Publications by authors named "Mehmet Reyhan"

54 Publications

Clinical parameters and nomograms for predicting lymph node metastasis detected with Ga-PSMA-PET/CT in prostate cancer patients candidate to definitive radiotherapy.

Prostate 2021 May 5. Epub 2021 May 5.

Department of Radiation Oncology, Faculty of Medicine, Hacettepe University, Ankara, Turkey.

Background: Defining the extent of disease spread with imaging modalities is crucial for therapeutic decision-making and definition of treatment. This study aimed to investigate whether clinical parameters and nomograms predict prostate-specific membrane antigen (PSMA)-positive lymph nodes in treatment-naïve nonmetastatic prostate cancer (PC) patients.

Materials And Methods: The clinical data of 443 PC patients (83.3% high-risk and 16.7% intermediate-risk) were retrospectively analyzed. Receiver operating characteristic (ROC) curves with areas under the curve (AUC) were generated to evaluate the accuracy of clinical parameters (prostate-specific antigen [PSA], T stage, Gleason score [GS], International Society of Urological Pathology [ISUP] grade) and nomograms (Roach formula [RF], Yale formula [YF], and a new formula [NF]) in predicting lymph node metastasis. The AUCs of the various parameters and clinical nomograms were compared using ROC and precision-recall (PR) curves.

Results: A total of 288 lymph node metastases were identified in 121 patients (27.3%) using Ga-PSMA-11-positron emission tomography (PET)/computed tomography (CT). Most PSMA-avid lymph node metastases occurred in external or internal iliac lymph nodes (142; 49.3%). Clinical T stage, PSA, GS, and ISUP grade were significantly associated with PSMA-positive lymph nodes according to univariate logistic regression analysis. The PSMA-positive lymph nodes were more frequently detected in patients with PSA >20 ng/ml, GS ≥7 or high risk disease compared to their counterparts. The clinical T stage, serum PSA level, GS, and ISUP grade showed similar accuracy in predicting PSMA-positive metastasis, with AUC values ranging from 0.675 to 0.704. The median risks for PSMA-positive lymph nodes according to the RF, YF, and NF were 31.3% (range: 12.3%-100%), 22.3% (range: 4.7%-100%), and 40.5% (range: 12.3%-100%), respectively. The AUC values generated from ROC and PR curve analyses were similar for all clinical nomograms, although the RF and YF had higher accuracy compared to NF.

Conclusion: The clinical T stage, PSA, GS, and ISUP grade are independent predictors of PSMA-positive lymph nodes. The RF and YF can be used to identify patients who can benefit from Ga-PSMA-11 PET/CT for the detection of lymph node metastasis. Together with nomograms, Ga-PSMA-11 PET/CT images help to localize PSMA-positive lymph node metastases and can thus assist in surgery and radiotherapy planning.
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http://dx.doi.org/10.1002/pros.24142DOI Listing
May 2021

The use of 18F-FDG positron emission tomography to detect mediastinal lymph nodes in metastatic breast cancer.

Breast 2020 Dec 26;54:197-202. Epub 2020 Oct 26.

Baskent University Faculty of Medicine, Adana Dr Turgut Noyan Research and Treatment Center, Department of Nuclear Medicine, Adana, Turkey.

Background: To assess the predictive value of F-fluorodeoxyglucose positron-emission tomography (FDG-PET/CT) in detecting mediastinal lymph node metastasis with histopathologic verification in breast cancer (BC) patients.

Materials And Methods: Between February 2012 and October 2019, 37 BC patients who underwent histopathological verification for FDG-PET positive mediastinal lymph nodes were retrospectively analyzed. Nine patients (24%) were screened before beginning treatment, while 27 (76%) were screened at the time of disease progression, an average of 39 months after completion of initial treatment.

Results: The histopathologic diagnosis revealed lymph node metastasis from BC in 15 patients (40%) and benign disease in 22 patients (60%). The standardized uptake value (SUV) of mediastinal lymph nodes was significantly higher in patients with lymph node metastasis compared to those with benign histology (9.0 ± 3.5 vs. 5.9 ± 2.4; P = 0.007). The cut-off value of SUV after the ROC curve analysis for pathological lymph node metastasis was 6.4. Two of the 15 patients with mediastinal SUV ≤ 6.4 and 13 of the 22 patients with SUV > 6.4 had lymph node metastasis. Age and pathological findings were prognostic factors for overall survival in univariate analysis. The treatment decision was changed in 19 patients (51%) after mediastinoscopic evaluation of the entire cohort.

Conclusions: This is the first study to support the need for pathologic confirmation of a positive PET/CT result following evaluation of mediastinal lymph nodes for staging BC, either at initial diagnosis or at the time of progression. Treatment decisions were consequently altered for nearly half of the patients.
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http://dx.doi.org/10.1016/j.breast.2020.10.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7593617PMC
December 2020

Retrospective correlation of ga-psma uptake with clinical parameters in prostate cancer patients undergoing definitive radiotherapy.

Ann Nucl Med 2020 Jun 27;34(6):388-396. Epub 2020 Mar 27.

Faculty of Medicine, Department of Nuclear Medicine, Adana Dr Turgut Noyan Research and Treatment Center, Başkent University, Adana, Turkey.

Objective: The aim of the study is to investigate the correlation between the intensity of prostate-specific membrane antigen (PSMA) uptake in primary tumor and clinico-pathological characteristics of non-metastatic prostate cancer patients treated with definitive radiotherapy (RT).

Methods: Using the clinical data of 201 prostate cancer patients who were referred for  Ga-PSMA-positron emission tomography (PET/CT) for staging and RT planning, we analyzed the correlations among intermediate- or high-risk disease based on Gleason score (GS), prostate-specific antigen (PSA) level, D'Amico risk group classification, and maximum standardized uptake (SUV) of primary tumor.

Results: Primary tumor was visualized via  Ga-PSMA-PET/CT scan in 192 patients (95.5%). The median SUV of primary tumor and metastatic lymph node were 13.2 (range 3.3-83.7) and 11.4 (range 3.6-64.5), respectively. A significant moderate correlation was observed between PSA level and median tumor SUV as measured by  Ga-PSMA-PET/CT (Spearman = 0.425; p < 0.001). Patients with serum PSA > 10 ng/mL, GS > 7, D'Amico high-risk group classification, and pelvic lymph node metastasis had significantly higher tracer uptake in primary tumor than their counterparts. The median SUV of primary tumor was highest in patients with GS 9. The primary tumor detection rates of  Ga-PSMA-PET/CT were 83%, 92%, and 99% for patients with serum PSA ≤ 5.0 ng/mL (14 patients, 7%), PSA 5.1-10.0 ng/mL (45 patients, 22%), and PSA > 10 ng/mL (142 patients, 71%), respectively.

