Defining the optimal segmentation method for measuring somatostatin receptor expressing tumor volume on 68 Ga-DOTATATE positron emission tomography/computed tomography to predict prognosis in patients with gastroenteropancreatic neuroendocrine tumors.

OBJECTIVE: We aimed to compare different segmentation methods used to calculate prognostically valuable volumetric parameters, somatostatin receptor expressing tumor volume (SRETV), and total lesion somatostatin receptor expression (TLSRE), measured by 68 Ga-DOTATATE PET/CT and to find the optimal segmentation method to predict prognosis. PATIENTS AND METHODS: Images of 34 patients diagnosed with gastroenteropancreatic neuroendocrine tumor (GEPNET) who underwent 68 Ga-DOTATATE PET/CT imaging were reanalyzed. Four different threshold-based methods (fixed relative threshold method, normal liver background threshold method, fixed absolute standardized uptake value (SUV) threshold method, and adaptive threshold method) were used to calculate SRETV and TLSRE values. SRETV of all lesions of a patient was summarized as whole body SRETV (WB-SRETV) and TLSRE of all lesions of a patient was computed as whole body TLSRE (WB-TLSRE). RESULTS: WB-SRETVs calculated with all segmentation methods were statistically significantly associated with progression-free survival except WB-SRETV at which was calculated using adaptive threshold method. The fixed relative threshold methods calculated by using 45% (WB-SRETV 45% ) and 60% (WB-SRETV 60% ) of the SUV value as threshold respectively, were found to have statistically significant highest prognostic value (C-index = 0.704, CI = 0.622-0.786, P  = 0.007). Among WB-TLSRE parameters, WB-TLSRE 35% , WB-TLSRE 40% , and WB-TLSRE 50% had the highest prognostic value (C-index = 0.689, CI = 0.604-0.774, P  = 0.008). CONCLUSION: The fixed relative threshold method was found to be the most effective and easily applicable method to measure SRETV on pretreatment 68 Ga-DOTATATE PET/CT to predict prognosis in GEPNET patients. WB-SRETV 45% (cutoff value of 11.8 cm 3 ) and WB-SRETV 60% (cutoff value of 6.3 cm 3 ) were found to be the strongest predictors of prognosis in GEPNET patients.

18F-FDG PET/CT and 99mTc-MDP Bone Scintigraphy Findings of Multifocal Desmoid Fibromatosis.

ABSTRACT: Desmoid fibromatosis, also called desmoid tumors, is a group of locally aggressive fibromatous proliferative disorders. They represent less than 3% of all soft tissue sarcoma and are multifocal in approximately 10% of cases. However, there are only a few cases in the literature describing 18F-FDG PET/CT and 99mTc-MDP bone scan features of extra-abdominal desmoid fibromas, and all were solitary bone lesions. Herein, we presented a unique case of multifocal desmoid fibromatosis of bone illustrating the prospective value of 18F-FDG PET/CT and 99mTc-MDP bone scan in the evaluation of desmoid tumors.

"Wandering Spleen" With Lymphomatous Involvement.

ABSTRACT: Wandering spleen is a rare condition caused by either lack or the laxity of ligaments, which results malposition in the lower abdomen or pelvis. FDG PET/CT is the cornerstone of the staging procedures in the management of lymphomas leading to upstaging and picking up occult lesions in the spleen and extranodal sites. Herein, we reported initial staging 18 F-FDG PET/CT findings of a woman with Hodgkin lymphoma whose spleen was absent in normal position and multiple intense heterogenous hypermetabolism in a pelvic mass raised a suspicion of wandering splenic involvement. The confirmation was made with selective spleen SPECT/CT images thereafter.

Bone Lipogranuloma Mimicking Metastatic Disease on 18F-FDG PET/CT.

ABSTRACT: Primary bone lipogranuloma is an extremely rare disease associated with reactive inflammatory granulomatous reaction associated with exogenous or endogenous lipids. Herein, we report a case of bone lipogranuloma with intense 18F-FDG uptake, which mimics metastatic disease on 18F-FDG PET/CT in a patient with breast cancer.

The value of parathyroid scintigraphy on lesion detection in patients with normocalcemic primary hyperparathyroidism.

