Das visuelle System ist häufig betroffenen bei neuroinflammatorischen
Erkrankungen, sowohl im Sinne einer Optikusneuritis (ON) als auch durch
Läsionen entlang der Sehbahn, z.B. in der Sehstrahlung. Verschiedene
Methoden können sowohl die Struktur als auch die Funktion des visuellen
Systems untersuchen. In diesem Artikel werden die unterschiedlichen
Diagnostikinstrumente mit Fokus auf die klinische Relevanz diskutiert.
Abstract
The visual system is frequently affected in neuroinflammatory diseases. While the
typical clinical manifestation is optic neuritis (ON), lesions along the entire
visual pathway are common. Several paraclinical tests can be used to quantify
abnormalities of the visual pathway in neuroinflammatory disorders. Although an
optic nerve affection is currently not included in the diagnostic criteria of
multiple sclerosis (MS), these tests may be very sensitive to detect
asymptomatic and symptomatic lesions at early diseases stages. Moreover, they
can contribute to the differential diagnosis among neuroinflammatory diseases.
Last, they may play a role in the prognosis of visual deficits, and even of
overall disability.
In this article, we discuss three paraclinical tests: optical coherence
tomography (OCT) of the retina, magnetic resonance imaging (MRI) of the optic
nerve and visual evoked potentials (VEP), including their advantages and
limitations, with a focus on their role in clinical practice.
OCT is a non-invasive, quick imaging technique that measures the thickness of
retinal layers. It can quantify atrophy of the combined ganglion cell- and inner
plexiform layer (GCIPL) and the peripapillary retinal nerve fiber layer (pRNFL)
after ON. Moreover, it can show subclinical atrophy of these layers, especially
in patients with MS. The pattern of atrophy in the OCT can contribute to the
differential diagnosis among neuroinflammatory diseases.
MRI is an imaging method that plays a critical role in the diagnosis and
monitoring of MS. It can capture both symptomatic and asymptomatic lesions along
the entire visual pathway. MRI of the optic nerve needs specific sequences with
fat saturation and possibly (for acute ON) gadolinium. The length and location
of the optic nerve lesions may be useful in the differential diagnosis (e. g. MS
versus neuromyelitis optica spectrum disorders).
VEP is an electrophysiological measure of the afferent visual pathway. In acute
ON, the P100 latency of the VEP may be prolonged, or there may be a conduction
block (absence of P100 wave). In the subacute and chronic phase after ON, VEP
often remain asymmetric/abnormal. Thus, the VEP can be particularly useful in
quantifying subclinical/prior optic nerve affection in neuroinflammatory
diseases. In addition, VEP are possibly also markers of remyelination.
Schlüsselwörter OCT - VEP - MRT - Sehnerv - Optikusneuritis - Multiple Sklerose
Keywords OCT - VEP - MRI - optic nerve - optic neuritis - Multiple Sclerosis
