Thickening of the diaphragm: a new computed tomography sign of diaphragm injury

The breadth of the diaphragm: updates in embryogenesis and role of imaging

The diaphragm is an unique skeletal muscle separating the thoracic and abdominal cavities with a primary function of enabling respiration. When abnormal, whether by congenital or acquired means, the consequences for patients can be severe. Abnormalities that affect the diaphragm are often first detected on chest radiographs as an alteration in position or shape. Cross-sectional imaging studies, primarily CT and occasionally MRI, can depict structural defects, intrinsic and adjacent pathology in greater detail. Fluoroscopy is the primary radiologic means of evaluating diaphragmatic motion, though MRI and ultrasound also are capable of this function. This review provides an update on diaphragm embryogenesis and discusses current imaging of various abnormalities, including the emerging role of three-dimensional printing in planning surgical repair of diaphragmatic derangements.

Evaluation of the multi-slice computed tomography outcomes in diaphragmatic injuries related to penetrating and blunt trauma

PURPOSE

Traumatic diaphragmatic rupture is a diagnostic challenge for both surgeons and radiologists and generally occurs secondary to blunt and penetrating trauma of thoracoabdominal region.

MATERIAL AND METHODS

56 patients who underwent surgical procedure due to blunt or penetrating trauma were included to the study.

RESULTS

There were 37 diaphragmatic ruptures in the left side and 19 patients in the right side. The most common radiological finding was "the direct monitoring of defect" (54,3%).

CONCLUSION

Findings suggestive of diaphragmatic rupture must be carefully evaluated in patients with blunt or penetrating thoracoabdominal trauma.

Validity and reliability of fluoroscopy for digital radiography: a new way to evaluate diaphragmatic mobility

Background

Fluoroscopy is considered the most accurate method to evaluate the diaphragm, yet most existing methods for measuring diaphragmatic mobility using fluoroscopy are complex. To assess the validity and reliability of a new evaluation method of diaphragmatic motion using fluoroscopy by digital radiography of healthy adults.

Methods

Twenty-six adults were evaluated, according to the parameters: anthropometry and pulmonary function test. The evaluation of diaphragm mobility by means of fluoroscopy by digital radiography method was randomly conducted by two raters (A and B). The Pearson correlation coefficient and the intraclass correlation coefficient (ICC) were used to assess the concurrent validity. The inter-rater and intra-rater reliability of the measurement of diaphragmatic motion was determined using ICC and a confidence interval of 95%.

Results

There was a relationship in the assessment of the concurrent validity. There was good inter-rater reliability for right hemidiaphragm mobility and moderate reliability for left hemidiaphragm in the first assessment. In the second assessment, there was good reliability for the mobility of both hemidiaphragms. There was good intra-rater reliability in the mobility of both hemidiaphragms for raters A and B.

Conclusion

The evaluation of diaphragmatic motion using fluoroscopy by digital radiography proved to be a valid and reliable method of healthy adults.

Imaging of Traumatic Diaphragmatic Rupture: Evaluation of Diagnostic Accuracy at a Level 1 Trauma Centre

Purpose

Traumatic diaphragmatic rupture (TDR) is an uncommon injury that can be associated with significant morbidity if not detected and treated in a timely manner. The purpose of our study was to evaluate the diagnostic accuracy of 64-slice multidetector computed tomography (64-MDCT) for the detection of TDR in patients at our level 1 trauma centre.

Methods

We used our hospital's trauma registry to identify patients with a diagnosis of TDR from January 1, 2008, to December 31, 2012. Only patients with a 64-MDCT scan at presentation who subsequently underwent laparotomy/laparoscopy were included in the study cohort. Using surgical findings as the gold standard, the accuracy of the prospective radiology reports was analyzed.

Results

Of the 3225 trauma patients who presented to our institution, 38 (1.2%) had a TDR. Fourteen of the 38 were excluded as they did not have MDCT before surgery. The study cohort consisted of 20 males and 4 females with a median age of 34.5 years and a median Injury Severity Score (ISS90) of 26. Fifteen had blunt trauma while 9 had a penetrating injury. The overall sensitivity of the radiology reports was 66.7% (95% confidence interval [CI]: 46.7%-82.0%), specificity was 100% (95% CI: 94.1%-100%), positive predictive value was 100% (95% CI: 80.6%-100%), negative predictive value was 88.4% (95% CI: 78.8%-94.0%), and accuracy was 90.6% (95% CI: 82.5%-95.2%). However, only 3 of 9 patients with penetrating injury had a correct preoperative diagnosis. Two of the 6 missed penetrating trauma cases had only indirect signs of injury.