OBJECTIVE: Primary hyperparathyroidism (PHPT) is one of the most frequent endocrine diseases. Most of the patients with PHPT are asymptomatic, and only 20% of them become symptomatic with increasing levels of calcium. It has been reported that normocalcemic primary hyperparathyroidism (NPHPT) may be the incipient period of PHPT where calcium (Ca) levels are in normal range, and it may advance to overt PHPT. Early diagnosis of PHPT is important in order to prevent its complications. In this retrospective study, we aimed to evaluate the role of 99mTc-MIBI parathyroid scintigraphy on lesion detection in patients with NPHPT. MATERIAL AND METHODS: The parathyroid scintigraphy database was reviewed retrospectively in patients with PHPT. 117 patients who underwent 99mTc-MIBI scintigraphy were recruited to the study. Serum calcium level above 10.5mg/dl was considered as hypercalcemia. RESULTS: A total of 117 patients (female/male:98/19) mean serum PTH levels (mean±SD) were 149±97pg/ml in normocalcemic group (Ca:9.6±0.6mg/dl, n:38) and 189±135pg/ml in hypercalcemic group (Ca:11.4±0.6mg/dl, n:79) (p:0.072). The sex and ages were not different between the scintigraphy positive and negative groups, but the lesion detection rates with parathyroid scintigraphy were 42% in normocalcemic group and 81% in hypercalcemic group (p<0.0001). CONCLUSIONS: Several factors including serum Ca, the imaging protocol, existence of multiglandular disease, the size and MIBI biokinetics of the adenoma may influence lesion detectability in parathyroid scintigraphy. Although high serum Ca level is an important parameter in predicting its success, parathyroid scintigraphy remains a valuable diagnostic method even in patients with NPHPT.

Changes in 18F-FDG-PET/CT tumor metabolism are not consistent with pathologic complete response in hormone-positive breast cancer.

PURPOSE: Current evaluation of response to neoadjuvant chemotherapy (NAC) shows that it could achieve pathological complete response (pCR). The purpose of this study was to assess the consistency of maximum uptake values (SUVmax) changes and pCR in hormone-positive locally advanced breast cancer (LABC). METHODS: Ninety hormone-positive LABC patients treated at Marmara University Medical Oncology Clinic, Istanbul, Turkey, between 2009 and 2015 were retrospectively studied. All eligible patients (n=5) received NAC (4-8 cycles) and were evaluated for pCR. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18FFDG- PET/CT) scan was performed before and after the completion of NAC. The relative changes of SUVmax both in the primary tumor and the axilla were assessed for consistency with pCR. RESULTS: The patient median age was 46 years (range 26- 76). The patients 13.7% achieved pCR. Values of >50% (n=40) and <50% (n=11) SUVmax changes were not associated with pCR (15% and 18% respectively) (p=1.00). Patients with >75% SUVmax changes could achieve pCR of 20%. Interestingly, most patients with complete metabolic response did not achieve pCR (81%). The difference of the Ki67 levels before and after NAC, tumor localization, HER- 2 positivity, menopausal status, grade of differentiation, lymphovascular and perineural invasion were not associated with pCR. CONCLUSION: SUVmax changes in later cycles of NAC as commonly practised in oncology clinics were not consistent with pCR (p=1.0). Complete metabolic response may not be associated with pCR in hormone-positive LABC. However, almost 80% of patients had >50% decrease in SUVmax and may still have a chance for conservative surgery and less postoperative morbidity. Therefore, 18F-FDG-PET/CT may still have a role to evaluate the tumor response with a need of larger studies and analysis for cost-effectiveness.

Comparison of WHO, RECIST 1.1, EORTC, and PERCIST criteria in the evaluation of treatment response in malignant solid tumors.

AIM: To compare response assessment according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria in patients diagnosed with malignant solid tumors and who had received cytotoxic chemotherapy to establish the strength of agreement between each criterion. MATERIALS AND METHODS: Sixty patients with malignant solid tumors were included in this retrospective study. The baseline and the sequential follow-up fluorine-18-fluorodeoxyglucose PET/computed tomography (CT) of each patient were evaluated according to the WHO, RECIST 1.1, EORTC, and PERCIST criteria. PET/CT images were used for both metabolic and anatomic evaluation. The concurrent diagnostic CT and MRI images (performed within 1 week of PET/CT) were also utilized when needed. The results were compared using the κ-statistics. RESULTS: The response and progression rates according to the WHO criteria were 37 and 38%, respectively. The same ratios were also found for RECIST 1.1 (κ=1). The response and progression rates according to the EORTC criteria were 47 and 40%, respectively. When PERCIST criteria were used, one patient with progressive disease was upgraded to stable disease (κ=0.976). As we found the same results with WHO and RECIST 1.1 criteria, we used WHO criteria to compare the anatomic and metabolic criteria. When we compared the WHO and EORTC criteria, there was an agreement in 80% of the patients (κ=0.711). With WHO and PERCIST criteria, there was an agreement in 81.6% of the patients (κ=0.736). CONCLUSION: Significant agreement was detected when the WHO, RECIST 1.1, EORTC, and PERCIST criteria were compared both within as well as between each other.

