Radiologic differentiation of intraocular glass: evaluation of imaging techniques, glass types, size, and effect of intraocular hemorrhage

Clinical outcomes and characterization of intraocular foreign body injuries from a Canadian centre: a 20-year retrospective study and literature review

OBJECTIVE

To analyse assessment and management patterns of intraocular foreign body (IOFB) injuries in an urban Canadian setting, providing valuable clinical insights to contextualize management.

METHODS

Single-surgeon retrospective chart review from January 2002 to January 2023 examining IOFB patient demographics, investigations, treatments, complications, and best-corrected visual acuity (BCVA).

RESULTS

This study evaluated IOFBs in 32 eyes from 31 patients (96.8% male). Sizes ranged from 1 to 12 mm; 28 (87.5%) were metallic and 15 (46.9%) were work-related injuries. For diagnosis, 19 patients (61.3%) underwent computed tomography (CT) imaging, and 8 (25.8%) received B-scans, with CT detecting IOFBs in 100% of cases and B-scan in 87.5%. At final follow-up, 17 eyes (53.1%) achieved BCVA ≥20/40, up from 7 (23.3%) initially. Presenting BCVA ≥20/200 was associated with a final BCVA ≥20/40 (P = 0.027). The IOFB was extracted in 27 eyes (84.4%), retained in 4 (12.5%), and 1 (3.1%) required enucleation. Intravitreal antibiotics were administered in 19 eyes (59.4%), resulting in one presumed case of drug toxicity. Complications were present in 30 eyes (93.8%), totalling 119 recorded overall, with 72 (60.5%) occurring within the first 24 hours. Traumatic cataracts were most common in 27 eyes (84.4%). Less-common complications included siderosis and retinal detachment with proliferative vitreoretinopathy, each occurring in one eye (3.1%). Four eyes (12.5%) developed secondary glaucoma, with 3 cases in retained or delayed extractions.

CONCLUSIONS

The IOFB characteristics and patient demographics are consistent with other regions. CT scans were the most effective investigation tool. Extended follow-up is recommended to monitor complications, particularly in retained or significantly delayed extractions.

Computed tomography in traumatic orbital emergencies: a pictorial essay-imaging findings, tips, and report flowchart

Computed tomography (CT) is considered the gold standard technique for the assessment of trauma patients with suspected involvement of the eye and orbit. These traumas can result in dramatic consequences to visual function, ocular motility, and aesthetics. CT is a quick and widely available imaging modality, which provides a detailed evaluation of the orbital bony and soft tissue structures, an accurate assessment of the globes, and is used to guide the patients’ treatment planning. For a timely and accurate diagnosis, radiologists should be aware of fracture patterns and possible associated complications, ocular detachments and hemorrhages, and different appearances of intraorbital foreign bodies. This educational review aims to describe all post-traumatic orbital abnormalities that can be identified on CT, providing a list of tips and a diagnostic flowchart to help radiologists deal with this complex condition.

Management of a misidentified and misnumbered intraocular glass foreign body with an endoscope in a case of endophthalmitis

An endoscope is a useful adjunct for the retinal surgeon to overcome haze of a compromised anterior segment. It allows early surgery in trauma and infections which translates to better results. Intraocular glass foreign body is a challenging condition, demanding highly skilled surgical expertise. We present endoscopic removal of an intraocular foreign glass body in a badly traumatised and infected eye. The surgical challenge was accentuated by an imaging misdiagnosis of 'twin metallic foreign bodies'.

Detection of Intraorbital Foreign Bodies Using Magnetic Resonance Imaging and Computed Tomography

PURPOSE

We analyze the detectability of intraorbital foreign bodies (OrbFBs) of various types and sizes using computed tomography (CT) and magnetic resonance imaging using a three-Tesla machine (MRI 3 T).

METHODS

An ex vivo model of sheep eyes with preserved extraocular muscles and orbital fat tissue placed in the orbital cavity of the human skull was created for this study. Foreign bodies made of four different materials - plastic, bottle glass, stone and wood - each in three different sizes (large, intermediate and small) were inserted into the soft tissue of the orbit in the extraocular space. Each orbit was scanned by CT and MRI. Images were analyzed by a senior radiologist and underwent masked review by three oculoplastic surgeons.

RESULTS

Analysis of MRI and CT scans identified distinguishing characteristics for each of the four materials. This information was further integrated into a clinical algorithm. CT allowed easier identification of most of the embedded materials compared to MRI. Smaller OrbFB size was associated with lower detectability. Review of CT yielded 94.4% agreement between oculoplastic specialists in detecting OrbFbs using CT scans and allowed detection of most OrbFBs. In contrast, the overall agreement with MRI was lower: 66.7% with T1 MPRAGE, 50% with T1TSE, 88.9% with T2 TSE and 72.2% with T2 TSE FS. Plastic was the most difficult material to detect in all size categories.

