Tıp Fakültesi / Faculty of Medicine
Permanent URI for this collectionhttps://hdl.handle.net/11727/1403
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Item PET Studies in Epilepsy(2015) Sarikaya, Ismet; 0000-0002-1087-580X; 26550535; G-7881-2015Various PET studies, such as measurements of glucose, serotonin and oxygen metabolism, cerebral blood flow and receptor bindings are availabe for epilepsy. (18)Fluoro-2-deoxyglucose (F-18-FDG) PET imaging of brain glucose metabolism is a well established and widely available technique. Studies have demonstrated that the sensitivity of interictal FDG-PET is higher than interictal SPECT and similar to ictal SPECT for the lateralization and localization of epileptogenic foci in presurgical patients refractory to medical treatments who have noncontributory EEG and MRI. In addition to localizing epileptogenic focus, FDG-PET provide additional important information on the functional status of the rest of the brain. The main limitation of interictal FDG-PET is that it cannot precisely define the surgical margin as the area of hypometabolism usually extends beyond the epileptogenic zone. Various neurotransmitters (GABA, glutamate, opiates, serotonin, dopamine, acethylcholine, and adenosine) and receptor subtypes are involved in epilepsy. PET receptor imaging studies performed in limited centers help to understand the role of neurotransmitters in epileptogenesis, identify epileptic foci and investigate new treatment approaches. PET receptor imaging studies have demonstrated reduced C-11-flumazenil (GABAA-cBDZ) and F-18-MPPF (5-HT1A serotonin) and increased C-11-cerfentanil (mu opiate) and C-11-MeNTI (delta opiate) bindings in the area of seizure. 11C-flumazenil has been reported to be more sensitive than FDG-PET for identifying epileptic foci. The area of abnormality on GABAA-cBDZ and opiate receptor images is usually smaller and more circumscribed than the area of hypometabolism on FDG images. Studies have demonstrated that C-11-alpha-methyl-L-tryptophan PET (to study synthesis of serotonin) can detect the epileptic focus within malformations of cortical development and helps in differentiating epileptogenic from non-epileptogenic tubers in patients with tuberous sclerosis complex. O-15-H2O PET was reported to have a similar sensitivity to FDG-PET in detecting epileptic foci.Item Textiloma Mimicking Superior Sulcus Tumor: Positron Emission Tomography/Computed Tomography Findings of a Pseudotumor(2014) Findikcioglu, Alper; Karadayi, Sule; Kilic, Dalokay; Hatipoglu, Ahmet; 23436618; AFT-2303-2022; H-7700-2019We present an interesting case report of a 52-year-old man with a superior sulcus tumor. To evaluate the suspicious left lung tumor, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was used. Increased FDG level was indicative of a malignant tumor. Left thoracotomy revealed a textiloma retained during cardiac surgery.Item PET Imaging in Neurology: Alzheimer's and Parkinson's Diseases(2015) Sarikaya, Ismet; 0000-0002-1087-580X; 25920047; G-7881-2015PET studies play an important role in the early detection of Alzheimer's and Parkinson's diseases (AD and PD). Fluorine-18 fluorodeoxyglucose (F-18-FDG) PET imaging of regional cerebral glucose metabolism and PET amyloid imaging are the two major PET studies for AD. F-18-FDG PET is highly sensitive for the early diagnosis of AD, in predicting conversion from mild cognitive impairment to AD, and in differentiating AD from other dementias. PET amyloid imaging is positive in the majority of patients with AD. Negative amyloid PET reduces the likelihood of AD. The main limitations of PET amyloid imaging is its high positivity in the normal elderly population and in other medical conditions with amyloid pathologies. Various PET tracers are available to assess motor and cognitive dysfunctions in PD. PET tracers targeting presynaptic dopaminergic function (F-18-DOPA, radiolabeled PET tracers assessing the availability of dopamine transporters and vesicular monoamine transporters) and postsynaptic dopamine receptors are used to assess motor dysfunction in PD. PET tracers, particularly dopamine transporters, are highly sensitive in the early diagnosis of PD. Uptake of PET tracers in the striatum is inversely correlated with disease severity. PET is valuable in differentiating PD from other movement disorders. PET studies, particularly F-18-FDG PET, help to evaluate cortical metabolism in PD patients with cognitive dysfunction and dementia.Item Predictors Determining the Status of Axilla in Breast Cancer: Where is PET/CT on That?