Okan DİLEK

Mr. Okan DİLEK

orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 April 2021 in Acta Radiologica
Verified
Journal Article
Closed access
PDF file
ODOkan DİLEK
Okan DİLEK
EDEmin Demirel
Emin Demirel
HAHüseyin Akkaya
Hüseyin Akkaya
MBMehmet Cenk Belibagli
Mehmet Cenk Belibagli
GSGokhan Soker
Gokhan Soker
BGBozkurt Gulek
Bozkurt Gulek
Background: Computed tomography (CT) gives an idea about the prognosis in patients with COVID-19 lung infiltration. Purpose: To evaluate the success rates of various scoring methods utilized in order to predict survival periods, on the basis of the imaging findings of COVID-19. Another purpose, on the other hand, was to evaluate the agreements among the evaluating radiologists. Material and Methods: A total of 100 cases of known COVID-19 pneumonia, of which 50 were deceased and 50 were living, were included in the study. Pre-existing scoring systems, which were the Total Severity Score (TSS), Chest Computed Tomography Severity Score (CT-SS), and Total CT Score, were utilized, together with the Early Decision Severity Score (ED-SS), which was developed by our team, to evaluate the initial lung CT scans of the patients obtained at their initial admission to the hospital. The scans were evaluated retrospectively by two radiologists. Area under the curve (AUC) values were acquired for each scoring system, according to their performances in predicting survival times. Results: The mean age of the patients was 61 ± 14.85 years (age range = 18–87 years). There was no difference in co-morbidities between the living and deceased patients. The survival predicted AUC values of ED-SS, CT-SS, TSS, and Total CT Score systems were 0.876, 0.823, 0.753, and 0.744, respectively. Conclusion: Algorithms based on lung infiltration patterns of COVID-19 may be utilized for both survival prediction and therapy planning.

15 November 2024 in Diagnostics
Verified
Journal Article
Open access
PDF file
HAHüseyin Akkaya
Hüseyin Akkaya
ODOkan DİLEK
Okan DİLEK
SÖSelim Özdemir
Selim Özdemir
TÖTurgay Öztürkçü
Turgay Öztürkçü
MGMustafa Gürbüz
Mustafa Gürbüz
BGBozkurt Gülek
Bozkurt Gülek
Objectives: To evaluate the agreement among radiologists in the evaluation of rectal cancer staging and restaging (after neoadjuvant therapy) and assess whether locoregional recurrence can be predicted with this information. Materials and Methods: Pre-neoadjuvant and after-neoadjuvant therapy magnetic resonance imaging (MRI) examinations of 239 patients diagnosed with locally advanced rectal cancer were retrospectively reviewed by three radiologists. The agreement between the MRI findings (localization of tumor involvement, tumor coverage pattern, external sphincter involvement, mucin content of the mass and lymph node, changes in the peritoneum, MRI T stage, distance between tumor and MRF, submucosal sign, classification of locoregional lymph node, and EMVI) was discussed at the September 2023 meeting of the Society of Abdominal Radiology (SAR) and the interobserver and histopathological findings were examined. The patients were evaluated according to locoregional rectal cancer and lateral lymph node (LLN) staging, and re-staging was performed using MRI images after neoadjuvant treatment. The ability of the locoregional and LLN staging system to predict locoregional recurrence was evaluated. Results: Among the parameters examined, for the MRI T stage and distance between the tumor and the MRF, a moderate agreement (kappa values: 0.61–0.80) was obtained, while for all other parameters, the interobserver agreement was notably high (kappa values 0.81–1.00). LLNs during the restaging with an OR of 2.1 (95% CI = 0.33–4.87, p = 0.004) and a distance between the tumor and the MRF of less than 1 mm with an OR of 2.1 (95% CI = 1.12–3.94, p = 0.023) affected locoregional recurrence. A multivariable Cox regression test revealed that the restaging of lymph nodes among the relevant parameters had an impact on locoregional recurrence, with an OR of 1.6 (95% CI = 0.32–1.82, p = 0.047). With the LLN staging system, an increase in stage was observed in 37 patients (15.5%), and locoregional recurrence was detected in 33 of them (89.2%) (p < 0.001). Conclusions: LLN staging is not only successful in predicting locoregional recurrence among MRI parameters but is also associated with a very high level of interobserver agreement. The presence of positive LLN in the restaging phase is one of the most valuable MRI parameters for poor prognosis.


