Semi-Quantitative Scoring of Late Gadolinium Enhancement of the Left Ventricle in Patients with Ischemic Cardiomyopathy: Improving Interobserver Reliability and Agreement Using Consensus Guidance from the Asian Society of Cardiovascular Imaging-Practical Tutorial (ASCI-PT) 2020

Objective@#This study aimed to evaluate the effect of implementing the consensus statement from the Asian Society of Cardiovascular Imaging-Practical Tutorial 2020 (ASCI-PT 2020) on the reliability of cardiac MR with late gadolinium enhancement (CMR-LGE) myocardial viability scoring between observers in the context of ischemic cardiomyopathy. @*Materials and Methods@#A total of 17 cardiovascular imaging experts from five different countries evaluated CMR obtained in 26 patients (male:female, 23:3; median age [interquartile range], 55.5 years [50–61.8]) with ischemic cardiomyopathy. For LGE scoring, based on the 17 segments, the extent of LGE in each segment was graded using a five-point scoring system ranging from 0 to 4 before and after exposure according to the consensus statement. All scoring was performed via webbased review. Scores for slices, vascular territories, and total scores were obtained as the sum of the relevant segmental scores. Interobserver reliability for segment scores was assessed using Fleiss’ kappa, while the intraclass correlation coefficient (ICC) was used for slice score, vascular territory score, and total score. Inter-observer agreement was assessed using the limits of agreement from the mean (LoA). @*Results@#Interobserver reliability (Fleiss’ kappa) in each segment ranged 0.242–0.662 before the consensus and increased to 0.301–0.774 after the consensus. The interobserver reliability (ICC) for each slice, each vascular territory, and total score increased after the consensus (slice, 0.728–0.805 and 0.849–0.884; vascular territory, 0.756–0.902 and 0.852–0.941; total score, 0.847 and 0.913, before and after implementing the consensus statement, respectively. Interobserver agreement in scoring also improved with the implementation of the consensus for all slices, vascular territories, and total score. The LoA for the total score narrowed from ± 10.36 points to ± 7.12 points. @*Conclusion@#The interobserver reliability and agreement for CMR-LGE scoring for ischemic cardiomyopathy improved when following guidance from the ASCI-PT 2020 consensus statement.

CT Imaging Findings in Non-Atherosclerotic Coronary Artery Disease

Acute coronary syndrome (ACS) is mainly caused by atherosclerotic coronary artery disease (CAD); however, it can also occur in patients with non-atherosclerotic CAD. Conventional coronary angiography only shows the lumen of arteries, indicating the presence of stenosis or dilatation. Thus, it has limited value in evaluating the coronary artery wall and offers low specificity for diagnosing CAD. Coronary CT angiography provides additional information, including the depiction of the concerned vessel and the aorta, as well as the pulmonary artery, which permits the diagnosis of non-atherosclerotic CAD and the differentiation of various causes of the disease. In this review, we present the pathophysiology and CT imaging features of non-atherosclerotic CAD.

Pictorial Essay: Understanding of Persistent Left Superior Vena Cava and Its Differential Diagnosis

Persistent left superior vena cava (PLSVC) is a rare congenital, thoracic, and vascular anomaly. Although PLSVCs generally do not have a hemodynamic effect, several types of PLSVC and some cardiac anomalies may manifest with clinical symptoms. The presence of PLSVC can render catheterization via left subclavian access difficult when placing a pacemaker or central venous catheter. As such, recognizing a PLSVC that is typically incidentally discovered can prevent complications such as vascular injury. Differentiating vessels found in a similar location as PLSVC is necessary when performing thoracic vascular procedures. This pictorial essay explains the multi-detector CT findings of a PLSVC, and provides a summary of other blood vessels that require differentiation during thoracic vascular procedures.

Incidentally Detected Pericardial Defect in a Patient with Pneumothorax as Confirmed on Video-Assisted Thoracoscopic Surgery

Congenital defects of the pericardium, which are generally asymptomatic, are rare disorders characterized by complete or partial absence of the pericardium. Here, we report a rare case of a 19-year-old male who was incidentally diagnosed with congenital absence of the left pericardium during examination for symptoms of pneumothorax. Chest radiography and CT revealed a collapsed left lung without any evidence of trauma, no unusual findings of free air spaces along the right side of the ascending aorta, heart shifted toward the left side of the thorax, and a shallow chest. Subsequent thoracoscopy confirmed the absence of the left pericardium and displacement of the heart toward the left thoracic cavity. We further discuss the correlation between radiologic images and surgical findings of a congenital pericardial defect associated with spontaneous pneumothorax.

