Phase-sensitive cardiac tagging--REALTAG.

Fully inverting spins, instead of merely saturating them, provides superior contrast for tagging procedures. The resulting improvement in tag contrast-to-noise ratio (CNR) yields higher-precision tag detection. Also, thinner slices and hence reduced tag separations can be employed, providing displacement and strain measurements with better spatial resolution. Alternatively, the improved tag contrast can be used to obtain cine images covering a greater portion of the cardiac cycle. The use of standard magnitude reconstruction for images of these inversion tags causes rectification of the negative-valued signals from the tags, confounding the image interpretation. Therefore, a phase-sensitive reconstruction scheme of the inverted tags must be employed. Here we demonstrate the implementation of inverted tags with phase-sensitive reconstruction in a ramped-flip-angle, steady-state free precession (SSFP) sequence.     

The impact of near-patient testing on the organisation and costs of an anticonvulsant clinic

A near-patient testing facility was provided at an anticonvulsant clinic and compared with the previously offered service. Productivity was increased by over 20%, with savings in medical and nursing staff time. This saving in time is offset by increased consumable costs but still enables a significant net saving.     

Preliminary investigation of respiratory self-gating for free-breathing segmented cine MRI.

Segmented cine MRI generally requires breath-holding, which can be problematic for many patients. Navigator echo techniques, particularly successful for free-breathing coronary MRA, are incompatible with the acquisition strategies and SSFP pulse sequences commonly used for cine MRI. The purpose of this work is to introduce a new self-gating technique deriving respiratory gating information directly from the raw imaging data acquired for segmented cine MRI. The respiratory self-gating technique uses interleaved radial k-space sampling to provide low-resolution images in real time during the free-breathing acquisition that are compared to target expiration images. Only the raw data-producing images with high correlation to the target images are included in the final high-resolution reconstruction. The self-gating technique produced cine series with no significant differences in quantitative image sharpness to series produced using comparable breath-held techniques. Because of the difficulties associated with breath-holding, the respiratory self-gating technique represents an important practical advance for cardiac MRI. , Inc.     

Comparison of scleral and corneal Tono-Pen readings.

PURPOSE: To compare scleral Tono-Pen (Medtronic Solan, Jacksonville, FL) readings to corneal Tono-Pen readings. METHODS: Intraocular pressure (IOP) was measured prospectively in 72 eyes of 37 adult patients and in 10 eyes of 5 children. Measurements were taken on the central cornea and on the sclera. Recorded measurements were within 5% confidence levels by Tono-Pen. RESULTS: Corneal IOP ranged from 10 to 28 mm Hg (mean +/- standard deviation, 17.0 +/- 3.8 mm Hg). Scleral measurements ranged from 4 to 99 mm Hg (40.4 +/- 23.0 mm Hg). Scleral measurements ranged from 11 mm Hg lower to 76 mm Hg higher than corneal measurements. CONCLUSIONS: Tono-Pen readings obtained from sclera are of no clinical value and should not be used to approximate corneal IOP.     

High-Dose Naltrexone and Liver Function Safety

Studies have found naltrexone useful in the treatment of diseases other than opiate addiction in which endogenous opioids presumably play a role, such as alcoholism and eating disorders. Some of these studies involve high doses (100–200 mg bid). Because investigational studies with high doses (300 mg/day) reported clinically significant increases in liver enzyme levels, the authors measured a spectrum of liver function parameters in response to high doses of naltrexone in a double-blind, crossover trial (100 mg bid) followed by an open-label period (200 mg bid). They observed no adverse clinical or laboratory changes in liver function in association with high-dose naltrexone therapy in eating disorders.     

Cystic renal melanoma: CT/ultrasound correlation

A new computed tomographic and sonographic appearance of renal metastatic melanoma is described. Bilateral cystic masses with thick walls, many with mural nodules, were noted. Sonography also demonstrated complex echopenic masses with irregularly thickened walls and mural nodules.     

Computer-Assisted Detection of Pulmonary Nodules: Preliminary Observations Using a Prototype System with Multidetector-Row CT Data Sets

The continued revolution in multidetector-row CT (MDCT) scanning increases the quality of lung imaging but at the cost of a greater burden of data for review and interpretation. This article discusses our preliminary experience with prototype software for lung nodule detection and characterization using MDCT data sets. We discuss the potential role of computer-assisted detection (CAD) as applied to the automatic detection of lung nodules. We also review the process of CAD, outline its potential results, and explore how it may fit into existing radiology practice. Finally, we discuss MDCT data-acquisition parameters and how they may affect the performance of CAD.     

Animal models in the investigation of anorexia

Anorexia nervosa (AN) is an eating disorder of unknown origin that most commonly occurs in women and usually has its onset in adolescence. Patients with AN invariably have a disturbed body image and an intense fear of weight gain. There is currently no definitive treatment for this disease, which carries a 20% mortality over 20 years. Development of an appropriate animal model of AN has been difficult, as the etiology of this eating disorder likely involves a complex interaction between genetic, environmental, social, and cultural factors. In this review, we focus on several possible rodent models of AN. In our laboratory, we have developed and studied three different mouse models of AN based on clinical profiles of the disease; separation stress, activity, and diet restriction (DR). In addition, we discuss the spontaneous mouse mutation anx/anx and several mouse gene knockout models, which have resulted in an anorexic phenotype. We highlight what has been learned from each of these models and possibilities for future models. It is hoped that a combination of the study of such models, together with genetic and clinical studies in patients, will lead to more rational and successful prevention/treatment of this tragic, and often fatal, disease.     

Amyloid peptide enhances nail rusting: novel insight into mechanisms of aging and Alzheimer's disease

Oxidative stress is believed to play a major role in the dysfunction and degeneration of neurons that occurs in Alzheimer's disease (AD). Amyloid beta-peptide forms insoluble aggregates in the brains of AD patients and it has been shown that the neurotoxic actions of amyloid beta-peptide involve membrane lipid peroxidation. However, it is not known how amyloid beta-peptide induces oxidative stress. Here we describe a simple experiment that we performed 6 years ago that demonstrates that amyloid beta-peptide is itself a source of oxyradicals. The weights of iron nails were recorded and the nails were then incubated in one of three different solutions: water (control), 1mM amyloid beta-peptide (1-40) in water, and 1mM bovine serum albumin in water. After 1 month of incubation the nails were then removed, allowed to dry, and then their weights determined. The weights of all the nails decreased, but the amount of weight decrease in the nails that had been incubated in the presence of amyloid beta-peptide was approximately twice that of the nails incubated in the control solutions. These data provide direct evidence that amyloid beta-peptide generates, or facilitates the production of, oxyradicals thereby enhancing metal oxidation.     

Structural change in dopamine D2 receptor gene in a patient with neuroleptic malignant syndrome

Dysfunction of the dopaminergic system has been suggested as a pathogenic mechanism in neuroleptic malignant syndrome. Therefore, we examined the complete coding sequences of the dopamine D₂ receptor (DRD₂) gene for structural abnormalities in 12 patients with a history of NMS, including two cases of familial NMS. Mutational analysis was performed by denaturing gradient gel electrophoresis (DGGE), a highly sensitive technique for detecting sequence differences. We found in one patient with a history of NMS a nucleotide substitution at codon 310 (CCG→TCG) of exon 7 of the DRD₂ gene which predicts the replacement of proline to serine in the third cytoplasmic loop of the receptor, a part of the receptor that interacts with G-proteins. A larger series of patients with NMS needs to be investigated to establish whether this allele is associated with an increased susceptibility to NMS. © 1995 Wiley-Liss, Inc.