Conclusions

The detection of TDR in trauma patients on 64-MDCT can be improved, especially in patients presenting with penetrating injury. A careful search for subtle diaphragmatic defects and indirect evidence of injury is important to avoid missing the diagnosis.

Penetrating Thoracic Injury

This article discusses the role of radiology in evaluating patients with penetrating injuries to the chest. Penetrating injuries to the chest encompass ballistic and nonballistic injuries and can involve superficial soft tissues of the chest wall, lungs and pleura, diaphragm, and mediastinum. The mechanism of injury in ballistic and nonballistic trauma and the impact the injury trajectory has on imaging evaluation of penetrating injuries to the chest are discussed. The article presents the broad spectrum of imaging findings a radiologist encounters with penetrating injuries to the chest, with emphasis on injuries to the lungs and pleura, diaphragm, and mediastinum.

CT of blunt diaphragmatic rupture

The diagnosis of blunt diaphragmatic rupture (BDR) is difficult and often missed, leaving many patients with this traumatic injury at risk for life-threatening complications. The potential diagnostic pitfalls are numerous and include anatomic variants and congenital and acquired abnormalities. Chest radiography, despite its known limitations, may still be helpful in the early assessment of severe thoracoabdominal trauma and for detecting initially overlooked BDR or late complications of BDR. However, since the development of helical and multidetector scanners, computed tomography (CT) has become the reference standard; thus, knowledge of the CT signs suggestive of BDR is important for recognition of this injury pattern. A large number of CT signs of BDR have been described elsewhere, many of them individually, but the use of various appellations for the same sign can make previously published reports confusing. The systematic description and classification of CT signs provided in this article may help clarify matters and provide clues for diagnosing BDR. The authors describe 19 distinct CT signs grouped in three categories: direct signs of rupture, indirect signs that are consequences of rupture, and signs that are of uncertain origin. Since no single CT sign can be considered a marker leading to a correct diagnosis in every case of BDR, accurate diagnosis depends on the analysis of all signs present.

Diaphragmatic injuries after blunt trauma: are they still a challenge? Reviewing CT findings and integrated imaging

Traumatic diaphragmatic rupture is a life-threatening injury that may occur in patients with blunt trauma. At present, supine chest radiographs is the initial, most commonly performed imaging test to evaluate a traumatic injury of the thorax. However, computed tomography (CT) is the imaging tool of choice, as it is the 'gold standard' for the detection of diaphragmatic injury after trauma. In particular, recent literature indicates that multidetector CT with multiplanar reformations has significantly improved in accuracy. Radiologists working in the emergency room should keep in mind the possibility of diaphragmatic injuries and should routinely integrate the axial images CT with multiplanar reformations in order to detect any potential, subtle or doubtful sign of incomplete diaphragmatic injury.

Computed tomography in left-sided and right-sided blunt diaphragmatic rupture: experience with 43 patients

AIM

To investigate differences in the radiographic signs for left and right-sided blunt diaphragmatic rupture (BDR) in order to provide guidance to avoid missing these injuries.

MATERIALS AND METHODS

A retrospective review of the computed tomography (CT) examinations of 43 patients with BDR treated at our hospital between January 1995 and 2007 was undertaken. The presence of diaphragmatic discontinuity, diaphragmatic thickening, herniation of abdominal organs into the thoracic cavity, collar/hump sign, dependent viscera sign, abnormally elevated 4 cm or more above the dome of the other-sided hemi-diaphragm, and of associated injuries was recorded and their relationship to each other and to BDR diagnosis examined. A comparison between the use of axial and sagittal/coronal reconstruction images in diagnosis was also performed in 15 patients.

