Scholarly article on topic 'Multi-slice computed tomography for diagnosis of combined thoracoabdominal injury'

Multi-slice computed tomography for diagnosis of combined thoracoabdominal injury Academic research paper on "Clinical medicine"

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Abstract of research paper on Clinical medicine, author of scientific article — Jun Liu, Weidong Yue, Dingyuan Du

Abstract Purpose To investigate the diagnostic value of multi-slice computed tomography (MSCT) for combined thoracoabdominal injury. Methods A retrospective study was conducted to analyze the clinical data and MSCT images of 68 patients who sustained a combined thoracoabdominal injury associated with diaphragm rupture, and 18 patients without diaphragm rupture. All the patients were admitted and treated in the Chongqing Emergency Medical Center (a level I trauma center) between July 2005 and February 2014. There were 71 males and 15 females with a mean age of 39.1 years (range 13–88 years). Among the 86 patients, 40 patients suffered a penetrating injury, 46 suffered a blunt injury as a result of road traffic accident in 21 cases, fall from a height in 16, and crushing injury in 9. The MSCT images were retrospectively reviewed by two radiologists. The results of CT diagnosis were compared with surgical findings and/or follow-up results. Results Among the 86 cases, diaphragm discontinuity was found in 29 cases, segmental nonrecognition of the diaphragm in 14, diaphragmatic hernia in 21, collar sign in 14, dependent viscera sign in 18, elevated abdominal organs in 21, bowel wall thickening and/or hematoma in 6, and pneumoperitoneum in 8. CT diagnostic accuracy for diaphragm rupture was 88.4% in the right side and 90.7% in the left side. CT diagnostic accuracy for hemopneumothorax, pulmonary contusion, mediastinal hemorrhage, kidney and adrenal gland injuries was 100%, while for liver, spleen and pancreas injuries was 96.5%, 96.5%, 94.2% respectively. Conclusion To reach an early diagnosis of combined thoracoabdominal injury, surgeons and radiologists should be familiar with all kinds of images which might show signs of diaphragm rupture, such as diaphragm discontinuity, segmental nonrecognition of the diaphragm, dangling diaphragm sign, diaphragm herniation, collar sign, dependent viscera sign, and elevated abdominal organs.

Academic research paper on topic "Multi-slice computed tomography for diagnosis of combined thoracoabdominal injury"

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Chinese Journal of Traumatology

journal homepage: http://www.elsevier.com/locate/CJTEE

Original article

Multi-slice computed tomography for diagnosis of combined thoracoabdominal injury

Jun Liu a, Weidong Yue a, Dingyuan Du b' *

a Department of Radiology, Chongqing Institute of Accident & Emergency Medicine, Chongqing Emergency Medical Center, Chongqing 400014, China b Department of Cardiothoracic Surgery, Chongqing Institute of Accident & Emergency Medicine, Chongqing Emergency Medical Center, Chongqing 400014, China

ARTICLE INFO

Article history:

Received 23 September 2014 Received in revised form 24 October 2014 Accepted 15 November 2014 Available online 5 May 2015

Keywords: Diaphragm

Multidetector computed tomography Thoracoabdominal injuries

ABSTRACT

Purpose: To investigate the diagnostic value of multi-slice computed tomography (MSCT) for combined thoracoabdominal injury.

Methods: A retrospective study was conducted to analyze the clinical data and MSCT images of 68 patients who sustained a combined thoracoabdominal injury associated with diaphragm rupture, and 18 patients without diaphragm rupture. All the patients were admitted and treated in the Chongqing Emergency Medical Center (a level I trauma center) between July 2005 and February 2014. There were 71 males and 15 females with a mean age of 39.1 years (range 13—88 years). Among the 86 patients, 40 patients suffered a penetrating injury, 46 suffered a blunt injury as a result of road traffic accident in 21 cases, fall from a height in 16, and crushing injury in 9. The MSCT images were retrospectively reviewed by two radiologists. The results of CT diagnosis were compared with surgical findings and/or follow-up results.