CONCLUSIONS

CT offers a clear advantage over MRI for detecting and localizing nonmetallic OrbFBs of all sizes, except for plastic. Plastic OrbFBs can be detected with CT depending on size but are more visible in MRI scans.

Ex vivo porcine model for eye, eyelid, and orbit movement analysis of 4-mm ferromagnetic foreign bodies in MRI

PURPOSE

Ferromagnetic foreign bodies (FFB) present during magnetic resonance imaging (MRI) explorations can lead to tissue injury due to movement, especially in and around the eyes. Ferromagnetic foreign bodies located in the intraocular area, eyelids, and orbit are thus prohibited from undergoing MRI. The aim of the study was to analyze movement of 4-mm ferromagnetic foreign bodies in MRI in the eye, eyelid, and orbit using computed tomography (CT) scan.

METHOD

We developed a porcine model using 12 quarters of fresh porcine heads. Each porcine head included one whole orbit with the ocular globe, orbital fat, muscles, and eyelids. Four-millimeter FFB were implanted in the eye within 2 days post-slaughter, and images were acquired within 5 days post-slaughter. Four-millimeter FFB movement was analyzed after 1.5-Tesla (T) MRI. Four locations were tested: intravitreous, suprachoroidal, intraorbital fat, and intrapalpebral. Movement analysis was assessed using computed tomography (CT) scan.

RESULTS

The intravitreous ferromagnetic ball moved 14.0 ± 8.8 mm (p < 0.01), the suprachoroidal ball moved 16.8 ± 5.4 mm (p < 0.01), the intraorbital fat ball moved 5.8 ± 0.9 mm (p > 0.05), and the intrapalpebral ball moved 2.0 ± 0.4 mm (p > 0.05).

CONCLUSION

The ex vivo porcine model was able to study FFB movement. The 4-mm ferromagnetic balls moved in intravitreous and in suprachoroidal locations after MRI.

Clinical outcomes and epidemiology of intraocular foreign body injuries in Cork University Hospital, Ireland: an 11-year review

BACKGROUND/AIMS

To describe the epidemiology, outcomes, and prognostic factors of intraocular foreign body (IOFB) injuries at a tertiary ophthalmic referral centre in Cork University Hospital, Ireland.

METHODS

A retrospective review of 23 eyes with IOFB that presented to Cork University Hospital (CUH) from January 2009 to December 2019 was performed. The mechanism and characteristics of IOFB injury were all noted. This data was collated and analysed to ascertain the epidemiology of IOFB injury in CUH and to describe the prognostic factors affecting visual outcome following IOFB injury.

RESULTS

There was a 100% male prevalence. The mean age was 37.4 years. The majority of IOFBs were metal in nature and were acquired by hammering, often while working and frequently in the absence of personal protective equipment (PPE). The route of entry for the IOFB was via the cornea in 70% of cases. Fifty-two percent of cases were clinically detectable and 43% of cases were only identifiable on CT (computed tomography) imaging. Eighty-seven percent of cases underwent surgery on the same day as presentation. There was no incidence (0%) of endophthalmitis. Seventeen percent of cases developed post-operative retinal detachment (RD). The mean pre-operative VA was 0.79 LogMAR (6/38 Snellen equivalent-SE) compared to a mean VA of 0.58 LogMAR (6/24 SE) following surgery.

CONCLUSIONS

This review provides important epidemiological data for IOFB injuries in Ireland. It also adds some useful information to the literature in relation to prognostic factors and lens status post IOFB injury.

Siderotic glaucoma without detectable intraocular foreign body in a pseudophakic eye: a case report

Background

Ocular siderosis is induced by a retained intraocular foreign body (IOFB) containing iron and can present as siderotic glaucoma. We report a rare case of histopathologically proven siderotic glaucoma in a middle-aged blacksmith with a preceding history of ocular trauma but no radiologically detectable IOFB.

Case presentation

A 42-year-old blacksmith presented with an elevation of intraocular pressure (IOP) in left eye showing iris heterochromia and brownish deposits throughout the trabecular meshwork (TM). Preoperative ophthalmic examination did not reveal any retained IOFBs. Electroretinography showed the classic changes of retinal degeneration in ocular siderosis. Histopathologic staining of the TM verified the presence of iron deposits.

Conclusion

This case underlines the importance of the close monitoring of patients with a history of ocular trauma and highlights the necessity of electroretinography, histopathologic study, and detailed ophthalmic examination in the diagnosis of siderotic glaucoma, even if there is no definite radiologically detectable IOFB.

