ABSTRACT. 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. MRI is the most sensitive imaging technique to depict brain lesions as altered signal intensities. Most of the lesions are demonstrated as hyperintensities on T 2 weighted and fluid-attenuated inversion-recovery (FLAIR) MR images, and the signal intensity itself is non-specific. Characteristic distribution of lesions and associated imaging findings, however, can suggest the diagnosis or narrow the differential diagnosis. Bilateral temporal lobe hyperintensity (BTH) is a commonly observed finding on MRI in different neurological disorders. We considered BTH as increased signal intensity on T 2 weighted or FLAIR MR images involving the grey or white matter or both. Compared with fast spin-echo T 2 weighted sequence, FLAIR has greater sensitivity for detection of BTH because of suppression of the cerebrospinal fluid (CSF) signal with preservation of T 2 characteristics [1]. Several neurological disorders have a distinctive propensity to involve the temporal lobes. The spectrum includes infective, epileptic syndrome, neurodegenerative, neoplastic, metabolic, dysmyelinating, vascular and paraneoplastic disorders. Associated MRI features like gyral haemorrhages, hippocampal, mamillary body and forniceal atrophy, basal ganglia (BG) hyperintensity, temporal lobe cysts, pachygyria-agyria complex and lacunar infarcts help in narrowing the differential diagnosis. Advanced MRI including diffusion-weighted imaging (DWI), susceptibility-weighted imaging (SWI) and MR spectroscopy (MRS) have an added value. Knowledge of key MRI features in the appropriate clinical setting and lab parameters can help to reach the definitive diagnosis. We retro...

Idiopathic hypoparathyroidism can rarely present with extensive spondyloarthropathic changes that closely resemble ankylosing spondylitis, diffuse idiopathic skeletal hyperostosis, or fluorosis. Clinical presentation of the patient, typical laboratory parameters, and radiological findings aid in their differential diagnosis. Extensive spondyloarthropathy with normal sacroiliac joints in patients with neuromuscular symptoms like tetany, paresthesia, and hypocalcemia should raise the possibility of this entity.

We describe MRI findings in a fatal case of culture proven Salmonella typhi-associated encephalopathy. MRI findings included symmetrical diffuse abnormal signal in centrum semiovale, periventricular and deep white matter, splenium of corpus callosum and cerebellar deep white matter with central area of restricted diffusion. There was no contrast enhancement, significant edema or mass effect. Previous literature is also reviewed for imaging findings in Salmonella associated encephalopathy.

Reversible cerebral vasoconstriction syndrome is a rare clinical syndrome characterized by sudden thunderclap headache often an under diagnosed neurological emergency. It is often provoked by postpartum state or exposure to provocative drugs. We report a rare case of Rizatriptan-induced reversible cerebral vasoconstriction syndrome presenting with thunderclap headache and paraparesis with complete recovery of neurological and imaging findings.

Congenital duplication of facial nerve is a very rare anomaly commonly associated with inner and middle ear anomalies. There can be duplication of mastoid, tympanic, or labyrinthine segments. We describe duplication of mastoid segment of facial nerve in a young female who also showed middle ear anomalies and external auditory canal atresia.