The diagnostic accuracy and prognostic value of OCT for the evaluation of the visual function in children with a brain tumour: A systematic review

Purpose

To systematically review the evidence on the diagnostic accuracy and prognostic value of retinal optical coherence tomography (OCT) to detect visual acuity (VA) or visual field (VF) loss in children with a brain tumour.

Methods

PubMed, Embase and Cochrane Library databases were searched from inception to February 2021. We included studies evaluating retinal OCT and standard visual function parameters (VA and or VF) in children with a brain tumour. Two authors independently extracted data from each included study. They also assessed the methodological quality of the studies using the QUADAS-2 or QUIPS tool. The diagnostic accuracy of OCT was evaluated with receiver operating characteristic analysis, sensitivity, specificity, positive predictive value and negative predictive value. The prognostic value of OCT was evaluated with predictive measures (odds ratio).

Results

We included five diagnostic studies, with a total of 186 patients, all diagnosed with optic pathway glioma. No prognostic studies were eligible for inclusion. Included studies evaluated either retinal nerve fiber layer (RNFL) thickness or ganglion cell layer—inner plexiform layer (GCL-IPL) thickness. There was considerable heterogeneity between OCT devices, OCT protocols, visual function parameters and threshold values. Sensitivity and specificity for RNFL thickness measurement ranged from 60.0% to 100.0% and 76.6% to 100%, respectively. For GCL-IPL thickness measurement, area under the curve ranged from 0.91 to 0.98 for different diameters.

Conclusion

The literature regarding the diagnostic accuracy and prognostic value of OCT parameters in children with a brain tumour is scarce. Due to heterogeneity and a considerable risk of bias of included studies, we cannot draw solid conclusions regarding the accuracy of retinal OCT. Future research should investigate the potential of OCT as diagnostic and prognostic tool for the evaluation of the visual function and detection of visual impairment in children with any type of brain tumour.

Vision Outcomes for Pediatric Patients With Optic Pathway Gliomas Associated With Neurofibromatosis Type I: A Systematic Review of the Clinical Evidence

Children with neurofibromatosis type I (NF1) have a higher predisposition for low-grade astrocytomas of the optic pathway, commonly referred to as optic pathway gliomas (OPGs). OPGs can result in visual deterioration. Treatment outcomes in OPG-NF1 management are often reported around tumor stabilization. We sought to compare vision outcomes associated with different OPG treatment strategies to inform about this important functional metric. A meta-analysis exploring the different modalities to treat children with OPG-NF1 was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using multiple databases. Of the 113 articles identified in the search, 23 full text articles, representing 564 patients, were included for review. These articles included retrospective, prospective, and randomized controlled studies on observation (n=9), chemotherapy (n=19), radiation therapy (n=6), and surgery (n=7). Of the patients undergoing observation, 87% (60/69) demonstrated stable acuity. In the chemotherapy studies, 27.3% (72/264) demonstrated improved acuity/visual field and/or visual-evoked potential amplitudes, 39.4% (104/264) stable acuity, and 33.3% (88/264) deterioration. Both the radiation and surgical treatments reported worsening acuity at 90.9% (10/11) and 73.3% (11/15), respectively. Causal associations are not known. Indications for and timing of treatment choice warrant larger scale study to provide further understanding.

Visual outcomes following everolimus targeted therapy for neurofibromatosis type 1-associated optic pathway gliomas in children

Data for visual acuity (VA) after treatment of neurofibromatosis type 1-associated optic pathway gliomas (NF1-OPGs) are limited. We retrospectively collected VA, converted to logMAR, before and after targeted therapy with everolimus for NF1-OPG, and compared to radiologic outcomes (14/18 with NF1-OPG, 25 eyes [three without quantifiable vision]). Upon completion of treatment, VA was stable in 19 eyes, improved in four eyes, and worsened in two eyes; visual and radiologic outcomes were discordant. In summary, the majority of children with NF1-OPG exhibited stabilization of their VA after everolimus treatment. A larger, prospective study will help delineate visual outcomes after targeted therapy.

Assessment of the visual pathways in patients with neurofibromatosis-1 by 3S-space technique with 3-Tesla MRI

Background/aim

We aimed to evaluate the size/tortuosity of the optic nerve (ON) and the dilatation of the ON sheath (ONS) in neurofibromatosis type 1 (NF-1) patients with 3T-MRI, and to assess the usefulness of 3D-SPACE in imaging the optic pathway, ON, and ONS in NF-1 patients.

Materials and methods

Twenty consecutive NF-1 patients without optic pathway glioma (OPG) (Group 1), 16 consecutive NF-1 patients with OPG (Group 2), and 19 controls were included in this study. The thickness and tortuosity of the ON and the diameter of the ONS were measured on STIR and 3D-SPACE images.

