Severe acute respiratory syndrome: thin-section computed tomography features, temporal changes, and clinicoradiologic correlation during the convalescent period

OBJECTIVE: To evaluate thin-section computed tomography findings of patients with severe acute respiratory syndrome (SARS) in the convalescent period and to correlate the results with clinical parameters and lung function tests. METHODS: Ninety-nine severe acute respiratory syndrome patients with persistent changes on follow-up chest radiography were included. One hundred seventy computed tomography examinations at baseline (n=70), 3 months (n=56), and 6 months (n=44) were retrospectively evaluated to determine the extent of ground-glass opacification, reticulation, and total parenchymal involvement. Patients' demographic information, clinical information during treatment, and results of lung function tests at 3 and 6 months were correlated with computed tomography findings. RESULTS: A significant serial improvement in the extent of overall ground-glass opacification, overall reticulation, and total parenchymal involvement was observed (P <0.01). Advanced age, previous intensive care unit admission, mechanical ventilation, alternative treatment, higher peak lactate dehydrogenase, and peak radiographic involvement during treatment showed a positive correlation with overall reticulation and total parenchymal involvement at 6 months. There was a significant negative correlation between overall reticulation and total parenchymal involvement with diffusion capacity adjusted for hemoglobin at 3 and 6 months (P <0.01). CONCLUSION: Lung changes on thin-section computed tomography of severe acute respiratory syndrome patients improved with time during the convalescent period and showed a significant correlation with advanced age, parameters indicating severe illness, and diffusion capacity adjusted for hemoglobin on follow-up.     

Late-stage adult respiratory distress syndrome caused by severe acute respiratory syndrome: abnormal findings at thin-section CT

PURPOSE: To evaluate thin-section computed tomographic (CT) abnormalities in patients in the intensive care unit during the late stage of adult respiratory distress syndrome (ARDS) caused by severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: Eight patients in the late stage of ARDS (ie, more than 2 weeks after onset) were imaged with thin-section CT. Images were evaluated for ground-glass opacification, consolidation, interstitial thickening, evidence of fibrosis, and any other abnormalities. Patient records were reviewed, and relevant respiratory and ventilatory parameters, total steroid dose, and outcome were recorded. RESULTS: All patients received high-dose pulse methylprednisolone (minimum, 2.5 g total), and all patients who received ventilation received low-pressure, low-volume ventilation. Five patients received prolonged mechanical ventilation (for more than 14 days), one received ventilation for 72 hours, and two patients did not receive ventilation. Three patients died, four were discharged from the hospital, and one continued to require ventilation. Ground-glass opacification and interstitial thickening were present at CT in all eight patients. Consolidation was present in six patients. Three patients had evidence of fibrosis. Patients who received long-term ventilation, those who received short-term ventilation, and those who did not receive ventilation had similar pulmonary changes at CT. Pulmonary cysts, most of which were small (<1 cm), were present in five patients. Cysts were present in one patient who received only short-term low-pressure and low-volume ventilation and in one patient who received no mechanical ventilation. CONCLUSION: The CT features of late-stage ARDS caused by SARS are similar to those seen in late-stage ARDS of other causes, with no apparent differences between patients who do and patients who do not receive prolonged mechanical ventilation. The presence of cysts in one patient who received short-term and one patient who received no mechanical ventilation suggests that severe SARS-induced ARDS may independently result in cyst formation.     

Pulmonary sequelae in convalescent patients after severe acute respiratory syndrome: evaluation with thin-section CT

PURPOSE: To prospectively evaluate lung parenchyma on paired inspiration-expiration thin-section computed tomographic (CT) scans in patients recovering from severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: After the institutional review board approved the study and written consent was obtained from patients, 40 patients (25 female, 15 male; mean age, 42.8 years +/- 12.3 [standard deviation]) underwent thin-section CT at 51.8 days +/- 20.2 after onset of SARS symptoms. Twenty of the 40 patients underwent follow-up thin-section CT at 140.7 days +/- 26.7 after symptom onset. Lung findings were scored according to extent and then grouped in three categories (ground-glass opacity, interstitial opacity, and air trapping) for analysis. Mean CT scores for each finding in the various patient subgroups were compared by using the Mann-Whitney test. Clinical parameters and scores were evaluated for correlation by using Spearman rank correlation analysis. Mean scores for each finding were compared between the two serial examinations by using the Wilcoxon matched-pairs signed rank test. RESULTS: Air trapping, ground-glass opacity, and reticulation were found in 37 (92%), 36 (90%), and 28 (70%) of 40 patients, respectively, at initial thin-section CT examination and in 16 (80%), 14 (70%), and 10 (50%) of 20 patients, respectively, at follow-up examination. Scans from patients with adult respiratory distress syndrome (ARDS) had a significantly higher score for ground-glass opacity than did those from patients without ARDS (P = .009). A comparison of scores for the serial thin-section CT examinations indicated a significant reduction in the extent of ground-glass opacity (P < .001) and interstitial opacity (P < .001) but not in that of air trapping (P = .38) at follow-up examination. At initial thin-section CT, scores for ground-glass opacity, interstitial opacity, and air trapping correlated with age; those for ground-glass opacity and air trapping, with peak C-reactive protein level. At the second examination, scores for ground-glass opacity and interstitial opacity correlated with peak lactate dehydrogenase level; that for air trapping, with age and peak C-reactive protein level. CONCLUSION: Thin-section CT scores correlated with clinical and laboratory parameters in patients after SARS. Although ground-glass opacity and interstitial opacity resolve over time, air trapping persists.     

