Search PubMed⌕ Search

Biomedical subjects

B Yazici

Publications and source records attributed to B Yazici.

15 recordsLinked to original sources
PubMed2006

X-ray imaging optimization using virtual phantoms and computerized observer modelling.

This study develops and demonstrates a realistic x-ray imaging simulator with computerized observers to maximize lesion detectability and minimize patient exposure. A software package, ViPRIS, incorporating two computational patient phantoms, has been developed for simulating x-ray radiographic images. A tomographic phantom, VIP-Man, constructed from Visible Human anatomical colour images is used to simulate the scattered portion using the ESGnrc Monte Carlo code. The primary portion of an x-ray image is simulated using the projection ray-tracing method through the Visible Human CT data set. To produce a realistic image, the software simulates quantum noise, blurring effects, lesions, detector absorption efficiency and other imaging artefacts. The primary and scattered portions of an x-ray chest image are combined to form a final image for computerized observer studies and image quality analysis. Absorbed doses in organs and tissues of the segmented VIP-Man phantom were also obtained from the Monte Carlo simulations. Approximately 25,000 simulated images and 2,500,000 data files were analysed using computerized observers. Hotelling and Laguerre-Gauss Hotelling observers are used to perform various lesion detection tasks. Several model observer tasks were used including SKE/BKE, MAFC and SKEV. The energy levels and fluence at the minimum dose required to detect a small lesion were determined with respect to lesion size, location and system parameters.

Computer Simulation↗
PubMed2006

Scar formation after stereotactic vacuum-assisted core biopsy of benign breast lesions.

AIM: To evaluate scar formation of impalpable breast lesions with benign histological outcome using stereotactic 11-gauge vacuum-assisted core biopsy (VACB). MATERIALS AND METHODS: Two hundred and ten lesions with benign histology for which follow-up mammograms were available, were assessed for scar formation at the biopsy site. All biopsies were performed using stereotactic VACB with 11-gauge needle. The incidence of post-biopsy scar formation and the number of specimens removed were determined. RESULTS: In 4.3% (9/210) of the lesions for which a biopsy was performed with 11-gauge directional vacuum-assisted technique, the follow-up mammogram revealed a scar formation. Of these, six were minimal scars, two were moderate scars and one was a marked scar. Minimal and moderate scars were diagnosed on imaging only. However, the case with marked scar formation required tissue diagnosis to rule out malignancy. CONCLUSION: Although uncommon, scar formation can be seen in the follow-up mammograms after percutaneous breast biopsies. It is important that the radiologist interpreting follow-up mammograms is aware of the features of this lesion and its relationship to the biopsy procedure.

Biopsy, Needle↗
PubMed2006

Effects of tibolone on blood flow resistance and intima-media thickness of the carotid arteries: effect of time since menopause.

OBJECTIVE: The aim of this prospective study was to evaluate the effects of tibolone on carotid atherosclerosis in healthy postmenopausal women. METHODS: Twenty-five healthy postmenopausal women were included in the study. Patients received tibolone 2.5 mg daily for 6 months. Resistance indices of the common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA) and vertebral arteries, and intima-media thickness of the CCA were measured both at baseline and at the end of the study with ultrasonography. RESULTS: No significant differences were observed in the resistance indices of the CCA, ICA, ECA and vertebral arteries, as well as intima-media thickness of CCA at 6 months in comparison with baseline. Tibolone significantly improved the intima-media thickness of the CCA of women who were less than 18 months since menopause. CONCLUSION: Overall, these results demonstrate no significant effects of tibolone on either intima-media thickness or blood flow resistance in the carotid arteries in postmenopausal women. However, the results suggest that tibolone may have a positive effect on the vascular system if commenced within 18 months since menopause; this warrants further investigation.

Carotid Arteries↗
PubMed2005

Hump-shaped corpus callosum.

Developmental anomalies of the corpus callosum are agenesis, hypogenesis, or hypoplasia. In this case, a hump-shaped anomaly was present in the body of the corpus callosum. The rostrum, genu, and splenium of the corpus callosum were normal. In addition, a split was present within this hump, connecting the lateral ventricles. No additional anomalies were present. This type of anomaly has not been previously reported in the literature.

Agenesis of Corpus Callosum↗
PubMed2003

Comparison of ambulatory blood pressure values in patients with glaucoma and ocular hypertension.

