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1.  Chest tube complications: How well are we training our residents? 
Canadian Journal of Surgery  2007;50(6):450-458.
Thoracic trauma is commonly treated with tube thoracostomy. The overall complication rate associated with this procedure is up to 30% among all operators. The primary purpose of this study was to define the incidence and risk factors for complications in chest tubes placed exclusively by resident physicians. The secondary objective was to outline the rate of complications occult to postinsertional supine anteroposterior (AP) chest radiographs (CXRs).
Over a 12-month period at a regional trauma centre, we retrospectively reviewed all severely injured trauma patients (injury severity score ≥ 12) who underwent tube thoracostomy (338/761 patients). Insertional, positional and infective complications were identified. Patients were assessed for complications on the basis of resident operator characteristics, patient demographics, associated injuries and outcomes. Thoracoabdominal CT scans and corresponding CXRs were also used to determine the rate of complications occult to postinsertional supine AP CXR.
Of the patients, 338 (44%,) had CXR and CT imaging. Out of 76 (22%) chest tubes placed by residents in 61 (18%) patients (99% of whom had blunt trauma injuries), there were 17 complications; 6 (35%) were insertional; 9 (53%) were positional and 2 (12%) were infective. Tube placement outside the trauma bay (p = 0.04) and nonsurgical resident operators (p = 0.03) were independently predictive of complications. The rates of complications according to training discipline were as follows: 7% general surgery, 13% internal and family medicine, 25% other surgical disciplines and 40% emergency medicine. Resident seniority, time of day and other factors were not predictive. Six of 11 (55%) positional and intraparenchymal lung tube placements were occult to postinsertional supine AP CXR.
Chest tubes placed by resident physicians are commonly associated with complications that are not identified by postinsertional AP CXR. Thoracic CT is the only way to reliably identify this morbidity. The differential rate of complications according to resident specialty suggests that residents in non–general surgical training programs may benefit from more structured instruction and closer supervision in tube thoracostomy.
PMCID: PMC2386217  PMID: 18053373
2.  The effect of a tuberculosis chest X-ray image reference set on non-expert reader performance 
European Radiology  2013;23(9):2459-2468.
In low-resource settings, limitations in diagnostic accuracy of chest X-rays (CXR) for pulmonary tuberculosis (PTB) relate partly to non-expert interpretation. We piloted a TB CXR Image Reference Set (TIRS) to improve non-expert performance in an operational setting in Malawi.
Nineteen doctors and clinical officers read 60 CXR of patients with suspected PTB, at baseline and using TIRS. Two officers also used the CXR Reading and Recording System (CRRS). Correct treatment decisions were assessed against a “gold standard” of mycobacterial culture and expert performance.
TIRS significantly increased overall non-expert sensitivity from 67.6 (SD 14.9) to 75.5 (SD 11.1, P = 0.013), approaching expert values of 84.2 (SD 5.2). Among doctors, correct decisions increased from 60.7 % (SD 7.9) to 67.1 % (SD 8.0, P = 0.054). Clinical officers increased in sensitivity from 68.0 % (SD 15) to 77.4 % (SD 10.7, P = 0.056), but decreased in specificity from 55.0 % (SD 23.9) to 40.8 % (SD 10.4, P = 0.049). Two officers made correct treatment decisions with TIRS in 62.7 %. CRRS training increased this to 67.8 %.
Use of a CXR image reference set increased correct decisions by doctors to treat PTB. This tool may provide a low-cost intervention improving non-expert performance, translating into improved clinical care. Further evaluation is warranted.
Key Points
• Tuberculosis treatment decisions are influenced by CXR findings, despite improved laboratory diagnostics.
• In low-resource settings, CXR interpretation is performed largely by non-experts.
• We piloted the effect of a simple reference training set of CXRs.
• Use of the reference set increased the number of correct treatment decisions. This effect was more marked for doctors than clinical officers.
• Further evaluation of this simple training tool is warranted.
Electronic supplementary material
The online version of this article (doi:10.1007/s00330-013-2840-z) contains supplementary material, which is available to authorized users.
PMCID: PMC3738845  PMID: 23652843
Radiography; Tuberculosis; Malawi; Sensitivity and Specificity; Teaching
3.  The role and performance of chest X-ray for the diagnosis of tuberculosis: A cost-effectiveness analysis in Nairobi, Kenya 
The objective of this study was to establish 1) the performance of chest X-ray (CXR) in all suspects of tuberculosis (TB), as well as smear-negative TB suspects and 2) to compare the cost-effectiveness of the routine diagnostic pathway using Ziehl-Neelsen (ZN) sputum microscopy followed by CXR if case of negative sputum result (ZN followed by CXR) with an alternative pathway using CXR as a screening tool (CXR followed by ZN).
From TB suspects attending a chest clinic in Nairobi, Kenya, three sputum specimens were examined for ZN and culture (Lowenstein Jensen). Culture was used as gold standard. From each suspect a CXR was made using a four point scoring system: i: no pathology, ii: pathology not consistent for TB, iii: pathology consistent for TB and iv: pathology highly consistent for TB. The combined score i + ii was labeled as "no TB" and the combined score iii + iv was labeled as "TB". Films were re-read by a reference radiologist. HIV test was performed on those who consented. Laboratory and CXR costs were used to compare for cost-effectiveness.
Of the 1,389 suspects enrolled, for 998 (72%) data on smear, culture and CXR was complete. 714 films were re-read, showing a 89% agreement (kappa value = 0.75 s.e.0.037) for the combined scores "TB" or "no-TB". The sensitivity/specificity of the CXR score "TB" among smear-negative suspects was 80%/67%. Using chest CXR as a screening tool in all suspects, sensitivity/specificity of the score "any pathology" was 92%, respectively 63%. The cost per correctly diagnosed case was for the routine process $8.72, compared to $9.27 using CXR as screening tool. When costs of treatment were included, CXR followed by ZN became more cost-effective.
