Dysembryoplastic neuroepithelial tumor with atypical presentation: MRI and diffusion tensor characteristics.

We report the neuroimaging findings of a 26-year-old female patient with a biopsy-proven dysembryoplastic neuroepithelial tumor (DNET). DNETs are an uncommon, usually benign, glial-neural cortical neoplasm of children and young adults who typically present with intractable seizures. DNETs may occur in any region of the supratentorial cortex, but have a predilection for the temporal lobes.

Anatomic olfactory structural abnormalities in congenital smell loss: magnetic resonance imaging evaluation of olfactory bulb, groove, sulcal, and hippocampal morphology.

Background And Purpose: There are 2 groups of patients with congenital smell loss: group 1 (12% of the total), in which patients exhibit a familial smell loss in conjunction with severe anatomical, somatic, neurological, and metabolic abnormalities such as hypogonadotropic hypogonadism; and a larger group, group 2 (88% of the total), in which patients possess a similar degree of smell loss but without somatic, neurological, or anatomical abnormalities or hypogonadism. Both groups are characterized by similar olfactory dysfunction, and both have been reported to have absent or decreased olfactory bulbs and grooves, which indicates some overlap in olfactory pathophysiology and anatomy. The purpose of this study was to evaluate patients with congenital smell loss, primarily among group 2 patients, comparing brain magnetic resonance imaging (MRI) results in patients with types of hyposmia.

Taste and smell function in chronic disease: a review of clinical and biochemical evaluations of taste and smell dysfunction in over 5000 patients at The Taste and Smell Clinic in Washington, DC.

Purpose: To describe systematic methods developed over 40 years among over 5000 patients at The Taste and Smell Clinic in Washington, DC to evaluate taste and smell dysfunction.

Materials And Methods: A tripartite methodology was developed. First, methods to determine clinical pathology underlying the multiple disease processes responsible for taste and smell dysfunction were developed.

Neuroimaging of a pilocytic astrocytoma with anaplastic features and diffusion tensor imaging characteristics.

We report the MRI findings of an adult patient with a (rare in adults) biopsy-proven pilocytic astrocytoma with anaplastic features. Diffusion tensor imaging may potentially provide information on cell proliferation, vascularity, and fiber destruction, which can have implications for treatment and prognosis. In this case, tractography and fractional anisotropy maps demonstrated displacement of adjacent parenchyma and relatively intact fractional anisotropy, suggesting a pilocytic rather than an anaplastic astrocytoma.

Olfactory Hallucinations without Clinical Motor Activity: A Comparison of Unirhinal with Birhinal Phantosmia.

Olfactory hallucinations without subsequent myoclonic activity have not been well characterized or understood. Herein we describe, in a retrospective study, two major forms of olfactory hallucinations labeled phantosmias: one, unirhinal, the other, birhinal. To describe these disorders we performed several procedures to elucidate similarities and differences between these processes.

Morphological changes of olfactory bulbs and grooves: initial report of supernumerary olfactory bulbs.

Background: Observations and measurements of olfactory structures in humans have been difficult and not of common neuroradiological interest. Because of our interest in olfaction, we have studied the presence, size, and function of these structures in normal subjects and in patients with smell loss.

Methods: Magnetic resonance imaging studies of brain were performed in 220 consecutive patients in our medical center for a variety of clinical neurological investigations.

Neuroimaging of tumefactive multiple sclerosis with atypical features.

Tumefactive demyelinating lesions or tumefactive multiple sclerosis (TMS) constitute a unique presentation of demyelinating disease that frequently mimics intracranial neoplasm, infection or other, nondemyelinating intracranial pathology. Consequently, these lesions, which are larger than typical multiple sclerosis plaques and are generally characterized by certain MRI features including edema and incomplete ring enhancement, pose a serious diagnostic challenge that frequently prompts biopsy in initial evaluation. Biopsy can be averted when imaging features for TMS are seen on MRI.

Narrowing of Meckel's cave and cavernous sinus and enlargement of the optic nerve sheath in Pseudotumor Cerebri.

Objective: Pseudotumor cerebri (PTC) is a clinical entity of uncertain etiology associated with several subtle findings on magnetic resonance imaging (MRI) including posterior flattening of the globes, enlargement of the optic nerve sheath (ONS), empty sella sign. We aimed to characterize the incidence of and significance of 2 novel MRI findings: narrowing of Meckel's cave and of cavernous sinus.

Methods: Forty-six patients with a condition diagnosed as PTC based on clinical history were retrospectively reviewed, and their MRI studies were assessed for previously reported imaging findings associated with PTC.

Orbital plasmablastic lymphoma with remission following chemotherapy.