Multimodal imaging features of intraocular foreign bodies

Objective: To determine the imaging approach for evaluating intraocular foreign bodies (IOFBs) by comparing the ability of different modalities [plain film x-ray, computed tomography (CT), magnetic resonsance imaging (MRI), convetional ultrasound, and ultrasound biomicroscopy] to detect and characterize IOFBs.Methods & Design: Systematic review of the literature.Results: CT is the most practical first step for evaluating patients with suspected IOFBs because it can detect a wide range of IOFB types at small limitis of detection. MRI and ultrasound are best reserved as adjunctive tests in most cases although these tests may provide important insights especially with wood, plastic, and glass IOFBs. Imaging characteristics of metal, wood, glass, plastic, stone, concrete, and graphite IOFBs are reviewed.Conclusion: Understanding the limits of detection for each IOFB type and imaging modality as well as the characteristic features of different IOFBs is of paramount importance to optimizing the management of ocular trauma patients.

Diagnosis of Traumatic Eye Injuries With Point-of-Care Ocular Ultrasonography in the Emergency Department

STUDY OBJECTIVE

Traumatic eye injuries are common emergency department presentations worldwide, and diagnosis may be delayed because of concurrent injuries and lack of guidelines in regard to the utility of clinical examination, computed tomography (CT), and point-of-care ultrasonography. In this study, we compare point-of-care ultrasonography with ophthalmologist clinical examination and CT for 6 types of traumatic eye injury.

METHODS

We conducted a prospective cohort study evaluating patients with suspected traumatic eye injury who were recruited at an academic medical center in Tabriz, Iran. Each patient was evaluated by an emergency physician with point-of-care ultrasonography using a 7- to 15-MHz linear transducer, by a radiologist with orbital CT imaging, and by an ophthalmologist with a complete bedside ocular examination. Obtained results were tabulated. Sensitivity, specificity, and likelihood ratios were subsequently calculated. Cohen's κ was assessed to evaluate the agreement between ocular point-of-care ultrasonography with orbital CT and point-of-care ultrasonography with complete bedside ocular examination.

RESULTS

Two hundred thirty-two patients (351 eyes) with suspected traumatic eye injury were included. In all measures of accuracy, diagnosis by point-of-care ultrasonography compared favorably with CT and a complete bedside ocular examination by an ophthalmologist in the 6 ocular injury patterns included in this study. Compared with CT imaging, point-of-care ultrasonography provided a specificity of 99.4% (95% confidence interval [CI] 97.8% to 99.9%) and a sensitivity of 96.8% (95% CI 83.3% to 99.9%) in the diagnosis of lens dislocation, and a specificity of 99.7% (95% CI 98.3% to 100.0%) and sensitivity of 95.7% (95% CI 78.1% to 99.9%) in the diagnosis of retrobulbar hematoma. Compared with complete bedside ocular examination by an ophthalmologist, point-of-care ultrasonography provided a specificity of 98.7% (95% CI 96.7% to 99.6%) and sensitivity of 97.8% (95% CI 88.2% to 99.9%) in the diagnosis of vitreous hemorrhage. In all injury types, positive likelihood ratios were high and negative ones were low.

CONCLUSION

Point-of-care ultrasonography demonstrates high sensitivity and specificity in the diagnosis of traumatic eye injury, and represents a valuable diagnostic tool in addition to orbital CT and complete beside ocular examination by an ophthalmologist in the diagnosis of traumatic eye injury.

Pterygium surgery combined with the removal of a missed occult iris foreign body detected incidentally during pterygium examination: a case report

Background

An occult foreign body may be retained in patient with small self-sealing wound and no decreased visual acuity without complete examination. Here we report a case of a retained occult ferrous iris foreign body detected incidentally during pterygium examination.

Case presentation

A 69-year-old man presented to our ophthalmology department because of foreign body sensation and persistent redness in both eyes for 2 years. In the left eye, a pterygium, paracentral corneal opacity and a vertically oval pupil were observed. Ultrasound biomicroscopy and gonioscopy revealed a retained metallic-like foreign body partially embedded in the inferior peripheral iris. Pterygium surgery and the removal of the retained iris foreign body were performed simultaneously. No recurrent pterygium or residual foreign body was found during follow-up.

Conclusions

A thorough history should be obtained and complete physical examination should be performed in patients with ocular self-sealing wounds to prevent missed intraocular foreign bodies, which may result in potential sight-threatening ocular complications.

