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Abstract Background 18F-fluoro-deoxy-glucose (18 F-FDG) positron emission tomography integrated/combined with computed tomography (PET-CT) provides the best diagnostic results in the metabolic characterization of undetermined solid pulmonary nodules. The diagnostic performance of 18 F-FDG is similar for nodules measuring at least 1 cm and for larger masses, but few data exist for nodules smaller than 1 cm. Case presentation We report five cases of oncologic patients showing focal lung 18 F-FDG uptake on PET-CT in nodules smaller than 1 cm. We also discuss the most common causes of 18 F-FDG false-positive and false-negative results in the pulmonary parenchyma. In patient 1, contrast-enhanced CT performed 10 days before PET-CT did not show any abnormality in the site of uptake; in patient 2, high-resolution CT performed 1 month after PET showed a bronchiole filled with dense material interpreted as a mucoid impaction; in patient 3, contrast-enhanced CT performed 15 days before PET-CT did not identify any nodules; in patients 4 and 5, contrast-enhanced CT revealed a nodule smaller than 1 cm which could not be characterized. The 18 F-FDG uptake at follow-up confirmed the malignant nature of pulmonary nodules smaller than 1 cm which were undetectable, misinterpreted, not recognized or undetermined at contrast-enhanced CT. Conclusion In all five oncologic patients, 18 F-FDG was able to metabolically characterize as malignant those nodules smaller than 1 cm, underlining that: 18 F-FDG uptake is not only a function of tumor size but it is strongly related to the tumor biology; functional alterations may precede morphologic abnormalities. In the oncologic population, especially in higher-risk patients, PET can be performed even when the nodules are smaller than 1 cm, because it might give an earlier characterization and, sometimes, could guide in the identification of alterations missed on CT.

Aim: To systematically review the clinical features and outcomes of paediatric patients developing neurological complications associated with a rotavirus infection. Methods: A systematic literature review and meta‐analysis was performed, including articles published from 1984 to 2020. Neurological complications were classified into four groups: encephalitis, cerebellitis, encephalo‐cerebellitis and benign convulsions with mild gastroenteritis (CwG). Results: Out of 68 reports that fulfilled the research criteria, 99 cases of CwG, 39 cases of encephalitis, 18 cases of encephalo‐cerebellitis and five cases of cerebellitis were collected. Ninety‐five patients were from Asia. Median age was 22 (IQR 14–29) months, and the children who developed CwG were significantly younger (19, IQR 12–24 months, p < 0.0001) than the others. Status epilepticus was observed in 23% and 5% of the encephalitis and CwG groups respectively. The most frequently described neuroimaging finding were lesions of the splenium of corpus callosum. Four deaths were reported in the encephalitis group, whereas no fatal events were described in the other groups. Among the surviving children, the encephalo‐cerebellitis group showed the most severe long‐term outcome. All cases of CwG recovered completely. Conclusion: Older age at diagnosis and the development of encephalo‐cerebellitis are associated with a higher risk of long‐term complications. [ABSTRACT FROM AUTHOR]

Introduction: Gallium-68 somatostatin receptor (SMSR) positron emission tomography (PET) is a valuable diagnostic tool for patients with neuroendocrine tumors (NET). To date, a meta-analysis about the diagnostic accuracy of this functional imaging method is lacking. Aim(s): To meta-analyze published data about the diagnostic performance of SMSR PET or PET/CT in patients with NET. Materials and methods: A comprehensive literature search of studies published in PubMed, Scopus and Embase databases through October 2011 and regarding SMSR PET or PET/CT in patients with NET was carried out. Only studies in which SMSR PET or PET/CT were performed in patients with thoracic and/or gastroenteropancreatic (GEP) NET were selected (medullary thyroid tumors and paragangliomas were excluded from the analysis). Pooled sensitivity, pooled specificity and area under the ROC curve were calculated to measure the diagnostic accuracy of SMSR-PET or PET/CT in NET. Results: Seventeen studies comprising 587 patients were included in this meta-analysis. The pooled sensitivity and specificity of SMSR PET or PET/CT in detecting NET were 93% (95% CI, 91-95%) and 91% (95% CI, 82-97%), respectively, on a per patient-based analysis. The area under the ROC curve was 0.96. Conclusion: In patients with suspicious thoracic and/or GEPNET, SMSR PET or PET/CT demonstrated high sensitivity and specificity. These accurate techniques should be considered as first-line diagnostic imaging methods in patients with suspicious NET. [ABSTRACT FROM AUTHOR]

Introduction: Ectopic ACTH syndrome (EAS) occurs in about 5-10% of ACTH-dependent hypercortisolism and, in up to 15% of cases, is related to occult neoplasms. Aim(s): We report one case of EAS highlighting the usefulness of Nuclear Medicine imaging in pre- and intraoperative localization of the ACTH-secreting neoplasm. Materials and methods: A 66-year-old male patient was diagnosed in 2010 with ACTH-dependent hypercortisolism. Pituitary MRI was negative, while a chest-abdomen CT scan described a 7-mm nodule in the upper lobe of the right lung. Bilateral Inferior Petrosal Sinus Sampling (BIPSS) showed no evidence of center-periphery ACTH gradient. An Octreoscan did not reveal any area of pathological hyperuptake. Treatment with ketoconazole and lanreotide was started with clinical benefit. In July 2011, the patient underwent a PET/CT scan with 68Ga-DOTANOC that revealed mild hyperuptake of the lung nodule. Results: In September 2011, the patient underwent radio-guided surgery using a hand-held gamma probe 24 h after i.v. administration of 111In-pentetreotide. The pulmonary nodule was identified, confirmed by the gamma probe and surgically removed. Pathology confirmed a typical bronchial carcinoid with positive ACTH expression. Conclusion: This case underlines how the integration of traditional diagnostic tools with both Nuclear Medicine imaging and intraoperative techniques can guarantee an improvement in the diagnostic and therapeutic management of neuroendocrine neoplasms. [ABSTRACT FROM AUTHOR]