Levoatriocardinal Vein Combined with Pulmonary Venous Varix Mimicking Arteriovenous Malformations: A Case Report

The levoatriocardinal vein is an uncommon pulmonary venous abnormality that connects the left atrium or pulmonary vein with the systemic vein. It is distinct from partial anomalous pulmonary venous return in that the former forms a connection with the left atrium through the normal pulmonary vein whereas the latter involves pulmonary venous drainage to the systemic vein. Herein, we describe a case of the levoatriocardinal vein initially misdiagnosed as a pulmonary arteriovenous malformation using chest radiography and chest CT. The levoatriocardinal vein combined with pulmonary venous varix was confirmed using pulmonary angiography.To the best of our knowledge, this unusual coexistence of the levoatriocardinal vein and pulmonary venous varix has not been reported in English literature.

A Case of Coronary Sinus Atresia with a Total Anomalous Cardiac Venous Drainage to the Left Atrium without Persistent Left Superior Vena Cava: Imaging Findings on Cardiac CT

The coronary sinus (CS) is the venous drainage system of the heart. CS ostium atresia is a rarely seen cardiac malformation. Congenital atresia of the CS is usually found together with persistent left superior vena cava (LSVC) and other cardiac malformations. However, isolated congenital atresia of the CS is very rare. We present a rare case of isolated congenital atresia of the CS connecting the left atrium and coronary veins without persistent LSVC in a 58-year-old female.

Incidentally Detected Pericardial Defect in a Patient with Pneumothorax as Confirmed on Video-Assisted Thoracoscopic Surgery

Congenital defects of the pericardium, which are generally asymptomatic, are rare disorders characterized by complete or partial absence of the pericardium. Here, we report a rare case of a 19-year-old male who was incidentally diagnosed with congenital absence of the left pericardium during examination for symptoms of pneumothorax. Chest radiography and CT revealed a collapsed left lung without any evidence of trauma, no unusual findings of free air spaces along the right side of the ascending aorta, heart shifted toward the left side of the thorax, and a shallow chest. Subsequent thoracoscopy confirmed the absence of the left pericardium and displacement of the heart toward the left thoracic cavity. We further discuss the correlation between radiologic images and surgical findings of a congenital pericardial defect associated with spontaneous pneumothorax.

Levoatriocardinal Vein Combined with Pulmonary Venous Varix Mimicking Arteriovenous Malformations: A Case Report

The levoatriocardinal vein is an uncommon pulmonary venous abnormality that connects the left atrium or pulmonary vein with the systemic vein. It is distinct from partial anomalous pulmonary venous return in that the former forms a connection with the left atrium through the normal pulmonary vein whereas the latter involves pulmonary venous drainage to the systemic vein. Herein, we describe a case of the levoatriocardinal vein initially misdiagnosed as a pulmonary arteriovenous malformation using chest radiography and chest CT. The levoatriocardinal vein combined with pulmonary venous varix was confirmed using pulmonary angiography.To the best of our knowledge, this unusual coexistence of the levoatriocardinal vein and pulmonary venous varix has not been reported in English literature.

A Case of Coronary Sinus Atresia with a Total Anomalous Cardiac Venous Drainage to the Left Atrium without Persistent Left Superior Vena Cava: Imaging Findings on Cardiac CT

The coronary sinus (CS) is the venous drainage system of the heart. CS ostium atresia is a rarely seen cardiac malformation. Congenital atresia of the CS is usually found together with persistent left superior vena cava (LSVC) and other cardiac malformations. However, isolated congenital atresia of the CS is very rare. We present a rare case of isolated congenital atresia of the CS connecting the left atrium and coronary veins without persistent LSVC in a 58-year-old female.