Radiological identification and analysis of soft tissue musculoskeletal calcifications

Abstract

Musculoskeletal calcifications are frequent on radiographs and sometimes problematic. The goal of this article is to help radiologists to make the correct diagnosis when faced with an extraosseous musculoskeletal calcification. One should first differentiate a calcification from an ossification or a foreign body and then locate the calcification correctly. Each location has a specific short differential diagnosis, with minimal further investigation necessary. Intra-tendon calcifications are most frequently associated with hydroxyapatite deposition disease (HADD). In most cases, intra-articular calcifications are caused by calcium pyrophosphate dihydrate (CPPD) crystal deposition disease. Soft tissue calcification can be caused by secondary tumoural calcinosis from renal insufficiency, or collagen vascular diseases and by vascular calcifications, either arterial or venous (phlebolith).

Teaching Points

• Calcifications have to be differentiated form ossification and foreign body.

• A musculoskeletal MRI study must always be correlated with a radiograph.

• The clinical manifestations of calcifications may sometimes mimic septic arthritis or sarcoma.

• HADD and CPPD crystal deposition have a distinct appearance on radiograph.

• Calcinosis is more frequently caused by chronic renal failure and scleroderma.

CT in the Evaluation of Acute Injuries of the Anterior Eye Segment

OBJECTIVE

Slit-lamp ophthalmologic examination and ocular B-scan sonography of the globe are frequently constrained by technical limitations in the setting of traumatic orbital injury. The main purpose of this study was to evaluate the diagnostic performance of CT in acute anterior segment ocular injuries as an adjunctive diagnostic modality.

MATERIALS AND METHODS

We retrospectively identified 122 patients who presented to the emergency department from April 2011 through April 2016 with recent direct trauma to the anterior segment of the eye. Deidentified multiplanar thin-slice CT images were reviewed by two subspecialty board-certified neuroradiologists for the presence of anterior segment rupture and hyphema, as well as lens, ciliary body, and lacrimal gland injury. The CT findings were compared to slit-lamp, B-scan ultrasound, or operative data as the reference standard.

RESULTS

The neuroradiologists' CT evaluation showed high sensitivity of 87.2% (95% CI, 74.3-95.2%) and specificity of 97.3% (95% CI, 90.7-99.7%) in diagnosing anterior globe rupture with high interrater agreement (κ = 0.876; 95% CI, 0.787-0.965). Detection of lens dislocation and anterior hyphema showed a sensitivity and specificity of 88.0% and 90.7% and 77.4% and 88.4%, respectively. A shallow anterior chamber was detectable with a sensitivity of 89.2% and specificity of 87.1%. This critically important sign predicted anterior globe rupture in 39 of 47 patients (odds ratio, 68.25; p < 0.0001).

CONCLUSION

Subtle ocular findings are readily detectable at CT and can provide valuable information to the ophthalmologist concerning acute trauma to the ocular anterior segment.

A missed diagnosis of multiple intraocular foreign bodies for 21 years

A 30-year-old patient went to the emergency department because of a chemical burn to the left eye more than 10 days ago by toilet cleanser. Surprisingly, a small piece of glass was found in the inferior anterior chamber in the same eye. The visual acuity was counting fingers. There was conjunctival congestion, corneal oedema and Descemet's membrane striae. And there was also a corneal leukoma around 4 to 5 o'clock. Through repeated questioning he recalled that he was injured by an exploded light bulb around 21 years ago. He was asymptomatic until he saw "something moving" in front of the left eye one month ago. Computed tomography (CT) scanning, ultrasonography, ultrasound biomicroscopy (UBM), anterior segment optical coherence tomography (AS-OCT) verified the presence of multiple intraocular foreign bodies (IOFBs) in the anterior chamber and vitreous cavity. B-scan verified the IOFB in the vitreous cavity. Thus, he was diagnosed with corneal chemical burn, IOFBs and corneal leukoma of the left eye. The IOFB in the anterior chamber was removed through surgery. An attempt was made to remove the IOFB in the vitreous cavity with electromagnet, but it was not successful. Vitrectomy could not be performed as it was hindered by the opacity of cornea. After surgery, the visual acuity remained counting fingers and the corneal oedema still existed. This case is a reminder that a detailed history taking, a thorough physical examination and modern imaging techniques are beneficial for establishing the diagnosis and treatment of IOFBs.

Acute ocular traumatic imaging: what the radiologist should know [corrected]

Acute ocular trauma accounts for a substantial number of emergency department visits in the USA, and represents a significant source of disability to patients; however, the orbits remain a potential blind spot for radiologists. The goal of this article is to review the relevant anatomy of the orbit and imaging findings associated with commonly encountered acute ocular traumatic pathology, while highlighting the salient information which should be reported to the ordering clinician. Topics discussed include trauma to the anterior and posterior chamber, lens dislocations, intraocular foreign bodies, and open and contained globe injuries.