Conclusions: We demonstrated a correlation between prostate tumor characteristics and PSMA tracer uptake. Patients with serum PSA > 10 ng/mL, GS > 7, D'Amico high-risk group classification, and pelvic lymph node metastasis had significantly higher SUV than their counterparts. In addition, the primary tumor detection rate was higher in patients with serum PSA > 10 ng/mL and GS > 7.
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http://dx.doi.org/10.1007/s12149-020-01462-xDOI Listing
June 2020

The effect of androgen deprivation therapy on Ga-PSMA tracer uptake in non-metastatic prostate cancer patients.

Eur J Nucl Med Mol Imaging 2020 03 15;47(3):632-641. Epub 2019 Nov 15.

Adana Dr. Turgut Noyan Research and Treatment Center, Department of Nuclear Medicine, Başkent University Faculty of Medicine, Adana, Turkey.

Purpose: To evaluate the effect of neoadjuvant androgen deprivation treatment (ADT) on prostate-specific membrane antigen (PSMA) tracer uptake demonstrated in Ga-PSMA-positron emission tomography (PET/CT) in non-metastatic hormone-naïve prostate cancer (PC) patients.

Materials And Methods: The clinical data of 108 PC patients who received neoadjuvant ADT were retrospectively analyzed. All patients had a baseline Ga-PSMA-PET/CT scan, and a second scan was delivered median of 2.9 months after the initiation of ADT. The maximum standardized uptake value (SUV) of primary tumor (SUV) and metastatic lymph nodes (SUV) as well as PSA response were assessed between pre- and post-ADT Ga-PSMA-PET/CT scans.

Results: There were significant decreases in posttreatment serum PSA, SUV, and SUV. A decrease in SUV was seen in 91 patients (84%) with a median value of 66% (range, 5-100%), while 17 patients (16%) had no change in or an increase in PSMA tracer uptake with a median value of 24% (range, 0-198%). Patients with Gleason score (GS) of 7 had significantly higher metabolic response rates compared to other patients. The disease progression was significantly higher only in patients with GS > 7 disease compared to GS 7 disease. The PSA response to ADT was the lowest in patients with ISUP high-grade tumors. A total of 16 patients (15%) had progressive disease, and in 9 patients (8%), radiotherapy decisions were modified according to posttreatment Ga-PSMA-PET/CT scans.

Conclusions: The current study includes the largest number of patients analyzed to date and demonstrates that ADT causes a significant decrease in serum PSA values and SUV and SUV. The authors demonstrate that Ga-PSMA-PET/CT may be used as a quantitative imaging modality after neoadjuvant ADT in hormone-naïve non-metastatic PC patients.
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http://dx.doi.org/10.1007/s00259-019-04581-4DOI Listing
March 2020

Integration of 68Ga-PSMA-PET/CT in Radiotherapy Planning for Prostate Cancer Patients.

Clin Nucl Med 2019 Sep;44(9):e510-e516

Departments of Radiation Oncology.

To assess the role of Gallium-labeled-prostate-specific membrane antigen PET/CT (Ga-PSMA-PET/CT) in risk group definition and radiotherapy planning in the initially planned definitive radiotherapy (RT) for prostate cancer patients.

Methods: The clinical data of 191 prostate cancer patients treated with definitive intensity-modulated RT were retrospectively analyzed. All patients were initially staged with thoracoabdominal CT and bone scintigraphy, and the second staging was performed using Ga-PSMA-PET/CT. Both stages were evaluated for the decision making of RT and any change in RT target volumes.

Results: After staging with Ga-PSMA-PET/CT, 26 patients (13.6%) had risk group changes, 16 patients (8.4%) had an increase in risk group, and 10 patients (5.2%) had a decrease in risk group. Down-staging occurred in 22 patients (11.5%), and upstaging was observed in 30 patients (15.7%). A total of 26 patients (13.6%) had nodal stage changes. After the Ga-PSMA-PET/CT scans, the number of metastatic patient increased to 17 (8.9%), with 4 of them moving from oligo- to polymetastatic disease. An additional irradiation of pelvic lymphatics and metastatic site was performed in 13 patients (6.8%) and 6 patients (3.2%), respectively. The RT was aborted in 4 patients (2.1%) because of parenchymal or distant site metastasis observed in the Ga-PSMA-PET/CT.

Conclusions: We found that Ga-PSMA-PET/CT causes considerable migration in stage, risk group, and RT field arrangements, especially in high-risk patients regardless of the GS and baseline prostate-specific antigen values alone. Ga-PSMA-PET/CT seems to have a great influence on RT decision making in prostate cancer patients.
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http://dx.doi.org/10.1097/RLU.0000000000002691DOI Listing
September 2019

Evaluation of cyclic direct radionuclide cystography findings with DMSA scintigraphy results in children with a prior diagnosis of vesicoureteral reflux.

Nucl Med Commun 2019 Jun;40(6):583-587

Department of Nuclear Medicine, Adana Teaching and Medical Research Center, Faculty of Medicine, Baskent University, Ankara, Turkey.

Objectives: Direct radionuclide cystography (DRC) with cyclic imaging is a sensitive method used for the detection of vesicoureteral reflux (VUR). Radionuclide cystography is generally recommended for follow-up evaluation of VUR. The aim of this study was to evaluate cyclic DRC with DMSA scan results during the follow-up period in children with a prior diagnosis of VUR.

Patients And Methods: DRC findings of 85 children with VUR were evaluated together with DMSA findings during follow-up. VUR grade was classified anatomically as grades I, II, and III reflux. Reflux grades of II and III were regarded as high-grade reflux. Reflux was also graded functionally as transient and continuous on the basis of the presence of reflux on either filling or voiding phases (transient) or both phases (continuous) of at least one cycle.

Results: Among 85 children, 32 (38%) exhibited reflux. In five patients, reflux was observed on both sides, and a total of 37 refluxing units (RUs) were evaluated. According to the highest grade attained in either cycle, 31 (84%) units had grade II, five had grade I and one had grade III reflux. Reflux was continuous in 23 (62%) and transient in 14 (38%) RUs. The incidence of an abnormal scan result was higher in continuous reflux group (78%) than in high-grade anatomic reflux group (59%). The addition of a second cycle resulted in the diagnosis of continuous reflux in six (26%) more RUs. DMSA scan findings correlated significantly with functional reflux classification (P<0.05), but not with anatomic reflux classification (P>0.05).

Conclusion: Functional classification of VUR into continuous and transient reflux resulted in higher correlation with DMSA scan findings compared with anatomic reflux grading in follow-up patients with VUR. Cyclic imaging contributed to continuous reflux diagnosis. The significance of functional information obtained from cyclic DRC in initial diagnostic workup, management, and follow-up of children with urinary tract infection needs to be determined with further studies.
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http://dx.doi.org/10.1097/MNM.0000000000000994DOI Listing
June 2019

Prognostic values of ADC and SUV of the primary tumour in cervical cancer patients treated with definitive chemoradiotherapy.

