Objective: The halo sign consists of an area of ground-glass opacity surrounding pulmonary lesions on chest CT scans. We compared immunocompetent and immunosuppressed patients in terms of halo sign features and sought to identify those of greatest diagnostic value. Methods: This was a retrospective study of CT scans performed at any of seven centers between January of 2011 and May of 2015. Patients were classified according to their immune status. Two thoracic radiologists reviewed the scans in order to determine the number of lesions, as well as their distribution, size, and contour, together with halo thickness and any other associated findings. Results: Of the 85 patients evaluated, 53 were immunocompetent and 32 were immunosuppressed. Of the 53 immunocompetent patients, 34 (64%) were diagnosed with primary neoplasm. Of the 32 immunosuppressed patients, 25 (78%) were diagnosed with aspergillosis. Multiple and randomly distributed lesions were more common in the immunosuppressed patients than in the immunocompetent patients (p < 0.001 for both). Halo thickness was found to be greater in the immunosuppressed patients (p < 0.05). Conclusions: Etiologies of the halo sign differ markedly between immunocompetent and immunosuppressed patients. Although thicker halos are more likely to occur in patients with infectious diseases, the number and distribution of lesions should also be taken into account when evaluating patients presenting with the halo sign.

Keywords: Tomography, X-ray computed; Aspergillosis; Lung neoplasms.

Objective: To identify the indications for physiotherapy and to evaluate physiotherapy practices in patients with COVID-19 admitted to the ICU (on mechanical ventilation) or to the ward (spontaneously breathing). Methods: An online, 50-item survey was completed by physiotherapists who had been treating hospitalized patients with COVID-19 in Brazil. Results: Of the 644 physiotherapists who initiated the survey, 488 (76%) completed it. The main reasons for indications for physiotherapy in both settings reported as "very frequently" and "frequently" both in the ICU and the ward by most respondents were oxygenation improvement (> 95%) and prevention of general complications (> 83%). Physical deconditioning was considered an infrequent indication. When compared with mobilization strategies, the use of respiratory interventions showed great variability in both work settings, and techniques considered effective were underutilized. The most frequently used respiratory techniques in the ICU were positioning (86%), alveolar recruitment (73%), and hard/brief expiratory rib cage compression (46%), whereas those in the ward were active prone positioning (90%), breathing exercises (88%), and directed/assisted cough (75%). The mobilization interventions reported by more than 75% of the respondents were sitting on the edge of the bed, active and resistive range of motion exercises, standing, ambulation, and stepping in place. Conclusions: The least common reason for indications for physiotherapy was avoidance of deconditioning, whereas oxygenation improvement was the most frequent one. Great variability in respiratory interventions was observed when compared with mobilization therapies, and there is a clear need to standardize respiratory physiotherapy treatment for hospitalized patients with COVID-19.

Keywords: COVID-19; Physical therapy modalities; Hospitalization; Critical illness; Surveys and questionnaires.

Objective: To determine the incidence of the reversed halo sign (RHS) in patients with pulmonary infarction (PI) due to acute pulmonary embolism (PE), detected by computed tomography angiography (CTA) of the pulmonary arteries, and to describe the main morphological features of the RHS. Methods: We evaluated 993 CTA scans, stratified by the risk of PE, performed between January of 2010 and December of 2014. Although PE was detected in 164 scans (16.5%), three of those scans were excluded because of respiratory motion artifacts. Of the remaining 161 scans, 75 (46.6%) showed lesions consistent with PI, totaling 86 lesions. Among those lesions, the RHS was seen in 33 (38.4%, in 29 patients). Results: Among the 29 patients with scans showing lesions characteristic of PI with the RHS, 25 (86.2%) had a single lesion and 4 (13.8%) had two, totaling 33 lesions. In all cases, the RHS was in a subpleural location. To standardize the analysis, all images were interpreted in the axial plane. Among those 33 lesions, the RHS was in the right lower lobe in 17 (51.5%), in the left lower lobe in 10 (30.3%), in the lingula in 5 (15.2%), and in the right upper lobe in 1 (3.0%). Among those same 33 lesions, areas of low attenuation were seen in 29 (87.9%). The RHS was oval in 24 (72.7%) of the cases and round in 9 (27.3%). Pleural effusion was seen in 21 (72.4%) of the 29 patients with PI and the RHS. Conclusions: A diagnosis of PE should be considered when there are findings such as those described here, even in patients with nonspecific clinical symptoms.

Keywords: Pulmonary embolism; Pulmonary infarction; Computed tomography angiography.