High resolution computed tomographic findings in pulmonary tuberculosis

Radiomics analysis of lung CT for multidrug resistance prediction in active tuberculosis: a multicentre study

OBJECTIVES

Multidrug-resistant TB (MDR-TB) is a severe burden and public health threat worldwide. This study aimed to develop a radiomics model based on the tree-in-bud (TIB) sign and nodules and validate its predictive performance for MDR-TB.

METHODS

We retrospectively recruited 454 patients with proven active TB from two hospitals and classified them into three training and testing cohorts: TIB (n = 295, 102), nodules (n = 302, 97), and their combination (n = 261, 81). Radiomics features relating to TIB and nodules were separately extracted. The maximal information coefficient and recursive feature elimination were used to select informative features per the two signs. Two radiomics models were constructed to predict MDR-TB using a random forest classifier. Then, a combined model was built incorporating radiomics features based on these two signs. The capability of the models in the combined training and testing cohorts was validated with ROC curves.

RESULTS

Sixteen features were extracted from TIB and 15 from nodules. The AUCs of the combined model were slightly higher than those of the TIB model in the combined training cohort (0.911 versus 0.877, p > 0.05) and testing cohort (0.820 versus 0.786, p < 0.05) and similar to the performance of the nodules model in the combined training cohort (0.911 versus 0.933, p > 0.05) and testing cohort (0.820 versus 0.855, p > 0.05).

CONCLUSIONS

The CT-based radiomics models hold promise for use as a non-invasive tool in the prediction of MDR-TB.

CLINICAL RELEVANCE STATEMENT

Our study revealed that complementary information regarding MDR-TB can be provided by radiomics based on the TIB sign and nodules. The proposed radiomics models may be new markers to predict MDR in active TB patients.

KEY POINTS

• This is the first study to build, validate, and apply radiomics based on tree-in-bud sign and nodules for the prediction of MDR-TB. • The radiomics model showed a favorable performance for the identification of MDR-TB. • The combined model holds potential to be used as a diagnostic tool in routine clinical practice.

Airflow obstruction and chronic obstructive pulmonary disease are common in pulmonary tuberculosis even without sequelae findings on chest X-ray

PURPOSE

Pulmonary tuberculosis (TB) is a well-known risk factor for airflow obstruction and chronic obstructive pulmonary disease (COPD). The prognosis of TB without sequelae on chest X-ray (CXR) remains uncertain.

METHODS

We used the 2008-2009 Korea National Health and Nutrition Examination Survey (KNHANES) data and 2007-2012 KNHANES-matched Health Insurance Review and Assessment Service cohort data. Airflow obstruction was assessed using a pulmonary function test. COPD was defined using diagnostic codes and the use of COPD medication for 3-year. We classified subjects into three groups based on TB history and sequelae on CXR.

RESULTS

In 4911 subjects, the CXR(-) (no TB sequelae on CXR) post-TB group (n = 134) showed similar characteristics and normal lung function compared to that of the control group (n = 4,405), while the CXR(+) (TB sequelae on CXR) post-TB group (n = 372) showed different characteristics and reduced lung function. The prevalence of airflow obstruction was 9.3%, 13.4%, and 26.6% in control, CXR(-) post-TB, and CXR(+) post-TB groups, respectively. COPD was more common in the post-TB with CXR(+) (6.5%) or without CXR (-) (4.5%) groups, than in the control group (1.8%). Compared to the CXR(-) post-TB group, the control group showed a lower risk for airflow obstruction (OR, 0.774; p = .008). The CXR(+) post-TB group showed a higher risk for airflow obstruction (OR, 1.456; p = .011). The Control group also showed a lower risk for the development of COPD than the CXR(-) post-TB group (OR, 0.496; p = .011).

CONCLUSIONS

We need to educate TB patients that airway obstruction and COPD can easily develop, even if TB sequelae are not observed on CXR.