J Obstet Gynaecol 2019 Feb 24;39(2):224-230. Epub 2018 Oct 24.

b Department of Radiology , Baskent University Faculty of Medicine , Ankara , Turkey.

We analysed the correlation of F-fluorodeoxyglucose uptake into primary tumours using the maximum standardised uptake value (SUV) and the mean apparent diffusion coefficient (ADC) values in magnetic resonance imaging (MRI) with the clinical and pathological factors in patients with cervical cancer who were treated with concurrent chemoradiotherapy. The patients were stratified according to the primary tumour pre-treatment ADC and SUV cut-off values. There were significant correlations between the SUV of the primary tumour and tumour size, and the treatment response. The correlation between the ADC and FIGO stage, tumour size, and the lymph node metastasis was significant. The SUV was significantly and inversely correlated with the ADC for cervical cancer (r = -0.44, p <.001). In the multivariate analysis, the primary tumour ADC, treatment response and the lymph node metastasis emerged as significant independent predictors of both OS and DFS, and of the primary tumour SUV for DFS. Tumour size has a borderline significance for OS. High SUV and low ADC of the primary tumour are important predictive factors for identifying high-risk patients with cervical cancer who are treated with definitive chemoradiotherapy. These results point to a future role for the diffusion-weighted MRI and for F-fluorodeoxyglucose positron emission tomography, not only in the staging of cervical cancer but as an aid in the selection of an adjuvant treatment regimen after chemoradiotherapy for individual patients. Impact statement What is already known on this subject? A negative correlation between primary tumour SUV derived from positron emission tomography (PET/CT) and ADC derived from diffusion weighted magnetic resonance imaging (DW-MRI) in various cancer types and cervical cancer has been demonstrated. However, the prognostic value of primary tumour SUV and ADC in cervical cancer patients treated with definitive chemoradiotherapy is not well studied yet. What the results of this study add? The patients with high-risk features (larger tumours, extensive stage, lymph node metastasis) had higher primary tumour SUV and lower ADC values. Primary tumour ADC and lymph node metastasis emerged as significant independent predictors of both overall and disease-free survival. This study demonstrated that the functional biomarkers delivered from PET-CT and DW-MRI are important in predicting the treatment outcomes in the squamous cell carcinoma of cervix treated with definitive chemoradiotherapy, where clinical and radiological findings are very important, since these patients are not staged surgically. What are the implications of these findings for clinical practice and/or further research? Based on these findings, there may be a future role of DW-MRI and FDG/PET-CT not only in the staging of cervical cancer but as an aid in the selection of an adjuvant treatment regimen after chemoradiotherapy (ChRT) for individual patients.
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http://dx.doi.org/10.1080/01443615.2018.1492528DOI Listing
February 2019

Hounsfield unit value has null effect on thyroid nodules at 18F-FDG PET/CT scans.

Arch Endocrinol Metab 2018 Aug;62(4):460-465

Baskent University Faculty of Medicine Department of Endocrinology and Metabolism, Adana, Turkey.

Objectives: Detection rate of thyroid nodules is increasing with the use of new imaging modalities, especially in screening for malignancies. Positron emission tomography/computed tomography (PET/ CT)-positive thyroid nodules should be differentiated for malignancy to avoid unnecessary operations and further follow-up. Most trials evaluate the role of SUVmax, but there is no definitive information about the utility of Hounsfield unit (HU) values for prediction of malignancy. This study aimed to evaluate the HU values beside SUVmax for detecting malignancy risk of PET/CT-positive thyroid nodules.

Subjects And Methods: Results of 98 cancer patients who had fine needle aspiration biopsy (FNAB) for thyroid nodules detected on PET/CT between January 2011 and December 2015 were assessed. The FNABs and surgical pathological results were recorded.

Results: FNABs revealed benign results in 32 patients (32.7%), malignant in 18 (18.4%), non-diagnostic in 20 (20.4%), and indeterminate in 28 (28.5%). Twenty-four patients underwent thyroidectomy. The mean HU values were not significantly different in benign and malignant nodules (p = 0.73). However, the mean SUVmax was significantly higher (p < 0.001) in malignant ones. Area under curve (AUC) was 0.824 for SUVmax; the cut-off value was over 5.55 (p < 0.001), with 80% sensitivity, 84.5% specificity.

Conclusions: Our current study demonstrated that HU value does not add any additional valuable information for discriminating between malignant and benign thyroid nodules. We also defined a SUV cut-off value of 5.55 for malignant potential of thyroid nodules detected on PET/CT Arch Endocrinol Metab. 2018;62(4):460-5.
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http://dx.doi.org/10.20945/2359-3997000000063DOI Listing
August 2018

An old enemy not to be forgotten during PET CT scanning of cancer patients: tuberculosis.

Contemp Oncol (Pozn) 2016 8;20(2):188-91. Epub 2014 Jul 8.

Department of Medical Oncology, Medical Faculty, Baskent University, Ankara, Turkey.

Aim Of The Study: Positron emission tomography-computed tomography (PET CT) scan is commonly used in current medical oncology practice as an imaging method. In this study we present data from cancer patients who were followed at our clinic and suspected of having tuberculosis during PET CT scanning. After the biopsy, they were diagnosed with concomitant tuberculosis.

Material And Methods: In this study, 14 patients who applied to our clinic and followed up due to cancer, and had PET CT scanning for the preliminary staging or further evaluation, were included. The patients were diagnosed with metastatic or recurrent disease, and their biopsy results revealed tuberculosis.

Results: The mean age was 57.8 years with SD (standard deviation) 13.1 years and gender distribution of 78.6% (n = 11) females and 21.4% (n = 3) males. None of the patients had tuberculosis in their personal history (0%). Among the patients, 5 (35.7%) were diagnosed with tuberculosis during the preliminary staging, whereas 9 (64.3%) were diagnosed during the follow-up after the treatment. The median time to tuberculosis diagnosis was 11 months (min-max: 3-24 months) after the treatment. The most commonly involved lymph nodes during PET CT scanning were mediastinal in 8 (64.3%), axillary in 3 (21.4%) and para-aortic in 3 (21.4%) patients. The mean SUVmax (maximum standardised uptake value) of lymph node involved by PET CT scanning was defined as 8.5 (SD 2.6).

Conclusions: Despite all improvements in modern medicine, tuberculosis is still a serious public health problem. It should always be considered in differential diagnosis while evaluating PET CT scanning results of cancer patients, because it may cause false positive results.
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http://dx.doi.org/10.5114/wo.2014.43985DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4925724PMC
June 2016

Is PET/CT Necessary in the Management of Early Breast Cancer?

