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Öğe 99mTc-dimercaptosuccinic acid scan versus MRI in pyelonephritis: a meta-analysis(Lippincott Williams & Wilkins, 2020) Sarikaya, Ismet; Albatineh, Ahmed N.; Sarikaya, AliPurpose Tc-99m-dimercaptosuccinic acid (DMSA) scan is the current gold standard in detecting parenchymal changes, particularly scarring, in pyelonephritis. Recently, magnetic resonance imaging (MRI) is gaining popularity in the diagnosis of pyelonephritis. The aim of this study is to perform a meta-analysis on studies directly comparing MRI to DMSA scan in patients with pyelonephritis. Materials Systematic searches of PUBMED and EMBASE databases were performed to extract studies comparing MRI and DMSA scan in patients with pyelonephritis. The relevance of articles was assessed by two authors according to predefined inclusion and exclusion criteria. The pooled estimates of the sensitivities of MRI and DMSA scan were computed using random-effects meta-analysis model following DerSimonian and Laird's method. Subgroup analysis and publication bias were performed. Results Seven studies were included (164 patients). Using random effect model, the pooled estimate of the sensitivities of MRI and DMSA scan were 0.62 (95%CI: 0.44 - 0.77) and 0.59 (95%CI: 0.48 - 0.70), respectively. The pooled estimates of sensitivities of MRI and DMSA scan for acute pyelonephritis were 0.73 (95%CI: 0.49- 0.89) and 0.66 (95%CI: 0.56 - 0.75), respectively, and for scar detection were 0.48 (95%CI: 0.31- 0.66), and 0.50 (95%CI: 0.30 - 0.71), respectively. Conclusion The overall sensitivities of MRI and DMSA scan were equivalent in detecting parenchymal changes in pyelonephritis. MRI and DMSA scan appeared to be equivalent to scar detection. In a small number of studies, MRI appeared to be better than the DMSA scan in acute pyelonephritis but this should be further studied in a larger number of patients.Öğe Anemia and PET imaging(Springer-Verlag Italia Srl, 2021) Sarikaya, Ismet; Baqer, Ali; Sarikaya, AliAim Anemia is a blood disorder characterized by reduced Hemoglobin concentration and/or red blood cells numbers. Most common causes of anemia are iron deficiency anemia and anemia of chronic disease (anemia of chronic inflammation), but there is a long list of conditions which cause anemia. Bone marrow (BM), spleen, and liver are the main organs but various other tissues are also involved depending on the type of anemia. In this article, we aimed to review the role of PET imaging in anemia. Methods Normal BM, typical and atypical forms of hematopoiesis, pathogenesis of various forms of anemia, and PET findings in anemia with various radiotracers such as F-18-fluorodeoxyglucose, F-18-fluorothymidine, Fe-52 compounds and F-18-sodium fluoride were reviewed. Results In cases with anemia PET can help in determining the extent of BM expansion, distribution of BM, detecting proliferative activity of BM and BM islands in acellular BM on iliac biopsy, guiding BM biopsies, detecting typical or atypical extramedullary hematopoiesis, acute BM infarctions and various other complications such as osteomyelitis, cerebral infarction and infarction in various other tissues. Anemia-related PET findings can mimic tumor/metastases. Conclusion PET imaging is useful for assessing various types of anemia. It is also important to be aware of anemia-related PET findings to avoid mistaking them for malignancy or metastases.