The diagnostic pathway ZN followed by CXR was more cost-effective as compared to CXR followed by ZN. When cost of treatment was also considered CXR followed by ZN became more cost-effective. The low specificity of chest X-ray remains a subject of concern. Depending whether CXR was performed on all suspects or on smear-negative suspects only, 22%–45% of patients labeled as "TB" had a negative culture. The introduction of a well-defined scoring system, clinical conferences and a system of CXR quality control can contribute to improved diagnostic performance.
PMCID: PMC1326228  PMID: 16343340
4.  The clinical value of daily routine chest radiographs in a mixed medical–surgical intensive care unit is low 
Critical Care  2005;10(1):R11.
The clinical value of daily routine chest radiographs (CXRs) in critically ill patients is unknown. We conducted this study to evaluate how frequently unexpected predefined major abnormalities are identified with daily routine CXRs, and how often these findings lead to a change in care for intensive care unit (ICU) patients.
This was a prospective observational study conducted in a 28-bed, mixed medical–surgical ICU of a university hospital.
Over a 5-month period, 2,457 daily routine CXRs were done in 754 consecutive ICU patients. The majority of these CXRs did not reveal any new predefined major finding. In only 5.8% of daily routine CXRs (14.3% of patients) was one or more new and unexpected abnormality encountered, including large atelectases (24 times in 20 patients), large infiltrates (23 in 22), severe pulmonary congestion (29 in 25), severe pleural effusion (13 in 13), pneumothorax/pneumomediastinum (14 in 13), and malposition of the orotracheal tube (32 in 26). Fewer than half of the CXRs with a new and unexpected finding were ultimately clinically relevant; in only 2.2% of all daily routine CXRs (6.4% of patients) did these radiologic abnormalities result in a change to therapy. Subgroup analysis revealed no differences between medical and surgical patients with regard to the incidence of new and unexpected findings on daily routine CXRs and the effect of new and unexpected CXR findings on daily care.
In the ICU, daily routine CXRs seldom reveal unexpected, clinically relevant abnormalities, and they rarely prompt action. We propose that this diagnostic examination be abandoned in ICU patients.
PMCID: PMC1550788  PMID: 16420655
5.  Is a postintubation chest radiograph necessary in the emergency department? 
Postintubation chest X-rays (CXR) are standard practice in emergency department (ED) intubations. In the operating room, it is not usually a standard practice to confirm endotracheal tube placement with a CXR.
We seek to study the utility of postintubation CXR in ED patients.
This was a retrospective case series of 157 adult patients intubated in the ED of an urban academic hospital with an emergency medicine training program. Standardized chart review was performed by two emergency physicians (EP) using a structured data abstraction tool and final radiology attending reads of postintubation CXR to assess placement. Endotracheal tube placement was graded as satisfactory, too high, too low, or malpositioned in the esophagus. Descriptive statistics were used, and 95% confidence intervals (CI) were reported. Hospital Institutional Review Board approval was obtained.
A total of 157 patients were intubated in the ED during the study period: 127 (81%, 95% CI: 74–86) had adequate tube placement by CXR confirmation, 9 (6%, 95% CI: 3–11) endotracheal tubes were judged to be too high, and 20 (13%, 95% CI: 8–19) were judged to be too low with 10 (6.5%, 95% CI: 3–11) of these being right mainstem bronchus intubations. One patient (<1%, 95% CI:<0.0001–4) had a CXR confirming esophageal intubation.
ED intubations were judged to have “satisfactory” placement by CXR in 81% of patients. CXR is able to identify a small subset of patients that likely need immediate intervention based on their CXR. Until further studies refute the utility of postintubation CXR in ED intubations, they should remain a part of routine practice.
PMCID: PMC2840601  PMID: 20436895
Intubation; Chest X-ray; Emergency department
6.  Bone Suppression Increases the Visibility of Invasive Pulmonary Aspergillosis in Chest Radiographs 
PLoS ONE  2014;9(10):e108551.
Chest radiographs (CXR) are an important diagnostic tool for the detection of invasive pulmonary aspergillosis (IPA) in critically ill patients, but their diagnostic value is limited by a poor sensitivity. By using advanced image processing, the aim of this study was to increase the value of chest radiographs in the diagnostic work up of neutropenic patients who are suspected of IPA.
The frontal CXRs of 105 suspected cases of IPA were collected from four institutions. Radiographs could contain single or multiple sites of infection. CT was used as reference standard. Five radiologists and two residents participated in an observer study for the detection of IPA on CXRs with and without bone suppressed images (ClearRead BSI 3.2; Riverain Technologies). The evaluation was performed separately for the right and left lung, resulting in 78 diseased cases (or lungs) and 132 normal cases (or lungs). For each image, observers scored the likelihood of focal infectious lesions being present on a continuous scale (0–100). The area under the receiver operating characteristics curve (AUC) served as the performance measure. Sensitivity and specificity were calculated by considering only the lungs with a suspiciousness score of greater than 50 to be positive.
The average AUC for only CXRs was 0.815. Performance significantly increased, to 0.853, when evaluation was aided with BSI (p = 0.01). Sensitivity increased from 49% to 66% with BSI, while specificity decreased from 95% to 90%.
The detection of IPA in CXRs can be improved when their evaluation is aided by bone suppressed images. BSI improved the sensitivity of the CXR examination, outweighing a small loss in specificity.
PMCID: PMC4184785  PMID: 25279774
7.  Predictors of pulmonary involvement in patients with extra-pulmonary tuberculosis 
The aim of this study is to assess the value of chest radiographs (CXRs) and sputum examinations in detecting pulmonary involvement of tuberculosis (TB) in patients with extra-pulmonary tuberculosis (EPTB).