The Effects of a Vasodilator on Transluminal Attenuation Gradient at Coronary Computed Tomography Angiography

Objective@#To evaluate the effects of vasodilators on contrast enhancement and transluminal attenuation gradient (TAG) of coronary arteries at coronary computed tomography angiography (CCTA). @*Materials and Methods@#We retrospectively reviewed CCTA scans of patients who underwent double-acquisition CCTA; CCTA without a vasodilator, and CCTA during a intravenous (IV) infusion of nitrate. Among them, we enrolled 19 patients who had no significant atherosclerotic lesions or coronary spasms. In the control group, 28 patients were enrolled who showed normal coronary arteries on CCTA, which was acquired by a conventional method (sublingual vasodilator). We measured the TAG and Hounsfield units for each of the three major epicardial coronary arteries (reported as ‘ProxHU’) and then compared the results between the nitrate administration methods (CT without vasodilator [CT pre], CT with IV vasodilator [CTiv], and CT with sublingual vasodilator [CTsub]). @*Results@#The mean TAG showed a significant difference between the coronary arteries (right coronary artery [RCA] > left anterior descending artery [LAD] > left circumflex artery [LCX], p 0.05). The TAG of CTpre group showed steeper slope than those of vasodilator groups (CTiv and CTsub) on LAD and LCX ([LAD: CTpre = -22.1 ± 6.66, CTiv = -16.76 ± 5.78, and CTsub = -16.47 ± 5.78, p = 0.005], [LCX: CTpre = -31.26 ± 17.43, CTiv = -23.74 ± 14.06, and CTsub = -20.94 ± 12.15, p = 0.051]), while that of RCA showed no significant differences (p = 0.600). When comparing proxHU, CT iv showed higher proxHU than that of CTpre or CTsub, especially on LCX (CTpre = 426.7 ± 68.3, CTiv = 467.9 ± 84.9, and CTsub = 404.9 ± 63.3, p = 0.013). ProxHU showed a negative correlation with TAG on all three of methods (r = -0.280, p < 0.001). @*Conclusion@#TAG in CCTA was significantly affected by vasodilator administration. Both TAG and ProxHU of coronary arteries tend to increase with vasodilator administration on CCTA.

The Effects of a Vasodilator on Transluminal Attenuation Gradient at Coronary Computed Tomography Angiography

Objective@#To evaluate the effects of vasodilators on contrast enhancement and transluminal attenuation gradient (TAG) of coronary arteries at coronary computed tomography angiography (CCTA). @*Materials and Methods@#We retrospectively reviewed CCTA scans of patients who underwent double-acquisition CCTA; CCTA without a vasodilator, and CCTA during a intravenous (IV) infusion of nitrate. Among them, we enrolled 19 patients who had no significant atherosclerotic lesions or coronary spasms. In the control group, 28 patients were enrolled who showed normal coronary arteries on CCTA, which was acquired by a conventional method (sublingual vasodilator). We measured the TAG and Hounsfield units for each of the three major epicardial coronary arteries (reported as ‘ProxHU’) and then compared the results between the nitrate administration methods (CT without vasodilator [CT pre], CT with IV vasodilator [CTiv], and CT with sublingual vasodilator [CTsub]). @*Results@#The mean TAG showed a significant difference between the coronary arteries (right coronary artery [RCA] > left anterior descending artery [LAD] > left circumflex artery [LCX], p 0.05). The TAG of CTpre group showed steeper slope than those of vasodilator groups (CTiv and CTsub) on LAD and LCX ([LAD: CTpre = -22.1 ± 6.66, CTiv = -16.76 ± 5.78, and CTsub = -16.47 ± 5.78, p = 0.005], [LCX: CTpre = -31.26 ± 17.43, CTiv = -23.74 ± 14.06, and CTsub = -20.94 ± 12.15, p = 0.051]), while that of RCA showed no significant differences (p = 0.600). When comparing proxHU, CT iv showed higher proxHU than that of CTpre or CTsub, especially on LCX (CTpre = 426.7 ± 68.3, CTiv = 467.9 ± 84.9, and CTsub = 404.9 ± 63.3, p = 0.013). ProxHU showed a negative correlation with TAG on all three of methods (r = -0.280, p < 0.001). @*Conclusion@#TAG in CCTA was significantly affected by vasodilator administration. Both TAG and ProxHU of coronary arteries tend to increase with vasodilator administration on CCTA.

