False-negative RT-PCR for COVID-19 and a diagnostic risk score: a retrospective cohort study among patients admitted to hospital.

Objective: To describe the characteristics and outcomes of patients with a clinical diagnosis of COVID-19 and false-negative SARS-CoV-2 reverse transcription-PCR (RT-PCR), and develop and internally validate a diagnostic risk score to predict risk of COVID-19 (including RT-PCR-negative COVID-19) among medical admissions.

Design: Retrospective cohort study.

Setting: Two hospitals within an acute NHS Trust in London, UK.

Immunotherapy-related adverse effects on F-FDG PET/CT imaging.

F-Fluorodeoxyglucose positron emission tomography/CT imaging plays a key role in oncological imaging including in staging, radiotherapy planning, treatment response and recurrence assessment. Immunotherapies represent a major advance in cancer therapy for a number of tumours with resulting survival benefit. However, a wide range of immune related adverse events (irAEs), some of which can be apparent on imaging, have been reported.

Interobserver agreement of the visual Herder scale for the assessment of solitary pulmonary nodules on 18F Fluorodeoxyglucose PET/computed tomography.

Background: British Thoracic Society guidelines recommend 18F Fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) for solitary pulmonary nodule (SPN) follow-up in high-risk individuals or if the CT Brock score is >10%. Nodule tracer uptake is assessed visually in comparison to the surrounding lung tissue and mediastinal blood pool (Herder score). This score is used to calculate the risk of malignancy and guide patient management.

FDG-PET Imaging in Cervical Cancer.

FDG-PET/CT has an established role in the initial staging of locally advanced cervical cancers, particularly in evaluation of nodal disease and distant metastases. It is common practice to perform FDG-PET/CT 3 months postcompletion of chemoradiotherapy as it can predict outcome and be used to tailor management, including adjuvant therapy and follow-up. It is also routinely used prior to pelvic exenterative surgery to ensure there is no disease outside the pelvis.

Osteoporosis Circumscripta on 68Ga-DOTATATE PET CT.

Incidental findings on PET CT studies are common. The distribution of Ga-DOTATATE is dependent on cell surface expression of somatostatin receptors, which may be pathologic or physiologic. Osteoporosis circumscripta is the early lytic phase of Paget disease associated with well-defined osteopenia, most commonly seen within the skull on imaging.

The Racoon Eye Sign in the Investigation of Dementia Using 18F-Florbetaben.

Differentiating Alzheimer disease (AD) from other forms of cognitive impairment and from normal aging can be challenging. As a consequence, the diagnosis of AD can be delayed, often occurring too late for meaningful intervention. The role of β-amyloid plaques in the pathogenesis of AD provides a target for highly sensitive and specific image quantification of amyloid plaque burden using β-amyloid PET (F-florbetaben).