Serkan Kuyumcu

The Value of Somatostatin Receptor Imaging with In-111 Octreotide and/or Ga-68 DOTATATE in Localizing Ectopic ACTH Producing Tumors

Objective: We aimed to evaluate the value of somatostatin receptor imaging (SRI) with In-111 octreotide and Ga-68 DOTATATE in localizing ectopic ACTH producing tumors. Methods: Nineteen patients who had In-111 octreotide somatostatin receptor scintigraphy (SRS) and/or Ga-68 DOTATATE PET-CT to localize ectopic ACTH producing tumors between the years 2000 and 2012 were included retrospectively in our study. The results of SRI were compared with clinical onset, radiological findings and surgical data of the patients. Results: Sixteen In-111 octreotide SRS and five Ga-68 DOTATATE PET-CT were performed in 19 patients. In eight out of 19 patients, ectopic ACTH secretion site could be detected. In five patients, SRS showed pathologic uptake. In four of these patients, surgery revealed pulmonary carcinoid tumors and in one patient pancreatic neuroendocrine tumor. In one patient, Ga-68 DOTATATE PET-CT revealed pathologic uptake in lung nodule which came out to be pulmonary carcinoid tumor. In another patient who had resection of metastases of atypical carcinoid tumor prior to scans, new metastatic foci were detected both with SRS and Ga-68 DOTATATE PET-CT imaging. In one patient, although SRS was negative, CT which was performed three years later showed a lung nodule diagnosed as pulmonary carcinoid tumor. In 11 patients, ectopic ACTH secretion site could not be detected. In 10 of those patients, scintigraphic and radiological imaging did not show any lesions and in one patient, Ga-68 DOTATATE PET-CT was false positive. Conclusion: SRI has a complementary role with radiological imaging in localizing ectopic ACTH secretion sites. PET-CT imaging with Ga-68 peptide conjugates is a promising new modality for this indication. Conflict of interest:None declared.

Diagnostic spectrum of congenital hypothyroidism in Turkish children

Background:  Congenital hypothyroidism (CH) is classified as transient or permanent. Transient CH can be treated with short‐term thyroxine replacement therapy or followed up without therapy, whereas lifelong thyroxine replacement is needed in permanent CH. Determination of the underlying etiology is essential for determination of follow‐up strategy. The purpose of the present study was therefore to assess the role of color Doppler ultrasonography (CDU) in etiologic diagnosis of CH together with radionuclide method and grayscale ultrasonography (GSU).

Hepatic adenomatosis may mimic metastatic lesions of liver with 18F-FDG PET/CT.

Hepatic adenomatosis is an uncommon benign neoplasm, with the presence of multiple adenomas (generally more than 4) within the liver. A 52-year-old woman presented with multiple (>10) solid liver lesions detected with abdominal ultrasonography and verified with magnetic resonance imaging (MRI). Subsequently, F-18 FDG PET/CT demonstrated increased uptake in these lesions. Histology revealed hepatic adenomatosis. F-18 FDG PET/CT cannot reliably differentiate hepatic adenomas from malignant processes on the basis of uptake.

Comparison of 68Ga-DOTATATE PET-CT, 18F-FDG PET-CT and 99mTc-(V)DMSA scintigraphy in the detection of recurrent or metastatic medullary thyroid carcinoma

