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A case of bilateral ophthalmic artery aneurysm of traumatic origin is discussed. The patient presented with progressive loss of vision, memory deficit, and expressive aphasia. A computed tomographic scan revealed enhancing lesions near the region of the optic chiasm. The diagnosis of cerebral aneurysm was confirmed by cerebral angiography. At operation, bilateral ophthalmic artery aneurysms were successfully clipped.
Hypothetical schemes for neural representation of visual information can be expressed as explicit image codes. We may test whether a given code is sufficient, in the sense of retaining all the information that the human perceives, and necessary, in the sense of retaining only that information. The latter is a test of efficiency. Here, we explore a code modeled on the simple cells of the primate striate cortex. The Cortex transform maps a digital image into a set of subimages (layers) that are bandpass in spatial frequency and orientation. The layers are sampled so as to minimize the number of samples and still avoid aliasing. Samples are quantized in a manner that exploits the bandpass contrast-masking properties of human vision. The entropy of the samples is computed to provide a lower bound on the code size. Finally, the image is reconstructed from the code. We devise psychophysical methods for comparing the original and reconstructed images to evaluate the sufficiency of the code. When each resolution is coded at the threshold for detection artifacts, the image-code size is about 1 bit/pixel.
OBJECTIVE: To describe a case of solitary intrasellar plasmacytoma in a patient with a preoperative diagnosis of a nonfunctioning pituitary adenoma. METHODS: A case of a solitary intrasellar plasmacytoma is presented, in which the clinical and laboratory findings are detailed and the response to treatment is discussed. Pertinent reports from the literature are reviewed. RESULTS: A 53-year-old woman came to the neurology clinic with complaints of frontal headaches and intermittent blurry vision. Physical examination showed no remarkable findings. Computed tomography revealed an enhancing sellar and suprasellar mass, with extension into the sphenoid and cavernous sinuses. The patient had a preoperative diagnosis of a clinically nonfunctioning pituitary adenoma and underwent transsphenoidal resection. The biopsy specimen was heavily infiltrated with abnormal plasma cells, which stained exclusively for lambda light chain immunoglobulins. An extensive investigation failed to show evidence of multiple myeloma. In view of these findings, the diagnosis of solitary extramedullary plasmacytoma was made. Postoperatively, the patient received radiotherapy to the pituitary and has remained free of disease for 7 years. Review of the world literature disclosed only 17 previous reports of patients in whom a solitary plasmacytoma or multiple myeloma first appeared as a sellar mass. In each case, the plasmacytoma mimicked a clinically nonfunctioning pituitary adenoma. CONCLUSION: Parasellar plasmacytomas are often mistaken for a nonfunctioning pituitary adenoma. The diagnosis is difficult to make in the absence of overt systemic myeloma. Nevertheless, normal pituitary function associated with severe destruction of the pituitary fossa, cranial neuropathies, and diabetes insipidus are clues that the primary lesion is outside the pituitary gland itself. The current patient is unique in terms of prolonged survival in the absence of systemic myeloma. Perhaps those patients with progression of disease did not have extramedullary tumors because such lesions rarely progress to overt myelomatous disease.
OBJECTIVE: To review gonadotropin-secreting pituitary tumors and report the rare case of one of these tumors that caused high serum testosterone concentrations, followed by hypogonadism after hypophysectomy. METHODS: A case report is presented of a 61-year-old man who had decreased vision in his left eye, found by computed tomography of the sella to be attributable to a soft tissue pituitary mass with upward extension that caused elevation and deviation of the optic chiasm. Endocrine and pathologic evaluations are presented, and the treatment and follow-up course are discussed. RESULTS: Endocrine evaluation revealed a serum follicle-stimulating hormone (FSH) of 72.48 mIU/mL, luteinizing hormone (LH) of 31.65 mIU/mL, prolactin of 26.42 ng/mL, and total testosterone of 15.24 ng/mL (all values higher than the normal ranges). A soft tissue mass (3.2 by 2.5 by 1.2 cm) with negative immunocytochemical staining for prolactin and growth hormone but positive staining for synaptophysin, FSH, and LH was removed. One month postoperatively, the patient's chief complaints were a decrease in penile size and erectile dysfunction. Endocrine evaluation revealed a decreased LH of <0.3 mIU/mL, total testosterone of <0.2 ng/mL, and FSH of 4.3 mIU/mL. Three months later with testosterone replacement therapy, testosterone levels normalized, LH was <0.3 mIU/mL, and FSH was 3.9 mIU/mL. Thyroid function and adrenal function were normal before and after surgical intervention. CONCLUSION: This rare case indicates that gonadotropin tumors can produce a functional LH that can increase serum testosterone levels.
