Early detection of pneumonia in febrile neutropenic patients: use of thin-section CT

OBJECTIVE

The purpose of this study was to evaluate the usefulness of thin-section CT for early detection of pneumonia in neutropenic patients with an unknown site of infection and normal or nonspecific findings on chest radiographs.

SUBJECTS AND METHODS

Eighty-seven patients with febrile neutropenia that persisted for more than 2 days despite empiric antibiotic treatment underwent 146 prospective examinations. If findings on chest radiographs were normal (n = 126) or nonspecific (n = 20), thin-section CT (1-mm collimation, 10-mm increment) was done. If thin-section CT scans showed opacities, bronchoalveolar lavage was recommended.

RESULTS

Findings on chest radiographs were nonspecific for pneumonia in 20 (14%) of 146 cases, and CT findings in those cases were suggestive of pneumonia. Microorganisms were detected in 11 of those 20 cases. Seven of the 11 cases were not optimally treated before CT diagnosis, the other four were sufficiently treated. Findings on chest radiographs and thin-section CT scans were normal in 56 (38%) of 146 cases. In 70 (48%) of 146 cases, findings on chest radiographs were normal, whereas findings on thin-section CT scans were suggestive of pneumonia. Microorganisms were detected in 30 of the 70 cases. Nineteen of 30 cases were not optimally treated before CT, whereas the other 11 cases were sufficiently treated before CT. In 22 (31%) of these 70 cases, an opacity was observed on the chest radiograph during the 7 days after the CT study. Only three (5%) of 56 pneumonias occurred during the first 7 days after thin-section CT studies with normal findings (p < .005). Additional risk factors for pneumonia occurring later that were detectable on chest radiographs were poorly defined nodules (p < .05), consolidation (p < .05), and younger age (p < .05).

CONCLUSION

Thin-section CT scans show findings suggestive of pneumonia about 5 days earlier than chest radiographs show suggestive findings. When thin-section CT scans show findings suggestive of pneumonia, the probability of pneumonia being detected on chest radiographs during the 7-day follow-up is 31%, whereas the probability is only 5% when the findings on the prior thin-section CT scan were normal (p < .005). All neutropenic patients with fever of unknown origin and normal findings on chest radiographs should be examined with thin-section CT.

Prediction of pneumonia in outpatients with acute cough--a statistical approach

Cough is the fifth most common reason for physician visits, but data on acute cough have rarely been collected in a standardized manner and have not been analyzed in a multivariate fashion. We report data on 1819 patients presenting with cough, all of whom received a standardized history and physical, and a chest X-ray. Only 48 (2.6%) were found to have an acute radiographic infiltrate (pneumonia). The prevalence of common signs and symptoms is shown for the patients with and without pneumonia. Thirty-two of these findings were significant predictors of pneumonia (p less than 0.05, one-tailed). These 32 did not include some of the expected predictors of pneumonia and did include some predictors not previously described in the literature. A diagnostic rule is developed which identifies pneumonia patients with 91% sensitivity and 40% specificity, or 74% sensitivity and 70% specificity. The study results suggest that many pneumonias could be predicted based only on the patients histories. Physician visits to determine physical findings and chest X-rays might be avoided by telephone triage, with substantial cost savings.

Association of radiologically ascertained pneumonia before age 3 yr with asthmalike symptoms and pulmonary function during childhood: a prospective study

Epidemiologic evidence suggests an association between reports of pneumonia in early life and the subsequent development of diminished lung function. However, no studies are available in which the diagnosis of pneumonia was based on radiologic evidence. Lower respiratory illnesses with or without a radiologically confirmed diagnosis of pneumonia were assessed in a study of 888 children enrolled at birth. Pulmonary function tests, markers of atopy, asthma diagnosis, and prevalence of respiratory symptoms were assessed at different ages between birth and 11 yr. Incidence of pneumonia during the first 3 yr of life was 7.4%. Respiratory syncytial virus was the most frequent agent identified both in children with pneumonia and in those with lower respiratory tract illness (LRI) without pneumonia (36.4% versus 35.6%, respectively). Children with a diagnosis of pneumonia were more likely to have physician-diagnosed asthma and current wheezing at ages 6 and 11 yr than were those who had no LRIs. When compared with children without LRIs, those with a diagnosis of pneumonia had lower levels of maximal flows at FRC at mean age of 2 mo (albeit not significantly) and at age 6 yr, and lower levels of FEV1 and FEF25-75 at age 11 yr. These deficits were independent of known confounders, including wheezing at the time of study, and were partly and significantly reversed after administration of a bronchodilator. We conclude that children with radiologically confirmed pneumonia have diminished airway function that is probably present shortly after birth. These deficits are at least in part due to alterations in the regulation of airway muscle tone.