Clin Nucl Med 2016 May;41(5):362-5

From the Departments of *Nuclear Medicine, †General Surgery, and ‡Pathology, Baskent University Adana Teaching and Research Center, Adana, Turkey.

Purpose: Advanced imaging methods in early breast cancers are not recommended before surgery. In contrast to the accepted guidelines, some recent studies have shown some benefits with the use of PET/CT in early-stage breast cancer. In this study, we aimed to document the efficacy of PET/CT in detection of distant metastasis as well as other primary cancers.

Patients And Methods: In this retrospective study, we reviewed the records of all women patients diagnosed with early breast cancer between March 2012 and December 2014. Besides demographics, we recorded the clinical TNM stage, histology of the tumor, and hormone receptor status. As PET/CT imaging is a routine procedure in our center for early breast cancer, tumor size, lymph node status, distant metastasis, and possible other primary malignancies detected by PET/CT were also recorded.

Results: Of the 419 women included in the study, 24.8% were clinically staged as stage I while the rest were stage II. Distant metastases were detected in 42 patients (10%). The yield of PET/CT in detecting metastasis was significant in stage II patients compared with stage I patients (12.4% vs 2.9%). In subgroup analysis of stage II patients, the performance of PET/CT in detecting metastasis was still evident in stage IIA patients (9.5%). In logistic regression analysis of the significant and near-significant factors (as detected by univariate analysis) effecting PET/CT detected distant metastasis, only nodal status (P = 0.053) was found to be significant.

Conclusions: We suggest the use of PET/CT in investigating metastasis in axilla positive and clinically stage II early breast cancer patients.
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http://dx.doi.org/10.1097/RLU.0000000000001165DOI Listing
May 2016

Choroidal Metastasis of Papillary Thyroid Carcinoma Demonstrated on SPECT-CT.

Clin Nucl Med 2016 May;41(5):403-4

From the Departments of *Nuclear Medicine, and †Ophthalmology, Baskent University Faculty of Medicine, Adana Teaching and Medical Research Center, Adana, Turkey.

We report a 68-year-old woman with papillary thyroid carcinoma metastasizing to choroid. The choroid metastasis was diagnosed with SPECT-CT and then was treated with high-dose radioactive iodine therapy.
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http://dx.doi.org/10.1097/RLU.0000000000001122DOI Listing
May 2016

Fluorodeoxyglucose-positron emission tomography/computed tomography imaging of squamous cell carcinoma arising in a meningomyelocele.

Korean J Intern Med 2016 Mar 23;31(2):411-2. Epub 2015 Dec 23.

Department of Pathology, Baskent University Faculty of Medicine, Ankara, Turkey.

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http://dx.doi.org/10.3904/kjim.2015.081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4773725PMC
March 2016

A Case of a Man With Isolated Breast Metastasis From Lung Adenocarcinoma Incidentally Detected by FDG PET/CT.

Clin Nucl Med 2016 Mar;41(3):e146-8

From the *Department of Nuclear Medicine, Faculty of Medicine, Baskent University, Konya; Departments of †Nuclear Medicine, and ‡Pathology, Faculty of Medicine, Baskent University, Adana, Turkey.

Breast metastases from an extramammary primary tumor are very rare, particularly in men. In this study, we present a case of a 74-year-old man with isolated breast metastasis from lung adenocarcinoma as an incidental finding on PET/CT and diagnosed concomitantly with the primary tumor. Detection of isolated incidental metastatic lesions in the breast on PET/CT imaging has a significant clinical impact on patients with known malignant disease due to change of disease stage, management, and also treatment method.
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http://dx.doi.org/10.1097/RLU.0000000000001055DOI Listing
March 2016

Venous thrombosis of sarcoidosis as an unusual incidental finding on 18F-fluorodeoxyglucose positron emission tomography/computed tomography.

Indian J Nucl Med 2015 Oct-Dec;30(4):352-4

Department of Pathology, Faculty of Medicine, Baskent University, Turkey.

Sarcoidosis is defined as a multisystem granulomatous disorder of unknown cause. Venous thrombosis (VT) in the sarcoidosis is rare. The routine use of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has resulted in clinicians detecting many incidental findings, which have proven to be clinically significant such as thrombosis. Here, we present a case with VT of sarcoidosis in the inferior vena cava and portal vein as an unusual incidental finding on 18F-FDG PET/CT.
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http://dx.doi.org/10.4103/0972-3919.164027DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4579626PMC
October 2015

Multifocal soft tissue Langerhans' cell histiocytosis treated with PET-CT based conformal radiotherapy.

Jpn J Radiol 2015 Sep 26;33(9):603-6. Epub 2015 Jul 26.

Division of Medical Oncology, Baskent University Faculty of Medicine, Ankara, Turkey.

Introduction: Langerhans' cell histiocytosis (LCH) is a proliferative disorder of Langerhans cells, which is seen extremely rarely in adults. Conventional imaging modalities, such as skeletal surveys and bone scans, were accepted to be standard methods for diagnosis; however, 18-fluorodeoxyglucose positron emission tomography (PET-CT) has been increasingly used.

Methods: We report on a 33-year-old female patient with disseminated LCH treated with radiotherapy and systemic chemotherapy where PET-CT has been used for defining the extent of the disease, RT planning and assessment of treatment response during follow-up.

Results: The patient was treated with 24 Gy 3-dimensional conformal radiotherapy (RT), given as 2 Gy a day, 5 days a week. The patient was also treated with systemic prednisolone 20 mg/m(2), concurrently. The chemotherapeutic regimen switched to cytosine-arabinoside with a dose of 100 mg/m(2) subcutaneously daily for 4 days, vincristine 1.5 mg/m(2) given on the 1st day and prednisolone 20 mg/m(2) for 4 cycles. After local RT with adjuvant chemotherapy, the patient was alive for 54 months and remained disease-free at last visit.

Conclusion: RT is a treatment choice in multi-system LCH as well as solitary lesions. Low-dose RT is adequate to control large masses of LCH including soft tissue and lymph nodes.
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http://dx.doi.org/10.1007/s11604-015-0466-6DOI Listing
September 2015

Focal 99mTc-DMSA Uptake in Lung Parenchyma Without Structural Alterations on SPECT/CT.

Clin Nucl Med 2015 Nov;40(11):e520-1

From the Department of Nuclear Medicine, Baskent University Adana Teaching and Research Center, Adana, Turkey.