RESULTS

On axial imaging, left-sided diaphragmatic rupture occurred in 31 patients (72%) and right-sided in 12 (28%). Twenty-nine patients had associated injuries. More than 60% of the patients showed the "dependent viscera" sign, "abdominal organ herniation" sign, diaphragm thickening, or had a more than 4 cm elevation of one side of the diaphragm. "Diaphragmatic discontinuity" and "stomach herniation" were seen almost exclusively in left-sided rupture. Those with BDR and haemothorax had a significantly lower incidence of "diaphragm discontinuity" (p=0.034) than those without haemothorax. Sagittal/coronal reconstruction slightly increased the number of band signs, diaphragmatic discontinuities and diaphragmatic thickenings seen.

CONCLUSIONS

Of the CT signs examined in this study, when herniation of abdominal organs was used as a diagnostic marker, only a very small fraction of trauma patients identifiable by CT would be missed. Further, CT signs differ for left-sided and right-sided BDR, thus the possibility of BDR should be considered when any of the reported CT signs are present.

MDCT diagnosis of penetrating diaphragm injury

The purpose of the study was to determine the diagnostic sensitivity and specificity of multidetector CT (MDCT) in detection of diaphragmatic injury following penetrating trauma. Chest and abdominal CT examinations performed preoperatively in 136 patients after penetrating trauma to the torso with injury trajectory in close proximity to the diaphragm were reviewed by radiologists unaware of surgical findings. Signs associated with diaphragmatic injuries in penetrating trauma were noted. These signs were correlated with surgical diagnoses, and their sensitivity and specificity in assisting the diagnosis were calculated. CT confirmed diaphragmatic injury in 41 of 47 injuries (sensitivity, 87.2%), and an intact diaphragm in 71 of 98 patients (specificity, 72.4%). The overall accuracy of MDCT was 77%. The most accurate sign helping the diagnosis was contiguous injury on either side of the diaphragm in single-entry penetrating trauma (sensitivity, 88%; specificity, 82%). Thus MDCT has high sensitivity and good specificity in detecting penetrating diaphragmatic injuries.

[Trauma mechanism and diagnosis of blunt diaphragmatic rupture]

BACKGROUND

Indirect diaphragmatic rupture (DR) is defined as acquired complete split of the diaphragm after blunt trauma and occurs in 1-5% of massively traumatized patients. The diagnosis is often difficult. However, particular trauma mechanisms and associated injuries may suggest the existence of DR.

METHODS

A retrospective study was done of 21 consecutive patients from 1993 to 2004 at an university hospital.

RESULTS

This study revealed a striking combination of DR with pelvic fractures (12/21, 57%). Of 19 polytraumatized patients, diagnosis was made initially in 13 (68%) and with a delay in six (32%). Right-sided injuries were common (8/21, 38%). Thus a 'protective' function of the liver does not exist. Diaphragmatic rupture can be missed in ventilated patients until extubation leads to herniation of abdominal organs into the thorax.

CONCLUSIONS

Diaphragmatic rupture should be excluded in all severely abdominally traumatized patients, in particular those with concomitant pelvic fracture. Computed tomography with oral contrast medium is diagnostic in most cases. Access by laparotomy should be preferred after acute trauma, since additional intra-abdominal injuries are frequent.

Imaging hemidiaphragmatic injury

The supine chest radiograph is the initial and most commonly performed imaging study to evaluate the thorax after trauma. Whenever the chest radiograph is equivocal or suspicious for acute diaphragmatic injury (DI), computed tomography (CT) is usually the next study of choice since it is both generally available and often used to examine other body regions in the patient after trauma. CT is usually diagnostic, particularly if supplemented by multiplanar reformation (MPR) obtained using thin-slice axial scanning and overlapping images for reformations. Magnetic resonance imaging (MRI) is potentially useful to assess the diaphragm if CT findings are indeterminate and the patient is stable enough to have the procedure. Simple T1-weighted spin-echo images in the sagittal and coronal orientation are usually sufficient to establish or exclude DI. This article reviews imaging modalities and strategies for diagnosing DI from blunt trauma.

