Acute ocular pain during magnetic resonance imaging due to retained intraocular metallic foreign body: the role of ultrasonography and ultrasound biomicroscopy in diagnosis and management of this condition

Intraocular foreign bodies in children: A retrospective case series

INTRODUCTION

Open globe injuries are a major cause of visual impairment in children, related to the severity of the trauma or secondary to induced amblyopia. Intraocular foreign bodies (IOFB) have been reported in approximately one third of cases of open globe injuries. As clinical presentation and management may differ between adults and children, data is lacking about IOFBs in children under 18years of age. The purpose of this study was to assess the clinical characteristics and visual prognosis of ocular trauma associated with intraocular foreign bodies in children.

MATERIALS AND METHODS

This single-center retrospective study included patients under 18years of age treated for ocular trauma with IOFB. Demographic characteristics, complete initial and final ophthalmological examination, imaging data and details of medical and surgical management were collected.

RESULTS

Fourteen patients were included (78.6% boys), with a mean age of 10.3years (min 7months-max 17years). In 92.9% of cases, patients were found to have a single IOFB, mostly metallic (71.4%). Posterior segment IOFBs were found in 50% of cases, anterior segment IOFBs in 28.6% and orbital IOFBs in 21.4%. The clinical examination permitted detection of the IOFBs in 50% of cases, while they were visible on CT scan in all cases. The mean initial visual acuity was 20/320, and the mean final visual acuity was 20/125. Endophthalmitis occurred in 2 cases (14%).

DISCUSSION

Open globe injuries associated with IOFB are severe and sight-threatening. Localization of the IOFB in the posterior segment has a worse prognosis. CT scan is mandatory, especially in children, as the trauma history is often missing. Retinal detachment and endophthalmitis appear to be the main prognostic factors requiring urgent specialized pediatric ophthalmology management.

Efficiency of different imaging methods in detecting ocular foreign bodies

BACKGROUND

Ocular foreign bodies (OFBs) are a relatively common occurrence in ocular injuries, and a severe risk factor for vision disorders. They are notoriously challenging to identify and localize precisely to allow surgical removal, even with the most recent technological advancements.

PURPOSE

To compare the efficiency of different imaging methods in detecting and localizing OFBs.

METHODS

We conducted a retrospective analysis of the medical records of patients with OFBs, detected by ultrasound biomicroscopy (UBM) and confirmed during surgery. Patients who presented to our medical center between January 2016 and January 2022 and also underwent computed tomography (CT), X ray, and/or ocular B-scan ultrasonography (B-scans) were selected.

RESULTS

This study included 134 patients with a history of ocular trauma and OFBs (mean age: 47.25 years, range: 8-78). The mean time interval from injury to UBM examination was 36.31 months (range: 0.2-120 months). Most OFBs were metallic (51.82%) or plant-based (25.37%); 22.39% of them were located in the sclera, 26.87% in the anterior chamber, and 23.88% in the ciliary body and iris. OFBs ranged in size from 0.10 to 6.67 mm (mean: 1.15 ± 1.10 mm). B-scans identified OFBs in 37 of the 119 patients examined (31.09%); CT in 52 of 84 patients (61.90%); and radiography in 29 of 50 patients (58.00%). Univariate and multivariate analyses determined that both CT and radiography showed low detection rates for plant-based versus non-plant-based OFBs (CT: p < 0.001; radiography: p = 0.007), small particles (<1.00 mm vs. >1.00 mm; CT: p = 0.001, radiography: p = 0.024), and with eyeball wall locations (vs. intraocular; CT: p < 0.001, radiography: p = 0.021). Similarly, B-scans were less efficient for plant-based and eyeball wall-located OFBs (both p = 0.001), whereas the difference based on dimensions was not significant (p = 0.118).

CONCLUSIONS

CT, radiography, and B-scans showed lower detection rates for plant-based, small, and eyeball wall-located OFBs. Our findings strongly suggest that UBM could be a more adequate imaging modality when such OFBs are suspected.