Materials and Methods:
A retrospective analysis was performed among 248 EPTB patients with culture-proven diagnosis of tuberculosis seen between January 2001 and December 2007 at a tertiary teaching hospital, Riyadh, Saudi Arabia. Demographics, clinical, laboratory and radiological findings were reviewed and assessed. This study was approved by the hospital ethics and research committee.
One hundred twenty five of 233 EPTB patients (53.6%) had abnormal CXR findings. There was a significant difference in the occurrence of positive sputum culture results between patients with abnormal CXR findings (30/57) and those with normal CXR findings (4/17) (P = 0.04). Of 17 HIV-negative/unknown HIV-status EPTB patients with normal CXR results, 4 patients (23.5%) had positive sputum culture results. Intrathoracic lymphadenopathy (P < 0.001), pleural TB (P < 0. 001) and disseminated TB (P = 0.004) were associated with an increased risk of abnormal CXR findings. Patients with cough (52.9%), weight loss (41.2%) and night sweats (26.5%) are more likely to have positive sputum culture results.
CXR findings are predictive of positive sputum culture results. However, the rate of normal CXR among EPTB patients with positive sputum culture results was relatively high. Therefore, respiratory specimen cultures should be obtained in TB suspects with a normal CXR to identify potentially infectious cases of TB.
PMCID: PMC3410185  PMID: 22870411
Predictors; pulmonary; extra-pulmonary tuberculosis; radiology
8.  A recommended method in order to interpret chest x-rays for diagnosing small size pneumothorax 
Pneumothorax can be a both progressive and life threatening disorder. In this survey we evaluated the diagnostic accuracy of a recommended method for the interpretation of chest X-Rays (CXRs) compared to the common method in diagnosis of iatrogenic Pneumothorax in an emergency department.
Materials and Methods:
We conducted a study on 100 CXRs (31 with the diagnosis of small size pneumothorax and 69 normal) of patients who have undergone the upper central venous catheterization. CXRs were interpreted by 5 Emergency Specialists (ESs) and 5 general practitioners (GPs) separately using the conventional and recommended method. Recommended method included a 90 degree rotation against the side of chateterization in addition to using a yellow shield as the background color. Presence of pneumothorax on the CXR was confirmed by a radiologist.
64.5% of the CXRs with pneumothorax were correctly diagnosed by GPs and 87.7% by ESs with reutine method and 83.2% and 97.4% by recommended method, respectively (P.value<0.001). 96.8% out of all CXRs were correctly diagnosed by GPs and 99.4% by ESs by conventional method and 97.9% by GP and 99.7% by ES was correctly diagnosed using recommended method(P.value<0.001). None of the underlying variables including sex, age, underlying diseases, the side of intervention did not affect on the diagnostic accuracy in either groups (P.value>0.05).
A significant raise was obtained in the diagnostic accuracy of CXR using the recommended method. This study can be a preliminary study to conduct further investigations in order to enhance the diagnostic accuracy of CXRs.
PMCID: PMC3665117  PMID: 23724383
Central venous catheterization; chest x-ray; diagnostic accuracy; iatrogenic pneumothorax; interpretation
9.  A population-based cohort study of chest x-ray screening in smokers: lung cancer detection findings and follow-up 
BMC Cancer  2012;12:18.
Case-control studies of mass screening for lung cancer (LC) by chest x-rays (CXR) performed in the 1990s in scarcely defined Japanese target populations indicated significant mortality reductions, but these results are yet to be confirmed in western countries. To ascertain whether CXR screening decreases LC mortality at community level, we studied a clearly defined population-based cohort of smokers invited to screening. We present here the LC detection results and the 10-year survival rates.
The cohort of all smokers of > 10 pack-years resident in 50 communities of Varese, screening-eligible (n = 5,815), in July 1997 was invited to nonrandomized CXR screening. Self-selected participants (21% of cohort) underwent screening in addition to usual care; nonparticipants received usual care. The cohort was followed-up until December 2010. Kaplan-Meier LC-specific survival was estimated in participants, in nonparticipants, in the whole cohort, and in an uninvited, unscreened population (control group).
Over the initial 9.5 years of study, 67 LCs were diagnosed in screening participants (51% were screen-detected) and 178 in nonparticipants. The rates of stage I LC, resectability and 5-year survival were nearly twice as high in participants (32% stage I; 48% resected; 30.5% 5-year survival) as in nonparticipants (17% stage I; 27% resected; 13.5% 5-year survival). There were no bronchioloalveolar carcinomas among screen-detected cancers, and median volume doubling time of incidence screen-detected LCs was 80 days (range, 44-318), suggesting that screening overdiagnosis was minimal. The 10-year LC-specific survival was greater in screening participants than in nonparticipants (log-rank, p = 0.005), and greater in the whole cohort invited to screening than in the control group (log-rank, p = 0.001). This favourable long-term effect was independently related to CXR screening exposure.
In the setting of CXR screening offered to a population-based cohort of smokers, screening participants who were diagnosed with LC had more frequently early-stage resectable disease and significantly enhanced long-term LC survival. These results translated into enhanced 10-year LC survival, independently related to CXR screening exposure, in the entire population-based cohort. Whether increased long-term LC-specific survival in the cohort corresponds to mortality reduction remains to be evaluated.
Trial registration number
PMCID: PMC3315414  PMID: 22251777
Lung cancer; Chest x-ray screening; Population-based; Cohort study; volunteer effect; Survival; Community
10.  Association of Lung Function, Chest Radiographs and Clinical Features in Infants with Cystic Fibrosis 
The European respiratory journal  2013;42(6):10.1183/09031936.00138412.
The optimal strategy for monitoring cystic fibrosis (CF) lung disease in infancy remains unclear.
To describe longitudinal associations between infant pulmonary function tests (iPFTs), chest radiograph (CXR) scores and other characteristics.