EX VIVO MODEL FOR THE CHARACTERIZATION AND IDENTIFICATION OF DRYWALL INTRAOCULAR FOREIGN BODIES ON COMPUTED TOMOGRAPHY

BACKGROUND

The study was inspired after the authors encountered a patient with a penetrating globe injury due to drywall, who had retained intraocular drywall foreign body. Computed tomography (CT) was read as normal in this patient. Open globe injury with drywall has never been reported previously in the literature and there are no previous studies describing its radiographic features.

METHODS

The case report is described in detail elsewhere. This was an experimental study. An ex vivo model of 15 porcine eyes with 1 mm to 5 mm fragments of implanted drywall, 2 vitreous only samples with drywall and 3 control eyes were used. Eyes and vitreous samples were CT scanned on Days 0, 1, and 3 postimplantation. Computed ocular images were analyzed by masked observers. Size and radiodensity of intraocular drywall were measured using Hounsfield units (HUs) over time.

RESULTS

Intraocular drywall was hyperdense on CT. All sizes studied were detectable on Day 0 of scanning. Mean intraocular drywall foreign body density was 171 ± 52 Hounsfield units (70-237) depending on fragment size. Intraocular drywall foreign body decreased in size whereas Hounsfield unit intensity increased over time.

CONCLUSION

Drywall dissolves in the eye and becomes denser over time as air in the drywall is replaced by fluid. This study identified Hounsfield Units specific to intraocular drywall foreign body over time.

Approach to Management of Eyes with no Light Perception after Open Globe Injury

Loss of light perception (LP) after open globe injury (OGI) does not necessarily mean the patient will have permanent complete visual loss. Findings that seem to be associated reliably with permanent profound vision loss after OGI include optic nerve avulsion, optic nerve transection, and profound loss of intraocular contents, which can be identified with CT/MRI imaging albeit with varying degrees of confidence. Eyes with NLP after OGI that undergo successful primary repair with intact optic nerves may be considered for additional surgery, particularly if there is: (1) recovery of LP on the first day after primary repair; (2) treatable pathology underlying NLP status (e.g., extensive choroidal hemorrhage, dense vitreous and subretinal hemorrhage); (3) NLP in the fellow eye. We counsel patients that the chance of recovering ambulatory vision under these circumstances is very low (~5%).

Intraocular foreign bodies: A review

Intraocular foreign body injuries may result in a wide range of intraocular pathology and visual outcomes based on the mechanism of injury, type of foreign body, and subsequent complications. We have reviewed the literature to describe the epidemiology and mechanisms of such injuries; types of foreign bodies; imaging tools for diagnosis; current trends in management, presurgical, and surgical interventions; as well as visual prognosis and potential complications. The purpose of this review is to familiarize clinicians with the recent advances in diagnosis and management of such injuries.

[Accuracy and relevance of CT volumetry in open ocular injuries with intraocular foreign bodies]

BACKGROUND/OBJECTIVES

The aim of the study was to evaluate the volume of intraocular foreign bodies (IOFB) using computed tomography (CT) volumetry as a prognostic factor for clinical outcome in open ocular injuries.

PATIENTS AND METHODS

This study compared the volume of 11 IOFBs more than 5 mm(3) in size based on CT volumetry with the real size determined by in vitro measurement. A retrospective evaluation of clinical data, visual acuity, complications and relation of size of IOFBs with clinical outcome in 33 patients (mean age 41.0 ± 13.5 years) with open ocular injuries treated at our department between January 2005 and December 2010 was carried out.

RESULTS

No significant differences were found between pairwise in vitro measurement and CT volumetric size (p = 0.07). All patients were surgically treated by pars plana vitrectomy. The mean follow-up time was 7.6± 6.2 months and the mean preoperative best corrected visual acuity (BCVA) was 0.063 ± 0.16 (logMAR 1.2 ± 0.79). Postoperatively, a mean BCVA of 0.25 ± 0.2 (logMAR 0.6 ± 0.69) could be achieved. Clinical outcomes were significantly better in injuries with small IOFBs measuring < 15 mm(3) (p = 0.0098).

CONCLUSIONS

The use of CT volumetry is an accurate method for measurement of IOFBs. Exact data about the size and measurement of volume are also an important factor for the prognosis of clinical outcome in open ocular injuries with IOFBs and CT volumetry can also provide important information about the localization of IOFBs.

Injuries of the globe: what can the radiologist offer?