Tuberculosis revisted: classic imaging findings in childhood

Tuberculosis (TB) remains one of the major public health threats worldwide, despite improved diagnostic and therapeutic methods. Tuberculosis is one of the main causes of infectious disease in the chest and is associated with substantial morbidity and mortality in paediatric populations, particularly in low- and middle-income countries. Due to the difficulty in obtaining microbiological confirmation of pulmonary TB in children, diagnosis often relies on a combination of clinical and radiological findings. The early diagnosis of central nervous system TB is challenging with presumptive diagnosis heavily reliant on imaging. Brain infection can present as a diffuse exudative basal leptomeningitis or as localised disease (tuberculoma, abscess, cerebritis). Spinal TB may present as radiculomyelitis, spinal tuberculoma or abscess or epidural phlegmon. Musculoskeletal manifestation accounts for 10% of extrapulmonary presentations but is easily overlooked with its insidious clinical course and non-specific imaging findings. Common musculoskeletal manifestations of TB include spondylitis, arthritis and osteomyelitis, while tenosynovitis and bursitis are less common. Abdominal TB presents with a triad of pain, fever and weight loss. Abdominal TB may occur in various forms, as tuberculous lymphadenopathy or peritoneal, gastrointestinal or visceral TB. Chest radiographs should be performed, as approximately 15% to 25% of children with abdominal TB have concomitant pulmonary infection. Urogenital TB is rare in children. This article will review the classic radiological findings in childhood TB in each of the major systems in order of clinical prevalence, namely chest, central nervous system, spine, musculoskeletal, abdomen and genitourinary system.

A high-resolution 3D atlas of the spectrum of tuberculous and COVID-19 lung lesions

Our current understanding of the spectrum of TB and COVID-19 lesions in the human lung is limited by a reliance on low-resolution imaging platforms that cannot provide accurate 3D representations of lesion types within the context of the whole lung. To characterize TB and COVID-19 lesions in 3D, we applied micro/nanocomputed tomography to surgically resected, postmortem, and paraffin-embedded human lung tissue. We define a spectrum of TB pathologies, including cavitary lesions, calcium deposits outside and inside necrotic granulomas and mycetomas, and vascular rearrangement. We identified an unusual spatial arrangement of vasculature within an entire COVID-19 lobe, and 3D segmentation of blood vessels revealed microangiopathy associated with hemorrhage. Notably, segmentation of pathological anomalies reveals hidden pathological structures that might otherwise be disregarded, demonstrating a powerful method to visualize pathologies in 3D in TB lung tissue and whole COVID-19 lobes. These findings provide unexpected new insight into the spatial organization of the spectrum of TB and COVID-19 lesions within the framework of the entire lung.

MDR tuberculosis in elderly

Tuberculosis is very common in young population, but it has emerged in a significant number in geriatric/elderly population (>60 Yrs. of age) as the population is ageing. Most cases of TB in the elderly are linked to the reactivation of lesions that have remained dormant. The awakening of these lesions is attributable to changes in the immune system related to senescence. Mortality rate from tuberculosis remains higher in elderly patients. Diagnosis is difficult as symptoms of active TB are nonspecific and less pronounced in the elderly. MDR TB is known to occur in poorly compliant patients (non-adherence) and this can be a major issue in elderly due to loss of independence and frailty resulting in treatment failure. Multidisciplinary management, involving geriatricians and infectious disease specialists is essential throughout care to optimize a favourable outcome in these vulnerable patients.

Geriatric tuberculosis in India-challenges and solutions

India has the highest burden of tuberculosis (TB) in the world. Despite a national program for control and elimination of TB, there is a lot to achieve to effectively diagnose and treat TB. One important aspect that often remains ignored is geriatric TB. This article focuses on the challenges in clinical presentation, diagnosis and treatment of geriatric TB along with some suggested solutions.

