Fakülteler / Faculties
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Item Prostate Mucinous Carcinoma Treated with Definitive Radiotherapy and Hormonal Therapy: Case Report and Review of the Literature(2014) Guler, Ozan Cem; Onal, Cem; Erbay, Gurcan; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0002-2742-9021; https://orcid.org/0000-0002-1706-8680; 24365124; AAC-5654-2020; HOC-5611-2023; AAK-5370-2021Prostate mucinous carcinoma (MC) is a rare variant of prostate adenocarcinoma that is characterized by large pools of extracellular mucin, which by definition compose at least 25% of the tumor volume. Prostate MC has 3 subtypes. The most common variant is pure MC; primary signet ring cell carcinoma and MC with signet ring cell are less common variants and are more aggressive than pure MC. Because of the rarity of prostate MC and conflicting reports regarding the behavior of the disease, the optimal treatment strategy is not clear. Most series report the efficacy of surgery. We report a rare case of a patient with a large prostate MC that was treated successfully with hormone therapy (HT) and radiotherapy (RT). Treatment response was assessed by dynamic contrast-enhanced magnetic resonance imaging (MRI). (C) 2014 Elsevier Inc. All rights reserved.Item Uterine Perforation During 3-Dimensional Image-Guided Brachytherapy in Patients With Cervical Cancer Baskent University Experience(2014) Onal, Cem; Guler, Ozan Cem; Dolek, Yemliha; Erbay, Gurcan; https://orcid.org/0000-0002-2742-9021; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0002-1706-8680; 24407583; HOC-5611-2023; AAC-5654-2020; AAK-5370-2021Objectives This study aimed to determine the incidence and characteristics of uterine perforation at our department using 3-dimensional computed tomography (CT)-based brachytherapy (BRT). The characteristics of the patients presenting with perforation and impact of the perforation on the treatment course were also analyzed. Materials and Methods The clinical and radiologic data of 200 patients with biopsy-proven cervical cancer treated using CT-based BRT were retrospectively evaluated. All patients had undergone tandem-based intracavitary BRT, and 67 patients had undergone magnetic resonance imaging (MRI) before BRT. Results Of the 200 patients, 17 (8.5%) had uterine perforation. Of the 626 applications with CT images, 30 (4.8%) resulted in uterine perforation. The median age of patients with perforation was higher (68 years; range, 44-89 years) than that of the patients without perforation (59 years; range, 21-87 years), and the mean (SD) tumor size at diagnosis was larger in patients with perforation (7.0 [1.5] cm) than in patients without perforation (5.0 [1.5] cm). The most frequent perforation site was the posterior uterine wall (8 patients), followed by the fundus (5 patients) and anterior wall (4 patients). Of the 7 patients with a retroverted uterus, 4 had uterine perforation during BRT. In 67 patients with MRI delivered before BRT, only 3 (4%) had uterine perforation, and 2 of the 3 patients with uterine perforation had a retroverted uterus. However, of the 133 patients with no MRI evaluation before BRT, 14 (11%) had uterine perforation. No life-threatening complications or signs of intraperitoneal tumor cell seeding were observed. Conclusions Older age, larger tumors, a retroverted uterus, and a stenotic cervical os were all predisposing factors for uterine perforation during BRT. Preoperative MRI is a feasible and safe method to decrease the risks of uterine perforation and could be used preoperatively in centers where intraoperative ultrasonography is not used in routine practice.Item Spontaneous Giant Splenic Hydatid Cyst Rupture Causing Fatal Anaphylactic Shock: A Case Report and Brief Literature Review(2014) Belli, Sedat; Akbulut, Sami; Erbay, Gurcan; Kocer, Nazim Emrah; https://orcid.org/0000-0002-1706-8680; https://orcid.org/0000-0002-5943-9283; 24918138; AAK-5370-2021; AAM-5436-2021Hydatid disease is a parasitic infection characterized by cyst formation in any organ, although the liver and lungs are most commonly involved. Hydatid disease of the spleen is uncommon, representing <8% of all human hydatid diseases. Splenic hydatid cysts usually coexist with liver hydatid cysts (secondary form), although the spleen is the primary location (primary form) in some cases. The clinical signs and symptoms of splenic hydatid cysts depend on their size, relationship with adjacent organs, and complications. One of the complications of splenic hydatid cysts is cyst rupture either after trauma or spontaneously as a result of increased intracystic pressure. These cysts may rupture into a hollow organ, through the diaphragm into the pleural cavity, or