68Ga-Prostate-Specific Membrane Antigen Uptake as a Surrogate Biomarker of Neovascularity in Hepatocellular Carcinoma.

68Ga-prostate-specific membrane antigen (68Ga-PSMA) is expressed in the endothelium of tumor-associated neovasculature of various solid malignancies possibly due to tumor-associated angiogenic factors and endothelial cell sprouting. We report a case of a 45-year-old man with known colorectal cancer, cirrhosis, and hepatitis C. Contrast-enhanced computed tomography (CT) showed a hypervascular lesion in the liver, and 18F-fluorodeoxyglucose positron emission tomography (PET) did not show any suspicious hepatic uptake. 68Ga-PSMA PET-CT showed predominantly heterogeneous perilesional uptake in a configuration similar to the arterial enhancement pattern on the diagnostic CT. 68Ga-PSMA uptake in hepatocellular carcinoma appears to be primarily neoangiogenesis driven, and its morphological and functional characterization can subsequently influence the selection of anti-neoangiogenic chemotherapy agents as well as guiding radionuclide ligand therapy.

COVID-19 Vaccination Manifesting as Incidental Lymph Nodal Uptake on 18F-FDG PET/CT.

ABSTRACT: Benign uptake on 18F-FDG PET can be seen with inflammatory conditions. We report a case of an 86-year-old woman with successfully treated nasal melanoma who underwent routine follow-up 18F-FDG PET, day 6 after the second dose of Pfizer-BioNTech COVID-19 vaccine inoculated in the left deltoid muscle. 18F-FDG PET showed increase tracer uptake in the left deltoid muscle and in 2 normal-sized left subpectoral nodes. These findings were considered secondary to vaccination. With the current drive of global COVID-19 immunization, this case highlights the importance of documenting vaccination history at the time of scanning to avoid false-positive results.

Incidental brain metastasis of breast cancer detected on 18F-Sodium Fluoride (NaF) PET-CT.

18F- Sodium Fluoride (NaF) is an excellent bone imaging agent used for skeletal staging but can also be localized in extra osseous calcifying lesions. We report a case of a 38-year-old woman with breast carcinoma referred for 18F-NaF PET-CT to evaluate possible metastatic lesions. 18F-NaF PET-CT detected incidental focal soft tissue tracer uptake in the right cerebellum with no sign of calcification seen on CT images. Subsequent MRI show high intensity signal lesion confirming brain metastasis. Extra osseous 18F-NaF uptake may provide important diagnostic information that might alter patient management.

A Very Unusual Pattern of Intraperitoneal and Extraperitoneal Heterotropic Splenic Tissue-Mimicking Metastases Identified on 68Ga-DOTA-NOC Positron Emission Tomography/Computed Tomography and 99mTc Heat-denatured Erythrocyte Study.

The dissemination and autotransplantation of viable splenic tissue in different anatomic compartments of the body can present a diagnostic dilemma, especially when metastatic disease is suspected. We report a case of a 30-year-old male with well-differentiated gastric neuroendocrine tumor (Grade II) treated with surgery. Follow-up 68Ga-DOTA-NOC demonstrated a suspicious peritoneal soft-tissue nodule in the right paracolic gutter with increased tracer uptake. In view of splenectomy 10 years ago, the patient underwent 99mTc heat-denatured erythrocyte study which showed a very unusual pattern of multiple tracer-avid foci of splenic tissue in both intraperitoneal and extraperitoneal distributions. The integration of the patient's history and complementary nuclear imaging results led to the correct diagnosis of splenosis.

Talocalcaneal Coalition With Os Sustentaculum: Rare Cause for Foot Pain Demonstrated on 99mTc-HDP SPECT/CT.

Os sustentaculi is a rare accessory bone of the foot located along the posterior end of sustentaculum tali. It is a component type of extra-articular talocalcaneal coalition. We report the case of a 17-year-old boy with symptomatic os sustentaculum with talocalcaneal coalition diagnosed on Tc-HDP SPECT/CT. We wish to emphasize on the use of SPECT/CT in not only characterizing the ossicle morphologically, but also for evaluation of this anatomical variant as an active source of pain in the absence of a more common cause of pain in young physically active patients.

Extensive Extramedullary Hematopoiesis in Thalassemia: Soft Tissue Uptake on 99mTc-MDP SPECT/CT.

We report the case of a 45-year-old man with thalassemia major referred for a bone scan as a workup for generalized bone pain. Tc-MDP SPECT CT showed multiple elongated soft tissue masses along the inner aspects of ribs and along both sides of dorsal spine with calcification and mild tracer uptake. There was also a large lobulated presacral soft tissue mass displacing the bladder and involving the adjacent pelvic bone. Biopsy of mildly avid tracer uptake in pelvic soft tissue mass was extramedullary hematopoiesis confirmed by biopsy.

Spectrum of false positive 18F-sodium fluoride (NaF) bone PET/CT findings in Oncology imaging; A narrative pictorial review of cases from a single institution.

Fluorine-18-sodium fluoride (18F-NaF) is a positron emission tomography (PET) bone imaging agent mainly used for oncology staging but may also be used in the evaluation of benign bone and joint pathology conditions. Fluorine-18-NaF is an excellent bone-seeking agent with high bone uptake owing to favorable biodistribution with rapid single-pass extraction, limited plasma protein binding and prompt renal clearance. Fluorine-18-NaF PET/computed tomography (CT) is highly sensitive in identifying both sclerotic and lytic bone metastatic lesions. Occasionally 18F-NaF uptake in benign bone lesions can mimic malignantpathology. In these cases, the pattern of 18F-NaF uptake may elicit a specific diagnosis and correlation with clinical information and morphological information from correlative CT is essential for a correct diagnosis. In the present article, we present a series of clinical cases demonstrating examples of 18F-NaF uptake in benign lesions which can simulate malignant pathology in patients undergoing cancer staging.