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Biomedical subjects

M R Day

Publications and source records attributed to M R Day.

14 recordsLinked to original sources
PubMed1999

High spatial resolution 1H-MRSI and segmented MRI of cortical gray matter and subcortical white matter in three regions of the human brain.

High-resolution MR imaging and spectroscopic imaging were used to study differences in proton spectra between cortical gray matter and subcortical white matter in 23 normal volunteers using a 1.5 T scanner and surface coil receivers. A point-resolved spectroscopy (PRESS) volume with an 8 x 8 x 8 phase-encoding matrix was used to acquire over 1900 0.09-0.2 cc spectral voxels. The high-resolution (0.7 x 0.7 x 0.8 mm3 or 0.8 x 0.8 x 1 mm3) images were corrected for the surface coil reception profile and segmented into cerebrospinal fluid (CSF) and gray and white matter to correlate with the spectra. The data showed that N-acetyl aspartate (NAA) and creatine (Cr) were higher in the gray matter than in the white matter (NAA(g/w) = 1.4+/-0.36, Cr(g/w) = 1.4+/-0.41). Choline was significantly lower in the gray matter of the occipital lobe than in the white matter (0.73+/-0.19), but not significantly different in the other regions. NAA/Cho was found to be significantly higher in the occipital lobe than in the left frontal or vertex regions.

Adult↗
PubMed1998

The use and abuse of wound care materials in the treatment of diabetic ulcerations.

With the ever-increasing availability of wound care materials for use in diabetic foot ulcerations, a thorough understanding of the indications and applications of these materials is important for wound-management success. The coupling of a lack of understanding of the interaction of wound care materials and the dynamic nature of wound-healing physiology may lead to a protracted healing course that may constitute an abuse of an otherwise useful adjunct to wound healing protocols. This article provides an overview of wound care products, their indications, and possible complications of inappropriate use.

Administration, Topical↗
PubMed1997

Serial proton magnetic resonance spectroscopy imaging of glioblastoma multiforme after brachytherapy.

The utility of three-dimensional (3-D) proton magnetic resonance spectroscopy (1H-MRS) imaging for detecting metabolic changes after brain tumor therapy was assessed in a serial study of 58 total examinations of 12 patients with glioblastoma multiforme (GBM) who received brachytherapy. Individual proton spectra from the 3-D array of spectra encompassing the lesion showed dramatic differences in spectral patterns indicative of radiation necrosis, recurrent or residual tumor, or normal brain. The 1H-MRS imaging data demonstrated significant differences between suspected residual or recurrent tumor and contrast-enhancing radiation-induced necrosis. Regions of abnormally high choline (Cho) levels, consistent with viable tumor, were detected beyond the regions of contrast enhancement for all 12 gliomas. Changes in the serial 1H-MRS imaging data were observed, reflecting an altered metabolism following treatment. These changes included the significant reduction in Cho levels after therapy, indicating the transformation of tumor to necrotic tissue. For patients who demonstrated subsequent clinical progression, an increase in Cho levels was observed in regions that previously appeared either normal or necrotic. Several patients showed regional variations in response to brachytherapy as evaluated by 1H-MRS imaging. This study demonstrates the potential of noninvasive 3-D 1H-MRS imaging to discriminate between the formation of contrast-enhancing radiation necrosis and residual or recurrent tumor following brachytherapy. This modality may also allow better definition of tumor extent prior to brachytherapy by detecting the presence of abnormnal metabolite levels in nonenhancing regions of solid tumor.

Aspartic Acid↗
PubMed1997

Factors associated with pedal ulceration in patients with diabetes mellitus.

Understanding the factors associated with pedal ulceration in patients with diabetes mellitus will increase the successful management of the high-risk diabetic foot and decrease the occurrence of ulcerative events. The authors review the associative factors that have been shown to be involved with pedal ulceration.

Aged↗
PubMed1996

Cellulitis secondary to web space dermatophytosis.

Cellulitis occurring in the lower extremity is encountered frequently and results from a breach of the skin and inoculation of opportunistic bacteria. It has been shown that when web space dermatophytosis is present, changes may occur in normal skin morphology and bacterial flora that can result in severe infection. Knowledge of the pathophysiology of interdigital dermatophytosis allows the clinician to choose the most appropriate empiric antibiotic therapy when treating a secondarily caused cellulitis of the lower extremity.

Aged↗
PubMed1995

Proton spectroscopic imaging of the human brain using phased array detectors.

Two and four-coil phased array detectors have been developed to increase the sensitivity of proton spectroscopic imaging of the human brain. These include a quadrature figure-8 coil for the study of the vertex, several arrays of 2-4 small overlapping (6-8 cm diameter) circular coils and a combination figure-8 coil plus circular coil. These were constructed in our laboratory and tested to assess their utility for brain spectroscopy. Methods for optimally combining the data from the independent receivers based on the analytical coil maps or measured signal to noise ratios (SNRs) of the data were investigated. High spatial resolution (0.2-0.4 cm3 voxel size) two- or three-dimensional chemical shift images of normal brain were obtained in 17-minute acquisitions. These spatial resolutions are comparable to those previously obtained with conventional small surface coils, but the specialized detectors allow this sensitivity to be achieved for a larger region or for previously inaccessible areas such as the top of the head. The coverage and SNR increases demonstrated are similar to those obtained in magnetic resonance phased array imaging.

