Assessment of Retinal Nerve Fiber Layer (RNFL) and Retinal Ganglion Cell Layer (RGCL) Thickness in Radiologically Isolated Syndrome (RIS)

Background: Three-thirds of people with radiologically isolated syndrome (RIS) develop multiple sclerosis (MS) within five years following their first brain magnetic resonance imaging (MRI). Subclinical applications of optical coherence tomography (OCT) include measuring the thickness of different retinal layers and monitoring the progression of visual pathway atrophy and neurodegeneration in relation to the progress of the entire brain. Objectives: Our OCT study was conducted in individuals with RIS to evaluate the thickness of the macular retinal nerve fiber layer (mRNFL) and the retinal ganglion cell layer (RGCL). Methods: In this study, 22 patients with RIS and 23 healthy individuals healthy control (HC) were enrolled. The control group and the RIS subjects underwent retinal imaging with OCT. Results: Total mRNFL thickness was 110.34 ± 13.71 μm in the RIS patients and 112.10 ± 11.23 μm in the HC group. Regional analysis of the mRNFL showed that the difference in thickness was more prominent in the superior quadrant. In regards to ganglion cell layer (GCL)++ thickness, the RIS and HCs population showed statistically significant differences in the nasal (P = 0.041), inferior (P = 0.040), and superior (P = 0.045) quadrants. The nasal (P = 0.041) quadrant showed the highest reduction in thickness compared to other regions of the GCL++. Meanwhile, no significant reduction was seen in GCL+ thickness (P-value > 0.05). When the thickness of the retinal layer of the right eye was compared to that of the left eye of the RIS group, no statistically significant differences were found (P-value > 0.05). Conclusions: Compared to the control group, the RIS group had a lower mean thickness of mRNFL and GCL++, indicating retinal neuroaxonal loss.

[Radiologically isolated syndrome: prognosis and predictors of conversion to multiple sclerosis]

Increased sensitivity and availability of magnetic resonance imaging (MRI) in neurological routine practice led to the fact that more and more experts began to encounter changes typical for multiple sclerosis (MS) according to MRI in the absence of anamnestic and clinical indications of damage to the central nervous system (CNS). This nosological form has been defined as a radiologically isolated syndrome (RIS). More and more RIS cases convert to MS (up to 30% in the first 5 years after RIS diagnosis). At the moment, there are no biological markers that allow combining RIS and MS into one pathological process and early treatment with disease-modifying drugs (DMT). Prospective studies are actively being conducted to identify demographic, clinical, neuroimaging and biochemical conversion predictors. The identification of the molecular biological RIS features, combining these changes with MS, is an urgent scientific task and will allow timely initiation of therapy of the pathological process already at the subclinical stage.

The apparently milder course of multiple sclerosis: changes in the diagnostic criteria, therapy and natural history

In the past decade, changes have occurred in the spectrum of multiple sclerosis courses. The natural history of multiple sclerosis appears milder from the first sign of demyelinating disease to the progressive course, probably as a result of an interplay between several factors including changes in the diagnostic criteria, changes in the epidemiology of multiple sclerosis, impact of early and appropriate disease-modifying treatment and improvement of the general state of health in the population. It has been suggested to regard incidental findings of demyelinating lesions in MRI in individuals without any history of clinical symptoms consistent with neurological dysfunction, so-called radiological isolated syndrome, as the initial course of multiple sclerosis. New diagnostic criteria have enabled the multiple sclerosis diagnosis in many patients at the first clinical demyelinating event, clinically isolated syndrome. The remaining patients with clinically isolated syndrome have a more benign prognosis, and for relapsing-remitting multiple sclerosis, the prognosis has become more favourable. Reduced disease activity in patients with relapsing-remitting multiple sclerosis can partly be ascribed to more efficacious new disease-modifying therapies but decrease in disease activity has also be seen in placebo-treated patients in clinical trials. This may be explained by several factors: change in the diagnostic criteria, more explicit inclusion criteria, exclusion of high-risk patients e.g. patients with co-morbidities, and more rigorous definitions of relapses and disease worsening. However, these factors also make the disease course in patients treated with disease-modifying therapies seem more favourable. In addition, change in the therapeutic target to stable disease (no evidence of disease activity = no relapses, no disease worsening and no MRI activity) could by itself change the course in relapsing-remitting multiple sclerosis. The effectiveness of disease-modifying drugs has reduced the transition from relapsing-remitting to secondary progressive multiple sclerosis. The concept of progressive multiple sclerosis has also evolved from two very distinct categories (primary progressive and secondary progressive multiple sclerosis) to a unified category of progressive multiple sclerosis, which can then be split into the categories of active or inactive. Also, an increasing tendency to treat progressive multiple sclerosis with disease-modifying therapies may have contributed to change the course in progressive multiple sclerosis. In conclusion, during the past decade the entire course of multiple sclerosis from the first sign of a demyelinating disorder through the progressive course appears to be milder due to a complex interplay of several factors.

