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Biomedical subjects

W E Lieb

Publications and source records attributed to W E Lieb.

At least 37 records · Page 2Linked to original sources
PubMed1994

Color Doppler imaging of arterial blood flow in central retinal vein occlusion.

PURPOSE: The hemodynamics of the retrobulbar arterial circulation of patients with central retinal vein occlusion were evaluated in order to better understand the pathophysiology of this disease. METHODS: Color Doppler imaging was used to measure the peak systolic velocity and vascular resistance (pulsatility index) in the retrobulbar arteries of involved eyes and clinically healthy fellow eyes of patients with central retinal vein occlusion and in the control eyes of age- and sex-matched healthy volunteers. RESULTS: Average peak systolic velocity was significantly lower and average vascular resistance was significantly higher in the central retinal artery of involved eyes of patients with central retinal vein occlusion compared with clinically healthy fellow eyes and compared with control eyes. There also was a trend toward higher vascular resistance in the central retinal artery of clinically healthy fellow eyes of patients with central retinal vein occlusion compared with control eyes. In the ophthalmic arteries and short posterior ciliary arteries, vascular resistance was significantly higher in both the involved eyes and clinically healthy fellow eyes of patients with central retinal vein occlusion compared with control eyes. CONCLUSION: Color Doppler imaging parameters of the central retinal artery circulation were abnormal in eyes with central retinal vein occlusion, suggesting impaired arterial blood flow associated with this disease. The high vascular resistance in the central retinal arteries, ophthalmic arteries, and short posterior ciliary arteries of both involved and clinically healthy fellow eyes of patients with central retinal vein occlusion suggests that diffuse small vessel disease may predate and contribute to the development of central retinal vein occlusion.

Blood Flow Velocity↗
PubMed1994

[Color duplex ultrasound. A new procedure in the study of orbital blood vessels in diabetic retinopathy].

Color Doppler imaging is a new noninvasive technique that allows the measurement of flow velocity in small orbital vessels (both arteries and veins). We compared 59 eyes with proliferative, 47 eyes with nonproliferative and 24 eyes with preproliferative diabetic fundus changes with a control group of non-diabetic patients. The central retinal artery, short ciliary artery and ophthalmic artery of each patient were examined. The systolic, diastolic and mean velocity was obtained for each vessel. Differences between the groups were most prominent in the central retinal artery. The perfusion velocity was significantly lower (P < 0.01) in proliferative eyes (Vsyst 5.7 +/- 1.9 cm/s) than in the control group (Vsyst 9.4 +/- 1.4 cm/s) or the nonproliferative eyes (Vsyst 8.3 +/- 1.9 cm/s). In the preproliferative group the velocity distribution varied widely. Consequently, no statistically significant difference could be deduced in relation to either the control group or the group with proliferative diabetic changes. In the ophthalmic artery and ciliary artery no group showed significant differences from normal. Our measurements indicate a definite correlation between the severity of diabetic retinopathy and a decreased flow velocity, particularly in the central retinal artery. Thus, color Doppler imaging may help to identify those diabetic patients who are at high risk of developing severe diabetic retinopathy so that early photocoagulation treatment can be initiated.

Adult↗
PubMed1994

[Ophthalmologic symptoms in meningioma of the orbits and in the anterior and medial cranial fossa].

UNLABELLED: The records of 182 patients treated for a meningioma of the orbit or the periorbital region between 1971 and 1989 were analyzed. PATIENTS: There were 138 women (76%) and 44 men (24%). Twenty patients had a meningioma of the optic nerve sheath, 78 patients a meningioma involving the sphenoid wing, 29 a meningioma within the sella region, 36 patients a meningioma of the anterior cranial fossa and 19 patients a meningioma of the medial cranial fossa. RESULTS: As an initial symptom 53% complained of decreased vision, 25% of headaches and 16% had exophthalmos. At the first ocular examination visual acuity was decreased below 0.1 in 22%. In 58 eyes we found papilledema and in 60 eyes optic atrophy. Other manifestations were visual field defects, ocular motility deficits in 20%. Histologically the meningiomas were most commonly of the endotheliomatous type (72%). In 23% of the patients, the tumor recurred, which manifested itself in a third by ocular symptoms.

Adult↗
PubMed1993

Optic nerve decompression improves hemodynamic parameters in papilledema.