directly into the peritoneal cavity. A splenic hydatid cyst that ruptures into the peritoneal cavity may cause complications, including signs of peritoneal irritation, urticaria, anaphylaxis, and death, as in our case. Therefore, a hydatid cyst rupture requires both emergency surgery and careful postoperative care. In this study, we present a case of a giant splenic hydatid cyst that ruptured into the peritoneal cavity without any trauma. A review of cases reported in the English literature about splenic hydatid cyst perforation is also discussed.Item Optimal b Value in Diffusion-Weighted Imaging for Differentiation of Abdominal Lesions(2014) Koc, Zafer; Erbay, Gurcan; https://orcid.org/0000-0003-0987-1980; https://orcid.org/0000-0002-1706-8680; 24115207; S-8384-2016; AAK-5370-2021Purpose: To explore the optimal b value in diffusion-weighted imaging (DWI) for differentiation of benign and malignant abdominal lesions. Materials and Methods: A total of 108 consecutive patients (age 60 +/- 12.5 years) with 127 pathologically confirmed diagnoses of abdominal lesions were included. Single-shot echoplanar imaging (SH-EPI) DWI (1.5T) with seven b values and eight apparent diffusion coefficient (ADC) maps were obtained. The lesions were analyzed visually on DWI and ADC maps for benignity/malignity using a 5-point scale and by measuring the ADC values and ADC lesion/normal parenchyma ADC ratio. ROC analysis was used to evaluate the diagnostic accuracy of ADC for differentiating between benign and malignant lesions. Pathology results were the reference standard. Results: Differentiation between malignant and benign lesions using visual scoring was successful at b values of 600 or higher (sensitivities, specificities, and accuracies were 100/93.8/92.5, 84.7/82.6/80.4, and 94.4/89.7/88.1, respectively, for b600, 800, and 1000). The mean ADC values of malignant lesions were significantly lower than those of benign lesions for all b-value combinations except b0 and 50 s/mm(2) (P = 0.032 for b0 and 50 s/mm(2), P = 0.000 for other b values). The best b-value combination was 0 and 600 s/mm(2) and multiple b2. The lesion/normal parenchymal ADC ratio for b600, b1000, and multiple b2 better distinguished between benign and malignant lesions. Conclusion: In DWI, the optimal b value is 600 s/mm(2); multiple b values of 600 s/mm(2) and higher are recommended to differentiate between benign and malignant abdominal lesions. The lesion ADC/normal parenchyma ADC ratio is more accurate than using lesion ADC only.Item On Visualization and Quantification of Lesion Margin in CT Liver Images(2020) Arica, Sami; Altuntas, Tugce Sena; Erbay, Gurcan; 0000-0002-1706-8680; AAK-5370-2021Cancer is the one of the leading causes of death worldwide, and cancer incidence increases every year. The analysis of lesion margin is quite important to diagnose malignant and benign masses and to detect the presence and the stage of tumor invasion in case of cancer. Accordingly, the aim of the study is to visualize and quantify margin of lesions on radiological images by means of a digital computer. In this study, computed tomography (CT) images of liver have been employed for analysis because the liver has crucial tasks in our body and liver cancerrelated deaths is ranked as the forth among the cancer-related deaths. The proposed method consisted of four main steps: image cropping and smoothing, specification of target lesion, the boundary detection of target lesion, and visualization and quantification of margin. First, the images were converted to gray scale. The blank regions surrounding the liver in the CT images were removed before specification of target lesion, and further were smoothed with a bilateral filter. Next, the target region was specified roughly by drawing it manually. The boundary of lesion was more precisely determined with the active contour method employing the sketched borderline as the initial curve. Next, the properties of the target region: the centroid, major axis length, and the orientation values were computed. The intensities along a line passing through the center of the tumor were obtained for eighteen different rotation angles. A pulse model was fit to each of the intensity signal corresponding to a rotation. Then, the intensity change, margin sharpness and width were acquired from the pulse approximation associated to each rotation angle. The level difference provided the intensity change, the slope of edges gave the margin sharpness, and distance between the start and end points of the pulse edge represented margin width. Besides, the inner (core) and outer diameter with respect to angle were also displayed.Item Internal Comparison Standard for Abdominal Diffusion-Weighted