CF patients ≤ 24 months old were enrolled in a 10-center study evaluating iPFTs 4 times over a year. CXRs ~1 year apart were scored with the Wisconsin and Brasfield systems. Associations of iPFT parameters with clinical characteristics were evaluated with mixed effects models.
The 100 participants contributed 246 acceptable flow/volume (FEV0.5, FEF75) and 303 acceptable functional residual capacity (FRC) measurements and 171 CXRs. Both Brasfield and Wisconsin CXR scores worsened significantly over the 1 year interval. Worse Wisconsin CXR scores and S. aureus were both associated with hyperinflation (significantly increased FRC) but not with diminished FEV0.5 or FEF75. Parent-reported cough was associated with significantly diminished FEF75 but not with hyperinflation.
In this infant cohort in whom we previously reported worsening in average lung function, CXR scores also worsened over a year. The significant associations detected between both Wisconsin CXR score and S. aureus and hyperinflation, as well as between cough and diminished flows, reinforce the ability of iPFTs and CXRs to detect early CF lung disease.
PMCID: PMC3795977  PMID: 23722613
cystic fibrosis; imaging; infants; lung function
11.  Is routine chest radiography indicated following chest drain removal after cardiothoracic surgery? 
A best evidence topic was written according to a structured protocol. The question addressed was whether routine chest radiography is indicated following chest drain removal in patients undergoing cardiothoracic surgery. A total of 356 papers were found using the reported searches; of which, 6 represented the best evidence to answer the clinical question. The authors, date, journal, study type, population, main outcome measures and results are tabulated. Reported measures were mean duration of drains left in situ, timing of drain removal, pathology detected on chest radiographs (CXRs), interventions following imaging and clinical assessment, complications in patients not undergoing routine CXRs and the cost saving of omitting routine CXRs. One large cohort study reported the detection of pathology in 79% of clinically indicated CXRs in comparison to 40% of routine CXRs (P = 0.005). Ninety-five per cent of the non-routine CXR cohort remained asymptomatic and required no intervention. One large observational study reported the detection of new pneumothoraces in 9.3% of patients, 70.3% of which were barely perceptible. Intervention following CXR was required in 0.25% and only one medium-sized pneumothorax would have been potentially missed without CXR. Another large observational study reported intervention following CXR in 1.9% and the presence of relevant clinical signs and symptoms to be a significant predictor of major intervention (P < 0.01). A smaller observational study reported no pathology detected or intervention following CXR in 98% and the cost saving of omitting a single CXR at £10 000 per annum. Another small observational study reported only 7% of CXRs to be clinically indicated with a false-positive rate of 100%, and a false-negative rate of 7% in CXRs not clinically indicated. The smallest study reported no complications in the non-CXR cohort and only one patient undergoing intervention in the routine CXR cohort. We conclude that there is evidence that routine post drain removal CXR provides no diagnostic or therapeutic advantage over clinically indicated CXR or simple clinical assessment. The best evidence studies reported the detection of pathology on routine CXR ranging from 2 to 40% compared with 79% in clinically indicated CXRs (P = 0.005). Whilst the rate of intervention following routine CXR was as high as 4% in the smallest study, clinical signs and symptoms suggestive of pathology were a significant predictor of major re-intervention (P < 0.01).
PMCID: PMC3352714  PMID: 22392935
Chest drain; Chest radiography
12.  Pulmonary staging in colorectal cancer--is computerised tomography the answer? 
INTRODUCTION: Pulmonary staging in colorectal cancer (CRC) has traditionally been carried out by means of plain chest radiograph (CXR), although computerised tomography (CT) imaging of the chest is increasingly being performed for this purpose. The aim of this study was to assess the value of pre-operative thoracic CT for pulmonary staging in CRC. PATIENTS AND METHODS: Data were collected prospectively on all patients referred into hospital over a 20-month study period for double contrast barium enema evaluation of symptoms suggestive of an underlying CRC. Patients with a CRC went on to have a staging intravenous, contrast-enhanced CT of the chest, abdomen and pelvis prior to an out-patient appointment with a colorectal surgeon. The CXRs of those patients in whom a radiological abnormality was seen on thoracic CT were reviewed blindly by an independent consultant radiologist. RESULTS: A total of 403 barium enemas were performed, of which 38 demonstrated a CRC (9%). In those patients diagnosed with CRC, nine (24%) had an abnormality on thoracic CT. Four patients with positive thoracic CTs had chemotherapy and or radiotherapy with no surgery. One patient underwent colectomy, and 2 patients who had primary lung tumours as opposed to metastases also underwent colectomies. One patient received palliative care only. In addition, one of the patients underwent multiple, non-diagnostic thoracic investigations prior to a diagnosis of sarcoidosis being made and then proceeding to surgery. An independent consultant radiologist reviewed seven out of the nine CXRs of patients with an abnormality on thoracic CT without knowledge of the clinical diagnosis, and reported three of the CXRs to be normal. CONCLUSIONS: Thoracic CT appears to improve the accuracy of pulmonary staging in CRC allowing a more appropriate level of intervention. However, CT is likely to identify more benign radiological abnormalities than CXR alone, and investigations should not occur to the detriment of treating the primary tumour.
PMCID: PMC1963965  PMID: 16176690
13.  The intrapleural volume threshold for ultrasound detection of pneumothoraces: An experimental study on porcine models 
Small pneumothoraxes (PTXs) may not impart an immediate threat to trauma patients after chest injuries. However, the amount of pleural air may increase and become a concern for patients who require positive pressure ventilation or air ambulance transport. Lung ultrasonography (US) is a reliable tool in finding intrapleural air, but the performance characteristics regarding the detection of small PTXs need to be defined. The study aimed to define the volume threshold of intrapleural air when PTXs are accurately diagnosed with US and compare this volume with that for chest x-ray (CXR).