Reliability of the chest radiograph in the diagnosis of lower respiratory infections in young children

OBJECTIVE

This study was conducted to determine the reliability of detecting features and making diagnoses of lower respiratory infections from chest radiograms in young infants.

METHODS

Forty chest radiograms of infants younger than 6 months of age admitted with lower respiratory tract infection to a tertiary care pediatric hospital were independently reviewed on two separate occasions by three pediatric radiologists blinded to the patients' clinical diagnoses. For each radiograph the radiologists noted whether a feature was present, absent or equivocal on a standardized form. The features examined were hyperinflation, peribronchial thickening, perihilar linear opacities, atelectasis and consolidation. On the same form each radiologist indicated whether the radiograph was normal or showed airways and/or airspace disease. Within and between observer agreement were calculated by the average weighted kappa statistic.

RESULTS

Within observer agreement for the radiologic features of hyperinflation, peribronchial wall thickening, perihilar linear opacities, atelectasis and consolidation were 0.85, 0.76, 0.87, 0.86 and 0.91, respectively. The between observer kappa results for these features were 0.83, 0.55, 0.82, 0.78 and 0.79, respectively. The within and between observer kappa statistics for interpretation of the radiographic features were best for airspace disease (within, 0.92; between, 0.91), and lower for normal (within, 0.80; between, 0.66) radiogram and for airways disease (within, 0.68; between, 0.48). The presence of consolidation was highly correlated with a diagnosis of airspace disease by all three radiologists.

CONCLUSIONS

Clinicians basing the diagnosis of lower respiratory infections in young infants on radiographic diagnosis should be aware that there is variation in intraobserver and interobserver agreement among radiologists on the radiographic features used for diagnosis. There is also variation in how specific radiologic features are used in interpreting the radiogram. However, the cardial finding of consolidation for the diagnosis of pneumonia appears to be highly reliable.

Pneumonia and ARDS in patients receiving mechanical ventilation: diagnostic accuracy of chest radiography

This study was done to evaluate the diagnostic accuracy of bedside chest radiography for pneumonia, adult respiratory distress syndrome (ARDS), or both in patients receiving mechanical ventilation. The series consisted of 40 patients; diagnostic accuracy was defined as the area under the receiver operating characteristic curve. Overall diagnostic accuracy for ARDS was 0.84. Overall diagnostic accuracy for pneumonia was 0.52. Review of previous radiographs and knowledge of clinical data did not enhance diagnostic accuracy for ARDS or pneumonia. Diagnostic accuracy for pneumonia was minimally reduced when ARDS was present. There was an increase in false-negative results because the diffuse areas of increased opacity in ARDS obscured the radiographic features of pneumonia. The authors conclude that chest radiography is of limited value for the diagnosis of pneumonia in patients receiving mechanical ventilation. The high false-negative and false-positive ratings for pneumonia resulted in a low diagnostic accuracy. The high diagnostic accuracy for ARDS was primarily due to the well-defined radiographic appearance of ARDS and few false-positive ratings.

Tracheobronchial foreign bodies in children: importance of accurate history and plain chest radiography in delayed presentation

AIM

To evaluate the factors associated with delayed diagnosis of foreign body aspiration (FBA) in children and to compare clinical, radiological and bronchoscopic findings in the patients with suspected FBA.

MATERIAL AND METHODS

The medical records of 214 children who underwent bronchoscopy for suspected FBA were reviewed. The data were analysed in three groups: the patients with negative bronchoscopy for FBA (group I), early (group II) and delayed diagnosis (group III).

RESULTS

The majority of the patients with FBA were between 1 and 3 years of age. Choking episodes, coughing and decreased breath sounds were determined in a significantly higher number of the patients with FBA. The plain chest radiography revealed radio-opaque foreign bodies (FBs) in 19.7% of all patients with FBA. Emphysema was more common in children with FBA. Clinical and radiological findings of pneumonia and atelectasis were significantly more common in the groups with negative bronchoscopy and with delayed diagnosis (p < 0.01). The FBs were most frequently of vegetable origin, such as seeds and peanuts. A significant tissue reaction with inflammation was more common in the delayed cases.