A comparison of the chest radiographic and computed tomographic features of subclinical pulmonary tuberculosis

Subclinical pulmonary tuberculosis (PTB) is a recently described intermediate state of great interest, but about which little is known. This study sought to describe and compare the frequency of key radiologic features of subclinical PTB on chest radiograph (CXR) versus computed tomographic scan (CT), and to interpret the clinical and public health relevance of the differences. Diagnostic CXRs and CT scans of the thorax and neck in a 16-year cohort of subclinical PTB patients in Canada were re-acquired and read by two independent readers and arbitrated by a third reader. Logistic regression models were fit to determine how likely CXR features can be detected by CT scan versus CXR after adjustment for age and sex. Among 296 subclinical patients, CXRs were available in 286 (96.6%) and CT scans in 94 (32.9%). CXR features in patients with and without CT scans were comparable. Lung cavitation was 4.77 times (95% CI 1.95–11.66), endobronchial spread 19.36 times (95% CI 8.05–46.52), and moderate/far-advanced parenchymal disease 3.23 times (95% CI 1.66–6.30), more common on CT scan than CXR. We conclude that the extent to which CXRs under-detect key radiologic features in subclinical PTB is substantial. This may have public health and treatment implications.

The Atypical Manifestation of Pulmonary Tuberculosis in Patients with Bronchial Anthracofibrosis

It has been stated that bronchial anthracofibrosis (BAF) has an important relationship with pulmonary tuberculosis (TB), and the coexistence of TB and BAF is high. The purpose of this study was to compare the differences in computed tomography (CT) characteristics of pulmonary TB according to the presence of underlying BAF. Total of 202 consecutive patients who were diagnosed with pulmonary TB and underwent bronchoscopy and CT in our institution were retrospectively reviewed. We classified the patients into two groups according to the presence of BAF and compared the clinicoradiological findings between the two groups (anthracofibrosis group vs. nonanthracofibrosis group). Elderly and female patients were significantly higher in anthracofibrosis group (mean age 79 ± 7 (64−94) vs. 56 ± 17 (16−95), p < 0.001; female 89% vs. 29%, p < 0.001). The frequency of internal low-density area or focal contour bulge within atelectasis (64% vs. 1%, p < 0.001), lower lobe predominance (43% vs. 9%, p < 0.001), endobronchial involvement (46% vs. 15%, p < 0.001), and lymphadenopathy (57% vs. 28%, p = 0.002) were significantly higher in anthracofibrosis group. In contrast, the anthracofibrosis group showed lower frequency of upper lobe predominance (32% vs. 81%, p < 0.001) and cavitation (14% vs. 51%, p = 0.001). In conclusion, being aware of these atypical manifestations of pulmonary TB in the presence of BAF will be of great help in early detection of TB.

Evaluation of radiological sequelae after treatment completion in new cases of pulmonary and pleural tuberculosis

Background

The objective of this study was to evaluate the residual parenchymal and pleural lesions on chest X-ray posttherapy in new tuberculosis (TB) cases.

Methods

This prospective study was done from January 2018 to December 2020, which involved the evaluation of medical records of 60 pulmonary or pleural TB patients who underwent successful treatment. Chest X-rays of the patients at the start and end of treatment were studied as per the guidelines by Revised National Tuberculosis Control Program. The primary outcome measures were residual chest X-ray lesions after the complete treatment of new cases of TB. Secondary outcomes measures were significant factors affecting the chest X-ray clearance.

Results

Chest X-ray showed clearing in 48.33% of cases. Residual chest X-ray findings were present in 31 cases which mainly included fibrosis in 23.33% and pleural thickening in 20%. None of the clinical and demographic characters and biochemical parameters showed significant association with chest X-ray clearance (P > 0.05). Sputum microscopy was done in 45 cases of which 25 (41.66%) were positive for acid-fast bacilli. Sputum positivity showed no significant correlation with chest X-ray clearance (odds ratio [OR]: 0.734, confidence interval [CI]: 0.224-2.411, P = 0.592). Compared to nonstandardized regimen, standardized regimen showed no significant correlation with chest X-ray clearance (OR: 0.664; CI: 0.233-1.892, P = 0.426).

Conclusion

Residual radiological sequelae were seen in more than half of the study subjects who were successfully treated for TB (51.67%). Demographic, clinical characteristics, sputum positivity, and treatment regimen showed no significant association with chest X-ray clearance.