Imaging(2017) Koc, Zafer; Erbay, Gurcan; Karadeli, Elif; 0000-0002-1706-8680; 0000-0002-0352-8818; 0000-0003-0987-1980; 27956463; AAK-5370-2021; AAK-5399-2021; S-8384-2016Background: Standards for abdominal diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC) measurements, and analysis are required for reproducibility. Purpose: To identify optimal internal comparison standards for DWI to normalize the measured ADC for increased accuracy of differentiating malignant and benign abdominal lesions. Material and Methods: We retrospectively studied 97 lesions (89 patients; age, 57 +/- 13 years) with histopathologically confirmed abdominal disease. Seven normal body parts/contents (normal parenchyma, spleen, kidney, gallbladder bile, paraspinal muscle, spinal cord, and cerebrospinal fluid [CSF]) were assessed as internal references for possible use as comparison standards. Three observers performed ADC measurements. Statistical analyses included interclass correlation coefficients (ICCs), Mann-Whitney and Kruskal-Wallis tests, and coefficient of variation (CV). ROC analyses were performed to assess diagnostic accuracy of lesion ADC and normalized ADC for differentiating lesions. Pathology results were the reference standard. Results: Mean and normalized ADCs were significantly lower for malignant lesions than for benign lesions (P< 0.001). ICC was excellent for all internal references. Gallbladder had the lowest CV. Receiver operating characteristic (ROC) analyses showed that normalized ADCs obtained using normal parenchyma were better than lesion ADCs for differentiating malignant and benign abdominal lesions (area under the curve [AUC], 0.808 and 0.756, respectively). The normalized ADCs obtained using CSF shows higher accuracy than lesion ADCs (0.80 and 0.76, respectively) for differentiating between malignant and benign abdominal lesions. Conclusion: The normal parenchyma from a lesion-detected organ can be used as an internal comparison standard for DWI. CSF can be used as a generalizable in plane reference standard.Item Can We Predict the Outcome of Varicocelectomy Based on the Duration of Venous Reflux?(2016) Goren, Mehmet Resit; Erbay, Gurcan; Ozer, Cevahir; Kayra, Mehmet Vehbi; Hasirci, Eray; https://orcid.org/0000-0002-2001-1386; https://orcid.org/0000-0002-1706-8680; https://orcid.org/0000-0001-6037-7991; https://orcid.org/0000-0002-7349-9952; https://orcid.org/0000-0002-4147-2966; 000373464600021; Y-6143-2019; AAK-5370-2021; AAK-8372-2021; AAI-7997-2021OBJECTIVE To investigate the outcome of varicocelectomy based on the duration of venous reflux (DVR) of the pampiniform plexus veins. MATERIALS AND METHODS In total, 138 patients with clinically palpable varicoceles were evaluated for DVR with color Doppler ultrasonography from May 2009 to August 2014. The DVR was defined as the DVR of a varicocele in the supine position during the Valsalva maneuver. Patients with bilateral, recurrent, or subclinical varicoceles; hormonal imbalances involving follicle-stimulating hormone, luteinizing hormone, or total testosterone; azoospermia; and intraoperative or postoperative complications were excluded. Of the 138 patients, 76 met the inclusion criteria. All patients were treated with subinguinal microscopic varicocelectomy. Restoration of all three semen parameters (concentration, motility, and morphology) to normal values 6 months postoperatively was considered to indicate treatment success. The patients were divided into those with a DVR of <4.5 seconds (Group 1) and >= 4.5 seconds (Group 2). RESULTS The mean age of the patients was 29.39 (+/- 6.03) years. No statistically significant relationship was found between the success rate and varicocele grade. The cutoff DVR value was calculated as 4.5 seconds using a receiver operating characteristics curve according to patients who underwent successful treatment. The success rates of Groups 1 and 2 were 40.0% and 88.2%, respectively (P = .0001). CONCLUSION The results of this analysis indicate that a DVR of >= 4.5 seconds predicts better outcomes of varicocelectomy. (C) 2016 Elsevier Inc.Item Utility of Diffusion-Weighted MRI to Detect Changes in Liver Diffusion in Benign and Malignant Distal Bile Duct Obstruction: The Influence of Choice of b-Values(2016) Karan, Belgin; Erbay, Gurcan; Koc, Zafer; Pourbagher, Aysin; Yildirim, Sedat; Agildere, Ahmet Muhtesem; 0000-0003-0987-1980; 0000-0002-5735-4315; 0000-0002-1706-8680; 0000-0003-4223-7017; 27592163; S-8384-2016; AAF-4610-2019; AAK-5370-2021; AAB-5802-2020Purpose: The study sought to evaluate the potential of diffusion-weighted magnetic resonance imaging to detect changes in liver diffusion in benign and malignant distal bile duct obstruction and to