Clinico-radiological spectrum of bilateral temporal lobe hyperintensity: a retrospective review

Bilateral temporal lobe hyperintensity (BTH) is a commonly encountered MRI finding in a wide spectrum of clinical conditions and often poses a diagnostic challenge to the radiologist. The purpose of this paper is to elucidate several diseases that manifest as BTH on MRI, based on a retrospective review of cranial MRI of 65 cases seen in our institution between October 2007 and September 2010. We found BTH in different clinical scenarios that included infective diseases (herpes simplex virus, congenital cytomegalovirus infection), epileptic syndrome (mesial temporal sclerosis), neurodegenerative disorders (Alzheimer's disease, frontotemporal dementia, Type 1 myotonic dystrophy), neoplastic conditions (gliomatosis cerebri), metabolic disorders (mitochondrial encephalopathy, lactic acidosis and stroke-like episodes, Wilson's disease, hyperammonemia), dysmyelinating disease (megalencephalic leukoencephalopathy with subcortical cysts), and vascular (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) and paraneoplastic (limbic encephalitis) disorders. The conventional MRI findings with advanced MRI such as diffusion-weighted imaging, susceptibility-weighted imaging and MR spectroscopy along with laboratory results are potentially helpful in distinguishing the different clinical conditions and thus affect the early diagnosis and clinical outcome.