This article discusses The Computer-based Patient Record: An Essential Technology for Healthcare, the eagerly awaited report from the Institute of Medicine. The report presents the conclusions and recommendations of the multidisciplinary committee convened to explore how patient records could be improved, a project supported in part by AMRA.
Using the Pioneer space program as a metaphor for the spirit of adventure, the vision and the innovation embodied by all Computers in Healthcare Pioneers, CIH names four new Pioneers for 1992. These new Pioneers as well as our 13 current Pioneers will be honored at the Seventh Annual Computers in Healthcare Conference and Exposition May 27 and 28 in San Diego.
Central neurocytoma is a rare intraventricular tumor recently accepted as a clinicopathological entity. A 21-year-old female was admitted with three-year history of episodic headaches and vomiting, and with rapid deterioration of her left vision over two weeks prior to admission. Computed tomography (CT) scan revealed a marked hydrocephalus and an isodense, mildly enhancing mass in the left lateral ventricle. On magnetic resonance imaging (MRI) scan, T1-weighted images revealed an intraventricular mass of slightly high intensity signal, which contained areas of low intensity signal representing multiple intratumoral cysts. The tumor showed a minimal enhancement with Gd-DTPA. A diagnosis of central neurocytoma was confirmed by an electron-microscopic study of a surgical specimen; there were numerous neuronal cell processes containing microtubules and dense-core vesicles, and a few small intercellular junctions were also identified.
The course of endocrine ophthalmopathy was investigated on the basis of clinical and biochemical parameters and in relation to different therapeutic strategies. A retrospective appraisal was made of 297 patients (44 +/- 14 yr, 249 women) with inclusion of anamnestic and clinical data as well as the results of computer tomography. At the beginning of therapy, 253 patients were hyperthyroid, 36 were euthyroid and eight were hypothyroid. The HLA typing carried out in 89 patients showed the phenotypes B8 and DR3 in 32% and 42% of the cases, respectively. Raised microsomal antibodies were present in 56% of the patients and there were raised thyroglobulin antibodies in 19%. Sixty-three % of the patients received immunosuppressants in the course of therapy: glucocorticoids in all cases, nonsteroid immunosuppressants in 15%. Eight % of the patients were irradiated retrobulbarly. The inflammatory parameters could be favorably affected, whereas eye muscle involvement and bulbar protrusion proved to be more resistant to therapy. In patients with combined immunosuppressant therapy or steroids + retrobulbar radiation, there were unequivocal successes with regard to the proptosis, vision and intraocular pressure. None of the strategies applied constitutes an optimal treatment with regard to the long-term course. Following therapy, there is an improvement of endocrine ophthalmopathy, but not complete healing.
The group of six patients in this study experienced delayed visual loss following head trauma. Visual loss occurred from 1 day to 13 years after the initial injury. All patients suffered indirect trauma to the internal carotid artery resulting in formation of either an aneurysm or pseudoaneurysm or a carotid-cavernous fistula. Review of the radiologic and clinical findings was performed in six patients. The diagnosis was established by computed tomography, magnetic resonance imaging, and angiography. All patients had follow-up clinical evaluation and imaging studies. Treatment by neurosurgical or interventional neuroradiologic procedures resulted in significant visual improvement in five patients. Different pathophysiologic mechanisms could be correlated with the delayed visual loss produced by the two types of lesions. The pathologic changes associated with the aneurysms/pseudoaneurysms included direct compression of optic nerves and/or chiasm and intracranial hematoma. A carotid-cavernous fistula caused delayed visual loss by either hematoma at the orbital apex or compression of the chiasm and/or optic nerves by saccular dilatation of the cavernous sinus. The delayed onset of decreased vision following head trauma should alert the physician to the possibility of a traumatic aneurysm/pseudoaneurysm or a carotid-cavernous fistula. Different neuro-ophthalmologic symptoms can usually be correlated with the pathologic changes demonstrated by neuroimaging procedures.
Fusional vergence eye movements are controlled by a fast-acting mechanism that aligns the eyes in response to retinal image disparity and a slow-acting mechanism that sustains binocular alignment. These two control mechanisms are distinguished by their decay time constants and stimuli. Fast fusional vergence responds to retinal image disparity, and slow fusional vergence responds to the effort or output of the fast control mechanism. Fixation disparity is modeled as a steady-state error of fast fusional vergence. Fixation disparity is shown to be inversely related to prism adaptation, a manifestation of slow fusional vergence, in normal but not abnormal binocular vision. Sensory factors such as interocular suppression influence the magnitude of fixation disparity in strabismus. Clinical implications concerning the relation between fixation disparity and heterophoria in normal and abnormal binocular vision are discussed.
