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Dive into the research topics where Okan Akhan is active.

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Featured researches published by Okan Akhan.


European Radiology | 2002

Imaging of abdominal tuberculosis

Okan Akhan; Jacques Pringot

Abstract. The concept of ”abdominal tuberculosis” in this review refers to peritoneum and its reflections, gastrointestinal tract, abdominal lymphatic system, and solid visceral organs, as they are subject to varying degrees of involvement alone or in combination. Some features, including free or loculated ascites with thin-mobile septa, smooth peritoneal thickening and enhancement, misty mesentery with large lymph nodes, smudged omental involvement, and advanced ileocecal changes demonstrated by US, CT, or gastrointestinal series are deemed suggestive radiological findings. The diagnosis still requires a high index of suspicion, once the suggestive features have been demonstrated by imaging modalities.


European Journal of Radiology | 1999

Percutaneous treatment of liver hydatid cysts

Okan Akhan; Mustafa Ozmen

Hydatic disease caused by Echinococcus granulosus is an endemic disease and an important public health problem in some countries of the world. The results of surgical treatment are associated with a high rate of mortality, morbidity, postoperative recurrence and a long period of hospital stay and the medical treatment results are still controversial. Although the percutaneous aspiration and treatment of liver hydatid cysts were considered to be contraindicated due to risks of anaphylactic shock and dissemination of clear-crystal fluid into the abdomen, several reports of successful percutaneous treatment of liver hydatid cysts have been published in the literature. Today, percutaneous treatment of liver hydatid cysts is the most effective and reliable treatment procedure in the selected cases. In this review, indications, contraindications, method and techniques, healing criteria, complications, results and importance of the percutaneous treatment of liver hydatid cysts are discussed.


Journal of Oral and Maxillofacial Surgery | 1999

Determination of the anti-inflammatory effects of methylprednisolone on the sequelae of third molar surgery

Emin Esen; Ferda Taşar; Okan Akhan

PURPOSE The anti-inflammatory effect and adrenal suppressive side effect of methylprednisolone sodium succinate (MP) on the postoperative sequelae of third molar surgery were evaluated using objective methods in a double-blind, crossover study. PATIENTS AND METHODS Twenty patients who were to undergo surgical removal of bilateral, symmetrically placed lower third molars were studied. Each patient was given 125 mg MP intravenously before surgery on one side, and a placebo before surgery on the opposite side on a random basis. Ultrasonographic and computed tomographic examinations were performed to determine the amount of facial edema. Trismus was evaluated by measuring maximal interincisal opening, and pain was evaluated by recording the number of standard analgesic tablets used on the day of surgery and the first postoperative day. Hypothalamic-pituitary-adrenal (HPA) axis function was tested by measuring basal plasma cortisol (hydrocortisone) levels preoperatively and postoperatively. The adrenocorticotropic hormone (ACTH) stimulation test also was performed before and after administration of MP, to evaluate adrenal function. RESULTS Statistical analysis of the data indicated a significant decrease in edema, trismus, and pain in the MP group. Plasma cortisol levels showed a nonsignificant decrease in both the MP- and placebo-treated groups. The ACTH stimulation test indicated normal HPA axis function before and after MP administration. No clinically apparent infection, disturbance of wound healing, or other corticosteroid-related complications were noted. Eighteen patients (90%) indicated a preference for the overall postoperative course when MP was used. CONCLUSION In the absence of contraindications for corticosteroid administration, preoperative use of MP appears to be a safe and effective method of reducing postoperative complications in third molar surgery.


Abdominal Imaging | 2008

Echinococcosis of the liver

Benedikt V. Czermak; Okan Akhan; Renate Hiemetzberger; Bettina Zelger; Wolfgang Vogel; Werner Jaschke; Michael Rieger; Sang Yoon Kim; Jae Hoon Lim

