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Biomedical subjects

G Mimoun

Publications and source records attributed to G Mimoun.

At least 19 recordsLinked to original sources
PubMed2006

[Fundus flavimaculatus and choroidal neovascularization].

OBJECTIVE: Fundus flavimaculatus is an aspect of Stargardt disease, which is characterized by juvenile onset, rapidly progressive deterioration, and poor visual outcome due to atrophic areas or flecks. Recently, a late-onset form has been described, on the borderline with AMD. However, choroidal neovascular complications are not frequent and rarely described in Stargardt's disease. CASE REPORT: Late discovery of FFM in a patient over 50 years old. During her follow-up, she presented a decrease in visual acuity due to juxtafoveal choroidal neovascularization. In spite of laser treatment, a retrofoveal recurrence appeared, which was treated with perifoveal laser. DISCUSSION: Confusion between AMD and a late-onset Stargardt may occur because of their many clinical similarities. The population and the fundus results can be similar to AMD and an examiner may be confused. In the literature, choroidal neovascular complications appear in patients over 50 years of age who may suffer from AMD. In fundus flavimaculatus, pigmentary epithelium alterations are due to progressive lipoproteic scrap storage that predisposes to Bruch's membrane rupture and choroidal neovascularization. This physiopathology resembles the that of AMD. CONCLUSION: Choroidal neovascular complications are possible in late-onset Stargardt disease. Their appearance together may be greater than previously believed.

Choroidal Neovascularization↗
PubMed2006

[Surgical treatment of persistent macular edema in retinal vein occlusion].

INTRODUCTION: Persistent macular edema (ME) is the main cause of poor visual outcome in nonischemic retinal vein occlusion (RVO). The aim of this study was to evaluate the results of surgery in this disorder. PATIENTS AND METHODS: Retrospective nonrandomized comparative pilot study. Visual acuity measurement, fluorescein angiography, and optical coherence tomography were performed before and after treatment, at 3 months, 6 months, and 1 year. RESULTS: The study included 42 eyes: 15 eyes underwent vitrectomy with peeling of the posterior hyaloid and/or the internal limiting membrane, 19 received intravitreous injection of triamcinolone (IVT), and four had a combination of both treatments. In the vitrectomy group, 63% of the eyes showed a progressive decrease of ME throughout the year of follow-up (p<0.05 at 1 month and 1 year) and an increase in visual acuity (p<0.05 at 3 and 6 months); no complication occurred. In the IVT group, the eyes showed a rapid improvement in vision and in ME at 1 month (p=0.007 and p=0.001, respectively) but with a frequent ME recurrence at 4 months; however, 31% of eyes showed durable improvement. Complications after IVT were pseudo-endophthalmitis (one eye), transient hypertony (53%), and a full-thickness macular hole (one eye). In the group treated with vitrectomy combined with IVT, ME decreased rapidly and durably, but vision did not improve in this small subgroup of long-lasting RVO with prior pigment epithelial changes. CONCLUSION: In some eyes, vitrectomy seems to have a more durable effect than IVT alone. Further randomized and controlled studies are needed to confirm these results and to compare them to the natural course of the disease.

Adult↗
PubMed2001

A new approach of geodesic reconstruction for drusen segmentation in eye fundus images.

Segmentation of bright blobs in an image is an important problem in computer vision and particularly in biomedical imaging. In retinal angiography, segmentation of drusen, a yellowish deposit located on the retina, is a serious challenge in proper diagnosis and prevention of further complications. Drusen extraction using classic segmentation methods does not lead to good results. We present a new segmentation method based on new transformations we introduced in mathematical morphology. It is based on the search for a new class of regional maxima components of the image. These maxima correspond to the regions inside the drusen. We present experimental results for drusen extraction using images containing examples having different types and shapes of drusen. We also apply our segmentation technique to two important cases of dynamic sequences of drusen images. The first case is for tracking the average gray level of a particular drusen in a sequence of angiographic images during a fluorescein exam. The second case is for registration and matching of two angiographic images from widely spaced exams in order to characterize the evolution of drusen.

Fluorescein Angiography↗
PubMed1996

[Vitrectomy-laser-gas for treating optic disk pits complicated by serous macular detachment].

