Length of optic nerve double inversion recovery hypersignal is associated with retinal axonal loss

Value of Optic Nerve MRI in Multiple Sclerosis Clinical Management: A MAGNIMS Position Paper and Future Perspectives

The optic nerve is frequently involved in multiple sclerosis (MS). However, MRI of the optic nerve is considered optional in the differential diagnosis of optic neuropathy symptoms either at presentation or in established MS. In addition, unlike spinal cord imaging in comparable scenarios, no role is currently recommended for optic nerve MRI in patients presenting with optic neuritis for its confirmation, to plan therapeutic strategy, within the MS diagnostic framework, nor for the detection of subclinical activity in established MS. In this article, evidence related to these 3 aspects will be summarized and gaps in knowledge will be highlighted, including (1) the acquisition challenges and novel sequences that assess pathologic changes within the anterior visual pathways; (2) the clinical implications of quantitative magnetic resonance studies of the optic nerve, focusing on atrophy measures, magnetization transfer, and diffusion tensor imaging; and (3) the relevant clinical studies performed to date. Finally, an algorithm for the application of optic nerve MRI will be proposed to guide future studies aimed at addressing our knowledge gaps.

How far should I manage acute optic neuritis as an ophthalmologist? A United Kingdom perspective

Optic neuritis (ON) is an inflammation of or around the optic nerve, frequently caused by infectious or immune-mediated inflammatory disorders. In the UK, its strongest association is with Multiple Sclerosis (MS), though the combined prevalence of other associated infectious and immune-mediated inflammatory diseases (I-IMID) is similar to that of MS-ON. Prompt identification and understanding of ON's underlying cause informs tailored management and prognosis. Several IMIDs linked to ON, such as aquaporin-4 antibody-associated optic neuritis (AQP4-ON), myelin oligodendrocyte glycoprotein antibody-associated optic neuritis (MOG-ON), and neuro-sarcoidosis, show remarkable response to corticosteroid treatment. Therefore, urgent investigation and treatment are crucial in cases 'atypical' for MS-ON. Following the 1992 Optic Neuritis Treatment Trial, clinical practice has evolved, with short-course high-dose corticosteroids considered safe and effective for most people. Timely recognition of patients who could benefit is critical to avoid irreversible vision loss. This review provides a practical guide and a summary of evidence on the investigation and management of acute optic neuritis. It reflects the knowledge and limitations of current evidence, framed through the neuro-ophthalmic perspective of clinical practice at multiple UK academic centres.

Optic Nerve Imaging in Multiple Sclerosis and Related Disorders

Optic neuritis is a common feature in multiple sclerosis and in 2 other autoimmune demyelinating disorders such as aquaporin-4 IgG antibody-associated neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein antibody-associated disease. Although serologic testing is critical for differentiating these different autoimmune-mediated disorders, MR imaging, which is the preferred imaging modality for assessing the optic nerve, can provide valuable information, suggesting a specific diagnosis and guiding the appropriate serologic testing.

Retinal optical coherence tomography measures in multiple sclerosis: a systematic review and meta-analysis

Spectral domain-optical coherence tomography plays a crucial role in the early detection and monitoring of multiple sclerosis (MS) pathophysiology. We aimed to quantify differences in retinal layer measures among different groups of MS and explored different variables that correlate with retinal measures. This study was reported according PRISMA guidelines. A comprehensive search was done across PubMed, Embase, and Google Scholar. The mean difference in thickness of retinal layers and macular volume was assessed. Meta-regression was done to assess the sources of heterogeneity. A total of 100 articles were included in the meta-analyses. The peripapillary retinal nerve fiber layer (pRNFL) thickness significantly decreased in the MSON (MD: -16.44, P < 0.001), MSNON (MD: -6.97, P < 0.001), and PMS (MD: -11.35, P < 0.001) versus HC. The macular RNFL was lower among the MSON (MD: -6.24, P = 0.013) and MSNON (MD: -3.84, P <0.001) versus HC. Macular ganglion cell layer and inner plexiform layer (GCIPL) was thinner among MSON (MD: -14.83, P <0.001), MSNON (MD: -6.38, P < 0.001), and PMS (MD: -11.52, P < 0.001) compared with control eyes. Inner nuclear layer (INL) was higher in the MSON (MD: 0.49, P < 0.001) versus HC. Outer nuclear layer (ONL) thickness significantly lower in the MSNON (MD: -1.15, P = 0.019) versus HC. Meta-regression showed that disease duration, age, EDSS score, and percentage of patients taking DMT are all negatively correlated with pRNFL and GCIPL thickness; however, female gender was correlated with less atrophy. As conclusion, the study highlights substantial thinning in the pRNFL and macular GCIPL between MS versus controls. INL as valuable parameter for capturing inflammatory disease activity.

Association of plasma sPD-1 and sPD-L1 with disease status and future relapse in AQP4-IgG (+) NMOSD

OBJECTIVE

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune-mediated disorder with aquaporin 4-immunoglobulin G (AQP4-IgG) in most settings. Soluble programmed death-1 (sPD-1) and soluble programmed death ligand 1 (sPD-L1) play key roles in immunomodulation. We aim to assess the association of sPD-1 and sPD-L1 with cytokines and their clinical significance in AQP4-IgG (+) NMOSD.

