Abstract We describe a rare case of metastatic prostate carcinoma to the heel. Bone scintigraphy revealed high uptake simulating fractures. Standard PSMA PET/CT was negative. As PSA elevated, extended field-of-view PET/CT revealed ankle uptake with virtually identical spatial distribution and intensity of both tracers. Histopathology confirmed ankle metastases of prostate carcinoma, which retrospectively was the inaugural manifestation of the metastatic skeletal disease. This case highlights the need to consider peripheral limb bone metastases in patients with biochemical recurrence. In case of focal symptoms or unexplained bone scan findings, the PSMA acquisition coverage should be extended to include the respective body part.

Primary tumors of the penile corpus spongiosum are rare. Hereby we describe the scintigraphic findings of a case of penile leiomyoma within the corpus spongiosum tissue, which was incidentally detected on FDG PET/CT. The benign neoplasm was growing in close proximity to the urethra showing increased focal FDG uptake on sequential PET/CT studies. Subsequently, the patient experienced obstructive urinary symptoms, and the tumor was resected. We concluded that the possibility of neoplasm should be kept in mind while evaluating a patient with persistent focal penile FDG uptake, which may be the first and only manifestation of the disease.

Abstract Simultaneous occurrence of multiple meningiomas of the spine appearing at different neuroaxial levels is extremely rare event. We present the scintigraphic findings of incidentally detected multiple meningiomas of the spine on 68Ga-DOTATATE PET/CT during the evaluation of a patient with pulmonary carcinoid tumor. These scintigraphic findings could result in a “false-positive” interpretation by exhibiting highly increased uptake similar to that of metastases of neuroendocrine neoplasm. Nuclear medicine physicians should be aware of this potential pitfall in somatostatin receptor imaging to prevent misinterpretation.

Abstract Radioiodine whole-body scintigraphy has long been used for detection of differentiated thyroid carcinoma with high avidity in functioning thyroid tissues. However, uptake is not completely specific, and “false-positive” uptake in nonthyroidal tumors have rarely been reported. Herein, we present a case of incidentally detected neuroendocrine tumor showing high radioiodine uptake initially suspected to be thyroid metastasis. Correlative imaging with FDG PET/CT and 68Ga-DOTATATE PET/CT is presented, and literature survey is discussed. We conclude that neuroendocrine tumor should be added to the reported list of neoplasms that can show “false-positive” uptake representing a potential interpretative pitfall.

ABSTRACT:Radioiodine whole-body scintigraphy has long been used for detection of differentiated thyroid carcinoma with high avidity in functioning thyroid tissues. However, uptake is not completely specific, and "false-positive" uptake in nonthyroidal tumors have rarely been reported. Herein, we present a case of incidentally detected neuroendocrine tumor showing high radioiodine uptake initially suspected to be thyroid metastasis. Correlative imaging with FDG PET/CT and 68 Ga-DOTATATE PET/CT is presented, and literature survey is discussed. We conclude that neuroendocrine tumor should be added to the reported list of neoplasms that can show "false-positive" uptake representing a potential interpretative pitfall.

INTRODUCTION:In recent years, nuclear medicine has become a diverse and central profession that influences the diagnosis and treatment of patients with diseases from all fields of medicine. Imaging through nuclear medicine is a significant step in the process of making therapeutic decisions and evaluating patients with malignancy, infectious or inflammatory process, heart problems, neurological disorders and more. The advantages of diagnostic methods from the field of nuclear medicine arise from their non-invasiveness and from the possibility of providing functional and metabolic information at a very early stage during the course of the disease. In the last two decades, hybrid imaging devices, PET-CT (positron emission tomography (PET)-computed tomography (CT)) and then SPECT-CT (single-photon emission computerized tomography (SPECT) - computed tomography (CT)) and PET-MRI (positron emission tomography (PET)- magnetic resonance imaging (MRI)) have been developed. Thereby, the field has undergone a major revolution accompanied by a significant increase in the volume of scans thanks to the improved diagnostic accuracy possible with the latest imaging devices. Recently, another breakthrough has occurred with the successful implementation of a unique method of treatment in nuclear medicine, Theranostics. This is just the beginning. More accurate and faster digital imaging devices have been developed with the ability to reduce patient exposure to radiation, state-of-the-art molecular imaging markers have been developed and new theranostics medications are being developed. Along with the development of artificial intelligence tools, further significant changes are expected to take place in this high-tech field. The main purpose of the review is to provide a source of information to the reading public, even if they are unfamiliar with the subject, for innovations in this field and demonstrating the role of nuclear medicine in diagnosing a number of diseases and planning personalised medical treatment for patients with a view on nuclear medicine in Israel.