Traumatic ocular injuries are a significant cause of blindness and visual deficits. In the setting of acute orbital trauma, urgent ophthalmologic evaluation and intervention are critical in preserving vision. However, in the acute trauma setting, clinical evaluation of the globe may be difficult in the presence of surrounding periorbital soft-tissue swelling and other associated injuries, and patient cooperation may be limited because of unresponsiveness, altered mentation, or sedation. Often, rapid access to imaging is part of the initial diagnostic evaluation, and radiologists may be the first to identify traumatic injuries of the globe. Because of this, radiologists should be familiar with normal orbital and globe anatomy at various imaging modalities and have a thorough understanding of the various patterns of ocular injury and their imaging appearances. Radiologists should also be familiar with the various mimics of ocular injury, including congenital and acquired conditions that may alter the shape of the globe, various types of ocular calcifications, and the different types of material used to treat retinal detachment. Such knowledge may help radiologists make accurate diagnoses, which facilitates prompt and appropriate patient care.

Penetrating ocular trauma associated with blank cartridge

Background

Blank cartridge guns are generally regarded as being harmless and relative safe. However recent published articles demonstrated that the gas pressure from the exploding propellant of blank cartridge is powerful enough to penetrate the thoracic wall, abdominal muscle, small intestine and the skull. And there has been a limited number of case reports of ocular trauma associated with blank cartridge injury. In addition, no report on case with split extraocular muscle injury with traumatic cataract and penetrating corneoscleral wound associated with blank cartridge has been previously documented. This report describes the case of patient who sustained penetrating ocular injury with extraocular muscle injury by a close-distance blank cartridge that required surgical intervention.

Case presentation

A 20-year-old man sustained a penetrating globe injury in the right eye while cleaning a blank cartridge pistol. His uncorrected visual acuity at presentation was hand motion and he had a flame burn of his right upper and lower lid with multiple missile wounds. On slit-lamp examination, there was a 12-mm laceration of conjunctiva along the 9 o'clock position with two pinhole-like penetrating injuries of cornea and sclera. There was also a 3-mm corneal laceration between 9 o'clock and 12 o'clock and the exposed lateral rectus muscle was split. Severe Descemet's membrane folding with stromal edema was observed, and numerous yellow, powder-like foreign bodies were impacted in the cornea. Layered anterior chamber bleeding with traumatic cataract was also noted. Transverse view of ultrasonography showed hyperechoic foreign bodies with mild reduplication echoes and shadowing. However, a computed tomographic scan using thin section did not reveal a radiopaque foreign body within the right globe.

Conclusion

To our best knowledge, this is the first case report of split extraocular muscle injury with traumatic cataract and penetrating ocular injury caused by blank cartridge injury. Intraocular foreign bodies undetectable by CT were identified by B-scan ultrasonography in our patient. This case highlights the importance of additional ultrasonography when evaluating severe ocular trauma. And ophthalmologists should consider the possibility of penetrating injury caused by blank ammunition.

A systematic approach to CT evaluation of orbital trauma

Computed tomography (CT) is widely used in the initial evaluation of patients with craniofacial trauma. Due to anatomical proximity, craniofacial trauma often involves concomitant injury to the eye and orbit. These injuries may have devastating consequences to vision, ocular motility, and cosmesis. CT imaging provides a rapid and detailed evaluation of bony structures and soft tissues of the orbit, is sensitive in detection of orbital foreign bodies, and often guides clinical and surgical management decisions in orbital trauma. For this reason, radiologists should be prepared to rapidly recognize common orbital fracture patterns, accurately describe soft tissue injuries of the orbit, detect and localize retained foreign bodies within the globe and orbit, and recognize abnormalities of the contents and integrity of the globe. In this review, we present a systematic approach to assist radiologists in the rapid evaluation of orbital trauma using the "BALPINE" mnemonic-bones, anterior chamber, lens, posterior globe structures, intraconal orbit, neurovascular structures, and extraocular muscles/extraconal orbit. Using this approach, we describe common traumatic findings within each of these spaces, and present common postsurgical appearances that can mimic findings of acute trauma.

Orbital fractures: role of imaging

The orbit may be injured directly or indirectly. Blunt and penetrating trauma occurs with equal frequency. Soft tissue swelling often obscures direct clinical evaluation of the globe, limits ocular motion, and may limit clinical assessment of vision. Plain film radiographs of the orbits and sinuses are rarely used for diagnosis in orbital trauma. Computed tomography is considered the imaging modality of choice in this circumstance, as it is deemed to be the most accurate method in detecting fractures. The protocol is based on obtaining thin-section axial scans and multiplanar reformatted images, both are useful tools to guide treatment. Orbital fractures are not considered an ophthalmologic emergency unless there is visual impairment or globe injury. Surgical repair is indicated for patients who have persistent diplopia or cosmetic concerns (enophthalmos) and generaly is not performed until swelling subsides 7-10 days after injury.

