Ali Demirci

Pituitary dimensions and volume measurements in pregnancy and post partum : MR assessment

Purpose: Our purpose was to clarify and further characterize the changes in height, length, width, volume, and shape in the normal pituitary gland and in width in the infundibulum during pregnancy and the first 6 months post partum. Material and Methods: Cranial MR imaging was performed in 78 women who were pregnant in the second or third trimester or who were post partum, and in 18 age-matched control subjects who were not pregnant. Volume measurements were performed in 2 ways; volume 1=1/2xheightxlengthxwidth; and volume 2=area (measured by trackball)xslice thickness Results: Gland volume, height, width, length, and convexity, and infundibular width increased during pregnancy. the highest values were seen during the 3 days immediately post partum. When compared with volunteers, volumes 1 and 2 showed the largest increase (120%) among the parameters. Gland height showed the best correlation (r=0.94, p>0.00001) with gestational age. the mean height of the gland was 8.76 mm in the third trimester. None of the pregnant women had a gland height of above 10 mm during pregnancy. Only 2 subjects had gland heights of 10.04 and 10.2 mm during the 0–3 days post partum. After this first post-partum period of 3 days, the gland size, shape, and volume and the infundibular width returned to normal within 6 months Conclusion: the pituitary gland enlarges in three dimensions throughout pregnancy. During pregnancy, the volume of the gland shows the highest percentage of increase compared to its length, height, and width. the maximum height of the gland does not exceed 10 mm during pregnancy but it may exceed 10 mm during the 3 days immediately post partum.

Ocular hemodynamics in pseudoexfoliation syndrome and pseudoexfoliation glaucoma

OBJECTIVE To evaluate orbital blood flow velocities by using color Doppler imaging in patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma. DESIGN Prospective, comparative case series. PARTICIPANTS Twenty-eight patients with pseudoexfoliation syndrome (n = 14) or pseudoexfoliation glaucoma (n = 14) and 14 healthy control participants were included. INTERVENTION Color Doppler imaging was used with a 7.5-MHz probe. Evaluation of the ophthalmic, central retinal, short posterior nasal, and temporal ciliary arteries was performed, and peak systolic and end diastolic flow velocities were measured. Resistive indices were calculated. RESULTS When compared with the control participants, patients with pseudoexfoliation syndrome showed statistically significant decreases in the mean peak systolic velocity of the central retinal artery (11.21 +/- 2.19 cm/second; P < 0.05), and end diastolic velocities of the central retinal artery (3.00 +/- 1.03 cm/second; P < 0.005), and short posterior temporal ciliary arteries (3.50 +/- 1.74 cm/second; P < 0.005), whereas mean resistive indices of the ophthalmic artery (0.75 +/- 0.06 cm/second; P < 0.005) and central retinal artery were found to have increased (0.70 +/- 0.05 cm/second; P < 0.01). Patients with pseudoexfoliation glaucoma, when compared with the control participants, showed statistically significant decreases in the mean peak systolic and end diastolic velocities and increased mean resistive indices in all vessels measured (P < 0.05). Compared with the patients with pseudoexfoliation syndrome, patients with pseudoexfoliation glaucoma showed statistically significant decreases in the mean peak systolic velocities of the ophthalmic artery (30.07 +/- 4.00 cm/second; P < 0.05) and short posterior nasal ciliary arteries (2.35 +/- 0.09 cm/second; P < 0.05), and in the mean end diastolic velocities of the ophthalmic artery (6.28 +/- 2.12 cm/second; P < 0.05), and short posterior nasal ciliary arteries (2.35 +/- 0.09 cm/second; P < 0.05). The differences in the mean resistive indices were not statistically significant between the patients with pseudoexfoliation syndrome and the ones with pseudoexfoliation glaucoma. CONCLUSIONS The findings suggest that hemodynamic parameters in the retrobulbar vessels were altered in patients with pseudoexfoliation syndrome and pseudoexfoliation glaucoma; however, these alterations were more prominent in the latter group.