Carotid Arterial Calcium Scoring Using Upper Airway Computed Tomography in Patients with Obstructive Sleep Apnea: Efficacy as a Clinical Predictor of Cerebrocardiovascular Disease

OBJECTIVE: To evaluate the value of airway computed tomography (CT) in patients with obstructive sleep apnea (OSA) as a predictor of cerebrocardiovascular disease (CCVD) clinically, by quantitatively analyzing carotid arterial calcification (CarAC). MATERIALS AND METHODS: This study included 287 patients aged 40–80 years, who had undergone both polysomnography (PSG) and airway CT between March 2011 and October 2015. The carotid arterial calcium score (CarACS) was quantified using the modified Agatston method on each upper airway CT. The OSA severity was categorized as normal, mild, moderate, and severe using the PSG results. Clinical characteristics, comorbid diseases, and lipid profiles of all patients were analyzed, and the prevalence of CCVDs was investigated during the follow up period (52.2 ± 16.0 months). RESULTS: CCVD occurred in 27 patients (9.3%) at the end of follow-up, and the CCVD-present groups showed a significantly older mean age (57.5 years vs. 54.2 years), higher prevalence of hypertension (59% vs. 34%) and CarAC (51.9% vs. 20.8%), whereas sex, other comorbid diseases, and severity of OSA were not significantly different from the CCVD-absent group. A univariate analysis showed that age, hypertension, incidence of CarAC, and CarACS were risk factors for the occurrence of CCVD events. In a multivariate analysis, the incidence of CarAC was the only independent risk factor for CCVD. CONCLUSION: CarAC is an independent risk factor for CCVD, whereas the severity of OSA is not a contributory risk factor in patients with OSA. Therefore, additional analysis of CarACS based on airway CT scans may be useful for predicting CCVD.

Clinical Applications of Wide-Detector CT Scanners for Cardiothoracic Imaging: An Update

Technical developments in multidetector computed tomography (CT) have increased the number of detector rows on the z-axis, and 16-cm wide-area-coverage CT scanners have enabled volumetric scanning of the entire heart. Beyond coronary arterial imaging, such innovations offer several advantages during clinical imaging in the cardiothoracic area. The wide-detector CT scanner markedly reduces the image acquisition time to less than 1 second for coronary CT angiography, thereby decreasing the volume of contrast material and radiation dose required for the examination. It also eliminates stair-step artifacts, allowing robust improvements in myocardial function and perfusion imaging. Additionally, new imaging techniques for the cardiothoracic area, including subtraction imaging and free-breathing scans, have been developed and further improved by using the wide-detector CT scanner. This article investigates the technical developments in wide-detector CT scanners, summarizes their clinical applications in the cardiothoracic area, and provides a review of the recent literature.

Correlation between Carotid Arterial Calcium Score and Silent Cerebrovascular Lesions in Obstructive Sleep Apnea Patients: by Using Upper Airway CT and Brain MRI

PURPOSE@#To investigate the relationship between carotid arterial calcium score (CarACS) and silent cerebrovascular lesions in patients with obstructive sleep apnea (OSA).@*MATERIALS AND METHODS@#This study involved retrospective evaluation of 60 OSA patients who underwent both upper airway CT and brain MRI. Using polysomnography, several indicators, including apnea index (AI), were used to evaluate the relationship between OSA and silent cerebrovascular lesions. The CarACS was quantified on CT imaging using the modified Agatston method. Silent cerebrovascular lesions were evaluated on brain MRI by grading periventricular hyperintensity (PVH). Various clinical characteristics, including age, were analyzed in each patient.@*RESULTS@#The number of patients per PVH grade 0, 1, 2, 3, and 4 was 26 (43.3%), 14 (23.3%), 14 (23.3%), 4 (6.7%), and 2 (3.3%), respectively. The mean age, hypertension, smoking status, AI, and CarACS were significantly different among PVH groups (Ps < 0.05). In univariate analysis, the presence of carotid arterial calcification (β = 0.483, p < 0.01), CarACS (β = 0.482, p < 0.01), and age (β = 0.360, p < 0.01) showed a significant association with PVH grade. The mean AI and lowest O₂ saturation had statistically weak associations with PVH grade (β = 0.267, p < 0.01; β = −0.219, p < 0.14, respectively). In multivariate analysis, CarACS was the only factor affecting PVH grade (p < 0.04).@*CONCLUSION@#CarACS is associated with the severity of silent cerebrovascular lesions. Therefore, additional analysis of CarACS in OSA patients may provide more information on their cerebrovascular status.