Tuberculosis in the Elderly

The tuberculosis (TB) epidemic is most prevalent in the elderly, and there is a progressive increase in the notification rate with age. Most cases of TB in the elderly are linked to the reactivation of lesions that have remained dormant. The awakening of these lesions is attributable to changes in the immune system related to senescence. The mortality rate from tuberculosis remains higher in elderly patients. Symptoms of active TB are nonspecific and less pronounced in the elderly. Diagnostic difficulties in the elderly are common in many diseases but it is important to use all possible techniques to make a microbiological diagnosis. Recognising frailty to prevent loss of independence is a major challenge in dealing with the therapeutic aspects of elderly patients. Several studies report contrasting data about poorer tolerance of TB drugs in this population. Adherence to antituberculosis treatment is a fundamental issue for the outcome of treatment. Decreased completeness of treatment was shown in older people as well as a higher risk of treatment failure.

New Approaches in the Classification and Prognosis of Sign Clusters on Pulmonary CT Images in Patients With Multidrug-Resistant Tuberculosis

Background: To date, radiographic sign clusters of multidrug-resistant pulmonary tuberculosis (MDR-TB) patients have not been reported. We conducted a study to investigate the classification and prognosis of sign clusters in pulmonary Computed Tomography (CT) images from patients with MDR-TB for the first time by using principal component analysis (PCA).

Methods: The clinical data and pulmonary CT findings of 108 patients with MDR-TB in the Liupanshui Third Hospital were collected (from January 2018 to December 2020). PCA was used to analyze the sign clusters on pulmonary CT, and receiver operating characteristic (ROC) analysis was used to analyze the predictive value of the treatment outcome of MDR-TB patients.

Results: Six cluster signs of MDR-TB were determined by PCA: nodules, infiltration, consolidation, cavities, destroyed lung and non-active lesions. Nine months after treatment, the area under the ROC curve (AUC) of MDR-TB patients with a cavity sign cluster was 0.818 (95% CI: 0.733–0.886), and the positive predictive value (PPV) and negative predictive value (NPV) of the treatment outcome were 79.6% (95% CI: 65.7–89.8%) and 72.9% (95% CI: 59.7–83.6%), respectively.

Conclusion: PCA plays an important role in the classification of sign groups on pulmonary CT images of MDR-TB patients, and the sign clusters obtained from PCA are of great significance in predicting the treatment outcome.

Differentiating between active and latent tuberculosis with chest computed tomography

PURPOSE

The purpose of this study was to evaluate the capabilities of chest computed tomography (CT) in distinguishing between active and latent tuberculosis in patients positive for interferon-gamma release assay (IGRA) testing, and to compare the performance of CT with that of quantitative IGRA testing in a low incidence setting.

MATERIALS AND METHODS

Patients with latent or active tuberculosis define by an IGRA positive test were retrospectively recruited. Sensitivity, specificity and accuracy were determined for CT variables and quantitative IGRA results. Final diagnosis of active tuberculosis was based on clinical data and microbiological culture. Univariable and multivariable analyses were performed using logistic regression model to identify CT variables associated with the diagnosis of active tuberculosis.

RESULTS

A total of 92 patients with positive IGRA results who underwent CT examination were included. There were 54 men and 38 women with a mean age of 53.5±18 (SD) years (range: 40-68 years). Of them, 22 patients (24%) had positive Mycobacterium tuberculosis culture and 70 (76%) had latent tuberculosis. Among CT variables, consolidation had the greatest sensitivity (77%; 95%CI: 60-95%) and "tree-in-bud" the greatest specificity (97%; 95% CI: 93-100%) for the diagnosis of active tuberculosis. At univariable analysis "tree-in-bud", splenic calcification and non-calcified lung nodules were the significant variables independently associated with active tuberculosis. At multivariable analysis, the adjusted odds ratio of "tree-in-bud" was 42.91 (95% CI: 5.62-327.42). Using an optimal threshold of 51 spots, quantitative IGRA yielded 64% sensitivity (95% CI: 44-84%) and 61% specificity (95% CI: 50-73%) for the diagnosis of active tuberculosis.