Öğe Anemia and PET imaging (Aug, 10.1007/s40336-021-00442-z, 2021)(Springer-Verlag Italia Srl, 2021) Sarikaya, Ismet; Baqer, Ali; Sarikaya, Ali[Abstract Not Available]Öğe Assessing 18F-FDG Uptake in the Sentinel Lymph Node in Breast Cancer(Soc Nuclear Medicine Inc, 2019) Sarikaya, Ismet; Sarikaya, AliF-18-FDG PET/CT has limited value in early breast cancer. Sentinel lymph node (SLN) biopsy is the current procedure of choice to search for small metastatic deposits in the axillary lymph nodes in early breast cancer. In this retrospective study, we reevaluated F-18-FDG PET/CT images after locating the SLN on PET/CT with the help of SLN SPECT/CT images and assessed F-18-FDG uptake, particularly in the SLN. Our goal was to understand if combined evaluation of F-18-FDG PET/CT and SLN SPECT/CT could be useful for detecting early lymph node metastasis in the axilla. Methods: F-18-FDG PET/CT images of newly diagnosed breast cancer patients who also had SLN scintigraphy (SPECT/CT) and biopsy results were analyzed to assess F-18-FDG uptake in the SLN. The SLN seen on SPECT/CT images was located on PET/CT images, and its metabolic activity was assessed both visually and semiquantitatively using SUVmax. F-18-FDG PET results were compared with the histopathology result for the SLN. Results: Twenty patients among 130 met the inclusion criteria. SLN SPECT/CT images were helpful for locating the SLN on F-18-FDG PET/CT images in all 20 patients. Histopathologic analysis of the SLNs demonstrated metastasis in 7 patients and no metastasis in 13. There was mild (visible) F-18-FDG uptake in the SLN (SUVmax, 1.2-4.1; metastatic deposit size, 68 mm) in 6 of 7 patients with SLN metastasis (85.7%). There was no or only faint F-18-FDG uptake in the SLN (SUVmax, 1) in 9 of 13 patients with no SLN metastasis (69.2%). Receiver-operating-characteristic curve analysis indicated that the SUVmax cutoff for differentiating SLN-positive from -negative cases was 0.85 (sensitivity, 85.7%; specificity, 61.5%; area under the curve, 0.747; P < 0.05). Conclusion: Combined evaluation of F-18-FDG PET/CT and SPECT/CT images to assess F-18-FDG uptake, particularly in the SLN, is a new image analysis technique to detect early metastatic disease in the axillary lymph nodes in breast cancer. Although this technique does not currently seem feasible for use in routine practice, mainly because of the limitations of current PET/CT technology in detecting small tumors, it is an interesting image analysis technique to be aware of for possible future use.Öğe Assessing oral glucose and intravenous insulin loading protocol in18F-fluorodeoxyglucose positron emission tomography cardiac viability studies(Wolters Kluwer Medknow Publications, 2020) Sarikaya, Ismet; Sharma, Prem N.; Sarikaya, Ali; Elgazzar, Abdelhamid H.Oral glucose and intravenous insulin (G/I) loading protocols are commonly used in18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) cardiac viability studies. Although the amount of insulin to be given per blood glucose range has been well described in guidelines, the amount of glucose to be given is not detailed well. In this retrospective study, we aimed to assess if certain parameters, particularly the amount of glucose and insulin given, may affect18F-FDG uptake in the hibernating myocardium and also determine the problems with this protocol.18F-FDG PET cardiac viability study with G/I loading protocols was performed in 49 patients. Fasting blood glucose (FBG), amount of glucose given, blood glucose level after glucose load, amount of insulin given, and blood glucose level at the time of18F-FDG injection were recorded. Statistical analysis was performed to determine if there is any difference in the above values in PET viable and PET nonviable groups and also in subgroups assessing18F-FDG uptake also in normal myocardium. For G/I loading, we used our local protocol in 43 patients, and other protocols in six.18F-FDG PET showed viability in 31 patients, and it was negative for viability in 18. In 22 patients, mainly in PET viable group, there was varying degree of reduced18F-FDG uptake in normal myocardium. There was no significant difference in FBG, amount of glucose given, blood glucose level after glucose load, amount of insulin given, and blood glucose level at the time of18F-FDG injection in PET viable and PET nonviable groups and also in subgroups. The problems with G/I loading protocol included deciding on the amounts of glucose and insulin given, maximum amount of insulin to be given, handling diabetics, optimal time to measure blood glucose after insulin administration, and interpretation of findings in cases with diffusely reduced18F-FDG uptake. Further improvements in current guidelines are necessary to obtain images in optimal conditions for accurate results.