Sinus cut-off sign: a helpful sign in the CT diagnosis of diaphragmatic rupture associated with pleural effusion

The objective of our study was to describe the "sinus cut-off" sign at CT in the diagnosis of diaphragmatic rupture in patients with blunt abdominal trauma complicated with pleural effusion, and evaluate its utility in an experimental model. Between January 2004 and March 2005, we observed an unusual interruption of costophrenic sinus at CT in three patients with blunt abdominal trauma accompanied with pleural effusion. This observation prompted us to evaluate the utility of this sign in an experimental model. Laparotomically, we created 2 cm diapragmatic lacerations at each hemidiaphragm in two rabbits and pushed up the abdominal viscera with omentum through the defect. To simulate hemothorax, we also injected 5-10 mL of diluted contrast material into the pleural space. Using a dual-slice helical CT scanner, limited thoracoabdominal CT examination was performed before and after injection of intrapleural contrast material. The images were analyzed for the presence of CT signs for diaphragmatic injury. The left posterior costophrenic sulcus was interrupted in all of the three patients with left pleural effusion. While it was associated with other findings of diaphragmatic injury, the "sinus cut-off sign" was the sole finding in one patient. The sinus cut-off sign was observed on the CT scans of 100% of the rabbits with a left and right sided diaphragmatic rupture. The "sinus cut-off sign" is useful and can increase the CT detection of acute diaphragmatic injury associated with pleural effusion.

Imaging of diaphragm injuries

Diaphragm injuries are uncommon consequences of blunt and penetrating trauma. Early diagnosis and repair prevent potentially devastating complications that typically result from visceral herniation through the posttraumatic diaphragm defect. Although clinical and radiographic manifestations frequently are nonspecific, the stalwarts of trauma imaging--chest radiography and CT--typically demonstrate these injuries. To render the appropriate diagnosis, the radiologist must be familiar with the varied imaging manifestations of injury, and maintain a high index of suspicion within the appropriate clinical setting.

Computed tomography without oral contrast solution for blunt diaphragmatic injuries in abdominal trauma

OBJECTIVE

The aim of this study was to estimate the sensitivity, specificity, and positive predictive value (PPV) of computed tomography (CT) without oral contrast for diaphragm injuries (DIs) in blunt abdominal trauma.

METHODS

We prospectively enrolled 500 consecutive "trauma-one" patients who received CT imaging and interpretation (CT-Read1) of the abdomen within 45 minutes of their arrival from July 2000 to December 2001. All patients were imaged without oral contrast but with intravenous contrast. Computed tomographic images were reviewed within 24 hours of admission by research radiologists (CT-Read2) blinded to CT-Read1. True DIs were determined hierarchically by either laparotomy or autopsy.

RESULTS

There were 9 patients with laparotomy or autopsy-proven blunt DIs; 8 of these injuries involved the left hemidiaphragm. The CT-Read1 correctly detected only 6 of 9 blunt DIs, thus missing 3 DIs. One of these involved the right hemidiaphragm, whereas the other 2 were left sided. There were no false-positive findings with CT-Read1 for blunt DI. The sensitivity and specificity of CT imaging with respect to DI were 66.7% (95% CI, 29.9%-92.5%) and 100% (95% CI, 99.2%-100%), respectively. The PPV for the test was 1.00 (95% CI, 0.65-1.00).

CONCLUSION

Although the low number of blunt DIs in this study limits its general applicability, CT imaging of the diaphragm without oral contrast appears to perform within the range of reported imaging techniques using oral contrast. Still, CT scanning appears to have an unsatisfactorily low sensitivity to be reliably used in eliminating the diagnosis of blunt DI.

Helical CT of blunt diaphragmatic rupture

OBJECTIVE

This study evaluated CT findings for signs of blunt diaphragmatic rupture.

MATERIALS AND METHODS

CT examinations of 179 blunt trauma patients, including 11 with left-sided and five with right-sided blunt diaphragmatic rupture, were reviewed by two staff radiologists who first decided by consensus on the presence or absence of 11 published signs of blunt diaphragmatic rupture and then formulated the diagnosis in terms of absence of, presence of, or suggestion of blunt diaphragmatic rupture. The significance of the findings was assessed by multivariate logistic regression. Four other reviewers interpreted the CT findings independently. They were asked first to formulate a diagnosis in terms of absence of, presence of, or suggestion of blunt diaphragmatic rupture and then to enumerate the findings supporting a diagnosis or suggestion of blunt diaphragmatic rupture. These findings were compared with those of the staff radiologists.

