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Coronavirus(CoV) and human metaneumovirus(hMPV) are worldwide causes of lower respiratory tract infection(LRTI) in adults Chest CT is increasingly used in the diagnosis and management of LRTI Our aims were to compare chest CT features for LRTI due to sporadic CoV with hMPV and correlate chest CT findings with clinical outcomes We retrospectively reviewed records of 61 adults with nucleic acid amplification(NAA) assay positive for CoV and 104 adults positive for hMPV over 33 months at 4 community hospitals in the northeast US A thoracic radiologist reviewed all chest CT images Inclusion criteria included:1 symptoms of acute LRTI, 2 chest CT within 7 days of positive NAA assay, 3 no other pulmonary infection/lung disease that might interfere with chest CT interpretation Ground-glass opacities(GGO) were more frequent (p< 05) with hMPV(47/104,45%) than with sporadic CoV(15/61,25%) Multifocal consolidation was more common (p< 05) with hMPV(31/104,30%) than with sporadic CoV(8/61,13%) LRTI without chest CT findings was more common (p< 05) with sporadic CoV (28/61,46%) than with hMPV (16/104,15%) For hMPV, multifocal consolidation was associated(p< 05) with treatment with assisted ventilation(9/30,30%) For hMPV, no other chest CT finding correlated with any studied outcome(new supplementary oxygen at discharge, discharge to skilled facility, hospital re-admission within 30 days) No chest CT finding correlated with any studied outcome for sporadic CoV With hMPV, healthcare providers should be aware that multifocal consolidation on chest CT often portends treatment with invasive/non-invasive ventilatory support

Human metapneumovirus (hMPV) has increasingly been identified as an important, worldwide cause of lower respiratory tract infections (LRTI) in adults. Our goals were to determine the chest CT imaging features of LRTI due to hMPV and to correlate chest CT imaging features with clinical outcomes. We retrospectively reviewed the medical records and chest CT images of 100 adults collected over 33 months at 4 community hospitals in the northeast US. Chest CT images were reviewed by an experienced thoracic radiologist. Study subjects satisfied 4 criteria: 1. acute lower respiratory tract symptoms, 2. positive reverse-transcriptase polymerase chain reaction (RT-PCR) assay of nasopharyngeal swab for hMPV, 3. chest CT within 7 days of positive RT-PCR assay for hMPV, 4. no other pulmonary infection or other pulmonary disease that might interfere with chest CT interpretation. On review, 16/100 had focal lung consolidation, 30/100 had multifocal lung consolidation, 31/100 had bronchial wall thickening, 44/100 had ground glass opacities and 62/100 had tree-in-bud opacities. Multifocal lung consolidation was associated with increased frequency (9/30, 30%) of treatment with invasive or non-invasive ventilatory support (p

Purpose Human metapneumovirus has been increasingly identified as a cause of lower respiratory tract infection in adults worldwide. The CT imaging features of human metapneumovirus in adults have not been characterized. The purpose of this paper is to determine the imaging features of human metapneumovirus and to compare them with features of other viruses. Methods Two clinicians retrospectively reviewed the medical records of 104 adults with lower respiratory tract infection due to human metapneumovirus at four hospitals in the northeast USA over 32 months. CT images were evaluated by two chest radiologists for airspace consolidation, bronchiectasis, bronchial wall thickening, ground-glass opacities, pleural effusion and tree-in-bud opacities and the dominant imaging pattern. Results for human metapneumovirus were compared with results previously reported for other viruses. Results Human metapneumovirus predominantly caused an airway-centric pattern (71-81/104, 68-77%) of infection characterized by bronchial wall thickening, tree-in-bud opacities, peri-bronchial consolidation and/or peri-bronchial ground-glass opacities. The airway-centric pattern has been previously reported with other paramyxoviridae (parainfluenza virus and respiratory syncytial virus). However, human metapneumovirus was significantly more likely (p = 0.03-0.001) to cause bronchopneumonia (46-55%) than parainfluenza virus (17%) or respiratory syncytial virus (21%). Follow-up CT in 41 (39%) patients with hMPV revealed resolution of findings in 38/41 (91%). Conclusion The paramyxoviridae, including human metapneumovirus, are known to have a propensity to infect ciliated respiratory cells and we have demonstrated this leads to a propensity to cause bronchitis, bronchiolitis and bronchopneumonia on CT scans. Of these, human metapneumovirus is most likely to cause bronchopneumonia. Healthcare providers should consider human metapneumovirus as a cause of pneumonia on chest CT.