CONCLUSIONS

In a low incidence setting, chest CT, especially when "tree-in-bud" pattern is present, is superior to quantitative IGRA testing to identify patients with active tuberculosis among those with positive IGRA testing.

Distinguishing nontuberculous mycobacteria from Mycobacterium tuberculosis lung disease from CT images using a deep learning framework

Purpose

To develop and evaluate the effectiveness of a deep learning framework (3D-ResNet) based on CT images to distinguish nontuberculous mycobacterium lung disease (NTM-LD) from Mycobacterium tuberculosis lung disease (MTB-LD).

Method

Chest CT images of 301 with NTM-LD and 804 with MTB-LD confirmed by pathogenic microbiological examination were retrospectively collected. The differences between the clinical manifestations of the two diseases were analysed. 3D-ResNet was developed to randomly extract data in an 8:1:1 ratio for training, validating, and testing. We also collected external test data (40 with NTM-LD and 40 with MTB-LD) for external validation of the model. The activated region of interest was evaluated using a class activation map. The model was compared with three radiologists in the test set.

Result

Patients with NTM-LD were older than those with MTB-LD, patients with MTB-LD had more cough, and those with NTM-LD had more dyspnoea, and the results were statistically significant (p < 0.05). The AUCs of our model on training, validating, and testing datasets were 0.90, 0.88, and 0.86, respectively, while the AUC on the external test set was 0.78. Additionally, the performance of the model was higher than that of the radiologist, and without manual labelling, the model automatically identified lung areas with abnormalities on CT > 1000 times more effectively than the radiologists.

Conclusion

This study shows the efficacy of 3D-ResNet as a rapid auxiliary diagnostic tool for NTB-LD and MTB-LD. Its use can help provide timely and accurate treatment strategies to patients with these diseases.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-021-05432-x.

Diagnosis of tuberculosis: a consensus statement from the Brazilian Thoracic Association

Early, accurate diagnosis of tuberculosis is one of the major pillars of the control of the disease. The purpose of this consensus statement is to provide health professionals with the most current, useful evidence for the diagnosis of tuberculosis in Brazil. To that end, the Tuberculosis Committee of the Brazilian Thoracic Association brought together 14 members of the Association with recognized expertise in tuberculosis in Brazil to compose the statement. A nonsystematic review of the following topics was carried out: clinical diagnosis, bacteriological diagnosis, radiological diagnosis, histopathological diagnosis, diagnosis of tuberculosis in children, and diagnosis of latent tuberculosis infection.

Hafnia alvei pneumonia: a rare cause of infection in the multimorbid or immunocompromised

Hafnia alvei is a rare, poorly understood commensal bacterium which has, on occasion, been shown to infect humans. We present two cases. The first patient presented with a 1-week history of dyspnoea, pleurisy and a productive cough, and the second with a prodrome of fatigue and night sweats. The former had a history of severe chronic obstructive pulmonary disease and the latter had a history of Crohn's disease. Both patients had underlying comorbidities and immunosuppression, but differed in presentation, radiological findings and recovery. This case series aims to remind readers of the broad differential of pathogens that can lead to disease in the immunocompromised and that one should not dismiss atypical cultured bacteria as commensal too hastily.

COVID-19 and Tuberculosis

On March 11, 2020, the WHO declared that coronavirus disease 2019 (COVID-19) can be characterized as a pandemic based on the alarming levels of spread and severity and on the alarming levels of inaction. COVID-19 has received worldwide attention as emergency, endangering international public health and economic development. There is a growing body of literatures regarding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as well as COVID-19. This review will focus on the latest advance of epidemiology, pathogenesis, and clinical characteristics about COVID-19. Meanwhile, tuberculosis (TB) remains the leading representative respiratory tract communicable disease threatening public health. There are limited data on the risk of severe disease or outcomes in patients with concurrence of TB and COVID-19. Nevertheless, co-infection of some virus would aggravate TB, such as measles. And tuberculosis and influenza co-infection compared with tuberculosis single infection was associated with increased risk of death in individuals. This review will also introduce the characteristics about the concurrence of TB and emerging infectious diseases to provide a hint to manage current epidemic.