Severe acute respiratory syndrome: radiographic and CT findings

OBJECTIVE: We review the radiographic and CT findings in the lungs of 12 patients with severe acute respiratory syndrome (SARS) in an effort to describe the most common radiologic findings for this disease. CONCLUSION: The most common radiographic findings of SARS patients at presentation are unilateral or bilateral ground-glass opacities or focal unilateral or bilateral areas of consolidation. In hospitalized SARS patients, the abnormalities tend to progress to bilateral air-space consolidation. CT may reveal parenchymal disease in patients whose radiographs show normal results.     

Acute respiratory distress syndrome and acute interstitial pneumonia: comparison of thin-section CT findings

PURPOSE: The purpose of this work was to compare the thin-section CT findings of acute respiratory distress syndrome (ARDS) with those of acute interstitial pneumonia (AIP). METHOD: The thin-section CT scans from 25 patients with ARDS and 25 with AIP were independently assessed by two observers without knowledge of clinical and pathologic data. The presence, extent, and distribution of various CT findings were independently analyzed. RESULTS: Honeycombing was seen more frequently in lobes of patients with AIP (26%) than in lobes with ARDS (8%) (p < 0.001). Compared with patients with ARDS, a greater number of patients with AIP had a predominantly lower lung zone distribution (p < 0.05) and a symmetric distribution (p < 0.05) of the parenchymal abnormalities. CONCLUSION: Patients with AIP have a greater prevalence of honeycombing and are more likely to have a symmetric bilateral distribution and a lower lung zone predominance than patients with ARDS. However, significant overlap exists among the CT findings.     

Prediction of prognosis for acute respiratory distress syndrome with thin-section CT: validation in 44 cases

PURPOSE: To retrospectively evaluate whether the thin-section computed tomographic (CT) appearance has prognostic value for prediction of mortality, number of ventilator-free days (ie, days without mechanical ventilation), and 28-day risk of barotrauma in patients with a clinically early stage of acute respiratory distress syndrome (ARDS) from diverse causes. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Two independent observers who were blinded to patient outcomes retrospectively evaluated the thin-section CT scans obtained within 7 days after clinical ARDS onset in 26 survivors and 18 nonsurvivors. Of 44 patients, there were 37 men and seven women (mean age +/- standard deviation, 61.8 years +/- 15.6). CT findings were graded on a scale of 1-6 that corresponded with consecutive pathologic phases: score of 1, normal attenuation; score of 2, ground-glass attenuation; score of 3, consolidation; score of 4, ground-glass attenuation associated with traction bronchiolectasis or bronchiectasis; score of 5, consolidation associated with traction bronchiolectasis or bronchiectasis; and score of 6, honeycombing. An overall CT score was obtained by adding the six averaged scores (three zones in each lung). Multivariate regression analysis was used to assess the independent predictive value of the CT score. RESULTS: The area of increased attenuation associated with traction bronchiolectasis or bronchiectasis (P = .002), as well as the overall CT score (P = .002), was smaller in survivors than in nonsurvivors. Results of multivariate regression analysis revealed that CT score was independently associated with mortality (P = .006). A CT score of less than 230 enabled prediction of survival with 73% sensitivity and 75% specificity and was associated with both a greater number of ventilator-free days (P = .018) and a lower incidence of barotrauma (P = .013) within 28 days after ARDS onset. CONCLUSION: Extensive thin-section CT abnormalities indicative of fibroproliferative changes were independently predictive of poor prognosis in patients with a clinically early stage of ARDS.     