PURPOSE: Optic nerve pit is a rare congenital anomaly. In two third of the patients, the severity of the disease is increased by the apparition of a serous macular detachment, which may compromise the visual prognosis. The aim of this study is to propose a therapy appropriate to such complication. METHODS: A prospective study was performed including 10 patients with a serous macular detachment caused by optic nerve pit. All patients underwent intraocular surgery including vitrectomy, peripapillary photocoagulation and intravitreal injection of gas. The mean postoperative follow-up period was 9.5 months. RESULTS: Therapy success was based on anatomical and functional results. Serous macular detachment reattached in 7 patients out of 10 and a recurrence was observed in one case. Visual acuity improved from 0 to 18 lines of the EDTRS chart (mean increase: 6.7 lines). CONCLUSION: These results confirm that intraocular surgery including vitrectomy-photocoagulation-gas injection is a valuable treatment for serous macular detachment associated with optic nerve pit.

Adolescent↗
PubMed1994

Clinical risk factors for proliferative vitreoretinopathy after retinal detachment surgery.

PURPOSE: To identify the clinical risk factors for the development of severe proliferative vitreoretinopathy (PVR) after retinal detachment surgery. METHODS: A retrospective study of 1020 patients with either no PVR or with PVR of grade C1 or less at initial examination was conducted. After surgery, severe PVR was defined as grade C2 or worse. The data relating to 94 variables were evaluated by univariate analysis and stepwise logistic regression. RESULTS: Severe PVR developed after surgery in 107 patients (10.5%). Ten significant predictive variables were identified: minor intra- or postoperative hemorrhage, grade A preoperative PVR, preoperative choroidal detachment, giant tears, air tamponade, detachment involving more than 2 quadrants, cumulative break area larger than 3 optic disks, postoperative choroidal detachment, signs of uveitis at initial examination, and grade B preoperative PVR. CONCLUSION: The results indicate that in addition to the size of breaks, extent of detachment, and presence of preoperative inflammation or low-grade PVR, iatrogenic problems also are important factors in the pathogenesis of severe PVR after surgery for retinal detachment.

Aged↗
PubMed1994

[Collar-button choroidal melanoma. Anatomo-radiologic correlations].

Malignant melanomas of the choroid are the most frequent symptomatic eye tumours in adults. They often have a pathognomonic appearance, being collar-button or mushroom shaped due to rupture of Bruch's membrane by the tumoral mass. The ultrasonographic image of collar-button melanoma is well known: the head of the tumour is hyperechogenic and its base hypoechogenic. According to some authors, this is caused by difference in blood supply between the two parts. At MRI strongly pigmented melanomas emit a high-intensity signal on T1-weighted sequences and a low-intensity signal on T2-weighted sequences, but these characteristic features are inconstant. We present a case of collar-button melanoma explored by ultrasonography, colour Doppler Flow Imaging (CDFI) ultrasound and MRI, then enucleated. Flows and signals were different in front of, or behind the rupture of Bruch's membrane: ultrasounds showed a hyperechogenic image at the head and a hypoechogenic image at the base; on T2-weighted MRI sections intensity was greater in the head than in the base (head: 69 ms, base 180 ms) on CDFI, no flow was detectable in the head and very high flows were seen in the base of the tumour. Comparisons of these images with pathological findings, where there was no difference between head and base in melanin concentration and in cellular type (mixed or mainly epithelioid), led us to believe that the differences observed in images were essentially due to differences in blood supply between the two parts of the tumour constricted by the sides of the ruptured Bruch's membrane.

Bruch Membrane↗
PubMed1991

Clinical experience with digitized fluorescein angiography.

Directly acquired images of fluorescein angiography may be helpful in the treatment of retinal diseases. We report our experience with a commercially available image processing system. The major advantage of this system is that the pictures are instantly displayed on a television monitor allowing immediate treatment of the patient. However, further development of complementary software procedures is necessary to obtain an instrument capable of performing useful image-analysis of fundus lesions.

Equipment Design↗
PubMed1988

[Acute occlusion of a short posterior ciliary artery].

The angiographic aspect of a triangular syndrome examined at the acute stage is reported. They include exudative retinal detachment, non perfusion of the choroidal vessels in a large area, and dry leakage in the subretinal space. After healing, the findings are typical of temporal triangular syndrome.

Acute Disease↗
PubMed1984

[So-called rudimentary or nontransmural myocardial infarction. Coronary lesions, course and prognosis].

