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 Table of Contents  
ORIGINAL ARTICLE
Year : 2015  |  Volume : 43  |  Issue : 2  |  Page : 60-65

The role of multidetector computed tomography in the diagnosis of traumatic orbital lesions in emergent settings


1 Department of Radiodiagnosis, Faculty of Medicine, Tanta University, Tanta, Egypt
2 Department of Ophthalmology, Faculty of Medicine, Tanta University, Tanta, Egypt

Date of Submission06-Jan-2015
Date of Acceptance02-Feb-2015
Date of Web Publication3-Jun-2015

Correspondence Address:
Alsiagy A Salama
Department of Radiodiagnosis and Imaging, Faculty of Medicine, Tanta University, Tanta, Gharbiya
Egypt
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DOI: 10.4103/1110-1415.158054

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  Abstract 

Introduction
The aim of this study was to evaluate the role of multiple detector computed tomography in the diagnosis of traumatic orbital lesions in emergent settings.
Patients and methods
Thirty patients (34 eyes) with eye injuries were included in this study. All patients were subjected to full history taking, clinical evaluation, and radiological assessment using multidetector computed tomography examination of the orbit. Both axial and coronal images were acquired with 3 mm sections. Cases were classified into four groups according to the anatomic site of lesions - orbital fractures, ocular lesions, adnexal lesions, and retrobulbar lesions.
Results
Diminution of vision was the most common presenting symptom (56.7%), and a compound orbital fracture was the most common eye injury following trauma (53.3%). Computed tomography (CT) showed positive findings including orbital fractures, ruptured globe, foreign bodies, and retrobulbar edema.
Conclusion
CT is the optimal imaging modality for revealing traumatic orbital injury. In an emergency setting, CT completes the clinical examination and allows appropriate care to be given for a wide range of traumatic lesions such as bony orbital fracture, lens traumatic complications, and posterior chamber sequels.

Keywords: computed tomography, traumatic orbital lesions, emergent settings


How to cite this article:
Dawoud M, Salama AA, Elatif HA, Ghoneim A. The role of multidetector computed tomography in the diagnosis of traumatic orbital lesions in emergent settings. Tanta Med J 2015;43:60-5

How to cite this URL:
Dawoud M, Salama AA, Elatif HA, Ghoneim A. The role of multidetector computed tomography in the diagnosis of traumatic orbital lesions in emergent settings. Tanta Med J [serial online] 2015 [cited 2018 Dec 19];43:60-5. Available from: http://www.tdj.eg.net/text.asp?2015/43/2/60/158054


  Introduction Top


Ocular injuries are an important cause of visual impairment worldwide, with a significant socioeconomic impact [1] . Although there is increased interest in eye trauma and injury prevention, such injuries remain a significant cause of ocular morbidity [2] .

Assessing traumatic orbital injuries is an important challenge for radiologists; this assessment is even more difficult when the orbital injury is associated with injuries involving multiple organs [3] .

The most common eye injuries among polytrauma patients are orbital wall fractures, periorbital swelling, hematoma, subconjunctival hemorrhage, ocular adnexal injuries, optic nerve injuries, and penetrating globe injuries [4] .

Blow-out fracture of the orbit is a common injury. However, not many cases are associated with massive subcutaneous emphysema, and even fewer cases are caused by minor trauma or are associated with barotrauma to the orbit due to sneezing, coughing, or vomiting [5] .

Orbital trauma is one of the most common reasons for ophthalmology specialty consultation in the emergency department setting. Computed tomography (CT) orbit can often detect certain types of foreign bodies, lens dislocation, ruptured globe, choroidal or retinal detachments, or cavernous sinus thrombosis and thus complement a bedside ophthalmic exam that can sometimes be limited in the setting of trauma. CT remains the workhorse for acute orbital trauma owing to its rapidity and ability to delineate bony abnormalities [6] .

Ultrasonography can be very useful for evaluating the globe and its contents; however, ultrasonography is contraindicated if a ruptured globe is suspected. MRI may be difficult to perform emergently; it is contraindicated if there is a possibility that a metallic intraorbital foreign body is present. CT is considered to be the top choice for evaluating orbital trauma [3] .

The best protocol is to obtain thin-section axial CT scans, and then perform multiplanar reformation. When evaluating a patient with an orbital injury, the radiologist should do the following:

  1. Evaluate the bony orbit for fractures, note any herniation of orbital contents, and pay particular attention to the orbital apex;
  2. Evaluate the anterior chamber;
  3. Evaluate the position of the lens (the lens may be displaced, and it may be either completely or partially dislocated);
  4. Evaluate the posterior segment of the globe, look for bleeds or abnormal fluid collections, and evaluate for radiopaque or radiolucent foreign bodies; and
  5. Evaluate the ophthalmic veins and the optic nerve complex, especially the orbital apex [7] .
The capability of modern scanners to acquire several slices simultaneously offers the decisive advantage of being able to achieve high volume scan speeds coupled with thin slice acquisition; with multislice CT, several aspects such as resolution, speed, volume, and power were improved. Comparisons of the preoperative condition with postoperative outcomes are easier with the axial/MPR/3D-CT protocol [8] ; thus, the aim of this study was to evaluate the role of multidetector computed tomography in the diagnosis of traumatic orbital lesions in emergent settings.