SARS的CT表现及动态变化

目的 探讨严重急性呼吸综合征的CT表现及动态变化。方法 对60例严重急性呼吸综合征患者进行X线胸片(已有另文报道)和高分辨率CT(HRCT）的动态观察。患者在入院时及入院后连续进行CT观察检查，间隔4～6d。结果 发病初期进行影像检查者25例，CT表现为小片状影像者22例，占88.0％(22／25)；其中类圆形磨玻璃样影20例，占80．0％(20／25)。其余35例在进行影像检查时已发病3d，病变已经有所进展。3d后患者肺部均出现多发大片状影像，其中呈单一磨玻璃样影者10例，占16.7％(10／60)；磨玻璃样影合并实变影者4：5例，占75．0％(45／60)；主要呈肺实变影者5例，占8.3％(5／60)。入院10～14d内病变明显进展者50例，占83.3％(50／60)；病变范围减少者10例，占16．7％(10／60)；合并肺间质增生者4例，占6．7％。结论 HRCT可清楚反映SARS病变的密度、形态和范围，以及显示肺间质增生改变。因而，HRCT可以用于早期诊断和了解病变的动态变化。     

Eosinophilic lung diseases: diagnostic accuracy of thin-section CT in 111 patients

PURPOSE: To determine whether various eosinophilic lung diseases can be differentiated by means of thin-section computed tomography (CT). MATERIALS AND METHODS: Thin-section CT scans in 111 patients with eosinophilic lung diseases-40 with chronic eosinophilic pneumonia, 16 with Churg-Strauss syndrome, 16 with allergic bronchopulmonary aspergillosis (ABPA), 13 with acute eosinophilic pneumonia, 12 with simple pulmonary eosinophilia, 11 with drug-induced eosinophilic pneumonia, and three with hypereosinophilic syndrome-were assessed independently by two observers. The observers recorded the abnormalities, diagnosis, and degree of confidence in the diagnosis. RESULTS: The two observers made a correct first-choice diagnosis on average in 61% of readings. The correct diagnosis was made in 78% of cases of chronic eosinophilic pneumonia; 81%, acute eosinophilic pneumonia; 44%, Churg-Strauss syndrome; 84%, ABPA; 17%, simple pulmonary eosinophilia; 27%, drug-induced eosinophilic pneumonia; and 33%, hypereosinophilic syndrome. The two observers made a correct diagnosis with a high degree of confidence in 36% of readings. There was moderate agreement between the observers for the correct diagnosis (kappa, 0.47) and for the correct diagnosis with a high degree of confidence (kappa, 0.59). CONCLUSION: Although eosinophilic lung diseases often can be differentiated by means of thin-section CT, correlation between CT findings and careful clinical evaluation are required for a definitive diagnosis.     

Severe acute respiratory syndrome: prognostic implications of chest radiographic findings in 52 patients

PURPOSE: To retrospectively assess prognostic implications of radiographic findings in severe acute respiratory syndrome (SARS). MATERIALS AND METHODS: Radiographic findings were reviewed by two radiologists for 52 patients with SARS. On each radiograph, each lung was separated into upper, middle, and lower zones. A four-point scale was used to score extent of SARS-related lesions in each zone; points from all zones were added for a cumulative score. Patient sex, age, comorbidities, duration of developing lesions, lesion score for each radiograph, need for mechanical ventilation, and percentage of lung affected were compared between patients who died (n = 20) and survivors (n = 32). Continuous and categorical variables were analyzed with Mann-Whitney test and Fisher exact or chi(2) test, respectively. RESULTS: Survival and mortality groups showed no significant differences with respect to patient sex, duration of SARS-related lesions, development of lesion shifting, and acute respiratory distress syndrome. Patients who died were significantly older (mean +/- standard deviation, 56.9 years +/- 17.2 vs 40.4 years +/- 16.6; P =.002) and had higher frequency of comorbid lung illnesses (nine of 20 vs two of 32, P =.001), maximal lesion extent score of 7 or higher (20 of 20 vs five of 32, P <.001), involvement of four or more lung zones (17 of 20 vs four of 32, P <.001), bilateral lung involvement (19 of 20 vs 14 of 32, P <.001), need for mechanical ventilation (18 of 20 vs two of 32, P <.001), and higher percentage of affected areas (41.5% +/- 8.6 vs 16.4% +/- 10.0, P <.001) than those of survivors. CONCLUSION: On chest radiographs, maximal SARS-related lesion extent score of 7 or higher is a strong predictor of mortality, especially in patients with comorbid lung illnesses and involvement of four or more lung zones.     

Severe acute respiratory syndrome in a naval diver

Severe acute respiratory syndrome (SARS) is a highly infectious, rapidly progressive, emerging disease. Early diagnosis and preventive measures are key for treatment and minimization of secondary spread. In the context of the armed forces, aggressive containment measures are essential to prevent an outbreak. In this study, we present the first reported case, to our knowledge, of SARS in a naval diver. The special physical requirements for divers and the potential complications associated with deep sea diving necessitate extensive investigation before certification of fitness for diving after SARS. In the early recovery period, potential problems during diving are caused by inadequate lung ventilation in relation to exercise level and increased breathing resistance attributable to weak respiratory muscles, with corresponding risk of hypoxia and hypercapnia, as well as decreased ability to respond to nonrespiratory problems during diving. Problems in the late recovery period include increased risk of diving complications (such as pulmonary barotrauma) resulting from fibrosis and scarring within the lung parenchyma, which are known complications of SARS. From our experience, we suggest that computed tomographic scans of the thorax, lung function tests, and careful follow-up monitoring should play a vital role in the assessment of patients during the convalescent period, before certification of fitness to dive.     

