Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Onur Tutar is active.

Publication


Featured researches published by Onur Tutar.


Journal of Pediatric Gastroenterology and Nutrition | 2014

Shear wave elastography in the evaluation of liver fibrosis in children.

Onur Tutar; Ömer Faruk Beşer; Ibrahim Adaletli; Necmettin Tunc; Didem Gülcü; Fatih Kantarci; Ismail Mihmanli; Fügen Çokuğraş; Tufan Kutlu; Gulsen Ozbay; Tülay Erkan

Background: Shear-wave elastography (SWE) is a novel noninvasive method that involves application of local mechanical compression on soft tissue using focused ultrasonography and acquiring strain images that show tissue response. In this study, our goal was to assess the performance of SWE in the staging of liver fibrosis in children with chronic liver disease. Methods: The study involved measuring SWE values in the right lobe of the liver in a patient group of 76 children with chronic liver disease and a control group of 50 healthy subjects. In the patient group, the shear elastic modulus values were correlated with biopsy results according to the Brunt scoring system (F0: portal fibrosis, F1: perisinusoidal or portal/periportal fibrosis, F2: both perisinusoidal and portal/periportal fibrosis, F3: bridging fibrosis, and F4: cirrhosis). Performance of SWE in estimating liver fibrosis in children was determined based on a receiver-operating characteristics (ROC) analysis. Results: Mean SWE values of the control group and F0 group were not statistically significantly different (P = 0.106). The mean SWE values of the F1, F2, F3, and F4 groups were higher than that of the control group (all P < 0.001). Based on kiloPascal measurement values, the area under the ROC curve was 95.2% (95% confidence interval [CI] 92.1–99.5), with a sensitivity for diagnosing liver fibrosis of 91.5%, a specificity of 94.0%, a positive predictive value of 93.1%, and a negative predictive value of 92.6%. Based on meter-per-second measurement values, the area under the ROC curve was 96.3% (95% CI 92.7–99.8), with a sensitivity for diagnosing liver fibrosis of 93.2%, a specificity of 94.0%, a positive predictive value of 93.2%, and a negative predictive value of 94.0%. Mean SWE values for patients with nonalcoholic steatohepatitis were higher than those in the remainder of the study group. Conclusions: Although liver fibrosis can be detected using SWE, differentiation of fibrosis stages could not be achieved. The presence of steatosis significantly increased the mean SWE values on elastography and so care should be taken when assessing children with nonalcoholic steatohepatitis.


Seminars in Arthritis and Rheumatism | 2013

Aortic and coronary calcifications in Takayasu arteritis

Emire Seyahi; Ayca Ucgul; Deniz Cebi Olgun; Serdal Ugurlu; Canan Akman; Onur Tutar; Sebahattin Yurdakul; Hasan Yazici

OBJECTIVES Atherosclerosis is well recognized in Takayasu arteritis (TAK) and the associated plaques tend to be more common in areas of arteritis. We now report arterial wall calcification in a large group of TAK patients and controls. We hypothesized that the degree of coronary artery calcification would point to a systemic effect of inflammation while that in the thoracic aorta more of local inflammation. METHODS A total of 47 patients with TAK, 43 patients with SLE and 70 healthy controls (HC) were studied. The presence of coronary artery and thoracic aorta calcifications (ToAC) was investigated by multi-detector computed tomography (MDCT). Atherosclerotic plaques in the carotid arteries were screened using B mode ultrasound. RESULTS The frequency of coronary artery calcification was significantly increased among patients with SLE as compared to the healthy controls while the increase in TAK did not reach statistical significance. There were more TAK patients with ToAC among the TAK as compared to the SLE patients [21/47 (45%) vs 10/43 (23%), P = 0.033]. In addition, a circumferential type of calcification, vs a punctuate or linear type, was the more common type in 67% of patients with TAK whereas only the linear or punctuate type was seen in SLE patients and HC. SLE and TAK patients were found to have increased risk for carotid artery plaques. Among TAK patients, coronary artery calcification, ToAC and carotid artery plaques tend to be at sites of primary vasculitic involvement. CONCLUSIONS There is increased atherosclerosis in TAK and SLE. Vessel wall inflammation seems to be also important in the atherosclerosis associated with TAK.


European Journal of Paediatric Neurology | 2009

Diffusion-weighted magnetic resonance imaging findings of a patient with neonatal citrullinemia during acute episode

Batuhan Kara; Sait Albayram; Onur Tutar; Gürkan Altun; Naci Kocer; Civan Islak

Reports on citrullinemia usually describe the imaging findings in the adult form of the disease. However, neuroimaging findings of neonatal cases are seldom reported. We report on the diffusion-weighted magnetic resonance imaging (MRI) findings of a one-year old infant with neonatal citrullinemia during an acute episode and discuss possible underlying mechanisms for abnormal diffusion findings.