investigate the effect of the choice of b-values on apparent diffusion coefficient (ADC). Methods: Diffusion-weighted imaging was acquired with b-values of 200, 600, 800, and 1000 s/mm(2). ADC values were obtained in 4 segments of the liver. The mean ADC values of 16 patients with malignant distal bile duct obstruction, 14 patients with benign distal bile duct obstruction, and a control group of 16 healthy patients were compared. Results: Mean ADC values for 4 liver segments were lower in the malignant obstruction group than in the benign obstruction and control groups using b = 200 s/mm(2) (P < .05). Mean ADC values of the left lobe medial and lateral segments were lower in the malignant obstruction group than in the benign obstructive and control groups using b = 600 s/mm2 (P < .05). Mean ADC values of the right lobe posterior segment were lower in the malignant and benign obstruction groups than in the control group using b = 1000 s/mm(2) (P < .05). Using b = 800 s/mm(2), ADC values of all 4 liver segments in each group were not significantly different (P > .05). There were no correlations between the ADC values of liver segments and liver function tests. Conclusion: Measurement of ADC shows good potential for detecting changes in liver diffusion in patients with distal bile duct obstruction. Calculated ADC values were affected by the choice of b-values.Item Predicting Tumor Recurrence in Patients with Cervical Carcinoma Treated with Definitive Chemoradiotherapy: Value Of Quantitative Histogram Analysis On Diffusion-Weighted MR Images(2017) Erbay, Gurcan; Onal, Cem; Karadeli, Elif; Guler, Ozan C.; Arica, Sami; Koc, Zafer; https://orcid.org/0000-0002-1706-8680; https://orcid.org/0000-0002-0352-8818; https://orcid.org/0000-0001-6908-3412; https://orcid.org/0000-0003-0987-1980; 27445314; AAK-5370-2021; HOC-5611-2023; AAK-5399-2021; AAC-5654-2020; S-8384-2016Background: Further research is required for evaluating the use of ADC histogram analysis in more advanced stages of cervical cancer treated with definitive chemoradiotherapy (CRT). Purpose: To investigate the utility of apparent diffusion coefficient (ADC) histogram derived from diffusion-weighted magnetic resonance images in cervical cancer patients treated with definitive CRT. Material and Methods: The clinical and radiological data of 50 patients with histologically proven cervical squamous cell carcinoma treated with definitive CRT were retrospectively analyzed. The impact of clinicopathological factors and ADC histogram parameters on prognostic factors and treatment outcomes was assessed. Results: The mean and median ADC values for the cohort were 1.043 +/- 0.135 x 10(-3) mm(2)/s and 1.018 x 10(-3) mm(2)/s (range, 0.787-1.443 x 10(-3) mm(2)/s). The mean ADC was significantly lower for patients with advanced stage (>= IIB) or lymph node metastasis compared with patients with stage < IIB or no lymph node metastasis. The mean ADC, 75th percentile ADC (ADC75), 90th percentile ADC (ADC90), and 95th percentile ADC (ADC95) were significantly lower in patients with tumor recurrence compared with patients without recurrence. In multivariate analysis, tumor size, ADC75 and ADC95 were independent prognostic factors for both overall survival and disease-free survival. Conclusion: ADC histogram parameters could be markers for disease recurrence and for predicting survival outcomes. ADC75, ADC90, and ADC95 of the primary tumor were significant predictors of disease recurrence in cervical cancer patients treated with definitive CRT.Item Abdominal CT Findings in Patients with Primary Lymphoma Causing Small Bowel Obstruction(2017) Karadeli, Elif; Erbay, Gurcan; Parlakgumus, Alper; Yabanoglu, Hakan; 0000-0002-0352-8818; 0000-0002-1706-8680; 0000-0002-1161-3369; 29132484; AAK-5399-2021; AAK-5370-2021; AAJ-7865-2021The purpose of this study was to investigate retrospectively CT findings in patients with primary lymphoma causing small bowel obstruction. CT scans of 11 patients with small bowel lymphoma were separately analysed in terms of affected section of the small bowel, focality, wall thickness, pattern and degree of contrast enhancement, lymphadenopathy, organ involvement, perforation, and the presence of intraabdominal fluid. Eight patients had diffuse large B-cell lymphoma, and one patient each had marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT), T-cell lymphoma, and anaplastic T-cell lymphoma. Affected sections of the bowels involved were jejunum (n=5, 45.4%), ileum (n=2, 18.1%), and one case (9%) each of distal ileum, distal jejunum, distal jejunum and ileum, and distal jejunum and colon. Primary gastrointestinal (GI) lymphoma is an uncommon disease, that may lead to small bowel obstruction sometimes.