PURPOSE: To compare systemic arterial blood pressure (BP) and nocturnal hypotension in patients with normal-tension glaucoma (NTG), high-tension glaucoma (HTG), and ocular hypertension. METHODS: Systemic BP was recorded by a portable automated BP monitoring device every 20 min during the day and every 30 min at night in patients with NTG (n=18), HTG (n=22), and ocular hypertension (n=19). Mean systolic, diastolic, and mean arterial BPs were calculated for 24 h, during the day and at night. The mean and maximum nocturnal dip rates were determined for each patient. The number of readings that declined below 90 mmHg for systolic BP and below 60 and 50 mm Hg for diastolic BP was recorded for each group. Statistical significance was set at P<0.05. RESULTS: Minimum, maximum, and mean values of the systolic, diastolic, and mean arterial BPs were not significantly different among groups. There was no difference among groups in the nocturnal dip percentages of systolic and diastolic BPs. The number of systolic BP readings below 90 mmHg was significantly higher in the NTG group compared with the other groups (P<0.001, chi(2) test). CONCLUSION: There may not be any difference among NTG, HTG, and ocular hypertension patients in terms of mean ambulatory BP values. On the other hand, when each individual's ambulatory reading is reviewed, readings may reveal that excessive and repetitive nocturnal drops occur more frequently in some patients with NTG. These hypotensive episodes may be related to the development of glaucomatous damage.

Adult↗
PubMed2002

Prediction of visual outcome after retinal detachment surgery using the Lotmar visometer.

AIM: To evaluate whether an achromatic interferometer, the Lotmar visometer, is useful in predicting postoperative visual outcome in patients with primary rhegmatogenous retinal detachment (RD) involving the macula. METHODS: This prospective study included 40 eyes of 40 non-consecutive patients with macula-off RD. The eyes were phakic or pseudophakic, had a clear optical media, and had a measurable potential vision on preoperative visometric examination. Preoperative variables included Snellen visual acuity, duration of macular detachment, extent of RD, and visometric potential acuity. Reattachment surgery consisted of radial scleral buckling in 33 patients, circumferential scleral buckling and encircling in seven patients, and subretinal fluid drainage in 10 patients. Retinal breaks were treated with cryotherapy or laser photocoagulation. Patients were followed up for at least 6 months after uncomplicated surgery. Best corrected visual acuity measured at any time during follow up was correlated with the preoperative variables. RESULTS: Preoperative visual acuity was less than 20/200 in 37 (93%) of 40 patients. Potential visual acuity of 20/200 or better was measured using the Lotmar visometer in 37 patients (93%). Postoperative visual acuity was correlated significantly with duration of macular detachment (r=0.55; p<0.001), and extent of RD approached statistical significance (r=0.31; p=0.05). There was a higher correlation between postoperative visual acuity and the visometric measurements (r=0.61; p<0.001). CONCLUSIONS: The Lotmar visometer may be a valuable method to estimate visual outcome after uncomplicated scleral buckling surgery in patients with RD involving the macula.

Adult↗
PubMed2001

Treatment of nasolacrimal duct obstruction in adults with polyurethane stent.

PURPOSE: To evaluate the efficacy of polyurethane nasolacrimal duct stents in the treatment of epiphora resulting from primary acquired nasolacrimal duct obstruction in adults. MATERIALS AND METHODS: In 25 patients (21 women and four men with mean age of 44 years, range 20 to 74 years) with nasolacrimal duct obstruction, 28 hollow polyurethane stents designed by Song and associates were placed under fluoroscopic guidance. The obstruction was complete in 20 lacrimal drainage systems and partial in eight. The lacrimal sac size was normal or large on dacryocystogram in all lacrimal drainage systems. A Ritleng probe was introduced through the upper punctum and advanced past the obstruction. A guide wire with a flexible tip was then introduced through the probe, over which the stent was advanced in retrograde fashion and placed into the lacrimal sac and nasolacrimal duct. Clinical success was defined by the demonstration of a completely patent lacrimal drainage pathway through saline irrigation and no or minimal complaint of epiphora. RESULTS: Stent placement was technically successful in 26 of 28 lacrimal drainage systems (93%). The mean time of fluoroscopy screening was 3.2 minutes (range, 1.4 to 5.8 minutes). The overall success rate was 82% (23 of 28 lacrimal drainage systems). Two stents were completely occluded. In one lacrimal drainage system with minimal epiphora, the stented drainage pathway was partially occluded. The patients were followed up from 4 to 22 months (mean, 7.2 months). CONCLUSIONS: Retrograde placement of a hollow polyurethane nasolacrimal duct stent is a technique that is simple and well tolerated by patients. This method achieves a high success rate and may be suggested as a nonsurgical procedure for adults with primary nasolacrimal duct obstruction and proper lacrimal sac size. The Ritleng probe facilitates the procedure.