CONCLUSION

To prevent delayed diagnosis, characteristic symptoms, signs and radiological findings of FBA should be checked in all suspected cases. As clinical and radiological findings of FBA in delayed cases may mimic other disorders, the clinician must be aware of the likelihood of FBA. Regardless of radiological findings, bronchoscopy should be considered in patients with an appropriate history.

Drug-induced lung disease: high-resolution CT and histological findings

AIM

To compare the parenchymal high-resolution computed tomography (HRCT) appearances with histological findings in patients with drug-induced lung disease and to determine the prognostic value of HRCT.

MATERIALS AND METHODS

Drug history, HRCT features, histological findings and outcome at 3 months in 20 patients with drug induced-lung disease were reviewed retrospectively. The HRCT images were assessed for the pattern and distribution of abnormalities and classified as most suggestive of interstitial pneumonitis/fibrosis, diffuse alveolar damage (DAD), organizing pneumonia (OP) reaction, or a hypersensitivity reaction.

RESULTS

On histopathological examination there were eight cases of interstitial pneumonitis/fibrosis, five of DAD, five of OP reactions, one of hypersensitivity reaction and one of pulmonary eosinophilia. The most common abnormalities on HRCT were ground-glass opacities (n = 17), consolidation (n = 14), interlobular septal thickening (n = 15) and centrilobular nodules (n = 8). HRCT interpretation and histological diagnosis were concordant in only nine (45%) of 20 patients. The pattern, distribution, and extent of HRCT abnormalities were of limited prognostic value: all eight patients with histological findings of OP, hypersensitivity reaction, or eosinophilic infiltrate improved on follow-up compared to only five of 13 patients with interstitial pneumonitis/fibrosis or DAD.

CONCLUSION

In many cases of drug-induced lung injury HRCT is of limited value in determining the histological pattern and prognosis.

The rational clinical examination. Does this infant have pneumonia?

Acute lower respiratory tract illness is common among children seen in primary care. We reviewed the accuracy and precision of the clinical examination in detecting pneumonia in children. Although most cases are viral, it is important to identify bacterial pneumonia to provide appropriate therapy. Studies were identified by searching MEDLINE from 1982 to 1995, reviewing reference lists, reviewing a published compendium of studies of the clinical examination, and consulting experts. Observer agreement is good for most signs on the clinical examination. Each study was reviewed by 2 observers and graded for methodologic quality. There is better agreement about signs that can be observed (eg, use of accessory muscles, color, attentiveness; kappa, 0.48-0.66) than signs that require auscultation of the chest (eg, adventitious sounds; kappa, 0.3). Measurements of the respiratory rate are enhanced by counting for 60 seconds. The best individual finding for ruling out pneumonia is the absence of tachypnea. Chest indrawing, and other signs of increased work of breathing, increases the likelihood of pneumonia. If all clinical signs (respiratory rate, auscultation, and work of breathing) are negative, the chest x-ray findings are unlikely to be positive. Studies are needed to assess the value of clinical findings when they are used together.

Lung ultrasound for the diagnosis of pneumonia in adults: A meta-analysis

BACKGROUND

Pneumonia is a common and serious infectious disease that can cause high mortality. The role of lung ultrasound (LUS) in the diagnosis of pneumonia is becoming more and more important.

METHODS

In the present study, we collected existing evidence regarding the use of LUS to diagnose pneumonia in adults and conducted a systematic review to summarize the technique's diagnostic accuracy. We specifically searched the Cochrane Central Register of Controlled Trials (CENTRAL), PubMed, and Embase databases and retrieved outcome data to evaluate the efficacy of LUS for the diagnosis of pneumonia compared with chest radiography or chest computed tomography. The pooled sensitivity (SEN) and specificity (SPE) were determined using the Mantel-Haenszel method, and the pooled diagnostic odds ratio (DOR) was determined using the DerSimonian-Laird method. We also assessed heterogeneity of sensitivity, specificity, and diagnostic odds ratio using the Q and I statistics.

