Safety Considerations for Diagnostic Ultrasound in the Eye

Pediatric orbital lesions: ocular pathologies

Orbital pathologies can be broadly classified as ocular, extra-ocular soft-tissue (non-neoplastic and neoplastic), osseous, and traumatic. In part 1 of this orbital series, the authors will discuss the differential diagnosis and key imaging features of pediatric ocular pathologies. These include congenital and developmental lesions (microphthalmos, anophthalmos, persistent fetal vasculature, coloboma, morning glory disc anomaly, retinopathy of prematurity, Coats disease), optic disc drusen, infective and inflammatory lesions (uveitis, toxocariasis, toxoplasmosis), and ocular neoplasms (retinoblastoma, retinal hamartoma, choroidal melanoma, choroidal nevus). This pictorial review provides a practical approach to the imaging work-up of these anomalies with a focus on ocular US as the first imaging modality and additional use of CT and/or MRI for the evaluation of intracranial abnormalities. The characteristic imaging features of the non-neoplastic mimics of retinoblastoma, such as persistent fetal vasculature and Coats disease, are also highlighted.

Pediatric orbital lesions: neoplastic extraocular soft-tissue lesions

Pediatric neoplastic extraocular soft-tissue lesions in the orbit are uncommon. Early multimodality imaging work-up and recognition of the key imaging features of these lesions allow narrowing of the differential diagnoses in order to direct timely management. In this paper, the authors present a multimodality approach to the imaging work-up of these lesions and highlight the use of ocular ultrasound as a first imaging modality where appropriate. We will discuss vascular neoplasms (congenital hemangioma, infantile hemangioma), optic nerve lesions (meningioma, optic nerve glioma), and other neoplastic lesions (plexiform neurofibroma, teratoma, chloroma, rhabdomyosarcoma, infantile fibrosarcoma, schwannoma).

Pediatric orbital lesions: non-neoplastic extraocular soft-tissue lesions

Orbital pathologies can be broadly classified as ocular, extraocular soft-tissue (non-neoplastic and neoplastic), osseous, and traumatic. In this paper, we discuss the key imaging features and differential diagnoses of congenital and developmental lesions (dermoid cyst, dermolipoma), infective and inflammatory pathologies (pre-septal cellulitis, orbital cellulitis, optic neuritis, chalazion, thyroid ophthalmopathy, orbital pseudotumor), and non-neoplastic vascular anomalies (venous malformation, lymphatic malformation, carotid-cavernous fistula), emphasizing the key role of CT and MRI in the imaging work-up. In addition, we highlight the adjunctive role of ocular ultrasound in the diagnosis of dermoid cyst and chalazion, and discuss the primary role of ultrasound in the diagnosis of vascular malformations.

Assessing the Usefulness of Ultrasonography for the Diagnosis and Evaluation of Intra-Orbital Lesions in Pediatric Patients: A Retrospective Analysis

OBJECTIVES

To assess the usefulness of ultrasonography in the diagnosis and evaluation of extraocular intra-orbital lesions in pediatric patients.

METHODS

Twenty-three pediatric patients with intra-orbital lesions who underwent both ultrasound and computed tomography/magnetic resonance imaging (CT/MRI) were included. The following parameters were evaluated using ultrasound: 1) lesion detection rate (presence or absence of lesions), 2) lesion characteristics, 3) lesion location (extraconal or intraconal), and 4) the lesion longest linear dimensions, and these were compared using Fisher's exact test and Mann-Whitney U test.

RESULTS

Two lesions could not be detected using ultrasound; in the other 21 cases, the lesion characteristics diagnosed by ultrasound were correct. Diagnostic accuracy of detection and characteristics assessment using ultrasound were 91.3% and 91.3%, respectively. The lesion location was not significantly different between the two groups (intraconal/extraconal in those detected using ultrasound versus those in the absence on ultrasound = 7/14 versus 0/2, P > .999); however, in two cases that were not detected on ultrasound, the lesions were located at extraconal. Lesions that were small in longest linear dimensions on CT/MRI were not detected using ultrasound (the longest linear dimensions in lesions detected using ultrasound versus that in the absence of ultrasound: 29.5 ± 8.2 [range, 13-46] versus 10 and 11 mm, P = .043).

CONCLUSIONS

Ultrasonography proved to be useful for visualizing and evaluating intra-orbital lesions except for lesions that were relatively small in size. Therefore, although ultrasound could not detect lesions located behind bone and bone invasion, it could be used for diagnosing and selecting treatment strategies for intra-orbital lesions.