Results

The thickness of the ON was similar in all groups on STIR images (P>0.05). The mean ONS diameter was higher in Group 2 with this sequence (P=0.009). Controls had significantly lower grades of ON tortuosity than Groups 1 and 2 (P=0.001), and Group 1 had significantly lower ON tortuosity compared to Group 2 (P=0.001). Severe tortuosity was only detected in Group 2.

Conclusion

ON tortuosity and ONS diameter were increased in NF-1 patients in the presence of OPG. High-resolution cranium imaging with the 3D-SPACE technique using 3T-MRI seems to be helpful for detection of the optic pathway morphology and pathologies in NF-1 patients.

Electrophysiological monitoring in a patient with an optic nerve glioma

PURPOSE

To report a case illustrating the value of pattern VEP and pattern ERG (PERG) in monitoring optic nerve gliomata (OG).

CASE REPORT

A 15-year-old girl presented with a 3-year history of frontal headaches and a 5-month history of blurred vision in the right eye. MRI scanning revealed a thickened, right optic nerve extending to the cranial opening of the optic canal, consistent with an optic nerve glioma. Pattern VEP showed a mildly delayed major positive component consistent with optic nerve dysfunction. The PERG N95:P50 ratio was subnormal in keeping with retinal ganglion cell involvement. Visual acuity decreased over the following 2 years and repeat VEP objectively demonstrated marked deterioration in optic nerve function despite neuroradiology showing no significant change in the tumour.

CONCLUSIONS

Pattern VEPs and pattern ERGs can provide early objective evidence of optic nerve/retinal ganglion cell dysfunction in optic nerve gliomata. Serial recordings can objectively demonstrate worsening function in the absence of significant neuroradiological change.

Neurosurgical implications of neurofibromatosis Type I in children

Neurofibromatosis Type 1 (NF1) is one of the most common inherited diseases in humans. It is caused by a mutation in the NF1 gene on chromosome 17, and is associated with numerous central and peripheral nervous system manifestations. Children with NF1 are at high risk of harboring numerous lesions that may require the attention of a neurosurgeon. Some of these include optic nerve gliomas, hydrocephalus, intraspinal tumors, and peripheral nerve tumors. Although most of the neoplasms that affect the brain, spine, and peripheral nerves of children are low-grade lesions, there is a small but real risk that some of these lesions may become high grade over time, requiring other forms of therapy than surgery alone. Other associated disorders that may result from NF1 in childhood include Chiari malformation Type I, scoliosis, and pulsating exophthalmos from the absence of the sphenoid wing. In this review, the major lesions that are found in children with NF1 are reviewed as well as the types of treatment that are offered by neurosurgeons and other members of the treating team. Today, optimum care of the child with NF1 is provided by a multidisciplinary team comprising neurosurgeons, neurologists, ophthalmologists, radiologists, orthopedic surgeons, and plastic surgeons.

Optic Nerve Glioma and Optic Neuritis Mimicking One Another: Case Report

OBJECTIVE AND IMPORTANCE:

The clinical and radiographic presentations of optic nerve gliomas and optic neuritis are for the most part distinct and their diagnoses straightforward. We present two cases illustrating the occasional difficulty one can encounter in distinguishing neoplastic from inflammatory optic neuropathies.

CLINICAL PRESENTATION:

Patient 1 is a 17-year-old girl who presented with acute onset of pain and rapidly progressive visual loss in the right eye. Patient 2 is a 38-year-old man who presented with painless progressive visual loss in the left eye.

INTERVENTION:

Patient 1 was initially diagnosed with idiopathic retrobulbar optic neuritis. Interval increase of the optic nerve on magnetic resonance imaging prompted a biopsy of the optic nerve, which revealed a pilocytic astrocytoma. Patient 2 was found to have left optic nerve enhancement most consistent with an optic nerve glioma. Before a biopsy, the patient spontaneously improved without treatment, indicating an inflammatory process.

CONCLUSION:

Differentiating between optic nerve neoplasm and inflammation may be difficult. On occasion, the classic clinical finding of pain with eye movement and the radiographic finding of enlargement and enhancement of the optic nerve may be misleading. Open biopsy of the optic nerve is indicated only after a completely negative metabolic, infectious, and inflammatory workup; interval increase of the optic nerve on magnetic resonance imaging; and failure of the patient to recover vision.

A fast visual evoked potential method for functional assessment and follow-up of childhood optic gliomas

OBJECTIVE

To evaluate a fast technique of visual evoked potentials (VEPs) recording, in response to steady-state luminance stimuli (SS-LVEPs), for functional assessment and follow-up of childhood optic gliomas (OGs).