METHOD

We measured plasma sPD-1, sPD-L1, and 10 cytokines levels of 66 AQP4-IgG (+) NMOSD patients, including 40 patients in attack (attack-NMOSD) and 26 patients in remission (remission-NMOSD) phases, and 28 healthy controls through ultrasensitive Simoa and SP-X platform, respectively. We also performed >2 years (median) of follow-up after testing and analyzed the relationship between the detection index and current and future clinical parameters.

RESULT

Plasma sPD-1 level discriminated attack-NMOSD from remission-NMOSD (AUC = 0.692, p = 0.009). sPD-1 and sPD-L1 levels positively correlated with IL-6 (rsPD-1  = 0.313; rsPD-L1  = 0.508), IFN-γ (rsPD-1  = 0.331; rsPD-L1  = 0.456), and TNF-α (rsPD-1  = 0.451; rsPD-L1  = 0.531) expression, as well as clinical indicators, including the EDSS score (rsPD-1  = 0.331; rsPD-L1  = 0.402), number of attacks (rsPD-1  = 0.431) and segments of spinal cord involvement (rsPD-1  = 0.462; rsPD-L1  = 0.508). The risk of relapse within 2 years after sampling was associated with higher sPD-1/sPD-L1 ratio in attack-NMOSD (p = 0.022; Exp(B) = 1.589).

INTERPRETATION

Plasma sPD-1 and sPD-L1 levels reflected current disease severity and activity, and predicted future relapses in AQP4-IgG (+) NMOSD, suggesting that they hold the potential to guide timely and targeted treatment.

Diagnosis and classification of optic neuritis

There is no consensus regarding the classification of optic neuritis, and precise diagnostic criteria are not available. This reality means that the diagnosis of disorders that have optic neuritis as the first manifestation can be challenging. Accurate diagnosis of optic neuritis at presentation can facilitate the timely treatment of individuals with multiple sclerosis, neuromyelitis optica spectrum disorder, or myelin oligodendrocyte glycoprotein antibody-associated disease. Epidemiological data show that, cumulatively, optic neuritis is most frequently caused by many conditions other than multiple sclerosis. Worldwide, the cause and management of optic neuritis varies with geographical location, treatment availability, and ethnic background. We have developed diagnostic criteria for optic neuritis and a classification of optic neuritis subgroups. Our diagnostic criteria are based on clinical features that permit a diagnosis of possible optic neuritis; further paraclinical tests, utilising brain, orbital, and retinal imaging, together with antibody and other protein biomarker data, can lead to a diagnosis of definite optic neuritis. Paraclinical tests can also be applied retrospectively on stored samples and historical brain or retinal scans, which will be useful for future validation studies. Our criteria have the potential to reduce the risk of misdiagnosis, provide information on optic neuritis disease course that can guide future treatment trial design, and enable physicians to judge the likelihood of a need for long-term pharmacological management, which might differ according to optic neuritis subgroups.

Improved detection of multiple sclerosis lesions with T2-prepared double inversion recovery at 3T

BACKGROUND AND PURPOSE

Double inversion recovery (DIR) imaging is used in multiple sclerosis (MS) clinical protocols to improve the detection of cortical and juxtacortical gray matter lesions by nulling confounding signals originating from the cerebrospinal fluid and white matter. Achieving a high isotropic spatial resolution, to depict the neocortex and its typically small lesions, is challenged by the reduced signal-to-noise ratio (SNR) determined by multiple tissue signal nulling. Here, we evaluate both conventional and optimized DIR implementations to improve tissue contrast (TC), SNR, and MS lesion conspicuity.

METHODS

DIR images were obtained from MS patients and healthy controls using both conventional and prototype implementations featuring a T2-preparation module (T2P), to improve SNR and TC, as well as an image reconstruction routine with iterative denoising (ID). We obtained quantitative measures of SNR and TC, and evaluated the visibility of MS cortical, cervical cord, and optic nerve lesions in the different DIR images.

RESULTS

DIR implementations adopting T2P and ID enabled improving the SNR and TC of conventional DIR. In MS patients, 34% of cortical, optic nerve, and cervical cord lesions were visible only in DIR images acquired with T2P, and not in conventional DIR images. In the studied cases, image reconstruction with ID did not improve lesion conspicuity.

CONCLUSIONS

DIR with T2P should be preferred to conventional DIR imaging in protocols studying MS patients, as it improves SNR and TC and determines an improvement in cortical, optic nerve, and cervical cord lesion conspicuity.

Optic Nerve Lesion Length at the Acute Phase of Optic Neuritis Is Predictive of Retinal Neuronal Loss

Background and Objectives

Acute optic neuritis (ON) is a classical presenting symptom of multiple sclerosis (MS), neuromyelitis optica spectrum disorders (NMOSD), and anti–MOG-associated disorders. The resulting visual impairment is variable and can be severe. Clinicians are in need of predictive biomarkers to optimize the management of acute ON. In this longitudinal study (IRMANO, NCT03651662), we evaluated the ability of optic nerve lesion length measured on MRI at the acute phase of ON to predict retinal neuro-axonal loss and visual impairment at a chronic stage.

