, and a sensitivity of 100% and a specificity of 64% for the left. A threshold crus thickness of 2.5 mm at the L1 vertebra level on coronal CT permitted optimal distinction and provided a sensitivity of 100% and a specificity of 88% in identifying diaphragmatic paralysis for the right hemidiaphragm, and a sensitivity of 100% and a specificity of 77% for the left. There was no statistical difference between axial and coronal measurements (AUC 0.93 vs. 0.94, p = 1.000 on the right; 0.82 vs. 0.89, p = 0.570 on the left).  

Diaphragmatic crus atrophy assessed by CT is a good discriminator of paralyzed vs. non-paralyzed hemidiaphragm in patients with clinically suspected diaphragmatic dysfunction.

In patients with suspected hemidiaphragm paralysis, CT measurement of diaphragmatic crus thickness of <2.5 mm is a reliable finding of diaphragmatic paralysis.

Sukkasem, W, Moftah, S, Benditt, J, Pipavath, S, Godwin, J, Stern, E, Crus Atrophy: Accuracy of CT in Diagnosis of Diaphragmatic Paralysis.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13015646.html