Öğe Assessing PET Parameters in Oncologic 18F-FDG Studies(Soc Nuclear Medicine Inc, 2020) Sarikaya, Ismet; Sarikaya, AliPET imaging, particularly oncologic applications of F-18-FDG, has become a routine diagnostic study. To better describe malignancies, various PET parameters are used. In F-18-FDG PET studies, SUVmax is the most commonly used parameter to measure the metabolic activity of the tumor. In obese patients, SUV corrected by lean body mass (SUL), and in pediatric patients, SUV corrected by body surface area, are recommended. Metabolic tumor volume is an important parameter to determine the local and total tumor burden. Total lesion glycolysis (SUVmean x metabolic tumor volume) provides information about averages. Some treatment response assessment protocols recommend using the SUVpeak or SULpeak of the tumor. Tumor-to-liver ratio and tumor-to-blood-pool ratio are helpful when comparing studies for treatment response assessment. Dual-time-point PET imaging with retention index can help differentiate malignant from benign lesions and may help detect small lesions. Dynamic F-18-FDG PET imaging and quantitative analysis can measure the metabolic, phosphorylation, and dephosphorylation rates of lesions but are mainly used for research purposes. In this article, we will review the currently available PET parameters in F-18-FDG studies with their importance, uses, limitations, and reasons for erroneous results.Öğe Assessing the Correlation Between 68Ga-PSMA-11 Renal PET Parameters and Renal Function Tests(Soc Nuclear Medicine Inc, 2022) Schierz, Jan-Henning; Sarikaya, Ismet; Albatineh, Ahmed N.; Sarikaya, AliGa-68-prostate-specific membrane antigen (PSMA) ligands are used for prostate cancer but also show high renal cortical uptake. In this study, we aimed to assess whether there is any correlation between renal PSMA PET parameters and renal function tests using the images of prostate cancer patients. Methods: (68)GaPSMA-11 PET/CT images of the patients with prostate cancer were retrospectively evaluated. The following PET parameters were obtained: SUVmax, SUVmean, SUVmax corrected for lean body weight, SUVmean corrected for lean body weight, volume, lean body weight-corrected total lesion glycolysis (TLG(SUL)), and counts of both kidneys, as well as SUVmean of the liver, blood pool, and spleen. Total TLG(SUL), total volume, kidney-to-liver ratio, and kidney-to-blood pool ratio were calculated. Creatinine values were obtained, and glomerular filtration rate (GFR) was calculated using the Modification of Diet in Renal Disease formula. Statistical analysis was performed to understand whether there is a correlation between the above parameters and renal function tests. Results: Twenty-five patients were included in this study. GFR was significantly and positively correlated and creatinine was significantly and negatively correlated with the ratios of renal SUV to liver SUV and renal SUV to blood pool SUV. GFR was marginally positively correlated with renal SUVmean corrected for lean body weight, and creatinine was marginally negatively correlated with total TLG(SUL). Total renal parenchymal volume was significantly and directly (positively) associated with GFR and significantly and inversely (negatively) associated with creatinine. Conclusion: Renal Ga-68-PSMA uptake appears to be correlated with renal function tests. Our method of measuring approximate renal parenchymal volume on PET images appears to be reliable.