Air was insufflated into a unilateral pleural catheter in seven incremental steps (10, 25, 50, 100, 200, 350 and 500 mL) in 20 intubated porcine models, followed by a diagnostic evaluation with US and a supine anteroposterior CXR. The sonographers continued the US scanning until the PTXs could be ruled in, based on the pathognomonic US “lung point” sign. The corresponding threshold volume was noted. A senior radiologist interpreted the CXR images.
The mean threshold volume to confirm the diagnosis of PTX using US was 18 mL (standard deviation of 13 mL). Sixty-five percent of the PTXs were already diagnosed at 10 mL of intrapleural air; 25%, at 25 mL; and the last 10%, at 50 mL. At an air volume of 50 mL, the radiologist only identified four out of 20 PTXs in the CXR pictures; i.e., a sensitivity of 20% (95% CI: 7%, 44%). The sensitivity of CXR increased as a function of volume but leveled off at 67%, leaving one-third (1/3) of the PTXs unidentified after 500 mL of insufflated air.
Lung US is very accurate in diagnosing even small amounts of intrapleural air and should be performed by clinicians treating chest trauma patients when PTX is among the differential diagnoses.
PMCID: PMC3602194  PMID: 23453044
(MeSH terms): Pneumothorax; Ultrasonography; Chest x-ray; Computed tomography; Pleura and (models animal)
14.  Clinical significance of normal chest radiographs among HIV-seropositive patients with suspected tuberculosis in Uganda 
Respirology (Carlton, Vic.)  2011;16(5):836-841.
Background and objectives
The frequency, aetiologies, and outcomes of normal chest radiographs (CXRs) among HIV-seropositive patients with suspected pulmonary tuberculosis (TB) have been infrequently described.
Consecutive HIV-seropositive adults hospitalized for cough of ≥ 2 weeks duration at Mulago Hospital (Kampala, Uganda), between September 2007 and July 2008, were enrolled. Baseline CXRs were obtained on admission. Patients with sputum smears that were negative for acid-fast bacilli (AFB) were referred for bronchoscopy with bronchoalveolar lavage (BAL). BAL fluid was examined for mycobacteria, Pneumocystis jirovecii, and other fungi. Patients were followed for two months after enrolment.
Of the 334 patients, 54 (16%) had normal CXRs. These patients were younger (median age 30 vs. 34 years, P=0.002), had lower counts of CD4+ T lymphocytes (median 13 vs. 57 cells/μL, P<0.001), and were less likely to be smear positive for AFB (17% vs. 39%, P=0.002) than those with abnormal CXRs. Pulmonary TB was the most frequent diagnosis (44%) among those with normal CXRs, followed by unknown diagnoses, pulmonary aspergillosis, and pulmonary cryptococcosis. The frequency of normal CXRs was 12% among pulmonary TB patients. There was a trend towards increased two-month mortality among patients with normal CXRs compared to those with abnormal CXRs (40% vs. 29%, P=0.15).
Normal CXR findings were common among HIV-seropositive patients with suspected TB, especially those who were young, those with low CD4+ T cell counts, and those with sputum smears that were negative for AFB. Mortality was high among those with normal CXRs. Normal CXR findings should not preclude further diagnostic evaluation in this population.
PMCID: PMC3126910  PMID: 21518124
clinical epidemiology; critical care medicine; immunodeficiency; radiology and other imaging; tuberculosis
15.  Improving diagnostic accuracy in assessing pulmonary edema on bedside chest radiographs using a standardized scoring approach 
BMC Anesthesiology  2014;14(1):94.
To assess the value of a score-based system which allows standardized evaluation of pulmonary edema on bedside chest radiographs (CXRs) under routine clinical conditions.
Seven experienced readers assessed bedside CXRs of ten patients with an extravascular lung water (EVLW)-value of ≤ 8 mL/kg (range: 4–8 mL/kg; indicates no pulmonary edema) and a series of ten patients with an EVLW-value of ≥ 15 mL/kg (range: 15–21 mL/kg; = indicates a pulmonary edema) with and without customized software which would permit a standardized assessment of the various indications of pulmonary edema. The software provides a score that identifies patients with and without pulmonary edema. EVLW-values were measured instantly after bedside CXR imaging using a pulse contour cardiac output (PiCCO) system and served as a reference standard. The patients were non-traumatic and not treated with diuretics or dobutamine during bedside CXR imaging and the PiCCO measurements. Mean sensitivity, specificity, positive and negative predictive value, the percentage of overall agreement and the free-marginal multirater kappa value was calculated for both the standard and the standardized score-based approach. The net reclassification index was calculated for each reader as well as for all readers.
Evaluation of bedside CXRs by means of the score-based approach took longer (23 ± 12 seconds versus 7 ± 3 seconds without the use of the software) but improved radiologists’ sensitivity (from 57 to 77%), specificity (from 90 to 100%) and the free-marginal multirater kappa value (from 0.34 to 0.68). The positive predictive value was raised from 85 to 100% and the negative predictive value from 68 to 81%. A net reclassification index of 0.3 (all readers) demonstrates an improvement in prediction performance gained by the score-based approach. The percentage of overall agreement was 67% with the standard approach and 84% with the software-based approach.
The diagnostic accuracy of bedside CXRs to discriminate patients with elevated EVLW-values from those with a normal value can be improved with the use of a standardized score-based approach. The investigated system is freely available as a web-based application (accessible via:
PMCID: PMC4216356  PMID: 25364301
Bedside chest radiograph; Pulmonary edema; Scoring system; Extravascular lung water (EVLW); Web-based application
16.  Chest radiographic findings of pulmonary tuberculosis in severely immunocompromised patients with the human immunodeficiency virus 
The British Journal of Radiology  2012;85(1014):e130-e139.
