Strategies to safely rule out pulmonary embolism in COVID-19 outpatients: a multicenter retrospective study.

OBJECTIVES: The objective was to define a safe strategy to exclude pulmonary embolism (PE) in COVID-19 outpatients, without performing CT pulmonary angiogram (CTPA). METHODS: COVID-19 outpatients from 15 university hospitals who underwent a CTPA were retrospectively evaluated. D-Dimers, variables of the revised Geneva and Wells scores, as well as laboratory findings and clinical characteristics related to COVID-19 pneumonia, were collected. CTPA reports were reviewed for the presence of PE and the extent of COVID-19 disease. PE rule-out strategies were based solely on D-Dimer tests using different thresholds, the revised Geneva and Wells scores, and a COVID-19 PE prediction model built on our dataset were compared. The area under the receiver operating characteristics curve (AUC), failure rate, and efficiency were calculated. RESULTS: In total, 1369 patients were included of whom 124 were PE positive (9.1%). Failure rate and efficiency of D-Dimer > 500 µg/l were 0.9% (95%CI, 0.2-4.8%) and 10.1% (8.5-11.9%), respectively, increasing to 1.0% (0.2-5.3%) and 16.4% (14.4-18.7%), respectively, for an age-adjusted D-Dimer level. D-dimer > 1000 µg/l led to an unacceptable failure rate to 8.1% (4.4-14.5%). The best performances of the revised Geneva and Wells scores were obtained using the age-adjusted D-Dimer level. They had the same failure rate of 1.0% (0.2-5.3%) for efficiency of 16.8% (14.7-19.1%), and 16.9% (14.8-19.2%) respectively. The developed COVID-19 PE prediction model had an AUC of 0.609 (0.594-0.623) with an efficiency of 20.5% (18.4-22.8%) when its failure was set to 0.8%. CONCLUSIONS: The strategy to safely exclude PE in COVID-19 outpatients should not differ from that used in non-COVID-19 patients. The added value of the COVID-19 PE prediction model is minor. KEY POINTS: • D-dimer level remains the most important predictor of pulmonary embolism in COVID-19 patients. • The AUCs of the revised Geneva and Wells scores using an age-adjusted D-dimer threshold were 0.587 (95%CI, 0.572 to 0.603) and 0.588 (95%CI, 0.572 to 0.603). • The AUC of COVID-19-specific strategy to rule out pulmonary embolism ranged from 0.513 (95%CI: 0.503 to 0.522) to 0.609 (95%CI: 0.594 to 0.623).

Idiopathic inflammatory myopathies: CT characteristics of interstitial lung disease and their association(s) with myositis-specific autoantibodies.

OBJECTIVES: Interstitial lung disease (ILD), one of the most common extramuscular manifestations of idiopathic inflammatory myopathies (IIMs), carries a poor prognosis. Myositis-specific autoantibody (MSA)-positivity is a key finding for IIM diagnosis. We aimed to identify IIM-associated lung patterns, evaluate potential CT-ILD finding-MSA relationships, and assess intra- and interobserver reproducibility in a large IIM population. METHODS: All consecutive IIM patients (2003-2019) were included. Two chest radiologists retrospectively assessed all chest CT scans. Multiple correspondence and hierarchical cluster analyses of CT findings identified and characterized ILD-patient subgroups. Classification and regression-tree analyses highlighted CT-scan variables predicting three patterns. Three independent radiologists read CT scans twice to assign patients according to CT-ILD-pattern clusters. RESULTS: Among 257 IIM patients, 94 (36.6%) had ILDs; 87 (93%) of them were MSA-positive. ILD-IIM distribution was 54 (57%) ASyS, 21 (22%) DM, 15 (16%) IMNM, and 4 (4%) IBM. Cluster analysis identified three ILD-patient subgroups. Consolidation characterized cluster 1, with significantly (p < 0.05) more frequent anti-MDA5-autoantibody-positivity. Significantly more cluster-2 patients had a reticular pattern, without cysts and with few consolidations. All cluster-3 patients had cysts and anti-PL12 autoantibodies. Clusters 2 and 3 included significantly more ASyS patients. Intraobserver concordances to classify patients into those three clusters were good-to-excellent (Cohen κ 0.64-0.81), with good interobserver reliability (Fleiss's κ 0.56). CONCLUSION: Despite the observed IIM heterogeneity, CT-scan criteria enabled ILD assignment to the three clusters, which were associated with MSAs. Radiologist identification of those clusters could facilitate diagnostic screening and therapeutics. Interstitial lung disease in patients with idiopathic inflammatory myopathy could be classified into three clusters according to CT-scan criteria, and these clusters were significantly associated with myositis-specific autoantibodies. KEY POINTS: • Cluster analysis discerned three homogeneous groups of interstitial lung disease (ILD) for which cysts, consolidations, and reticular pattern were discriminatory, and associated with myositis-specific autoantibodies. • Like muscle- and extramuscular-specific phenotypes, myositis-specific autoantibodies are also associated with specific ILD patterns in patients with idiopathic inflammatory myopathies.