PurposeWe aimed to compare the efficacies of gallium-68 (68Ga) DOTATATE PET-computed tomography (CT), fluorine-18 fluorodeoxyglucose (18F-FDG) PET-CT and technetium-99m (99mTc)-(V)DMSA scintigraphy in the detection of residual/metastatic medullary thyroid carcinoma (MTC). Materials and methodWe retrospectively evaluated DOTATATE PET-CT, 18F-FDG PET-CT and (V)DMSA scintigraphy of 22 MTC patients, all taken within a 6-month period in each patient, because of high levels of calcitonin (Ct) and carcinoembryonic antigen (CEA). We investigated the relationships between the results of the imaging modalities and tumour marker levels and the sporadic versus hereditary nature of the disease, as well as the effect of imaging results on patient management. ResultsThe ages of the patients at diagnosis were between 20 and 69 years. The median levels of Ct and CEA were 871.5 pg/ml and 11.2 ng/ml, respectively. In the patient-based analysis, we observed at least one focus of abnormal uptake in 15 of 22 DOTATATE PET-CT (68.2% sensitivity), eight of 18 18F-FDG PET-CT (44.4% sensitivity) and five of 15 (V)DMSA scans (33.3% sensitivity). These data showed a significant difference between DOTATATE PET-CT and (V)DMSA scintigraphy (P=0.016), whereas the relationships between DOTATATE PET-CT and 18F-FDG PET-CT and between 18F-FDG PET-CT and (V)DMSA scintigraphy showed no significant differences (P>0.05). In the lesion-based analysis, 134 lesions were detected with DOTATATE PET-CT, 76 lesions with 18F-FDG PET-CT and nine lesions with (V)DMSA scintigraphy. ConclusionDOTATATE PET-CT is an efficient imaging modality in MTC patients with increased Ct and CEA (especially >1000 pg/ml and 50 ng/ml, respectively) for localizing recurrent or metastatic disease. 18F-FDG PET-CT can be performed if DOTATATE PET-CT is not available, but (V)DMSA scintigraphy is not recommended.

Impact of Nonosseous Findings on 18F-NaF PET/CT in a Patient with Ductal Breast Carcinoma

Abstract18F-NaF was used as a bone-seeking PET tracer for skeletal imaging until the introduction of the widely available 99mTc-labeled bone agents. However, there is renewed clinical interest in 18F-NaF since prior technical and logistic limitations to its routine use are no longer present, and, as a consequence, it is likely that uptake unrelated to bone and non-osseous findings will be encountered more frequently. As a result of tumoral necrosis, soft tissue metastases may demonstrate 18F-NaF avidity due to dystrophic calcification. On the other hand, all non-osseous findings, whether 18F-NaF avid or not, may provide important diagnostic information that may alter the course of the disease, including treatment options. Herein we present a patient with ductal carcinoma of the breast in whom findings unrelated to the skeletal system in 18F-NaF PET/CT altered the treatment strategy.

Microscopic polyangiitis on 18F-FDG PET/CT of a patient with fever of unknown origin presenting as isolated diffuse renal hypermetabolism

We report on a case of fever of unknown origin (FUO) in which F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT assisted in depicting renal inflammation and eventually led to a histologically confirmed diagnosis of microscopic polyangiitis (MP). MP is an autoimmune disease characterized by systemic necrotizing, small-vessel vasculitis without clinical or pathological evidence of necrotizing granulomatous inflammation. The kidneys, skin, joints, muscles, peripheral nerves and gastrointestinal tract are the most commonly affected organs. Evidence supporting the pivotal role of FDG PET in the diagnosis of FUO is increasing steadily [1]. It has also proven to be a valuable imaging technique in diagnosing and determining the extent of vasculitis [2]. This case illustrates the role of FDG PET in the diagnosis of FUO by localizing sites of active inflammation due to vasculitis and guiding the selection of biopsy site. A 45-year-old man who presented with fever, weight loss and elevated serum C-reactive protein (CRP) level was indicated for F-FDG PET/CT due to FUO. FFDG PET/CT revealed diffuse increased FDG uptake (a) in bilaterally enlarged kidneys (b) with a maximum standardized uptake value (SUVmax) of 27.2 (c). No additional pathological FDG uptake was observed (d). The interpretation suggested either lymphoma which has been reported before [3] or inflammation due to autoimmune diseases. Histopathological examination revealed no pathological change in the glomeruli but predominant polyclonal plasmacytic infiltration (e) in the interstitium with focal necrotic areas with central cellular debris and abscess formation (f). All findings suggested MP with supporting clinical data.

Role of red blood cell scintigraphy for determining the localization of gastrointestinal bleeding.