  Patients and methods Top


This study included 30 patients (34 eyes) (24 males and six females) and was conducted over a period of 12 months starting from May 2012 to May 2013. Their ages ranged from 5 to 60 years. All patients had eye injuries and were referred to the Diagnostic Radiology Department at Tanta University Hospital for CT evaluation.

All patients were subjected to the following:

History taking

After taking personal data, each patient was asked about the type, mechanism, and duration of trauma. History of ocular or systemic diseases was also taken to exclude nontraumatic eye symptoms.

Clinical evaluation

General examination

General examination included evaluation of blood pressure, pulse, and temperature.

Local examination of the eyes

Local examination of the eyes was performed by an ophthalmologist and included assessment of visual acuity, pupillary testing, fundus examination, and slit-lamp examination to assess injury of the anterior chamber, cornea, iris, and lens.

Multidetector CT

Multidetector computed tomography was performed on all patients in axial and coronal cuts with MPR and 3D reconstruction.

Technique of examination

CT technique

The most commonly accepted protocol for CT examination of the orbit is acquisition of both axial and coronal images; 3 mm sections in the axial and coronal planes were adequate.

Patient positioning

  1. Axial view: The patient was examined in the supine position with the beam parallel to the orbito-meatal line. The images of patients with trauma were studied in bone window setting to assess fractures, and soft tissue window setting was used to assess orbital soft tissue injuries.
  2. The axial sections included images of the entire brain, especially the retro-orbital optic apparatus (with additional magnified views of the orbits).
  3. Coronal view: Study of coronal sections was initiated at the lateral orbital rim (to avoid exposure of the radiosensitive lens) and continued to the posterior aspect of the optic canals, with the anterior clinoid or dorsum sella used as landmarks. The patient was examined (after exclusion of cervical spine injury) in the prone position with the neck hyperextended and the beam perpendicular to the orbito-meatal line. Coronal images are especially important as cross-sectional evaluation of all intraorbital structures is optimal (e.g. extraocular muscles, optic nerve sheath, nasal complex, vessels, and globe). This plane is also imperative for assessing the spread of disease from the surrounding structures (e.g. paranasal sinuses, trauma, and tumor).
  4. MPR and 3D reconstruction: These were performed for fractures for the purpose of imaging of trauma patients and to localize foreign bodies. The MPR images were viewed as thin as possible to detect subtle fractures, but when images were noisy the noise level was reduced by fusing thin slices into thicker images. This fusion of images may also give additional important information such as depth. Varying scan planes can help in avoiding excessive hardware artifacts.
  5. CT with intravenous contrast: Intravenous nonionic contrast material was given only in three cases, for those with suspected vascular injuries.
Scan parameters

  1. Slice thickness 2-3 mm.
  2. 120 kV and 150 mAs with scan time 1.5 s.
  3. A window width of 350-400 HU and a level of 80-100 HU. For the detection of bony changes, a bone window was used with a window width of greater than 1000 HU.
Statistical analysis

The collected data were tabulated and statistically analyzed using statistical package for social science, version 19 (SPSS Inc., Chicago, Illinois, USA) on a personal computer. Descriptive statistics were used and included percentage (%), mean (x), and SD.


  Results Top


Thirty patients (30) were included in this study; their ages ranged from 5 to 60 years, with a mean age of 38 ± 15.52 years. There were six female and 24 male patients, with a male to female ratio of 4 : 1. The most common cause of eye trauma was road traffic accidents, seen in 12 patients (40%), followed by assaults, in eight patients (26.6%), work accidents, in three patients (10%), falls in three patients (10%), and other causes in the remainder of cases (four patients). Seventeen patients (56.7%) complained of diminished visual acuity, seven patients (23.3%) complained of eye swelling, four patients (13.3%) complained of abnormal eye shape, three patients (10%) complained of decreased ocular motility, and four patients had other manifestations (neurologic, orthopedic) not related to the eye injury (e.g. loss of consciousness, inability to move a limb) [Table 1].
Table 1 Demographic and admission characteristics of the studied patients