Coronavirus(CoV) has been associated with lower respiratory tract infection(LRTI) in adults worldwide. The CoV associated with Sudden Acute Respiratory Syndrone and Middle East Respiratory Syndrone typically cause ground-glass opacities(GGO) and/or consolidation on chest CT. Chest CT features of sporadic CoV(subtypes: HKU1, NL63, OC43, 229E) have not been characterizedc. Our aims were to characterize chest CT features of sporadic CoV and compare these findings with those from other viruses. We retrospectively reviewed the records and chest CT images of 61 adults over 32 months at 4 community hospitals in the northeast US. CT images were reviewed by an experienced thoracic radiologist. Study subjects satisfied 4 criteria: 1) symptoms of acute LRTI, 2) positive polymerase chain reaction assay for CoV, 3)CT within 7 days of positive assay for CoV, 4)no other pulmonary infection or other pulmonary disease that might interfere with CT interpretation. We compared the chest CT features of sporadic CoV with those we previously reported for adenovirus, influenza, human metapneumovirus (hMPV), parainfluenza virus (PIV) and respiratory syncytial virus. On review of CoV cases, 11(18%) had bronchial wall thickening, 15(25%) had GGO, 12(20%) had lung consolidation and 13(21%) had tree-in-bud opacities. Twenty-eight(46%) had no chest CT findings related to acute infection. Sporadic CoV was similar to influenza but different from PIV (p

To evaluate the rate of agreement of pulmonary embolism diagnosis in computed tomography (CT) pulmonary angiogram studies and to evaluate the rate of inaccurate interpretations in the community hospital setting.Using the keywords "pulmonary embolism/embolus/emboli," the radiology information system was searched for CT pulmonary angiograms performed over a 3-year period at three U.S. community hospitals. Studies containing probable or definite pulmonary emboli were independently reviewed by four subspecialty thoracic radiologists.Agreement about the presence of pulmonary embolism progressively decreased with decreasing diameter of pulmonary vascular lesions (P 0.0001). There was a sharp fall in observer agreement for pulmonary embolism of subsegmental lesions (P 0.0001). The frequency of agreement decreased with decreasing quality of the imaging examination (P 0.0001). Community radiologists were prone to false-positive pulmonary embolism diagnosis of subsegmental and/or small pulmonary arterial defects. The probability of a false-positive diagnosis and indeterminate examinations progressively increased with: (1) more peripheral location of the lesion, (2) decreased size (short-axis diameter) of the lesion, and (3) diminishing quality of the CT examination. Forty-eight of 177 (27%) of subsegmental vascular defects identified by community radiologists were deemed indeterminate, and 27 of 177 (15%) of subsegmental vascular defects were judged to be false positive for pulmonary embolism by the consensus diagnosis. Fifty-four of 274 (20%) vascular defects with short axis less than 6 mm were indeterminate for pulmonary embolism, and 37 of 274 (14%) of vascular defects with short axis less than 6 mm were false positive for pulmonary embolism. Eleven of 13 (85%) of vascular lesions identified as pulmonary emboli on the lowest-quality CT examinations were false positive or indeterminate for pulmonary embolism. False-positive examinations were most often due to respiratory motion artifact (19/38, 50%).There is relatively poor interobserver agreement for subsegmental and/or small pulmonary artery defects, especially in CT pulmonary angiograms degraded by technical artifacts. These factors can lead to an increased frequency of inaccurate interpretation or indeterminate diagnosis of subsegmental and/or small defects. Caution is indicated in interpreting the significance of small vascular defects in CT pulmonary angiograms.