Results: Among the 86 cases, diaphragm discontinuity was found in 29 cases, segmental nonrecognition of the diaphragm in 14, diaphragmatic hernia in 21, collar sign in 14, dependent viscera sign in 18, elevated abdominal organs in 21, bowel wall thickening and/or hematoma in 6, and pneumoperitoneum in 8. CT diagnostic accuracy for diaphragm rupture was 88.4% in the right side and 90.7% in the left side. CT diagnostic accuracy for hemopneumothorax, pulmonary contusion, mediastinal hemorrhage, kidney and adrenal gland injuries was 100%, while for liver, spleen and pancreas injuries was 96.5%, 96.5%, 94.2% respectively.

Conclusion: To reach an early diagnosis of combined thoracoabdominal injury, surgeons and radiologists should be familiar with all kinds of images which might show signs of diaphragm rupture, such as diaphragm discontinuity, segmental nonrecognition of the diaphragm, dangling diaphragm sign, diaphragm herniation, collar sign, dependent viscera sign, and elevated abdominal organs. © 2015 Production and hosting by Elsevier B.V. on behalf of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. This is an open access article under the CC BY-NC-ND

license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

1. Introduction

Combined thoracoabdominal injury refers to visceral injuries in the thoracic and abdominal cavities, accompanied by diaphragm rupture at the same time. Respiratory and circulation dysfunction often occurs as a result of acute hemorrhage in the thoracic and abdominal cavities. Shock and death rate are high. Patients' clinical manifestations are complex and lack of specific signs.1 This study,

* Corresponding author. Tel.: +86 23 13983972798. E-mail address: dudingyuan@qq.com

Peer review under responsibility of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University.

by analyzing the clinical data and multi-slice computed tomography (MSCT) images of 86 trauma patients admitted in the Chongqing Emergency Medical Center (a level I trauma center) between July 2005 and February 2014, attempts to investigate the diagnostic value of MSCT for combined thoracoabdominal injury.

2. Materials and methods

2.1. Patients

In this series, 68 patients sustained combined thor-acoabdominal injury associated with diaphragm rupture and 18 patients without diaphragm rupture were admitted and treated in

http://dx.doi.org/10.1016/j.cjtee.2014.11.002

1008-1275/© 2015 Production and hosting by Elsevier B.V. on behalf of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

the Chongqing Emergency Medical Center (a level I trauma center) between July 2005 and February 2014. There were 71 males and 15 females with a mean age of 39.1 years (range 13—88 years). Among the 86 patients, penetrating injury was implicated in 40 patients, blunt injury in 46 consisting of road traffic accidents in 21 cases, fall from a height in 16, and crushing injury in 9. The clinical manifestations included pain in the chest and abdomen, dyspnea, chest discomfort, nausea, vomiting, coma, and hemorrhagic shock. Eighty-four patients received surgical treatments, including tho-racotomy in 10 patients, laparotomy in 68, both thoracotomy and laparotomy in 4, video-assisted thoracoscope surgery in 2.

2.2. CT scanning

The chest and abdomen were detected by 16 layers spiral CT machine (GE LightSpeed 16, GE Co. Ltd). Scan parameters were: tube voltage, 100—120 kV; effective tube current, 150—300 mA; pitch, 0.938:1; scanning layer thickness and layer spacing, 7.5 mm; FOV, 35 cm x 35 cm; rebuilding layer thickness, 1.25 mm; spacing, 1.0 mm. The data were transmitted to ADW 4.4 post-processing workstation.

Fig. 3. Axial CT image shows the stomach is in a dependent position along the posterior left ribs and contacted the posterior thoracic wall (dependent viscera sign).

Fig. 2. Coronal (A) and sagittal (B) contrast-enhanced reformatted CT images show right-sided diaphragm rupture, part of the liver herniated into the thorax through a small diaphragmatic defect, which is evident from the focal constriction of herniated liver called "collar".

Fig. 4. Coronal reformatted CT image shows part of the stomach, colonic loops, and abdominal fat herniated into the thorax and elevated abdominal organs signs.

2.3. Image analysis

All images were analyzed by two radiologists, and the analytic parameters included diaphragm rupture, hemopneumothorax, pulmonary contusion, rib fracture, cardiac and major thoracic vessel injury, mediastinal hematoma, liver, spleen, kidney, and pancreas injuries, hollow viscus and mesenteric injuries.