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Orbital bony fractures were the most commonly reported injuries [Figure 1] and [Figure 2] and were seen in 15 patients (17 eyes = 50%). Seven patients showed isolated wall fractures, whereas 10 patients showed combined fractures [Figure 1] and [Figure 2]. In isolated fractures, three cases involved the floor, two cases involved the lateral wall, one case involved the medial wall, and one case involved the roof. In combined fractures, there were associated facial fractures. Four cases were classified as Le Forte type II and six cases showed both orbital floor and roof fractures [Table 2].
Figure 1: Blow-out trauma. CT axial cut (a) shows the fracture floor of the right eye, periorbital hematoma, subconjunctival gases, and air fluid level in the right maxillary sinus. Coronal and sagittal cuts (b, c) show the fracture floor and the lateral wall of the right orbit. 3D reconstructed image (d) shows fractures of the floor and lateral walls of the right orbit with fracture of the right maxillary bone. CT, computed tomography.

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Figure 2: CT axial cut (a) shows the fracture floor and medial wall of the right orbit, periorbital hematoma, and subcutaneous emphysema. Coronal cut (b) shows right proptosis, orbital roof fracture with displaced fragment, fracture floor, right lateral rectus muscle contusion, and herniation of orbital fat into the right maxillary sinus. 3D reconstructed image (c) shows the previously described fractures. CT, computed tomography.

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Table 2 Number and percentage of positive CT findings among the studied patients

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Open globe injuries were the second most commonly reported injury and affected 32.3% of eyes [Figure 3]. Ruptured globe was seen in six eyes (17.6%), intraorbital air in two eyes (5.9%), intraocular foreign bodies in two eyes (5.9%), and intraorbital foreign bodies in three eyes (8.8%) [Figure 3]. Closed globe injuries were seen in three eyes in the form of lid wounds, lens displacement, and vitreous hemorrhage [Figure 4] and [Table 2].
Figure 3: Multiple intraorbital and extraorbital foreign bodies (gunshot injury). CT axial cut (a) shows multiple, hyperdense, metallic foreign bodies in the right retrobulbar space associated with streak-like increased density of vitreous hemorrhage denoting globe penetration. Coronal cut (b) shows multiple metallic foreign bodies located in right and left eye globes. Sagittal cut (c) shows left metallic foreign body penetrating the left orbit. 3D reconstructed image (d) shows the exact location of each described foreign body and the number of intraorbital and extraorbital foreign bodies. CT, computed tomography.

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Figure 4: Blunt trauma. CT axial (a) and coronal (b) cuts show hyperdense vitreous hemorrhage involving the whole globe (hemophthalmia). CT, computed tomography.

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Nine patients showed ocular adnexal injuries associated with either orbital fractures or globe injuries: five patients with conjunctival hemorrhage, one patient with lid foreign body, one patient with conjunctival laceration, and two patients with extraocular muscle injuries [Table 2].

Three patients (three eyes) with retrobulbar injuries were seen in our study: two patients with carotid cavernous fistula (CCF) showing a dilated supophthalmic vein [Figure 5] and one case with retrobulbar edema (collection of fluid, hematoma in the retrobulbar space) [Table 2].
Figure 5: Right carotid cavernous fistula following old blunt trauma. CT examination: precontrast axial image (a) reveals proptosis of the right eye globe with asymmetric cavernous sinuses. Postcontrast axial image (b) reveals tortuous dilated engorged right superior ophthalmic vein in the arterial phase of the study. Coronal and sagittal reformatted contrast enhanced image (c, d) shows dilated tortuous right superior ophthalmic vein. CT, computed tomography.

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  Discussion Top


CT is the first-line modality for radiologic evaluation of the orbit in the acute setting [9] . In the current study, our aim was to analyze the role of CT as a useful diagnostic tool in the diagnosis of traumatic orbital lesions in emergent settings, especially when clinical examination is not possible or does not reach a final diagnosis to manage and avoid permanent vision loss.

In this series, 30 patients with clinically proven traumatic orbital lesions were encountered. Male patients were more commonly affected than female patients by eye trauma, with a male to female ratio of 4 : 1. Other studies on trauma epidemiology confirm the male predominance, with a male to female ratio varying between 1.25 and 5.5 [10],[11],[12] .

In the current study, ages ranged between 5 and 60 years, with a mean of 38 ± 15.52. In contrast to other studies, most of the patients were in the pediatric age group [10],[12],[13] . However, the proportion of pediatric eye injuries in this study was similar to that in two previous studies in the Mediterranean region [11],[14] .

In our study, road traffic accidents were the most common cause of trauma-associated eye injuries. These findings agreed with those of previous studies by Poon et al. [15] and Georgouli et al. [4] . Assaults represented a higher percentage than falls. This was in contrast to other studies by May et al. [16] and Georgouli et al. [4] , in which assaults were less common than falls. This is possibly due to the period of civil unrest that we experienced in Egypt after the revolution (January 2011).