RESULTS

Diaphragmatic discontinuity, diaphragmatic thickening, segmental nonrecognition of the diaphragm, intrathoracic herniation of abdominal viscera, elevation of the diaphragm, and both hemothorax and hemoperitoneum were strong predictors of blunt diaphragmatic rupture (p < 0.001). The combination of the first three findings was 100% sensitive (16/16). The staff radiologists' sensitivity for diagnosing blunt diaphragmatic rupture was 100% (16/16). The four reviewers' sensitivities were 56.2% (9/16), 81.2% (13/16), 62.5% (10/16), and 87.5% (14/16).

CONCLUSION

Six of 11 signs were good predictors of blunt diaphragmatic rupture. Despite diaphragmatic thickening, focal defect and segmental nonrecognition had 100% cumulative sensitivity; the reviewers formulating the diagnosis before analyzing CT signs overlooked blunt diaphragmatic rupture on CT in 12.5-43.8% of the patients.

Multislice CT in thoracic trauma

The introduction of CT imaging in the 1970s revolutionized all aspects of medical care, perhaps nowhere more so than in the evaluation of acutely injured patients. Just as single-slice helical scanning was a great advance over conventional CT, the capabilities of MSCT are proving to be dramatically superior to single-slice methods. Improved contrast bolus imaging, thinner slices, and isotropic voxels should enable the trauma radiologist to identify both major organ system disruption and subtle injuries more promptly. Multiplanar and three-dimensional reconstructions, a forte of MSCT, facilitate rapid communication of disease states with surgeons and others involved in the care of injured patients. In many centers, whole-body CT is beginning to supplant plain films of the chest and spine in the evaluation of severe trauma victims; the cost-effectiveness of such methods is still under evaluation.

Helical CT with sagittal and coronal reconstructions: accuracy for detection of diaphragmatic injury

OBJECTIVE

The objectives of our study were to determine the accuracy of single-detector helical CT (including coronal and sagittal reconstructions) for the diagnosis of traumatic diaphragmatic injury, establish measurements for the thickness of the normal diaphragmatic crus, and describe an additional sign of diaphragmatic injury: active arterial extravasation of contrast material at the level of the diaphragm.

MATERIALS AND METHODS

The CT scans of 25 patients with surgically proven diaphragmatic injury and 22 patients with surgically confirmed uninjured diaphragms were blindly reviewed by five thoracic radiologists. Sagittal and coronal reconstructions were performed for 20 of the 25 patients with a proven diaphragmatic injury and for all the patients without a diaphragmatic injury. Scans were evaluated for findings suggestive of diaphragmatic injury and for associated injuries. Reviewers scored the usefulness of the reconstructed images for establishing the final diagnosis. Measurements of the right and left crura were performed to establish a threshold measurement that would enable radiologists to discriminate between a normal diaphragm and an injured diaphragm.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of helical CT were 84%, 77%, 81%, 81%, and 83%, respectively. Scans showing active arterial extravasation of contrast material enabled reviewers to correctly identify diaphragmatic injury in two patients. Reconstructed images confirmed the correct diagnosis in three patients but supported an incorrect diagnosis in two. The mean thickness of the diaphragmatic crura (right and left) was not significantly greater in patients with an injured diaphragm than in those with an uninjured diaphragm.

CONCLUSION

Helical CT shows good sensitivity, specificity, and accuracy for the diagnosis of diaphragmatic injury. Coronal and sagittal reconstructions are of limited use in establishing or refuting this diagnosis. Active arterial extravasation of contrast material near the diaphragm should raise suspicion for injury. Crus measurements cannot be used to reliably distinguish between injured and uninjured diaphragms.

Imaging of diaphragmatic injuries

Multiple imaging modalities are available for the preoperative diagnosis of diaphragmatic injury. Chest radiographs are the initial and most commonly performed imaging study to evaluate the diaphragm after trauma. When chest radiography is indeterminate, spiral computed tomography (CT) with thin sections and reformatted images is the next study of choice, particularly because most hemodynamically stable patients with blunt diaphragm injury will require an admission CT examination to evaluate the extent and anatomical sites of coexisting thoracoabdominal injuries. Magnetic resonance imaging is used to evaluate the diaphragm for patients with clinical suspicion but an indeterminate diagnosis after chest radiography and spiral CT.