ULTRASOUND BIOMICROSCOPY AND ECHOGENIC EXTERNAL MARKER ASSISTED INTRAOCULAR FOREIGN BODY REMOVAL

PURPOSE

We report a novel method of intraoperative localization of a retained anterior intraocular foreign body (IOFB), using a combination of ultrasound biomicrosopy and an insulated needle.

METHODS

A retrospective case report of a 56-year-old man who presented with a right eye IOFB.

RESULTS

On presentation, vision was decreased in the right eye to count fingers with a small subconjunctival hemorrhage, but no other signs of a penetrating laceration. Orbital CT revealed an IOFB, and the initial vitrectomy failed to retrieve the IOFB. Then, during the subsequent vitrectomy, using an ultrasound compatible needle and an ultrasound biomicrosopy, we were able to precisely locate and remove the small anterior IOFB.

CONCLUSION

Retained IOFBs can lead to severe irreversible vision loss if not promptly removed. Ancillary imaging modalities and localization techniques can help locate occult IOFBs in difficult cases.

Management of intrascleral chestnut burr spines under ultrasound biomicroscopy guidance

Purpose

To explore the efficacy of ultrasound biomicroscopy (UBM) as a tool for detecting and localizing intrascleral chestnut burr spines.

Methods

Individuals who were diagnosed with definitive or suspected intrascleral chestnut burr injuries between 2019 and 2020 were retrospectively reviewed. All patients underwent UBM to detect potential intrascleral spines. UBM imaging features were recorded and analyzed. Intrascleral spines were removed based upon UBM-guided localization. Patient clinical profiles, management, and treatment outcomes were recorded.

Results

A total of 10 eyes (10 patients; 6 males, 4 females) were diagnosed with intrascleral spines over the study period, with an average patient age of 55 years (range: 39-71). Three of these 10 eyes exhibited involvement of the palpebrae and cornea, whereas three exhibited corneal involvement, and the remaining four patients exhibited only intrascleral spine injuries owing to their having undergone previous intracorneal spine extraction procedures. UBM features consistent with chestnut burr spines manifest a hyperechoic spot with a shadow. UBM enabled the precise localization of these spines and thus ensured their successful removal via a single surgery. During follow-up, two patients experienced vitreous hemorrhage due to a penetrating injury into the ciliary body that was gradually absorbed. All patients with eye irritation and red eyes progressed favorably, and no surgical complications were recorded.

Conclusion

A retained scleral chestnut burr spine should be suspected if a patient complains of persistent eye irritation following intracorneal spine removal. UBM may be a valuable tool for detecting spines retained in the sclera, enabling the successful removal thereof.

Value of Ocular Endoscopy in Extraction of Intraocular Foreign Bodies of Cilia in Patients with Open Ocular Trauma

BACKGROUND The aim of this study was to analyze the value of ocular endoscopy in detecting and extracting intraocular cilia in patients with ocular trauma. MATERIAL AND METHODS We retrospectively analyzed data on identification and extraction of 46 intraocular cilia in 16 eyes with open-globe injury during endoscope-assisted vitrectomy. RESULTS A total of the 16 patients with open-globe injury were operated on from September 2002 to June 2019. The cornea in 14 eyes was cloudy. Two eyes had endophthalmitis and 13 eyes had retinal detachment. A total of 46 cilia were extracted through direct observation under the ocular endoscope during vitrectomy 1 to 68 weeks after injury. The number of cilia per eye varied from 1 to 10. Most of the cilia were located in or near the wound. Postoperative IOP was normal in 14 patients. The follow-up after surgery showed hypotony in only 2 eyes (7.2 and 5.8 mmHg, respectively). Compared with preoperative intraocular pressure, there was a statistically significant difference. The postoperative visual acuity improved in 12 eyes and remained unchanged in 3 eyes. The vision after surgery was significantly improved compared with that before surgery (P=0.006). The intraocular pressure increased significantly after operation (P<0.001). And no glaucoma or retinal detachment or endophthalmitis was found. No eyes needed additional vitreous surgery. CONCLUSIONS Ocular endoscopy allows surgeons to detect intraocular cilia that were no undetected by CT or B-ultrasound preoperatively in time and to extract them effectively. It improves performance of vitrectomy in the presence of a cloudy cornea and also prevents exogenous endophthalmitis. The vision of patients with ocular trauma was improved.

