The dangling diaphragm sign: sensitivity and comparison with existing CT signs of blunt traumatic diaphragmatic rupture

Abstract

The objectives of our study were to describe a new CT sign of diaphragmatic injury, the "dangling diaphragm" sign, and assess its comparative utility relative to other signs in the diagnosis of diaphragmatic injury resulting from blunt trauma. CT scans of 16 blunt trauma patients (12 men and four women, mean age 36.6 years old) with surgically proven diaphragmatic injury and 32 blunt trauma patients (24 men and eight women; mean age 37.4 years old) without evidence of diaphragmatic injury at surgery were blindly reviewed by three board certified radiologists specializing in body imaging. Studies were evaluated for the presence of established signs of diaphragmatic injury, as well as the dangling diaphragm sign, in which the free edge of the torn hemidiaphragm curls inward from its normal course parallel to the body wall. The sensitivity and specificity of each sign were determined, as were the correlation between the signs and the interobserver agreement in evaluation of these findings. The radiologists' overall impression as to whether rupture was present was also recorded. In select cases, coronal and/or sagittal reformatted images were available, and they were reviewed following evaluation of the original axial images. Any change in interpretation due to these images was noted. The sensitivity of the radiologists' overall impression for detection of diaphragmatic injury was 77%, with 98% specificity. Individual signs of diaphragmatic injury had sensitivities ranging from 44% to 69%, with specificities of 98% to 100%. The dangling diaphragm sign had a sensitivity of 54% and a specificity of 98%, similar to the other signs. Multiple signs were present in most cases of diaphragmatic injury, and coronal and sagittal reformatted images had little impact. Diaphragmatic injury remains a challenging radiographic diagnosis. The dangling diaphragm is a conspicuous sign of diaphragmatic injury, and awareness of it may increase detection of diaphragmatic injury on CT studies.

Diaphragmatic injuries after blunt trauma: are they still a challenge?

“…Lastly, in the more recent studies of Nchimi et al and Dessert et al, CT analysis of the various diaphragmatic rupture signs allowed to detect a sensitivity of this technique that ranges between 77% and 100% [26][27][28]. These data show that diagnostic accuracy is improved by the enhancement of CT equipment.…”

Traumatic diaphragmatic injuries: a retrospective review of a 12-year experience at a tertiary trauma centre

“…In addition, one of these patients had normal initial CT. Our observation was consistent with the sensitivity of helical CT imaging for diagnosing diaphragmatic herniation, which has been reported to range between 56% and 87% in the literature. (20)(21)(22) CT, likewise, was limited in diagnosing diaphragmatic tears, detecting TDIs in only two out of six patients who underwent the imaging modality, so that its estimated sensitivity in our series was 33.3%.…”

Traumatic diaphragmatic injury: a review of CT signs and the difference between blunt and penetrating injury

“…Thus, it becomes imperative to be familiar with the signs of diaphragmatic rupture to avoid a missed diagnosis. Recently, Desser et al (10) have reported a new sign, called the dangling diaphragm sign, in patients with blunt diaphragmatic injuries.…”

“…The one patient in whom this sign was absent had a right-sided blunt injury and thickening of the diaphragm, although contiguous injury on either side of the diaphragm was also present. This sign has been reported to be quite sensitive (73%-82%) and specific (88%-90%) in blunt trauma (9), with the overall incidence of this sign on conventional CT being 82% (10). Although studies focusing on penetrating trauma have found this sign to have low sensitivity (36%-40%) and high specificity (90%-95%) (1, 7), we observed this sign in all six patients with penetrating trauma, indicating a frequency of 100%.…”

“…5) Dangling diaphragm sign. This sign, as observed by Desser et al (10), was considered present if the free edge of the torn diaphragm was visible as it curled inwards towards the center of the abdomen, away from or at near right angles to the chest wall. Similar to the authors (10), we considered this sign present when a comma-shaped fragment of the diaphragm was visualized along its course (Fig.…”