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John D Port

Publications and source records attributed to John D Port.

12 recordsLinked to original sources
PubMed2006

Unusual malignant glioneuronal tumors of the cerebrum of adults: a clinicopathologic study of three cases.

Malignant glioneuronal tumors of the brain are rare and poorly characterized. Herein, we report the clinicopathologic features of three examples with unusual morphologies including both glial and neuronal differentiation. Hematoxylin and eosin-stained slides were reviewed in all cases. Immunohistochemical stains were performed on formalin-fixed, paraffin-embedded sections. Transmission electron microscopy (EM) was performed on both formalin-fixed (n=1) and paraffin embedded tissue (n=2). The immunogold technique for localization of GFAP was also performed. Two patients were male and one was female, age 66, 84, and 34 years, respectively. Radiologic studies demonstrated hyperdensity on CT (n=3), multicentricity (n=2), and a cortical based solid component with a cystic extension into underlying white matter (n=2). At surgery, all three tumors were superficial and relatively circumscribed. Histologically, they were composed of large epithelioid cells (n=3), spindle cells (n=1), and poorly differentiated smaller cells with high nuclear/cytoplasmic ratios (n=1). Brisk mitotic activity and coagulative non-palisading necrosis were present in all cases. The tumors were immunopositive for GFAP (n=3), S-100 (n=3), synaptophysin (n=3), chromogranin (n=3), Neu-N (n=2), and neurofilament protein (n=2). Stains for EMA were negative. EM demonstrated convincing neurosecretory granules in one case, some in filament-containing cells immunogold labeled for GFAP. Two patients expired 3-5 weeks after surgery. True malignant neoplasms with glial and neuronal differentiation do occur in the central nervous system of adults and may pursue a highly aggressive course. The use of minimal diagnostic criteria, e.g., immunoreactivity for a single antigen like neurofilament protein, may not be sufficient and should be discouraged.

Adult↗
PubMed2006

A magnetic resonance spectroscopy investigation of obsessive-compulsive disorder and anxiety.

The aim of the current study was to use proton magnetic resonance spectroscopy (MRS) to investigate potential irregularities in neurochemical compounds in obsessive-compulsive disorder (OCD) and the extent to which these irregularities are related to state anxiety. Single voxel MRS was used to image the head of the caudate nucleus (HOC) and orbitofrontal white matter (OFWM) bilaterally in adult patients with OCD and a control group. The results indicated that patients with OCD had increased levels of a combined measure of glutamate and glutamine (Glx/Cr) and N-acetyl-l-aspartic acid (NAA/Cr) relative to creatine in the right OFWM and reduced levels of myo-inositol relative to creatine (mI/Cr) in the HOC bilaterally. Correlational analyses indicated that Glx/Cr in the OFWM was related to OCD symptoms, while mI/Cr in the HOC was related to trait and/or state anxiety. Reanalysis of the significant group differences controlling for state anxiety symptoms erased three of the four group differences. These results are discussed in context of the methodological difficulties facing this area of research.

Adult↗
PubMed2005

Imaging features of copper deficiency myelopathy: a study of 25 cases.

Acquired copper deficiency presents with a spastic gait and sensory ataxia. Spinal cord magnetic resonance imaging (MRI) in patients with copper deficiency myelopathy may show increased T2 signal, most commonly in the dorsal midline cervical and thoracic cord. These imaging findings may be reversible with normalization of serum copper. The clinical and imaging picture is very similar to the subacute combined degeneration seen in patients with vitamin B12 deficiency. Neuroradiologists should consider this possibility when a long segment of symmetric dorsal spinal cord T2-hyperintensity is identified.

Adult↗
PubMed2005

Imaging the brachial plexus.