Methods

We conducted a longitudinal study (IRMANO, NCT03651662) of patients who presented a clinical episode of ON (≤8 weeks). All patients underwent a retinal optical coherence tomography (OCT) and a brain/optic nerve MRI, including 3D double-inversion recovery (DIR) sequence at the acute phase of ON and 12 months later. Primary outcomes were optic nerve DIR hypersignal lesion length, macular ganglion cell–inner plexiform layer (GCIPL) volume measured on OCT, and low-contrast monocular visual acuity (LCMVA).

Results

The study group included 51 patients (33 women, mean age of 32.4 years ± 7.9). We recruited patients with a clinically isolated syndrome (n = 20), a relapsing-remitting MS (n = 23), an isolated ON (n = 6), and a first clinical episode of NMOSD (n = 2). Optic nerve DIR hypersignal was observed in all but 1 symptomatic optic nerves. At inclusion, the mean optic nerve lesion length (in mm) was 12.35 ± 5.98. The mean GCIPL volume (in mm³) significantly decreased between inclusion (1.90 ± 0.18) and M₁₂ (1.67 ± 0.21; p < 0.0001). Optic nerve lesion length at inclusion was significantly associated with GCIPL thinning (estimate ± SD; −0.012 ± 0.004; p = 0.0016) and LCMVA at M₁₂ (0.016 ± 0.003; p < 0.001). Optic nerve lesion length significantly increased at M₁₂ (15.76 ± 8.70; p = 0.0007). The increase in optic nerve lesion length was significantly associated with the GCIPL thinning between inclusion and M₁₂ (−0.012 ± 0.003; p = 0.0011).

Discussion

At the acute phase of ON, optic nerve lesion length is an imaging biomarker predictive of retinal neuro-axonal loss and chronic visual impairment, which can help to stratify future therapeutic strategies in acute ON.

Classification of Evidence

This study provides Class I evidence that optic nerve lesion length measured on MRI during the acute phase of a first episode of ON is associated with long-term retinal neuro-axonal loss and visual impairment.

Dedicated 3D-T2-STIR-ZOOMit Imaging Improves Demyelinating Lesion Detection in the Anterior Visual Pathways of Patients with Multiple Sclerosis

BACKGROUND AND PURPOSE

Demyelinating lesions in the anterior visual pathways represent an underestimated marker of disease dissemination in patients with MS. We prospectively investigated whether a dedicated high-resolution MR imaging technique, the 3D-T2-STIR-ZOOMit, improves demyelinating lesion detection compared with the current clinical standard sequence, the 2D-T2-STIR.

MATERIALS AND METHODS

3T MR imaging of the anterior visual pathways (optic nerves, chiasm, and tracts) was performed using 3D-T2-STIR-ZOOMit and 2D-T2-STIR, in patients with MS and healthy controls. Two experienced neuroradiologists assessed, independently, demyelinating lesions using both sequences separately. 3D-T2-STIR-ZOOMit scan-rescan reproducibility was tested in 12 patients. The Cohen κ was used for interrater agreement, and the intraclass correlation coefficient for reproducibility. Between-sequence detection differences and the effects of location and previous acute optic neuritis were assessed using a binomial mixed-effects model.

RESULTS

Forty-eight patients with MS with (n = 19) or without (n = 29) past optic neuritis and 19 healthy controls were evaluated. Readers' agreement was strong (3D-T2-STIR-ZOOMit: 0.85; 2D-T2-STIR: 0.90). The 3D-T2-STIR-ZOOMit scan-rescan intraclass correlation coefficient was 0.97 (95% CI, 0.96-0.98; P < .001), indicating excellent reproducibility. Overall, 3D-T2-STIR-ZOOMit detected more than twice the demyelinating lesions (n = 89) than 2D-T2-STIR (n = 43) (OR = 2.7; 95% CI, 1.7-4.1; P < .001). In the intracranial anterior visual pathway segments, 33 of the 36 demyelinating lesions (91.7%) detected by 3D-T2-STIR-ZOOMit were not disclosed by 2D-T2-STIR. 3D-T2-STIR-ZOOMit increased detection of demyelinating lesion probability by 1.8-fold in patients with past optic neuritis (OR = 1.8; 95% CI, 1.2-3.1; P = .01) and 5.9-fold in patients without past optic neuritis (OR = 5.9; 95% CI, 2.5-13.8; P < .001). No false-positive demyelinating lesions were detected in healthy controls.

CONCLUSIONS

Dedicated 3D-T2-STIR-ZOOMit images improved substantially the detection of MS disease dissemination in the anterior visual pathways, particularly in the intracranial segments and in patients without past optic neuritis.