The Effects of Menopause and Hormone Replacement Therapy on Quality and Quantity of Tear, Intraocular Pressure and Ocular Blood Flow

Objective: To evaluate the effects of menopause and hormone replacement therapy (HRT) on the quality and amount of tear, intraocular pressure (IOP) and retrobulbar blood flow velocities. Patients and Methods: Twenty women aged between 40 and 50 years, free of ocular and systemic diseases and planning to receive HRT were recruited as the study group. Twenty-four healthy, age-matched but still menstruating women were enrolled as controls. On the first day of study basal and reflex Schirmer test, tear break-up time and IOP measurements (at 08.00, 12.00 and 16.00 h) were performed for all groups. On the second day of the study, the peak systolic velocity (PSV), end diastolic velocity (EDV) and resistivity index (RI) of the ophthalmic (OA), central retinal (CRA), nasal (NSPCA) and temporal short posterior ciliary (TSPCA) arteries were determined by color Doppler imaging. The menopausal group received HRT for 2 months, when all measurements were repeated for the 15 women who had received HRT on a daily basis. Results: The quality and amount of tear decreased (p < 0.01), IOP (p < 0.01) and RI of the CRA, TPCA and NPCA (p < 0.05) increased in postmenopausal women compared with the control group. After 2 months of HRT, the quality and amount of tear had increased (p < 0.001) and the IOP had decreased (p < 0.001). The PSV of the CRA and TSPCA had decreased (p < 0.05), as had the RI in the CRA (p < 0.001), NSPCA and TSPCA (p < 0.05). Conclusion: We conclude that age-induced changes on quality and amount of tear, IOP and retrobulbar blood flow are intensified by the menopause and that it may be possible to decrease the menopausal effects on these parameters by HRT.

Diffusion-Weighted Imaging in the Differential Diagnosis of Cystic Lesions of the Pancreas

OBJECTIVE The purpose of our study was to evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of pancreatic cysts. SUBJECTS AND METHODS Forty-two cysts (16 simple cysts, seven pseudocysts, five abscesses, three hydatid cysts, two serous cystadenomas, three mucinous cystadenomas, two mucinous cystadenocarcinomas, four cystic degenerated adenocarcinomas) were included in this prospective study. Single-shot spin-echo echo-planar DWI was performed with three b factors (0, 500, and 1,000 s/mm(2)), and apparent diffusion coefficients (ADCs) were calculated. On DWI, the signal intensity of the cysts was visually compared with the signal intensity of the pancreas parenchyma. For the quantitative evaluation, cyst-to-pancreas signal intensity ratios, ADC of the lesions, and cyst-to-pancreas ADC ratios were compared. RESULTS On visual evaluation, all cystic lesions were hyperintense on DWI with b factors of 0 and 500 s/mm(2). On DWI with a b factor of 1,000 s/mm(2), all abscesses and hydatid and neoplastic cysts were hyperintense, whereas most of the simple and pseudocysts were isointense. Quantitatively, with b factors of 0 and 500 s/mm(2), no statistical significance was achieved. With a b factor of 1,000 s/mm(2), the cyst-to-pancreas signal intensity ratios of the abscesses and hydatid and neoplastic cysts were significantly higher than those of the simple cysts and pseudocysts. Setting the cutoff value of signal intensity ratio at 1.9, the cyst-to-pancreas signal intensity ratio had a sensitivity of 70% and a specificity of 90% for differentiating abscesses, hydatid cysts, and neoplastic cysts from simple cysts and pseudocysts. The ADC and the ADC ratios of the abscesses, hydatid cysts, and neoplastic cysts were significantly lower than those of the simple cysts and pseudocysts. CONCLUSION DWI may help in the differential diagnosis of pancreatic cysts.

Diffusion-Weighted Imaging in the Differential Diagnosis of Simple and Hydatid Cysts of the Liver

OBJECTIVE The purpose of our study was to evaluate the value of diffusion-weighted imaging (DWI) in the differential diagnosis of simple and hydatid cysts of the liver, particularly in the completely liquid type of hydatid cyst. SUBJECTS AND METHODS Eighty-two cysts (43 simple cysts, 39 hydatid cysts) were included in this prospective study. DWI was performed using a breath-hold single-shot echo-planar spin-echo sequence, and apparent diffusion coefficients (ADCs) were calculated. On DW trace images, the signal intensity of cysts was visually compared with the signal intensity of the liver using a 3-point scale: 0, isointense; 1, moderately hyperintense; and 2, significantly hyperintense. Quantitatively, signal intensity of the cysts, cyst-to-liver signal intensity ratios, ADC of the cysts, and cyst-to-liver ADC ratios were compared between the groups. The statistical significance was determined using the Mann-Whitney U test. RESULTS On trace DWI (b = 1,000 s/mm2), most hydatid cysts (37/39, 95%) were hyperintense, whereas most simple cysts (40/43, 93%) were isointense with the liver. Three simple cysts (7%) were moderately hyperintense and two hydatid cysts (5%) were isointense. Quantitatively, both the signal intensity and cyst-to-liver signal intensity ratio of the hydatid cysts were significantly higher than those for simple cysts (p < 0.001). The cutoff value at 1.5 yielded a sensitivity of 77%, a specificity of 86%, and positive predictive value of 83% for the cyst-to-liver signal intensity ratio. The ADC and cyst-to-liver ADC ratio of the hydatid cysts were significantly lower than those of simple cysts (p < 0.005). For the completely liquid type in particular, we observed statistically significant differences in signal intensity, signal intensity ratio, ADC, and ADC ratios from those of simple cysts (p < 0.005). With a cutoff value of 1.5, signal intensity ratio had a sensitivity of 81%, specificity of 86%, and positive predictive value of 74%. CONCLUSION DWI may help in the differential diagnosis of hydatid and simple cysts of the liver.