We report the case of a middle-aged HIV-positive man who presented with proptosis and retro-ocular pain. On CT and MR imaging, a retro-orbital enhancing mass was seen, and PET/CT revealed this lesion as well as a similarly characterized mass in the nasopharynx to be hypermetabolic. Biopsy and subsequent pathological characterization revealed this mass to be plasmablastic lymphoma (PBL), a rare form of non-Hodgkin's lymphoma associated with HIV-infection.

Carbonic anhydrase I, II, and VI, blood plasma, erythrocyte and saliva zinc and copper increase after repetitive transcranial magnetic stimulation.

Introduction: Repetitive transcranial magnetic stimulation (rTMS) has been used to treat symptoms from many disorders; biochemical changes occurred with this treatment. Preliminary studies with rTMS in patients with taste and smell dysfunction improved sensory function and increased salivary carbonic anhydrase (CA) VI and erythrocyte CA I, II. To obtain more information about these changes after rTMS, we measured changes in several CA enzymes, proteins, and trace metals in their blood plasma, erythrocytes, and saliva.

Improvement in smell and taste dysfunction after repetitive transcranial magnetic stimulation.

Background: Olfactory and gustatory distortions in the absence of odors or tastants (phantosmia and phantageusia, respectively) with accompanying loss of smell and taste acuity are relatively common symptoms that can occur without other otolaryngologic symptoms. Although treatment of these symptoms has been elusive, repetitive transcranial magnetic stimulation (rTMS) has been suggested as an effective corrective therapy.

Objective: The objective of the study was to assess the efficacy of rTMS treatment in patients with phantosmia and phantageusia.

Bilateral and independent Broca areas confirmed by Wada test and functional magnetic resonance imaging.

Accurate preoperative evaluation of language dominance is critical when evaluating potential patients for temporal lobe epilepsy surgery. Although most people have left-sided language dominance, a minority of patients have been described with either bilateral or right hemispheric dominance. We present a patient with right temporal lobe epilepsy who presented with bilateral and functionally independent Broca areas, as confirmed by Wada testing and functional magnetic resonance imaging.

Brain gamma-aminobutyric acid changes in stiff-person syndrome.

Background: Patients with stiff-person syndrome (SPS) have circulating antibodies against glutamic acid decarboxylase, the rate-limiting enzyme responsible for the synthesis of gamma-aminobutyric acid (GABA). Although the patients' symptoms of stiffness and unexpected spasms can be explained on the basis of reduced or impaired inhibitory neurotransmitters, such as GABA, it is unclear whether the level of GABA in the brains of these patients is reduced and, if so, whether the reduction is due to anti-glutamic acid decarboxylase antibodies.

Objective: To measure GABA levels in the brains of patients with SPS.

Brain gamma-aminobutyric acid levels are decreased in patients with phantageusia and phantosmia demonstrated by magnetic resonance spectroscopy.

Background: Olfactory and gustatory hallucinations (phantosmias and phantageusias, respectively) are sensory distortions that commonly follow losses of olfactory and gustatory acuity (hyposmia and hypogeusia, respectively). The biochemical basis of these hallucinations is unclear. Functional magnetic resonance imaging has been used previously to demonstrate widespread and robust central nervous system (CNS) activation to memories of these sensory distortions in patients with these symptoms.

Rapid modulation of GABA in sensorimotor cortex induced by acute deafferentation.

Recovery of function after acute injury to the central nervous system may be controlled by the availability of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the cerebral cortex. Acute lesions as well as manipulation of sensory inputs can lead to rapid reorganization of the cerebral cortex, occurring within minutes to hours. Reduction of cortical inhibitory tone through a decrease in the availability of GABA has been suggested as a possible mechanism; however, the degree and temporal course of the changes in brain GABA are not known.

Functional MRI of congenital hyposmia: brain activation to odors and imagination of odors and tastes.

Purpose: Our goal was to use functional MRI (fMRI) to define brain activation in response to odors and imagination ("memory") of odors and tastes in patients who never recognized odors (congenital hyposmia).

Method: Functional MR brain scans were obtained in nine patients with congenital hyposmia using multislice echo planar imaging (EPI) in response to odors of amyl acetate, menthone, and pyridine and to imagination ("memory") of banana and peppermint odors and to salt and sweet tastes. Functional MR brain scans were compared with those in normal subjects and patients with acquired hyposmia.

Impaired brain GABA in focal dystonia.

Patients with task-specific dystonia (writer's cramp) have impaired cortical inhibition likely arising from striatal dysfunction. However, the levels of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) in the brains of these patients are not known. In this study, we evaluated 7 patients with right-sided focal, task-specific dystonia and 17 normal control subjects.