Recent advances on optic nerve magnetic resonance imaging and post-processing

The optic nerve is known to be one of the largest nerve bundles in the human central nervous system. There have been many studies of optic nerve imaging and post-processing that have provided insights into pathophysiology of optic neuritis related to multiple sclerosis and neuromyelitis optica spectrum disorder, glaucoma, and Leber's hereditary optic neuropathy. There are many challenges in optic nerve imaging, due to the morphology of the nerve through its course to the optic chiasm, its mobility due to eye movements and the high signal from cerebrospinal fluid and orbital fat surrounding the optic nerve. Recently, many advanced and fast imaging sequences have been used with post-processing techniques in attempts to produce higher resolution images of the optic nerve for evaluating various diseases. Magnetic resonance imaging (MRI) is one of the most common imaging methodologies for the optic nerve. This review paper will focus on recent MRI advances in optic nerve imaging and explain several post-processing techniques being used for analysis of optic nerve images. Finally, some challenges and potential for future optic nerve studies will be discussed.

Teriflunomide treatment is associated with optic nerve recovery in early multiple sclerosis

Background and aims:

Various attempts have been made to support recovery following optic neuritis (ON), but the respective trials have mostly been negative. The aim of this study was to determine whether disease-modifying treatment (DMT) following ON as first manifestation of relapsing-remitting multiple sclerosis influences long-term outcomes.

Methods:

A total of 79 patients with ON were identified and evaluated at relapse, DMT induction, and 12 months following treatment induction with either glatiramer acetate (GLAT), interferon-beta (IFN), or teriflunomide (TRF). Low-contrast letter acuity (LCLA) and full-field visual-evoked potentials (FF-VEP) were compared between treatment groups using multivariable regression models. The impact of TRF treatment induction compared with IFN or GLAT following relapses outside the optic nerves was evaluated in an independent cohort of 122 patients. Magnetic resonance imaging (MRI) outcomes and rates of confirmed improvement of relapse-related disability were evaluated.

Results:

TRF-treated patients exhibited higher LCLA and lower relative P100 latencies normalized to the fellow-eye. Findings were significant following covariate-adjustment by multivariable analyses. Cranial MRI lesion load as well as disability progression rates were not significantly different between groups. The cohort of patients following relapses other than ON showed no differences in confirmed improvement of disability.

Conclusion:

TRF treatment is associated with favorable outcomes regarding functional optic nerve recovery following ON in early multiple sclerosis.

Gadolinium-Enhanced 3D T1-Weighted Black-Blood MR Imaging for the Detection of Acute Optic Neuritis

BACKGROUND AND PURPOSE

A 3D T1-weighted black-blood sequence was recently shown to improve the detection of contrast-enhancing lesions in the brain in patients with MS compared with a 3D T1-weighted MPRAGE sequence. We compared a contrast-enhanced 3D T1-weighted black-blood sequence with a dedicated orbital contrast-enhanced T1-weighted Dixon sequence in patients with acute optic neuritis.

MATERIALS AND METHODS

MR imaging data (3T) of 51 patients showing symptoms of acute optic neuritis were analyzed retrospectively, including whole-brain contrast-enhanced 3D T1-weighted black-blood and dedicated orbital coronal 2D or 3D contrast-enhanced T1-weighted Dixon sequences. Two neuroradiologists assessed the images for overall image quality, artifacts, diagnostic confidence, and visual contrast enhancement. Furthermore, the standardized contrast-to-noise ratio was calculated. The final diagnosis of acute optic neuritis was established on the basis of clinical presentation, visually evoked potentials, and optical coherence tomography.

RESULTS

Thirty of 51 patients were diagnosed with acute optic neuritis. Of those, 21 showed contrast-enhancing lesions in the optic nerves, similarly detectable on contrast-enhanced T1-weighted Dixon and contrast-enhanced T1-weighted black-blood images. Thus, the accuracy for each sequence was identical, with a resulting sensitivity of 70% and specificity of 90% or 100% (depending on the reader). Overall image quality, diagnostic confidence, visual contrast enhancement, and artifacts were rated similarly in contrast-enhanced 3D T1-weighted black-blood and dedicated orbital contrast-enhanced T1-weighted Dixon sequences. There was no significant difference (P = .27) in the mean standardized contrast-to-noise ratio between contrast-enhanced T1-weighted black-blood (1.76 ± 1.07) and contrast-enhanced T1-weighted Dixon (2.29 ± 2.49) sequences.

CONCLUSIONS

Contrast-enhanced 3D T1-weighted black-blood imaging is comparable in accuracy and qualitative/quantitative features with dedicated orbital contrast-enhanced T1-weighted Dixon imaging for the detection of acute optic neuritis. Therefore, when used, it has the potential to considerably shorten total patient imaging time.

Optical coherence tomography for detection of asymptomatic optic nerve lesions in clinically isolated syndrome

Objective

To evaluate the ability of intereye retinal thickness difference (IETD) measured by optical coherence tomography (OCT) to detect asymptomatic optic nerve involvement in clinically isolated syndrome (CIS).

