Air trapping in sarcoidosis on computed tomography: Correlation with lung function

AIMS: To document the presence and extent of air trapping on high resolution computed tomography (HRCT) in patients with pulmonary sarcoidosis and correlate HRCT features with pulmonary function tests. METHODS: Twenty-one patients with pulmonary sarcoidosis underwent HRCT and pulmonary function assessment at presentation. Inspiratory and expiratory HRCT were assessed for the presence and extent of air trapping, ground-glass opacification, nodularity, septal thickening, bronchiectasis and parenchymal distortion. HRCT features were correlated with pulmonary function tests. RESULTS: Air trapping on expiratory HRCT was present in 20/21 (95%) patients. The extent of air trapping correlated with percentage predicted residual volume (RV)/total lung capacity (TLC) (r = 0.499; P < 0.05) and percentage predicted maximal mid-expiratory flow rate between 25 and 75% of the vital capacity (r = -0.54; P < 0,05). Ground-glass opacification was present in four of 21 (19%), nodularity in 18/21 (86%), septal thickening in 18/21 (86%), traction bronchiectasis in 14/21 (67%) and distortion in 12/21 (57%) of patients; there were no significant relationships between these CT features and pulmonary function results. CONCLUSION: Air trapping is a common feature in sarcoidosis and correlates with evidence of small airways disease on pulmonary function testing. (C) 2000 The Royal College of Radiologists

Prevalence of Thrombotic Complications in ICU-Treated Patients With Coronavirus Disease 2019 Detected With Systematic CT Scanning

Copyright © by 2021 by the Society of Critical Care Medicine and Wolters Kluwer Health, Inc. All Rights Reserved.Objective: Severe Coronavirus disease 2019 (COVID-19) is associated with an extensive pneumonitis, and frequent coagulopathy. We sought the true incidence of thrombotic complications in critically ill patients with severe COVID-19 on the intensive care unit (ICU), with or without extracorporeal membrane oxygenation (ECMO). Design: We undertook a single-centre, retrospective analysis of 72 critically ill patients with COVID-19 associated acute respiratory distress syndrome admitted to ICU. CT angiography of the thorax, abdomen and pelvis were performed on admission as per routine institution protocols, with further imaging as clinically indicated. The prevalence of thrombotic complications and the relationship with coagulation parameters, other biomarkers and survival were evaluated.. Setting: COVID-19 ICUs at a specialist cardiorespiratory centre. Patients: Seventy two consecutive patients with COVID-19 admitted to ICU during the study period (19/03/2020-23/06/2020). Interventions: None. Measurements and Main Results: All but one patient received thromboprophylaxis or therapeutic anticoagulation. Amongst 72 patients (M:F=74%; mean age: 52+10; 35 on ECMO), there were 54 thrombotic complications in 42 patients (58%), comprising 34 pulmonary arterial (47%), 15 peripheral venous (21%), and 5 (7%) systemic arterial thromboses / end-organ embolic complications. In those with pulmonary arterial thromboses, 93% were identified incidentally on first screening CT with only 7% suspected clinically. Biomarkers of coagulation (eg. D-dimer, Fibrinogen level, APTT) or inflammation (white cell count, CRP), did not discriminate between patients with or without thrombotic complications. Fifty-one patients (76%) survived to discharge; 17 (24%) patients died. Mortality was significantly greater in patients with detectable thrombus (33% vs. 10%, p=0.022). Conclusions: There is a high incidence of thrombotic complications, mainly pulmonary, amongst COVID-19 patients admitted to ICU, despite anticoagulation. Detection of thrombus was usually incidental, not predicted by coagulation or inflammatory biomarkers, and associated with increased risk of death. Systematic CT imaging at admission should be considered in all COVID-19 patients requiring ICU.Peer reviewe

Dual-energy computed tomographic pulmonary angiography accurately estimates lobar perfusion before lung volume reduction for severe emphysema.

PURPOSE: To assess if dual-energy computed tomographic pulmonary angiography (DECTPA) derived lobar iodine quantification can provide an accurate estimate of lobar perfusion in patients with severe emphysema, and offer an adjunct to single-photon emission CT perfusion scintigraphy (SPECT-PS) in assessing suitability for lung volume reduction (LVR). MATERIALS AND METHODS: Patients with severe emphysema (forced expiratory volume in 1 s <49% predicted) undergoing evaluation for LVR between May 2018 and April 2020 imaged with both SPECT-PS and DECTPA were included in this retrospective study. DECTPA perfused blood volume maps were automatically segmented and lobar iodine mass was estimated and compared with lobar technetium (Tc99m) distribution acquired with SPECT-PS. Pearson correlation and Bland-Altman analysis were used for intermodality comparison between DECTPA and SPECT-PS. Univariate and adjusted multivariate linear regression were modelled to ascertain the effect sizes of possible confounders of disease severity, sex, age, and body mass index on the relationship between lobar iodine and Tc99m values. Effective radiation dose and adverse reactions were recorded. RESULTS: In all, 123 patients (64.5±8.8 y, 71 men; mean predicted forced expiratory volume in 1 s 32.1 ±12.7%,) were eligible for inclusion. There was a linear relationship between lobar perfusion values acquired using DECTPA and SPECT-PS with statistical significance (P<0.001). Lobar relative perfusion values acquired using DECTPA and SPECT-PS had a consistent relationship both by linear regression and Bland-Altman analysis (mean bias, -0.01, mean r2 0.64; P<0.0001). Individual lobar comparisons demonstrated moderate correlation (r=0.79, 0.78, 0.84, 0.78, 0.8 for the right upper, middle, lower, left upper, and lower lobes, respectively, P<0.0001). The relationship between lobar iodine and Tc99m values was not significantly altered after controlling for confounders including symptom and disease severity, age, sex, and body mass index. CONCLUSIONS: DECTPA provides an accurate estimation of lobar perfusion, showing good agreement with SPECT-PS and could potentially streamline preoperative assessment for LVR