2.4. Statistical analysis

CT results were compared with surgical findings and/or follow-up results. The diagnostic sensitivity, specificity, accuracy were

calculated. The data were processed by SPSS 16.0 statistical software.

3. Results

Among the 86 patients, diaphragm rupture was found in 52 patients by CT examination including left-sided diaphragm rupture in 33 and right-sided in 19, diaphragm discontinuity (Figs. 1 and 5) in 29, segmental nonrecognition of the diaphragm in 14, and dangling diaphragm sign (Figs. 1 and 5) in 13. Diaphragmatic hernia in 21 cases (Figs. 1,2 and 4) including 14 cases in the left and 7 in the right, collar sign in 14 (Fig. 2), dependent viscera sign in 18 (Fig. 3), elevated abdominal organs in 21 (Fig. 4), and simultaneous pneumothorax and pneumoperitoneum in 8. Some patients simultaneously had more than one signs. The herniated viscera included the stomach, greater omentum, bowel, liver, and spleen. Hemop-neumothorax was found in 59 cases, pulmonary contusion in 38, ribs and sternal fracture in 47, cardiac injury in 4 (Figs. 6 and 7), mediastinal hematoma in 19, liver contusion in 26, spleen rupture in 30, kidney injury in 20, pancreas injury in 8, adrenal hematoma in 12, hollow viscus injury in 8, and mesenteric hematoma in 9 (Fig. 8). Pneumoperitoneum was found in 8 cases and hemoper-itoneum in 49 cases. Some patients were complicated by pelvic, vertebral body, limb fractures and craniocerebral injury.

Surgical findings and/or follow-up results ascertained 68 cases of combined thoracoabdominal injury associated with diaphragm rupture, in whom 51 cases were diagnosed by CT scanning, and thus 17 cases were false negative results by CT. The other 17 cases of thoracoabdominal injury without diaphragm rupture were confirmed by surgical exploration and/or follow-up, but they were missed out by CT. The last 1 case was a false positive. Among the 68 patients with diaphragm rupture, the left side was in 39 cases and right side in 29. The defective diameter was more than 10 cm in 11 cases. Diaphragmatic hernia was confirmed in 22

Fig. 5. A 43 years-old male patient sustained penetrating injury at left lower chest wall. A: The axial CT image at admission shows left diaphragm rupture and segmental diaphragmatic defect sign. B: Ruptured diaphragm is repaired by video-assisted thoracoscope surgery. Postoperation axial CT image shows local diaphragm continuity.

Fig. 6. Axial CT image shows penetrating cardiac injury and a large amount surgery.

of gas and blood

of anterior wall of right ventricular is confirmed by

Fig. 7. Sagittal reformatted CT image (A) and axial CT image (B) show bone fragments of the sternum shifted into the thorax, pericardium hemorrhage, the pericardial fat edema in front of right ventricular. Right-sided diaphragm and right ventricular anterior wall rupture are found by surgery.

pulmonary laceration repair in 9, liver repair in 17, splenectomy in 27 and spleen repair in 2, pancreas repair or partial resection in 9. Nine patients with kidney lesion were treated by interventional renal artery embolization, renal repair or resection. Mesenteric hematoma reduction was done in 8 cases and hollow viscus repair in 9 cases. Among these patients, 13 died of serious craniocerebral trauma and/or hemorrhagic shock. The results of visceral injury diagnosed by CTand surgical findings are shown in Table 1.

4. Discussion

Fig. 8. Axial CT image shows hepatic flexure injury of the colon, characterized by bowel wall thickening and hematoma. Bowel wall laceration is found by surgery.

cases. The ruptured diaphragm was repaired by laparotomy in 58 cases, by thoracotomy in 8, by video-assisted thoracoscope surgery in 2 (Fig. 5). Other surgical procedures included right ventricular myocardial repair in 3 cases, pericardial repair in 2,

Combined thoracoabdominal injury strictly refers to a thor-acoabdominal visceral injury concurrent with diaphragm rupture caused by the same factors at the same time. If it is not associated with diaphragm rupture, the injury can only be called thor-acoabdominal multiple injuries. Therefore, it is important to distinguish whether there is a diaphragm rupture in the diagnosis of thoracoabdominal injuries. Diaphragm rupture is generally caused by blunt attack on the upper abdomen or lower chest, or by penetrating injury to the thoracoabdominal juncture.

