FDG PET/CT is accurate and complementary to BMB for detecting bone marrow involvement in patients with newly diagnosed DLBCL. A negative FDG PET/CT scan cannot rule out the presence of bone marrow involvement, but positive FDG PET/CT findings obviate the need for BMB for the detection of bone marrow involvement in these patients.

BACKGROUND: Chest CT may be used for the diagnosis of coronavirus disease 2019 (COVID-19), but clear scientific evidence is lacking. Therefore, we systematically reviewed and metaanalyzed the chest CT imaging signature of COVID-19. RESEARCH QUESTION: What is the chest CT imaging signature of COVID-19 infection? STUDY DESIGN AND METHODS: A systematic literature search was performed for original studies on chest CT imaging findings in patients with COVID-19. Methodologic quality of studies was evaluated. Pooled prevalence of chest CT imaging findings were calculated with the use of a random effects model in case of between-study heterogeneity (predefined as I 2 $50); otherwise, a fixed effects model was used. RESULTS: Twenty-eight studies were included. The median number of patients with COVID-19 per study was 124 (range, 50-476), comprising a total of 3,466 patients. Median prevalence of symptomatic patients was 99% (range, >76.3%-100%). Twenty-seven of the studies (96%) had a retrospective design. Methodologic quality concerns were present with either risk of or actual referral bias (13 studies), patient spectrum bias (eight studies), disease progression bias (26 studies), observer variability bias (27 studies), and test review bias (14 studies). Pooled prevalence was 10.6% for normal chest CT imaging findings. Pooled prevalences were 90.0% for posterior predilection, 81.0% for ground-glass opacity, 75.8% for bilateral abnormalities, 73.1% for left lower lobe involvement, 72.9% for vascular thickening, and 72.2% for right lower lobe involvement. Pooled prevalences were 5.2% for pleural effusion, 5.1% for lymphadenopathy, 4.1% for airway secretions/tree-in-bud sign, 3.6% for central lesion distribution, 2.7% for pericardial effusion, and 0.7% for cavitation/ cystic changes. Pooled prevalences of other CT imaging findings ranged between 10.5% and 63.2%.

er patients, healthcare workers, and visitors, which in turn can infect many other people in the hospital. Hospitals need to ensure that all infected patients are placed in strict isolation to prevent an uncontrollable outbreak of COVID-19. The Centers for Disease Control and Prevention recommend rapid safe triage and isolation of patients suspected to have SARS-CoV-2 or other respiratory infection who come to the hospital [10]. At present, real-time reverse transcriptase-polymerasechain reaction (RT-PCR) assay of nasal and pharyngeal swab specimens is considered the reference standard to detect SARS- . However, given the incubation period of the infection (estimated as 2-14 days), an initial negative RT-PCR result does not rule out infection with SARS-CoV-2 [16]. Furthermore, false-negative results may be due to sampling error or laboratory error [17,18]. Therefore, in patients with a negative RT-PCR test result but persistent clinical

Although the methodological quality of studies that were included in this systematic review and meta-analysis was moderate, the current evidence suggests that FDG-PET/CT may be an appropriate method to replace BMB in newly diagnosed Hodgkin lymphoma.

Whole-body SUVmax , whole-body MTV, and whole-body TLG do not provide any prognostic information in DLBCL beyond that which can already be obtained by the NCCN-IPI. Therefore, the NCCN-IPI remains the most important prognostic tool in this disease.