We describe chest radiograph (CXR) findings in a population with a high prevalence of human immunodeficiency virus (HIV) and tuberculosis (TB) in order to identify radiological features associated with TB; to compare CXR features between HIV-seronegative and HIV-seropositive patients with TB; and to correlate CXR findings with CD4 T-cell count.
Consecutive adult patients admitted to a national referral hospital with a cough of duration of 2 weeks or longer underwent diagnostic evaluation for TB and other pneumonias, including sputum examination and mycobacterial culture, bronchoscopy and CXR. Two radiologists blindly reviewed CXRs using a standardised interpretation form.
Smear or culture-positive TB was diagnosed in 214 of 403 (53%) patients. Median CD4+ T-cell count was 50 cells mm–3 [interquartile range (IQR) 14–150]. TB patients were less likely than non-TB patients to have a normal CXR (12% vs 20%, p=0.04), and more likely than non-TB patients to have a diffuse pattern of opacities (75% vs 60%, p=0.003), reticulonodular opacities (45% vs 12%, p<0.001), nodules (14% vs 6%, p=0.008) or cavities (18% vs 7%, p=0.001). HIV-seronegative TB patients more often had consolidation (70% vs 42%, p=0.007) and cavities (48% vs 13%, p<0.001) than HIV-seropositive TB patients. TB patients with a CD4+ T-cell count of ≤50 cells mm–3 less often had consolidation (33% vs 54%, p=0.006) and more often had hilar lymphadenopathy (30% vs 16%, p=0.03) compared with patients with CD4 51–200 cells mm–3.
Although different CXR patterns can be seen in TB and non-TB pneumonias there is considerable overlap in features, especially among HIV-seropositive and severely immunosuppressed patients. Providing clinical and immunological information to the radiologist might improve the accuracy of radiographic diagnosis of TB.
PMCID: PMC3474111  PMID: 21976629
17.  High Discordance of Chest X-ray and CT for Detection of Pulmonary Opacities in ED Patients: Implications for Diagnosing Pneumonia 
To evaluate the diagnostic performance of chest x-ray (CXR) compared to computed tomography (CT) for detection of pulmonary opacities in adult emergency department (ED) patients.
We conducted an observational cross sectional study of adult patients presenting to 12 EDs in the United States from July 1, 2003 through November 30, 2006 who underwent both CXR and chest CT for routine clinical care. CXRs and CT scans performed on the same patient were matched. CXRs and CT scans were interpreted by attending radiologists and classified as containing pulmonary opacities if the final radiologist report noted opacity, infiltrate, consolidation, pneumonia, or bronchopneumonia. Using CT as a criterion standard, the diagnostic test characteristics of CXR to detect pulmonary opacities were calculated.
The study cohort included 3,423 patients. Shortness of breath, chest pain and cough were the most common complaints, with 96.1% of subjects reporting at least one of these symptoms. Pulmonary opacities were visualized on 309 (9.0%) CXRs and 191 (5.6 %) CT scans. CXR test characteristics for detection of pulmonary opacities included: sensitivity 43.5% (95% CI: 36.4%–50.8%); specificity 93.0% (95% CI: 92.1%–93.9%); positive predictive value 26.9% (95% CI: 22.1%–32.2%); and negative predictive value 96.5% (95% CI: 95.8%–97.1%).
In this multicenter cohort of adult ED patients with acute cardiopulmonary symptoms, CXR demonstrated poor sensitivity and positive predictive value for detecting pulmonary opacities. Reliance on CXR to identify pneumonia may lead to significant rates of misdiagnosis.
PMCID: PMC3556231  PMID: 23083885
chest x-ray; computed tomography; pneumonia; emergency department; diagnostic testing
18.  Role of Gist and PHOG Features in Computer-Aided Diagnosis of Tuberculosis without Segmentation 
PLoS ONE  2014;9(11):e112980.
Effective diagnosis of tuberculosis (TB) relies on accurate interpretation of radiological patterns found in a chest radiograph (CXR). Lack of skilled radiologists and other resources, especially in developing countries, hinders its efficient diagnosis. Computer-aided diagnosis (CAD) methods provide second opinion to the radiologists for their findings and thereby assist in better diagnosis of cancer and other diseases including TB. However, existing CAD methods for TB are based on the extraction of textural features from manually or semi-automatically segmented CXRs. These methods are prone to errors and cannot be implemented in X-ray machines for automated classification.
Gabor, Gist, histogram of oriented gradients (HOG), and pyramid histogram of oriented gradients (PHOG) features extracted from the whole image can be implemented into existing X-ray machines to discriminate between TB and non-TB CXRs in an automated manner. Localized features were extracted for the above methods using various parameters, such as frequency range, blocks and region of interest. The performance of these features was evaluated against textural features. Two digital CXR image datasets (8-bit DA and 14-bit DB) were used for evaluating the performance of these features.
Gist (accuracy 94.2% for DA, 86.0% for DB) and PHOG (accuracy 92.3% for DA, 92.0% for DB) features provided better results for both the datasets. These features were implemented to develop a MATLAB toolbox, TB-Xpredict, which is freely available for academic use at This toolbox provides both automated training and prediction modules and does not require expertise in image processing for operation.
Since the features used in TB-Xpredict do not require segmentation, the toolbox can easily be implemented in X-ray machines. This toolbox can effectively be used for the mass screening of TB in high-burden areas with improved efficiency.
PMCID: PMC4229306  PMID: 25390291
19.  Comparison of thermodilution measured extravascular lung water with chest radiographic assessment of pulmonary oedema in patients with acute lung injury 
Acute lung injury and the acute respiratory distress syndrome (ALI/ARDS) are characterized by pulmonary oedema, measured as extravascular lung water (EVLW). The chest radiograph (CXR) can potentially estimate the quantity of lung oedema while the transpulmonary thermodilution method measures the amount of EVLW. This study was designed to determine whether EVLW as estimated by a CXR score predicts EVLW measured by the thermodilution method and whether changes in EVLW by either approach predict mortality in ALI/ARDS.