Combined thoracoabdominal injury is serious and complex. The symptoms of diaphragm rupture are often obscured by other injuries, so missed diagnosis is not rare. Since these patients often have irregular breathing and severe hemorrhagic shock, quickly

Table 1

CT diagnostic results and surgical findings and/or follow-up results of visceral injury.

Visceral injury Diagnosis by CT (cases) Diagnosis by surgery and/or follow-up (cases) Sensitivity (%) Specificity (%) Accuracy (%)

Diaphragm rupture Right-side 19 29 65.5 100 88.4

Left-side 33* 39 82.1 97.9 90.7

Thoracic visceral injury Hemopneumothorax 59 59 100 100 100

Pulmonary contusion 38 38 100 100 100

Mediastinal hematoma 19 19 100 100 100

Cardiac injury 4 5 80 100 98.8

Abdominal visceral injury Liver injury 26* 27 92.6 98.3 96.5

Spleen injury 30D 29 96.6 96.5 96.5

Pancreatic injury 8d 9 66.7 97.4 94.2

Kidney injury 20 20 100 100 100

Adrenal hematoma 12 12 100 100 100

Hollow viscus injury 8* 9 77.8 98.7 96.5

Note: * false positive in one case; false positive in two case.

completing CT scan using big pitch is necessary to get an accurate diagnosis.

When the wound is caused by penetrating injury and is located at the thoracoabdominal juncture or a blunt attack on the upper abdomen, combined thoracoabdominal injuries should be considered. To identify diaphragm rupture is important in the diagnosis of combined thoracoabdominal injury, but the diagnostic sensitivity and accuracy are relatively low. In this series, the diagnostic sensitivity and accuracy were 65.5%, 88.4% on the right side and 82.1%, 90.7% on the left side respectively. Radiologists and surgeons should be familiar with diaphragm rupture signs in making a diagnosis. Direct CT signs of diaphragm rupture include diaphragm discontinuity, segmental nonrecognition of the diaphragm, dangling diaphragm sign. Indirect CT signs include herniation through a defect, collar sign, dependent viscera sign, elevated abdominal organs, simultaneous pneumothorax and pneumo-peritoneum, simultaneous hemothorax and hemoperitoneum, as well as thickened diaphragm.2 Direct signs possess a high sensitivity to the diagnosis, but when the defect is at postero-diaphragm accompanied by hemothorax and/or pulmonary contusion and/or pulmonary atelectasis, the signs are usually not obvious. Herniation through a defect and collar sign strongly indicate diaphragm rupture, and are clearly visible on the coronal and sagittal CT images, so the diagnostic accuracy according to these signs is high in this series. The occurrence rate of diaphragm hernia was relatively higher in patients with diaphragm rupture caused by blunt injury than by penetrating injury (15 in 21 cases).3 Since penetrating diaphragm rupture is often small and not accompanied by diaphragmatic hernia, preoperative diagnosis is more difficult than that by blunt injury. Missed diagnosis happened in 17 cases in this series as a result of lack of characteristic signs. Among them 15 cases were penetrating injuries.

Simultaneous pneumothorax and pneumoperitoneum, or simultaneous hemothorax and hemoperitoneum are signs that strongly suggest diaphragm rupture,4,5 but other factors causing pneumoperitoneum should be excluded, such as hollow viscus injury, etc. When a fractured piece of the rib and/or the sternum horizontally shifts into the thorax, it is necessary to be vigilant to rule out diaphragm rupture.6 There were 4 such cases in this series, of whom one patient's diaphragm and myocardium were stabbed by the lower sternal fracture. Thickened diaphragm or elevated abdominal organs are the signs of diaphragm rupture, but the diagnosis is sometimes not reliable based only on these signs because a thickened diaphragm could be caused by diaphragm edema and retroperitoneal dropsy or congenital diaphragm variations, and thus easily lead to false positive. Phrenic nerve damage, gastrointestinal distention and lung collapse could also cause elevated diaphragm and lead to false positive. Therefore the diagnosis of diaphragm rupture should be combined with other signs. In this series, one patient was misdiagnosed with a diaphragm rupture because of predominant elevated left diaphragm, which was lastly confirmed by follow-up as a false positive.