Iranian Journal of Radiology | 2015

Perianal Fistula With and Without Abscess: Assessment of Fistula Activity Using Diffusion-Weighted Magnetic Resonance Imaging

Selim Bakan; Deniz Cebi Olgun; Sedat Giray Kandemirli; Onur Tutar; Cesur Samanci; Suleyman Dikici; Osman Simsek; Babak Rafiee; Ibrahim Adaletli; Ismail Mihmanli

Background: Magnetic resonance imaging (MRI) is highly accurate for the depiction of both the primary tract of fistula and abscesses, in patients with perianal disease. In addition, MRI can be used to evaluate the activity of fistulas, which is a significant factor for determining the therapeutic strategy. Objectives: This study aimed to determine the usefulness of diffusion-weighted (DW) MRI for assessing activity and visibility of perianal fistula. Patients and Methods: Fifty-three patients with 56 perianal fistulas were included in the current retrospective study. The T2-weighted imaging (T2WI) and DWMRI were performed and apparent diffusion coefficient (ADC) values of fistulas were measured. Fistulas were classified into two groups: only perianal fistulas and fistulas accompanied by abscess. Fistulas were also classified into two groups, based on clinical findings: positive inflammatory activity (PIA) and negative inflammatory activity (NIA). Results: Mean ADC value (mm2/s) of PIA group was significantly lower than that of NIA group, regarding lesions in patients with abscess-associated fistulas (1.371 × 10-3 ± 0.168 × 10-3 vs. 1.586 × 10-3 ± 0.136 × 10-3; P = 0.036). No statistically significant difference was found in mean ADC values between PIA and NIA groups, in patients with only perianal fistulas (P = 0.507). Perianal fistula visibility was greater with combined evaluation of T2WI and DWMRI than with T2WI, for two reviewers (P = 0.046 and P = 0.014). Conclusion: The DWMRI is a useful technique for evaluating activity of fistulas with abscess. Perianal fistula visibility is greater with combined T2WI and DWMRI than T2WI alone.


International Surgery | 2014

Characteristics of Patients With Spontaneous Splenic Rupture

Pınar Kocael; Osman Simsek; İsmail Ahmet Bilgin; Onur Tutar; Kaya Saribeyoglu; Salih Pekmezci; Ertuğrul Göksoy

In the present study, we aim to share our clinical experience in patients with spontaneous splenic rupture. Splenic rupture without trauma is known as spontaneous splenic rupture. The major problems in the management of spontaneous splenic rupture are missed or delayed diagnosis due to the lack of trauma in most cases. The records of all patients, who were admitted to Cerrahpaşa Medical Faculty, Istanbul University, were retrospectively reviewed from January 2000 to March 2013. Twelve patients were admitted to the emergency department and they were diagnosed with spontaneous splenic rupture. The mean age was 47.6 years. All patients had complaints of abdominal pain. The mean hematocrit value was 22%. Radiologic assessment revealed hemoperitoneum and/or subcapsular hematoma in 8 patients while splenic abscess was diagnosed in 2 patients. Eleven patients underwent splenectomy whereas one was managed conservatively. The most common cause of spontaneous splenic rupture was determined to be use of anticoagulants. Etiology was considered to be idiopathic in 1 patient. Two patients died in the postoperative period. Although rare, spontaneous splenic rupture must be suspected in emergency patients who have used especially anticoagulants and antiaggregants and who have had no recent history of trauma. One of the important causes of mortality is missed or delayed diagnosis.


The Annals of Thoracic Surgery | 2015

Intrathoracic Gossypiboma After Spinal Operation

Selim Bakan; Sedat Giray Kandemirli; Gokhan Kuyumcu; Ezel Ersen; Onur Tutar

Gossypiboma is a rare surgical complication, with an estimated incidence of 1/1,000 to 1/10,000 per operation. Gossypiboma is an aseptic foreign body reaction with fibrosis and granuloma formation secondary to retained surgical sponges. The main sites of involvement are the abdomen, pelvis, and thorax. Intrathoracic gossypiboma poses diagnostic challenges because the surgical history may include extrathoracic operations and imaging findings can be atypical. We describe a patient with intrathoracic gossypiboma secondary to posterior vertebral body screw fixation after a traumatic injury. This case illustrates that thoracotomy history may not necessarily be found in intrathoracic gossypiboma.