Residual ground glass opacities three months after Covid-19 pneumonia correlate to alteration of respiratory function: The post Covid M3 study.

INTRODUCTION: Lung function in survivors of SARS-Co-V2 pneumonia is poorly known, but concern over the possibility of sequelae exists. METHODS: Retrospective study on survivors with confirmed infection and pneumonia on chest-CT. Correlations between PFT and residual radiologic anomalies at three months taking into account initial clinical and radiological severity and steroid use during acute phase. RESULTS: 137 patients (69 men, median age 59 (Q1 50; Q3 68), BMI 27.5 kg/m2 (25.1; 31.7)) were assessed. Only 32.9% had normal PFT, 75 had altered DLCO. Median (Q1; Q3) values were: VC 79 (66; 92) % pred, FEV1 81 (68; 89), TLC 78 (67; 85), DLCO 60 (44; 72), and KCO 89 (77; 105). Ground glass opacities (GGO) were present in 103 patients (75%), reticulations in 42 (30%), and fibrosis in 18 (13%). There were significantly lower FEV1 (p = 0.0089), FVC (p = 0.0010), TLC (p < 0.0001) and DLCO (p < 0.0001) for patients with GGO, lower TLC (p = 0.0913) and DLCO (p = 0.0181) between patients with reticulations and lower FVC (p = 0.0618), TLC (p = 0.0742) DLCO (p = 0.002) and KCO (p = 0.0114) between patients with fibrosis. Patients with initial ≥50% lung involvement had significantly lower FEV1 (p = 0.0019), FVC (p = 0.0033), TLC (p = 0.0028) and DLCO (p = 0.0003) compared to patients with ≤10%. There was no difference in PFT and residual CT lesions between patients who received steroids and those who did not. CONCLUSION: The majority of patients have altered PFT at three months, even in patients with mild initial disease, with significantly lower function in patients with residual CT lesions. Steroids do not seem to modify functional and radiological recovery. Long-term follow-up is needed.

Diagnostic performance of chest computed tomography during the epidemic wave of COVID-19 varied as a function of time since the beginning of the confinement in France.

OBJECTIVE: To evaluate the diagnostic performance of the initial chest CT to diagnose COVID-19 related pneumonia in a French population of patients with respiratory symptoms according to the time from the onset of country-wide confinement to better understand what could be the role of the chest CT in the different phases of the epidemic. MATERIAL AND METHOD: Initial chest CT of 1064 patients with respiratory symptoms suspect of COVID-19 referred between March 18th, and May 12th 2020, were read according to a standardized procedure. The results of chest CTs were compared to the results of the RT-PCR. RESULTS: 546 (51%) patients were found to be positive for SARS-CoV2 at RT-PCR. The highest rate of positive RT-PCR was during the second week of confinement reaching 71.9%. After six weeks of confinement, the positive RT-PCR rate dropped significantly to 10.5% (p<0.001) and even 2.2% during the two last weeks. Overall, CT revealed patterns suggestive of COVID-19 in 603 patients (57%), whereas an alternative diagnosis was found in 246 patients (23%). CT was considered normal in 215 patients (20%) and inconclusive in 1 patient. The overall sensitivity of CT was 88%, specificity 76%, PPV 79%, and NPV 85%. At week-2, the same figures were 89%, 69%, 88% and 71% respectively and 60%, 84%, 30% and 95% respectively at week-6. At the end of confinement when the rate of positive PCR became extremely low the sensitivity, specificity, PPV and NPV of CT were 50%, 82%, 6% and 99% respectively. CONCLUSION: At the peak of the epidemic, chest CT had sufficiently high sensitivity and PPV to serve as a first-line positive diagnostic tool but at the end of the epidemic wave CT is more useful to exclude COVID-19 pneumonia.