Öğe Assessing the correlation between FDG PET findings of IDC breast carcinoma and histopathology of coexisting ductal carcinoma in-situ(Via Medica, 2022) Sarikaya, Ismet; Sarikaya, Ali; Albatineh, Ahmed N.; Tastekin, Ebru; Sezer, Yavuz AtakanBackground: Ductal carcinoma in-situ (DCIS) often coexists with invasive ductal carcinoma (IDC) of the breast. DCIS is consid-ered as a non-obligate precursor of IDC when both coexist. F-18-fluorodeoxyglucose positron emission tomography/computed tomography ([F-18]FDG PET/CT) imaging is commonly used in the staging and follow-up assessment of breast cancer. In this study, we aimed to assess if there is any correlation between primary tumor PET and histopathology findings and histopatho-logical features of the coexisting DCIS. Material and methods: FDG PET/CT images and histopathology results of the patients with newly diagnosed breast cancer (IDC) with coexisting DCIS were analyzed in this retrospective study. The grade and size of the primary tumor and histopathological features of the coexisting DCIS (nuclear grade and architectural pattern) were obtained from the postoperative histopathology results. Maximum standardized uptake values (SUV: SUVmax and SULmax) of the primary tumor normalized by weight and lean body mass were measured. Statistical analysis was performed to assess the correlation between various parameters of IDC and DCIS. Results: This study included sixty-two (62) patients with IDC-DCIS. Primary tumor grade was significantly correlated and associated with the nuclear grade of the coexisting DCIS (polychoric correlation r = 0.736, and Fisher exact test, PV < 0.001, respectively). Primary tumor SUV was not correlated with the nuclear grade and architectural pattern of the coexisting DCIS (polyserial correlation r = 0.172, PV = 0.155, and Point Bi-Serial correlation r = -0.009, PV = 0.955, respectively). Median primary tumor size was marginally significantly different among DCIS nuclear grades but it was not significantly different in comedo and non-comedo cases (Kruskal-Wallis test PV = 0.053, and Mann-Whitney U test PV = 0.890, respectively). Conclusions: Primary tumor grade is correlated with the nuclear grade of the coexisting DCIS. SUV of primary tumor does not seem to be correlated with the histopathological features of coexisting DCIS (nuclear grade and architectural pattern) but this may be further studied in a larger number of patients.Öğe Assessing the Effect of Various Blood Glucose Levels on 18F-FDG Activity in the Brain, Liver, and Blood Pool(Soc Nuclear Medicine Inc, 2019) Sarikaya, Ismet; Sarikaya, Ali; Sharma, PremStudies have extensively analyzed the effect of hyperglycemia on F-18-FDG uptake in normal tissues and tumors. In this study, we measured SUV in the brain, liver, and blood pool in normoglycemia, hyperglycemia, and hypoglycemia to understand the effect of blood glucose on F-18-FDG uptake and to develop a formula to correct SUV. Methods: Whole-body F-18-FDG PET/CT images of adults were selected for analysis. Brain SUVmax, blood-pool SUVmean, and liver SUVmean were measured at blood glucose ranges of 61-70, 71-80, 81-90, 91-100, 101-110, 111-120, 121-130, 131-140, 141-150, 151-160, 161-170, 171-180, 181-190, 191-200, and 201 mg/dL and above. At each blood glucose range, 10 PET images were analyzed (total, 150). The mean (+/- SD) SUV of the brain, liver, and blood pool at each blood glucose range was calculated, and blood glucose and SUV curves were generated. Because brain and tumors show a high expression of glucose transporters 1 and 3, we generated an SUV correction formula based on percentage reduction in brain SUVmax with increasing blood glucose level. Results: Mean brain SUVmax gradually decreased with increasing blood glucose level, starting after a level of 110 mg/dL. The approximate percentage reduction in brain SUV max was 20%, 35%, 50%, 60%, and 65% at blood glucose ranges of 111-120, 121-140, 141-160, 161-200, and 201 mg/dL and above, respectively. In the formula we generated, measured SUV max is multiplied by a reduction factor of 1.25, 1.5, 2, 2.5, and 2.8 for the blood glucose ranges of 