Carbon-14 urea breath test: does it work in patients with partial gastric resection?

OBJECTIVE: The diagnostic value of Carbon-14 urea breath test (C-14 UBT) in the detection of Helicobacter pylori (H. pylori) infection in non-operated patients has been proved. However, the efficacy of C-14 UBT in patients with partial gastric resection (PGR) has not been evaluated yet. Herein, the results of the C-14 UBT and H. pylori stool antigen test (HpSAT) in this patient group were compared with the endoscopic findings. METHODS: Multi-breath samples C-14 UBT and HpSAT were performed in all patients on the same day. Histology was used as a gold standard for testing C-14 UBT and HpSAT diagnostic efficacies. RESULTS: 30 patients (mean age: 54.6 ± 11 year) with PGR were included. The sensitivity and specificity of standard C-14 UBT were 29 and 100 %, respectively. When breath samples were collected at 20th min, and >35 CPM was selected as radioactivity threshold, the sensitivity raised to 86 % without any loss of specificity. The specificity and sensitivity of the HpSAT were 71 and 96 %, respectively. CONCLUSIONS: The sensitivity of the standard C-14 UBT was very poor for patients with PGR, and results of HpSAT were superior in this population. Certain modifications are needed if C-14 UBT is to be used in PGR patients.

Clinical Impact of Preoperative Sentinel Lymph Node Imaging With SPECT/CT in the Management of Interscapular Malignant Melanoma.

A 31-year-old male patient with a biopsy-proven cutaneous malignant melanoma located in the interscapular area was referred to lymphoscintigraphy for preoperative sentinel lymph node mapping. Anterior and posterior planar images showed 3 hot spots suggesting left axillary sentinel nodes. Herein, we reported the contribution of preoperative SPECT/CT-guided sentinel lymph node excision on accurate staging, management, prognostic evaluation, and determination of the proper surgical positioning preoperatively.

Patients with Takayasu's arteritis having persistent acute-phase response usually have an increased major vessel uptake by 18F-FDG-PET/CT.

OBJECTIVES: Although not uniformly accepted, an increased uptake by 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) in large vessels is accepted to be a sign of active disease in Takayasu's arteritis (TAK). We aimed to investigate the value of 18F-FDG-PET/CT for clinical assessment in a subset of TAK patients having a persistent acute-phase response (APR) without any signs or symptoms of clinical disease activity. METHOD: We studied 14 patients (mean age: 38.6 ± 13.9 years, Female/Male: 11/3, and disease duration: 5.7 ± 5 years). Patients were clinically inactive (according to the definition of activity by Kerr et al.), while categorized as having "persistent" disease activity by physician's global assessment due only to APR. 18F-FDG uptake was graded using a four-point scale from grade 0 (no uptake present) to grade 3 (high grade: uptake higher than that of liver). Any uptake in major vessels with a grade ≥ 2 was accepted to be "active." RESULTS: Mean erythrocyte sedimentation rate was 50.8 ± 13.2 mm/hour and mean C-reactive protein level was 28.5 ± 22.1 mg/L. Active vasculitic lesions were observed by 18F-FDG-PET/CT in 9 of 14 (64.3%) patients. The median number of active vascular lesions was 2 (range: 1-5). A step-up treatment change was decided in 8 patients according to 18F-FDG-PET/CT results. CONCLUSION: We observed increased 18F-FDG uptake in the majority of TAK patients with an increased APR, but clinically silent disease. 18F-FDG-PET/CT showed the presence and localization of active inflammation in the aorta and its branches. Although specificity for observed lesions is not clear, 18F-FDG-PET/CT imaging may influence physician's assessment of clinical activity and treatment choices in TAK.