Methods

We conducted a cross-sectional study of patients who recently presented a CIS (≤4.5 months). All patients underwent OCT and brain/optic nerve MRI. Optic nerve involvement was defined clinically (episode of optic neuritis [ON] or not) and radiologically (optic nerve hypersignal on 3D double inversion recovery [3D-DIR]). We evaluated the sensitivity and specificity of previously published IETD thresholds and report the observed optimal thresholds for identifying symptomatic optic nerve involvement but also for identifying asymptomatic optic nerve involvement (optic nerve hypersignal without ON history). Primary outcomes were ganglion cell–inner plexiform layer (GC-IPL) and peripapillary retinal nerve fiber layer IETD.

Results

The study group consisted of 130 patients. In the CIS with ON group, 3D-DIR showed a hypersignal in all 41 symptomatic optic nerves and in 11 asymptomatic optic nerves. In the CIS without ON group, 3D-DIR showed a unilateral optic nerve hypersignal in 22 patients and a bilateral optic nerve hypersignal in 7 patients. For the detection of symptomatic and asymptomatic optic nerve lesion, GC-IPL IETD had better performance. We found an optimal GC-IPL IETD threshold ≥2.83 µm (sensitivity 88.2, specificity 83.3%) for the detection of symptomatic lesions and an optimal GC-IPL IETD ≥1.42 µm (sensitivity 89.3%, specificity 72.6%) for the detection of asymptomatic lesions.

Conclusions

Detection of asymptomatic optic nerve lesions in CIS requires lower IETD thresholds than previously reported. GC-IPL IETD represents an alternative biomarker to MRI for the detection of asymptomatic optic nerve lesions.

Classification of evidence

This study provides Class I evidence that OCT accurately identifies asymptomatic optic nerve involvement in patients with CIS.

Asymptomatic optic nerve lesions: An underestimated cause of silent retinal atrophy in MS

OBJECTIVE

To evaluate the frequency of asymptomatic optic nerve lesions and their role in the asymptomatic retinal neuroaxonal loss observed in multiple sclerosis (MS).

METHODS

We included patients with remitting-relapsing MS in the VWIMS study (Analysis of Neurodegenerative Process Within Visual Ways In Multiple Sclerosis) (ClinicalTrials.gov Identifier: 03656055). Included patients underwent optical coherence tomography (OCT), optic nerve and brain MRI, and low-contrast visual acuity measurement. In eyes of patients with MS without optic neuritis (MS-NON), an optic nerve lesion on MRI (3D double inversion recovery [DIR] sequence) was considered as an asymptomatic lesion. We considered the following OCT/MRI measures: peripapillary retinal nerve fiber layer thickness, macular ganglion cell + inner plexiform layer (mGCIPL) volumes, optic nerve lesion length, T2 lesion burden, and fractional anisotropy within optic radiations.

RESULTS

An optic nerve lesion was detected in half of MS-NON eyes. Compared to optic nerves without any lesion and independently of the optic radiation lesions, the asymptomatic lesions were associated with thinner inner retinal layers (p < 0.0001) and a lower contrast visual acuity (p ≤ 0.003). Within eyes with asymptomatic optic nerve lesions, optic nerve lesion length was the only MRI measure significantly associated with retinal neuroaxonal loss (p < 0.03). Intereye mGCIPL thickness difference (IETD) was lower in patients with bilateral optic nerve DIR hypersignal compared to patients with unilateral hypersignal (p = 0.0317). For the diagnosis of history of optic neuritis, sensitivity of 3D DIR and of mGCIPL IETD were 84.9% and 63.5%, respectively.

CONCLUSIONS

Asymptomatic optic nerve lesions are an underestimated and preponderant cause of retinal neuroaxonal loss in MS. 3D DIR sequence may be more sensitive than IETD measured by OCT for the detection of optic nerve lesions.

Optical coherence tomography: a window to the optic nerve in clinically isolated syndrome