Polish Journal of Radiology | 2015

Thoracic Splenosis after a Gunshot: Diffusion-Weighted MRI Findings

Onur Tutar; Selim Bakan; Cesur Samanci; Fuat Nurili; Haluk Sayman; Canan Akman

Summary Background Intrathoracic splenosis is a rare condition resulting from concomitant rupture of the spleen and left hemidiaphragm after a traumatic event involving the spleen and the diaphragma and is defined as autotransplantation of splenic tissue in thorax. Case Report The aim of this study was to present a case report of a combined intrathoracic and subcutaneous splenosis in a patient 19 years after penetrating trauma. She has left dorsal side pain and routine chest roentgenogram shows pleural nodular masses. The patient was referred to us for radiologic work up. Conclusions The MRI scans revealed the intrathoracic and subcutan masses as mainly hypointense on T1-weighted images and hyperintense on T2-weighted images and significant restriction in diffusion-weighted images. Scintigraphy revealed abnormal hot spots in subcutaneous tissue and diaphragmatic pleura of the left hemithorax.


Case Reports | 2012

Quadriceps fat-pad impingement syndrome: MRI findings

Ahmet Bas; Onur Tutar; Inanc Yanik; Cesur Samanci

A 32-year-old man was referred to a radiology department for intermittent anterior knee pain and swelling for approximately 6 months. The patient denied any history of major trauma, fracture or infection. MRI was performed to diagnose the cause of knee pain. The axial view of MRI revealed increased patellofemoral joint effusion and the sagittal view of T1-weighted, and T2-weighted MRIs showed an oedema, increased intra-articular fluid and thickening of suprapatellar fat pad (figures 1 and 2). Also, oedema …


Polish Journal of Radiology | 2015

A Rare Complication of the Thyroid Malignancies: Jugular Vein Invasion.

Atilla Suleyman Dikici; Onur Yıldırım; Mehmet Emin Er; Fahrettin Kilic; Onur Tutar; Fatih Kantarci; Ismail Mihmanli

Summary Background Unilateral invasion of the internal jugular vein (IJV) after subtotal thyroidectomy caused by local recurrence of papillary thyroid carcinoma is extremely rare. We report a case of papillary thyroid carcinoma which invades IJV with hypervascular tumor thrombus. Case Report We report a case of a 52-year-old woman with a history of previous thyroid operation who presented with a 2-month history of a painless, growing, hard, solitary mass on the left side of the neck. Clinical examination revealed also ipsilateral cervical lymphadenopathy. Radiological examination showed a necrotic and cystic mass arising from the operated area extending and invading the left jugular vein wall with hypervascular tumor thrombus. Cytological examination of the mass confirmed a papillary thyroid carcinoma (PTC) and enlarged metastatic lymph nodes. Therefore, total thyroidectomy with left neck dissection and segmental resection of the left internal jugular vein were performed, and the tumor thrombus was cleared successfully. Conclusions Invasion of IJV with hypervascular tumor thrombosis is an extremely rare condition in papillary thyroid carcinoma. Thrombosis of IJV is probably underdiagnosed. Early-stage diagnosis is important for long-term survival rates.


Renal Failure | 2014

A new method for computer-assisted detection, definition and differentiation of the urinary calculi.

Duzgun Yildirim; Ovunc Ozturk; Onur Tutar; Fuad Nurili; Halil Bozkurt; Huseyin Kayadibi; Ercan Karaarslan; Selim Bakan

Abstract Purpose: Urinary stones are common and can be diagnosed with computed tomography (CT) easily. In this study, we aimed to specify the opacity characteristics of various types of calcified foci that develop through the urinary system by using an image analysis program. With this method, we try to differentiate the calculi from the non-calculous opacities and also we aimed to present how to identify the characteristic features of renal and ureteral calcules. Materials and methods: We obtained the CT studies of the subjects (n = 48, mean age = 41 years) by using a dual source CT imaging system. We grouped the calculi detected in the dual-energy CT sections as renal (n = 40) or ureteric (n = 45) based on their locations. Other radio-opaque structures that were identified outside but within close proximity of the urinary tract were recorded as calculi “mimickers”. We used ImageJ program for morphological analysis. All the acquired data were analyzed statistically. Results: According to thorough morphological parameters, there were statistically significant differences in the angle and Feret angle values between calculi and mimickers (p < 0.001). Multivariate logistical regression analysis showed that Minor Axis and Feret angle parameters can be used to distinguish between ureteric (p = 0.003) and kidney (p = 0.001) stones. Conclusions: Computer-based morphologic parameters can be used simply to differentiate between calcular and noncalcular densities on CT and also between renal and ureteric stones.

Collaboration


Dive into the Onur Tutar's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge