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T2/FLAIR Hyperintensity in Mesial Temporal Lobe: Challenging Differential Diagnosis
1Department of Radiology, College of Medicine, Yeungnam University, Daegu, South Korea.
Abstract:
T2/FLAIR hyperintensity in the mesial temporal lobe is the most common MR finding of herpes simplex encephalitis, but may be observed in other infectious and non-infectious diseases. The former includes herpes human virus 6 encephalitis, Japanese encephalitis, and neurosyphilis, and the latter autoimmune encephalitis, gliomatosis cerebri, bilateral or paradoxical posterior cerebral artery infarction, status epilepticus, and hippocampal sclerosis. Thus, T2/FLAIR hyperintensity in the mesial temporal lobe is not a disease-specific magnetic resonance imaging finding, and these conditions must be differentiated to ensure proper treatment. We review diseases that present with T2/FLAIR hyperintensity in the mesial temporal lobe and provide a helpful flow chart based on clinical and radiologic features.
Insights
Mesial temporal lobe T2/FLAIR hyperintensity on MRI is common in herpes simplex encephalitis but also seen in many other conditions. Differentiating these diseases is crucial for effective treatment.
Area of Science:
- Neurology
- Radiology
- Infectious Diseases
Background:
- T2/FLAIR hyperintensity in the mesial temporal lobe is a frequent magnetic resonance imaging (MRI) finding.
- While characteristic of herpes simplex encephalitis, this finding is not disease-specific.
Purpose of the Study:
- To review diseases presenting with mesial temporal lobe T2/FLAIR hyperintensity.
- To provide a diagnostic flowchart based on clinical and radiological features to aid differentiation.
Main Methods:
- Literature review of infectious and non-infectious diseases causing mesial temporal lobe T2/FLAIR hyperintensity.
- Analysis of clinical and radiological characteristics for differential diagnosis.
Main Results:
- Herpes simplex encephalitis, herpes human virus 6 encephalitis, Japanese encephalitis, neurosyphilis, autoimmune encephalitis, gliomatosis cerebri, posterior cerebral artery infarction, status epilepticus, and hippocampal sclerosis can all present with this MRI finding.
- Clinical presentation and specific radiological nuances are key to differentiation.
Conclusions:
- Mesial temporal lobe T2/FLAIR hyperintensity is a non-specific MRI finding.
- Accurate differentiation of various conditions is essential for appropriate patient management and treatment.