Globe trauma

In the United States, it is estimated that 3% of all emergency room visits are the result of eye injury, with many seen in combination with other orbital injuries. These often result from motor vehicle accidents and sports-related injuries. Clinical ophthalmologic examination is the key to rapid and accurate diagnosis of most ocular injuries. Imaging, in combination with the ophthalmologic examination, can be a powerful tool in the evaluation of traumatic injury to the globe. We review the roles of computed tomography, magnetic resonance imaging, and ultrasound in the evaluation of these patients and illustrate common and uncommon traumatic ocular pathology.

Accuracy of linear measurements from cone-beam computed tomography-derived surface models of different voxel sizes

INTRODUCTION

The aims of this study were to determine the linear accuracy of 3-dimensional surface models derived from a commercially available cone-beam computed tomography (CBCT) dental imaging system and volumetric rendering software and to investigate the influence of voxel resolution on the linear accuracy of CBCT surface models.

METHODS

Glass sphere markers were fixed on 10 dry mandibles. The mandibles were scanned with 0.40 and 0.25 voxel size resolutions in 3 sessions. Anatomic truth was established with 6 direct digital caliper measurements. The surface models were rendered by a volumetric rendering program, and the CBCT measurements were established as the mean of the 3 measurements.

RESULTS

The intraclass correlation coefficients between the physical measurements and the measurements of the CBCT images of 0.40 and 0.25 voxels were all more than 0.99. All CBCT measurements were accurate. There was no difference between the accuracy of the measurements between the 0.40 and 0.25 voxel size groups. The smallest detectable differences of the CBCT measurements were minimal, confirming the accuracy of the CBCT measurement procedure.

CONCLUSIONS

The measurements on 3-dimensional surface models of 0.25 and 0.40 voxel size data sets made with the 3D eXam CBCT scanner (KaVo Dental GmbH, Bismarckring, Germany) and SimPlant Ortho Pro software (version 2.00, Materialise Dental, Leuven, Belgium) are accurate compared with direct caliper measurements. An increased voxel resolution did not result in greater accuracy of the surface model measurments.

Late occurrence of lens particle glaucoma due to an occult glass intralenticular foreign body

We report a case of traumatic mature cataract with a late occurrence of lens particle glaucoma after 11 years of trauma due to a presence of an occult intralenticular glass foreign body which was detected accidentally during the cataract surgery.

Imaging of orbital trauma

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. Common posttraumatic orbital injuries include anterior chamber injuries, injuries to the lens, open-globe injuries, ocular detachments, intraorbital foreign bodies, carotid cavernous fistula, and optic nerve injuries. Radiographic examination of the orbits is rarely performed. Ultrasonography (US) can be very useful for evaluating the globe and its contents; however, US is contraindicated if a ruptured globe is suspected. Magnetic resonance imaging may be difficult to perform emergently; it is contraindicated if there is a possibility that a metallic intraorbital foreign body is present. Computed tomography (CT) is considered to be the top choice for evaluating orbital trauma. The best protocol is to obtain thin-section axial CT scans, then to perform multiplanar reformation. When evaluating a patient with an orbital injury, the radiologist should do the following: (a) evaluate the bony orbit for fractures, note any herniations of orbital contents, and pay particular attention to the orbital apex; (b) evaluate the anterior chamber; (c) evaluate the position of the lens (the lens may be displaced, and it may be either completely or partially dislocated); (d) evaluate the posterior segment of the globe, look for bleeds or abnormal fluid collections, and evaluate for radiopaque or radiolucent foreign bodies; and (e) evaluate the ophthalmic veins and the optic nerve complex, especially the orbital apex.

What's in your mouth? The CT appearance of comestible intraoral foreign bodies

BACKGROUND AND PURPOSE

Comestible or chewable intraoral foreign bodies (IOFB), such as candies, gum, and chewing tobacco, are seen incidentally on many CT scans of the head and neck. If these foreign bodies are misinterpreted as pathology, patients may be subjected to unnecessary distress or unneeded radiation from additional imaging. The purpose of this study was to characterize the CT appearance of comestible IOFBs and to find characteristics that distinguish them from true pathology.

MATERIALS AND METHODS

With institutional review board approval, 30 patients who were already scheduled to undergo CT examinations of the head and neck were enrolled in this study. Nine typical IOFBs with different physical characteristics were selected for inclusion. Each patient placed 1 IOFB in his or her mouth before the initiation of the routine clinical scan. The resulting scans were evaluated by 2 head and neck radiologists. In vivo and ex vivo attenuation measurements were obtained for each IOFB.

RESULTS

The attenuation of comestible IOFBs ranged from 184 to 475 Hounsfield units. Large, hard IOFBs were most easily distinguished from mucosal lesions, but might be mistaken for odontogenic or bone tumors. Small, hard IOFBs could be mistaken for calculi, tooth fragments, or enhancing vessels. Soft IOFBs generally had more confusing configurations and more heterogeneous densities and, thus, might be mistaken for enhancing mucosal lesions. Foci of gas were often identified within chewable IOFBs, mimicking an abscess. Because all of the IOFBs had higher densities than soft tissue, they could all be mistaken for calcified, enhancing, or bony lesions.

