John L. Go

Imaging of Neurocysticercosis

Neurocysticercosis (NCC) is an infection of the central nervous system by the Taenia solium larvae, and is the most common cause of acquired epilepsy in endemic regions. The natural history of parenchymal NCC lesions can be divided into 4 stages with unique imaging and clinical features. Evaluation of cysticerci is challenging on conventional magnetic resonance (MR) imaging and computed tomography, and is significantly improved with MR cysternography techniques. Differentiation of NCC lesions from metastatic disease and pyogenic abscesses can be improved with advanced MR imaging including (1)H nuclear MR spectroscopy, diffusion-weighted imaging, and MR perfusion imaging.

The trigeminal nerve.

The trigeminal nerve is the largest of the cranial nerves, serving as a major conduit for sensory information from the head and neck and primarily providing motor innervation to the muscles of mastication. An understanding of the pathologic processes that may involve this nerve requires a detailed knowledge of its origin within the brain stem as well as its course intracranially. This article describes the neuroanatomy of the nerve and divides it into its various segments to provide a differential diagnosis of common and some uncommon pathologic processes.

MRI of Cranial Nerve Enhancement

OBJECTIVE In this pictorial essay, we review the MR appearance of cranial nerve enhancement in a variety of entities including neoplastic, infectious, and idiopathic diseases. CONCLUSION MRI with contrast enhancement is a valuable tool for detecting and characterizing disease of the cranial nerves. Abnormal cranial nerve enhancement on MRI may sometimes be the first or only indication of an underlying disease process.

Intracerebral Whipple's disease diagnosed by stereotactic biopsy: a case report and review of the literature.

OBJECTIVE AND IMPORTANCE This case demonstrates the rare occurrence of intracerebral Whipples disease in a patient lacking classic systemic manifestations of the disease. Because of the nonspecific presentation and the typically deep-seated location of cerebral lesions in these patients, definitive diagnosis is frequently problematic. We present the first reported use of stereotaxy-guided brain biopsy to confirm the diagnosis of isolated intracranial Whipples disease. CLINICAL PRESENTATION The patient was a 36-year-old man who presented with a 4-month history of progressive lethargy, hypersomnia, behavioral changes, and weight gain. The results of the physical examination were remarkable only for findings of hypogonadism. Subsequent laboratory evaluation confirmed the diagnosis of hypogonadotrophic hypogonadism, with low levels of testosterone, luteinizing hormone, cortisol, and prolactin. INTERVENTION A magnetic resonance image of the brain demonstrated hyperintense lesions on T2-weighted images in the regions of the right fornix, hypothalamus, and putamen that subsequently enhanced with intravenously administered contrast medium. A biopsy was then obtained from the right putaminal lesion under stereotactic guidance. Histopathological analysis of the tissue revealed findings consistent with intracerebral Whipples disease that were subsequently confirmed using electron microscopy. CONCLUSION Intracerebral Whipples disease should be included in the differential diagnosis of patients presenting with progressive dementia and cognitive decline. In these patients, lesions have typically been observed in the hypothalamus, cingulate gyrus, basal ganglia, insular cortex, and cerebellum. As evidenced by our case, stereotaxy affords clinicians the attractive option of a minimally invasive technique by which to obtain tissue from such deep-seated areas. A review of this rare neurosurgical entity is presented.

Imaging of the pituitary and parasellar region

The pituitary is part of a chain of enormous biologic amplification, which is regulated by a small amount of releasing factors in the portal blood from the hypothalamus. The pituitary is a master gland that regulates a number of hormones. A subtle abnormality in the pituitary can cause significant changes in body metabolism. Because the pituitary glands are small structures, high-resolution imaging techniques are required to satisfactorily evaluate the gland. It is imperative for the radiologist to be familiar with the anatomy, physiology, and pathology of the pituitary gland, which provides a solid foundation for accurate interpretation of the imaging studies of the pituitary gland.

Perfusion and permeability MR imaging of gliomas.

Conventional contrast-enhanced MR imaging is the current standard technique for the diagnosis and treatment evaluation of gliomas and other brain neoplasms. However, this method is quite limited in its ability to characterize the complex biology of gliomas and so there is a need to develop more quantitative imaging methods. Perfusion and permeability MR imaging are two such techniques that have shown promise in this regard. This review will highlight the underlying principles, applications, and pitfalls of these evolving advanced MRI methods.

Radiographic assessment of cranial gunshot wounds.

Though advances in MRI will undoubtedly increase its use, particularly in the subacute period, CT will likely continue its primary role in the management of these injuries in the foreseeable future. The spectrum of imaging features of cranial gunshot injuries is vast, because they encompass all of the findings encountered in closed head injury in addition to the wide variety of problems associated with penetration. Thus, only a brief summary of the many varied aspects of this complex problem is presented here as a review of the more salient issues.

Cranial nerve XII: the hypoglossal nerve.

The hypoglossal nerve, cranial nerve XII, is the motor supply of the tongue. An understanding of the intracranial and extracranial components is fundamental in the evaluation of hypoglossal pathology. The following discussion of the evaluation of the hypoglossal nerve will involve the embryology, anatomy, clinical basis, and imaging techniques with pathologic correlations.

Imaging of sequelae of head trauma.

The imaging of head trauma has been one of the fundamental cornerstones of neuroradiology. As the practice of neuroimaging has matured, great strides have been made in the diagnostic as well as prognostic armamentarium available to physicians. Given the vast diversity of trauma mechanisms and clinical pathways, new advanced imaging technologies have had a lasting impact on the detection, description, and depiction of head trauma. Furthermore, these new tools are allowing the imaging specialist to function not only as an interpreter of what is seen but as a 21st century radiographic oracle. We present a comprehensive review of the imaging findings of sequlae of traumatic brain injury and the growing correlation of new neuroimaging techniques and neurotraumatic outcomes.

Magnetic resonance imaging of infectious meningitis and ventriculitis in adults.

Abstract Magnetic resonance imaging findings of meningitis are usually nonspecific with respect to the causative pathogen because the brain response to these insults is similar in most cases. In this article, we will use a few representative cases to describe the characteristic magnetic resonance findings of meningitis and its complications, including ventriculitis.