Dual-energy CT pulmonary angiography (DECTPA) quantifies vasculopathy in severe COVID-19 pneumonia

Background The role of dual energy computed tomographic pulmonary angiography (DECTPA) in revealing vasculopathy in coronavirus disease 2019 (COVID-19) has not been fully explored. Purpose To evaluate the relationship between DECTPA and disease duration, right ventricular dysfunction (RVD), lung compliance, D-dimer and obstruction index in COVID-19 pneumonia. Materials and Methods This institutional review board approved this retrospective study, and waived the informed consent requirement. Between March-May 2020, 27 consecutive ventilated patients with severe COVID-19 pneumonia underwent DECTPA to diagnose pulmonary thrombus (PT); 11 underwent surveillance DECTPA 14 ±11.6 days later. Qualitative and quantitative analysis of perfused blood volume (PBV) maps recorded: i) perfusion defect ‘pattern’ (wedge-shaped, mottled or amorphous), ii) presence of PT and CT obstruction index (CTOI) and iii) PBV relative to pulmonary artery enhancement (PBV/PAenh); PBV/PAenh was also compared with seven healthy volunteers and correlated with D-Dimer and CTOI. Results Amorphous (n=21), mottled (n=4), and wedge-shaped (n=2) perfusion defects were observed (M=20; mean age=56 ±8.7 years). Mean extent of perfusion defects=36.1%±17.2. Acute PT was present in 11/27(40.7%) patients. Only wedge-shaped defects corresponded with PT (2/27, 7.4%). Mean CTOI was 2.6±5.4 out of 40. PBV/PAenh (18.2 ±4.2%) was lower than in healthy volunteers (27 ±13.9%, p = 0.002). PBV/PAenh correlated with disease duration (β = 0.13, p = 0.04), and inversely correlated with RVD (β = -7.2, p = 0.001), persisting after controlling for confounders. There were no linkages between PBV/PAenh and D-dimer or CTOI. Conclusion Perfusion defects and decreased PBV/PAenh are prevalent in severe COVID-19 pneumonia. PBV/PAenh correlates with disease duration and inversely correlates with RVD. PBV/PAenh may be an important marker of vasculopathy in severe COVID-19 pneumonia even in the absence of arterial thrombus. Summary Significantly decreased (qualitative and quantitative) lung enhancement on dual-energy CT pulmonary angiography is an early feature of severe COVID-19 pneumonia and is associated with right ventricular dysfunction

Pulmonary angiopathy in severe COVID-19: physiologic, imaging and hematologic observations

Rationale: Clinical and epidemiologic data in coronavirus disease 2019 (Covid-19) have accrued rapidly since the outbreak but few address the underlying pathophysiology. Objectives: To ascertain the physiologic, hematologic and imaging basis of lung injury in severe Covid-19 pneumonia. Methods: Clinical, physiologic and laboratory data were collated. Radiologic (computed tomography pulmonary angiography [CTPA, n=39] and dual-energy CT [DECT, n=20]) studies were evaluated: observers quantified CT patterns (including the extent of abnormal lung and the presence/extent of dilated peripheral vessels) and perfusion defects on DECT. Coagulation status was assessed using thromboelastography (TEG). Measurements and Results: In 39 consecutive patients (M:F 32:7; mean age, 53±10 years [range 29-79 years]; black and ethnic minority, n=25 [64%]), there was a significant vascular perfusion abnormality and increased physiologic dead-space (dynamic compliance, 33.7±14.7 mls/cmH2O; Murray Lung Injury Score, 3.14±0.53; mean ventilatory ratios, 2.6±0.8) with evidence of hypercoagulability and fibrinolytic ‘shutdown’. The mean CT extent (±SD) of normally-aerated lung, ground-glass opacification and dense parenchymal opacification were 23.5±16.7%, 36.3±24.7% and 42.7±27.1%, respectively. Dilated peripheral vessels were present in 21/33 (63.6%) patients with at least two assessable lobes (including 10/21 [47.6%] with no evidence of acute pulmonary emboli). Perfusion defects on DECT (assessable in 18/20 [90%]), were present in all patients (wedge-shaped, n=3; mottled, n= 9; mixed pattern, n=6). Conclusions: Physiologic, hematologic and imaging data show not only the presence of a hypercoagulable phenotype in severe Covid-19 pneumonia but also markedly impaired pulmonary perfusion likely caused by pulmonary angiopathy and thrombosis