Clinical data were collected within 48 hours of ALI/ARDS diagnosis and daily up to 14 days on 59 patients with ALI/ARDS. Two clinicians scored each CXR for the degree of pulmonary oedema, using a validated method. EVLW indexed to body weight was measured using the single indicator transpulmonary thermodilution technique.
The CXR score had a modest, positive correlation with the EVLWI measurements (r = 0.35, p < 0.001). There was a 1.6 ml/kg increase in EVLWI per 10-point increase in the CXR score (p < 0.001, 95% confidence interval 0.92-2.35). The sensitivity of a high CXR score for predicting a high EVLWI was 93%; similarly the negative predictive value was high at 94%; the specificity (51%) and positive predictive value (50%) were lower. The CXR scores did not predict mortality but the EVLW thermodilution did predict mortality.
EVLW measured by CXR was modestly correlated with thermodilution measured EVLW. Unlike CXR findings, transpulmonary thermodilution EVLWI measurements over time predicted mortality in patients with ALI/ARDS.
PMCID: PMC3846630  PMID: 23937970
Extravascular lung water; Chest radiograph; Acute lung injury; Acute respiratory distress syndrome
Journal of thoracic imaging  2012;27(4):249-254.
To measure reader variability related to the evaluation of screening chest radiographs (CXRs) for findings of primary lung cancer.
Materials and Methods
From the National Lung Screening Trial (NLST), 100 cases were randomly selected from baseline CXR examinations for retrospective interpretation by nine NLST radiologists; images with non calcified lung nodules (NCN) or other abnormalities suspicious for lung cancer as determined by the original NLST reader were over-sampled. Agreement on the presence of pulmonary nodules and abnormalities suspicious for cancer and recommendations for follow-up were assessed by the multirater Kappa statistic.
The multi-rater Kappa statistic for inter-reader agreement on the presence of at least one NCN was 0.38. Rates at which readers reported the presence of at least one NCN ranged from 32 to 63% (mean 41%); among 16 subjects with NCN and cancer diagnosis within one year of the CXR examination, a mean of 87% (range 81–94%) of cases were classified as suspicious for cancer across all readers. The multi-rater Kappa for agreement on follow-up recommendations was 0.34; pair wise Kappa values ranged from 0.15 to 0.64 (mean 0.36). For all subjects, readers recommended a follow-up procedure classified as high level (CT, FDG-PET, or biopsy) 42% of the time on average (range 30–67%); this increased to 84% (range 52–100%) when readers reported a NCN and 88% (range 82–94%) for subjects with cancer.
Reader agreement for screening CXR interpretation and follow-up recommendations is fair overall, but high for malignant lesions.
PMCID: PMC3409316  PMID: 22627615
Lung cancer; chest radiograph; reader variability; screening
21.  The Risk of Obstructive Lung Disease by Previous Pulmonary Tuberculosis in a Country with Intermediate Burden of Tuberculosis 
Journal of Korean Medical Science  2011;26(2):268-273.
We evaluated the effects of previous pulmonary tuberculosis (TB) on the risk of obstructive lung disease. We analyzed population-based, the Second Korea National Health and Nutrition Examination Survey 2001. Participants underwent chest X-rays (CXR) and spirometry, and qualified radiologists interpreted the presence of TB lesion independently. A total of 3,687 underwent acceptable spirometry and CXR. Two hundreds and ninty four subjects had evidence of previous TB on CXR with no subjects having evidence of active disease. Evidence of previous TB on CXR were independently associated with airflow obstruction (adjusted odds ratios [OR] = 2.56 [95% CI 1.84-3.56]) after adjustment for sex, age and smoking history. Previous TB was still a risk factor (adjusted OR = 3.13 [95% CI 1.86-5.29]) with exclusion of ever smokers or subjects with advanced lesion on CXR. Among never-smokers, the proportion of subjects with previous TB on CXR increased as obstructive lung disease became more severe. Previous TB is an independent risk factor for obstructive lung disease, even if the lesion is minimal and TB can be an important cause of obstructive lung disease in never-smokers. Effort on prevention and control of TB is crucial in reduction of obstructive lung disease, especially in countries with more than intermediate burden of TB.
PMCID: PMC3031013  PMID: 21286020
Tuberculosis; Lung Diseases, Obstructive
22.  Performance of Clinical Algorithms for Smear-Negative Tuberculosis in HIV-Infected Persons in Ho Chi Minh City, Vietnam 
Background. Tuberculosis (TB) disease diagnosis in Vietnam relies on symptom screening, chest radiography (CXR), and acid fast bacilli (AFB) sputum smear which have a poor sensitivity in HIV patients. We evaluated the performance of clinical algorithms in screening and diagnosing AFB smear-negative TB in HIV patients. Methods. We enrolled 399 HIV-positive patients seeking care at a HIV clinic in Ho Chi Minh City (HCMC), Vietnam. Participants' demographics, medical history, common TB symptoms, CXR, and laboratory tests were collected. Results. Of 399 HIV patients, 390 had initial AFB-negative smears and 22/390 patients had positive cultures. Symptom screening missed 54% (12/22) of smear-negative pulmonary TB (PTB) cases. Multivariate analysis found CD4+ cell level and CXR were significant PTB predictors. An algorithm combining four TB symptoms and TST presented a high sensitivity (100%), but poorly specific (24%) diagnostic performance for smear-negative PTB. Conclusion. Up to 54% of PTB cases in the HIV-infected population may be missed in the routine screening and diagnostic procedures used in Vietnam. Symptom screening was a poor overall diagnostic measure in detecting smear-negative TB in HIV patients. Our study results suggest that routine sputum cultures should be implemented to achieve a more accurate diagnosis of TB in HIV patients.