In this study, we aimed to evaluate the association of asymptomatic optic nerve demyelinating lesion in patients presenting a clinically isolated syndrome with the asymptomatic retinal neuro-axonal loss previously reported at clinically isolated syndrome. We prospectively recruited 66 patients presenting a clinically isolated syndrome and 66 healthy control subjects matched according to age and gender. All patients underwent brain magnetic resonance imaging including 3D-double inversion recovery (DIR) sequence, optical coherence tomography examination and visual function evaluation, at 2.5-4.5 months after CIS. Evaluation criteria were presence and length of optic nerve DIR hypersignal, retinal layers (including ganglion cell inner plexiform layer and inner nuclear layer) thickness/volume, and low contrast monocular vision acuity (number of letters correctly identified). All clinically isolated syndrome eyes with past history of optic neuritis (CIS-ON) presented an optic nerve DIR hypersignal. We observed asymptomatic optic nerve DIR hypersignal in 22.2% of clinically isolated syndrome eyes without optic neuritis (CIS-NON). In comparison with healthy control, GCIPL volume (in mm3) was significantly lower in CIS-ON eyes [β (95% confidence interval, CI) = -0.121 (-0.168 to -0.074); P < 0.0001], and to a lesser extent in CIS-NON [β (95% CI) = -0.023 (-0.039 to -0.008); P = 0.004]. In comparison to healthy controls, eyes with asymptomatic optic nerve DIR hypersignal presented significantly lower macular ganglion cell inner plexiform layer volume [β (95% CI) = -0.043 (-0.068 to -0.019); P = 0.001], and eyes without did not [β (95% CI) = -0.016 (-0.034 to 0.003); P = 0.083]. Among CIS-NON, macular ganglion cell inner plexiform layer volume decrease was associated with asymptomatic optic nerve DIR hypersignal independently of optic radiations T2 lesions and primary visual cortex volumes (P = 0.012). Symptomatic optic nerve DIR hypersignal were significantly longer (13.8 ± 6.7 mm) than asymptomatic optic nerve hypersignal (10.0 ± 5.5 mm; P = 0.047). Length of optic nerve DIR hypersignal was significantly associated with thinner inner retinal layers (P ≤ 0.001), thicker inner nuclear layer (P = 0.017) and lower low contrast monocular vision acuity (P < 0.05). Compared to healthy control, low contrast monocular vision acuity was significantly lower in CIS-ON eyes (P < 0.0001) and CIS-NON eyes with (P = 0.03) or without asymptomatic optic nerve DIR hypersignal (P = 0.0005). Asymptomatic demyelinating optic nerve DIR hypersignal at the earliest clinical stage of multiple sclerosis is frequent and associated with asymptomatic retinal neuro-axonal loss reported at clinically isolated syndrome stage. Length of optic nerve DIR hypersignal is a biomarker of retinal neuro-axonal loss and visual disability at clinically isolated syndrome stage. Visual disability of clinically isolated syndrome eyes without clinical and subclinical optic nerve involvement might be due to missed optic nerve lesions on MRI. At the earliest clinical stage of multiple sclerosis, our results support considering optical coherence tomography as a window to the optic nerve rather than to the brain.

Optic nerve double inversion recovery hypersignal in patients with clinically isolated syndrome is associated with asymptomatic gadolinium-enhanced lesion

Background:

Optic nerve involvement is not considered in dissemination in space (DIS) or time (DIT) of multiple sclerosis (MS) lesions.

Objectives:

To evaluate frequency of optic nerve involvement using three-dimensional (3D)-double inversion recovery (DIR) sequence in clinically isolated syndrome (CIS) and to measure its relationship with DIS and DIT (2010 and 2017 McDonald criteria).

Methods:

From November 2013 to August 2016, 57 CIS patients underwent 3T-magnetic resonance imaging (3T-MRI) including 3D-DIR sequence and optical coherence tomography (OCT) at 3 months after CIS. We assessed signal abnormalities of the optic nerves on DIR sequence and collected data for DIS and DIT criteria according to 2010 and 2017 McDonald criteria.

Results:

Among the 57 recruited patients, the presence of ⩾1 DIR hypersignal in optic nerve was observed in 36 (63%; 48 optic nerves) including asymptomatic hypersignal in 22 (38.5%; 25 optic nerves). Optic nerve involvement was significantly associated with DIT ( p = 0.006) and MS according to 2010 criteria ( p = 0.01) but was not significantly associated with presence of DIS criteria according to 2010 and 2017 McDonald criteria. We identified a significant ( p < 0.001) temporal peripapillary retinal nerve fiber layer thinning on eyes with optic nerve involvement versus healthy controls.

Conclusions:

Optic nerve involvement is very frequent at the earliest clinical stage of MS. It is associated with the presence of asymptomatic gadolinium-enhancement and retinal axonal loss and may reflect the inflammatory disease activity level.

3D double inversion recovery MR imaging: Clinical applications and usefulness in a wide spectrum of central nervous system diseases

Double inversion recovery (DIR) imaging provides two inversion pulses that attenuate signals from cerebrospinal fluid and normal white matter. This review was undertaken to describe the principle of the DIR sequence, the clinical applications of 3D DIR in various central nervous system diseases and the clinical benefits of the 3D DIR compared with those of other MR sequences. 3D DIR imaging provides better lesion conspicuity and topography than other MR techniques. It is particularly useful for diagnosing the following disease entities: cortical and subcortical abnormalities such as multiple sclerosis, cortical microinfarcts and cortical development anomalies; sulcal abnormalities such as meningitis and subacute/chronic subarachnoid hemorrhage; and optic neuritis caused by multiple sclerosis or neuromyelitis optica.

Retinal layer segmentation in multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Structural retinal imaging biomarkers are important for early recognition and monitoring of inflammation and neurodegeneration in multiple sclerosis. With the introduction of spectral domain optical coherence tomography (SD-OCT), supervised automated segmentation of individual retinal layers is possible. We aimed to investigate which retinal layers show atrophy associated with neurodegeneration in multiple sclerosis when measured with SD-OCT.

METHODS

In this systematic review and meta-analysis, we searched for studies in which SD-OCT was used to look at the retina in people with multiple sclerosis with or without optic neuritis in PubMed, Web of Science, and Google Scholar between Nov 22, 1991, and April 19, 2016. Data were taken from cross-sectional cohorts and from one timepoint from longitudinal studies (at least 3 months after onset in studies of optic neuritis). We classified data on eyes into healthy controls, multiple-sclerosis-associated optic neuritis (MSON), and multiple sclerosis without optic neuritis (MSNON). We assessed thickness of the retinal layers and we rated individual layer segmentation performance by random effects meta-analysis for MSON eyes versus control eyes, MSNON eyes versus control eyes, and MSNON eyes versus MSON eyes. We excluded relevant sources of bias by funnel plots.