RESULTS

Twelve studies containing 1515 subjects were included in our meta-analysis. The SEN and SPE were 0.88 (95% CI: 0.86-0.90) and 0.86 (95% CI: 0.83-0.88), respectively. The pooled negative likelihood ratio (LR) was 0.13 (95% CI: 0.08-0.23), the positive LR was 5.37 (95% CI: 2.76-10.43), and the DOR was 65.46 (95% CI: 29.24-146.56). The summary receiver operating characteristic curve indicated a relationship between sensitivity and specificity. The area under the curve for LUS was 0.95.

CONCLUSION

LUS can help to diagnose adult pneumonia with high accuracy.

Clinical overlap between malaria and severe pneumonia in Africa children in hospital

Data collected from 200 children admitted to a hospital on the Kenyan coast who met a broad definition of severe acute respiratory infection (ARI) indicated that simple clinical signs alone are unable absolutely to distinguish severe ARI and severe malaria. However, laboratory data showed that marked differences exist in the pathophysiology of unequivocal malaria and unequivocal ARI. Children in the former group had a higher mean oxygen saturation (97 vs. 94, P < 0.001), mean blood urea level (5.3 vs. 1.9 mmol/L, P < 0.001) and geometric mean lactate level (4.5 vs. 2.1 mmol/L, P < 0.001), and lower mean haemoglobin level (5.3 vs. 9.0 g/dL, P < 0.001) and base excess (-9.4 vs. -2.6, P < 0.001) than those in the latter group. Using these discriminatory variables it was estimated that up to 45% of children admitted with respiratory signs indicative of severe ARI probably had malaria as the primary diagnosis. Radiological examination supported this conclusion, indicating that pneumonia characterized by consolidation was uncommon in children with respiratory signs and a high malarial parasitaemia (> or = 10,000/microliters). There is no specific radiological sign of severe malaria. In practice, all children with respiratory signs warranting hospital admission in a malaria endemic area should be treated for both malaria and ARI unless blood film examination excludes malaria. In those with malaria and clinical evidence of acidosis, but no crackles, antibodies may be withheld while appropriate treatment for dehydration and anaemia is given. However, if clinical improvement is not rapid, antibiotics should be started.

Diffuse infiltrative lung disease: a new scheme for description

A scheme was devised for semiquantitative description of the diffuse infiltrative lung diseases using the graphic terminology of the International Labour Office and Union Internationale Contre le Cancer (ILO/UC) classification. Conventions for grading the type (rounded or "pqr" and irregular or "stu"), severity (profusion in 12 steps), localization of opacities, and pleural disease were retained. Modifications included: (a) a third group of opacities, called "xyz," corresponding to reticulonodular patterns; (b) "ground glass" (alveolar) patterns, subdivided into 7 types by character and location; (c) notations for severity of emphysema; and (d) hilar node enlargement. This initial study concerned diagnostic aspects and therefore was limited to 365 cases proved by open biopsy. When this scheme was used without any knowledge of clinical data, the first two radiologic diagnostic choices corresponded with the principal histologic diagnosis in 50% of cases. The biopsy diagnosis was mentioned among the first three choices in 78% of cases. It is concluded that this classification provides an understandable and quantifiable system of communication and a tool for teaching, clinical research, and epidemiologic studies.

Randomised controlled trial of clinical outcome after chest radiograph in ambulatory acute lower-respiratory infection in children

BACKGROUND

When available, chest radiographs are used widely in acute lower-respiratory-tract infections in children. Their impact on clinical outcome is unknown.

METHODS

522 children aged 2 to 59 months who met the WHO case definition for pneumonia were randomly allocated to have a chest radiograph or not. The main outcome was time to recovery, measured in a subset of 295 patients contactable by telephone. Subsidiary outcomes included diagnosis, management, and subsequent use of health facilities.

FINDINGS

There was a marginal improvement in time to recovery which was not clinically significant. The median time to recovery was 7 days in both groups (95% CI 6-8 days and 6-9 days in the radiograph and control groups respectively, p=0.50, log-rank test) and the hazard ratio for recovery was 1.08 (95% CI 0.85-1.34). This lack of effect was not modified by clinicians' experience and no subgroups were identified in which the chest radiograph had an effect. Pneumonia and upper-respiratory infections were diagnosed more often and bronchiolitis less often in the radiograph group. Antibiotic use was higher in the radiograph group (60.8% vs 52.2%, p=0.05). There was no difference in subsequent use of health facilities.

