A method for the assessment of the functional neuroanatomy of human sleep using FDG PET.

Although sleep is characterized by relative behavioral inactivity, cortical activity is known to cycle in well-defined periods across this state. Cognitive function during sleep has been difficult to define, although disturbances in sleep are known to result from, and to cause, various human pathologies, including neuropsychiatric disorders. Assessment of brain function in humans (related to cognitive operations) during sleep has been limited, until recently, to surface electrophysiologic recordings that limit analysis of regional function, particularly in deep structures.

Serotonin in aging, late-life depression, and Alzheimer's disease: the emerging role of functional imaging.

Serotonin (5-HT) neuron and neurotransmitter loss in normal aging and neuropsychiatric diseases of late life may contribute to behavioral changes commonly observed in the elderly population. Extensive evidence implicates a deficit in serotonergic neurotransmission in the development of major depression. It has been further suggested that the age-related changes in 5-HT neurons may predispose the elderly to develop depression.

Cerebral MR imaging in intravascular lymphomatosis.

MR imaging data were reviewed retrospectively in four male patients (32 to 74 years old) with histologically confirmed intravascular lymphomatosis (IVL), a rare, aggressive form of non-Hodgkin lymphoma. MR findings included infarct-like lesions (n = 2), focal parenchymal enhancement (n = 3), dural/arachnoid enhancement (n = 2), and, in one case, nonspecific, patchy foci of increased signal in the white matter on long-TR images. All patients had multifocal lesions.

AIDS-related MR hyperintensity of the basal ganglia.

Purpose: Our goal was to describe the MR imaging appearance and clinical pathologic correlates of bilateral basal ganglia hyperintensity in acquired immunodeficiency syndrome (AIDS).

Methods: Medical records and laboratory data were reviewed retrospectively in nine cases of bilateral basal ganglia hyperintensity on long-repetition-time MR images. Opportunistic infections of the central nervous system were excluded by clinical and laboratory data.

Role of positron emission tomography in staging esophageal cancer.

Background: Conventional noninvasive staging of esophageal cancer is inaccurate. This study investigated the role of positron emission tomography (PET) in staging esophageal cancer.

Methods: Patients with potentially resectable esophageal cancer were included.

Mirror-image optic nerve dysplasia with associated anisometropia in identical twins.

Background: Monozygotic (MZ) or "identical" twins arise from a single fertilized egg, which divides into two embryos at an early stage of development. As a result, MZ twins have identical genomes and are always of the same sex.

Methods: A case of optic nerve hypoplasia and anisometropia, in association with mirror-image presentation in a set of 12-year-old identical twins, is reported.

Contemporaneous bilateral pallidotomy.

To investigate the effects of bilateral posteroventral pallidotomy (PVP) for Parkinson's disease (PD), the authors reviewed the technique and neurological outcome in a number of patients who had undergone bilateral pallidotomy. The authors have previously reported the outcome of PVP in 25 bilateral and 25 unilateral surgeries, rating the patient's postural stability, speech, and total Unified Parkinson's Disease Rating Scale scores. A second, separate group of 23 patients who underwent contemporaneous bilateral PVP were evaluated for early onset idiopathic PD, levodopa failure syndrome, and severe bilateral dyskinesia as well as akinetic "off" states.

Quantification of neuroreceptors in the living human brain: IV. Effect of aging and elevations of D2-like receptors in schizophrenia and bipolar illness.

In a previous study of 10 drug-naive schizophrenic patients, the density of D2 dopamine receptors was found to be elevated in the caudate nucleus. The study raised questions about the influence of the age of the patients, the relationship of receptor density to psychosis, and the accuracy of the method used to obtain this evidence. Using positron emission tomography and constrained analysis of the brain uptake of the radioligand N-[11C]methyl-spiperone ([11C]NMSP), we tested four questions: Were the assumptions underlying the quantitation valid? Is there an age decline of the density of D2-like dopamine receptors in drug-naive schizophrenia and bipolar illness? If so, is it different from that observed in normal aging? Are D2-like dopamine receptors elevated at any age in either drug-naive schizophrenic or psychotic bipolar illness patients? NMSP and haloperidol partition volumes and plasma protein fractions were not significantly different among patient groups and normal volunteers.

Quantification of neuroreceptors in the living human brain: III. D2-like dopamine receptors: theory, validation, and changes during normal aging.

Dopamine receptor density is believed to decline in normal aging. To test this hypothesis, we measured the density of dopamine D2-like receptors in vivo in the neostriatum of normal living humans by using the graphical method. This method determines the D2-like dopamine receptor density in the human brain with an occupying ligand (unlabeled haloperidol) and a radioligand (labeled 3-N-methylspiperone).

MR imaging of the meninges. Part I. Normal anatomic features and nonneoplastic disease.

The structural organization of the dura and leptomeninges is reflected in its magnetic resonance (MR) imaging appearance in normal and disease states. Two distinct enhancement patterns are characterized: dura-arachnoid enhancement and pia-subarachnoid space enhancement. The dura-arachnoid pattern consists of curvilinear enhancement overlying the brain and immediately deep to the inner table of the calvaria, as well as along the falx and tentorium.

