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Öğe Cerebral diffusional changes in the early phase of anthrax: Is cutaneous anthrax only limited to skin?(W B Saunders Co Ltd, 2006) Karakas, HM; Bayindir, Y; Firat, AK; Yagmur, C; Alkan, A; Kayabas, UObjectives. Characteristics of cerebral diffusion in the acute period of the anthrax infection were investigated to understand the pathophysiology of the disease. Methods. Six cutaneous anthrax patients (mean age: 33.3, SD: 18.1) and six healthy control subjects (mean age: 33.7, SS: 19.6) were examined at the acute phase of the infection with diffusion weighted imaging on 1.5 T scanner. ADC values were measured from five different cerebral locations. T-tests, Logistic regression and ROC curves were used. Results. Anthrax patients were significantly different than controls regarding cortical ADC values (p < 0.05). Logistic regression model accurately classified five out of the six anthrax cases (83.3%). A cut-off value of 574 mm(2)/s x 10(-3) was found by using ROC curve coordinates. A sensitivity of 100% and a specificity of 67% were attained by means of this value. Conclusions. This study shows the existence of cerebral parenchymal. changes at microstructural. level in cutaneous anthrax without neurological findings. These changes are possibly related to the components of the toxin. Our results support the general but unproven opinion that anthrax treatment does not change the existence and the effects of the toxin. Pathophysiological. mechanisms towards classification should therefore be reviewed. (c) 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved.Öğe The comparison of femoral curves and curves of contemporary intramedullary nails(Springer, 2005) Harma, A; Germen, B; Karakas, HM; Elmali, N; Inan, MThe aim of this study was to evaluate both the cortical and the medullary anterior bowing of the femur, and to compare these measurements with current intramedullary nails to assess the adequacy of their design. Methods: Lateral digital radiographic views of left femurs of 104 normal subjects (18-68 years old) were obtained. Radii of cortical and medullary curvatures of femurs were calculated using these images. The values obtained were compared to the radius of curvatures of ten different intramedullary nails. Results: Medullary bowing was between 114 and 1,389 mm (mean: 722 mm, SD: 230 mm) and the cortical bowing was between 109 and 1,666 mm (mean: 770 mm, SD: 267 mm). For males, these values were 114-1,389 mm (mean: 722 mm, SD: 230 mm) and 109-1,666 mm (mean: 770 mm, SD: 267 mm), respectively. For females, they were 114-1,389 mm (mean: 722 mm, SD: 230 mm) and 109-1,666 mm (mean: 770 mm, SD: 267 mm), respectively. The differences between genders were not significant. Cortical and medullar bowing was strongly correlated with age (r=-0.269, p < 0.006 and r=-0.234, p < 0.017, respectively). These significances were produced by females only. Radii of curvatures of intramedullary nails ranged between 150 and 300 cm and were higher than the mean cortical (77 cm) and medullary (72.2 cm) bowings. Conclusion: The difference between the curves of femur and the contemporary femoral nails implicates the inadequacy of the design of such nails for the Caucasian race living in Anatolia. Therefore, such nails should be revised accordingly to prevent the above-mentioned complications.Öğe Dynamic contrast enhanced MRI in the differential diagnosis of soft tissue tumors(Elsevier Sci Ireland Ltd, 2005) Tuncbilek, N; Karakas, HM; Okten, OOPurpose: The value of the dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) in differentiating benign and malignant soft tissue tumors was investigated. Materials and methods: Turbo FLASH DCE-MRI was performed on 22 subjects (2-74 years) with soft tissue tumors. Enhancement in the first min (E-max/1), second min (E-max/2) and maximum peak enhancement (E-max), and steepest slope were calculated. Discriminant analyses were performed to reveal parametric differences of benign and malignant lesions. Results: Diagnosis of benign (N = 10) tumors were hemangioma (n = 3), neurogenic tumor (n 3) lipoma (n = 2), giant cell tumor (n = 1) and desmoid (n = 1), whereas malignant lesions (N = 12) were classified as liposarcoma (n 5), malignant fibrous histiocytoma (n = 5) and synovial sarcoma (n = 2). For malignant lesions E-max/1 was 65-198%, E-max/2 was 65-145%, E-max was 78-198%, and steepest slope was 1.45-4.06. For benign lesions these values were 4-98%, 5-105%, 7-125% and 0.67-2.57, respectively. To determine the relation between the variables analysed, Pearson correlation coefficients were calculated. E-max was found to be highly correlated with other