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Featured researches published by Okkes Ibrahim Karahan.


European Journal of Radiology | 2011

Value of multislice computed tomography in the diagnosis of acute mesenteric ischemia

Ali Yikilmaz; Okkes Ibrahim Karahan; Serkan Senol; Ibrahim Sacit Tuna; Hizir Akyildiz

OBJECTIVE To define the value of multislice computed tomography (CT) in the diagnosis of acute mesenteric ischemia (AMI). MATERIALS AND METHODS Two hundred patients (age range: 20-92 years) who were referred to the emergency CT department with a clinical suspicion of AMI were prospectively included in the study. CT examinations were performed with a multislice (16) CT scanner and the protocol included pre-contrast, arterial and venous phase acquisitions. Images were evaluated by using multiplanar reconstruction, maximum intensity projection and volume-rendering techniques at the CT workstation. RESULTS Ninety-four patients (47%) underwent surgery for AMI or for other causes of acute abdominal pain. One hundred-six patients (53%) were followed conservatively according to clinical, radiologic and laboratory findings. Of the 94 patients who underwent surgery, 49 (25%) were found to have AMI. All of these 49 patients with a proven AMI diagnosis were diagnosed with CT. In the other 45 patients who underwent surgery, CT findings were negative for AMI. None of the patients, who were followed conservatively, were eventually diagnosed as having AMI except 1 patient. This patient was unfit for surgery although his clinical and radiologic findings were consistent with AMI and died in 3 days. The sensitivity and specificity values of CT for the detection of AMI were calculated to be 100% for each. CONCLUSIONS Multislice CT is an effective imaging technique for the diagnosis of AMI with excellent sensitivity and specificity values.


Acta Radiologica | 2004

Alveolar echinococcosis of the liver: correlative color Doppler US, CT, and MRI study

Abdulhakim Coskun; Mustafa Öztürk; Okkes Ibrahim Karahan; N. Erdogan; Ş. Işin; M. Güleç

Purpose: To determine and compare the imaging features of hepatic alveolar Echinococcosis using color Doppler US, CT, and MRI. Material and Methods: Abdominal CT and MRI with and without contrast agents and color Doppler US were performed on seven patients with hepatic alveolar Echinococcosis. The lesions were evaluated for location, features of echogenicity, intensity and density, calcification, and vascular, hilar, and perihepatic involvement. The diagnosis was confirmed histopathologically in all patients. Results: Six patients had solitary lesions, and one displayed multiple lesions. The lesions were generally seen as heterogeneous and hyper‐ or hypoechoic when imaged with color Doppler US, hypodense with CT, and hypointense with MRI, in comparison with the liver parenchyma. Calcification, central necrosis, and small peripheral cysts were observed in six, seven, and four patients, respectively. Vascular flow or contrast enhancement was not observed in any of the cases. A look at the respective advantages of each method reveals that calcification was best rendered visible via CT, small peripheral cysts with T2‐weighted MRI, central necrosis with CT and MRI, and perihepatic invasion with multiplanar MRI. Vascular involvement was revealed by all methods. Conclusion: Color Doppler US, CT, and MR imaging function extremely well as complementary methods in the diagnosis of HAE. Color Doppler US should be performed in these patients owing to its ability to efficiently detect the disease. Knowledge of imaging characteristics makes it possible to radiologically ascertain an early diagnosis.


European Journal of Radiology | 2003

Chest radiography and thoracic computed tomography findings in children who have family members with active pulmonary tuberculosis

Kazim Uzum; Okkes Ibrahim Karahan; Sukru Dogan; Abdulhakim Coskun; Faik Topcu

OBJECTIVE The chest radiography and TCT findings in children who had contacted with adult family members with active pulmonary tuberculosis were compared. The contributions of thoracic computed tomography to the diagnosis of tuberculosis were investigated. METHODS AND MATERIAL The children who were 0-16 years old (n=173) and children of families with an adult member which was diagnosed as pulmonary tuberculosis were evaluated. The children were considered in two groups based on the absence (n=125) or presence (n=48) of complaints and/or ambiguous symptoms such as lack of appetite, mild cough, sweating, history of lung infection, low body weight and those with suspicious chest radiography findings (12 cases) were included in this study. Asymptomatic patients (n=125) did not undergo TCT. Patients who had positive PPD skin tests only received isoniazid. If the TCT demonstrated enlarged lymph nodes or parenchymal lesions, minimally active pulmonary tuberculosis was diagnosed and antituberculous treatment was given. RESULTS AND DISCUSSIONS TCT revealed lymph node enlargement or parenchymal lesions in 39 children (81.2%). Of the 12 children whose CXRs revealed suspicious lymph node enlargement and/or infiltration, five had normal findings in TCT whereas the initial findings were confirmed in the remaining seven. These data suggest that there is a correlation between the presence of ambiguous symptoms in exposed children and TCT findings; chest radiography and TCT findings do not yield parallel findings. All the patients who received anti-TB treatment were resolved in the control examinations. CONCLUSION In this study there is a correlation between presence of ambiguous symptoms and TCT findings, but the chest radiography and TCT findings do not yield harmony in exposed children with ambiguous symptoms (suspicious tuberculosis cases). These observations should be considered in children with symptoms similar to those of exposed children, but with no definite history of exposure. If similar TCT findings observed in such patients, treatment for tuberculosis should be considered.


