MAGNETIC RESONANCE IMAGING AND COMPUTED TOMOGRAPHY FOR THE DETECTION AND CHARACTERIZATION OF NONMETALLIC INTRAOCULAR FOREIGN BODIES

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.

Demystifying the role of magnetic resonance in identifying intraocular foreign bodies: a case of ocular siderosis

BACKGROUND

Ocular siderosis (OS) is a significant cause of visual loss due to retained ferrous intraocular foreign bodies (IOFB). Despite its rarity, OS can lead to severe visual impairment if not promptly diagnosed and treated. This case is notable due to the occult nature of the IOFB, which was undetected by standard imaging modalities, emphasizing the critical role of magnetic resonance imaging (MRI) in such scenarios.

CASE PRESENTATION

A 51-year-old Caucasian male presented with progressive vision loss in his right eye over 20 days. Best corrected visual acuity (BCVA) was 20/1000 in the right eye and 20/20 in the left eye. Intraocular pressure (IOP) was 9 mmHg in both eyes. Slit-lamp examination revealed a small linear corneal wound and an iris defect in the right eye, along with a cataract featuring brownish deposits on the anterior capsule. The left eye was normal. Fundus examination of the right eye was hindered by media opacities. Ultrasonography showed a flat retina and choroid with no detectable IOFB. Despite a strong clinical suspicion of OS, computed tomography (CT) did not detect any IOFB. MRI subsequently identified an artifact in the inferior sectors of the right eye, indicative of a metallic IOFB. Surgical intervention involved a 23-gauge vitrectomy, phacoemulsification, IOFB removal and silicon oil (SO) tamponade resulting in a fully restored VA of 20/20 and normal IOP one month post-operation. SO was removed 2 months later. The retina remained adherent with no PVR development, and optical coherence tomography (OCT) scans showed a normal macula.

CONCLUSIONS

This case underscores the importance of considering OS in patients with unexplained vision loss and history of ocular trauma, even when initial imaging fails to detect an IOFB. MRI proved crucial in identifying the IOFB, highlighting its value in the diagnostic process. Early detection and surgical removal of IOFBs are essential to prevent irreversible visual damage. This case demonstrates that MRI should be employed when CT and ultrasonography are inconclusive, ensuring accurate diagnosis and timely intervention to preserve vision.

Computed Tomography Diagnostic Abilities for Open-Globe Injuries in Pediatric Versus Adult Patients

OBJECTIVES

The aim of this study was to compare the role of computed tomography (CT) in the diagnosis of open-globe trauma and intraocular foreign body (IOFB) in pediatric and adult age groups.

METHODS

Medical records of cases with open-globe trauma at Inonu University Hospital's Ophthalmology Emergency Service were retrospectively evaluated. Preoperative orbital CT images of the cases obtained at emergency services and their clinical and/or surgical findings were compared in pediatric and adult groups.

RESULTS

We included 47 eyes of 47 cases aged 18 years and below (pediatric group) and 85 eyes of 82 cases over 18 years (adult group). The mean ± SD age was 10.80 ± 5.11 years (range, 2-18 years) in the pediatric group and 46.34 ± 19.01 years (range, 19-82 years) in the adult group. Computed tomography images revealed 21.7% of the cases with corneal lacerations, 55.5% with scleral lacerations, and 91.6% with corneoscleral lacerations in the pediatric group, whereas the respective numbers were 48.4%, 66.6%, and 61.9% in the adult group. The detection rates of corneal penetrations and vitreous hemorrhage with CT were significantly lower in the pediatric group than in the adult group (P < 0.05). The CT scans diagnosed 66.6% of the pediatric cases and 90% of the adult cases with an IOFB.

CONCLUSIONS

Corneal lacerations and IOFBs can be missed, especially in the pediatric group, because the eye is smaller in adults. Pediatric patients with a history of ocular trauma should undergo an examination under general anesthesia followed by surgical exploration if necessary.

Detectability of foreign body materials using X-ray, computed tomography and magnetic resonance imaging: A phantom study

PURPOSE

To evaluate the effectiveness of plain radiography (X-ray. XR), computed tomography (CT) and magnetic resonance imaging (MR) in visualising commonly seen foreign bodies. A special focus was put on objects relevant to head and neck surgery.

METHOD

Thirty-four commonly encountered objects of different compositions including wood, plastic, and glass were embedded in a gelatin gel phantom and imaged using XR, CT and MR. The success rates of radiologists in detecting and correctly identifying the foreign objects were evaluated. Subjective visibility was rated on a 4-point Likert scale. Objective visibility was analysed using region of interest-based contrast for CT.

RESULTS

Sensitivity in foreign bodies detection was highest in MR (97.1 %) followed by CT (86.0 %) and x-ray (61.8 %). Success rates for the correct identification of the objects and material types were highest in MR (33.3 % and 39.2 %, respectively) followed by CT (25.5 % for both) and XR (16.7 % and 15.7 %). Overall, subjective visibility was rated higher in CT and MR imaging ("good visibility"), as compared to XR ("poor visibility"). Interreader agreement was high across modalities (Kendall's W = 0.935, 0.834 and 0.794 for XR, MR and CT, respectively).