variables (rxy > 0.86, P < 0.0001). Consequently, this variable was excluded from the discriminant analysis. In order to determine discrimination of malignant and benign tumors using E-max/1, E-max/2, and steepest slope of the enhancement curve logistic regression was applied to the above mentioned data. When combined these parameters had a 95.5% of overall accuracy in classifying benign and malignant lesions (P = 0.004). Conclusion: DCE-MRI parameters that thought to be the surrogate markers of tumoral microcirculation and tissue perfusion provides a specific preoperative diagnosis. Dynamic imaging parameters are therefore advocated for monitoring the effect of chemotherapy in soft tissue tumors. (c) 2004 Elsevier Ireland Ltd. All rights reserved.Öğe Dynamic magnetic resonance imaging in determining histopathological prognostic factors of invasive breast cancers(Elsevier Ireland Ltd, 2005) Tuncbilek, N; Karakas, HM; Okten, OOObjective: To evaluate the relation between morphological features and enhancement parameters in dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging with histopathological prognostic factors. Materials and methods: Fifty-five patients with surgicopathological diagnosis of breast carcinoma were evaluated with 1.0 T MR scanner as a part of their preoperative diagnostic work-up. Dynamic studies were performed in axial plane using 3D fast low angle shot (FLASH) sequence. Time intensity curves (TICs) were obtained from the regions showing maximal enhancement in subtraction images. The correlations between enhancement parameters and histopathological findings were analyzed using stepwise multiple regression analysis, Student's t-test, chi(2)-tests and Pearson's moment correlation coefficient. Results: Significant correlations were found between the presence of lymph node metastasis and tumor size (P < 0.05) and edge characteristics (P < 0.05). A highly significant correlation was found between histopathological grades and qualitative enhancement patterns (r = 0.403, P < 0.01). Statistically significant differences were found between the groups with and without lymph node metastasis regarding enhancement in the first minute (P < 0.01) and TIC slope (P < 0.05). A significant difference was found between the histopathological grades I and III regarding all quantitative enhancement parameters, whereas no difference was found between the grades I-II, and II-III. Conclusion: DCE-MR imaging helps to predict prognostic factors of breast cancer by revealing morphological features and enhancement parameters of the primary tumor. Additional morphological factors further improve our ability to predict lymphatic metastasis. (C) 2003 Elsevier Ireland Ltd. All rights reserved.Öğe Dynamic MRI in indirect estimation of microvessel density, histologic grade, and prognosis in colorectal adenocarcinomas(Springer-Verlag, 2004) Tuncbilek, N; Karakas, HM; Altaner, SThe relations of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters to microvessel density (MVD), histologic grade, and presence of metastasis were evaluated to establish new prognostic indicators in colorectal cancer (CRC). Fast-low angle shot DCE-MRI parameters (time-intensity curves, TICs; maximal relative enhancement within the first minute, E-max/1; maximal relative enhancement of the entire study, E-max; steepest slope of the contrast enhancement curve; and time to peak enhancement) of 21 CRCs (seven Duke stage B, 12 Duke stage C, and two Duke stage D) were retrospectively evaluated and correlated with corresponding postoperative MVD measurements, histologic grades, and presence of metastasis at 2 years. TICs were classified as type A in nine (43%), type B in seven (33%), and type C in five cases (24%). There was a significant difference between TIC types with regard to MVD (p < 0.05-0.001). Time to peak enhancement, steepest slope of TIC, and E-max/1 were strongly correlated with MVD (r = -0.765, p < 0.01; r = 0.681, p < 0.01; r = 0.634, p < 0.01; respectively). MVD, steepest slope of the enhancement curve, E-max/1, and E-max strongly correlated with histologic grade (r = 0.475, p < 0.05; r = 0.683, p < 0.01; r = 0.687, p < 0.01; r = 0.791, p < 0.01; respectively). There was a significant difference between groups of patients with and without metastasis with regard to histologic grade (p < 0.05) and two of the DCE-MRI parameters (p < 0.005 for E-max/1 and p < 0.05 for time to peak enhancement). Discriminant analysis correctly predicted the metastatic occurrence at 2 years in 90.5% of cases using E-max/1 (p < 0.001). Histologic grade resulted in lower rates of discrimination (66.7%; p < 0.05). DCE-MRI parameters may help in the prediction of MVD and histologic grade in CRC and may be used to predict therapeutic outcome.