Diagnostic Accuracy of Ultrasonography for Rotator Cuff Tears: A Systematic Review and Meta-analysis

Background

With recent improvements in transducer strength, image resolution, and operator training, ultrasound (US) provides an excellent alternative imaging modality for the diagnosis of rotator cuff tears.

Purpose

To evaluate the diagnostic accuracy of US for partial- and full-thickness rotator cuff tears and biceps tendon tears, compare diagnostic values with those of magnetic resonance imaging (MRI) using arthroscopy as the reference standard, assess longitudinal improvements in accuracy, and compare diagnostic values from operators with different training backgrounds.

Study Design

Systematic review; Level of evidence, 3.

Methods

The PubMed and Cochrane Library databases were systematically searched for full-text journal articles published between January 1, 2010, and April 1, 2020. The inclusion criteria were studies that evaluated the diagnostic accuracy of US for rotator cuff tears or biceps tendon tears utilizing arthroscopy as the reference standard. The exclusion criteria were studies with <10 patients, studies including massive tears without reporting diagnostic data for specific tendons, and studies lacking diagnostic outcome data. Extracted outcomes included diagnostic accuracy, sensitivity, specificity, negative predictive value, and positive predictive value. The mean difference and 95% confidence interval were calculated for both US and MRI diagnostic values, and meta-analysis was conducted using the Mantel-Haenszel random-effects model.

Results

In total, 23 eligible studies involving 2054 shoulders were included. US demonstrated a higher median diagnostic accuracy for supraspinatus tendon tears (0.83) and biceps tendon tears (0.93) as compared with subscapularis tendon tears (0.76). US was found to have a higher median accuracy (0.93) for full-thickness supraspinatus tears than partial-thickness tears (0.81). US had superior median sensitivity for partial-thickness supraspinatus tears when performed by radiologists as opposed to surgeons (0.86 vs 0.57). Meta-analysis of the 5 studies comparing US and MRI demonstrated no statistically significant difference in diagnostic sensitivity, specificity, or accuracy for any thickness supraspinatus tears (P = .31-.55), full-thickness tears (P = .63-.97), or partial-thickness tears (P = .13-.81).

Conclusion

For experienced operators, US is a highly sensitive and specific diagnostic modality for the diagnosis of supraspinatus tears and demonstrates statistically equivalent capability to MRI in the diagnosis of both full- and partial-thickness rotator cuff tears.

A narrative review of current and emerging MRI safety issues: What every MRI technologist (radiographer) needs to know

Magnetic resonance imaging (MRI) has been traditionally regarded as a safe imaging modality due to the absence of ionising radiation. However, MRI is a source of potential hazards with a variety of risks including, but not limited to, those associated with the various electromagnetic fields used for imaging. All MRI technologists (radiographers) require sound knowledge of the physical principles of the MRI scanner and must understand the associated safety risks and how to avoid adverse events from occurring. MRI technologists now assume more responsibility in clinical decision‐making, and their knowledge base has consequently had to expand significantly. In addition, rapid advancements in MRI technology and other correlated areas such as medical implant technology, and the associated increase in MRI safety issues, place increasing demands on the MRI technologist to constantly keep abreast of current and future developments. This article reviews current and emerging MRI safety issues relevant to the three MRI electromagnetic fields and highlights the key information that all MRI technologists should be fully cognisant of to ensure competent and safe practice within the MRI environment.

Gastric Perforation During MRI After Ingestion of Ferromagnetic Foreign Bodies

CASE PRESENTATION

A 65-year-old male with schizophrenia and intellectual disability ingested what was reported to be two AA batteries, prior to a scheduled magnetic resonance imaging (MRI) study. He developed severe abdominal pain and presented to the emergency department the following day with hypovolemic/septic shock. General surgery retrieved two metal sockets and a clevis pin from the stomach prior to surgical repair of a gastric perforation. This case highlights a rare yet critical outcome of ingesting ferromagnetic foreign bodies prior to an MRI study.