CONCLUSIONS

Detection and identification of non-ferromagnetic objects was most successful in MR followed by CT imaging in this experimental setup.

Ocular siderosis: a misdiagnosed cause of visual loss due to ferrous intraocular foreign bodies-epidemiology, pathogenesis, clinical signs, imaging and available treatment options

Purpose

The purpose of this paper is to provide a meaningful literature review about the epidemiology, pathogenesis, clinical signs, imaging and treatment of ocular siderosis (OS).

Methods

A computerized search from inception up to March 2020 of the online electronic database PubMed was performed using the following search strings: “ocular siderosis” and “siderosis bulbi”. The reference list in each article was analysed for additional relevant publications.

Results

OS is an uncommon cause of visual loss due to a retained ferrous intraocular foreign body (IOFB). It may develop from 18 days to years after a penetrating trauma that usually occurs during hammering. On average, patients are 22–25 years old, and the vast majority are male. The most common cause of OS development is delayed presentation by the patient or missed diagnosis of IOFB after trauma. The pathophysiology is not fully understood; nevertheless, iron deposition causes hydroxyl radical formation, which damages photoreceptors and retinal pigment epithelium. Moreover, iron damages retinal vessels with consequent inner retinal layers degeneration. The most frequent signs are iris heterochromia, pupillary mydriasis, cataract development and retinal arteriolar narrowing with pigmentary retinal degeneration. Electroretinogram signs, in particular, b-wave amplitude reduction, arise earlier than clinical signs. Orbital CT scans and ultrasonography play an essential role in detecting IOFBs. Treatment depends on the IOFB location and OS development. However, it is crucial to remove the IOFB after OS development because visual acuity and clinical signs may improve. Anterior segment IOFBs can be dislodged using an intraocular magnet (IOM) or forceps through limbal paracentesis. In contrast, posterior segment IOFBs require a pars plana vitrectomy and IOM or forceps to be removed through an enlarged sclerotomy or the limbus.

Conclusion

Recommending the usage of protective glasses and spreading knowledge about OS may further benefit patient care.

Intraorbital Graphite Foreign Body With a Delayed Presentation of Optic Neuropathy

Traumatic penetrating injuries to the orbit from pencils, while uncommon, have a plethora of presentations, both acute and delayed. With the most incidents occurring in the pediatric population where obtaining a detailed history is difficult, the ability to effectively evaluate and diagnose these injuries is cumbersome, yet important. The authors report a patient who presented with optic neuropathy, blepharoptosis, and strabismus 10 months after an orbital injury with pencil graphite.

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.

The role of computed tomography in the immediate workup of open globe injury

PURPOSE

Immediate primary closure is indicated in cases of traumatic open globe injury. Orbital computed tomography (CT) is performed prior to primary closure in order to rule out possible intraocular foreign bodies (IOFB) and/or damage to adjacent extraocular as well as intraocular structures. The aim of the present study is to evaluate the yield of orbital CT scan in immediate clinical decision-making in cases of open globe injury.

METHODS

All cases of open globe injury treated in our institute during a 10-year period were reviewed. All underwent a CT scan before any surgical intervention, regardless of trauma severity. The influence of the CT scan results on decisions regarding the immediate treatment of the open globe injury was analyzed.

RESULTS

A total of 125 cases of open globe injury were included in the present study. In none of these cases did the CT scan results have any influence on immediate treatment. The CT scan results did influence decisions that were made after the immediate operative stage.

CONCLUSIONS

Computed tomography scan has limited value in immediate clinical decision-making in cases of open globe injury scheduled for primary closure. While not crucial prior to the initial procedure, it is of value in managing the case during the following few days as well as later on. This study suggests that a CT scan performed after the initial globe exploration and suturing procedure is a valid alternative to stalling the definite globe suturing process until a CT scan is obtained and interpreted.

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.

Endophthalmitis: state of the art

Endophthalmitis is an uncommon diagnosis but can have devastating visual outcomes. Endophthalmitis may be endogenous or exogenous. Exogenous endophthalmitis is caused by introduction of pathogens through mechanisms such as ocular surgery, open-globe trauma, and intravitreal injections. Endogenous endophthalmitis occurs as a result of hematogenous spread of bacteria or fungi into the eye. These categories of endophthalmitis have different risk factors and causative pathogens, and thus require different diagnostic, prevention, and treatment strategies. Novel diagnostic techniques such as real-time polymerase chain reaction (RT-PCR) have been reported to provide improved diagnostic results over traditional culture techniques and may have a more expanded role in the future. While the role of povidone-iodine in prophylaxis of postoperative endophthalmitis is established, there remains controversy with regard to the effectiveness of other measures, including prophylactic antibiotics. The Endophthalmitis Vitrectomy Study (EVS) has provided us with valuable treatment guidelines. However, these guidelines cannot be directly applied to all categories of endophthalmitis, highlighting the need for continued research into attaining improved treatment outcomes.