Endobronchial Tuberculosis: A Rare Presentation

Endobronchial tuberculosis (EBTB) is an infection of the tracheobronchial tree by Mycobacterium tuberculosis. It is common among young females. Patient can present with fever, cough, wheeze, with or without any constitutional symptoms. It presents as a diagnostic dilemma, as patient sputum smear can be false negative. CT scan may or may not show any abnormality, or any endobronchial lesion. Bronchoscopy with bronchoalveolar lavage and biopsy offers the diagnostic choice. We hereby report a case of a young immunocompetent Asian female who was found to have endobronchial pathology, leading to diagnosis and timely therapy. 

Aftermath of pulmonary tuberculosis: computed tomography assessment

Purpose

Pulmonary tuberculosis (PTB) has clinically significant sequelae, even after recommended treatment completion. It is important to recognise these sequelae for accurate assessment of severity and treatment planning, if indicated.

Material and methods

We retrospectively analysed contrast-enhanced computed tomography (CT) scans of chest of 100 patients with previous history of treated pulmonary tuberculosis, excluding those with active pulmonary disease. CT findings were analysed based on parenchymal, airway, pleural, mediastinal, and vascular sequelae of PTB.

Results

Parenchymal sequelae included fibrosis with architectural distortion and volume loss (90%), cavities (21%) (with aspergillomas noted in 19% of these cases), and tuberculomas (54%). Airway involvement was noted as bronchiectasis (77%) and bronchial stenosis (4%) but none with broncholithiasis. Mediastinal sequelae included lymph node calcification (74%), fibrosing mediastinitis (1%), and pericardial tuberculosis (2%). Pleural sequelae included pleural thickening (22%), with 40.9% of these patients showing calcifications, and one patient with chronic chylous pleural effusion. Vascular sequelae included Rasmussen aneurysms (4%), enlarged bronchial arteries (3%), and systemic bronchial collaterals in 1% of our patients.

Conclusions

PTB has multiple appalling sequelae, which require due attention and appropriate treatment in symptomatic cases. Radiological evaluation forms an integral part in patient assessment and decision making.

Comparison of the chest computed tomography findings between patients with pulmonary tuberculosis and those with Mycobacterium avium complex lung disease

BACKGROUND

Since the computed tomography (CT) findings of nontuberculous mycobacterial lung disease are similar to those of pulmonary tuberculosis (PTB), we often have difficulty differentiating the two. In this study, we compared the differences in chest CT findings and their locations between cases of PTB and Mycobacterium avium complex lung disease (MACLD).

METHODS

The subjects were 100 MACLD patients and 42 PTB patients treated at our hospital from May 2005 to August 2015. The CT findings were retrospectively evaluated.

RESULTS

PTB more frequently showed lung shadows with calcification inside the lesion, calcification of the mediastinal/hilar lymph node, and pleural effusion on CT than MACLD, while extensive bronchiectasis and granular/large shadows connected to bronchiectasis were more frequently observed with MACLD than PTB. For cavitary lesions, the thinnest part of the cavity wall with MACLD was thinner than that with PTB. Granular shadows, large shadows, and bronchiectasis were typically distributed to the right upper lobe and left upper division in PTB cases vs. the right intermediate lobe and left lingula in MACLD.

CONCLUSIONS

Chest CT findings would therefore be useful for distinguishing PTB and MACLD when typical findings are observed.