Static renal scintigraphy with Tc-DMSA is commonly used for the evaluation of renal morphology and function. Extrarenal uptake of Tc-DMSA is a rare finding described previously on sites such as bone metastasis, hemangioma, and splenic amyloidosis. We report a case with Tc-DMSA activity in the lungs.
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http://dx.doi.org/10.1097/RLU.0000000000000847DOI Listing
November 2015

The Role of PET-CT in Evaluation of Cervical Lymph Node Metastases in Oral Cavity Squamous Cell Carcinomas.

Turk Arch Otorhinolaryngol 2015 Jun 1;53(2):67-72. Epub 2015 Jun 1.

Department of Nuclear Medicine, Başkent University Faculty of Medicine, Adana, Turkey.

Objective: The aim of this study is to determine the sensitivity and specificity of positron emission tomography-computed tomography (PET-CT) in the evaluation of cervical lymph node metastasis in oral cavity squamous cell cancers (SCCs) and to determine the SUV-max values in differentiating reactive and metastatic lymph nodes as a supportive parameter.

Methods: In this study, 23 patients were included who were diagnosed with oral cavity SCC and treated with surgery between 2006 and 2013 in our department. All the patients were scanned with PET-CT during the pretreatment evaluation. Detailed pretreatment PET-CT (retention sites and SUV-max values) and histopathological examination results were obtained. SPSS 17.0 software package was used for statistical analysis of the data. Categorical measurement was summarized as number and percentage and continuous measurements as mean and standard deviation (median and minimum-maximum where necessary). Chi-square test or Fisher's test were used in the comparison of categorical variables. Compliance of methods was assessed by Kappa coefficient analysis. In this study, the advantages of PET-CT were determined by the calculation of sensitivity and specificity values with histopathological examination results considered as the gold standard, and SUV-max value was assessed by examining the area under the ROC curve. In all tests, the level of statistical significance was accepted as 0.05.

Results: The threshold value for SUV-max depending on the data of the histopathological examination and results of PET-CT of the 23 patients was 2.50. The reliability of this threshold was determined as AUC=0.819. In demonstrating neck metastasis in patients with cancer of the oral cavity, PET-CT has a sensitivity of 89% and specificity of 98%. Compliance between the histopathological examination and PET-CT for metastatic cervical lymph nodes was determined to be 0.416 by kappa coefficient analysis.

Conclusion: There was FDG uptake on PET-CT in the cervical lymph node regions of all patients with metastatic cervical lymph nodes. There were no metastases in any of the patients with no FDG retention. The sensitivity and specificity of PET-CT in determining cervical lymph node metastasis were 89% and 98%, respectively, with a threshold SUV-max value considered as 2.50 in patients with FDG retention.
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http://dx.doi.org/10.5152/tao.2015.608DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5783003PMC
June 2015

Positron emission tomography evaluation of sinonasal inverted papilloma and related conditions: a prospective clinical study.

Kulak Burun Bogaz Ihtis Derg 2015 ;25(1):9-15

Department of Otolaryngology, Medical Faculty of Başkent University, Adana Seyhan Hospital, 01110 Seyhan, Adana, Turkey.

Objectives: This study aims to determine whether there is a difference between inverted papilloma (IP) and nasal polyp, and squamous cell carcinoma (SCC) with regard to fluorodeoxyglucose uptake.

Patients And Methods: Between September 2007 and May 2014, positron emission tomography computed tomography (PET/CT) images of 27 patients (20 males, 7 females; mean age 53.4 years; range 18 to 74 years), with unilateral polyposis diagnosed on examination and tomographic scans of paranasal sinus were obtained. Nasal polyps in eight of the patients (group 1), IP in 10 patients (group 2), and SCC in nine patients (group 3) were found. The data were compared with Kruskal-Wallis and Mann-Whitney U tests.

Results: The mean maximum standardized uptake (SUVmax) values were found to be 2.9 in the group 1; 7.8 in the group 2, and 17.8 in the group 3. There was significant difference in the SUVmax values between the group 1 and the group 2 (p=0.016), the group 1 and the group 3 (p=0.001), and the group 2 and the group 3 (p=0.01).

Conclusion: According to the results of this study, PET/CT scan in the patients with unilateral polyposis is invaluable to distinguish nasal polyp from IP and SCC. It is also useful to recognize the distinctions between IP and SCC. In our study of 27 patients, a SUVmax of 6 or higher ruled out the presence of nasal polyp [95% CI (5.93 to 13.39), specificity 100%] might also be clinically useful.
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http://dx.doi.org/10.5606/kbbihtisas.2015.45212DOI Listing
June 2016

Elastofibroma dorsi incidentally detected by (18)F-FDG PET/CT imaging.

Ann Nucl Med 2015 Jun 11;29(5):420-5. Epub 2015 Feb 11.

Department of Nuclear Medicine, Faculty of Medicine, Baskent University, Ankara, Turkey,

Objective: Elastofibroma dorsi (ED) is a rare pseudotumor of the soft tissues that can also show 18F-fluorodeoxyglucose ((18)F-FDG) uptake on positron emission tomography combined with computed tomography (PET/CT) imaging. The aim of this retrospectively study was to describe the metabolic characteristics of ED incidentally detected by (18)F-FDG PET/CT imaging.

Materials And Methods: Between November 2009 and August 2013 at our institution, 10,350 consecutive PET/CT examinations were retrospectively investigated. In 176 of these patients, ED was recorded as an incidental finding. Fifty-five of 176 patients also had follow-up scans after chemoradiotherapy. A total of 231 scans with ED in 176 patients were identified. To determine the metabolic activity of ED, the maximum standardized uptake value (SUVmax) was calculated semiquantitatively. For measurement size of ED, the longest axis of transaxial CT images was used. Seven of the 176 patients underwent surgery due to suspected metastases and/or invasion of primary malignancy and/or symptoms or incidental during surgery.

Results: The prevalence of ED in our series was 1.7%. The lesions were located in the subscapular region in all patients, except in one case with a lesion in the infrascapular region. A total of 419 ED lesions in 231 scan of 176 patients were evaluated. Mean ± SD SUVmax and long axis values for these 419 lesions were 2.31 ± 0.61 (range 1.0-4.30) and 56.78 ± 17.01 mm (range 19-112 mm), respectively. Of these 176 patients, 141 (80.1%) had bilateral lesions and 35 (19.9%) had unilateral lesions. There were statistically significant differences in the SUVmax and long axis values between the right and left side in the bilateral lesions (p = 0.001). No significant differences in the SUVmax and long axis values of the lesion were found between pre- and posttreatment in the patients with follow-up scans.

Conclusion: Elastofibroma dorsi located in the scapular region is usually bilateral, asymmetric and with mild or moderate metabolic activity on PET/CT imaging. In addition, the metabolic activity and size of ED remained stable after chemoradiotherapy. Awareness of these metabolic characteristics of ED is important for preventing misinterpretation during (18)F-FDG PET/CT studies.
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http://dx.doi.org/10.1007/s12149-015-0959-5DOI Listing
June 2015

Prognostic value of 18F-fluorodeoxyglucose uptake in pelvic lymph nodes in patients with cervical cancer treated with definitive chemoradiotherapy.