METHODS

Eighteen OG patients (age range: 3.5-18 years), with different degrees of optic pathway damage severity, were examined. Sixteen age-matched normal subjects served as controls. Ten of the 18 OG patients were re-tested 1-3 months after the first examination. SS-LVEPs were elicited by a sinusoidally-modulated flickering (8 Hz) uniform field, generated by a light emitting diode (LED)-array and presented monocularly in a mini-ganzfeld. Amplitude and phase of the Fourier-analyzed response fundamental (1F) and second harmonic (2F) were measured. The full VEP protocol had a median duration of 6 min (range: 4-12).

RESULTS

When compared to normal control values, median 1F and 2F SS-LVEP amplitudes of OG patients were reduced (P<0.01), with a borderline increase in 2F phase lag (P<0.05). In 11 OG patients with asymmetric optic pathway damage in between-eye comparisons, median 1F amplitude losses were greater (P<0.01) in fellow eyes with more severe damage. No significant interocular difference was observed in control subjects. Median test-retest changes of 1F and 2F component were <20% and 30 degrees for amplitude and phase, respectively. In individual OG patients, 1F and 2F amplitudes were positively correlated (P<0.01) with visual acuity. 1F amplitude losses were correlated (P=0.01) with the severity of optic disc atrophy. Considering both 1F and 2F abnormalities, diagnostic sensitivity of SS-LVEP in detecting OG-induced optic pathways damage was 83.3%.

CONCLUSIONS

The present findings support the use of this technique, as an alternative to pattern VEPs, for functional assessment and follow-up of OG in uncooperative children.

Rest-activity patterns in children with hypopituitarism

OBJECTIVES

Physical lesions in the region of the suprachiasmatic nuclei, which are the site of a circadian clock, result in abnormal circadian rhythmicity in animals, yet the extent of biological rhythm problems in individuals with anatomic or functional lesions in the hypothalamic-pituitary region are largely unknown. To address this issue, we examined patterns of rest and activity of children with hypopituitarism.

METHODS

Children who were between the ages of 2 and 18 years and had the diagnosis of panhypopituitarism were evaluated. Twenty children were studied, including children with septo-optic dysplasia (SOD), congenital hypopituitarism, brain tumors, closed head trauma, and head irradiation. For assessing patterns of activity, individuals wore Actiwatches for 3-4 weeks to measure patterns of gross motor activity.

RESULTS

Seventeen children had normal patterns of rest and activity, with an average period length of 24.01 +/- 0.01 hours. Three children, including 2 with SOD and 1 with a hypothalamic germinoma, showed abnormal activity patterns in which there was not consolidated rest at night. One patient with an optic glioma had nonentrained circadian phase.

CONCLUSIONS

A proportion of children with hypopituitarism have abnormal daily rest-activity patterns. Children with anterior hypothalamic tumors and SOD seem to be at risk for circadian system dysfunction.

Long-term outcome in children with gliomas of the anterior visual pathway

We performed a retrospective assessment of the long-term visual, neurologic, and systemic outcomes of 47 patients with anterior visual pathway gliomas seen at the Johns Hopkins Hospital. All of the patients had follow-up of at least 10 years or died during the follow-up period. Two patients died before 10 years of follow-up were achieved. The remaining 45 patients (including three patients who subsequently died) had follow-up of 10-28 years (mean, 15.3 years; median, 15 years). Sixteen of the patients in this study, most of whom had neurofibromatosis type 1 (NF1), received no treatment. None of these patients died or developed neurologic morbidity as a result of their tumor. Thirty-one of the patients, most of whom did not have evidence of NF1, received treatment. Many of these patients subsequently developed neurologic, endocrine, or visual morbidity. However, although patients with anterior visual pathway gliomas who were not treated fared better visually, neurologically, and systemically than patients who were treated, patients who required treatment for progression generally had a good overall prognosis, particularly patients with tumors that did not involve the hypothalamus. Most of these patients survived and maintained useful vision in at least one eye. We believe that patients with anterior visual pathway gliomas, particularly those with NF1, should not be treated unless there is clear clinical or neuroimaging evidence of progression.

Diffusion MRI in neurofibromatosis type 1: ADC evaluations of the optic pathways, and a comparison with normal individuals

In a control group of 12 normal children (ages ranging from 9 months to 3 years; mean=1.6 years) the mean apparent diffusion coefficient (ADC) value of the normal white matter, obtained from automatically generated ADC maps, was 0.84 +/- 0.14 x 10(-3)mm(2)/s. A patient with neurofibromatosis type 1 with bilateral optic gliomas, and extensive optic pathway involvement was evaluated by diffusion MRI. Multiple measurements of ADC values throughout the involved optic radiations revealed a higher mean value: 1.16 +/- 0.06 x 10(-3)mm(2)/s than that of the normal white matter, suggesting relatively high molecular motion in these regions, probably representing myelin vacuolization. ADC evaluation of a thalamic hamartoma revealed a lower value (=1.06 x 10(-3)mm(2)/s) than this. The mean ADC value obtained from multiple measurements of the enlarged optic chiasm, and intraorbital portions of the nerve was similar (=0.81+/- 0.09 x 10(-3)mm(2)/s) to that of the normal cerebral white matter of the control cases. It appears that diffusion imaging can be useful in evaluation of optic pathway involvement in NF1, and might contribute to differentiating optic gliomas from hamartomas, and myelin vacuolization, however, further studies will be required for assessing the role of diffusion imaging in such lesions.