DISCUSSION

Medical literature on this subject is scarce as indwelling metal foreign bodies are a contraindication to obtaining an MRI. Yet some patients with indwelling metallic foreign bodies proceed with MRI studies due to either challenges in communication such as age, psychiatric/mental debility, or unknowingly having an indwelling metal foreign body. In this case, the patient surreptitiously ingested metal objects prior to obtaining an MRI.

What Radiologist Should Know about MRI Translational Forces and Hazard: An Ex-Vivo Simulation of Retained Metallic Shrapnel

Background

In a country immersed in endless rounds of wars, retained metallic foreign bodies remain a significant dilemma in the daily practice of every Lebanese radiologist. When a shrapnel's hazard is of concern, the decision between performing or refusing a justified MRI exam is not always straightforward. In this small trial, we aimed to better understand the shrapnel's MRI safety by mimicking our daily practice.

Methods

Five shrapnel with an incremental increase in their long axis were put in an animal flesh and then introduced into a 3 T magnetic field. The behavior of each shrapnel was concretely assessed by performing before and after magnetic field exposure CT acquisitions.

Results

Translation along the z-axis ranged from 0.9 mm to 2.8 mm. Torque angle ranged between 2.8 and 54 degrees with an average of 15.62 degrees.

Conclusions

Shrapnel's movements in the magnetic field are not negligible during the acute phase of injury where there is no reinforcing fibroblastic reaction and invite us to reconsider the MRI safety of these metallic foreign bodies. Standard radiographs may be sufficient, but a targeted CT scan may be of better value for a confident decision for assessment of shrapnel position near viscera and major vessels.

The ABCs of Ocular Trauma: Adapting a Familiar Mnemonic for Rapid Eye Exam in the Pre-Ophthalmic Zone of Care

Evaluation and management of eye trauma is daunting to many practitioners. For general medical emergencies, the familiar ABCs mnemonic serves to both recompose the provider as well as provide a logical order for evaluation and action. We recently adapted an ABCs mnemonic to provide non-ophthalmologists with a familiar method for systematically evaluating and managing eye trauma. A = ACUITY. Visual acuity is the most importance piece of information in eye trauma. B = BEST exam of BOTH eyes. Starting with acuity, examination proceeds from the front to the rear of the eye. Examine the uninjured eye first. C = CONTIGUOUS STRUCTURES and CONTACT LENSES. Examine structures contiguous to the apparent injury. Inspect for contact lens wear. D = DRUGS, DIAGNOSTIC IMAGING, and the DON’TS. Start antibiotics, antiemetics, and analgesics. Administer tetanus. Obtain computerized tomography if available. Do not attempt ocular ultrasound or magnetic resonance imaging. Do not apply pressure to the eye. Do not patch the eye or apply any medication. E = EYE SHIELD and EVACUATE. Shield and ship to ophthalmology. The mnemonic was adapted to reflect current Joint Trauma Services and Tactical Combat Casualty Care practice guidelines. We believe this familiar mnemonic will serve as a useful tool in allowing non-ophthalmologists to comfortably and safely evaluate an eye for trauma.

A Patient with an Inert Intraocular Foreign Body

A 29-year-old man was brought to the hospital for treatment after an alleged workplace accident. Initial assessment revealed only mild chest injury and mild confusion, with no other injury. His vision was unaffected with no relative afferent pupillary defect. A computed tomography scan of the brain, performed to rule out brain injury, revealed an incidental finding of a foreign body in the left intravitreal cavity with no other significant findings. Further examination of his medical history revealed that he had experienced a trauma one year earlier, in which his left eye was pierced by a projectile. Immediately post-trauma, his vision had been reduced significantly, but improved over the next few weeks without medical treatment. The current examination of his left eye revealed a small hyperpigmented area on the sclera, representing the point of entry of his previous wound. An encapsulated foreign body was observed in the inferior intravitreal cavity, surrounded by retinal atrophy, and a normal posterior pole. He was managed conservatively without complications. The decision to remove a missed retained intraocular foreign body is complex and depends on multiple factors, including surgical difficulty and the composition, size, and location of the retained foreign body. Removal should be weighed against the possible serious complications of intraocular surgery. If removal is surgically difficult, or the retained material is inert, patients can be managed conservatively with regular monitoring.