INTERPRETATION

Chest radiograph did not affect clinical outcome in outpatient children with acute lower-respiratory infection. This lack of effect is independent of clinicians' experience. There are no clinically identifiable subgroups of children within the WHO case definition of pneumonia who are likely to benefit from a chest radiograph. We conclude that routine use of chest radiography is not beneficial in ambulatory children aged over 2 months with acute lower-respiratory-tract infection.

The radiographic resolution of Streptococcus pneumoniae pneumonia

To determine the characteristics of the radiographic resolution of bacteremic Streptococcus pneumoniae pneumonia we examined serial chest roentgenograms in 72 patients. Consolidation disappeared in all patients by eight to 10 weeks; volume loss (9 per cent), plural disease (9 per cent), and stranding (19 per cent) often persisted beyond eight weeks. Resolution occurred earlier in patients less than 50 years old (P less than 0.05) and in the absence of alcoholism and underlying airways disease regardless of age (P less than 0.05). Delayed clearing occurred when these complicating factors were present in patients over 50. Lung cancer was not responsible for delayed resolution of pneumonia. We conclude that an appropriate interval for serial radiographic examinations after therapy for pneumococcal pneumonia is six weeks.

Clinical predictors of pneumonia as a guide to ordering chest roentgenograms

To develop criteria for a more efficient approach to the ordering of chest roentgenograms, patients with fever or respiratory symptoms who were being evaluated with this diagnostic test were prospectively monitored. During a six-month period, residents working in a pediatric emergency room collected data on 136 children, 3 months to 15 years of age. Pneumonia, defined by appropriate abnormal chest roentgenographic findings, occurred in 19 per cent. Of the 29 single symptoms or signs examined, the variable which was the best predictor of pneumonia was tachypnea. In addition, a cluster of pulmonary findings was also a good index, for pneumonia. If these clinical criteria had been applied to the patients under investigation, the number of chest roentgenograms obtained would have been reduced by 30 per cent.

CT appearance of acute radiation-induced injury in the lung

To determine how soon radiation-induced lung injury is detectable, to compare the CT findings with those on chest radiographs, and to observe the appearance of the abnormality during the acute phase, we performed 83 CT studies in 17 radiotherapy patients at relatively short intervals. All 17 patients received fractionated radiotherapy to the thorax with a large irradiated lung volume. The CT findings were variable; pulmonary infiltrates were homogeneous, patchy, or discrete. CT abnormalities were evident in 15 of 17 cases within 16 weeks after radiotherapy; in 13 of these it was detected within 4 weeks. In three of these 15 cases, no abnormality was detected on chest radiographs, and in three other cases, the change was observed much later on chest radiographs than on CT scans. In the other nine cases, abnormalities were detected simultaneously on CT scans and chest radiographs. In four cases, extensive radiation pneumonitis was observed on CT, but in two of these, the change was misdiagnosed on the chest radiograph. We conclude that CT is useful in the detection of acute radiation-induced pulmonary disease.

Identification of COVID-19 samples from chest X-Ray images using deep learning: A comparison of transfer learning approaches

BACKGROUND

The novel coronavirus disease 2019 (COVID-19) constitutes a public health emergency globally. The number of infected people and deaths are proliferating every day, which is putting tremendous pressure on our social and healthcare system. Rapid detection of COVID-19 cases is a significant step to fight against this virus as well as release pressure off the healthcare system.

OBJECTIVE

One of the critical factors behind the rapid spread of COVID-19 pandemic is a lengthy clinical testing time. The imaging tool, such as Chest X-ray (CXR), can speed up the identification process. Therefore, our objective is to develop an automated CAD system for the detection of COVID-19 samples from healthy and pneumonia cases using CXR images.

METHODS

Due to the scarcity of the COVID-19 benchmark dataset, we have employed deep transfer learning techniques, where we examined 15 different pre-trained CNN models to find the most suitable one for this task.

RESULTS

A total of 860 images (260 COVID-19 cases, 300 healthy and 300 pneumonia cases) have been employed to investigate the performance of the proposed algorithm, where 70% images of each class are accepted for training, 15% is used for validation, and rest is for testing. It is observed that the VGG19 obtains the highest classification accuracy of 89.3% with an average precision, recall, and F1 score of 0.90, 0.89, 0.90, respectively.

