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Biomedical subjects

D M Kaufman

Publications and source records attributed to D M Kaufman.

At least 55 records · Page 3Linked to original sources
PubMed1992

The persistent vegetative state: an analysis of clinical correlates and costs.

A review was compiled of 23 patients in the persistent vegetative state; a condition that developed while the patients were in an acute care hospital. Before the onset of the persistent vegetative state, eight patients had had dementia, 11 were functionally dependent, and seven had neurologic disorders that gradually led to the persistent vegetative state. For patients in the persistent vegetative state, three types of mechanical support--respirators, nasogastric or gastrotomy tubes, and intravenous lines--were utilized. All three were necessary in 43% of patients, two types in 52%, and one type in 4%. All patients in the persistent vegetative state required at least one type of mechanical assistance. Their course was complicated in all cases by incontinence, and in the majority, by decubiti, pneumonia, and urinary tract infection. Only one patient improved enough to be able to say a few words. These patients required active medical care and invasive procedures that were costly but futile. The hospital bills obtained for 13 patients averaged $170,000, and the length of stay for all patients averaged 197 days, the equivalent to a total number of bed-days of 12.5 bed-years. The poor outcomes, requirements for mechanical support, and frequency of complications--especially when neurologic impairments were present before the onset of the persistent vegetative state--should be considered when evaluating the cost in hospital bills and bed occupancy.

Adult↗
PubMed1989

Experimental trials with Gd(DO3A)--a nonionic magnetic resonance contrast agent.

Gd(DO3A), a member of a new family of nonionic MRI contrast agents, was evaluated in vivo in a rat model. In 10 animals, enhancement of an intracerebral glioma was studied following Gd(DO3A) injection. Correlation with tissue pathology was obtained in all cases. Comparative studies of renal enhancement were performed in 15 animals, utilizing disodium Gd(DTPA)2-, sodium-Gd(DOTA)-, and Gd(DO3A). With the glioma model, Gd(DO3A) administration provided enhancement of tissue with an altered blood brain barrier, thus permitting identification of the bulk of the neoplastic lesion. Comparative studies revealed that enhancement of normal renal medulla was equal or superior with Gd(DO3A).

Animals↗
PubMed1989

Facial dyskinesias.

The face is prominently or exclusively involved in several involuntary movement disorders, called "facial dyskinesias," in addition to the common buccolingual form of tardive dyskinesia. This review describes the appearance of the most frequently occurring facial dyskinesias: chorea, dystonia, tremor, and tics. Some new treatments are discussed.

Diagnosis, Differential↗
PubMed1989

Anatomy of the proximal femur as seen with three-dimensional magnetic resonance imaging.

Magnetic resonance imaging (MRI) is being applied successfully to the study of the musculoskeletal system with notable recent advances, including the use of three-dimensional imaging techniques. The authors introduce three-dimensional MRI as a technique for examining proximal femoral anatomy and suggest its use as an improvement on current methods for prosthetic hip design. The proximal femurs of 14 cadavers were scanned using a three-dimensional FISP technique and the images were subsequently manipulated on a three-dimensional MRI image-processing workstation to produce rotated surface reconstructions and multiplanar reformatted images. The surface rotations showed that the marrow cavity contours closely follow the contours of the external cortex. Axially reformatted images allowed relative area measurements of the marrow cavity, quantifying the variability between subjects.

Aged↗
PubMed1988

The straight and narrow path to good head and spine MRI.

The path to good head and spine images is narrow and treacherous. We have attempted to give the traveller a small but important set of basic rules, enabling him to cross with success. 1. Averaging can be used to achieve sufficient SNR for thin sections, but the cost in terms of scan time is high. Zooming the image (reducing the field of view) should generally be avoided, as the price in terms of SNR is very high. 2. Rectangular pixels and half-Fourier imaging are two methods for decreasing scan time. HFI, which produces high spatial resolution images, can be used when the SNR is not a limiting factor. Rectangular pixels improve the SNR, but decrease resolution. 3. To achieve good T1 contrast with spin echo imaging, set TE less than or equal to 20 msec. and TR less than or equal to 600 msec. For T2 weighted images, a TR between 2.0 and 3.0 sec. is preferred, typically with two echoes: for example, TEs of 25 and 90 msec. 4. Better slice profiles or gaps between slices can be used to combat slice-to-slice interference. This results in improved SNR on T1 weighted images and improved contrast on T2 weighted images. 5. Low bandwidth techniques may be used to improve the SNR on both T1 and T2 weighted images. Chemical shift artifact puts a finite limit on the extent to which this can be applied. 6. Motion compensating gradients are a tremendous boon to MRI and should be utilized in all possible head and spine applications. These reduce image degradation from CSF and vessel pulsation, as well as from involuntary motion. 7. Fast imaging techniques can be used in 2-D multislice mode to decrease scan time. Unfortunately the T2 contrast with this approach is far inferior to that of spin echo technique. 3-D FLASH, with 1 mm. sections, T1 contrast superior to spin echo technique, and the potential for high resolution reformatted images, may replace conventional 2-D, T1 weighted, spin echo imaging. Pulse techniques that combine all the advantages mentioned lie in the future. For example, one possible approach is a T2 weighted head screen that incorporates low bandwidth technique and HFI. This would produce high resolution images with reasonable SNR in approximately half the present scan time. Despite any further new developments, the trade-off between image quality and scan time will likely always remain.(ABSTRACT TRUNCATED AT 400 WORDS)

Head↗
PubMed1988

FLASH: clinical three-dimensional magnetic resonance imaging.