Reliability in Using Routine Coronary CT Angiography with Retrospective Electrocardiographic Gating for the Comprehensive Functional Evaluation of the Left Ventricle

PURPOSE@#To evaluate the feasibility of comprehensive left ventricle (LV) functional parameters on routine coronary computed tomographic angiography (CCTA) based on two-dimensional echocardiography (2DE).@*MATERIALS AND METHODS@#Ninety-nine patients who underwent CCTA accompanied by 2DE were included in the study. The volumetric LV systolic functional parameters were acquired from 10-phase reconstruction of CCTA data. By differentiating the time-LV volume curve by time domain and measuring mitral valvular orifice areas, transmitral time-velocity curves were drawn and the early (E) to late (A) mitral inflow peak velocities ratio (E/A ratio) was acquired. By measuring a longitudinal jerking velocity of the mitral valvular annulus on a four-chamber view, the mitral peak velocity of early filling (E) to early diastolic mitral annular velocity (E') ratio (E/E' ratio) was evaluated. All functional parameters were compared with the 2DE results.@*RESULTS@#The LV end diastolic volume, LV end systolic volume, ejection fraction, stroke volume, cardiac output, and LV myocardial mass measured by CCTA and 2DE showed moderate to strong correlations (r = 0.732, 0.821, 0.416, 0.394, 0.328, and 0.764, respectively; p < 0.05). The E/A and E/E' ratios showed strong correlation between CCTA and echocardiography (r = 0.807 and 0.751, respectively; p < 0.05).@*CONCLUSION@#When CCTA is performed with retrospective electrocardiographic gating, additional information about the LV function can be acquired as reliably as with echocardiography.

Effect of Hybrid Kernel and Iterative Reconstruction on Objective and Subjective Analysis of Lung Nodule Calcification in Low-Dose Chest CT

OBJECTIVE: To evaluate the differences in subjective calcification detection rates and objective calcium volumes in lung nodules according to different reconstruction methods using hybrid kernel (FC13-H) and iterative reconstruction (IR). MATERIALS AND METHODS: Overall, 35 patients with small (< 4 mm) calcified pulmonary nodules on chest CT were included. Raw data were reconstructed using filtered back projection (FBP) or IR algorithm (AIDR-3D; Canon Medical Systems Corporation), with three types of reconstruction kernel: conventional lung kernel (FC55), FC13-H and conventional soft tissue kernel (FC13). The calcium volumes of pulmonary nodules were quantified using the modified Agatston scoring method. Two radiologists independently interpreted the role of each nodule calcification on the six types of reconstructed images (FC55/FBP, FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D). RESULTS: Seventy-eight calcified nodules detected on FC55/FBP images were regarded as reference standards. The calcium detection rates of FC55/AIDR-3D, FC13-H/FBP, FC13-H/AIDR-3D, FC13/FBP, and FC13/AIDR-3D protocols were 80.7%, 15.4%, 6.4%, 52.6%, and 28.2%, respectively, and FC13-H/AIDR-3D showed the smallest calcium detection rate. The calcium volume varied significantly with reconstruction protocols and FC13/AIDR-3D showed the smallest calcium volume (0.04 ± 0.22 mm³), followed by FC13-H/AIDR-3D. CONCLUSION: Hybrid kernel and IR influence subjective detection and objective measurement of calcium in lung nodules, particularly when both techniques (FC13-H/AIDR-3D) are combined.

Bronchogenic Cyst in an Intradiaphragmatic Location: A Case Report

Bronchogenic cysts are congenital lesions usually observed in the mediastinum, near the tracheal carina and middle mediastinum. Herein, we present an exceedingly rare case of intradiaphragmatic bronchogenic cyst with an infectious complication in a 52-year-old man. Chest CT and three-dimensional volume rendered reconstructed images revealed an oval, cystic mass with multiple nodular calcifications, centered in the left diaphragm crus. CT facilitated documentation of the healing process of this rare entity, revealing decrease in size and increase in internal density.