Long-Term Results of Fixed High-Dose I-131 Treatment for Toxic Nodular Goiter: Higher Euthyroidism Rates in Geriatric Patients.

OBJECTIVE: Geriatric patient population has special importance due to particular challenges. In addition to the increase in incidence of toxic nodular goiter (TNG) with age, it has a high incidence in the regions of low-medium iodine intake such as in our country. The aim of this study was to evaluate the overall outcome of high fixed dose radioiodine (RAI) therapy, and investigate the particular differences in the geriatric patient population. METHODS: One hundred and three TNG patients treated with high dose I-131 (370-740 MBq) were retrospectively reviewed. The baseline characteristics; age, gender, scintigraphic patterns and thyroid function tests before and after treatment, as well as follow-up, duration of antithyroid drug (ATD) medication and achievement of euthyroid or hypothyroid state were evaluated. The patient population was divided into two groups as those=>65 years and those who were younger, in order to assess the effect of age. RESULTS: Treatment success was 90% with single dose RAI therapy. Hyperthyroidism was treated in 7±7, 2 months after RAI administration. At the end of the first year, overall hypothyroidism rate was 30% and euthyroid state was achieved in 70% of patients. Age was found to be the only statistically significant variable effecting outcome. A higher ratio of euthyroidism was achieved in the geriatric patient population. CONCLUSION: High fixed dose I-131 treatment should be preferred in geriatric TNG patients in order to treat persistent hyperthyroidism rapidly. The result of this study suggests that high fixed dose RAI therapy is a successful modality in treating TNG, and high rates of euthyroidism can be achieved in geriatric patients.

Scrotal peritoneal mesothelioma on PET/CT.

Although malignant mesothelioma originating from the tunica vaginalis has been reported in the literature, direct invasion of malignant peritoneal mesothelioma to the scrotal cavity has not been described yet. Herein, we presented a diffuse malignant peritoneal mesothelioma extending inferiorly to the scrotum via inguinal canal detected on FDG PET/CT.

Marked uptake of fluorodeoxyglucose in a vocal cord after medialization: Acute and subacute positron emission tomography/computed tomography findings.

A 60-year-old male who underwent left upper lobectomy because of recently diagnosed lung cancer was admitted to the nuclear medicine department. A whole body fluorodeoxyglucose positron emission tomography/computed tomography (CT) that was performed for staging purposes, revealed an intense hypermetabolism in left vocal cord region corresponding with hyperdense mass-like material on CT scan.

Evaluation of physiological FDG uptake in the skeleton in adults: is it uniformly distributed?

AIM: The aim of this study was to study whether FDG was uniformly distributed throughout the skeleton and whether age and gender affected this biodistribution. MATERIAL AND METHODS: A total of 158 patients were included in this retrospective study. None of the patients had received prior treatment that had affected the bone marrow and patients with bone metastases, trauma, benign and/or malignant hematologic disorders were excluded from the study. The SUVmax from the 24 different locations in the skeleton was obtained and all the values were compared with each other. RESULTS: FDG uptake in the skeleton was not uniform in both sexes. While the highest FDG uptake was seen in the L3 vertebra, the lowest glucose metabolism was observed in the diaphysis of the femur. Concerning the vertebral column, FDG uptakes were also non-uniform and the SUVmax gradually increased from the cervix to the lumbar spine. The mean skeletal SUVmax was decreased in accordance with age in both genders. CONCLUSION: FDG was not uniformly distributed throughout the skeleton in both sexes. It had a tendency to increase from the appendicular to axial skeleton and from cervical to lumbar spine in the vertebral column that may be related with the normal distribution of the red bone marrow. Additionally, the glycolytic metabolism of the whole skeleton was gradually decreased in accordance with the age in both sexes.

(99m)Tc-MIBI emboli in the lungs detected on SPECT/CT: a pitfall in parathyroid scan.

Although we are familiar with artifactual, focal pulmonary F-FDG accumulations without an apparent underlying pathologic finding, similar artifact for Tc-MIBI has not been described yet. Herein, we reported incidental detection of Tc-MIBI emboli in the lungs on parathyroid SPECT/CT.

FDG PET/CT appearance of portal vein tumor thrombus in the gastric primitive neuroectodermal tumor: uncommon primary tumor site with rare finding.