1 October 2021 in Revista da Associação Médica Brasileira
Verified
Journal Article
Open access
HAHüseyin Akkaya
Hüseyin Akkaya
AKAlper Kizilog˘lU
Alper Kizilog˘lU
ODOkan DİLEK
Okan DİLEK
MBMehmet Cenk Belibağlı
Mehmet Cenk Belibağlı
ÖKÖmer Kaya
Ömer Kaya
BGBozkurt Gülek
Bozkurt Gülek
This study aimed to investigate whether the volume and morphology of the olfactory bulb are effective in the occurrence of anosmia in patients after COVID-19 infection. The olfactory bulbus volume was calculated by examining the brain magnetic resonance imaging of cases with positive (+) COVID-19 polymerase chain reaction test with and without anosmia. Evaluated magnetic resonance imaging images were the scans of patients before they were infected with COVID-19. The olfactory bulbus and olfactory nerve morphology of these patients were examined. The brain magnetic resonance imaging of 59 patients with anosmia and 64 controls without anosmia was evaluated. The olfactory bulb volumes of both groups were calculated. The olfactory bulb morphology and olfactory nerve types were examined and compared between the two groups. The left and right olfactory bulb volumes were calculated for the anosmia group and control group as 47.8±15/49.3±14.3 and 50.5±9.9/50.9±9.6, respectively. There was no statistically significant difference between the two groups. When the olfactory bulb morphology was compared between the two groups, it was observed that types D and R were dominant in the anosmia group (p<0.05). Concerning olfactory nerve morphology, type N was significantly more common in the control group (p<0.05). According to our results, the olfactory bulb volume does not affect the development of anosmia after COVID-19. However, it is striking that the bulb morphology significantly differs between the patients with and without anosmia. It is clear that the evaluation of COVID-19-associated smell disorders requires studies with a larger number of patients and a clinicoradiological approach.

20 September 2021 in Diagnostic and Interventional Radiology
Verified
Journal Article
Closed access
ODOkan DİLEK
Okan DİLEK
ÖKÖmer Kaya
Ömer Kaya
HAHüseyin Akkaya
Hüseyin Akkaya
CCCem Ceylan
Cem Ceylan
AKAlper Kiziloglu
Alper Kiziloglu
BGBozkurt Gulek
Bozkurt Gulek
PURPOSE We aimed to evaluate the use of the COVID-19 reporting and data system (CO-RADS) among radiologists and the diagnostic performance of this system. METHODS Four radiologists retrospectively evaluated the chest CT examinations of 178 patients. The study included 143 patients with positive reverse transcriptase-polymerase chain reaction (RT-PCR) test results and 35 patients whose RT-PCR tests were negative but whose clinical and/or radiological findings were consistent with COVID-19. Fleiss' kappa (kappa) values were calculated, and individual observers' scores were compared. To investigate diagnostic efficiency, receiver operating characteristic (ROC) curves were calculated for each interpreter. RESULTS The interpreters were in full agreement on 574 of 712 (80.6%) evaluations. The common Fleiss'. value of all the radiologists combined was 0.712 (95% confidence interval [CI] 0.692-0.769). A reliable prediction on the basis of RT-PCR and clinical findings indicated the mean area under the curve (AUC) of Fleiss'. value as 0.89 (95% CI 0.708-0.990). General interpreter agreement was found to range from moderate to good. CONCLUSION The interpreter agreement for CO-RADS categories 1 and 5 was reasonably good. We conclude that this scoring system will make a valuable contribution to efforts in COVID-19 diagnosis. CORADS can also be of significant value for the diagnosis and treatment of the disease in cases with false-negative PCR results.