重症急性呼吸综合征——传染性非典型肺炎

2003年初春在东南亚先后出现非典型肺炎(Atypical pneumonia,AP)发病病例,2003年2月28日卡罗.乌尔巴尼(CarLoUrbani)首先在越南调研中提出是一种新的传染病,向WHO报告并提出有关防疫措施,WHO建议称之为重症急性呼吸综合征(Se-vere acute respiratory syndrome,SAILS)。     

Oleic acid-induced lung injury: thin-section CT evaluation in dogs

PURPOSE: To validate lung attenuation measurements for quantifying extravascular lung water in oleic acid-induced pulmonary edema, compare subjective assessment with attenuation measurements, and compare this permeability-type pulmonary edema with hydrostatic-type pulmonary edema. MATERIALS AND METHODS: Thin-section computed tomography (CT) and pulmonary hemodynamic examinations were performed sequentially in six dogs before and after intravenous administration of 0.08 mg of oleic acid per kilogram of body weight. Extravascular lung water and pulmonary capillary pressure were measured. Results were compared with those reported in a canine model of hydrostatic edema. RESULTS: Oleic acid induced a progressive increase in extravascular lung water without a change in capillary pressure, which indicated pure permeability-type edema. Ground-glass opacification was detected as soon as extravascular lung water increased. Lung attenuation was highly correlated to extravascular lung water (r = 0.76, P<.001), as in hydrostatic edema, but was characterized by an almost absent gravitational gradient. CONCLUSION: Thin-section CT is sensitive for early detection and quantification of oleic acid-induced pulmonary edema in a canine model. Different from early canine hydrostatic edema, which is characterized by a gravitational gradient, early oleic acid-induced pulmonary edema in a supine dog is characterized by nearly homogeneous distribution, except for ventral sparing.     

Facial canal anatomy in patients with microtia: evaluation of the temporal bones with thin-section CT

PURPOSE: To ascertain the location of the facial nerve in patients with microtia by using thin-section computed tomography (CT). MATERIALS AND METHODS: Thin-section CT was performed in 66 ears of patients with microtia (unilateral, n = 12; bilateral, n = 34) and mandibulofacial dysostosis (MFD, n = 20). Findings were compared with those in 22 ears with normal auricles (control group) by using the Dunnett two-sided t test. RESULTS: The facial nerve at the mastoid portion in patients with MFD was 2 mm more lateral and 3 mm more anterior than that in control subjects (P <.01). The same portion in patients with microtia was 3 mm more anterior than that in the control subjects (P <.01). The distance between the facial nerve and the most lateral point of the temporal bone in patients with MFD was 10 mm shorter and that in patients with bilateral microtia was 3 mm shorter than that in the control subjects (P <.01). CONCLUSION: The facial nerve in patients with microtia was not more lateral from the Bill bar (vertical crest) than that in control subjects. The facial nerve in patients with MFD was different from that in patients with microtia who had no other head anomalies.     

Organizing pneumonia: perilobular pattern at thin-section CT

PURPOSE: To describe the appearance and frequency of a perilobular pattern at thin-section computed tomography (CT) in patients with organizing pneumonia. MATERIALS AND METHODS: Thin-section CT scans of 21 consecutive patients with cryptogenic organizing pneumonia were retrospectively reviewed. Two thoracic radiologists in consensus recorded the presence and distribution of the CT abnormalities (consolidation, ground-glass opacification, nodules, bandlike opacities, interlobular septal thickening, and findings of fibrosis), with a particular focus on the presence and predominant location of the perilobular pattern, that is, a poorly defined arcadelike or polygonal appearance. RESULTS: The perilobular pattern was present in 12 (57%) of 21 patients, 10 of whom had five or more perilobular opacities. Other CT features were consolidation (20 patients, 95%), which was predominantly a subpleural and/or peribronchial distribution in 17 patients, and ground-glass opacification (18 patients, 86%). Bandlike opacities and interlobular septal thickening were observed in four patients and one patient, respectively. The perilobular pattern abutted the pleural surface in 10 of 12 patients and was surrounded by aerated lung parenchyma in 11 of 12 patients. There was no obvious relationship between perilobular opacities and CT findings indicative of established fibrosis. CONCLUSION: A perilobular pattern was present in more than half of the patients, along with the expected thin-section CT features of organizing pneumonia.