(2015) Aytac, Huseyin Ozgur; Colacoglu, Tamer; Nursal, Gul Nihal; Nursal, Tarik Zafer; Bolat, Filiz Aka; Yabanoglu, Hakan; Yildirim, Sedat; Moray, Gokhan; 0000-0002-3583-9282; 0000-0003-0268-8999; 0000-0003-2498-7287; 0000-0002-5735-4315; 0000-0002-5302-4386; 0000-0002-3462-7632; 0000-0002-1161-3369; 0000-0003-2031-7374; 26537078; AAJ-7913-2021; AAK-2011-2021; AAE-1041-2021; AAF-4610-2019; R-3735-2016; IQV-1169-2023; AAJ-8097-2021; AAJ-7865-2021; HJZ-1654-2023Purpose: 18 F-FDG PET/CT has an acceptable specificity but a low sensitivity on the prediction of axillary lymph node (ALN) metastasis in breast cancer. We analyzed the factors that could possibly affect this prediction. Methods: The records of 270 patients with T1-2 invasive breast cancer who underwent surgery, 116 of whom had been evaluated by preoperative 18 F-FDG PET/CT were reviewed. Prediction of ALN status by PET/CT according to tumor stage, estrogen receptor (ER), progesterone receptor (PgR) and HER2 status, histology, age and sentinel node properties was assessed. Results: ALN metastasis was present in 62 of 131 T1 (43.7%) and 106 of 142 T2 tumors (74.6%), 20 of 46 (43.5%) ER(-) and 146 of 222 (65.8%) ER(+) tumors, 38 of 71 (53.5%) PgR(-) and 127 of 200 (63.5%) PgR(+) tumors. On multivariate analysis only the tumor size (>2 cm) independently correlated with ALN metastasis (Odds ratio/OR=3.1). None of the other parameters had statistical significance in terms of ALN prediction on FDG-PET/CT. Conclusion: Though T2 tumors showed increased tendency to metastasize to the axilla, prediction of ALN metastasis in preoperative FDG-PET/CT was not associated with any of the predictive factors.Item Prognostic Value of Metabolic Tumor Volume and Total Lesion Glycolysis in Esophageal Carcinoma Patients Treated with Definitive Chemoradiotherapy(2018) Yildirim, Berna A.; Torun, Nese; Guler, Ozan C.; Onal, Cem; 0000-0001-6908-3412; 0000-0001-6661-4185; 0000-0002-2742-9021; 0000-0002-5597-676X; 29668513; AAC-5654-2020; V-5717-2017; D-5195-2014; AAE-2718-2021PurposeThe aim of this study was to evaluate the prognostic importance metabolic tumor volume (MTV), total lesion glycolysis (TLG), and standardized uptake value (SUV) in patients with esophageal cancer treated with definitive chemoradiotherapy.Patients and methodsSeventy-two esophageal cancer patients treated with definitive chemoradiotherapy [57 (79%) patients] or definitive radiotherapy [15 (21%) patients] were retrospectively analyzed. The regions equal to or greater than SUV of 2.5 were selected to delineate MTV and TLG was calculated by multiplying the mean SUV by the MTV of the primary lesions. The overall survival (OS) and disease-free survival (DFS) were evaluated for all patients and also patients with squamous cell carcinoma.ResultsThe median survival time was 13.4 months (range: 1.8-119.3 months) for all patients. Maximum SUV, mean SUV, MTV, and TLG values were significantly higher in patients with extensive T-stage (T3-T4) compared with patients with T1-T2 disease. Patients with regional lymph node metastasis had significantly higher MTV and TLG values compared with patients with no lymph node metastasis. On multivariate analysis, MTV, TLG, presence of lymph node metastasis, and lack of concurrent chemotherapy were negative significant prognostic factors for OS and DFS for the entire cohort and for patients with squamous cell carcinoma esophageal cancer.ConclusionMetabolic volumes (MTV and TLG), regional lymph node metastasis, and concurrent chemotherapy are major prognostic factors for DFS and OS in patients with esophageal carcinoma. In addition, MTV and TLG are important in predicting nodal metastasis, and together with metabolic volumes, SUV are associated significantly with local tumor invasion.Item Prognostic Value of Metabolic Response Measured by F-18-FDG-PET in Oesophageal Cancer Patients Treated with Definitive Chemoradiotherapy(2016) Onal, Cem; Torun, Nese; Guler, Ozan C.; Yildirim, Berna A.; 0000-0002-2742-9021; 0000-0001-6661-4185; 0000-0002-5597-676X; 0000-0001-6908-3412; 27612030; D-5195-2014; V-5717-2017; AAE-2718-2021; AAC-5654-2020BackgroundThis study aimed to assess the efficacy of fluorine-18 fluorodeoxyglucose (F-18-FDG)-PET for predicting overall survival (OS) and disease-free survival (DFS) in oesophageal cancer patients after definitive chemoradiotherapy (CRT) and prognostic importance of metabolic response detected by post-treatment PET at least 3 months after completing CRT.Materials and methodsData from 58 oesophageal cancer patients receiving definitive CRT were retrospectively analysed. Post-treatment F-18-FDG-PET was delivered at a median of 3.2 (range, 3.0-6.4) months after CRT. The impact of metabolic response determined by post-treatment F-18-FDG-PET, maximum post-treatment standardized