A 68-year-old man underwent F-18-prostate-specific membrane antigen (PSMA) PET/CT for staging of a newly diagnosed prostate adenocarcinoma. Unexpectedly, PET/CT revealed high focal F-18-PSMA brain uptake, which initially was suspected for a brain metastasis. Corresponding CT and MRI scans revealed characteristic imaging features of an intracranial dermoid cyst at this site. This is an exceptional location for a dermoid cyst, which had been followed up conservatively with no substantial changes. This case shows that dermoid cyst should be added to the reported list of benign neoplasms that shows "false-positive" PSMA uptake during evaluation of patients with prostate carcinoma, representing a potential interpretative pitfall.

A 76-year-old man with a prior medical history of resected malignant melanoma of the skull underwent Ga-prostate-specific membrane antigen (PSMA) PET/CT due to rising tumor markers of a known prostate carcinoma. Unexpected high Ga-PSMA brain uptake was encountered around the surgical cavity in the skull with initially no specific structural changes on anatomical imaging. Successive CT and MRI eventually revealed local melanoma brain recurrence at this site. This interesting case demonstrates the diagnostic potential of Ga-PSMA PET/CT imaging for detection of malignant melanoma brain recurrence.

A 32-year-old woman was treated for breast carcinoma. Posttreatment FDG PET/CT scan revealed complete response, but in the contralateral breast, unexpected incidental intense FDG uptake was seen with a differential diagnosis of both malignant and benign causes. Medical history revealed recent breast contusion. The lesion was further evaluated by mammogram and ultrasound, which were compatible with deep breast bruise. Histopathology showed no malignancy. Subsequent FDG PET/CT study showed breast uptake normalization. This case shows that postcontusion breast hematoma can cause a potential pitfall mimicking breast malignancy on FDG PET/CT.

Medullary thyroid cancers (MTC) are neuroendocrine tumors of thyroid parafollicular C cells, which account for 5% to 10% of all thyroid cancers. The C cells secrete different types of peptides and hormones with calcitonin being the most common. Increased calcitonin levels confirm the diagnosis of MTC and are used in the follow-up of patients longitudinally for recurrence. Normal calcitonin values are less than 5 pg/mL in women and below 8.5 pg/mL in men. Calcitonin directly inhibits bone resorption and quickly promotes renal excretion of calcium, leading to a decrease in serum calcium 2 hours after administration.

ObjectiveThe objective of this report is to present an unusual case of intramedullary spinal cord metastasis (ISCM) as the presenting feature of papillary thyroid carcinoma (PTC).MethodsThe presented case includes clinical, biochemical, and imaging findings as well as surgical and pathology reports. Treatment with radioactive iodine (RAI) and the response to this treatment are presented.ResultsA 71-year-old woman was evaluated for debilitating low back pain and walking disability. Magnetic resonance imaging demonstrated an oval, lumbar, intramedullary mass with benign features and surgery was scheduled. On preoperative evaluation for the lumbar mass, a multinodular thyroid goiter (unfortunately overlooked previously) was noticed, causing severe narrowing of the trachea. Total thyroidectomy was performed with a pathology diagnosis of PTC. In a second operation, the lumbar lesion was removed and proved to represent metastatic PTC. External beam radiation was subsequently administered to the thyroid bed, lumbar spine, and other skeletal metastases, followed by 150 milliCurie of RAI. A post-treatment scan showed high uptake over the lumbar spine, and skeletal and lung lesions. Clinically, the patient restored her walking ability and back pain improved.ConclusionISCM rarely is the presenting feature of PTC. Our patient presented with back pain which is the typical, though non-specific symptom, of ISCM. She showed good clinical response to multimodal treatment which is in line with the few other differentiated thyroid cancer patients with ISCM reported in the literature. Prompt surgical resection, followed by external beam radiation and RAI, may improve neurological signs, alleviate pain, and improve quality of life.

Epithelioid hemangioendothelioma is a rare low- to intermediate-grade malignant vascular neoplasm with a variable clinical course and currently no standardized treatment. We present a case of a 65-year-old woman diagnosed as having mediastinal epithelioid hemangioendothelioma, a location which is very exceptional. FDG PET/CT was more sensitive than CT for staging, revealing intense FDG uptake in the primary tumor and in the metastatic disease. Despite high FDG uptake, the disease was stable with no further specific treatment. Only few reports utilizing FDG PET/CT are available; review of the literature on this subject is included.