Öğe General hemispheric assymetry in left-handed subjects: Signal amplitude analysis of bold response in sensory-motor task(Elsevier Science Bv, 2004) Karakas, HM[Abstract Not Available]Öğe Imaging of granulomatous mastitis: assessment of three cases(Churchill Livingstone, 2004) Tuncbilek, N; Karakas, HM; Okten, OOGranulomatous mastitis is a benign, inflammatory breast disease of unknown aetiology, which can mimic breast carcinoma in its clinical manifestations. Imaging features of three cases of granulomatous mastitis mimicking breast carcinoma on both clinical and radiographic examination are presented, with special emphasis on the role of dynamic contrast-enhanced-magnetic resonance mammography in the differential diagnosis. (C) 2004 Elsevier Ltd. All rights reserved.Öğe Learning of serial digits leads to frontal activation in functional magnetic resonance imaging: Clinical implications(Elsevier Science Bv, 2004) Karakas, HM; Karakas, S[Abstract Not Available]Öğe Magnetic resonance spectroscopic comparison of the effects of resveratrol (3,4',5-trihydroxy stilbene) to conjugated equine estrogen, tibolone and raloxifene on ovariectomized rat brains(Elsevier Science Bv, 2005) Celik, O; Erdem, G; Hascalik, S; Karakas, HM; Tamser, MObjective: To investigate the effects of resveratrol on basic cerebral metabolites of in the brains of ovariectomized rats. Materials and methods: Twenty-four bilaterally ovariectomized rats were randomly assigned into six groups With four rats in each group. The groups consisted of sham-operated (control), ovariectomized, resveratrol, conjugated equine estrogen (CEE), tibolone and raloxifene treated rats. Drug administration started at the 5th day following ovariectomy and continued for 35 days. At the end of the entire Course, in vivo single vowel magnetic resonance spectroscopy was performed on whole brains to determine choline, creatine and N-acetyl aspartate (NAA) concentrations. Results: Compared to sham-operated group, ovariectomized group had significantly lower NAA (P < 0.008) but significantly higher choline levels (P < 0.031). Administration of CEE and resveratrol resulted in NAA levels that were similar to those in the sham-operated group, showing that the NAA decrease due to ovariectomy was prevented. Treatment with tibolone and raloxifene resulted in a smaller increase in NAA and the effect failed to reach significance. Administration of resveratrol, CEE, tibolone and raloxifene resulted in choline levels similar to those in sham-operated group, showing that the increase in the ovariectomy group was prevented. Conclusion: Resveratrol causes levels of cerebral metabolites that is similar to conventional hormone replacement agents. This finding may suggest that neuronal function in the postmenopausal state was preserved. More detailed investigation of this issue should be the task of future research. (c) 2004 Elsevier Ireland Ltd. All rights reserved.Öğe MRI in multiple myeloma with orbital and dural invasion(Sage Publications Ltd, 2005) Tuncbilek, N; Karakas, HM; Okten, OO; Vural, OThe case of a 42-year-old woman with aleukemic Bence Jones-type multiple myeloma who developed ocular abnormalities is described. Extramedullary plasmocytomas, either as solitary lesions or as manifestations of multiple myeloma, rarely involve the orbit and dural structures. Early detection of such lesions indicates an aggressive clinical course. In this paper we describe the magnetic resonance imaging findings of ocular and dural myelomatous involvement.Öğe Protective role of melatonin in pinealectomized rat brains: in vivo magnetic resonance spectroscopic analysis(Wiley, 2005) Hascalik, S; Celik, O; Karakas, HM; Parlakpinar, H; Firat, AK; Ozsahin, MThe goal of this study was to investigate the effect of melatonin on basic cerebral metabolites in pinealectomized (Px) rat brains. Twenty-one rats were randomly divided into three groups with seven rats per group. The study groups included sham-operated rats, Px rats and Px rats treated with melatonin. Melatonin administration began at 60 days following pinealectomy and continued for 21 days. At the end of the study, in vivo single voxel magnetic resonance spectroscopy was performed on whole brains to determine choline (Cho), creatine and N-acetyl aspartate (NAA) concentrations. Px rats had significantly lower NAA levels (P < 0.05), and significantly higher Cho levels (P < 0.05) when compared with sham-operated rats. Administration of melatonin had normalized NAA and Cho levels in Px rats. We propose that pinealectomy causes significant changes in cerebral metabolites which are compatible with neural loss. Melatonin administration prevents the disruptive effects of pinealectomy on brain tissue.