A comparison of five point-of-care ultrasound devices for use in ophthalmology and facial aesthetics

Introduction

Point-of-care ultrasound is becoming increasingly popular, and we sought to examine its role in evaluating ocular and periocular structures and facial vasculature. With the large number of point-of-care ultrasound devices available, it is difficult to determine which devices may be best suited for ophthalmic and facial aesthetic applications. This study compares five popular handheld point-of-care ultrasound devices to help guide clinicians in choosing the device best suited for their needs.

Methods

We compared five point-of-care ultrasound devices: Butterfly IQ+ (Butterfly, Burlington, MA), L15 (Clarius Mobile Health, Vancouver, British Columbia, Canada), L20 (Clarius Mobile Health, Vancouver, British Columbia, Canada), Lumify (Philips, Amsterdam, Netherlands) and Vscan Air (GE, Boston, MA). Three ophthalmologists obtained the following views on three volunteers: eight arteries, four ocular and periocular structures and areas of filler injections. The image quality of each view was graded on a four-point Likert-type scale. In addition, graders filled out a survey. The data were analysed using analysis of variance tests with the significance level set to p < 0.05.

Results

In terms of overall image quality, the L20 received the highest mean rating, followed by the L15, Vscan Air, Butterfly IQ+ and the Lumify (p < 0.05). With further stratification for structure type, the L20 was ranked first for filler, artery and orbital imaging (p < 0.05).

Conclusions

The L20 received the highest image quality rankings. While image quality is an important aspect of point-of-care ultrasound device selection, other factors such as cost, wireless capabilities, range of presets and battery life should also be considered.

Low-intensity low-frequency ultrasound mediates riboflavin delivery during corneal crosslinking

We employed the mechanical effect from 40 kHz ultrasound (US) to improve the delivery of riboflavin into corneal stroma for collagen crosslinking, which can benefit the treatment of keratoconus and other corneal ectasias. Experiments were conducted, first with porcine corneas ex vivo and then with New Zealand white rabbits in vivo, at varying mechanical index (MI) and sonication time. Results showed that 15 min of US applied on the cornea at MI = 0.8 in the presence of 0.5% of riboflavin solution enabled its delivery to deeper corneal stroma. Excessive heat was removed by a cooling setup to negate the thermal effect. The corneal absorption amount and penetration of riboflavin through cornea as detected by fluorotron, as well as the enhancement of corneal stiffness as measured by Young's modulus, were comparable to the conventional approach that requires complete corneal epithelium debridement. Histological analysis revealed minor exfoliation of superficial cell layers of corneal epithelium and loss of ZO-1 tight junctions immediately after US. Full recovery of the corneal epithelium and restoration of tight junctions occurred in 3-4 days. The study shows that low-intensity low-frequency ultrasound (LILF US) is a less invasive alternative to the conventional epithelium-off method for delivering riboflavin into the corneal stroma.

Ocular Ultrasound: Review of Bioeffects and Safety, Including Fetal and Point of Care Perspective: Review of Bioeffects and Safety, Including Fetal and Point-of-Care Perspective

Ocular ultrasound is an invaluable tool for the evaluation of the eye and orbit. However, the eye and orbit are potentially sensitive to the thermal and mechanical effects of ultrasound. When performing B-mode imaging, dedicated ocular settings should be used. If these settings are not available, limiting the acoustic output to Food and Drug Administration (FDA) recommended maximum levels is strongly advised. Especially important is the acoustic output in spectral (pulsed) and color Doppler modes, which can exceed the FDA's maximum recommended levels for the eye. Adjusting settings to decrease acoustic output and limiting the time of the examination should be done when performing a Doppler examination. The acoustic output of shear wave elastography is significantly higher than FDA guidelines for the eye and should be considered experimental.

Is Ocular Sonography a Reliable Method for the Assessment of Elevated Intracranial Pressure in Children?

Point-of-care ultrasound has been widely used by clinicians at the bedside in recent years. Various types of point-of-care ultrasound practices are employed, especially in pediatric emergency rooms and intensive care units. Pediatric intensive care specialists perform point-of-care ultrasound virtually as a part of physical examination since it provides just-in-time vital clinical information, which could assist in acute management strategies in critically ill patients. Measurement of optic nerve sheath diameter using point-of-care ultrasound is a noninvasive and radiation-free technique to determine raised intracranial pressure. Ophthalmic artery and central retinal artery Doppler indices can be used as transcranial Doppler to assess raised intracranial pressure. The aim of this review was to provide detailed information on ultrasonographic measurements of optic nerve sheath diameter and central retinal artery Doppler indices as techniques of interest for predicting increased intracranial pressure in pediatric patients in view of the literature.