Clinical characteristics and chest computed tomography findings of smear-positive and smear-negative pulmonary tuberculosis in hospitalized adult patients

Pulmonary tuberculosis (PTB) continues to be one of the significant public health threats with significant morbidity and mortality. The present study was aimed to assess the clinical characteristics and chest computed tomography (CT) findings of smear-positive and smear-negative PTB in hospitalized adult patients.Hospitalized adult patients diagnosed with PTB by positive Mycobacterium tuberculosis growth on acid-fast bacilli culture from bronchial aspiration or sputum from 2015 to 2017 were reviewed. Only the patients who had chest CT within 14 days of the diagnosis of PTB were included. Medical records and CT images were analyzed.A total of 189 patients was enrolled. The median age was 62 years, and there were 118 males (62.4%). More than half of the patients had underlying chronic medical conditions (55.5%). The most common CT finding was nodular lesions (96.8%). The patients were categorized in 2 groups of smear-positive (n = 94, 49.7%) and smear-negative (n = 95, 50.3%). Between 2 groups, there was no difference in underlying medical conditions. However, there were more lesions of cavity, consolidation, bronchiectasis, upper lobe involvement, multiple lobe involvement, and lymphadenopathy in the smear-positive group. A predictive model for smear-positive tuberculosis was created based on the comparison analysis that had an area of 0.724 under the receiver operating characteristic curve. In a multivariate logistic regression analysis, CT findings of consolidation (odds ratio [OR] 2.521, 95% confidence interval [CI] 1.175-5.408, P = .02), lymphadenopathy (OR 1.947, 95% CI 1.025-3.696, P = .04), and multi-lobe involvement (OR 2.795, 95% CI 1.084-7.205, P = .03) were associated with smear-positive PTB.PTB patients who have chest CT findings of cavity, consolidation, bronchiectasis, upper lobe involvement, multiple lobe involvement, and lymphadenopathy may be at higher risk for smear-positive TB. A predictive model may be helpful for further assessment.

Increasing Number and Volume of Cavitary Lesions on Chest Computed Tomography Are Associated With Prolonged Time to Culture Conversion in Pulmonary Tuberculosis

Background

Cavitary lesions (CLs) primarily identified by chest x-ray (CXR) have been associated with worse clinical outcomes among patients with pulmonary tuberculosis (PTB). Chest computed tomography (CT), which has better resolution and increased sensitivity to detect lung abnormalities, has been understudied in PTB patients. We compared detection of CLs by CT and CXR and assessed their association with time to sputum culture conversion (tSCC).

Methods

This was a retrospective cohort study of 141 PTB patients who underwent CT. We used multivariate Cox proportional hazards models to evaluate the association between CLs on CXR and the number and single largest volume of CLs on CT with tSCC.

Results

Thirty (21%) and 75 (53%) patients had CLs on CXR and CT, respectively. CT detected cavities in an additional 44 patients (31%) compared with CXR. After multivariable adjustment, we observed a negative association between CLs and tSCC, with an adjusted hazard ratio (aHR) of 0.56 (95% confidence interval [CI], 0.32 to 0.97) for single CLs and 0.31 (95% CI, 0.16 to 0.60) for multiple CLs present on CT. Patients with a CL volume ≥25 mL had a prolonged tSCC (aHR, 0.39; 95% CI, 0.21 to 0.72). CLs on CXR were not associated with increased tSCC after multivariable adjustment.

Conclusions

CT detected a larger number of cavities in patients with PTB relative to CXR. We observed an association between increasing number and volume of CLs on CT and delayed tSCC independent of sputum microscopy result. Our findings highlight a potential role for CT in the clinical and research setting as a tool to risk-stratify patients with PTB.

High-resolution computed tomography findings of pulmonary tuberculosis in lung transplant recipients

OBJECTIVE

Respiratory infections constitute a major cause of morbidity and mortality in solid organ transplant recipients. The incidence of pulmonary tuberculosis is high among such patients. On imaging, tuberculosis has various presentations. Greater understanding of those presentations could reduce the impact of the disease by facilitating early diagnosis. Therefore, we attempted to describe the HRCT patterns of pulmonary tuberculosis in lung transplant recipients.