Adult↗
PubMed2001

Lacrimal sac dacryoliths: predictive factors and clinical characteristics.

OBJECTIVE: Lacrimal sac dacryoliths are often diagnosed during dacryocystorhinostomy (DCR), although their cause is unclear. Several factors have been suggested to predispose to dacryolith formation. The clinical presentation of nasolacrimal duct obstruction (NLDO) may differ if associated with a dacryolith. Our study evaluated specific risk factors related to dacryolith formation and how the clinical presentation of patients with dacryoliths differs from patients with primary acquired NLDO who undergo DCR. DESIGN: Retrospective, comparative, interventional case series. PARTICIPANTS/INTERVENTION: One hundred thirty-eight consecutive patients with NLDO who underwent DCR (163 total DCR cases) between 1993 and 1998. MAIN OUTCOME MEASURES: We evaluated the frequency of dacryolith formation for all DCR cases. For 115 patients with primary acquired NLDO, we statistically compared the patients with dacryoliths (n = 12) to those without (n = 103) for several variables related to clinical history and presentation. RESULTS: The overall frequency of dacryoliths was 12 of 163 (7.4%) for all DCR cases and 12 of 138 (8.7%) for all patients. All patients with dacryoliths were in the subgroup of 115 patients with primary acquired NLDO, and the frequency in that subgroup was 12 of 115 (10.4%). There was no statistical difference between the group of patients with dacryoliths and those without dacryoliths for age, duration of epiphora, history of acute dacryocystitis, or previous use of antiglaucomatous topical medications. Male gender was more likely to be associated with dacryoliths (P = 0.004), as was initial presentation with lacrimal sac distension (P < 0.001). Partial nasolacrimal obstruction on lacrimal irrigation approached statistical significance for dacryolith formation (P = 0.08), as did a history of cigarette smoking (P = 0.09). CONCLUSIONS: In patients with primary acquired NLDO who require DCR, male gender and presence of sac distension are more frequently associated with dacryoliths. Partial NLDO and history of cigarette smoking may also be relative risk factors for dacryolith formation. These observations may be helpful in the evaluation and surgical planning for patients with lacrimal obstruction.

Dacryocystorhinostomy↗
PubMed2001

Giant cell angiofibroma of the nasolacrimal duct.

PURPOSE: To describe clinical and histologic features of the first case, to our knowledge, of giant cell angiofibroma located in the nasolacrimal duct region in a 28-year-old woman. METHODS: Interventional case report. A left nasolacrimal duct tumor was excised en bloc by lateral rhinotomy. Histopathologic examination was performed with the use of light microscopy. Immunohistochemical staining included S-100 protein, muscle-specific actin, desmin, myoglobin, vimentin, and CD34. RESULTS: The lesion was characterized by haphazardly arranged oval to spindled cells, a myxoid and collagenous stroma, multinucleated giant cells, prominent blood vessels, and pseudovascular spaces. Tumor cells were strongly positive for vimentin and CD34 and were negative for other antigens. After excision, there has been no recurrence over 4 years of follow-up. CONCLUSIONS: Originally described as an orbital tumor, giant cell angiofibroma also may occur in the nasolacrimal duct and lacrimal sac region. This mesenchymal neoplasm should be included in the differential diagnosis of lacrimal drainage system tumors.

Adult↗
PubMed2000

Frequency of the common canaliculus: a radiological study.

BACKGROUND: It is frequently stated in the literature that there is a common canaliculus (CC) in the lacrimal drainage system in about 90% of individuals; in the remaining 10%, the upper and lower canaliculi enter the lacrimal sac separately. To our knowledge, there is no quantitative study supporting this assumption. OBJECTIVE: To investigate the frequency of the CC and other anatomical types connecting the upper and lower canaliculi to the lacrimal sac. MATERIALS AND METHODS: We presumed that there might be 3 different types of anatomical connection between the lacrimal sac and the canaliculi. Digital subtraction macrodacryocystograms obtained from 281 patients with obstructive epiphora were reviewed, and those of 247 patients were included in the study. These patients were grouped according to the anatomical types. RESULTS: Dacryocystographies were performed on 153 patients unilaterally and 94 bilaterally. We observed a CC in 321 (94.1%) of 341 lacrimal drainage systems. In 13 lacrimal drainage systems (3.8%), the CC was absent, but the upper and lower canaliculi joined at the wall of the lacrimal sac. In only 7 lacrimal drainage systems (2.0%) did the upper and lower canaliculi enter the sac separately. In 2 patients with bilateral dacryocystograms, a CC was seen on one side but not on the other side. CONCLUSIONS: The frequency of separate drainage of the upper and lower canaliculi into the lacrimal sac is only 2.0%. The CC might not be present bilaterally in all individuals.