Öğe Quantitative evaluation of brain involvement in ataxia telangiectasia by diffusion weighted MR imaging(Elsevier Ireland Ltd, 2005) Firat, AK; Karakas, HM; Firat, Y; Yakinci, CObjective: To evaluate the value of diffusion weighted imaging (DWI) in diagnosing ataxia telangiectasia (AT) and to investigate the spatial distribution of cerebral microstructural changes caused by the disease. Methods: Six AT patients (9-13 years) and nine healthy control subjects were examined on 1.5 T scanner. In addition to conventional MR images, DWI were performed with a fat suppressed, multishot spin echo EPI sequence using B values of 0, 500 and 1000 s/mm(2). Mean ADC values were measured from 16 different supra and infratentorial location. The difference between controls and AT patients regarding ADC values, and the accuracy, sensitivity and specificity of them in discrimination were analyzed with t-tests, logistic regression analysis, ANOVA and ROC curves. Results: Conventional images of the controls were normal. In AT patients, the only conventional MR abnormality was cerebellar atrophy. The difference between both groups regarding mean ADC values was not significant for any of the cerebral structures. In contrary to cerebrum, cerebellar mean ADC values of patients and controls were statistically different (p < 0.011-0.0001). Patients and controls were classified with 100% accuracy using ADC values of cerebellar white matter and cortex together (p < 0.016). The cut-off ADC value (0.699 mm(2)/s) for middle cerebellar cortex had produced highest (100%) sensitivity and specificity. There was a difference between superior, middle and inferior cerebellar cortex regarding ADC values (p < 0.026). Superior cerebellar cortex (0.987 +/- 0.1956 mm(2)/s) had higher ADC values than the middle and inferior cerebellar cortex. Conclusion: DWI provides a supplementary and objective imaging finding in AT. This finding is highly accurate in the radiological discrimination of healthy subjects and AT. Our findings also implicate that AT causes a diffuse atrophy and mostly affects superior part of the cortex. (C) 2005 Elsevier Ireland Ltd. All rights reserved.Öğe Sonographic evaluation of the carpal tunnel after provocative exercises(Amer Inst Ultrasound Medicine, 2004) Altinok, MT; Baysal, O; Karakas, HM; Firat, AKObjective. Dynamic carpal tunnel syndrome (CTS) is a subtype of CTS in which symptoms usually subside with rest and return with repetitive motions. In this subgroup, nerve conduction studies, performed at rest, are often inconclusive. In this study, the diagnostic value of provocative sonography was evaluated in patients with dynamic CTS. Methods. Twenty wrists of 13 patients with dynamic CTS and 10 control subjects were investigated with sonography before and immediately after provocative exercises imitating work-related stresses. In addition to conventional indices (palmar displacement, nerve area at the middle level, and swelling ratio before and after exercise), 2 newly formed indices (provocative nerve area ratio and provocative palmar displacement ratio) were investigated. Results. In the pre-exercise period, there were no significant differences between patients and control subjects regarding palmar displacement and the swelling ratio. The difference was significant (P = .035) for the nerve area at the middle level. In the post-exercise period, all parameters were significantly different between patients and control subjects. The nerve area at the middle level and the swelling ratio had higher significance (P < .0001) than palmar displacement (P = .015). The post-exercise swelling ratio had the highest sensitivity (95%) in diagnosing dynamic CTS when a cutoff value of 1.26 was used. The provocative palmar displacement ratio had high sensitivity (80%) and the highest specificity (90%) for a cutoff value of 1.28. Conclusions. Provocative exercises increase sensitivity and specificity and contribute to the sonographic diagnosis of dynamic CTS. This examination should be performed if electrodiagnostic test results are negative.