Regional hypometabolism in Alzheimer's disease as measured by positron emission tomography after correction for effects of partial volume averaging.

Measurements of cerebral metabolism in patients with Alzheimer's disease (AD) using PET are artifactually depressed due to partial volume averaging of brain tissue activity with enlarged CSF spaces. To investigate the effects of correction for the expansion of CSF spaces on regional metabolic measures, as well as the correlations between neuropsychological test results and resting cerebral metabolism before and after partial volume correction, we applied an MRI-based method of partial volume correction to 18F-fluorodeoxyglucose (FDG)-PET data from eight patients diagnosed with probable AD and ten healthy elderly individuals. Before correction, the AD group had significantly lower cortex-to-cerebellum ratios in the posterior temporal, parietal, and frontal lobes in comparison to the control subjects.

MR-based correction of brain PET measurements for heterogeneous gray matter radioactivity distribution.

Partial volume and mixed tissue sampling errors can cause significant inaccuracy in quantitative positron emission tomographic (PET) measurements. We previously described a method of correcting PET data for the effects of partial volume averaging on gray matter (GM) quantitation; however, this method may incompletely correct GM structures when local tissue concentrations are highly heterogeneous. We have extended this three-compartment algorithm to include a fourth compartment: a GM volume of interest (VOI) that can be delineated on magnetic resonance (MR) imaging.

Influence of spatially heterogeneous background activity on "hot object" quantitation in brain emission computed tomography.

Purpose: Our goal was to evaluate the influence of spatially heterogeneous background activity on "hot object" quantitation in brain emission CT.

Method: We studied the effects of spatially heterogeneous background activity on hot object quantitative recovery in simulations of both spheres and realistic brain distributions (utilizing human MRI data).

Results: Significant underestimation of object activity concentration was seen for both cortical and subcortical hot objects, with increasing underestimation for increasing hot object/surrounding gray matter contrast.

The striated cerebellum: an MR imaging sign in Lhermitte-Duclos disease (dysplastic gangliocytoma).

Purpose: To correlate the magnetic resonance (MR) imaging features of and histologic findings in Lhermitte-Duclos disease (LDD) (dysplastic gangliocytoma).

Materials And Methods: MR imaging and histologic data from eight patients with the diagnosis of LDD were retrospectively reviewed. Gross pathologic specimens were also available in one case.

Tumoral calcinosis causing bone erosion in a renal dialysis patient.

Tumoral calcinosis is a rare disorder manifest by large calcific periarticular masses. Associated bone destruction has been described previously only once. The radiographic and computed tomographic (CT) findings of bone erosion in a case of tumoral calcinosis in a renal dialysis patient are presented.

Computed tomography appearance of bone metastases of leiomyosarcoma.

Bone lesions in leiomyosarcoma are uncommon. When encountered, they are usually a late manifestation of disease seen in the setting of widespread systemic metastases. We present five cases of metastatic leiomyosarcoma, including one in which a bone lesion predated detection of a primary gastric leiomyosarcoma and one in which bone metastases signaled disease recurrence.

Quantification of mu and non-mu opiate receptors in temporal lobe epilepsy using positron emission tomography.

Alterations in a variety of neurotransmitter systems have been identified in experimental models of epilepsy and in brain tissue from patients with intractable temporal lobe seizures. The availability of new high-affinity radioligands permits the study of some neuroreceptors in vivo with positron emission tomography (PET). We previously characterized the in vivo binding of 11C-carfentanil, a potent and selective mu opiate receptor agonist, and described increases in 11C-carfentanil binding in the temporal neocortex of patients with unilateral temporal lobe epilepsy.

Case report 698: Osteoma of the clavicle.

We have presented a case of an osteoma of the clavicle in a 41-year-old man. The possibility of alternate diagnoses--in particular, ancient osteochondroma, posttraumatic hyperostosis, and parosteal osteosarcoma--was addressed. However, the pathological examination was most consistent with the diagnosis of osteoma.

Correction of PET data for partial volume effects in human cerebral cortex by MR imaging.

Due to the limited spatial resolution of positron emission tomography (PET), the accuracy of quantitative measurements of regional metabolism or neuroreceptor concentration is influenced by partial volume averaging of brain with CSF, bone, and scalp. This effect is increased in the presence of cortical atrophy, as in patients with Alzheimer disease (AD). Correction for this underestimation in PET measurements is necessary for the comparison of AD patients and normal controls.

Anatomical localization for PET using MR imaging.

Accurate localization of an imaging plane of interest is often needed prior to a positron emission tomographic (PET) study. We have developed a simple method for accurate and reproducible selection of an imaging plane for PET using magnetic resonance (MR) imaging. This method is useful when optimal sampling of specific brain structures, such as small subcortical nuclei, or when a specific imaging angle is required for the PET study.

Laser surgery for vocal cord carcinoma involving the anterior commissure.

Endoscopic laser surgery is an established means of treatment for benign laryngeal lesions. Laser surgery for early (stages I and II) squamous cell carcinoma is still being tested. Treatment of glottic tumors extending to the anterior commissure is in itself controversial.