Gastric primitive neuroectodermal tumor (PNET) is a very rare tumor. There are only a few case reports in the literature. Although cases with FDG uptake in the portal venous tumor thrombus (PVTT) in different primary malignancies have been evaluated before, the coexistence of PNET and PVTT has not been reported yet. Herein, we report the case of a gastric PNET with PVTT, which resolved after 3 cycles of polychemotherapy except for a residual tumor focus in the gastric corpus.

Is The Value of FDG PET/CT In Evaluating Renal Metastasis Underestimated? A Case Report And Review of The Literature.

UNLABELLED: Contrast-enhanced CT or MRI are used as a gold standard imaging modalities in the detection and characterization of renal masses. On the other hand, the role of FDG PET/CT in evaluating primary or metastatic cancers of the kidney is limited due to the excretion of FDG through urinary tract. We reported the FDG PET/CT of a lung cancer patient with multiple metastases in both kidneys which were missed in previous PET/CT, and underestimated on sequential diagnostic abdominal CT study. CONFLICT OF INTEREST: None declared.

Pitfalls in the diagnosis of thyroid dysgenesis by thyroid ultrasonography and scintigraphy.

OBJECTIVES: We aimed to investigate the reliability of thyroid ultrasonography (US) and scintigraphy in determining the type of thyroid dysgenesis (TD). METHODS: The study included 82 children (8.0±5.6 years) with a diagnosis of TD by thyroid scintigraphy with (99m)Tc and/or US. The patients were re-evaluated 6.0±5.1 years after the diagnosis. Thyroid US was performed in all cases, regardless of the previous US imaging. Scintigraphy images performed at the time of diagnoses (n=60) were re-evaluated during the study. Those who had no scintigraphy at the time of diagnosis (n=22) or had discordant findings with US (n=6) underwent a new scintigraphy. RESULTS: Scintigraphies revealed no uptake in 37, ectopia in 35, and hypoplasia in 10 cases. The sensitivity vs specificity for US to detect athyreosis, ectopia, and hypoplasia at the time of initial diagnoses was 90.5 vs 47.8, 10 vs 100, and 100 vs 80.4% respectively. The sensitivity vs specificity for scintigraphy at the time of initial diagnoses was 96.2 vs 100, 92 vs 97.1, and 100 vs 96%, respectively, for each diagnosis. Re-scintigraphy at the time of the study led to a change in the initial diagnosis of 3/6 cases. Repeated US showed disappearance of previously reported hypoplastic thyroid tissues in eight patients. CONCLUSION: US alone could not differentiate ectopia and athyreosis, whereas scintigraphy alone is also prone to mistakes in newborns and young ages. Dual thyroid imaging is important for precise structural definition of TD.

The role of dual-phase Tc-99m MIBI in the evaluation of potentially operable lesions detected by bone scanning in fibrous dysplasia: a long-term prospective follow-up study.

PURPOSE: The aim of this study was to determine the role of whole-body Tc-99m MDP bone scintigraphy (BSc) with dual-phase Tc-99m MIBI scintigraphy (DPMSc) in the assessment of fibrous dysplasia (FD) and the value of DPMSc in the detection of potentially operable lesions for guiding surgical treatment. METHODS: Twelve patients with histopathologically confirmed FD were evaluated with BSc and DPMSc. The patients were clinically followed up for a mean duration of 75 months. BSc images have been used as a guide to identify the site and the extent of the skeletal involvement. The symptomatic lesions were evaluated with DPMSc. RESULTS: Forty-three lesions were evaluated in 12 patients. BSc showed increased uptake in all of the lesions, whereas DPMSc findings correlated more accurately with the symptoms. Fifteen symptomatic lesions showed increased Tc-99m MIBI uptake on DPMSc, especially in the early phase of DPMSc. The sensitivity, specificity and accuracy values for the early phase in detecting the symptomatic lesions were 100 and 93%, and for delayed phase were 100 and 98%, respectively. CONCLUSION: BSc is useful in determining the site and extent of the skeletal involvement, especially in polyostotic FD. It seems that the potentially operable symptomatic lesions may be evaluated more accurately with DPMSc as compared with BSc. In addition, it seems that DPMSc findings correlate with the symptoms of FD, and this relationship may have a role in improving the preoperative assessment for guiding surgical treatment. DPMSc could be useful in the work-up of symptomatic patients if our results are validated in a larger patient series.