Echinococcosis, also known as hydatid disease, is an infection of larval stage animal tapeworm, Echinococcus. The larvae reside in the liver and lungs, producing multiloculated fluid-filled cysts. Imaging findings of Echinococcosis caused by E. granulosus are single, unilocular cyst or multiseptated cysts, showing “wheel-like”, “rosette-like” or “honeycomb-like” appearances. There may be “snow-flakes” sign, reflecting free floating protoscoleces (hydatid-sand) within the cyst cavity. Degenerating cysts show wavy or serpentine bands or floating membranes representing detached or ruptured membranes. Degenerated cysts show heterogeneous, solid-looking pseudotumor that may show “ball of wool sign”. Dead cysts show calcified cyst wall. Echinococcosis caused by E. multilocularis produces multilocular alveolar cysts with exogeneous proliferation, progressively invading the liver parenchyma and other tissues of the body. Imaging findings are ill-defined infiltrating lesions of the liver parenchyma, consisting of multiple small clustered cystic and solid components. On sonography, lesions are heterogeneous with indistinct margins, showing “hailstorm appearance” or “vesicular or alveolar appearance”. CT and MR imaging displays multiple, irregular, ill-defined lesions. Multiple small round cysts with solid components are frequent. Large lesions show “geographical map” appearance. Calcifications are very frequent, appearing as peripheral calcification or punctuate scattered calcific foci. Invasion into the bile ducts, portal vein or hepatic vein may occur. Direct spread of infected tissue may result in cysts in the peritoneal cavity, kidneys, adrenal gland or bones.


European Journal of Radiology | 2002

Percutaneous drainage of abdominal abcess

Süleyman Men; Okan Akhan; Mert Köroğlu

The mortality in undrained abdominal abscesses is high with a mortality rate ranging between 45 and 100%. The outcome in abdominal abscesses, however, has improved due to advances in image guided percutaneous interventional techniques. The main indications for the catheter drainage include treatment or palliation of sepsis associated with an infected fluid collection, and alleviation of the symptoms that may be caused by fluid collections by virtue of their size, like pancreatic pseudocele or lymphocele. The single liver abscesses may be drained with ultrasound guidance only, whereas the multiple abscesses usually require computed tomography (CT) guidance and placement of multiple catheters. The pancreatic abscesses are generally drained routinely and urgently. Non-infected pancreatic pseudocysts may be simply observed unless they are symptomatic or cause problems such as pain or obstruction of the biliary or the gastrointestinal tract. Percutaneous routes that have been described to drain pelvic abscesses include transrectal or transvaginal approach with sonographic guidance, a transgluteal, paracoccygeal-infragluteal, or perineal approach through the greater sciatic foramen with CT guidance. Both the renal and the perirenal abscesses are amenable to percutaneous drainage. Percutaneous drainage provides an effective and safe alternative to more invasive surgical drainage in most patients with psoas abscesses as well.


Acta Radiologica | 2006

Percutaneous placement of central venous catheters: comparing the anatomical landmark method with the radiologically guided technique for central venous catheterization through the internal jugular vein in emergent hemodialysis patients.

Mert Köroğlu; M. Demir; B. K. Koroglu; M. T. Sezer; Okan Akhan; Harun Yildiz; L. Yavuz; Bahattin Baykal; Orhan Oyar

Purpose: To compare the success and immediate complication rates of the anatomical landmark method (group 1) and the radiologically (combined real-time ultrasound and fluoroscopy) guided technique (group 2) in the placement of central venous catheters in emergent hemodialysis patients. Material and Methods: The study was performed prospectively in a randomized manner. The success and immediate complication rates of radiologically guided placement of central venous access catheters through the internal jugular vein (n = 40) were compared with those of the anatomical landmark method (n = 40). The success of placement, the complications, the number of passes required, and whether a single or double-wall puncture occurred were also noted and compared. Results: The groups were comparable in age and sex. The indication for catheter placement was hemodialysis access in all patients. Catheter placement was successful in all patients in group 2 and unsuccessful in 1 (2.5%) patient in group 1. All catheters functioned adequately and immediately after the placement (0% initial failure rate) in group 2, but 3 catheters (7.5% initial failure rate) were non-functional just after placement in group 1. The total number of needle passes, double venous wall puncture, and complication rate were significantly lower in group 2. Conclusion: Percutaneous central venous catheterization via the internal jugular vein can be performed by interventional radiologists with better technical success rates and lower immediate complications. In conclusion, central venous catheterization for emergent dialysis should be performed under both real-time ultrasound and fluoroscopic guidance.


