Multi-slice computed tomography for diagnosis of ...

Chinese Journal of Traumatology 18 (2015) 27e32

H O S T E D BY

Contents lists available at ScienceDirect

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 b

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

a r t i c l e i n f o

a b s t r a c t

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

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 13e88 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/).

Keywords: Diaphragm Multidetector computed tomography Thoracoabdominal injuries

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,

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

* Corresponding author. Tel.: þ86 23 13983972798. E-mail address: [email protected] (DY. Du) Peer review under responsibility of Daping Hospital and the Research Institute of Surgery of the Third Military Medical University.

In this series, 68 patients sustained combined thoracoabdominal 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/).

28

J. Liu et al. / Chinese Journal of Traumatology 18 (2015) 27e32

Fig. 1. Sagittal (A) and coronal (B) reformatted CT images show that left diaphragm rupture is revealed by the segmental diaphragmatic defect sign and dangling diaphragm sign. The omentum has herniated into the thorax through the diaphragmatic defect. Abdominal fat is located above the diaphragm and positioned against the posterior thoracic wall.

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 13e88 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 thoracotomy 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, 100e120 kV; effective tube current, 150e300 mA; pitch, 0.938:1; scanning layer thickness and layer spacing, 7.5 mm; FOV, 35 cm 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”.


29

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

3. Results

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 followup results. The diagnostic sensitivity, specificity, accuracy were

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. Hemopneumothorax 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 hemoperitoneum 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 of gas and blood in the pericardium. The rupture of anterior wall of right ventricular is confirmed by surgery.

30


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 CT and surgical findings are shown in Table 1. 4. Discussion Combined thoracoabdominal injury strictly refers to a thoracoabdominal 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 thoracoabdominal 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

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, Table 1 CT diagnostic results and surgical findings and/or follow-up results of visceral injury. Visceral injury Diaphragm rupture

Right-side Left-side

Thoracic visceral injury

Hemopneumothorax Pulmonary contusion Mediastinal hematoma Cardiac injury

Abdominal visceral injury

Liver injury Spleen injury Pancreatic injury Kidney injury Adrenal hematoma Hollow viscus injury

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

Diagnosis by CT (cases)

Diagnosis by surgery and/or follow-up (cases)

Sensitivity (%)

19 33*

29 39

59 38 19 4

59 38 19 5

100 100 100 80

100 100 100 100

100 100 100 98.8

26* 30D 8D 20 12 8*

27 29 9 20 12 9

92.6 96.6 66.7 100 100 77.8

98.3 96.5 97.4 100 100 98.7

96.5 96.5 94.2 100 100 96.5

65.5 82.1

Specificity (%) 100 97.9

Accuracy (%) 88.4 90.7


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 pneumoperitoneum, 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 pericardial 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

31

(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 pneumoperitoneum 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. thoracotomy or laparotomy. In the diagnosis of combined thoracoabdominal injuries, identifying diaphragm rupture is vital. Fund 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). References 1. Wang ZG, Jiang YG, Yang ZH. Traumatic Surgery. Beijing: Science and Technology Literature Publishing Company; 2007:388. 2. Chen HW, Wong YC, Wang LJ, et al. Computed tomography in left-sided and right-sided blunt diaphragmatic rupture: experience with 43 patients. Clin Radiol. 2010;65:206e212.

32


3. Du DY. Comparative study on blunt and penetrating diaphragmatic injury. J Trauma Surg. 2007;9:478e480. 4. Murray JG, Caoili E, Gruden JF, et al. Acute rupture of the diaphragm due to blunt trauma: diagnostic sensitivity and specificity of CT. AJR Am J Roentgenol. 1996;166:1035e1039. 5. Gao JM, Gao YH, Zhao SH, et al. Diagnosis and treatment of traumatic diaphragmatic rupture. Chin J Traumatol. 2008;24:369e371. 6. Rees O, Mirvis SE, Shanmuganathan K. Multidetector-row CT of right hemidiaphragmatic rupture caused by blunt trauma: a review of 12 cases. Clin Radiol. 2005;60:1280e1289.

7. Wong YC, Wang LJ, Fang JF, et al. Multidetector-row computed tomography (CT) of blunt pancreatic injuries: can contrast-enhanced multiphasic CT detect pancreatic duct injuries? J Trauma. 2008;64:666e672. 8. Magu S, Agarwal S, Gill RS. Multi detector computed tomography in the diagnosis of bowel injury. Indian J Surg. 2012;74:445e450. 9. LeBedis CA, Anderson SW, Soto JA. CT imaging of blunt traumatic bowel and mesenteric injuries. Radiol Clin North Am. 2012;50:123e136. 10. Asanza-Llorente JA, Quesada-Peinado MC, Diaz-Oller J, et al. Pneumoperitoneum in polytraumatized patients without perforated hollow viscera. Cir Esp. 2007;82:364e366.