Ga-DOTATATE imaging is commonly used for the detection of metastatic disease in neuroendocrine tumors. We present a case of a 69-year-old woman postsurgery for lung carcinoid tumor in which sequential follow-up Ga-DOTATATE PET/CT studies identified focal hepatic uptake that was presumed to represent a liver metastasis. However, correlative imaging with MRI revealed a focal fatty sparing of the liver composed of benign hepatic parenchyma at that area accompanied with diffuse liver steatosis in the background of the "pseudolesion." This report demonstrates a potential "false-positive" hepatic finding that can strikingly mimic a metastasis in neuroendocrine tumor imaging.

A 64-year-old man was treated with multiagent chemotherapy owing to high-grade non-Hodgkin lymphoma presenting as a bulky disease involving the spleen. Interim and posttreatment sequential FDG PET/CT scans revealed a residual splenic mass showing markedly intense FDG uptake suspected of a residual viable lymphoma. To definitely decide about the appropriate treatment, a laparoscopic splenectomy was performed. Histopathologic specimen was compatible with the rare diagnosis of postchemotherapy histiocyte-rich pseudotumor of the spleen, a potential pitfall simulating viable disease on FDG PET/CT.

Abstract As with any new molecular imaging modality, accurate characterization of abnormalities on 68Ga-PSMA PET/CT imaging can be accomplished only if one is aware of the normal distribution pattern, physiological variants, and potential sources of false imaging findings. Altered biodistribution can have a significant impact on scan interpretation. Presented here is a rare case in which radiopharmaceutical radiolysis occurred causing excessive free 68Ga-citrate showing as an increased vascular activity. As 68Ga-PSMA PET/CT imaging is a relatively new imaging technique, it is important to be aware of such a potential technical pitfall in clinical practice in order to prevent scan misinterpretation.

Utilizing the publicly available neuroimaging database enabled by Alzheimer’s disease Neuroimaging Initiative (ADNI; http://adni.loni.usc.edu/ ), we have compared the performance of automated classification algorithms that differentiate AD vs. normal subjects using Positron Emission Tomography (PET) with fluorodeoxyglucose (FDG). General linear model, scaled subprofile modeling and support vector machines were examined. Among the tested classification methods, support vector machine with Iterative Single Data Algorithm produced the best performance, i.e., sensitivity (0.84) × specificity (0.95), by 10-fold cross-validation. We have applied the same classification algorithm to four different datasets from ADNI, Health Science Centre (Winnipeg, Canada), Dong-A University Hospital (Busan, S. Korea) and Asan Medical Centre (Seoul, S. Korea). Our data analyses confirmed that the support vector machine with Iterative Single Data Algorithm showed the best performance in prediction of future development of AD from the prodromal stage (mild cognitive impairment), and that it was also sensitive to other types of dementia such as Parkinson’s Disease Dementia and Dementia with Lewy Bodies, and that perfusion imaging using single photon emission computed tomography may achieve a similar accuracy to that of FDG-PET.

Osteotoxic effect is a common adverse effect of chemotherapy for childhood acute lymphoblastic leukemia. The pathophysiology of impaired bone growth is multifactorial and can affect both osteoblast and osteoclast function. Significant contribution in affecting skeletal metabolism belongs to high-dose corticosteroid treatment. We present the case of a 12-year-old adolescent girl who was treated for high-risk pro-B acute lymphoblastic leukemia. The Tc-MDP bone scan, as a sensitive indicator of osteoblastic activity, shows that growth plate inhibition after intensive treatment may be temporary and reversible.

An 80-year-old man with suspected recurrent prostate carcinoma underwent Ga-PSMA PET/CT, which showed enlarged axillary lymph nodes with intensely increased Ga-PSMA uptake, an atypical site for prostate cancer metastasis. Fine-needle aspiration biopsy revealed metastatic malignant melanoma. FDG PET/CT revealed congruent intense FDG uptake. Therefore, malignant melanoma should be included in the list of malignancies that can be seen positive on Ga-PSMA PET/CT. In unclear Ga-PSMA PET-positive lesions, further clarification with other imaging techniques or biopsy is mandatory to avoid scan misinterpretation. Review of the literature revealed other non-prostate cancer causes of elevated PSMA uptake classified into neoplastic and nonneoplastic conditions.

A 20-year-old man with gastrointestinal symptoms and weight loss underwent FDG PET/CT, which revealed multiple hypermetabolic hepatic lesions concerning for metastatic liver disease. The outcome of liver biopsy was consistent with the diagnosis of peliosis hepatis which is a rare benign disease characterized by multiple blood-filled cystic spaces in the hepatic parenchyma. The findings of peliosis on FDG PET/CT are not well reported in the literature. These interesting images emphasize the importance of including peliosis hepatis in the differential diagnosis of multiple hypermetabolic hepatic lesions on FDG PET/CT, which could simulate malignancy.