European Journal of Radiology Extra | 2003

Mediopatellar plica limiting lipoma arborescens in the knee joint: MRI findings

Okkes Ibrahim Karahan; Murat Baykara; Mustafa Güleç; Fuat Duygulu

Abstract Introduction : The magnetic resonance imaging (MRI) findings of patient with a mediopatellar plica limiting lipoma arborescens in the knee joint is presented. Patient : A 31-year-old woman attended the orthopedics outpatient department for swelling and motion limitation in the right knee. Results : Magnetic resonance imaging (MRI) revealed a mediopatellar plica limiting lipoma arborescens located in the knee joint. The characteristics of the lesion in T1-weighted, T2-weighted and T2-weighted fat-suppressed spin-echo images were similar to those of the subcutaneous adipose tissue. These findings were considered to be compatible with lipoma arborescens. Discussion : The presence of a plica in the knee joint may limit intra-articular pathologies. MRI findings in a patient with a mediopatellar plica that limits a rare, benign intra-articular pathology, lipoma arborescens is presented.


Polish Journal of Radiology | 2017

Usefulness of Apparent Diffusion Coefficient of Diffusion-Weighted Imaging for Differential Diagnosis of Primary Solid and Cystic Renal Masses

Mehmet Ozturk; Afra Akinci; Şenol Fatih Elbir; Aylin Okur; Serap Dogan; Okkes Ibrahim Karahan

Summary Background To evaluate the value of diffusion-weighted imaging (DWI) for distinguishing between benign and malignant renal masses. Material/Methods Seventy-five patients with 75 unilateral renal lesions were included, and 75 normal contralateral kidneys served as controls. The lesions were categorized into four groups as malignant cystic, malignant solid, benign cystic and benign solid. The apparent diffusion coefficients (ADCs) were evaluated for two different b values (b=600 s/mm2 and b=1000 s/mm2). Receiving operating characteristic analysis was performed to identify threshold ADCs. Results Sensitivity and specificity were 67% and 77% (p=0.003) at the cutoff value of 1.5 for b=600 s/mm2, and 79% and 62% (p=0.004) at the cutoff value of 1.99 for b=1000 s/mm2 as regards the differentiation between solid benign and malignant renal lesions. Sensitivity and specificity were 78% and 79% (p=0.001) at the cutoff value of 3.1 for b=600 s/mm2, and 86% and 61% (p=0.003) at the cutoff value of 2.9 for b=1000 s/mm2 as regrads the differentiation between benign and malignant cystic renal lesions. Conclusions DWI can be an effective diagnostic method for distinguishing between benign and malignant renal masses.


Radiographics | 2000

Minimally Invasive Treatment of Malignant Hepatic Tumors: At the Threshold of a Major Breakthrough

Gerald D. Dodd; Michael C. Soulen; Robert A. Kane; Tito Livraghi; William R. Lees; Yasuyuki Yamashita; Alison R. Gillams; Okkes Ibrahim Karahan; Hyunchul Rhim


American Journal of Roentgenology | 2001

Tumor recurrence after radiofrequency thermal ablation of hepatic tumors: spectrum of findings on dual-phase contrast-enhanced CT.

Shailendra Chopra; Gerald D. Dodd; Kedar N. Chintapalli; John R. Leyendecker; Okkes Ibrahim Karahan; Hyunchul Rhim


European Radiology | 2005

Hyperintense globus pallidus on T1-weighted MR imaging in acute kernicterus: is it common or rare?

Abdulhakim Coskun; Ali Yikilmaz; Okkes Ibrahim Karahan; Mustafa Akcakus; Ali Manav


Radiology | 2000

Gastrointestinal wall thickening in patients with cirrhosis: Frequency and patterns at contrast-enhanced CT

Okkes Ibrahim Karahan; Gerald D. Dodd; Kedar N. Chintapalli; Hyunchul Rhim; Shailendra Chopra


Journal of Clinical Ultrasound | 2004

New method for the detection of intraperitoneal free air by sonography: scissors maneuver.

Okkes Ibrahim Karahan; Alibekir Kurt; Ali Yikilmaz; Guven Kahriman

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Gerald D. Dodd

University of Texas Health Science Center at San Antonio

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Kedar N. Chintapalli

University of Texas Health Science Center at San Antonio

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Shailendra Chopra

University of Texas Health Science Center at San Antonio

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