OBJECTIVE: To describe the clinical, ophthalmological, endocrinological and radiological features of 10 Saudi children with the syndrome of septo-optic dysplasia and hypothalamic hypopituitarism. METHODS: All patients underwent complete ophthalmological and endocrinological evaluation at the Pediatric Endocrine Clinics, King Faisal Specialist Hospital and Research Center and King Fahad National Guard Hospital, Riyadh, Kingdom of Saudi Arabia, from October 1999 through to May 2004. The hormonal evaluation included growth hormone, adrenocorticotrophic hormone, thyroid stimulating hormone, gonadotropin and anti diuretic hormone testing, and the neuroradiological assessment included brain magnetic resonance imaging or computed tomogram scanning, or both. RESULTS: The current age of patients ranged from 18- months to 5-years. The mean age of initial presentation for endocrine evaluation was 14-months. Hormonal studies indicated that all children had multiple pituitary hormone deficiencies (2 or more of the pituitary hormones were deficient). Ten children had growth hormone deficiency, 8 had thyroid stimulating hormone deficiency, 8 had adrenocorticotrophic hormone deficiency, 2 children were suspected to have gonadotropin deficiency and central diabetes insipidus was present in one patient. Pendular nystagmus and impaired vision were common initial signs. All children had bilateral optic nerve hypoplasia. Neuroradiologic findings were variable. Eight children had absent septum pellucidum, 3 had pituitary gland hypoplasia, 2 had pituitary stalk dysplasia (pituitary stalk was either attenuated or not visualized), 2 had absent corpus callosum and one had absent posterior pituitary high intensity signal. All patients were replaced with appropriate hormonal replacement therapy. Two male children had micropenis which responded to testosterone therapy. CONCLUSION: The syndrome of septo-optic dysplasia is commonly associated with hypothalamic hypopituitarism including anterior and posterior pituitary hormonal deficiencies. Early diagnosis of this syndrome is critical as the hormonal deficiencies can be life threatening.
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By the 1960s it was evident from neuroanatomy that there were extensive recurrent interactions, both excitatory and inhibitory, among visual cortical neurons. Nevertheless, the psychophysical discovery of 'spatial-frequency channels' gave rise to a decade in which parallel, independent channels were thought to subserve early spatial vision. Recent work, however, has clearly demonstrated that early visual channels do not perform a Fourier or wavelet decomposition of the image. Instead, they interact through a variety of nonlinear pooling mechanisms. Such nonlinear interactions perform important computations in texture perception, stereopsis, and motion and form vision.
BACKGROUND: Dynamic retinoscopy is a common clinical test for assessment of visual function in patients with symptoms related to computer use. It has been suggested that performing dynamic retinoscopy with a fixation target resembling a computer screen may be valuable in the examination of computer users. However, such targets differ in luminance and other characteristics from the printed paper test cards typically used for dynamic retinoscopy. METHOD: To address the effect of varying test targets on dynamic retinoscopy results, this study compared lag of accommodation results from dynamic retinoscopy with three different fixation targets: (a) a printed paper target, (b) a video display terminal, and (c) the PRIO vision testing device, which is designed to simulate a computer screen. MEM (monocular estimate method) dynamic retinoscopy was performed with the print target and with the PRIO device. RESULTS: The difference between results with the different test conditions were generally small, with a statistically significant 0.32 D lower lag found on MEM retinoscopy with the PRIO target IMEM-PRIO) than on MEM retinoscopy with a print target (MEM-PRINT). Mean lag measurements on MEM with a print target and on Nott retinoscopy with the video display terminal (NOTT-VDT) were only 0.04 D different. The 95% limits of agreement for the difference between MEM-PRINT and MEM-PRIO (+/- 0.6 D) was similar to the 95% limits of agreement for the interexaminer reliability of the two procedures (+/- 0.6 D for MEM-PRINT and +/- 0.7 D for MEM-PRIO). CONCLUSION: There was a small but statistically significant difference in lag of accommodation measured with MEM dynamic retinoscopy on the PRIO testing device when compared to a print card.
The authors used the discrimination method--pseudoisochromatic phases and the comparison-assortment method for the chromatic sense examination in a group of subjects working in the motor transport and chemical textile dying. Computer programs were devised for examination data processing and for diagnosis display. After each testing, the data of each subject are added to the patient's card to be subsequently looked up and used for statistics.
We demonstrate how to produce complex image transformations of bitmap files for vision experiments using the Cogimatic Vision Starter Kit (VSK) library of mathematical routines along with Visual Basic, C++, or the Delphi Pascal compiler. Implementing this system on an IBM-compatible PC running Windows 95, 98, or NT4 enables researchers to quickly and economically manipulate images for vision research. The VSK includes a simple stand-alone image-processing application. In addition, VSK has the ability to automate image transformations and to fully integrate image processing into new experimental software on the PC platform.