PURPOSE: The purpose of this study is to examine changes in color Doppler imaging parameters before and after optic nerve sheath decompression (ONSD) for chronic papilledema caused by pseudotumor cerebri (PTC). METHODS: Color Doppler imaging was performed within 48 hours before surgery and within 48 hours after the procedure using a color Doppler unit with a 7.5-MHz phased linear transducer. Pulsed Doppler spectrum analyses were recorded digitally on videotape from the ophthalmic, central retinal, and short posterior ciliary arteries, using a 0.4 x 0.6-mm sample volume. RESULTS: Blood flow velocities in the ophthalmic, short posterior ciliary, and central retinal arteries of 24 eyes were significantly decreased compared with a healthy age-matched group. Eyes with visual acuities worse than 20/30 before surgery had significantly decreased velocities in the ophthalmic, short posterior ciliary, and retinal arteries, whereas in eyes with visual acuities better than 20/30, only the short posterior ciliary and central retinal arteries demonstrated decreased velocities. In addition, Gosling's pulsatility index was increased for the central retinal artery but not the ophthalmic or short posterior ciliary arteries. Thirteen eyes improving in visual acuity and field after ONSD demonstrated significant improvement in all color Doppler imaging parameters for the short posterior ciliary arteries. The ophthalmic artery diastolic velocity also increased significantly but the central retinal artery parameters did not change. The eyes that remained stable or worsened did not demonstrate significant postoperative changes. CONCLUSION: These results suggest that some of the visual loss from chronic papilledema may be due to ischemia, and worsening visual acuity correlates with greater impairment of the retrobulbar circulation. One of the mechanisms by which ONSD improves visual function may be reversal of this ischemic process.

Arteries↗
PubMed1993

Color Doppler ultrasonography of the eye and orbit.

Color Doppler imaging is the recent development in ultrasonography that allows simultaneous two-dimensional structural imaging in Doppler evaluation of blood flow. With this technique, it is possible for the first time to indirectly display the fine orbital vessels such as the ophthalmic artery and its branches, the central retinal artery, the posterior ciliary artery, and the lacrimal artery. Also, the display of venous structures such as the superior ophthalmic vein, the vortex vein, and the central retinal vein is possible. In addition to the qualitative display of those vessels, the hemodynamics in those vessels can be quantitatively assessed by looking at the Doppler spectrum and determining flow velocities during various periods of the cardiac cycle. This technique is now being used in ophthalmology to evaluate orbital tumors and vascular lesions, intraocular tumors, carotid-cavernous-sinus-fistulas, and hemodynamic changes in patients with retinal vascular disease such as central retinal artery occlusion, central retinal vein occlusion, and diabetic retinopathy.

Blood Flow Velocity↗
PubMed1992

Color Doppler imaging of the ocular ischemic syndrome.

PURPOSE: This study describes hemodynamic characteristics of the ophthalmic, central retinal, and posterior ciliary arteries in 16 eyes of 11 patients with the ocular ischemic syndrome. Understanding the hemodynamic characteristics of the retrobulbar circulation may elucidate the natural history and pathophysiology of the ocular ischemic syndrome and perhaps form the basis for rational treatment of this condition. METHODS: Color Doppler imaging, a procedure that permits rapid noninvasive imaging of the ophthalmic, central retinal, and posterior ciliary arteries, was used to quantitate peak systolic blood flow velocities and vascular resistance (pulsatility index) within these vessels in study group eyes and in an age-matched control population. RESULTS: We demonstrated markedly reduced ocular ischemic syndrome central retinal and posterior ciliary artery peak systolic velocities compared with control group eyes. Central retinal and posterior ciliary artery vascular resistance (pulsatility index) was greater in ocular ischemic eyes versus control group eyes. Reversal of ophthalmic artery blood flow was detected in 12 of 16 ocular ischemic syndrome eyes. Study group eyes with poor vision had no detectable posterior ciliary arterial blood flow. CONCLUSION: Color Doppler imaging quantitates hemodynamic characteristics of the retrobulbar circulation in the ocular ischemic syndrome. There is markedly reduced peak systolic velocity and increased vascular resistance in ocular end arteries such as the central retinal and posterior ciliary arteries. Ophthalmic artery reversal of flow seems to represent collateral blood flow to lower resistance vascular beds. Posterior ciliary artery hypoperfusion may correlate with poor vision in the ocular ischemic syndrome.

Aged↗
PubMed1992

Color Doppler imaging of the eye and orbit. A synopsis of a 400 case experience.

Color Doppler imaging (CDI) is a recent advance in ultrasonography that allows simultaneous two-dimensional imaging of structure and blood flow. Doppler information is superimposed in color over a conventional gray-scale ultrasound image. Using this technique we have examined 400 eyes. The central retinal artery, posterior ciliary arteries, ophthalmic artery, the central retinal vein and the vortex veins could be located in all normal eyes. Using the color image as a guide, Doppler spectral analysis is used for quantitative assessment of blood flow velocity in these vessels. We also studied patients with intraocular tumors, arterial and venous retinal occlusions, orbital vascular anomalies and tumors. Color Doppler imaging is a new and promising modality for the study of ocular and orbital hemodynamics.

Blood Flow Velocity↗
PubMed1991

Color Doppler imaging. A new noninvasive technique to diagnose and monitor carotid cavernous sinus fistulas.

Color Doppler imaging is a recent development in ultrasonography that allows for simultaneous two-dimensional structural imaging and Doppler evaluation of blood flow. With this technique, one patient with a traumatic carotid cavernous sinus fistula and two patients with spontaneous dural cavernous arteriovenous malformations were evaluated. Color Doppler imaging demonstrated a dilated superior ophthalmic vein with arterialized blood flow in all three patients. In two cases the diagnosis was confirmed by angiography, and in one of these cases the fistula was occluded with a detachable balloon catheter. Postembolization color Doppler imaging revealed return of normal venous flow in the superior ophthalmic vein. This technique offers a noninvasive means to confirm the clinical diagnosis and to track the hemodynamics of these arteriovenous fistulas. In certain cases, color Doppler imaging may eliminate the need for computed tomography and magnetic resonance imaging in the evaluation of suspected arteriovenous malformations of the orbit.

