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Öğe Effect of region of interest on interobserver variance in apparent diffusion coefficient measures(Amer Soc Neuroradiology, 2004) Bilgili, Y; Unal, BBACKGROUND AND PURPOSE: Apparent diffusion coefficient (ADC) values derived from diffusion-weighted MR imaging are useful measurements for assessment of cellular alterations in pathologic conditions of the brain. In this study, two radiologists independently quantitated ADCs and region-of interest sizes in prespecified locations of human brain to test interobserver ADC variance and the effect of varying ROI sizes on ADC differences. METHODS: Twenty-seven patients with normal MR findings underwent diffusion-weighted imaging (b value = 1000 s/mm(2)) on a 1.5-T system. Two radiologists independently placed two ROI areas of 22 +/- 5 mm(2) and 62 +/- 6 mm(2) (former area inside the latter area) at different sites of the brain (centrum semiovale, frontal white matter, nucleus caudatus, putamen, thalamus, substantia nigra, red nucleus, and pons) from trace images. Differences in ADC measurement obtained from each region of the brain for each radiologist and the size of each ROI were compared statistically. RESULTS: Mean ADC of prespecified areas of brain ranged between 0.673 and 0.818 mm(2)/s x 10(-3). Interobserver variance was significant in some of the specified areas (centrum semiovale, frontal white matter, pons, substantia nigra, and red nucleus). Varying ROI sizes at the pons, substantia nigra, and red nucleus yielded statistically different ADC values. CONCLUSION. ADC values are found to be unreliable for use in assessing brain disease in some specified areas of the brain owing to interobserver variance and different ROI sizes.Öğe The effects of cyclopentolate on intraocular pressure and retrobulbar hemodynamics in patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma(Wichtig Editore, 2004) Taner, P; Unal, B; Demirbas, E; Ergin, APURPOSE. To evaluate the changes of intraocular pressure (IOP) and retrobulbar hemodynamics after cyclopentolate administration in patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma. METHODS. Eighteen patients with pseudoexfoliation syndrome and 18 patients with pseudoexfoliation glaucoma were enrolled in the study. After baseline measurements of IOP, the peak systolic velocity (PSV), end-diastolic velocity (EDV), and resistivity index (RI) of the ophthalmic, central retinal, and posterior ciliary arteries were investigated by color Doppler imaging. Then, 1% cyclopentolate was instilled in one eye of each subject. After 45 minutes of instillation of the cyclopentolate, the measurements of IOP and retrobulbar blood flow velocities were repeated. The results were compared with those of 20 age-matched normal subjects. RESULTS. Neither IOP nor retrobulbar blood flow velocities changed significantly in control subjects after cyclopentolate administration. IOP increased significantly after cyclopentolate instillation in pseudo exfoliation syndrome (p=0.004). Retrobulbar blood velocities did not change significantly after the cyclopentolate in this group. In pseudoexfoliation glaucoma group, it was observed that basal mean IOP showed a statistically significant increase after cyclopentolate drop (p=0.002). Although blood flow velocities of ophthalmic artery did not change significantly, PSV and EDV of the central retinal and posterior ciliary arteries decreased significantly (p<0.05) and RI of the posterior ciliary artery increased significantly (p=0.01) after cyclopentolate instillation. CONCLUSIONS. On the basis of our findings, pseudoexfoliation appears to be a predictive factor for an IOP rise after cyclopentolate. In pseudoexfoliation glaucoma patients, an increase of IOP after cyclopentolate could lead to a decreased retrobulbar blood flow. IOP must be rechecked after cyclopentolate administration in these patients to avoid further damage to the ganglion cells.