111-120, 121-140, 141-160, 161-200, and 201 mg/dL and above, respectively, to correct SUV. Brain SUV max did not differ between hypoglycemic and normoglycemic patients (P > 0.05). SUVmean in the blood pool and liver was lower in hypoglycemic patients (P < 0.05) and did not differ between hyperglycemic (P > 0.05) and normoglycemic patients. Conclusion: Hyperglycemia gradually reduces brain F-18-FDG uptake, starting after a blood glucose level of 110 mg/dL. Hyperglycemia does not affect F-18-FDG activity in the liver or blood pool. Hypoglycemia does not seem to affect brain F-18-FDG uptake but appears to reduce liver and blood-pool activity. The simple formula we generated can be used to correct SUV in hyperglycemic adults in selected cases.Öğe Can 68Ga-DOTA Peptides Be Potential Radiotracers for PET Imaging of the Spleen?(Soc Nuclear Medicine Inc, 2018) Sarikaya, Ismet; Elgazzar, Abdelhamid H.; Sarikaya, Ali; Alnafisi, Naheel; Alenezi, SaudOn radionuclide somatostatin receptor imaging studies, the spleen shows high physiologic uptake. Reducing the intensity of the image settings helps to better assess the distribution of radiotracer in the spleen. In our routine studies, we incidentally recognized that Ga-68-DOTANOC PET provides higher-resolution splenic images than In-111-octreotide SPECT. Autoradiography and immunohistochemistry studies have shown that somatostatin receptors are located mainly in the red pulp of the spleen. The distribution of Ga-68-DOTANOC in the spleen appears to correlate with the distribution of red pulp. In this article, we present Ga-68-DOTANOC PET/CT spleen images of our patients.Öğe Current status of F-18-FDG PET brain imaging in patients with dementia(Soc Nuclear Medicine Inc, 2018) Sarikaya, Ismet; Sarikaya, Ali; Elgazzar, Abdelhamid H.F-18-FDG PET brain imaging is commonly used in the early detection and differential diagnosis of various subtypes of dementias.F- 18-FDG PET images are mainly evaluated visually, and semiquantitative analysis programs are also commonly used in many centers. However, visual and semiquantitative analysis carry certain limitations. Visual assessment is subjective and dependent on expertise. Commercially available semiquantitative analysis programs have certain limitations such as suboptimal selection of brain areas or erroneous uptake normalization procedures that may provide inaccurate results, and physicians reporting semiquantitative results should be aware of these. In this pictorial review article, we will discuss the current status of F-18-FDG PET brain imaging in patients with dementia and present figures and semiquantitative analysis results of various sub-types of dementias as well as certain artifacts seen on F-18-FDG PET brain imaging studies.Öğe Current Status of Radionuclide Renal Cortical Imaging in Pyelonephritis(Soc Nuclear Medicine Inc, 2019) Sarikaya, Ismet; Sarikaya, AliPyelonephritis is an infection of the kidneys that is seen more commonly in children than the adults. Tc-99(m)-dimercaptosuccinic acid (Tc-99m-DMSA) scanning is a radionuclide imaging study to detect renal scarring after acute pyelonephritis (a late Tc-99m-DMSA scan) and also helps to diagnose acute pyelonephritis in febrile urinary tract infections (an acute Tc-99m-DMSA scan). Planar imaging in multiple views (posterior and bilateral posterior oblique) is generally used. Pinhole imaging with a high-resolution-collimator magnification of each kidney allows detection of smaller cortical defects. SPECT is optional. SPECT/CT is not recommended in children because it has a higher radiation exposure than routine Tc-99m-DMSA scans. The main limitations of Tc-99m-DMSA scanning include a relatively long waiting time after radiotracer injection, a long acquisition time, and a high radiation dose, which is particularly important in repeated studies on children and with the limited spatial resolution of y-cameras. Tc-99m-glucoheptonate is an alternative radiotracer when (99m)TcDMSA is not available. Radiotracers for dynamic renal functional imaging can grossly assess the renal cortex in the first few minutes of imaging. Ga-68-prostate-specific membrane antigen ligand (Ga-68-PSMA ligand) PET has the ability to provide images of normal renal cortex and demonstrate renal cortical defects from cysts. In this article, we assess the current status of renal cortical imaging and present Ga-68-PSMA ligand PET images. Ga-68-PSMA ligand provides excellent renal cortical images, and studies should be done to compare Ga-68-PSMA ligand PET with (99)mTc-DMSA scanning in renal diseases, particularly in pyelonephritis.Öğe F-18 fluoride uptake in primary breast cancer(Springer, 2018) Sarikaya, Ismet; Sharma, Prem; Sarikaya, AliObjectiveBone-specific radiotracers are known to accumulate in breast lesions. Tc-99m diphosphonates have been widely studied in differentiating breast lesions. In this retrospective study, we aimed to assess the uptake of the bone-specific PET radiotracer, F-18 fluoride (NaF), in primary breast cancers to determine its sensitivity and to identify any differences in NaF uptake between calcified and non-calcified tumors, histological subtypes, and patients with or without axillary lymphadenopathy.MethodsNaF positron emission tomography/computed tomography (PET/CT) images of 69 newly diagnosed breast cancer patients were reviewed. F-18 fluoride uptake as maximum standardized uptake value (NaF SUVmax) was measured in the primary tumor, enlarged axillary lymph nodes and contralateral normal/non-tumoral breast tissue. Low-dose CT images were reviewed to locate the primary tumor and grossly assess its calcification and check for ipsilateral axillary lymphadenopathy. Whole body NaF PET/CT images were reviewed to search for bone metastases. Eighteen patients also underwent F-18 fluorodeoxyglucose (FDG) PET/CT study.ResultsThe primary breast tumor was clearly seen as focal or diffuse uptake on NaF PET images in 27 of 69 patients (39%) (mean NaF SUVmax: 2.01.0). In the rest, there was only mild bilateral diffuse breast uptake. When analyzing images per histological subtype (42 patients, 43 tumors), 14 of 31 invasive ductal carcinomas (IDC) (45%) and 3 of 4 ductal carcinoma in situ (DCIS) were visible on PET. Five invasive lobular carcinomas, 2 invasive mammary carcinomas, and 1 mucinous carcinoma were not visible on PET. Mean NaF SUVmax of contralateral normal/non-tumoral breast tissue was 1.0 +/- 0.4. There was no significant difference in mean NaF SUVmax of primary tumor in cases with and without calcification or with and without axillary lymphadenopathy (p 0.892 and 0.957). There was no correlation between NaF SUVmax and FDG SUVmax values of the primary tumors (r 0.072, p 0.797, Pearson correlation).ConclusionNaF PET has relatively low sensitivity in detecting breast cancer. However, abnormal breast uptake on NaF PET requires further evaluation. F-18 fluoride uptake in the primary breast tumor does not seem to be correlated with axillary lymphadenopathy (metastasis potential), gross tumor calcification or metabolic activity of the tumor.Öğe Immune Checkpoint Inhibitor-Related Adverse Effects and 18F-FDG PET/CT Findings(Soc Nuclear Medicine Inc, 2021) Schierz, Jan-Henning; Sarikaya, Ismet; Wollina, Uwe; Unger, Leonore; Sarikaya, AliImmune checkpoint inhibitor (ICI) treatments activate T cells against tumors. Activated T cells attack not only the tumor but also healthy cells, causing an autoimmune reaction in various tissues. These immune-related adverse effects (IRAEs) cause F-18-FDG uptake in various tissues due to inflammation. It is important to recognize and report these findings on F-18-FDG PET/CT studies. F-18-FDG PET helps to determine the presence, location, and severity of IRAEs. In severe cases, ICI treatments are interrupted or suspended and antiinflammatory treatments are started. F-18-FDG uptake due to IRAEs may mimic metastases or disease progression. Their presence may also help in predicting response to treatment and have prognostic implications. In this review article, we provide basic information about ICI treatments, IRAEs, and F-18-FDG PET/CT findings.