Magnetic Resonance Imaging of the Brain in Patients with Pseudoexfoliation Syndrome and Glaucoma

Purpose: To evaluate ischemic changes in brain magnetic resonance images in patients with pseudoexfoliation syndrome (PXS) and pseudoexfoliation glaucoma (PXG) and compare them with age- and sex-matched control subjects. Methods: This case-control study involved 16 consecutive patients with PXS, 21 patients with PXG and 18 healthy age- and sex-matched control subjects. Each subject underwent a comprehensive ophthalmological examination. In all participants, an axial T1-, T2- and proton-density-weighted and coronal cerebral 1.5-tesla magnetic resonance imaging (MRI) scan was made. White matter hyperintensities (WMH) were considered present if these were hyperintense on both proton-density- and T2-weighted images and not hypointense on T1-weighted images. White matter lesions were classified into two parts as the subcortical and periventricular regions. We used a validated rating scale of subcortical WMH: 0 = absent, 1 = punctuate foci, 2 = beginning confluence of foci and 3 = large confluent areas. Periventricular white matter lesions were classified on a scale of 0 (no white matter lesions), 1 (pencil-thin periventricular lining), 2 (thick lining) or 3 (large confluent white matter lesions). Results: The proportions of persons with WMH were 93.7% for patients with PXS, 95.2% for patients with PXG and 55.5% for control subjects. The numbers of white matter lesions in patients with PXS and PXG were significantly greater than in the control subjects (p < 0.05). White matter lesions at subcortical locations in patients with PXG were significantly more frequent than in the control subjects (80.9 vs. 33.3%; p < 0.05). The proportion of patients with subcortical WMH was 56.2% in PXS; no significant difference was found in subcortical WMH between PXS and controls. The proportions of patients with periventricular WMH were 93% in PXS, 90.4% in PXG and 44.4% in controls. White matter lesions at periventricular locations in patients with PXG and PXS were significantly more frequent than in the control subjects (p < 0.05). The difference between the pseudoexfoliation groups and controls with regard to the size of periventricular and subcortical white matter lesions was statically significant (p < 0.05). When patients with PXS were compared with PXG patients, there was no statistically significant difference in the number, size and scale of white matter lesions. Conclusion: We found a significantly higher prevalence of MRI-defined WMH in patients with a clinical diagnosis of pseudoexfoliation with or without glaucoma versus control subjects. We think that the findings in this study may shed light on a possible link between ischemic brain lesions and pseudoexfoliation, which is not related with the presence of glaucomatous optic neuropathy. Further investigations are required to resolve the underlying associations.

Comparison of Blood Flow Velocities of the Extraocular Vessels in Patients with Pseudoexfoliation or Primary Open-Angle Glaucoma

Purpose: To evaluate orbital blood flow velocities in patients with pseudoexfoliation glaucoma (PXG) or primary open-angle glaucoma (POAG). Methods: Blood flow velocities in the ophthalmic, central retinal, and posterior ciliary arteries were evaluated by color Doppler imaging in 26 patients with PXG, 28 patients with POAG and 30 age-matched normal control subjects. The results were compared. Results: Compared to the control subjects, patients with PXG showed statistically significant decreases in the mean peak systolic and end-diastolic velocities and increased mean resistive indices in all vessels except for the ophthalmic artery mean peak systolic velocity (p < 0.05). Patients with POAG, when compared to the control subjects, showed statistically significant decreases in the mean end-diastolic velocities and increased mean resistive indices in all vessels measured (p < 0.05). No statistically significant differences were found in the mean blood flow parameters between POAG and PXG. Conclusion: Blood flow velocities of the retrobulbar vessels are decreased in patients with PXG. Reduced blood flow velocities may be secondary as well as contributory to exfoliative glaucomatous damage. Although there was no significant difference in the mean blood flow parameters between POAG and PXG, alterations of retrobulbar vessels might be associated with different pathogenic mechanisms of PXG.