Aged↗
PubMed1991

Color Doppler imaging of the eye and orbit. Technique and normal vascular anatomy.

Color Doppler imaging is a recent advance in ultrasonography that allows simultaneous two-dimensional imaging of structure and blood flow to be performed. Doppler information is superimposed in color over a conventional gray-scale ultrasound image. Using this technique, we examined 40 normal eyes. The central retinal artery, posterior ciliary arteries, ophthalmic artery, and central retinal vein could be located in all patients. Using the color image as a guide, Doppler spectral analysis allows quantitative assessment of blood flow velocity in these vessels. Color Doppler imaging is a new modality for the study of ocular and orbital hemodynamics.

Adult↗
PubMed1991

Identification of an S-antigen-like molecule in Drosophila melanogaster: an immunohistochemical study.

Vision is a highly complex process common to many vertebrate and invertebrate species. The visual system of Drosophila represents a valuable model in which to study this process since its chromosomal makeup has been well mapped and many mutants containing specific photoreceptor defects have been described. S-antigen is a well-characterized photoreceptor cell protein which plays a fundamental role in the visual process. In this study, we used a panel of four monoclonal antibodies (MAbs) specific for amino, mid and carboxy terminal amino acid sequences in S-antigen in order to examine S-antigen immunoreactivity in the Drosophila visual system. Two MAbs, MAb5C6.47 and MAbC10-C10, localized S-antigen to the retinules and ocelli. In contrast, MAbA2-G5 and MAbA9-C6 did not stain. The presence and strong antigenic similarity of an S-antigen homolog in Drosophila suggests that in both vertebrates and invertebrates S-antigen plays a major role in the regulation of the phototransduction of vision.

Amino Acid Sequence↗
PubMed1991

Color Doppler imaging provides accurate assessment of orbital blood flow in occlusive carotid artery disease.

Color Doppler imaging was used to evaluate the hemodynamics of the ophthalmic vasculature in a case of complete internal carotid artery occlusion. This procedure, which allows rapid, noninvasive imaging, showed a partial ophthalmic artery obstruction with absent flow in the central retinal artery, central retinal vein, and nasal posterior ciliary arteries. Although altered perfusion of the retinal vessels may be evaluated clinically, assessment of blood flow in the ophthalmic and ciliary arteries previously could be evaluated only indirectly by intravenous fluorescein angiography. The color Doppler imaging findings were confirmed by intravenous fluorescein angiography and carotid arteriography. Color Doppler imaging represents a noninvasive method to diagnose abnormal blood flow of the ophthalmic artery and its branches and to evaluate serial changes of the circulation in a noninvasive manner.

Adult↗
PubMed1990

Multiple orbital neurofibromas unassociated with von Recklinghausen's disease.

A 58-year-old man with a 10-year history of right periorbital pain treated with multiple analgesics presented with slowly progressive exophthalmos of the right eye. Orbital imaging studies disclosed three separate well-defined tumors, located in the temporal fossa, the intraconal space, and within the floor of the orbit. All three tumors were removed intact and proved on histopathologic evaluation to be localized neurofibromas. The patient had complete relief of the chronic pain following removal of the tumors. We emphasize that the unusual occurrence of multiple circumscribed orbital tumors should suggest the diagnosis of neurofibroma even in the absence of von Recklinghausen's neurofibromatosis.

Humans↗
PubMed1990

Myxoma of the orbit: a clinicopathologic report.

A 27-year-old white man developed proptosis of his left eye over a period of 2 years. It was associated with vertical diplopia and displacement of the left globe down and laterally. Ultrasonography showed a cystic mass in the superior orbital region. Computed tomography (CT) demonstrated a solid, well-defined lesion behind the globe displacing the optic nerve medially. A transfrontal craniotomy revealed a nodular mass in the posterior and superior orbit, which extended anteriorly up to the globe. Histopathology, immunohistochemistry, and transmission electron microscopy proved the tumor to be a myxoma.

Adult↗
PubMed1990

Color Doppler imaging in the management of intraocular tumors.

Forty-four intraocular mass lesions were studied using a new, non-invasive ultrasound technique known as color Doppler imaging (CDI). This technique displays color-encoded Doppler flow information throughout a two-dimensional gray scale image thus providing selective analysis of Doppler spectra in small vessels using pulsed Doppler. Abnormal Doppler shifts were demonstrated within 39 neoplastic lesions studied, but Doppler shifts could not be detected in three tumor-simulating lesions. In a group of 12 choroidal melanomas studied after radiation therapy, lower Doppler shifts were seen compared with a group of 28 tumors before therapy. This change in Doppler shift may reflect the decreased vascular supply of the tumor. Color Doppler imaging may be of value as an additional useful tool in the diagnosis and management of intraocular tumors.

Adolescent↗