CONCLUSION

Radiologists frequently encounter IOFBs on CT examinations of the head and neck. Familiarity with the expected appearance of these incidental pseudolesions is important to prevent misdiagnosis as a true pathologic process.

Detection of ingested cocaine-filled packets—Diagnostic value of unenhanced CT

PURPOSE

Emergency departments are facing nowadays an increasing number of illegal drug-related health problems, associated with medicolegal and/or social consequences. Body stuffers are street cocaine dealers, who either store wrapped packets of drugs in their rectum or hastily swallow them, prompted by fear of police's arrest. These packets can be life threatening in case of leakage. We evaluate the diagnostic value of unenhanced multidetector CT (MDCT) for detection of cocaine-filled packets (CFP) ingested by body stuffers in a phantom model.

MATERIALS AND METHODS

Our phantom simulated normal bowel contents in which a varying number of true and false CFP were randomly mixed. Both only differ in radiological density. During 18 different reading sessions, four radiologists independently evaluated the presence and number of true and false CFP. Interobserver agreement, sensitivity, specificity, positive and negative predictive value were calculated.

RESULTS

Interobserver agreement for detection of any packets, for visualization of true, and false CFP was good (kappa=0.63, 0.74 and 0.58, respectively). Sensitivity, specificity, positive and negative predictive value for detection of any packets was 95.6%, 100%, 100% and 62.5%, respectively; for visualization of the true CFP 86.5%, 100%, 100% and 77.6%, respectively; and for the false packets 98.1%, 65%, 88.6% and 87.5%, respectively.

CONCLUSION

Unenhanced MDCT without bowel preparation is a fast, reliable and easily reproducible imaging modality for the immediate detection of ingested CFP, thus facilitating medicolegal management of body stuffers.

Intralenticular intraocular foreign body after stone impact: CT and US findings

INTRODUCTION

Intraocular foreign body (IOFB) is a relatively common entity in emergency departments worldwide. Appropriate ocular assessment is mandatory if an intraocular foreign body is suspected because it is associated with an increased risk of endophtalmitis and a wide range of complications including hyphaema, cataract, vitreous hemorrhage, and retinal tears and detachment.

CASE REPORT

We present a case of intralenticular intraocular foreign body after stone impact.

DISCUSSION

Ultrasonography (US) and computed tomography (CT) show an accurate location of the foreign body inside the lens. This finding enabled the surgeon to perform a phacoemulsification lens extraction with removal of the foreign body, the optimal method of removing intralenticular IOFB. To our knowledge, this is the first US and CT imaging report.

The assessment of ocular injury by ultrasound

Ocular trauma is readily investigated by ultrasound, which is of particular value when the light conducting media are opacified by haemorrhage or other injury. In this situation, direct visualization of the ocular contents by ophthalmoscopy is difficult or impossible. Severe complications are treated by microsurgical techniques, and ultrasound evaluation represents the only practicable method of examination for surgical planning. This review illustrates the grey-scale (B scan or two-dimensional) features of the traumatized eye and describes the examination technique.

Diagnostic value of computed tomography in dogs with chronic nasal disease

Computed tomographic (CT) studies of 80 dogs with chronic nasal disease (nasal neoplasia (n = 19), nasal aspergillosis (n = 46), nonspecific rhinitis (n = 11), and foreign body rhinitis (n = 4)) were reviewed retrospectively by two independent observers. Each observer filled out a custom-designed list to record his or her interpretation of the CT signs and selected a diagnosis. Accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the diagnosis of each disease. The agreement between observers was evaluated. The CT signs corresponded to those previously described in the literature. CT had an accuracy greater than 90% for each observer in all disease processes. The sensitivity, specificity, PPV, and NPV were greater than 80% in all dogs with the exception of the PPV of foreign body rhinitis (80% for observer A and 44% for observer B). There was a substantial, to almost perfect, agreement between the two observers regarding the CT signs and diagnosis. This study indicates a high accuracy of CT for diagnosis of dogs with chronic nasal disease. The differentiation between nasal aspergillosis restricted to the nasal passages and foreign body rhinitis may be difficult when the foreign body is not visible.

Orbital trauma

Assessment of the orbit for orbital trauma is best achieved expeditiously with CT in the determination of extent of injury and the presence of foreign body. MR imaging has a limited role but is valuable in examining the optic nerve and globe for injury and has proven to be an adjunct modality in the assessment of orbital injury.