CardioVascular and Interventional Radiology | 2005

Percutaneous Drainage of 300 Intraperitoneal Abscesses with Long-Term Follow-Up

Devrim Akinci; Okan Akhan; Mustafa Ozmen; Nevzat Karabulut; Orhan S. Ozkan; Barbaros Cil; Musturay Karcaaltincaba

The purpose of the study was to evaluate the efficacy of percutaneous drainage of intraperitoneal abscesses with attention to recurrence and failure rates. A retrospective analysis of percutaneous treatment of 300 intraperitoneal abscesses in 255 patients (147 male, 108 female; average age: 38 years; range: 40 days to 90 years) for whom at least 1-year follow-up data were available was performed. Abscesses were drained with fluoroscopic, sonographic, or computed tomographic guidance. Nine abscesses were drained by simple aspiration; catheter drainage either by Seldinger or trocar technique was used in the remaining 291 abscesses with 6F to 14 F catheters. Initial cure and failure rates were 68% (203/300) and 12% (36/300), respectively. Sixty-one abscesses (20%) were either palliated or temporized. The recurrence rate was 4% (12/300) and nine of them were cured by recatheterization, whereas three of them were treated by medication or surgery. The overall success and failure rates were 91% (273/300) and 9% (27/300), respectively, with temporized, palliated, and recatheterized recurred abscesses. The 30-day mortality rate was 3.1% (8/255). The mean duration of catheterization was 13 days. Intraperitoneal abscesses with safe access routes should be drained percutaneously because of high success and low morbidity, mortality, and recurrence rates.


CardioVascular and Interventional Radiology | 1994

Percutaneous treatment of pulmonary hydatid cysts

Okan Akhan; Mustafa Ozmen; Alp Dinçer; Ayhan Göçmen; Fuat Kalyoncu

PurposeTo evaluate the safety and efficacy of percutaneous drainage of pulmonary hydatid cysts.MethodsEleven pulmonary hydatid cysts in eight patients were drained percutaneously after 1–2 years of treatment with mebendazole (50 mg/kg/day). Percutaneous needle aspiration was carried out under ultra-sound (US) in six patients and computed tomography (CT) in two patients. Nine cysts were close to, and two cysts were distant from the thoracic wall. After aspiration, hypertonic (15%) saline solution was instilled for up to 35% of the estimated volume of the cyst and aspirated 5–10 min later. Follow-up ranged from 8 to 31 months (mean 16.3 months).ResultsNeither anaphylactic shock nor death occurred in any of the eight patients. One patient developed fever, ipsilateral hydropneumothorax, and contralateral pleural effusion. One patient suffered from fever, pneumothorax, and abscess and was treated surgically; one developed fever and dyspnea. The volume reduction during follow-up was 47%–93%. The cystic contents turned into a pseudotumor appearance with a thick irregular contour on CT and higher Hounsfield units. On US, the cysts showed a heterogeneous content with internal echoes representing detached and degenerated membranes, and the fluid content almost completely disappeared.ConclusionWe believe that percutaneous therapy of pulmonary hydatid disease is an effective alternative to surgical treatment in patients who have failed medical therapy.


British Journal of Radiology | 1991

Spinal intradural hydatid cyst in a child

Okan Akhan; Alp Dinçer; Isil Saatci; Nadir Gülekon; Aytekin Besim

Hydatid disease is an infestation by the larval stages of Echinococcus granulosus. In man, the liver and lungs are the organs most frequently involved. In the spinal column, hydatid disease usually begins in the vertebral body. Extension into the spinal canal results in spinal cord compression. Intradural hydatid cyst is extremely rare compared with the other types of spinal hydatid lesions (Rayport et al, 1964; Ley & Marti, 1970; Pamir et al, 1984). A 6-year-old boy was admitted to hospital because of progressive paraplegia, which had started 2 months previously. He was said to have lost bladder and bowel control in the last few weeks. Physical examination revealed marked reduction in the motor power of the lower limbs. There was bilateral clonus, a positive Babinskis sign and hyperactivity of the deep tendon reflexes at the lower extremities.


European Journal of Radiology | 2002

Percutaneous radiologic gastrostomy.

Mustafa Ozmen; Okan Akhan

Gastrostomy is a preferred method of nutrition in patients with impaired ability to eat. Although surgical gastrostomy is a well-established method and has been widely performed in the last century, beginning with early 1980s, percutaneous gastrostomy techniques, either endoscopic or radiologic, has widely gained acceptance. As percutaneous methods have been shown to be an effective, safe, easy to perform and low-cost techniques with low morbidity and mortality rates, nowadays percutaneous gastrostomy is the first method of choice in need of nutrition in patients with functioning gut. In this article authors review the technique of percutaneous radiologic gastrostomy, as well as indications, contraindications, variations of technique, ethical considerations, controversies and comparison with surgical and endoscopic methods.

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Baris Turkbey

National Institutes of Health

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Mert Köroğlu

Süleyman Demirel University

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