Gynecol Oncol 2015 Apr 29;137(1):40-6. Epub 2015 Jan 29.

Department of Nuclear Medicine, Baskent University Faculty of Medicine, Ankara, Turkey.

Purpose: To evaluate the prognostic significance of the maximum standardized uptake (SUVmax) value for pelvic lymph nodes in patients with cervical cancer and its impact on treatment response, disease control, and survival.

Methods: Ninety-three patients with pelvic or para-aortic metastasis detected by PET/CT and treated with definitive chemoradiotherapy were evaluated. The impact of pelvic lymph node SUVmax on prognostic factors and treatment outcomes was assessed.

Results: The size and SUVmax of pelvic lymph nodes were significantly correlated (r=0.859; p<0.001). Patients with pelvic and para-aortic lymph node metastases had significantly higher SUVmax values for both primary tumor (23.4±9.2 vs. 18.5±7.3; p=0.01) and pelvic lymph nodes (11.4±4.6 vs. 7.4±3.8; p=0.001). Patients with pelvic lymph node SUVmax≥7.5 had significantly higher primary tumor SUVmax, larger pelvic lymph nodes, higher rates of para-aortic lymph node metastasis, and lower post-therapy complete response rates. Overall survival (OS) and disease-free survival (DFS) rates were significantly higher in patients with SUVmax<7.5 compared to patients with SUVmax≥7.5. In a multivariate analysis, pelvic lymph node SUVmax and post-therapy metabolic response were significant prognostic factors for both OS and DFS for all patients, but no significant prognostic factors were found in pelvic lymph node metastasis only.

Conclusions: Patients with highly FDG-avid pelvic lymph nodes have a higher risk of disease recurrence with worse survival. Identification of these patients may assist in the evaluation of the clinical benefits of additional treatments.
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http://dx.doi.org/10.1016/j.ygyno.2015.01.542DOI Listing
April 2015

Simultaneous occurrence of medullary and differentiated thyroid carcinomas. Report of 4 cases and brief review of the literature.

Hell J Nucl Med 2014 May-Aug;17(2):148-52. Epub 2014 Jul 5.

Baskent University Faculty of Medicine, Saray Street No. 1, 42080, Selcuklu, Konya, Turkey.

Simultaneous occurrence of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) in a single patient is an unusual event. The incidence, cell origin, histopathology features and prognosis of these two carcinomas are considered completely different. The aim of this retrospective study was to describe clinical, pathologic characteristics and the prevalence of diagnosing such patients in our clinic. Between October 2003 and December 2013, 1.420 consecutive patients diagnosed by histology as having differentiated thyroid carcinoma (DTC) and treated with radioactive iodide (RAI) were retrospectively investigated. Of these, 4 patients were diagnosed by histology as having simultaneous MTC and PTC. The clinical and pathology characteristics of these patients are described. The prevalence of simultaneous MTC and PTC of these 4 patients in our clinic was 0.28% of all patients with DTC. The age of the 4 patients ranged from 44 to 63 years and were three females and one male. These patients are currently alive without disease from either of the two types of cancer. In two of these patients, MTC was located in the left and PTC in the right thyroid lobe. One patient had MTC in the right lobe and PTC in both lobes. The remaining patient had both cancers in the left lobe as a mixed tumor. We are able to present the pathology of only 2 of these 4 patients. In these 2 patients MTC was located in the left and PTC in the right thyroid lobe, one of them was female and the other was male, aged 44 and 49, respectively. In conclusion, our results suggested that simultaneous occurrence of MTC and PTC had a prevalence in our clinic of 0.28% among 1420 consecutive patients with DTC or 0.14%, if only the 2 patients in whom we are able to present their pathology slides are considered. Our cases suggest that these two tumors are usually independent and coincidental events in every patient.
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http://dx.doi.org/10.1967/s002449910137DOI Listing
September 2014

Pyelo-cystic Reflux in F-18 FDG PET Scan Due to Ureteral Obstruction.

Authors:
Mehmet Reyhan

Nucl Med Mol Imaging 2013 Sep 11;47(3):222-3. Epub 2013 Jun 11.

Department of Nuclear Medicine, Baskent University School of Medicine, Adana, Turkey.

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http://dx.doi.org/10.1007/s13139-013-0210-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4035199PMC
September 2013

Kikuchi-Fujimoto disease as a rare cause of benign lymphadenopathy and (18)F-FDG PET/CT findings.

Hell J Nucl Med 2014 Jan-Apr;17(1):41-4. Epub 2014 Feb 25.

Department of Nuclear Medicine, Baskent University, Faculty of Medicine, Saray Street No. 1, 42080: Selcuklu, Konya, Turkey.

Kikuchi-Fujimoto disease (KFD) is an uncommon benign and self-limited disease, characterized by cervical lymphadenopathy. This disease is generally diagnosed on the basis of an excisional biopsy of affected lymph nodes. However, clinical presentation and histopathological findings of KFD could lead to a wrong initial diagnosis, of tuberculosis, systemic lupus erythymatosus or malignant lymphoma. Laboratory tests are not specific. Imaging modalitites give confusing results. Affected lymph nodes of patients with KFD can exibit (18)F-FDG uptake on PET/CT imaging similar to malignant lymphoma. Therefore, the differential diagnosis of KFD should be considered in patients with cervical and/or generalized lymphadenopathy. Accurate diagnosis of KFD by histology is essential in avoiding unnecessary emotional and mental distress associated with the diagnosis of lymphoma.
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http://dx.doi.org/10.1967/s002449910115DOI Listing
February 2014

Treatment outcomes of patients with cervical cancer with complete metabolic responses after definitive chemoradiotherapy.

Eur J Nucl Med Mol Imaging 2014 Jul 22;41(7):1336-42. Epub 2014 Feb 22.

Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana, Turkey,

Purpose: We sought to evaluate failure patterns and prognostic factors predictive of recurrences and survival in cervical cancer patients who are treated with definitive chemoradiotherapy (ChRT), who have a subsequent complete metabolic response (CMR) with (18) F-fluorodeoxyglucose positron-emission tomography (FDG-PET) after treatment.

Methods: The records of 152 cervical cancer patients who were treated with definitive chemoradiotherapy were evaluated. All patients underwent pre-treatment positron emission tomography (PET-CT), and post-treatment PET-CT was performed within a median of 3.9 months (range, 3.0-9.8 months) after the completion of ChRT. The prognoses of partial response/progressive disease (PR/PD) cases (30 patients, 18 %) and CMR cases (122 patients, %82) were evaluated. Univariate and multivariate analysis effecting the treatment outcome was performed in CMR cases.

