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Biomedical subjects

D Norman

Publications and source records attributed to D Norman.

At least 271 records · Page 15Linked to original sources
PubMed1976

Computed tomography in the evaluation of malignant glioma before and after therapy.

Sixty-three patients with malignant glioma undergoing chemotherapy and radiotherapy were evaluated with electroencephalography, 99mTc-DTPA imaging, and computed tomography (CT). Tumor size, central lucency, contrast enhancement, surrounding edema, and ventricular size were assessed. CT findings were found to be reliable and often predicted the clinical course. Tumor size, central lucency, and contrast enhancement increased in patients with clinical deterioration and decreased in those with improvement. The CT scan also provided additional information of value in adjunctive therapy, such as the presence of cysts or ventricular obstruction. In general, CT gave a more complete profile of tumor characteristics than other diagnostic modalities.

Antineoplastic Agents↗
PubMed1976

Contrast enhancement of cerebral infarcts in computed tomography.

Approximately 60% of cerebral infarcts between 1 and 4 weeks old may be enhanced by contrast material. A recent infarct can be missed if contrast material is not used; however, recent infarcts can also be partially obscured by the contrast medium, so that a precontrast scan is necessary. Infarcts, arteriovenous malformations, and gliomas may appear similar on the CT scan. Recent infarcts can have a significant mass effect (seen in 22% of cases), and their anatomical location and morphology may or may not be helpful in the differential diagnosis. Ipsilateral ventricular dilatation, homogeneous low-density areas, and sharp margins are usually found in older infarcts.

Adult↗
PubMed1975

Cerebellular calcification in tuberous sclerosis.

A rarely observed pattern of cerebellar calcification was noted in the skull roentgenograms of a child with tuberous sclerosis in the absence of cerebellar dysfunction. The computerized tomographic brain scan was useful in defining the extent of the cerebellar lesion and in detecting two additional foci of calcification that were not detected by standard roentgenographic methods.

Brain↗
PubMed1975

Localization with the EMI scanner.

Accurate localization of lesions seen on computerized tomographic scans obtained with the EMI unit is often difficult due to a paucity of reliable landmarks and to varying head angulation. A simple and accurate system of transposing the location of any particular lesion to a roentgenogram obtained with the scanner tube is described.

Adult↗
PubMedDate not supplied

High resolution T2-weighted imaging of the human brain using surface coils and an analytical reception profile correction.

High spatial resolution T2-weighted MR images of the human brain were obtained at 1.5 T. An optimized fast spin-echo (FSE) sequence and 1.5 g/cm gradients were used to obtain T2-weighted images in 4 to 9 minutes with an in-plane resolution of .27 mm and slice thicknesses from 1.5 to 3 mm. Phased arrays of surface coils were used as receivers, providing increased sensitivity but image intensities dependent on the reception profile of the coils. This image nonuniformity was removed by analyzing the data with a theoretical intensity correction algorithm developed in this laboratory. The FSE sequences, the specialized phased arrays of surface coils, and the intensity correction algorithm allowed improved visualization of nerves within the inner auditory canals and surface anatomy of the cerebral cortex. It is expected that this technique will be useful for clinical applications that require high resolution imaging of small, superficial structures of the brain.

Algorithms↗
PubMedDate not supplied

The use of computed tomography and ultrasonography in the evaluation of orbital masses.

The combined use of computed tomography scans with multiplanar reformation and ultrasonography makes it possible to locate orbital masses with a high degree of accuracy, and sometimes even to determine their histological nature without surgical biopsy. One of the unique features of computed tomography is its ability to distinguish both normal and abnormal structures of various tissue densities; this has contributed to very low false positive and false negative rates. Ultrasonography, while of limited use in the detection of posterior orbital lesions or lesions involving the orbital bones, provides an excellent cost-effective screening test for anterior and midorbit disease. It is also useful for the detection of extraocular muscle enlargement secondary to thyroid disease. In this article, a review of the characteristics and techniques of computed tomography and ultrasonography is followed by discussion of the advantages and limitations of each modality in the evaluation of six common types of orbital tumefaction.

Adult↗
PubMedDate not supplied

Cerebrospinal fluid flow artifact. A possible pitfall on fast-spin-echo MR imaging of the spine simulating intradural pathology.

We have noted that fast-spin-echo T2-weighted images of the cervical and thoracic regions of the spine can produce low-signal artifacts in the spinal subarachnoid space which might be misinterpreted as tumor or abnormal vascular flow voids. These are possibly related to complex cerebrospinal fluid pulsatile flow and should be recognized as artifactual by the radiologist.

Arteriovenous Malformations↗
PubMedDate not supplied

Postosteonecrotic osteoarthritis-like disorder of the femoral head of rats.

The femoral heads of 15 rats were studied histologically 3 months after the induction of ischaemic necrosis by incising the cervical periosteum and cutting the ligamentum teres. The epiphyses consisted of immature disorganized subchondral and trabecular bone. The inter-trabecular spaces contained fibrous or haematopoietic tissue. Residual necrotic bone was rare. There was marked osteoblastic and osteoclastic activity. The articular aspect of the heads showed a spectrum of changes, ranging from cartilaginous degeneration with fibrillation and loss of glycosaminoglycans to an eburnated and polished bony surface. In seven rats, transphyseal bridges connected the epiphyseal and metaphyseal bony trabeculae to each other. It is suggested that the postnecrotic reparative processes, including the resorption of the necrotic debris and its replacement by newly formed, weak bone, led to an osteoarthritis-like disorder. This healing pattern of the necrotic femoral head was reminiscent of the progressive remodelling that occurs in rings in femoral capital osteonecrosis of adult human patients and in Perthes's disease of children.

Animals↗