Microcalcified Hepatic Metastases Incidentally Detected on F-18 NaF PET/CT in a Patient with Prostate Cancer.

F-18 NaF PET/CT evaluation has gained importance in recent years. Achievements from F-18 NaF PET/CT are: higher sensitivity of positron imaging, higher target background ratio with higher tracer accumulation in bone hydroxyapatite and higher specificity through CT correlation. These properties have also given directions to new research fields based on imaging microcalcifications, very recently. A limited number of cases have reported the F-18 NaF uptake in macrocalcified soft tissue metastases. Although the presence of microcalcification was not proved; accumulation of F-18 NaF in the metastatic brain lesion with no visible calcification on the CT, in a patient with ductal breast carcinoma has also been reported. Herein we present a patient with microcalcified hepatic metastasis of prostate cancer incidentally detected on F-18 NaF PET/CT which was confirmed with histochemical staining.

Primary Pulmonary Lymphoepithelioma-like Carcinoma on FDG PET/CT.

A 69-year-old male smoker was referred to 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) with the indication of a suspicious solitary pulmonary nodule. FDG PET/CT determined a 2.5 × 2-cm soft-tissue lesion (SUVmax, 16.2) with spiculated margins in the hilum of the right lung. A 1-cm diameter lymphadenopathy on the right hilum with an SUVmax of 3.2 was also determined. Transbronchial biopsy of the right hilar lymphadenopathy did not reveal any malignant features in histopathologic examination, and it was determined to be reactive. The patient underwent a right upper lobe segmentectomy, and the histopathologic evaluation revealed that the tumor was a primary lymphoepithelioma-like carcinoma (LELC) of the lung with negative Epstein-Barr virus (EBV) on in situ hybridization studies. In this case report, we mainly focus on the FDG avidity of this very rare kind of tumor comparatively with previous reports and possible explanations of discordancy in FDG avidity in relation to histopathologic characteristics.

Diffusely Increased Splenic Fluorodeoxyglucose Uptake in Lung Cancer Patients.

OBJECTIVES: This study aimed to investigate the association of diffuse splenic F-18 fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT) with tumor maximum standardized uptake value (SUVmax), presence of distant metastases, and hematological and inflammatory parameters. MATERIAL AND METHODS: Initial FDG PET/CT of 15 lung cancer patients with diffuse splenic FDG uptake were retrospectively analyzed (Group 1). Twelve patients who recently underwent FDG PET/CT for histopathologically proven lung cancer were enrolled as the control group (Group 2). All 27 patients had hematological data, including C-reactive protein (CRP) level, within 5 days before or after PET/CT. To determine SUVmax, the region of interests included the tumor, liver, spleen, and iliac crest. The possible associations between the spleen/liver (S/L) and bone marrow/liver (BM/L) ratios and tumor SUVmax, presence of metastasis, and hematological parameters were evaluated. RESULTS: The S/L ratio and hemoglobin (Hb) levels were different between the two groups (p=0.000 and 0.05, respectively). The number of patients with anemia were significantly higher in Group 1 than in Group 2 (p=0.02). Although mean Hb levels were different between the two groups, there was no correlation between Hb levels and S/L ratios. There was no significant difference between the two groups with respect to the numbers of patients who had an accompanying infection site. Only CRP levels were correlated with S/L ratios in Group 1 among various other parameters (r=0.559, p=0.05). CONCLUSION: Our results suggested that inflammation degree correlated with increased splenic FDG uptake in lung cancer patients and was enhanced by anemia. Systemic inflammation and anemia could be important causes of diffusely increased splenic FDG accumulation on PET/CT examinations of lung cancer patients.

Incidental Detection of Subcutaneous Myopericytoma of Trunk on FDG PET/CT and Bone Scintigraphy for Imaging of Colon Cancer.

Myopericytoma is a rare type of unusual soft tissue tumor with perivascular myoid differentiation. A 53-year-old man with the diagnosis of colon cancer was referred to Tc-MDP bone scan and F-FDG PET/CT for staging. A subcutaneous mass located in right lower back with heterogeneous FDG uptake was detected on PET/CT. There was increased osteoblastic activity on MDP bone scan in the same region. Mass was resected and subsequently confirmed as myopericytoma by histopathology.

Splenic infarction as a pitfall on labeled red blood cell imaging.

Patient with a history of overt gastrointestinal bleeding, diabetes mellitus, hypertension, polycythemia vera, and choledocojejunostomy was hospitalized because of hematemesis and melena. An area of Technetium-99m labeled red blood cells accumulation at the splenic flexure similar to an overt bleeding area, was observed on gastrointestinal bleeding scintigraphy (GIBS). In case of underlying malignancy, abdominal computed tomography was performed and demonstrated the infarction area placed laterally in spleen, appearing as a cold region on sctintigraphic image, separating the inferomedial and upper part of splenic uptake. Splenic variants and pathologies can complicate interpretation of GIBS.

Correction of differential renal function for asymmetric renal area ratio in unilateral hydronephrosis.

OBJECTIVE: Children with unilateral hydronephrosis are followed up with anteroposterior pelvic diameter (APD), hydronephrosis grade, mercaptoacetyltriglycine (MAG-3) drainage pattern and differential renal function (DRF). Indeterminate drainage preserved DRF in higher grades of hydronephrosis, in some situations, complicating the decision-making process. Due to an asymmetric renal area ratio, falsely negative DRF estimations can result in missed optimal surgery times. This study was designed to assess whether correcting the DRF estimation according to kidney area could reflect the clinical situation of a hydronephrotic kidney better than a classical DRF calculation, concurrently with the hydronephrosis grade, APD and MAG-3 drainage pattern. MATERIALS AND METHODS: We reviewed the MAG-3, dimercaptosuccinic acid (DMSA) scans and ultrasonography (US) of 23 children (6 girls, 17 boys, mean age: 29 ± 50 months) with unilateral hydronephrosis. MAG-3 and DMSA scans were performed within 3 months (mean 25.4 ± 30.7 days). The closest US findings (mean 41.5 ± 28.2 days) were used. DMSA DRF estimations were obtained using the geometric mean method. Secondary calculations were performed to correct the counts (the total counts divided by the number of pixels in ROI) according to kidney area. The renogram patterns of patients were evaluated and separated into subgroups. The visual assessment of DMSA scans was noted and the hydronephrotic kidney was classified in comparison to the normal contralateral kidney's uptake. The correlations of the DRF values of classical and area-corrected methods with MAG-3 renogram patterns, the visual classification of DMSA scan, the hydronephrosis grade and the APD were assessed. RESULTS: DRF estimations of two methods were statistically different (p: 0.001). The categories of 12 hydronephrotic kidneys were changed. There were no correlations between classical DRF estimations and the hydronephrosis grade, APD, visual classification of the DMSA scan and uptake evaluation. The DRF distributions according to MAG-3 drainage patterns were not different. Area-corrected DRF estimations correlated with all: with an increasing hydronephrosis grade and APD, DRF estimations decreased and MAG-3 drainage patterns worsened. A decrease in DRF (< 45 %) was determined when APD was ≥ 10 mm. When APD was ≥ 26 mm, a reduction of DRF below 40 % was determined. CONCLUSION: Our results suggest that correcting DRF estimation for asymmetric renal area ratio in unilateral hydronephrosis can be more robust than the classical method, especially for higher grades of hydronephrotic kidneys, under equivocal circumstances.