FINDINGS

Of 25 497 records identified, 110 articles were eligible and 40 reported data (in total 5776 eyes from patients with multiple sclerosis [1667 MSON eyes and 4109 MSNON eyes] and 1697 eyes from healthy controls) that met published OCT quality control criteria and were suitable for meta-analysis. Compared with control eyes, the peripapillary retinal nerve fibre layer (RNFL) showed thinning in MSON eyes (mean difference -20·10 μm, 95% CI -22·76 to -17·44; p<0·0001) and in MSNON eyes (-7·41 μm, -8·98 to -5·83; p<0·0001). The macula showed RNFL thinning of -6·18 μm (-8·07 to -4·28; p<0·0001) in MSON eyes and -2·15 μm (-3·15 to -1·15; p<0·0001) in MSNON eyes compared with control eyes. Atrophy of the macular ganglion cell layer and inner plexiform layer (GCIPL) was -16·42 μm (-19·23 to -13·60; p<0·0001) for MSON eyes and -6·31 μm (-7·75 to -4·87; p<0·0001) for MSNON eyes compared with control eyes. A small degree of inner nuclear layer (INL) thickening occurred in MSON eyes compared with control eyes (0·77 μm, 0·25 to 1·28; p=0·003). We found no statistical difference in the thickness of the combined outer nuclear layer and outer plexiform layer when we compared MSNON or MSON eyes with control eyes, but we found a small degree of thickening of the combined layer when we compared MSON eyes with MSNON eyes (1·21 μm, 0·24 to 2·19; p=0·01).

INTERPRETATION

The largest and most robust differences between the eyes of people with multiple sclerosis and control eyes were found in the peripapillary RNFL and macular GCIPL. Inflammatory disease activity might be captured by the INL. Because of the consistency, robustness, and large effect size, we recommend inclusion of the peripapillary RNFL and macular GCIPL for diagnosis, monitoring, and research.

FUNDING

None.

How Common Is Signal-Intensity Increase in Optic Nerve Segments on 3D Double Inversion Recovery Sequences in Visually Asymptomatic Patients with Multiple Sclerosis?

BACKGROUND AND PURPOSE

In postmortem studies, subclinical optic nerve demyelination is very common in patients with MS but radiologic demonstration is difficult and mainly based on STIR T2WI. Our aim was to evaluate 3D double inversion recovery MR imaging for the detection of subclinical demyelinating lesions within optic nerve segments.

MATERIALS AND METHODS

The signal intensities in 4 different optic nerve segments (ie, retrobulbar, canalicular, prechiasmatic, and chiasm) were evaluated on 3D double inversion recovery MR imaging in 95 patients with MS without visual symptoms within the past 3 years and in 50 patients without optic nerve pathology. We compared the signal intensities with those of the adjacent lateral rectus muscle. The evaluation was performed by a student group and an expert neuroradiologist. Statistical evaluation (the Cohen κ test) was performed.

RESULTS

On the 3D double inversion recovery sequence, optic nerve segments in the comparison group were all hypointense, and an isointense nerve sheath surrounded the retrobulbar nerve segment. At least 1 optic nerve segment was isointense or hyperintense in 68 patients (72%) in the group with MS on the basis of the results of the expert neuroradiologist. Student raters were able to correctly identify optic nerve hypersignal in 97%.

CONCLUSIONS

A hypersignal in at least 1 optic nerve segment on the 3D double inversion recovery sequence compared with hyposignal in optic nerve segments in the comparison group was very common in visually asymptomatic patients with MS. The signal-intensity rating of optic nerve segments could also be performed by inexperienced student readers.

Trans-synaptic degeneration in the optic pathway. A study in clinically isolated syndrome and early relapsing-remitting multiple sclerosis with or without optic neuritis

OBJECTIVE

Increasing evidence suggest that neuronal damage is an early and diffuse feature of Multiple Sclerosis (MS) pathology. Analysis of the optic pathway may help to clarify the mechanisms involved in grey matter damage in MS. Purpose of our study was to investigate the relationship between inflammation and neurodegeneration and to achieve evidence of trans-synaptic degeneration in the optic pathway in MS at clinical onset.