Öğe Liver: glucose metabolism and 18F-fluorodeoxyglucose PET findings in normal parenchyma and diseases(E-Century Publishing Corp, 2021) Sarikaya, Ismet; Schierz, Jan-Henning; Sarikaya, AliLiver has a complex and unique energy metabolism and plays a major role in glucose homeostasis. Liver is the main control center for glycogenesis, glycogenolysis, glycolysis and gluconeogenesis which are essential to provide energy for other tissues. Liver meets its own energy need from various sources which is mainly glucose in the fed state and fatty acids in the fasting state. In this review article, we will mainly describe the glucose metabolism of the liver, effect of various factors on 18F-fluorodeoxyglucose (FDG) activity/uptake in the normal liver and 18F-FDG positron emission tomography (PET) uptake patterns in various malignant and benign liver pathologies. Brief information on metabolomics profiling analyses in liver disorders will also be be provided.Öğe Normal bone and soft tissue distribution of fluorine-18-sodium fluoride and artifacts on 18F-NaF PET/CT bone scan: a pictorial review(Lippincott Williams & Wilkins, 2017) Sarikaya, Ismet; Elgazzar, Abdelhamid H.; Sarikaya, Ali; Alfeeli, MahmoudFluorine-18-sodium fluoride (F-18-NaF) PET/CT is a relatively new and high-resolution bone imaging modality. Since the use of F-18-NaF PET/CT has been increasing, it is important to accurately assess the images and be aware of normal distribution and major artifacts. In this pictorial review article, we will describe the normal uptake patterns of F-18-NaF in the bone tissues, particularly in complex structures, as well as its physiologic soft tissue distribution and certain artifacts seen on F-18-NaF PET/CT images. Copyright (C) 2017 Wolters Kluwer Health, Inc. All rights reserved.Öğe PET/CT Image Artifacts Caused by the Arms(Soc Nuclear Medicine Inc, 2021) Sarikaya, Ismet; Sarikaya, AliPET/CT images are usually obtained in the arms-up position in patients with no head and neck pathology and in the arms-down position to image the head and neck area. The arms usually cause artifacts regardless of up or down positioning. These artifacts include beam hardening, scatter, truncation, and cold areas (cold artifacts) in obese or large patients; motion artifacts; implanted-metal-object artifacts; and artifacts related to radiotracer extravasation at the injection site. In this review article, we will discuss the mechanisms of these artifacts and suggest solutions to reduce or eliminate them, such as reviewing the non-attenuation-corrected PET images, performing extended-field-of-view reconstruction, not applying scatter correction, and using software to correct beam-hardening, scatter, and truncation artifacts. We will present various PET/CT images before and after corrections for such artifacts.Öğe Prognostic significance of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography-derived metabolic parameters in surgically resected clinical-N0 nonsmall cell lung cancer(Lippincott Williams & Wilkins, 2018) Aktas, Gul E.; Karamustafaoglu, Yekta A.; Balta, Cenk; Sut, Necdet; Sarikaya, Ismet; Sarikaya, AliObjective Our aim was to assess the significance of metabolic positron emission tomography (PET) parameters for the prediction of occult mediastinal lymph node metastasis (OLM) and recurrence in patients with clinical-N0 nonsmall cell lung cancer (NSCLC) after surgical resection and lymph node dissection. Materials and methods We evaluated 98 patients with NSCLC [52 adenocarcinoma (ADC), 46 squamous cell carcinoma (SQCC)] who had undergone initial/preoperative fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (F-18-FDG PET/CT). Eligibility criteria for participation were clinically staged as N0 and no FDG uptake in mediastinal