CONCLUSION

This study demonstrates the effectiveness of deep transfer learning techniques for the identification of COVID-19 cases using CXR images.

Occult pneumonias: empiric chest radiographs in febrile children with leukocytosis

STUDY OBJECTIVE

We sought to determine the incidence of radiographic findings of pneumonia in highly febrile children with leukocytosis and no clinical evidence of pneumonia or other major infectious source.

METHODS

We conducted a prospective cohort study at a large urban pediatric hospital. Clinical practice guidelines for the use of chest radiography in febrile children were established by the emergency medicine attending staff. All records of emergency department patients with leukocytosis (WBC count >/= 20, 000/mm3), triage temperature 39.0 degreesC or higher, age 5 years or less were reviewed daily for 12 months. Physicians completed a questionnaire to note the diagnosis, the presence of respiratory symptoms and signs, and the reason for the chest radiograph (if one was obtained). Patients were excluded for immunodeficiency, chronic lung disease, or major bacterial sources of infection other than pneumonia. Pneumonia was defined by an attending radiologist's reading of the radiograph.

RESULTS

We studied 278 patients. Chest radiographs were obtained in 225 for the following reasons: 79 because of respiratory findings suggestive of pneumonia and 146 because of leukocytosis and no identifiable major source of infection. Fifty-three patients did not undergo radiography. Pneumonia was found in 32 of 79 (40%; 95% confidence interval, 20% to 52%) of those with findings suggestive of pneumonia and in 38 of 146 (26%; 95% confidence interval, 19% to 34%) of those without clinical evidence of pneumonia. If patients who did not have a radiograph are assumed to not have pneumonia, the minimum estimate of occult pneumonia was 38 of 199 patients (19%; 95% confidence interval, 14% to 25%).

CONCLUSION

Empiric chest radiographs in highly febrile children with leukocytosis and no findings of pneumonia frequently reveal occult pneumonias. Chest radiography should be considered a routine diagnostic test in children with a temperature of 39 degreesC or greater and WBC count of 20,000/mm3 or greater without an alternative major source of infection.

Aetiology of community-acquired pneumonia in children treated in hospital

Viral and bacterial antigen and antibody assays were prospectively applied to study the microbial aetiology of community-acquired pneumonia in 195 hospitalised children during a surveillance period of 12 months. A viral infection alone was indicated in 37 (19%), a bacterial infection alone in 30 (15%) and a mixed viral-bacterial infection in 32 (16%) patients. Thus, 46% of the 69 patients with viral infection and 52% of the 62 patients with bacterial infection had a mixed viral and bacterial aetiology. Respiratory syncytial virus (RSV) was identified in 52 patients and Streptococcus pneumoniae in 41 patients. The next common agents in order were non-classified Haemophilus influenzae (17 cases), adenoviruses (10 cases) and Chlamydia species (8 cases). The diagnosis of an RSV infection was based on detecting viral antigen in nasopharyngeal secretions in 79% of the cases. Pneumococcal infections were in most cases identified by antibody assays; in 39% they were indicated by demonstrating pneumococcal antigen in acute phase serum. An alveolar infiltrate was present in 53 (27%) and an interstitial infiltrate in 108 (55%) of the 195 patients. The remaining 34 patients had probable pneumonia. C-reactive protein (CRP), erythrocyte sedimentation rate and total white blood cell count were elevated in 25%, 40% and 36% of the patients, respectively. CRP was more often elevated in patients with bacterial infection alone than in those with viral or mixed viral-bacterial infections. No other correlation was seen between the radiological or laboratory findings and serologically identified viral, bacterial or mixed viral-bacterial infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Sonographic diagnosis and follow-up of pneumonia: a prospective study

BACKGROUND

Although transthoracic ultrasound offers several important advantages as diagnostic imaging technique in pleural and pulmonary conditions, its significance for the diagnosis and monitoring of pneumonia has yet to be established.

OBJECTIVES

To identify sonographic features associated with pneumonia at admission and during the course of the disease under treatment.

METHODS

Thirty patients (12 females, 18 males; median age 65.5 years) with X-ray-proven pneumonia underwent transthoracic sonography (TS) on day 0, between days 1 and 3, 4 and 7, 8 and 14, 15 and 21, and after day 21. TS was assessed according to: number, location, shape, echogenicity, echotexture, echostructure, breath-depending movement, size of pneumonic lesions, bronchoaerogram, fluid bronchogram, superficial fluid alveologram, necrotic areas, vascularity and incidence of local and/or basal pleural effusion.