Results: The median follow-ups for all patients and surviving patients were 28.7 (range, 3.3-78.7 months) and 33.2 months (range, 6.23-78.7 months), respectively. Four-year overall survival (OS) rate was significantly better in patients with CMR compared to patients with PR/PD (66.9 % vs. 12.4 %, p < 0.001, respectively). Patients with PR/PD had higher maximum standardized uptake value (SUVmax) of primary cervical tumor (26.4 ± 10.1 vs. 15.9 ± 6.3; p < 0.001) and larger tumor (6.4 cm ± 2.3 cm vs. 5.0 cm ± 1.4 cm; p < 0.001) compared to patients with CMR. Of the 122 patients with post-treatment CMRs, 25 (21 %) developed local, locoregional, or distant failure. In univariate analysis, tumor size ≥ 5 cm, 'International Federation of Obstetricians and Gynecologists' (FIGO) stage ≥ IIB, and pelvic and/or para-aortic lymph node metastasis were predictive of both overall survival (OS) and disease-free survival (DFS), while histology was predictive of only OS. In multivariate analysis, tumor size, stage and lymph node metastasis were predictive of OS and DFS.

Conclusion: Although CMR is associated with better outcomes, relapses remain problematic, especially in patients with bulky tumors (≥ 5 cm), extensive stage (≥ IIB) or pelvic and/or para-aortic lymph node metastasis. These findings could support the need for more aggressive treatment or adjuvant chemotherapy regimens.
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http://dx.doi.org/10.1007/s00259-014-2719-5DOI Listing
July 2014

Prognostic value of pretreatment 18F-fluorodeoxyglucose uptake in patients with cervical cancer treated with definitive chemoradiotherapy.

Int J Gynecol Cancer 2013 Jul;23(6):1104-10

Department of Radiation Oncology, Baskent University Faculty of Medicine, Adana, Turkey.

Objective: We analyzed the correlation of F-fluorodeoxyglucose (FDG) uptake into primary tumors using the maximum standardized uptake value (SUVmax) and clinicopathological factors of disease. The impact of the pretreatment SUVmax of the primary tumor on survival was investigated.

Materials And Methods: The records of 149 patients with biopsy-proven cervical cancer treated with definitive chemoradiotherapy (ChRT) were reviewed. All patients underwent pretreatment FDG positron emission tomography with computed tomography, and posttherapy FDG positron emission tomography with computed tomography was performed within a median interval of 4.2 months (range, 3.0-11.2 months) after the completion of chemoradiotherapy.

Results: The mean SUVmax in patients with lymph node metastasis was significantly higher than that in patients without metastasis (19.7 ± 8.2 vs 16.4 ± 8.2, respectively; P = 0.01). A significant difference existed between tumor size (<4 vs ≥4 cm) and the primary tumor SUVmax (14.7 ± 6.6 vs 18.7 ± 8.5, respectively; P = 0.02). The primary tumor pretreatment SUVmax for patients with complete remission was significantly lower than that of patients with partial response or progressive disease (15.6 ± 5.7 vs 28.0 ± 9.9, respectively; P < 0.001). The relationship between primary tumor FDG uptake and survival was evaluated by the cutoff value determined by receiver operating characteristic curve analysis. The area under the curve was 0.901 (P < 0.001; 95% confidence interval, 0.848-0.954), and 15.6 was determined as the SUVmax cutoff value. The 4-year actuarial overall survival (OS) and disease-free survival for SUVmax of less than 15.6 compared with SUVmax of 15.6 or greater were 85% vs 34% (P < 0.001) and 80% vs 29%, respectively (P < 0.001). In multivariate analysis, age, SUVmax of 15.6 or greater, and lymph node metastasis were independent prognostic factors of OS, and International Federation of Gynecology and Obstetrics stage IIB or higher, SUVmax of 15.6 or greater, and lymph node metastasis were significant factors for disease-free survival.

Conclusion: The primary tumor pretreatment SUVmax is correlated with increased tumor size and lymph node involvement at diagnosis, how well the primary tumor responds to treatment, the likelihood of disease recurrence, and OS.
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http://dx.doi.org/10.1097/IGC.0b013e3182989483DOI Listing
July 2013

A thoracic surgeon's perspective on the elastofibroma dorsi: A benign tumor of the deep infrascapular region.

Thorac Cancer 2013 02;4(1):35-40

Department of Thoracic Surgery, Faculty of Medicine, Baskent University, Adana, Turkey Department of Pathology, Faculty of Medicine, Baskent University, Adana, Turkey Department of Nuclear Medicine, Faculty of Medicine, Baskent University, Adana, Turkey.

Background: An elastofibroma is a benign, soft-tissue tumor and is important in the differential diagnosis of thoracic wall masses. Here, patients with elastofibromas who underwent thoracic surgery were retrospectively reviewed to elucidate elastofibroma formation and to facilitate the differential diagnosis.

Methods: This is a retrospective and descriptive study of a series of 30 patients with elastofibroma dorsi. The data was obtained by review of the hospital records.

Results: There were 27 female and three male patients (mean age, 55.13 ± 8.7 years) with a total of 42 elastofibroma dorsi tumors (12 bilateral cases, 18 unilateral cases) diagnosed between January 2004 and October 2011. Twenty patients (67%) underwent surgery as a result of subscapular swelling and pain. In 10 (33%) asymptomatic patients, elastofibromas were found incidentally during a thoracotomy. Imaging methods in symptomatic patients included computerized tomography (15 cases), magnetic resonance (three), and ultrasonography (two). For five patients, fluorodeoxyglucose uptake values were available and revealed mild metabolic activity in the elastofibromas. Elastofibromas were significantly larger in symptomatic patients (8.15 ± 1.9 vs. 6.2 ± 2.3; P= 0.02). Exposure to long-term repetitive micro-trauma was a precipitating factor in 23 (77%) patients. Seroma formation, the most common surgical complication, was observed in 40% of patients.

Conclusion: The differential diagnosis of elastofibroma dorsi is straightforward, and preoperative histology is unnecessary when the clinical, radiological, and metabolic characteristics are known. Repetitive micro-trauma may predispose to hyperproliferation of fibroelastic tissue, and genetics may also play a role. Surgical treatment can be reserved for cases with severe symptoms.
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http://dx.doi.org/10.1111/j.1759-7714.2012.00139.xDOI Listing
February 2013

Isolated mediastinal lymph node false positivity of [18F]-fluorodeoxyglucose-positron emission tomography/computed tomography in patients with cervical cancer.