Imaging the brachial plexus is challenging because of the complex anatomy of the region and the wide variety of pathology that can affect it. For the purpose of imaging, it is helpful to divide traumatic and nontraumatic entities affect-ing the brachial plexus. Improvements in imaging technology, including multidetector CT for CT myelography and the availability of full-field-strength MRI systems with fast gradients and dedicated surface coils for optimal spatial resolution, have led to more accurate prospective diagnoses and improved aid for neurosurgical planning for traumatic and nontraumatic brachial plexopathies. CT myelography is the current gold standard for the diagnosis of nerve root avulsions affecting the brachial plexus. MRI is the preferred modality for nontraumatic brachial plexopathy. Other modalities, such as US and PET, have a limited role in the evaluation of brachial plexus pathology. High-quality, high-resolution CT and MRI remain the mainstays for imaging the brachial plexus.

Brachial Plexus↗
PubMed2005

Magnetic resonance spectroscopic studies of pediatric mood disorders: a selective review.

PURPOSE OF REVIEW: This review article presents a summary of the recent magnetic resonance spectroscopic studies of pediatric mood disorders. RECENT FINDINGS: Magnetic resonance imaging is a promising tool for investigating the biologic substrates of neuropsychiatric disorders without the use of ionizing radiation. This novel technique has been recently applied to pediatric patients with mood disorders. Structural, chemical, and functional abnormalities in pediatric patients with mood disorders have been reported. SUMMARY: To date, only modest numbers of pediatric studies using magnetic resonance imaging have been conducted. Most of these studies have small sample sizes and heterogeneous subject groups. These studies have provided important information regarding the underlying neuro-circuitry and pathophysiology of these complex and disabling disorders, however.

Brain↗
PubMed2004

A meta-analysis of functional neuroimaging in obsessive-compulsive disorder.

Recent neurobiological models of obsessive-compulsive disorder (OCD) posit that a dysfunction in orbitofrontal-subcortical circuitry underlies the etiology of this disorder. Much of the empirical support for these theories comes from studies using neuroimaging techniques to compare brain activity in OCD patients with that in non-OCD controls. Qualitative reviews of this literature implicate the orbitofrontal cortex, caudate nuclei, and thalamus. In this study, a meta-analysis was conducted to summarize the results of studies using positron emission tomography (PET) and single photon emission computed tomography (SPECT) to investigate brain activity in OCD. Results suggest that differences in radiotracer uptake between patients with OCD and healthy controls have been found consistently in the orbital gyrus and the head of the caudate nucleus. No other significant differences were found. The implications of these results for theories regarding the etiology of OCD are discussed.

Caudate Nucleus↗
PubMed2004

Acquired cerebral hemiatrophy: idiopathic?

The authors report the case of a young man with acquired cerebral hemiatrophy that was progressive initially but stabilized after a few months. He did not have any seizure throughout the course of his illness. No definite cause was evident despite extensive investigations. He did have a slight increase in white cell count on a cerebrospinal fluid study done during the progressive phase of his illness suggesting that an unidentified infective or inflammatory illness may have resulted in the cerebral hemiatrophy. The authors suggest that Rassmusen's encephalitis may in fact be a spectrum with the typical descriptions representing one end. The importance of multimodality imaging in evaluating patients with cerebral hemiatrophy is discussed.

Adult↗
PubMed2003

Decompressive craniectomy for intractable cerebral edema: experience of a single center.

Several case reports and small clinical series have reported benefits of decompressive hemicraniectomy in patients with intractable cerebral edema and early clinical herniation. Specific indications and timing for this intervention remain unclear. We present our experience with this procedure in a subset of 18 patients with massive cerebral edema refractory to medical management, treated with decompressive craniectomy over a 3-year period (1997 to 2000). Computerized tomography (CT) scans were independently analyzed by a neuroradiologist blinded to clinical outcome. Eleven male and seven female patients, ages 20 to 69 years (mean +/- SEM, 46 +/- 14 years), underwent hemicraniectomy for the following diagnoses: 12 hemispheric infarcts, 3 traumatic intracerebral hemorrhages/contusions, 2 nontraumatic intraparenchymal hemorrhages (ICH), and 1 subdural empyema. This population included four patients with aneurysmal subarachnoid hemorrhage (SAH). Patients were followed for a mean of 10 months. Clinical factors including age, side of lesion, preoperative herniation signs, and early surgery (<12 or <24 hours) were not significantly associated with mortality or Glasgow outcome score (GOS). Preoperative CT evidence of transtentorial herniation (present in 5/17 patients) was associated with mortality ( = 0.04), while preoperative uncal herniation (8/17 patients) was associated with poor outcome (GOS > 1) ( = 0.01). Favorable outcome (GOS > 3) occurred in six patients, three with spontaneous or traumatic focal hematomas. Of four patients with SAH, one died while the others were severely disabled (GOS 3). Seven of nine patients with malignant MCA infarctions unrelated to SAH had poor outcomes. The overall mortality was 4/18 (22%). Patients with refractory cerebral swelling secondary to focal hematomas may have better outcomes following decompressive craniectomy. Patients with preexisting SAH seem to have poor outcomes, possibly related to other neurologic comorbidities. Hemicraniectomy requires definition of proper timing. Preoperative CT findings, especially transtentorial and uncal herniation may be useful in defining when decompressive surgery should not be performed.