BACKGROUND We aimed to evaluate the role of Tc-99m labeled red blood cell (RBC) scintigraphy for determination of localization of gastrointestinal system (GIS) bleeding. METHODS Fifty-seven cases (27 females, 30 males; mean age 43.9±24; range 1 to 91 years) who referred to our clinic between 1995-2010 were evaluated for determination of localization of GIS bleeding with RBC scintigraphy. Prior to scintigraphy, gastroscopy in 51, colonoscopy in 45, and angiography in 9 patients were performed. RESULTS RBC scintigraphies were positive and negative in 31 and 26 patients, respectively. Positive scintigraphic findings were obtained within the 1st hour of dynamic imaging in 19 patients, within the 1st-4th hour static images in 7, and within the 4th-24th hour images in 5 patients. Fourteen patients underwent surgical exploration. In 13 patients, the surgery confirmed the diagnosis by RBC scintigraphy (accuracy: 92.8%). Of 43 patients without surgical exploration, 12 had anemia due to iron deficiency and their scintigraphic evaluation were negative. Four patients died and in 27 patients, GIS bleeding ceased spontaneously or with conservative measures. CONCLUSION Scintigraphy should be the primary tool for accurate diagnosis of patients with active GIS bleeding. Positive dynamic images obtained within the first hour of imaging may be more accurate for demonstrating bleeding localization and a good predictor of requirement of surgical exploration.

Neuroendocrine Tumor Diagnosis and Management: 68Ga-DOTATATE PET/CT

OBJECTIVE The purpose of this article is to provide a review of the use of 68Ga tetraazacyclododecanetetraacetic acid-DPhe1-Tyr3-octreotate (DOTATATE) PET/CT, a functional imaging modality for assessment of well-differentiated neuroendocrine tumors (NETs). It has become the preferred imaging modality for initial diagnosis, selection of patients for peptide receptor radionuclide therapy, and localization of unknown primary tumors. The National Comprehensive Cancer Network guideline has added 68Ga-DOTATATE PET/CT as an appropriate test in the management of NETs. CONCLUSION In combination with FDG PET/CT, 68Ga-DOTATATE PET/CT can noninvasively assess tumor heterogeneity, especially in G2 and G3 NETs, for personalized management of patients.

Correlation of 18F-FDG PET/CT with pathological features and survival in primary breast cancer

Objective The aim of this study was to determine the correlation between the primary tumor (PT) maximum standardized uptake value (SUVmax) and breast cancer prognostic factors, overall survival, and relapse-free survival on the basis of histopathological and molecular characteristics. Patients and methods In this retrospective study, 436 female patients with breast cancer were evaluated following a pretreatment 18F-FDG PET/CT scan. The PT SUVmax and histopathological/molecular characteristics were determined from primary tumor tissues and analyzed using the Mann–Whitney U and Kruskal–Wallis tests. Results The median SUVmax of 436 PT was 10.1 (1.7–72). The PT SUVmax values were higher in ER− versus ER+ (P=0.001), PR− versus PR+ (P=0.001), Her2+ versus Her2− (P=0.01), Ki-67% of at least 20 versus Ki-67% of less than 20 (P<0.001), histological grade 3 versus grade 1–2 (P<0.001), nuclear pleomorphism score 3 versus score 1–2 (P<0.001), and mitotic score 3 versus score 1–2 patients (P<0.001). The lowest SUVmax levels were observed in the LumA group and the highest SUVmax levels were observed in the Her2 group (P<0.001). LumA patients with PR values greater than 20% had lower PT SUVmax values than the patients with PR values of 20% or less (P=0.023). The PT SUVmax was higher in patients with recurrence (P=0.03) and died related to disease (P<0.001) independent of time. Conclusion The PT SUVmax showed a significant correlation with most of the prognostic factors and histopathological subtypes as a noninvasive tool. It is also usable in the prediction of tumor-related deaths or relapse independent of time. Our results could guide future studies to provide new histopathologic subtype definitions on the basis of new PR criteria.

An Incidental Solitary Plasmacytoma of Bone Mimicking Neuroendocrine Tumor Metastasis on 68Ga-DOTATATE Positron Emission Tomography/Computed Tomography

A 54-year-old woman with suspicion of neuroendocrine tumor (NET) was referred for 68Ga-DOTATATE positron emission tomography/computed tomography (CT) imaging due to clinical findings. A well-defined osteolytic lesion on the corpus of the third lumbar vertebra was evident on CT images with mild uptake of 68Ga-DOTATATE, which led to suspicion of NET metastasis. Histopathologic examination revealed solitary plasmacytoma of the bone. The patient received local external radiotherapy for plasmacytoma. This case indicatesthat other diseases expressing somatostatin receptors may be inaccurately reported as tumor recurrence and highlights the importance of meticulous evaluation of positive findings.