In the diagnosis, lethal damage must be excluded firstly, such as cardiac and major thoracic vascular injuries. Their CT signs include pneumopericardium, hemorrhage in the pericardium, the discontinuity of cardiac wall, high density images around blood vessels in the mediastina. When sternal bone fragments move into the chest cavity, cardiac injury should be considered. Cardiac injury was diagnosed by CT in four patients and confirmed later by surgical finding as right ventricular rupture in 3 cases and pericardium tear in 1 case. There was 1 missed case owing to ignoring local peri-cardial fluid, in which a pericardial tear was found accompanied by the left-sided diaphragmatic hernia during surgery.

The overall diagnostic accuracy for hemopneumothorax, pulmonary contusion, mediastinal hematoma, and solid organ injuries

(liver, spleen, kidney and adrenal gland) were high in this series confirmed by surgical findings and/or follow-up: 100% for pulmonary contusion, hemopneumothorax, mediastinal hemorrhage, kidney injury, and adrenal gland hematoma; 96.5%, 96.5%, 94.2% for hepatic, spleen, and pancreas injuries respectively. The number of missed diagnosis for the liver, spleen, pancreas injuries was 2 cases, 1 case, and 3 cases respectively. The number of misdiagnosis was 1 case, 2 cases, 2 cases respectively. The reasons for false negative were considered as follows: poor image resolution caused by respiratory motion artifact, little density difference between the damaged and normal tissues, the interference of hemoperitoneum and bowel overlap. These factors influenced the pancreas more often than other solid organs. In addition, the reasons for false positive may also be due to apparent density differences between adjacent viscera. Enhanced scanning would help to identify any slight contusions in the solid organs, and also could detect any pancreatic duct injuries. By enhanced scanning, contusion area could be characterized by slight strengthening that was significantly lower than normal tissues. It is reported that the diagnostic accuracy for a pancreatic duct injury is more than 96% by enhanced multi-phase CT scanning.7 Artifacts had less influence on thoracic viscera than on abdominal ones, so the diagnostic accuracy was higher because of less false negatives and false positives.

The diagnosis of hollow viscus injury remains challenging. CT signs of bowel injury consists of pneumoperitoneum, discontinuity of hollow viscus wall, oral contrast extravasation, gas bubbles close to the injured hollow viscus, thickened bowel wall (>4 mm), bowel wall hematoma, intraperitoneal fluid of unknown source, and patchy bowel enhancement.8,9 Generally, bowel wall discontinuity and oral contrast extravasation are highly specific signs for the diagnosis of bowel perforation, however these signs were not seen in our series. Pneumoperitoneum, thickened bowel wall and bowel wall hematoma are signs strongly suggestive of bowel injury, but the following conditions causing pneumoperitoneum should be precluded: pneumoperitoneum caused by abdominal puncture or lavage, gas in the pleural cavity to the peritoneal cavity, gas from the birth canal.10 Thickened bowel wall should be distinguished with aggregated bowel loops so as to avoid false positives. Bowel wall hematoma is usually accompanied by mesenteric dropsy or hematoma. In this series, 8 patients were diagnosed as having stomach, small bowel or colon injury requiring operative repair including pneumoperitoneum, local bowel wall thickening, bowel wall hematoma, peripheral mesenteric dropsy or mesenteric hematoma. Seven patients were confirmed as hollow viscus injury by surgery, and one patient only had mesenteric injury, whose pneu-moperitoneum was caused by gas from the pleural cavity. Missed diagnosis was noticed in two cases.

In conclusion, the diagnosis of combined thoracoabdominal injury by MSCT is helpful to determine surgical methods, i.e. tho-racotomy or laparotomy. In the diagnosis of combined thor-acoabdominal injuries, identifying diaphragm rupture is vital.

This work was financially supported by the Nature Science Foundation of Chongqing Municipality (Grant No. 2012jjB10021) and the Medical Science Research Foundation of Chongqing Health Bureau (Grant No. 2010-1-52).

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