lymph nodes on preoperative PET/CT. Clinicopathological characteristics and the diagnosis of recurrence were obtained by reviewing the hospital records. Metabolic parameters [maximum standardized uptake value, mean standardized uptake value, metabolic tumor volume (MTV), total lesion glycolysis] were determined on F-18-FDG PET/CT images. The association of metabolic parameters with OLM and recurrence was assessed. Results OLM was found in 26 (26.53%) patients. T-stage, central location, and lymphovascular invasion were associated with OLM (respectively, P = 0.007, 0.011, <0.001). None of the metabolic parameters was associated with OLM. Metabolic parameters of the tumor were significantly higher in patients with recurrence when the cohort was evaluated as a whole (P = 0.002, 0.005, 0.016, and 0.004, respectively). In particular, there was a significant association between recurrence and tumor size, grade, stage, MTV (P < 0.001), and TLG (P < 0.001) in ADC. This association was not found in SQCC. Multivariate analysis showed that MTV was an independent prognostic factor for recurrence and associated with disease-free survival. Conclusion Metabolic parameters of the primary tumor on preoperative 18F-FDG PET/CT could not predict OLM in patients with clinical-N0 NSCLC. MTV was an independent risk factor for recurrence in ADC, but not in SQCC. Copyright (C) 2018 Wolters Kluwer Health, Inc. All rights reserved.Öğe Renal Cortical 68Ga-PSMA-11 PET and 99mTc-DMSA Images(Soc Nuclear Medicine Inc, 2021) Sarikaya, Ismet; Alqallaf, Ahmed; Sarikaya, AliGa-68-prostate-specific membrane antigen (PSMA) ligands are novel PET radiotracers for prostate cancer. These radiotracers also localize in the normal renal cortex to a high degree and can demonstrate parenchymal defects. We recently started a prospective research study to compare Ga-68-PSMA-11 PET/CT with Tc-99m-dimercaptosuccinic acid (DMSA) scan in adults with pyelonephritis. Here, we present a side-by-side comparison of renal cortical PSMA PET/CT and DMSA images of an adult patient with chronic recurring pyelonephritis. Methods: Our prospective study was approved by the Ethical Committees. DMSA images (multiple planar and SPECT) were obtained 3 h after intravenous injection of 111 MBq (3 mCi) of Tc-99m-DMSA. On a separate day, we obtained PET/CT images of the kidneys 60 min after intravenous injection of 74 MBq (2 mCi) of Ga-68-PSMA-11 after the patient provided written informed consent. Results: The patient was a 46-y-old woman with history of chronic recurring pyelonephritis. Both DMSA scan and PSMA PET/CT demonstrated slight cortical thinning with mildly reduced uptake in the upper pole of the right kidney, with no significant cortical defects. There was an excellent distribution of activity in the renal cortex and better image resolution with PSMA PET than with DMSA scan. Non-attenuation-corrected PSMA PET images also showed the same findings, with reasonable image quality. Conclusion: In our first case, Ga-68-PSMA-11 PET imaging provided promising results in an adult patient with pyelonephritis. The results of our prospective study on a larger number of adult patients will provide a more accurate comparison of Ga-68-PSMA-11 PET to Tc-99m-DMSA scanning in pyelonephritis.Öğe Renal Cortical Scarring: 68Ga-PSMA-11 PET Versus 99mTc-DMSA Scanning in a Case of Pyelonephritis(Soc Nuclear Medicine Inc, 2022) Sarikaya, Ismet; Alqallaf, Ahmed; Sarikaya, Ali; Baqer, Ali; Kazem, NafisaWe previously reported the Ga-68-labeled prostate-specific membrane antigen (PSMA)-11 and Tc-99m-dimercaptosuccinic acid (DMSA) images of the first patient in our prospective research comparing renal Ga-68-PSMA-11 PET with Tc-99m-DMSA scanning in adults with pyelonephritis. Here, we present the renal cortical Ga-68-PSMA-11 PET and Tc-99m-DMSA images of our second patient, who had chronic recurring pyelonephritis and demonstrated renal parenchymal defects secondary to scarring in the kidney.