Eighty patients admitted to hospital between 1975 and 1980 for "non-transmural" myocardial infarction (72 men, 8 women, mean age 56 +/- 9 years) were studied. The diagnosis was based on a severe attack of pain of over 30 minutes duration, increased serum cardiac enzyme levels (CKMB greater than 24 U; SGOT greater than 60 U), pyrexia and signs of inflammation. The patients were divided into two groups according to their ECG changes: Group A: "rudimentary" infarction with prolonged T wave inversion from V1 to V5, narrow transient Q waves and reduction of R wave amplitude in the corresponding leads; Group B: persistant prolonged, intercritical ST depression greater than 2.5 mm (subendocardial infarct). All patients underwent selective coronary angiography and left ventriculography in the RAO projection within 15 days of admission. The angiographic data (coronary score, ejection fraction, alinetic perimeter) were compared to those of 2 randomly chosen control groups: Group C: 30 inferior wall infarcts with coronary angiography and regularly followed-up; Group D: 30 transmural anterior infarcts with coronary angiography, regularly followed-up. Four factors were analysed during follow-up: the incidence of death after discharge from hospital, transmural infarction, unstable angina and cardiac failure. All patients were treated medically (nitrate derivatives, betablockers, calcium antagonists). Sixteen patients in Group A (p less than 0,025) were operated and excluded from the prognostic study. The angiographic data showed a high incidence of isolated, severe LAD disease in Group A (59.2% of cases) and that multivessel disease was commoner in Group B (78.4%). A collateral circulation revascularising the LAD was observed in 42% of patients in Group A. (ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1983

[Myocardial infarction before the age of 35. Clinical and coronarographic aspects].

Myocardial infarction under the age of 35 is no longer a rarity. A series of 22 patients exhibited all the usual epidemiological, clinical and angiographic features of the disease: risk factors, predominantly excessive smoking associated with dyslipoproteinaemia in 50% of the cases; onset during exercise in one quarter of the cases, more frequently than in elderly people; and absence of significant lesions at angiography in one third of the cases. Angiography of the coronary arteries, performed in the early stages of infarction in 5 patients, demonstrated the presence of several factors in the pathogenesis of arterial occlusion in young people, i.e. thrombosis in almost every case, arterial spasm in 10% of the patients and atheromatous plaques with little or no stenosis in one half.

Adult↗
PubMedDate not supplied

Surgical removal of subfoveal choroidal neovascularization: visual outcome and prognostic value of fluorescein angiography and optical coherence tomography.

PURPOSE: To study the functional results of macular surgery and determine pre-operative features associated with better final visual outcome. METHODS: Forty-two consecutive patients underwent surgical removal of subfoveal choroidal neovascularization (CNV), related to age-related macular degeneration (AMD) in 8 eyes, degenerative myopia in 14 eyes, multifocal choroiditis (MFC) in 10 eyes, idiopathic CNV in 6 eyes and other etiologies in 4 eyes. Mean age was 49 years. Pre-operative visual acuity (VA) was 20/200 or less in 30 eyes (71.4%) and never better than 20/40. Fluorescein angiography was analyzed before and after surgery. Pre-operative optical coherence tomographs (OCT) were studied in a masked fashion. Mean follow-up was 12 months (range 4-48 months). RESULTS: Final VA was 20/200 or less in 25 eyes (60%). According to the CNV etiology, the percentage were 87.5%, 80%, 57.1% and 20% respectively in eyes with AMD, MFC, high myopia, and idiopathic or other diseases. Post-operative VA improved in 21 eyes (50%) but subsequently declined in 7% by the final examination. Patients younger than 50 years had better functional results (p=0.006). Lack of retinal pigment epithelium (RPE) changes on pre-operative angiography was correlated with good visual outcome (p<0.001). The OCT study confirmed some features already described and showed some different CNVpatterns: above and usually separated from the RPE, below and not separated from the RPE, and ungradable. Eyes with the first OCT pattern had the best visual outcome. Main complications included 4 (10%) retinal detachments and 9 (21%) recurrences. OCT was also useful to confirm CNV recurrences post-operatively. CONCLUSIONS: CNV surgical excision results vary depending on the underlying disease, the RPE and choriocapillaris function, and the features observed on pre-operative OCT images.

Adolescent↗
PubMedDate not supplied

[Significance of the digital image in the diagnosis and classification of macular drusen].

Macular drusen, hard or soft, have been often observed at the early stages of age-related macular degeneration. Clinically, it has been shown that soft drusen and macular subretinal new vessels are associated in a statistically significative manner. The question is to recognize and to determine drusen at greatest risk for developing choroidal neovascularization? To answer to this question, a method of digital images analysis of fluorescein angiography had been perfected. About ten eyes, preliminary results show, an objective and quantitative difference of the evolution of the grey level during the same angiogram between the different retinal structures. This method would bring a prognostic feature for the long term follow-up of patients with drusen.

Fluorescein Angiography↗