Quantitative Computed Tomography Assessment of Respiratory Muscles in Male Patients Diagnosed with Emphysema

PURPOSE@#The aim of this study was to accurately evaluate the significance and correlation between the clinical severity and the morphologic feature of respiratory muscles in patients with emphysema as noted using computed tomography (CT).@*MATERIALS AND METHODS@#The cross sectional area (CSA) and attenuation of respiratory muscles in the patients with emphysema (n = 71) were subsequently retrospectively reviewed. The clinical severity for the patients was determined by the value of the actual forced expiratory volume in 1 second/forced vital capacity at the pulmonary function test (PFT). The correlation between the CT measurements with visual assessment of emphysema (VAE), and the PFT values were completed and recorded. The multiple linear regression analysis of each CT measurement on the VAE and PFT values was used to determine the most affective parameters among the recorded and identified CT measurements.@*RESULTS@#The CSA of the pectoralis major (p = 0.002) and subsequently the serratus anterior (p = 0.011) were found to be lower in patients with emphysema than as compared to those in the control group. The CSA and the attenuation of respiratory muscles remained significant for its relation for the VAE and PFT values. As noted, both the VAE and PFT values were mostly contributed by the CSA and attenuation of serratus anterior and attenuation of diaphragm crus among all respiratory muscles.@*CONCLUSION@#The CT measurement of the patient's respiratory muscles may reflect clinical and visual severity in the patients with emphysema.

Left Ventricular Functional Parameters and Geometric Patterns in Korean Adults on Coronary CT Angiography with a 320-Detector-Row CT Scanner

OBJECTIVE: To assess the normal reference values of left ventricle (LV) functional parameters in Korean adults on coronary CT angiography (CCTA) with a 320-detector-row CT scanner, and to analyze sex-related differences and correlations with various clinical characteristics. MATERIALS AND METHODS: This study retrospectively enrolled 172 subjects (107 men and 65 women; age, 58 ± 10.9 years; body surface area [BSA], 1.75 ± 0.2 m²) who underwent CCTA without any prior history of cardiac disease. The following parameters were measured by post-processing the CT data: LV volume, LV functional parameters (ejection fraction, stroke volume, cardiac output, etc.), LV myocardial mass, LV inner diameter, and LV myocardial thickness (including septal wall thickness [SWT], posterior wall thickness [PWT], and relative wall thickness [RWT = 2 × PWT / LV inner diameter]). All of the functional or volumetric parameters were normalized using the BSA. The general characteristics and co-morbidities for the enrolled subjects were recorded, and the correlations between these factors and the LV parameters were then evaluated. RESULTS: The LV myocardial thickness (SWT, 1.08 ± 0.18 cm vs. 0.90 ± 0.17 cm, p < 0.001; PWT, 0.91 ± 0.15 cm vs. 0.78 ± 0.10 cm, p < 0.001; RWT, 0.38 ± 0.08 cm vs. 0.33 ± 0.05 cm, p < 0.001), LV volume (LV end-diastolic volume, 112.9 ± 26.1 mL vs. 98.2 ± 21.0 mL, p < 0.001; LV end-systolic volume, 41.7 ± 14.7 mL vs. 33.7 ± 12.2 mL, p = 0.001) and mass (145.0 ± 29.1 g vs. 107.9 ± 20.0 g, p < 0.001) were significantly greater in men than in women. However, these differences were not significant after normalization using BSA, except for the LV mass (LV mass index, 79.6 ± 14.0 g/m² vs. 66.2 ± 11.0 g/m², p < 0.001). The cardiac output and ejection fraction were not significantly different between the men and women (cardiac output, 4.3 ± 1.0 L/min vs. 4.2 ± 0.9 L/min, p = 0.452; ejection fraction, 63.4 ± 7.7% vs. 66.4 ± 7.6%, p = 0.079). Most of the LV parameters were positively correlated with BSA, body weight, and total Agatston score. CONCLUSION: This study provides sex-related reference values and percentiles for LV on cardiac CT and should assist in interpreting results.

Middle East Respiratory Syndrome-Coronavirus Infection: A Case Report of Serial Computed Tomographic Findings in a Young Male Patient

Radiologic findings of Middle East respiratory syndrome (MERS), a novel coronavirus infection, have been rarely reported. We report a 30-year-old male presented with fever, abdominal pain, and diarrhea, who was diagnosed with MERS. A chest computed tomographic scan revealed rapidly developed multifocal nodular consolidations with ground-glass opacity halo and mixed consolidation, mainly in the dependent and peripheral areas. After treatment, follow-up imaging showed that these abnormalities markedly decreased but fibrotic changes developed.