Brain↗
PubMedDate not supplied

Volume MRI and MRSI techniques for the quantitation of treatment response in brain tumors: presentation of a detailed case study.

Patients with primary brain tumors may be considered for several different treatments during the course of their disease. Assessments of disease progression and response to therapy are typically performed by visual interpretation of serial MRI examinations. Although such examinations provide useful morphologic information, they are unable to reliably distinguish active tumor from radiation necrosis. This poses a particular problem in the assessment of response to localized radiation therapies such as gamma knife radiosurgery. In this paper, we present methodology for evaluating changes in tissue morphology and metabolism based on serial volumetric MRI and magnetic resonance spectroscopic imaging (MRSI) examinations. Registration and quantitative analysis of these data provide measurements of the temporal and spatial distributions of gadolinium enhancement and of N-acetylasparate, choline, creatine, and lactate/lipid. The key features of this approach and the potential clinical benefits are illustrated by a detailed analysis of six serial MRI/MRSI examinations and three serial 1-[F-18] fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) studies on a patient with a recurrent anaplastic astrocytoma.

Adult↗
PubMedDate not supplied

Delta phalanx.

The authors present a case of congenital, bilateral, symmetrical, and purely transverse plane, abductus deformity of the second digit. The deformity appears to be familial in nature, although other possible etiologies remain including premature closure of the distal-lateral epiphysis of the middle phalanx, or a C-shaped epiphysis of the middle phalanx. The authors review a similar deformity described in orthopedic literature known as a delta phalanx.

Adult↗
PubMedDate not supplied

The "Z" osteotomy versus the Kalish osteotomy for the correction of hallux abducto valgus deformities: a retrospective analysis.

A retrospective analysis of hallux abducto valgus surgery performed between 1990 and 1995 where the "Z" osteotomy and Kalish osteotomy were utilized was performed. Objective and subjective data were collected to determine the effectiveness of the Z osteotomy versus the Kalish osteotomy. Twenty cases of hallux abducto valgus where the Z osteotomy was utilized were evaluated on the basis of intermetatarsal angle correction and alleviation of preoperative symptoms. The same evaluation was performed on 21 cases where the Kalish osteotomy was utilized. There did not appear to be an appreciable difference in intermetatarsal angle correction between the two osteotomies; however, the Kalish osteotomy did alleviate preoperative symptoms to a greater degree compared with the Z osteotomy.

Adolescent↗
PubMedDate not supplied

Factors associated with methicillin resistance in diabetic foot infections.

Methicillin-resistant staphylococcal infections often present a challenge to physicians treating patients with pedal wounds. Most methicillin-resistant Staphylococcus aureus infections have been thought of as nosocomial in origin. Several studies have identified specific modes of transmission via hospital reservoirs such as the anterior nares of the patient, inanimate objects within close proximity of the patient, and direct contamination from health care providers. Exposure of patients to these reservoirs through hospitalization has been shown to increase the patient's risk of obtaining a methicillin-resistant S. aureus infection. Diabetic patients with a high risk for foot complications may be in greater danger of developing a methicillin-resistant S. aureus infection in that repeated hospitalizations, lengthier hospital stays, and the presence of open wounds facilitate exposure to these reservoirs.

Cross Infection↗
PubMedDate not supplied

Alignment of volume MR images and high resolution [18F]fluorodeoxyglucose PET images for the evaluation of patients with brain tumors.

PURPOSE: The goal of the study was to investigate the use of automated registration techniques for interpretation of volume MR and high resolution FDG-PET images that were obtained from patients with brain tumors. METHOD: Twenty-one patients with brain tumors were studied on one or more occasions using MRI and high resolution FDG-PET. The data were aligned using automated volume- and surface-matching algorithms. Composite images comprising the resliced pre- and postgadolinium spoiled GRE, T2-weighted SE, and PET data were constructed to correlate intensities of regions on the PET images with regions that corresponded to normal gray matter, white matter, and gadolinium enhancement. RESULTS: The accuracy of registration between the MR and PET images was estimated to be within 1-2 mm based upon the distance between surfaces of the outside of the head. In 12 of the 24 examinations, there were diagnoses of recurrent tumor, with only 5 of these exhibiting regions of higher FDG uptake than normal gray matter. For 19 of the 24 studies, the anatomic context provided by the registered MR images was found to be important in distinguishing recurrent tumor from necrosis based upon FDG uptake. CONCLUSION: The automated alignment was found to be an important factor in interpreting the high resolution PET images. This was particularly true for small lesions close to the cortex and for situations where FDG uptake had been reduced by prior treatment with radiation therapy.

Adult↗