Prevalence of pulmonary embolism in emergency department patients with isolated syncope: a prospective cohort study.

BACKGROUNDS: Paramount to guide the diagnostic strategy, the prevalence of pulmonary embolism in patients with syncope and no other symptoms is uncertain. We aimed to assess the pulmonary embolism prevalence in patients that present to the emergency department (ED) with syncope and no chest pain nor dyspnea. METHODS: Multicenter prospective cohort study in seven EDs in France. Adult patients who presented to the ED with syncope (transient loss of consciousness) were included. Patients with chest pain or dyspnea were excluded. Included patients underwent formal work-up for pulmonary embolism, including D-dimer testing and further imaging if positive. Cases of pulmonary embolism were adjudicated by two independent expert radiologists with the review of imaging studies. Secondary objectives included the pulmonary embolism prevalence in the subgroup of patients with cancer, in patients with negative Pulmonary Embolism Rule Out criteria (PERC) score, and according to the clinical probability assessed either by Wells or revised Geneva score. RESULTS: We analyzed 411 patients, in whom 128 (31%) underwent a computed tomographic pulmonary angiogram and 9 (2%) a ventilation-perfusion scan. A pulmonary embolism was confirmed in nine patients (prevalence of 2.2%, 95% confidence interval, 1.1-4.3%), including one subsegmental pulmonary embolism. This prevalence was of 18% (3-52%) in patients with cancer and 0.7% (0.1-4%) in PERC negative patients. CONCLUSION: In our sample of patients with isolated syncope, the prevalence of pulmonary embolism was 2.2%. This value is not sufficiently low to negate the requirement for a formal work up in the ED, even in the absence of chest pain or dyspnea. However, the large confidence interval precludes any strong conclusion.

Low-dose paediatric cardiac and thoracic computed tomography with prospective triggering: Is it possible at any heart rate?

OBJECTIVE: To demonstrate that the use of step-and-shoot (SAS) mode in paediatric cardiac CT angiography (CCTA) is possible at heart rates (HR) greater than 65 bpm, allowing low-dose acquisition with single-source 64-slices CT. METHODS: We retrospectively included 125 paediatric patients (0-6 years). CCTA was performed with SAS at diastolic phase in 31 patients (group D, HR < 65 bpm), at systolic phase in 45 patients (group S, HR ≥ 65 bpm) and with non-gated mode in 49 patients (group NG). Effective dose (ED) and image quality using a 3-grade scoring scale (1, excellent; 2, moderate; 3, insufficient) of group S were compared with group D for coronary examinations and group NG for entire thorax vascular anatomy. RESULTS: For coronary indications, median ED was 0.6 mSv in group D versus 0.9 mSv in group S (p < 0.01). For whole thorax indications, median ED was 2.7 mSv in group NG versus 1.1 mSv in group S (p < 0.001). The mean image quality score was (1.4 ±â€¯0.6) points in group D, (1.4 ±â€¯0.7) in group S for coronary indications (p = 0.9), (1.3 ±â€¯0.6) in group S for whole thorax indications and (2.0 ±â€¯0.0) in group NG (p < 0.001). CONCLUSION: SAS mode is feasible in children with HR greater than 65 bpm allowing low-dose CCTA. It provided comparable image quality in systole, compared to diastole. SAS at the systolic phase provided better image quality with less radiation dose compared to non-gated scans for whole thorax examinations.