Adult↗
PubMed2003

Dipole source analysis of laser-evoked subdural potentials recorded from parasylvian cortex in humans.

The location of the human nociceptive area(s) near the Sylvian fissure is still controversial in spite of evidence from imaging and evoked potential studies that noxious heat stimuli activate somatosensory areas in that region. Some studies have suggested the secondary somatosensory cortex (SII) on the upper bank of the Sylvian fissure posterior to the central sulcus, others the anterior insula or parietal area 7b. In this study, we applied dipole source analysis techniques to laser-evoked potentials (LEPs) that were recorded from subdural grid electrodes in three patients. As a functional marker, auditory-evoked potentials (AEPs) with a generator on the opposite bank of the Sylvian fissure were recorded from the same electrodes. The LEP global field power (GFP), a measure of spatial variance, showed a first peak at about 150 ms latency, corresponding to the latency of the N1 recorded from the scalp. In contrast to scalp recordings, the amplitude of the first GFP peak recorded from the grid was larger than the second peak (P2). This finding suggests that the generator of N1, but not that of later LEP components, was close to the subdural grids. When a regional source was fitted to the first GFP peak, its location was within the frontoparietal operculum in all patients. On average, the LEP source was 13 mm anterior, 6 mm superior, and 2 mm medial of the AEP source. This relative location also suggests a source within the frontoparietal operculum overlying the insula. At the latency of the first GFP peak, source orientation pointed inward, suggesting a generator within the inner vertical surface of the operculum. Somatotopy was assessed in one patient and was consistent with that of the projection area of the presumed nociceptive thalamic nucleus posterior part of the ventromedial nucleus, but differed from that of SII. These findings suggest that the nociceptive area in human parasylvian cortex that is activated most rapidly by noxious heat pulses may be separate from the tactile SII area.

Adult↗
PubMed2002

Advanced magnetic resonance imaging techniques for patients with hemifacial spasm.

PURPOSE: To review the underlying causes, diagnostic issues, and treatment of hemifacial spasm, with emphasis on advanced MRI techniques. METHODS: Brief technical note. RESULTS: High-resolution T1- and T2-weighted spin-echo and/or gradient echo imaging of the posterior fossa should be performed with the use of intravenous gadolinium for maximum contrast between CSF, vessel, and nerve. Magnetic resonance angiography is often useful, and new state-of-the-art sequences provide more detail. CONCLUSIONS: As MRI techniques improve, diagnosis and treatment of patients with hemifacial spasm will become easier. Ophthalmologists should be aware of these new magnetic resonance techniques.

Hemifacial Spasm↗
PubMed2002

Astroblastoma: radiologic-pathologic correlation and distinction from ependymoma.

SUMMARY: Astroblastoma is a rare primary glial tumor with a characteristic appearance on neuroradiologic images. Typically, astroblastomas are large, lobulated, peripheral, supratentorial, solid, and cystic masses with relatively little associated vasogenic edema and tumor infiltration for their large size. The solid component of the mass has a bubbly appearance and a T2 signal that is isointense to gray matter. Punctate calcifications are often present. Neuroradiologists should be familiar with the characteristic appearance of this tumor.

Adolescent↗