Spontaneous regression of optic gliomas: thirteen cases documented by serial neuroimaging

OBJECTIVE

To demonstrate spontaneous regression of large, clinically symptomatic optic pathway gliomas in patients with and without neurofibromatosis type 1 (NF-1).

METHODS

Patient cases were collected through surveys at 2 consecutive annual meetings of the North American Neuro-Ophthalmology Society (NANOS) and through requests on the NANOSNET Internet listserv. Serial documentation of tumor signal and size, using magnetic resonance imaging in 11 patients and computed tomography in 2 patients, was used to evaluate clinically symptomatic optic pathway gliomas. All tumors met radiologic criteria for the diagnosis of glioma and 4 patients had biopsy confirmation of their tumors. In 3 patients, some attempt at therapy had been made many years before regression occurred. In one of these, radiation treatment had been given 19 years before tumor regression, while in another, chemotherapy had been administered 5 years before signal changes in the tumor. In the third patient, minimal surgical debulking was performed 1 year before the tumor began to shrink.

RESULTS

Spontaneous tumor shrinkage was noted in 12 patients. Eight patients did not have NF-1. In an additional patient without NF-1, a signal change within the tumor without associated shrinkage was detected. Tumor regression was associated with improvement in visual function in 10 of 13 patients, stability of function in 1, and deterioration in 2.

CONCLUSIONS

Large, clinically symptomatic optic gliomas may undergo spontaneous regression. Regression was seen in patients with and without NF-1. Regression may manifest either as an overall shrinkage in tumor size, or as a signal change on magnetic resonance imaging. A variable degree of improvement in visual function may accompany regression. The possibility of spontaneous regression of an optic glioma should be considered in the planning of treatment of patients with these tumors.

Long-term visual outcome in patients with anterior visual pathway gliomas

OBJECTIVES

To investigate the visual outcomes of patients with gliomas of the anterior visual pathway and the clinical features associated with prognosis.

MATERIALS AND METHODS

During retrospective review, demographic and clinical data were abstracted from medical records of patients seen at the Bascom Palmer Eye Institute between January 1, 1970 and December 31, 1998.

RESULTS

Of the 42 patients identified, 68% were female, and 55% had neurofibromatosis (NF) type I. There was no substantial difference in presenting signs, symptoms, and visual acuity between the NF(+) and NF(-) groups except for nystagmus, which was more common in the NF(-) group (p = 0.014). Throughout follow-up evaluation, vision in the better eye remained stable in both groups, independent of treatment or NF status. Vision in the worse eye often declined, despite treatment. However, binocular visual status, measured as average weighted logMAR (MAR, minimum angle of resolution) vision, did not change significantly over time, regardless of treatment or NF status.

CONCLUSIONS

In the NF(+) and NF(-) groups, vision in the better eye remained stable, regardless of treatment, and vision in the worse eye often declined, despite treatment. Binocular visual acuity (measured as weighted logMAR) did not change significantly over time, regardless of NF status or treatment modality.

Visual-evoked potentials in the assessment of optic gliomas

The most effective method for the screening and monitoring of optic pathway gliomas in children with neurofibromatosis type 1 remains a dilemma. Children less than 6 years of age are the group at highest risk for the development of optic pathway gliomas. Although an annual ophthalmologic examination currently is recommended as the most efficient method to screen for optic pathway gliomas, this method is often unreliable and inaccurate in young children. Magnetic resonance imaging remains the most sensitive test; however, cost and the need for sedation or general anaesthetic preclude its use as a routine screening test. We previously have recommended visual-evoked potentials (VEPs) as a possible alternative or aid in the assessment of optic pathway gliomas in this group of patients. The aims of this study were to ascertain the sensitivity of VEPs in detecting optic pathway gliomas and to determine whether VEPs are useful in monitoring the progress of optic pathway gliomas. This study provides further evidence of the sensitivity of VEPs in detecting optic pathway gliomas. In addition, VEPs may provide additional useful information concerning the progression of optic pathway gliomas once they have been detected.

Neurofibromatosis type 1 and McCune-Albright syndrome occurring in the same patient

A patient with both neurofibromatosis type 1 (NF-1) and McCune-Albright syndrome is described. NF-1 and McCune-Albright are separate entities and this is the first report of a patient with clear evidence of both conditions.