The most commonly reported eye injury in our study was orbital wall fracture in 17 eyes (50%); this was associated in the majority of cases with periorbital swelling or hematoma. This percentage was in close agreement with a previous study by Georgouli et al. [4] but in contrast to another study by Poon et al. [15] , which showed a much lower percentage (9.1%) of orbital wall fractures.

Open globe injuries were second in frequency (about 32.3%). This percentage was lower than that reported in two other studies, one by Salvolini [17] (72%) and the other by Soliman and Macky [11] (80%).

In our study, ocular adnexal injuries were the third most commonly reported injury (26.5%) and retrobulbar lesions were reported in three eyes (8.8%). This agreed with previous studies, which put adnexal injuries before retrobulbar lesions [4],[11],[15] .

Proptosis following trauma can be attributed to a number of reasons. It may arise as a result of retrobulbar hemorrhage, swelling of the retrobulbar contents (following accumulation of air or edema), or from bony or soft tissue (e.g. brain) displacement into the retrobulbar region [18],[19] . Ultimately, these varied pathologies can result in a 'final common pathway' of ischemia to the optic nerve or retina, and, if not reversed, loss of vision will occur.

Retrobulbar hemorrhage is generally thought to be a common cause of acute proptosis in trauma. However, results of a prospective 6-year study performed to identify the nature of acute severe post-traumatic proptosis revealed that in all cases proptosis was due to retrobulbar edema and not hemorrhage [20] .

Post-traumatic CCF occurs as a result of laceration of the internal carotid siphon or one of its intracavernous branches. Irrespective of the etiology and location of CCF, shunting of blood between a high-flow arterial system and low-flow venous system produces increased vascular pressure in the venous system. Congestion within and around the cavernous sinus accounts for the clinical symptoms and possible adverse sequelae of CCF. Ohtsuka and Hashimoto [21] correlated enhanced CT findings of CCFs showing that the superior ophthalmic vein can be enlarged at the fistula site in 86-100% of cases on postcontrast CT. These findings were in agreement with our study in which sensitivity of CT reached up to 100% in the diagnosis of CCF based on superior ophthalmic vein dilatation. The limitation of this study was the small number of cases that were included.


  Conclusion Top


CT is the optimal imaging modality for revealing traumatic orbital injury. In an emergency setting, CT completes the clinical examination and allows appropriate care to be given for a wide range of traumatic lesions such as bony orbital fracture, lens traumatic complication, and posterior chamber sequels.


  Acknowledgements Top


Conflicts of interest

There are no conflicts of interest.

 
  References Top

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2.
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Grala IR, Palczewski P, B³a¿ M, Zmorzyñski M, Go³êbiowski M, Wanyura H. A peculiar blow-out fracture of the inferior orbital wall complicated by extensive subcutaneous emphysema: a case report and review of the literature. Pol J Radiol 2012; 2:64-68.  Back to cited text no. 5
    
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Cillino S, Casuccio A, Di Pace F, et al. A five-year retrospective study of the epidemiological characteristics and visual outcomes of patients hospitalized for ocular trauma in a Mediterranean area. BMC Ophthalmol 2008; 8:6.  Back to cited text no. 12
    
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Rahman I, Maino A, Devadason D, et al. Open globe injuries: factors predictive of poor outcome. Eye 2006; 20:1336-1341.  Back to cited text no. 13
    
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May DR, Kuhn FP, Morris RE, et al. The epidemiology of serious eye injuries from the United States Eye Injury Registry. Graefes Arch Clin Exp Ophthalmol 2000; 238:153-157.  Back to cited text no. 16
    
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Salvolini U. Traumatic injuries: imaging of facial injuries. Eur Radiol 2002; 12:1253-1261.  Back to cited text no. 17
    
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Gabrielli MA, Vieira EH, Gabrielli MF, et al. Orbital roof blow-in fracture: report of a case. J Oral Maxillofac Surg 1997; 55:1475-1478.  Back to cited text no. 18
    
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Larsen M, Wieslander S. Acute orbital compartment syndrome after lateral blow-out fracture effectively relieved by lateral cantholysis. Acta Ophthalmol Scand 1999; 77:232-233.  Back to cited text no. 19
    
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Perry M. Acute proptosis in trauma: retrobulbar hemorrhage or orbital compartment syndrome - does it really matter?. J Oral Maxillofac Surg 2008; 66:1913-1920.  Back to cited text no. 20
    
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Ohtsuka K, Hashimoto M. Clinical findings in a patient with spontaneous arteriovenous fistulas of the orbit. Am J Ophthalmol 1999; 127: 736-737.  Back to cited text no. 21
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
 
 
    Tables

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