Using 3-D FLASH, high resolution, very thin section T1 weighted images of the CNS, spine, and extremities can be obtained. From these single data sets, reformatted images whose resolution is equal to that of the original data set can be constructed in any desired plane. This approach may lead to the replacement of conventional T1 weighted spin echo imaging by 3-D FLASH techniques.

Brain↗
PubMed1988

MR imaging section profile optimization: improved contrast and detection of lesions.

A computer-optimized radio-frequency (RF) pulse for sharper section definition was implemented for T2-weighted magnetic resonance (MR) imaging of the head. Twenty-four patients underwent MR imaging with this technique and also with a conventional spin-echo technique with a sinc pulse filtered with a Hamming window. The contrast between gray and white matter improved 20%-40%, depending on the echo time. In ten patients with multiple sclerosis, use of the computer-optimized RF pulse resulted in detection of 37% more lesions, and power deposition was reduced by 36%. The computer-optimized RF pulse improved image contrast and lesion detection.

Brain↗
PubMed1988

Magnetic resonance imaging with gadolinium-DTPA for detecting cardiac transplant rejection in rats.

To date, no noninvasive tool has gained widespread acceptance as an adequate substitute for endomyocardial biopsy for the diagnosis and grading of cardiac transplant rejection. We examined the potential role of magnetic resonance imaging with gadolinium (Gd)-diethylenetriamine penta-acetic acid (DTPA) image enhancement for the diagnosis of cardiac graft rejection. We studied 15 rats with heterotopic cardiac transplants, nine of which received no immunosuppression, and six of which received cyclosporine, azathioprine, and methylprednisolone. The animals underwent magnetic resonance imaging, which was immediately followed by sacrifice (2-12 days after transplant). Myocardial image enhancement was assessed on T1-weighted images performed before and after administration of Gd-DTPA, 0.5 mmol/kg. Histological specimens were graded I, II, or III to indicate increasing severity of rejection. In the absence of rejection, Gd-DTPA induced mild homogeneous myocardial enhancement. Ten of 11 cases with Grade II or III rejection manifested one or more areas of intense myocardial enhancement. The extent and distribution of intense myocardial enhancement corresponded to the severity and distribution of histological rejection. Quantitative myocardial enhancement, expressed as the ratio of maximal signal intensity after Gd-DTPA to signal intensity before Gd-DTPA administration, separated Grade I animals (1.61 +/- 0.27; mean +/- SD) from Grades II (2.89 +/- 0.58) and III (3.10 +/- 0.77; p less than 0.01) animals. In conclusion, cardiac transplant rejection is characterized by intense T1-weighted image enhancement after administration of Gd-DTPA. Magnetic resonance imaging with Gd-DTPA thus has potential application in the clinical diagnosis of cardiac transplant rejection.

Animals↗
PubMed1987

The efficacy of tilted axial MRI of the CNS.

The angle between the straight axial plane and the orbito-meatal line was measured in 156 consecutive magnetic resonance examinations. Inconsistent head positioning caused this angle to vary by as much as 44 degrees. Careful positioning of the patient by the technologist can minimize this variability, leading potentially to improved image interpretation. To assess the merit of a standardized orientation for MR examinations of the head, straight axial and tilted axial MR scans were compared in 34 patients. The tilted images were obtained parallel to the orbitomeatal line and were found to be superior for visualization of the cerebellum. When correlative x-ray CTs are available or when an abnormality in the posterior fossa is suspected, tilted axial MR scans should be employed.

Brain Diseases↗
PubMed1985

Familial amyotrophic chorea with acanthocytosis. New clinical and laboratory investigations.

A 46-year-old man, the son of normal nonconsanguinous parents, had a rare progressive neurological illness that began in midlife and was characterized by seizures, buccolingual dyskinesia, orofacial tics, choreiform movements, areflexia, and neurogenic muscle atrophy. Acanthocytosis was present. The serum creatine kinase level was elevated and normobetalipoproteinemia was noted. A brother had a similar disorder. These clinical and laboratory characteristics are consistent with those of previously reported cases of neuroacanthocytosis, ie, familial amyotrophic chorea with acanthocytosis (FACWA). Features not previously reported in cases of FACWA and noted in our index patient are as follows: an increased level of free sialic acid was detected in the serum; haloperidol administered in high doses decreased the orofacial tics; absence of the McLeod blood group phenotype was noted; and Hispanic-Puerto Rican ancestry was documented.

Acanthocytes↗
PubMed1983

Usefulness of videotape instruction in an academic department of neurology.

A group of medical students was shown a series of instructional videotapes while taking a required neurology clerkship. Overall, this study group was more accurate (p less than 0.01) in diagnosing illustrated conditions than a control group that did not see the videotapes. Videotape instruction produced better performance in identification in only certain areas: neuropsychologic phenomena, disorders with subtle or unique movements, and seizures. The choice and cost of equipment and some professional assurances are discussed. Costs and professional expectations, as well as the limited usefulness of videotapes, must be acknowledged by clinical departments before embarking on videotape instruction.

Clinical Clerkship↗
PubMed1983

Sinusitis: induced subdural empyema.

In 17 cases of sinusitis-induced subdural empyema, all but 5 occurred in boys or men aged 13 to 33 years. Clinical features were headaches and fever (14 patients), nuchal rigidity (10), and seizures (8). Seven patients had periorbital cellulitis, and 15 had radiographic clouding of at least one sinus. Only five patients had a history of sinusitis. CT identified the empyema accurately in seven patients but failed in two patients who developed subdural empyema while being treated for sinusitis-induced cerebritis. Ten patients had specific bacteriologic etiologies determined by culture of empyema, blood, or sinuses.

Adolescent↗