uptake value (SUVmax) and percent SUV change (pretreatment to post-treatment) on survival was analysed.ResultsThe median follow-up was 19.7 (range, 4.2-91.9) months for all patients and 28.2 (range, 13.7-91.9) months for survivors. The mean pretreatment and post-treatment SUVmax and the median percent SUV decrease were 18.66.4, 6.2 +/- 4.6 and -73% (+13 to -100%). Pretreatment SUVmax was higher in patients with locoregional or distant failure than in those without (P<0.001). Pretreatment SUVmax was lower in patients with a complete response (CR) than in those without a CR (P=0.006). Two-year OS and DFS were higher in patients with CR compared with those without CR (P<0.001). CR rates detected by post-treatment F-18-FDG-PET were lower in patients with lymph node metastases or longer tumours than in those with shorter tumours or no metastases. During multivariate analysis, post-treatment SUVmax was a significant predictor for OS, and post-treatment SUVmax, percent SUV decrease and tumour length were significant prognostic factors for DFS.ConclusionMetabolic response assessed by post-treatment F-18-FDG-PET at least 3 months after CRT showed that post-treatment SUVmax and percent SUV change were important survival predictors.Item Efficacy of positron emission tomography and computed tomography in clinical staging of cutaneous malignant melanoma(2020) Yilmaz, Harun; Orhan, Erkan; Sahin, Ertan; Olguner, Anil A.; Arpaci, Enver; 32160381Accurate staging is very important for determining the prognosis and appropriate treatment for malignant melanoma (MM). The aim of this study is to determine the effectiveness of positron emission tomography and computed tomography (PET/CT) imaging in staging MM. Patients diagnosed with MM who then underwent PET/CT metastasis before treatment were assessed retrospectively. For each patient, the following variables were recorded: Breslow thickness, Clark's level, number of mitoses, the presence of ulceration detected in the pathology report, and the presence of lymph nodes and/or distant metastases detected by PET/CT. The pathology and PET/CT reports of 139 patients (79 female and 60 male) were retrospectively evaluated for staging after MM diagnosis. Patients with a Breslow thickness greater than 3.4 mm and Clark's level of 4 to 5 were found to be statistically significantly higher with regional lymph node metastasis after PET/CT scans. Patients with Breslow thickness greater than 2.85 mm and Clark's level of 4 to 5 were found to be statistically significantly higher with distant metastasis after PET/CT scan. The results of our study suggest that PET/CT imaging for metastasis scanning, starting with T2 patients, may be used in MM staging to reduce the need for sentinel lymph node (SLN) biopsy and lymph node dissection.Item Primary Hepatocellular Carcinoma With Intense Ga-68-PSMA Uptake But Slight F-18-FDG Uptake on PET/CT Imaging(2020) Erhamamci, Seval; Aslan, Nesrin; 31977478Ga-68-PSMA PET/CT imaging is an emerging imaging modality in prostate cancer. PSMA expression is also reported for nonprostate malignancies, including primary hepatocellular carcinoma. Herein, we present a case of a 74-year-ald man with recently diagnosed hepatocellular carcinoma who was referred for F-18-FDG PET/CT imaging for initial staging. The patient underwent F-18-FDG PET/CT as part of staging procedure; he also underwent Ga-68-PSMA PET/CT. PET/CT images revealed only slight F-18-FDG uptake in the liver lesion, but intense Ga-68-PSMA uptake, without any metastatic lesion seen elsewhere in the body.Item Retroperitoneal paraganglioma presenting as right-sided varicocele: case report(2016) Ates, Nihat; Yuksel, Mustafa; Yilmaz, Serdar; Habibi, Mani; Ipekci, Tumay; 0000-0002-2755-0526; 26997533; AAB-2986-2020Varicocele, the most important identifiable pathological cause of male infertility, is rarely observed on the right side. In isolated cases of right-sided varicocele, the presence of retroperitoneal masses compressing the inferior vena cava should be considered by further investigation. The retroperitoneal masses that are detected tend to grow rapidly due to their location and may be very large at the time of diagnosis. Soft tissue sarcomas are the most common cause of retroperitoneal masses, while paragangliomas are rare causes. Retroperitoneal paragangliomas should be diagnosed via detection of symptoms caused by hormonal activity, observation of the compression effect of the mass, or incidentally during imaging studies. SIMILAR CASES PUBLISHED: This study presents the first case of retroperitoneal paraganglioma in a 41-year old man as isolated right-sided varicocele that has been described in the published reports.