Differentiation of malignant and benign lung lesions with diffusion-weighted MR imaging

Differentiation of malignant and benign lung lesions with diffusion-weighted MR imaging Background. The aim of the study was to evaluate the role of diffusion-weighted magnetic resonance imaging in the differential diagnosis of lung lesions. Patients and methods. Sixty-seven patients with lung lesions (48 malignant, 19 benign) were included in this prospective study. Signal intensities (SIs) were measured in diffusion-weighted MR images that were obtained with b=0, 500 and 1000 s/mm2 values. Apparent diffusion coefficient (ADC) maps were calculated by using images with b=0 and 1000 s/mm2 values. The statistical significance was determined using the Student-t test. Results. The SIs of malignant lesions were significantly higher than those of benign lesions (p<0.004 for b=0 s/mm2 and p<0.000 for the other b values). Using b=500 s/mm2, SI≥391 indicated a malignant lesion with a sensitivity of 95%, specificity of 73% and positive predictive value of 87%. Using b=1000 s/mm2, SI≥277 indicated a malignant lesion with a sensitivity of 93%, specificity of 69% and positive predictive value of 85%. There was no significant difference between malignant and benign lesions regarding ADC values (p=0.675). There was no significant difference in SIs or ADC values between small cell carcinoma and non-small cell carcinoma. When comparing undifferentiated with well- partially differentiated cancers, SIs were higher with all b values, but the difference was statistically significant only with b=1000 s/mm2 (p<0.04). Conclusions. Diffusion-weighteted MR trace image SI is useful for the differentiation of malignant versus benign lung lesions.

Silent cerebral infarction in chronic heart failure: Ischemic and nonischemic dilated cardiomyopathy

Objectives Patients with dilated cardiomyopathy (DCM) may have a high incidence of clinically asymptomatic silent cerebral infarction (SCI). Prevalence of SCI and its risk factors may differ between ischemic and nonischemic DCM. The purpose of this study was to evaluate prevalence and related parameters of silent cerebral infarction in patients with ischemic and nonischemic DCM. Methods Patients with ischemic and nonischemic DCM (53 male, 19 female, aged 62 ± 12 years) were included in the study. Etiology of DCM was ischemic in 46 and nonischemic in 26 patients. Fifty-six age- and gender-matched healthy volunteers served as a control group for comparison of SCI prevalence. Results Prevalence of SCI was 39%, 27%, and 3.6% in ischemic, nonischemic DCM, and control group, respectively (ischemic DCM vs control group, p < 0.001, nonischemic DCM vs control group, p = 002). In patients with nonischemic DCM, the mean age of the subjects with SCI was significantly higher than that of subjects without lesions (67 ± 5 years vs 53 ± 13, p < 0.001), whereas in ischemic DCM NHYA Functional Class was statistically higher in patients with SCI than without SCI (p = 0.03). In both groups, patients with SCI had lower systolic functions than patients with normal MRI findings. In multivariable logistic regression analysis, restrictive type of diastolic filling pattern was found as an independent factor for SCI occurrence on the whole patient population (OR: 16.5, 95% CI: 4.4–61.8, p < 0.001). Conclusion SCI is common in patients with both ischemic and nonischemic DCM. In univariate analysis, both groups have similar systolic and diastolic characteristics in the occurrence of SCI. Logistic regression analysis revealed that restrictive diastolic filling pattern is an independent risk factor in the occurrence of SCI for the whole patient population.

Apparent Diffusion Coefficient and Cerebrospinal Fluid Flow Measurements in Patients With Hydrocephalus

Objective: To evaluate the efficacy of diffusion magnetic resonance imaging and compare with cerebrospinal fluid (CSF) flow imaging in patients with hydrocephalus before and after treatment. Methods: Twenty patients with hydrocephalus (group 1, pediatric, with primary aqueductal stenosis, n = 10; group 2, adult, with normal-pressure hydrocephalus, n = 10) and 20 age-matched healthy subjects that served as controls were examined. Cerebrospinal fluid flow velocity interval was calculated as the mean absolute values of the peak craniocaudal velocity and caudocranial velocity on CSF flow measurements. On diffusion magnetic resonance imaging, apparent diffusion coefficient (ADC) values from 8 regions were evaluated. Results: The decrease in ADC values after treatment was significant in both groups (P < 0.001 for both). Preoperative mean CSF flow velocity interval value was significantly lower in group 1 and significantly higher than postoperative and control group values in group 2 (P < 0.001 for all). Conclusion: The ADC values increase in hydrocephalus and decrease significantly after treatment. Preoperative ADC value may serve as baseline, and the change in ADC may be an indicator of response to treatment and CSF flow measurements.