Öğe Synchronous endometrial and cervical tumors in a 26-year-old nullipara: Diagnostic modalities updated(Karger, 2005) Hascalik, S; Celik, O; Erdem, G; Usta, U; Alkan, A; Karakas, HM; Mizrak, BProton magnetic resonance spectroscopy (MRS), performed on conventional magnetic resonance imaging (MRI) scanners, provides useful information at the biochemical level. MRS has been used to measure tissue concentrations of proton-containing compounds such as organic and amino acids, and sugars in living tissues. We have used MRS in a 26-year-old female with suspected cervical and endometrial carcinomas. With the use of the above mentioned technique, biochemical differences in the endometrium and the cervix tissues were detected. The presented case is the first virgin patient in the relevant literature in whom endometrial and cervical carcinoma was detected. Choline (Cho), creatine (Cr), N-acetylaspartate (NAA), lipid and lactate region of the MRS spectrum suggested that the technique could be used as an indicator of metabolic alterations in the cervical and endometrial tumor cells. Copyright (C) 2005 S. Karger AG, Basel.Öğe Ultrasonographic assessment of mild and moderate idiopathic carpal tunnel syndrome(W B Saunders Co Ltd, 2004) Altinok, T; Baysal, O; Karakas, HM; Sigirci, A; Alkan, A; Kayhan, A; Yologlu, SAIM: To investigate the diagnostic value of uttrasonography in mild and moderate idiopathic carpal tunnel syndrome (CTS). MATERIALS AND METHODS: Cross-sectional areas (CSA), flattening ratios at three different levels, swelling ratio, and palmar displacement were analysed in 26 patients (14 with bilateral and 12 with unilateral disease, 40 wrists in total) for the presence and the severity of CTS. Twenty had normal nerve conduction studies (NCS) defined as mild, and 20 of them had abnormal NCS defined as moderate. The control group consisted of 20 healthy participants. RESULTS: All parameters were significantly different between patient and control groups. Palmar displacement, swelling ratio, CSA at all levels and distal flattening ratio had the highest significance (p < 0.0001). The criterion with the highest sensitivity was the swelling ratio greater than or equal to 1.3 (72.5%), followed by the middle CSA >9 mm(2) and the palmar displacement >2.5 mm. All of these criteria had a higher sensitivity in diagnosing moderate cases (85-100%) than diagnosing mild cases (30-55%). There was a significant difference between normal and mild CTS groups regarding palmar displacement, distal flattening ratio, middle CSA and swelling ratio (p < 0.0001 for all) and between normal and moderate groups regarding all parameters (p < 0.01 - 0.0001). When combined middle CSA, palmar displacement and swelling ratio had an overall discriminatory accuracy of 83.8%. CONCLUSION: Additional diagnostic confirmation can be provided by ukrasonography and may be preferred as the initial step instead of etectrophysiotogical. studies. Detection of at least two of the three criteria (median nerve CSA >9 mm(2) at pisiform Level, swelling ratio 1.3, and palmar displacement >2.5 mm) may be helpful for the verification of the diagnosis. (C) 2004 Published by Elsevier Ltd on behalf of The Royal College of Radiologists.Öğe Ultrasonographic evaluation of age-related changes in bowing of the flexor retinaculum(Springer, 2004) Altinok, T; Karakas, HMThe effects of age, gender, and hand dominance on bowing of the flexor retinaculum, used in diagnosing carpal tunnel syndrome, were analyzed. Forty men aged 23-58 years old (39.7 +/- 11.2) and 40 women aged 2057 years old (39.6 +/- 11.3) were the normal subjects. A total of 160 wrists was examined with a linear array transducer. Bowing of the flexor retinaculum was measured as the distance from a line drawn between the trapezium and the hamate to the palmar apex of the outer surface of the flexor retinaculum. It was 0.5-3.7 mm (2.00 +/- 0.64) for all hands, 0.6-3.7 mm (2.06 +/- 0.62) for men, 0.5-3.4 mm (1.96 +/- 0.67) for women, 0.5-3.4 mm (1.00 +/- 0.64) for dominant, and 0.6-3.7 mm (2.03 +/- 0.65) for nondominant hands. There was no difference between genders or dominant vs nondominant hands regarding this parameter. However, it was highly correlated with age (r = 0.59, p < 0.0001). In conclusion, bowing of the flexor retinaculum measurements should be carefully compared with the standardized values when diagnosing carpal tunnel syndrome.Öğe An unusual case of acute disseminated encephalomyelitis confined to brainstem(Elsevier Science Inc, 2004) Firat, AK; Karakas, HM; Yakinci, C; Altinok, T; Alkan, A; Biçak, UAcute disseminated encephalomyelitis (ADEM) is an immune-mediated demyelinating disorder usually encountered in children or adolescents and characterized by multifocal neurological deficits of rapid onset. Typical target areas of demyelination include the corona radiata, centrum semiovale, periventricular white matter, cerebellar peduncles and brainstem. Involvement of deep gray matter nuclei is also frequent. We report a 6-year-old boy with ADEM who had only brainstem involvement. Serial magnetic resonance images representing the stage of disease and response to steroid treatment are presented. (C) 2004 Elsevier Inc. All rights reserved.