RESULTS

Thirty-three pneumonic infiltrates were eligible for analysis in 30 patients. In 57% (17/30), the likely pathogenic microorganism was identified. Pneumonia was recognized as a hypoechoic area of varying size (mean size between 33.7 x 9.38 and 91.2 x 45.3 mm) and shape, with irregular and blurred margins along with a nonhomogeneous echotexture. The most characteristic feature was a positive bronchoaerogram (32/33). Sixty-one percent (20/33) revealed basal and 9% (3/33) local effusion. During follow-up, lesions decreased in size or disappeared (30/33) or decreased in number (4/9). The bronchoaerogram became less pronounced (13/32), basal pleural effusion either diminished (7/20) or dissipated (7/20), as did localized effusion (3/3). In 30 cases, the course of pneumonia was comparable using X-ray and TS.

CONCLUSIONS

TS is a noninvasive technique for the diagnosis and follow-up of patients with pneumonia.

Pulmonary infections after bone marrow transplantation: high-resolution CT findings in 111 patients

OBJECTIVE

The purpose of this study was to review the high-resolution CT findings in patients with pulmonary infection after bone marrow transplantation and to determine distinguishing features among the various types of infection.

MATERIALS AND METHODS

This study included 111 consecutive bone marrow transplant recipients who had documented pulmonary infection, high-resolution CT of the chest performed within 24 hr of the beginning of symptoms, and proven diagnosis within 1 week of the onset of symptoms. Two radiologists analyzed the CT scans and reached final decisions regarding the findings by consensus. Statistical analysis was performed using the Fisher's exact test and multivariate analysis; a p value of less than 0.05 was considered statistically significant.

RESULTS

The pulmonary infections were due to viruses (n = 57), bacteria (n = 26), fungi (n = 21), and protozoa (n = 1). Six patients had more than one organism responsible for the infection. Nodules that were 1 cm or more in diameter were seen in 13 (62%) of 21 patients with fungal pneumonia, five (19%) of 26 patients with bacterial pneumonia (p = 0.0059), three (10%) of 30 with respiratory syncytial virus (RSV) pneumonia (p = 0.0001), and three (14%) of 22 with cytomegalovirus pneumonia (p = 0.0016). The halo sign was present in 10 of 21 patients with fungal pneumonia, two of 26 with bacterial pneumonia (p = 0.0026), three of 30 with RSV pneumonia (p = 0.0036), and one of 22 with cytomegalovirus pneumonia (p = 0.0015). There was no statistically significant difference in the prevalence of the other CT patterns including small nodules, ground-glass attenuation, and air-space consolidation among viral, bacterial, and fungal infections (all p > 0.05).

CONCLUSION

The presence of large nodules and visualization of the halo sign are most suggestive of fungal infection. Other high-resolution CT patterns are not helpful in distinguishing among the various types of infection seen in bone marrow transplant recipients.

Circulating KL-6 levels in patients with drug induced pneumonitis

BACKGROUND

The circulating level of KL-6/MUC1 is a sensitive marker for various interstitial lung diseases. Previous case reports have suggested that KL-6 may also be increased in some patients with drug induced pneumonitis. A study was undertaken to determine whether serum KL-6 could be a marker for particular types of drug induced pneumonitis.

METHODS

The findings of high resolution computed tomographic (HRCT) chest scans of 30 patients with drug induced pneumonitis were reviewed separately by two independent observers. The pneumonitis was classified into four predominant patterns: widespread bilateral consolidation (diffuse alveolar damage, DAD; n=7), fibrosis with or without consolidation (chronic interstitial pneumonia, CIP; n=11), consolidation without fibrosis (bronchiolitis obliterans organising pneumonia or eosinophilic pneumonia, BOOP/EP; n=8), and diffuse ground glass opacities without fibrosis (hypersensitivity pneumonitis, HP; n=4). Serum KL-6 levels were measured by a sandwich enzyme linked immunosorbent assay.