PMCID: PMC3512270  PMID: 23227329
23.  A Porcine Pneumothorax Model for Teaching Ultrasound Diagnostics 
Academic Emergency Medicine  2012;19(5):586-592.
Objectives: Ultrasound (US) is a sensitive diagnostic tool for detecting pneumothorax (PTX), but methods are needed to optimally teach this technique outside of direct patient care. In training and research settings, porcine PTX models are sometimes used, but the description of the PTX topography in these models is lacking. The study purpose was to define the distribution of air using the reference imaging standard computed tomography (CT), to see if pleural insufflation of air into a live anaesthetized pig truly imitates a PTX in an injured patient.
Methods: A unilateral catheter was inserted into one pleural cavity of each of 20 pigs, and 500 mL of air was insufflated. After a complete thoracic CT scan, the anterior, lateral, medial, basal, apical, and posterior components of the PTXs were compared. The amount of air in each location was quantified by measuring the distance from the lung edge to the chest wall (LE-CW). A supine anteroposterior chest radiograph (CXR) was taken from each model and interpreted by a senior radiologist, and the image results were compared to CT.
Results: All 20 hemithoraces with PTX were correctly identified by CT, while six remained occult after interpreting the CXRs. The PTXs were anterior (100%), lateral (95%), medial (80%), basal (60%), apical (45%), and posterior (15%). The major proportion of the insufflated 500-mL volume was found in the anterior, medial, and basal recesses.
Conclusions: The authors found the distribution of the intrathoracic air to be similar between a porcine model and that to be expected in human trauma patients, all having predominantly anterior PTX topographies. In a training facility, the model is easy to set up and can be scanned by the participants multiple times. To acquire the necessary skills to perform thoracic US examinations for PTX, the porcine models could be useful.
PMCID: PMC3502747  PMID: 22594363
24.  Descriptive analysis of the respiratory health status of persons exposed to Libby amphibole asbestos 
BMJ Open  2012;2(6):e001552.
Describe respiratory health and quality of life in persons exposed to Libby amphibole asbestos (LAA) contaminated vermiculite.
Cross-sectional descriptive.
Asbestos-related disease clinic in Libby, Montana USA.
329 individuals exposed to LAA; mostly men, married, between 50 and 69 years; two-thirds lived in the surrounding county; one-third lived elsewhere in the state and USA.
Primary outcome measures
Chest radiograph (CXR), pulmonary function data and the St George Respiratory Questionnaire (SGRQ).
Exposure categories included vermiculite workers=7.6%; family/household contact of vermiculite worker=32%; and environmental exposure only=60%. Of the participants, 55% had only pleural abnormalities; 5.4% had only interstitial abnormalities; nearly 21% had both abnormalities and 18% had no lung abnormality on chest x-ray. Mean forced vital capacity (FVC) 95.3% (SD=18.7); forced expiratory volume (FEV1) mean 87% (SD=20.2); ratio of FEV11/FVC 95.5% (SD=12.0); and diffusing capacity (DLCO) of 83% (SD=21.7) of the percent predicted. The mean total SGRQ (38.5; SD=22.1) indicated a lower quality of life than healthy persons and persons with other chronic conditions. SGRQ subscale means were Symptoms 52.1 (SD=24.9), activity 49.4 (SD=26.9) and impacts 27.5 (SD=21.9). Participants with normal CXR differed significantly from those with both interstitial and pleural abnormalities on total, activity and impacts scores. For activity alone, subjects with normal CXR differed significantly from those with pleural disease; no differences were found for those with interstitial disease. Significant findings were found for smoking history across all pulmonary measures, and for exposure status, radiographic findings, age and gender for select pulmonary parameters. Subjects with any smoking history had significantly worse average total and subscale scores on the SGRQ.
Of 329 persons exposed to LAA, the majority (182) had pleural abnormalities identified on CXR. SGRQ scores for persons with abnormalities (pleural, interstitial or both) (269) differed significantly from those with a normal CXR.
PMCID: PMC3532993  PMID: 23175736
Public Health; Occupational & Industrial Medicine; Internal Medicine
25.  Significant changes in the practice of chest radiography in Dutch intensive care units: a web-based survey 
ICU patients frequently undergo chest radiographs (CXRs). The diagnostic and therapeutic efficacy of routine CXRs are now known to be low, but the discussion regarding specific indications for CXRs in critically ill patients and the safety of abandoning routine CXRs is still ongoing. We performed a survey of Dutch intensivists on the current practice of chest radiography in their departments.
Web-based questionnaires, containing questions regarding ICU characteristics, ICU patients, daily CXR strategies, indications for routine CXRs and the practice of radiologic evaluation, were sent to the medical directors of all adult ICUs in the Netherlands. CXR strategies were compared between all academic and non-academic hospitals and between ICUs of different sizes. A comparison was made between the survey results obtained in 2006 and 2013.
Of the 83 ICUs that were contacted, 69 (83%) responded to the survey. Only 7% of responding ICUs were currently performing daily routine CXRs for all patients, and 61% of the responding ICUs were said never to perform CXRs on a routine basis. A daily meeting with a radiologist is an established practice in 72% of the responding ICUs and is judged to be important or even essential by those ICUs. The therapeutic efficacy of routine CXRs was assumed by intensivists to be lower than 10% or to be between 10 and 20%. The efficacy of ‘on-demand’ CXRs was assumed to be between 10 and 60%. There is a consensus between intensivists to perform a routine CXR after endotracheal intubation, chest tube placement or central venous catheterization.
The strategy of daily routine CXRs for critically ill and mechanically ventilated patients has turned from being a common practice in 2006 to a rare current practice. Other routine strategies and an ‘on-demand only’ strategy have become more popular. Intensivists still assume the value of CXRs to be higher than the efficacy that is reported in the literature.
PMCID: PMC4113284  PMID: 24708581
Chest radiography; Imaging; Intensive care

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