MRI features associated with high likelihood of conversion of radiologically isolated syndrome to multiple sclerosis

Radiologically isolated syndrome (RIS) is the asymptomatic precursor to clinically isolated syndrome, relapsing-remitting multiple sclerosis (MS) or primary progressive MS. RIS is frequently diagnosed when an individual gets an MRI for an unrelated medical issue, such as headache or trauma. Treating RIS patients is controversial, but physicians may be inclined to offer prophylactic treatment for high-risk RIS patients. Identifying imaging and clinical features associated with high likelihood of early clinical conversion may prove helpful to identify a high-risk subset for potential MS therapy. The goal of this paper is to review current literatures to identify imaging and clinical features that predict early (within 5 years) conversion from RIS to MS.

Drug Treatment of Clinically Isolated Syndrome

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system (CNS) that leads to inflammation, demyelination and ultimately axonal degeneration. In most cases, it is preceded by its precursor, clinically isolated syndrome (CIS) with conversion rates to clinically definite MS (CDMS) of roughly 20-75%. Neurologists are therefore faced with the challenge of initiating a disease-modifying therapy (DMT) as early as possible to favorably influence the course of the disease. During the past 20 years, a multitude of drugs have been incorporated into our therapeutic armamentarium for MS and CIS. Choosing the right drug for an individual patient is complex and should be based not only on the drug's overall efficacy to prevent disease progression but also its specific adverse reaction profile, the severity of individual disease courses and, finally, patient compliance in order to adequately weigh associated risks and benefits. Here, we review the available data on the efficacy, safety and tolerability of DMTs tested for CIS and discuss their value regarding a delay of progression to CDMS.

Silent Tumefactive Demyelinating Lesions and Radiologically Isolated Syndrome

Demyelinating lesions larger than 2 cm in diameter, with or without edema, are known as tumefactive demyelinating lesions (TDLs). They constitute a rare inflammatory demyelinating disorder of the central nervous system. TDLs are typically characterized by headaches, cortical symptoms such as aphasia, hemiparesis, hemisensory deficits, seizures, and changes in consciousness. TDLs may occur in patients with or without an established diagnosis of MS or may occur as the initial demyelinating event. They may also be observed during follow-up in patients with MS, neuromyelitis optica, acute disseminated encephalomyelitis, or other autoimmune diseases. Differential diagnosis includes brain tumors, abscess, granulomatous diseases, and vasculitis. In some cases, it may be very difficult to distinguish TDLs from a tumor, such that biopsy might be needed. However, no cases of asymptomatic TDLs have yet been reported in the literature. Hence, in this report, we present a case involving an asymptomatic TDL detected incidentally during magnetic resonance imaging in an 18-year-old man. The patient did not develop any symptoms during the 1-year follow-up period. During follow-up, the patient was diagnosed with a radiologically isolated syndrome. TDLs have not previously been identified as radiologically isolated syndrome. Thus, reporting similar cases in the future will help in further understanding this phenomenon.

Radiologically isolated syndrome in children: Current knowledge and future directions

As the use of magnetic resonance imaging (MRI) grows in clinical practice, clinicians are increasingly faced with the difficult task of interpreting the significance of incidental findings on brain MRI. Among individuals found to have incidental brain MRI findings, a small number have white matter abnormalities on MRI that resemble the demyelinating lesions of multiple sclerosis (MS) in the absence of a history of relevant clinical symptoms. This has been termed radiologically isolated syndrome (RIS). Recent years have seen growing interest in RIS, with observational studies that have specifically focused on answering questions regarding the subsequent risk of future clinical events and diagnosis of MS in adults and children with these findings. Given the high rate of subsequent clinical events seen in adult studies, knowledge related to RIS in children is paramount, particularly given the higher disease activity and burden in children with MS. This review examines this question, providing an overview of RIS with a focus on its significance in children including current definitions, its association with MS, and knowledge related to therapeutic interventions for RIS. We conclude with suggestions for an approach to assessment of and subsequent surveillance in children fulfilling criteria for RIS and directions for future study.