RESULTS

The overall sensitivity of serum KL-6 in detecting drug induced lung disease was 53.3%, which was lower than its sensitivity in detecting other interstitial lung diseases. However, the KL-6 level was increased in most patients with a DAD or CIP pattern (16/18; 88.9%) and was closely correlated with their clinical course. In contrast, serum KL-6 levels were within the normal range in all patients with a BOOP/EP or HP pattern.

CONCLUSIONS

Particular patterns detected by HRCT scanning, such as DAD and CIP but not the BOOP/EP or HP patterns, are associated with increased circulating KL-6 levels in drug induced pneumonitis. Serum KL-6 levels may reflect the clinical activity of the particular disorders.

Pulmonary infiltrates and fever in patients with hematologic malignancy: assessment of transbronchial biopsy

Pulmonary infiltrates associated with fever are frequently encountered in patients with acute leukemia or lymphoma; In this prospective series, we analyze 47 such episodes in 43 patients. Overall mortality was 45 per cent in patients with infiltrates and somewhat higher when they also had neutropenia (55 per cent) or acute leukemia (67 per cent). Pulmonary infiltrates could be categorized into three roentgenographic patterns: local consolidation (55 per cent); cavitary disease (13 per cent) and diffuse interstitial disease (32 percent). The exact etiology of the infiltrates could not be predicted by roentgenographic study. Microbiologic or histopathologic diagnosis was established during life in 57 per cent of the patients, with infection most commonly encountered. Twenty-one patients underwent lung biopsy procedures. Biopsy specimens were frequently diagnostic (n = 17) and often dictated therapeutic changes (n = 12). Transbronchial lung biopsy via the fiberoptic bronchoscope was utilized in 14 patients during the latter part of this study; diagnoses were obtained in nine patients. Morbidity was minimal with this procedure, and the need for thoracotomy was diminished when it was available.

High-resolution ultrafast chest CT in the clinical management of febrile bone marrow transplant patients with normal or nonspecific chest roentgenograms

Plain chest roentgenograms may be normal or show nonspecific abnormalities during the frequent febrile episodes that occur in patients after bone marrow transplantation. In this group, ultrafast 10-mm and 3-mm high-resolution CT scans were prospectively performed in 33 patients to determine if useful information was provided that either changed the patient's clinical management or added confidence to the clinical diagnosis. The 36 symptomatic episodes that occurred in 33 patients included fever in 20 episodes and fever combined with cough, dyspnea, chest pain, or rales in 16. Fourteen chest roentgenograms were interpreted as normal, and 22 were interpreted as demonstrating nonspecific changes; however, none of the roentgenograms was considered helpful in that they did not provide sufficient information for further management. In 2 of 14 episodes in patients with normal chest roentgenograms and in 9 of 22 episodes in patients with nonspecific chest roentgenograms, CT scanning resulted in a change in clinical management that included performing bronchoscopy, increasing or changing antibiotic coverage, starting white blood cell transfusions, requesting surgical biopsy, or a combination of these. In 1 of 14 episodes in patients with normal chest roentgenograms and in 8 of 22 episodes in patients with nonspecific roentgenograms, CT added confidence to the diagnosis. In the remaining 16 episodes, CT scans provided no additional information. We conclude that in many instances, noncontrast ultrafast chest CT scans can provide information that may either change a patient's clinical management or more clearly establish the extent of pulmonary disease.

Review on Diagnosis of COVID-19 from Chest CT Images Using Artificial Intelligence

The COVID-19 diagnostic approach is mainly divided into two broad categories, a laboratory-based and chest radiography approach. The last few months have witnessed a rapid increase in the number of studies use artificial intelligence (AI) techniques to diagnose COVID-19 with chest computed tomography (CT). In this study, we review the diagnosis of COVID-19 by using chest CT toward AI. We searched ArXiv, MedRxiv, and Google Scholar using the terms "deep learning", "neural networks", "COVID-19", and "chest CT". At the time of writing (August 24, 2020), there have been nearly 100 studies and 30 studies among them were selected for this review. We categorized the studies based on the classification tasks: COVID-19/normal, COVID-19/non-COVID-19, COVID-19/non-COVID-19 pneumonia, and severity. The sensitivity, specificity, precision, accuracy, area under the curve, and F1 score results were reported as high as 100%, 100%, 99.62, 99.87%, 100%, and 99.5%, respectively. However, the presented results should be carefully compared due to the different degrees of difficulty of different classification tasks.