Emergency Ocular Ultrasound - Common Traumatic and Non-Traumatic Emergencies Diagnosed with Bedside Ultrasound

Point-of-care ocular ultrasound (POCOUS) in the ambulatory and critical care setting has become an invaluable diagnostic tool for patients presenting with traumatic or atraumatic vision and ocular complaints. Sonographic bedside evaluation is intuitive and easy to perform and can accurately diagnose a variety of pathologies. These include detachment or hemorrhage of the retina or vitreous, lens dislocation, retrobulbar hematoma or air, as well as ocular foreign bodies, infections, tumors, and increased optic nerve sheath diameter that can be assessed in the setting of suspected increased intracranial pressure. The ocular anatomy is easy to visualize with sonography, as the eye is a superficial structure filled with fluid. Over the last two decades, a large number of scientific publications have documented that POCOUS in emergent or critical care settings is an accurate diagnostic tool and expands and improves emergency diagnosis and management. This article will review POCOUS exam techniques as well as normal sonographic findings and common pathologies.

EFSUMB Clinical Safety Statement for Diagnostic Ultrasound - (2019 revision)

This document is the updated 2019 revision of the EFSUMB Clinically Safety Statement. A Safety Statement has been published by EFSUMB annually since 1994 by the Safety Committee (ECMUS) of the federation. The text is deliberately brief and gives a concise overview of safety in the use of diagnostic ultrasound.

Optic Nerve Sheath Diameter and Retinal Artery Resistive Index Measurements with Bedside Ophthalmic Ultrasound in Pediatric Patients with Pseudotumor Cerebri Syndrome

Pseudotumor cerebri syndrome (PTCS) is characterized by raised intracranial pressure (ICP) with no neuroradiological abnormalities. Ocular ultrasound has been in use to measure optic nerve sheath diameter (ONSD), and retinal artery Doppler indices have been used for indirect assessment of ICP by pediatric intensivists. Here, we aimed to evaluate the correlation of the lumbar puncture (LP) opening pressure with the ultrasonographic ONSD and retinal resistive index (RRI) measures in patients with PTCS. And we wanted to find an answer to the following question: Can ultrasonographic ONSD measures serve as a follow-up tool in patients with PTCS? A prospective, single-center, case-control study was performed by pediatric intensive care and pediatric neurology departments. A total of 7 patients with PTCS were evaluated as patient group and 15 healthy children were evaluated as control group. The mean age of patient group was 138.8 ± 43.7 months. The mean right ONSD was 6.7 ± 0.5 mm and the mean left ONSD was 6.7 ± 0.6 mm. The mean right RRI value was 0.73 ± 0.03 and the mean left RRI was 0.73 ± 0.09. For the patient group, ONSD and RRI values of both eyes were statistically significant higher values than for the control group. The mean LP opening pressure was 56.57 ± 16.36 cmH ₂ O. We detected strong, positive, and statistically significant correlations between the LP opening pressure and ONSD baseline measures for both the right eye ( r  = 0.882, p  = 0.009) and the left eye ( r  = 0.649, p  = 0.004). There was no correlation between opening pressure in LP and RRI measurements. We detected a statistically significant decrease in the right ONSD and left ONSD values and visual analog scale scores at the third-month follow-up. Our study results demonstrate that ultrasonographic ONSD measurements can be used as a noninvasive tool for assessment of the ICP at first admission and can be used as a follow-up tool in PTSC patients.

Determination of normal values of optic nerve sheath diameter in newborns with bedside ultrasonography

OBJECTIVES

Bedside sonographic opthalmic ultrasound measurement of optic nerve sheath diameter (ONSD) is an easy, portabl, noninvasive and a radiation free technique to determine increased intracranial pressure. This prospective, multicenter study was aimed to establish the range of normal values for ONSD in preterm and term newborns with a large study population.

METHODS

Newborns without intracranial pathology in the Newborn Intensive Care Units and in Obstetrics and Gynecology Departments were enrolled in the study. ONSD was measured at 3 mm distance behind of the right optic nerve head. As 3 mm distance was beyond the optic nerve head in some of the premature newborns, we had also measurements at 2 and 2.5 mm.

RESULTS

ONSD was measured in 554 newborns. Mean ONSD of preterm babies at 2, 2.5 and 3 mm distances were 3.2 ± 0.3 mm (range 2.0-4.2 mm), 3.3 ± 0.3 mm (range 2.2-4.5 mm) and 3.6 ± 0.2 mm (range 2.9-4.5 mm), (p_{2.0-2.5 mm} < 0.001, p _2.5-3.0mm < 0.001, p_{2.0-3.0 mm} < 0.001) respectively. Mean ONSD of term babies at 3 mm was higher than the mean ONSD of preterm babies in 33 weeks 0 day- 37 weeks 0 days group (p < 0.001). In correlation analysis, a significant, strong and positive correlation was found between ONSD measurements and gestational age, weight, height and head circumference at 2, 2.5 and 3 mm distances.

CONCLUSION

The normal values reported by the present study may be used for evaluating the ONSD of newborns with different conditions with increased incracranial pressure.