Öğe Evaluation of differences between observers and automatic-manual measurements in calculation of Doppler parameters(Wiley, 2004) Unal, B; Bagcier, S; Simsir, I; Bilgili, Y; Kara, SObjective. We aimed to search for differences between observers and automatic and manual measurements in calculations of Doppler parameters. Methods. The middle cerebral artery (MCA), central retinal artery, ophthalmic artery (OA), common carotid artery (CCA), vertebral artery (VA), popliteal artery (PA), interlobar renal artery (IRA), and arcuate renal artery (ARA) were evaluated in 20 healthy subjects bilaterally Peak systolic velocity (PSV), end-diastolic velocity (EDV), time-averaged maximum velocity (TAMAX), resistive index (RI), and pulsatility index (Pi) were measured from the same spectrum manually by 3 observers and automatically. Results of 4 measurements were compared by analysis of variance and Pearson tests. Results. The comparison of the 4 measurements revealed significant differences for most parameters except TAMAX of the OA, VA, and ARA and PSV EDV and PI of the PA. An automatic calculator yielded lower PSV, RI, and PI values (except the MCA and PA) and higher EDV values compared with manual measurements. The magnitudes of difference were in the range of 1% to 16% for velocities and 4% to 14% for RI and PI. The means of difference were 3.185 cm/s for PSV of the CCA and 0.054 for RI of the IRA. Correlation was high for PSV, EDV, and TAMAX in all arteries (except TAMAX of PA) and relatively low for PI and RI in most of the arteries. Conclusions. Although our study was performed on healthy subjects, our results showed that, in most cases, readers and the automatic approach disagreed on evaluation of Doppler parameters. This may be important in preventing false diagnoses in cases with Doppler values close to upper limits and may necessitate establishment of new limits for each method.Öğe Late-onset ureteric urinoma with intermittent jet flow as a complication of ureterolithotomy(John Wiley & Sons Inc, 2004) Unal, B; Basar, H; Bilgili, MYK; Basar, M; Batislam, E; Erdal, HH; Kara, SWe present the case of a late-onset urinoma in a 47-year-old man with a history of right ureterolithotomy performed 6 months previously, following 2 unsuccessful attempts at extracorporeal shock wave lithotripsy. The ipsilateral kidney was nonfunctional and hydronephrotic. The urinoma did not show enhancement on contrast-enhanced CT and intravenous pyelography. Sonography revealed turbulence in the urinoma and jet flow from the ureter. Lab studies of fluid obtained by percutaneous puncture and aspiration yielded misleading findings for urine and revealed the presence of hemosiderin-laden macrophages. The urinoma was surgically resected and ureteroneocystostomy was performed. (C) 2004 Wiley Periodicals, Inc.Öğe Short-term effect of latanoprost on ocular circulation in ocular hypertension(Blackwell Publishing Asia, 2004) Akarsu, C; Bilgili, YK; Taner, P; Unal, B; Ergin, APurpose: To determine the short-term effects of latanoprost on retrobulbar circulation in ocular hypertension. Methods: Forty-six eyes of 23 consecutive bilateral ocular hypertensive patients with an intraocular pressure (IOP) of greater than 22 mmHg were evaluated in a prospective controlled study. All subjects received a single drop of latanoprost 0.005% in one eye and placebo in the fellow control eye. Systemic circulatory parameters, intraocular pressure, blood flow velocities, and resistance indices of the ophthalmic, short posterior ciliary and central retinal arteries were measured using colour Doppler imaging at baseline and 2 h and 8 h after dosing, Results: Latanoprost lowered IOP significantly after 2 h and 8 h (P < 0.01). The mean IOP reduction was 6.7 mmHg 8 h after dosing. At baseline, there were no statistically significant differences in any retrobulbar vessels of eyes that received a single drop of latanoprost when compared with the eyes that received placebo (P > 0.05). Comparisons with baseline and latanoprost conditions revealed that latanoprost did not alter the blood flow velocities and resistance indices in the ophthalmic (P > 0.05), posterior ciliary (P > 0.05) and central retinal (P > 0.05) arteries 2 h and 8 h after dosing. The systolic and diastolic blood pressures (P = 0.74, P = 0.29, respectively) and pulse rate (P = 0.68) remained unchanged over the 8-h period. Conclusions: This study found that a single drop of latanoprost significantly reduces intraocular pressure 8 h after dosing. However, it does not have any short-term effects on the retrobulbar haemodynamics in ocular hypertensive eyes.