Int J Gynecol Cancer 2013 Feb;23(2):337-42

Department of Radiation Oncology, Faculty of Medicine, Baskent University, Ankara, Turkey.

Objective: This study aimed to evaluate the degree of mediastinal involvement in patients with cervical cancer with isolated mediastinal [F]-fluorodeoxyglucose-positron emission tomography (FDG-PET) positivity as verified by histopathologic examination.

Methods: Two hundred twenty-eight patients with newly diagnosed cervical cancer and who underwent FDG-PET imaging were analyzed. Twenty-nine patients (17%) had disseminated disease detected with PET/computed tomography (CT). Only 10 patients (4%) had increased FDG uptake in mediastinal lymph nodes alone. Of the 10 patients with mediastinal disease, 2 refused surgical mediastinal lymph node biopsy and did not receive any treatment. Patients with suspected paratracheal or subcarinal lymph node metastasis detected on PET/CT underwent mediastinoscopy, and those with hilar metastasis had video-assisted mediastinal lymphadenectomy. Treatment was delivered according to final staging based on histopathologic confirmation of mediastinal lymph node involvement.

Results: The mean (SD) maximum standardized uptake values for primary cervical tumor and mediastinal lymph nodes were 19.7 (10.3) and 7.5 (1.6), respectively. Of 8 patients who underwent mediastinal lymph node confirmation, 6 (75%) were tumor free, demonstrating granulomatous changes, and were treated curatively. No patients had residual or recurrent disease at the primary site, and all but 1 were alive without disease. Two patients with confirmed mediastinal lymph node metastasis were treated palliatively and died between 9 and 11 months after diagnosis.

Conclusions: Positron emission tomography/CT is an important tool for lymphatic staging and evaluation of distant metastases in cervical cancer. However, PET/CT should be interpreted cautiously for isolated mediastinal involvement; surgical evaluation is required for accurate staging and appropriate treatment decisions to achieve better outcomes.
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http://dx.doi.org/10.1097/IGC.0b013e31827e00ccDOI Listing
February 2013

Comparison of standardized uptake values obtained from two- and three-dimensional modes of fluorine-18 fluorodeoxyglucose PET-CT in oncological cases.

Diagn Interv Radiol 2013 Mar-Apr;19(2):126-9

Clinic of of Nuclear Medicine, Hatay Antakya State Hospital, Hatay, Turkey.

Purpose: We investigated the usability of standardized uptake values (SUV) obtained from both two- and three-dimensional (2D and 3D) positron-emission tomography and computed tomography (PET-CT) imaging, and compared the images obtained from these techniques in terms of image quality, lesion detectability, and the presence of artifacts.

Materials And Methods: Image data from 100 patients, who had undergone two PET imagings obtained in 2D and 3D mode after a low dose CT, were evaluated prospectively. Subjective analysis of 2D and 3D images was performed by two readers evaluating the following criteria: overall image quality, detectability of each identified lesion, and the presence of artifacts. The lesions recognized by the readers were also analyzed quantitatively by measuring SUV values.

Results: There was a significant difference between the SUVs obtained in 2D and 3D modes. Regardless if the first scan was performed in 2D or 3D mode, the values obtained from 3D imaging were significantly lower than those obtained from 2D imaging (mean SUV(max) was 10.48±7.57 for 2D, and 9.66±6.93 for 3D, P < 0.001). Visual analysis did not reveal significant differences regarding lesion detectability between two modes.

Conclusion: In oncological PET-CT applications, SUV values are significantly lower in 3D compared with 2D mode. Thus when serial scanning is needed to evaluate response to therapy in the same patient, the imaging modality should be taken into account and performed with the same method to avoid misinterpretation. Additionally, 3D PET-CT imaging can be used instead of 2D PET-CT due to its shorter scanning time without loss of lesion detectability.
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http://dx.doi.org/10.4261/1305-3825.DIR.6113-12.1DOI Listing
January 2014

CT- versus coregistered FDG-PET/CT-based radiation therapy plans for conformal radiotherapy in colorectal liver metastases: a dosimetric comparison.

Jpn J Radiol 2012 Oct 30;30(8):628-34. Epub 2012 Jun 30.

Department of Radiation Oncology, Adana Medical Faculty, Baskent University, Kisla Saglik Yerleskesi, 01120 Adana, Turkey.

Purpose: Our aim was to compare computed tomography (CT) and coregistered [(18)F]-fluorodeoxyglucose positron emission tomography CT-(FDG-PET/CT) based delineation of gross tumor volume (GTV) in unresectable colorectal liver metastasis (CRLM).

Materials And Methods: Fifty-four patients with unresectable CRLM were enrolled but 16 were excluded due to detection of additional hepatic metastases in ten on PET/CT scans, precluding radiotherapy because of transcendent critical organ doses beyond tolerable limits; and of extrahepatic metastases in six. For 38 eligible patients, both CT and PET/CT images were acquired, and two 3D conformal plans were made using the CT and FDG-PET/CT fusion data sets. Radiotherapy plans (RTP) and doses to critical organs were analyzed.

Results: Comparisons between two RTPs revealed need for change in GTV in 31 of 38 analyzable patients (81.6 %). In 25 (65.8 %) patients, GTV was significantly increased, with a median of 33.2 % (p < 0.001), whereas median 12.8 % decrease in six (15.8 %) (p < 0.001). There were no clinically meaningful differences in critical organ doses.

Conclusion: Coregistered FDG-PET/CT may improve delineation of GTV and theoretically reduce the likelihood of geographic misses in unresectable CRLM. Additionally, integration of FDG-PET/CT in the initial assessments of CRLM may spare almost one third of patients from potentially futile radical interventions.
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http://dx.doi.org/10.1007/s11604-012-0101-8DOI Listing
October 2012

18F-FDG uptake in diffuse peritoneal lymphomatosis.

Clin Nucl Med 2012 Jul;37(7):e176-7

Department of Nuclear Medicine, Baskent University School of Medicine, Adana, Turkey.

A 38-year-old man presented with declining appetite and progressive abdominal distention. Abdominal ultrasonography revealed omental and bowel wall thickening. Histopathologic examination showed a high-grade lymphoblastic Burkitt-like B-cell lymphoma. 18F fluorodeoxyglucose positron emission tomography/computed tomography images showed diffusely increased metabolic activity in the thickened omentum, intestines, mesentery, and peritoneum (omental caking). Diffuse peritoneal and omental seeding are well-known forms of dissemination of metastatic carcinoma. However, omental and peritoneal lymphomatosis are rare manifestations of high-grade lymphomas. This uncommon case demonstrates usefulness of F-18 fluorodeoxyglucose positron emission tomography/computed tomography in omental and peritoneal involvement in lymphoma.
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http://dx.doi.org/10.1097/RLU.0b013e31823ea93eDOI Listing
July 2012