METHODS

50 clinically isolated syndromes/early relapse-onset MS (CIS/eRRMS) with mean disease duration of 4.0±3.5 months, 28 MRI healthy controls (HC) and 31 OCT-HC were studied. Ten patients had optic neuritis at presentation (MSON+), 40 presented with other symptoms (MSON-). MRI examination included 3D-T1, 3D-FLAIR and 3D-DIR sequences. Global cortical thickness (gCTh), pericalcarin CTh (pCTh) and white matter volume (WMV) were analysed by means of Freesurfer on 3D-T1 scans. Optic radiation morphology (OR) and volume (ORV) were reconstructed on the base of the Jülich's Atlas. White matter lesion volume (WMLV), OR-WMLV and percent WM damage (WMLV/WMV = WMLV% and OR-WMLV/ORV = ORWMLV%) were obtained by 3D-FLAIR image segmentation. 3D-DIR sequences were applied to identify inflammatory lesions of the optic nerve. Optic coherence tomography (OCT) protocol included the analysis of global peripapillary retinal nerve fiber layer (g-RNFL) and the 6 fundus oculi's sectors (temporal, T-RNFL; temporal superior, TS-RNFL; nasal superior, NS-RNFL; nasal, N-RNFL; nasal inferior, NI-RNFL, temporal inferior, TI-RNFL). The retina of both eyes was analyzed. The eyes of ON+ were further divided into affected (aON+) or not (naON+).

RESULTS

No difference in CTh was found between CIS/eRRMS and HC, and between MSON+ and MSON-. Moreover, MSON+ and MSON- did not differ for any WM lesion load parameter. The most significant correlations between RNFL thickness and optic radiation WM pathology were found in MSON+. In these patients, the temporal RNFL inversely correlated to ipsilateral optic radiation WM lesion load (T-RNFL: r -0.7, p<0.05; TS-RNFL: r -0.7, p<0.05), while nasal RNFL inversely correlated to contralateral optic radiation WM lesion load (NI: r -0.8, p<0.01; NS-RNFL: r -0.8, p<0.01).

CONCLUSIONS

Our findings suggest that in MSON+ the optic pathway is site of a diffuse pathological process that involves both directly and via trans-synaptic degeneration the RNFL.

A novel imaging technique for better detecting new lesions in multiple sclerosis

We developed a tool that performs longitudinal subtraction of 3D double inversion recovery (DIR) images in follow-up magnetic resonance (MR) examinations of patients with multiple sclerosis. As DIR sequences show a high lesion-to-parenchyma contrast, we hypothesized that such a tool might lead to increased sensitivity for new lesions as well as to speeding up the routine clinical work-up of follow-up MR imaging in multiple sclerosis by directly visualizing new lesions. DIR subtraction images of serial MR examinations were calculated in 106 patients with multiple sclerosis. Existence of new lesions was assessed in three different ways: by standard visual comparison, by FLAIR, and by DIR subtraction maps. A reference standard, to which the single modalities were compared, was defined by combining all information from all readouts and all readers. The presence and number of new lesions were determined and the time needed for analysis measured. Accuracy of detecting overall existence of new lesions using DIR subtraction maps was significantly higher than using visual comparison (96 vs. 86%, p = 0.013) or FLAIR subtraction maps (p < 0.001), with increased sensitivity and higher negative predictive value. Significantly more new lesions were detected when using DIR subtraction maps (p < 0.001). Analyzing subtraction maps took less than a third of the time needed for the standard visual comparison (p = 0.007). Thus, DIR subtraction maps improve the detection of new lesions in a clinical setting both in terms of accuracy and in terms of speed.

Myelin-oligodendrocyte-glycoprotein (MOG) autoantibodies as potential markers of severe optic neuritis and subclinical retinal axonal degeneration

Antibodies against conformation-dependent epitopes of myelin-oligodendrocyte-glycoprotein (MOG-abs) are present in subgroups of neuromyelitis optica spectrum disorder (NMOSD), recurrent optic neuritis (rON), multiple sclerosis (MS), and anti-NMDAR encephalitis. Using optical coherence tomography (OCT) we assessed whether MOG-abs might serve as potential marker of retinal axonal degeneration. We investigated a clinically heterogeneous cohort of 13 MOG-abs-positive patients (4 MOG-abs-positive rON, 4 MOG-abs-positive adult MS, 3 MOG-abs-positive relapsing encephalomyelitis, 2 MOG-abs-positive aquaporin-4-abs-negative NMOSD). As controls, we studied 13 age, sex and ON episode(s)-matched MOG-abs and aquaporin-4-abs-negative (AQP4-abs-negative) MS patients and 13 healthy controls (HC). In addition, we investigated 19 unmatched AQP4-abs-positive MOG-abs-negative NMOSD subjects. Considering all eyes, global pRNFL [in µm, mean (SD)] was significantly reduced in MOG-abs-positive patients [72.56 (22.71)] compared to MOG-abs-negative MS [80.81 (13.55), p = 0.0128], HCs [103.54 (8.529), p = 0.0014] and NMOSD [88.32 (18.43), p = 0.0353]. Non ON eyes from MOG-abs-positive subjects showed significant subclinical atrophy of temporal pRNFL quadrants. Microcystic macular edema (MME) was observed only in eyes of MOG-abs-positive (24%) and AQP4-abs-positive NMOSD (5.6%), but not in MOG-abs-negative MS or HC (p < 0.01). MOG-abs may serve as potential marker of retinal degeneration. Specifically, MOG-abs-related OCT features predominate in temporal pRNFL quadrants (resembling the MS retinal pattern), might be more severe than AQP4-abs-positive NMOSD, indicate subclinical pathology, and may be associated with MME.