Adolescent↗
PubMed1999

An unusual case: bilateral orbital varices.

PURPOSE: To present a rare case of bilateral orbital varices. METHODS: An 18-year-old man showing bilateral orbital masses on magnetic resonance (MR) imaging was examined with color Doppler ultrasonography (US), computed tomography (CT) and digital subtraction venography. RESULTS: The presenting symptoms of the patient were pain and fullness in both orbits induced by bending forward. Ocular examination was normal with the exception of a two millimeter proptosis of both eyes during Valsalva maneuver. MR imaging demonstrated bilateral retrobulbar masses, but was not diagnostic. The comparison of CT images obtained before and after Valsalva maneuver revealed the diagnosis of orbital varices. Color Doppler US and orbital venography demonstrated a large venous connection between the lesions and systemic circulation. CONCLUSION: Clinical presentation of orbital varices is unusual. Different radiological methods may be necessary for the confirmation of the diagnosis and demonstration of the anatomic and the dynamic features of the lesions.

Adolescent↗
PubMed1999

Treatment of obstructive epiphora in adults by balloon dacryocystoplasty.

AIMS: To determine the efficacy of dacryocystoplasty with balloon dilatation in the treatment of complete and partial obstruction of the lacrimal drainage system. METHODS: The procedure was performed on 26 patients with epiphora due to complete (n=16) or partial (n=10) obstruction of the lacrimal drainage system. A flexible tipped guide wire was introduced through the superior canaliculus into the inferior meatus and manipulated out of the nasal cavity. A 3 mm balloon was then introduced in a retrograde direction over the guide wire and dilated at the obstruction site. RESULTS: The procedure was technically successful in all patients with partial obstruction, but unsuccessful in four of 16 cases with complete obstruction. Reobstruction occurred in eight of 12 patients with complete obstruction, and in five of 10 patients with partial obstruction. The overall success rate was 25% for complete and 50% for partial obstructions. The mean follow up was 14 months (8-37 months). CONCLUSION: Although the balloon dacryocystoplasty is a simple and minimally invasive technique, the outcome from our study indicates that it is not advisable for treatment of complete obstruction of the lacrimal drainage system. Balloon dilatation may prove suitable for the treatment of patients with partial obstruction below the level of the lacrimal sac, especially in those who are poor candidates for surgery, or who do not wish to undertake dacryocystorhinostomy. Even in the partial obstruction group the success rate was only 50%, so that further modification to the technique and controlled studies are likely to be required before it could be recommended for general use.

Adolescent↗
PubMed1999

Radiation therapy in exudative age-related macular degeneration.

It has been suggested that ionizing radiation at doses relatively safe to the optic nerve and retina exert an inhibitory and occlusive effect on the endothelial proliferation of choroidal neovascularization (CNV) associated with age-related macular degeneration (AMD). The encouraging results of early studies in preservation or improvement of visual acuity and regression of the CNV gave rise to many clinical trials in different centers. Disparate radiation doses, dose fractions, type and rate of radiation administration have been used to determine the efficacy of radiotherapy in AMD. Conflicting treatment responses have been reported by different centers. Some studies provided evidence of beneficial treatment outcome in AMD, and others could not show any efficacy of ionizing radiation in the visual and morphological evolution of the disease. Data from the literature and our experience indicate that radiotherapy can be effective in regressing the leakage of the CNV in AMD. However, despite treatment visual deterioration continues and new CNV lesions develop. The observation of morphological progression in the disease process might be related to an unfavorable effect of radiation on the pathogenesis of AMD.

Choroidal Neovascularization↗
PubMedDate not supplied

Volvulated paraoesophageal gastric herniation with perforation into bursa omentalis: report of a case.

Although paraoesophageal hernias remain 30% asymptomatic, when diagnosed they have to be operated because of their fatal complications such as ischaemia, bleeding and perforation. The mortality rate increases to twenty times in emergency cases when it is compared with elective ones. Site of gastric perforation may be directed towards bursa omentalis as well as to peritoneal cavity. A case of a volvulated paraoesophageal gastric herniation ruptured to bursa omentalis is discussed with the review of the literature.

Fatal Outcome↗