METHODS

From two hospitals in southern Brazil, we collected the following data on lung transplant recipients who developed pulmonary tuberculosis: gender; age; symptoms; the lung disease that led to transplantation; HRCT pattern; distribution of findings; time from transplantation to pulmonary tuberculosis; and mortality rate. The HRCT findings were classified as miliary nodules; cavitation and centrilobular nodules with a tree-in-bud pattern; ground-glass attenuation with consolidation; mediastinal lymph node enlargement; or pleural effusion.

RESULTS

We evaluated 402 lung transplant recipients, 19 of whom developed pulmonary tuberculosis after transplantation. Among those 19 patients, the most common HRCT patterns were ground-glass attenuation with consolidation (in 42%); cavitation and centrilobular nodules with a tree-in-bud pattern (in 31.5%); and mediastinal lymph node enlargement (in 15.7%). Among the patients with cavitation and centrilobular nodules with a tree-in-bud pattern, the distribution was within the upper lobes in 66.6%. No pleural effusion was observed. Despite treatment, one-year mortality was 47.3%.

CONCLUSIONS

The predominant HRCT pattern was ground-glass attenuation with consolidation, followed by cavitation and centrilobular nodules with a tree-in-bud pattern. These findings are similar to those reported for immunocompetent patients with pulmonary tuberculosis and considerably different from those reported for AIDS patients with the same disease.

Role of Xpert MTB/RIF in Bronchoalveolar lavage fluid of sputum-scarce, suspected Pulmonary TB patients

Setting

A prospective observational study conducted in Medical college hospital, in a high-TB- prevalence region of northern Telangana, India.

Objective

To know the diagnostic role of Xpert MTB/RIF assay in bronchoalveolar lavage fluid (BALF) in sputum-scarce, suspected pulmonary tuberculosis (PTB) patients.

Design

Study period was between October 2014 and March 2017. Suspected pulmonary tuberculosis patients aged 15 years or more, who were sputum-scarce and conforming to the inclusion criteria were submitted to bronchoscopy. BALF thus obtained was submitted to smear for acid fast bacilli (AFB) and Xpert MTB/RIF assay as index tests along with culture for Mycobacterium tuberculosis complex (MTBC). Culture for M. tuberculosis complex was considered as gold standard for the diagnosis of PTB. The sensitivity, specificity and predictive values were calculated for smear AFB and Xpert MTB/RIF assay.

Results

56 of the 81 patients were included and evaluated in the final analysis. In 10 of these 56 patients PTB was confirmed by culture positivity. The sensitivity and specificity of Xpert MTB/RIF assay was 90% (9/10,95%CI 59.6- 98.2) and 52.2% (24/46, 95%CI 38. 1-65.9) respectively and that of the smear AFB was 60% (6/10, 95%CI 31.2–83.1) and 67.4% (31/46, 95%CI 53.0–79.1). All the patients considered ‘probable’ PTB (pending culture results), were administered antituberculous treatment and showed complete clinicoradiological improvement on follow up. Three of the 31 Xpert MTB/RIF positive patients were detected as resistance to rifampicin (RR).

Conclusions

Xpert MTB/RIF assay of BALF in the study cohort provides rapid diagnosis of Mycobacterium tuberculosis, and detection of rifampicin resistance at the very outset, aiding in selection of appropriate ATT regimen. In this context, it can be recommended as the first line investigation. Xpert MTB/RIF assay aided by HRCT Chest and suggestive clinical presentation may be helpful in early institution of ATT especially in smear negative, culture negative cases.

Medical management of drug-sensitive active thoracic tuberculosis: the work-up, radiographic findings and treatment

Tuberculosis (TB) infection and disease have plagued human civilization across time and led to immeasurable morbidity and mortality. This review article focuses on the most currently available information regarding the diagnostic workup, radiologic presentation and treatment of drug-sensitive active TB. As discussed, if adequate resources and methods are available to diagnose, evaluate, and treat patients, drug sensitive TB is an imminently curable disease.

Appropriateness and clinical outcome of chest computed tomography without intravenous contrast: A study conducted in Pakistan

BACKGROUND

Chest computed tomography (CT), including high-resolution CT (HRCT), has become an integral part of modern healthcare. It enables the physician to arrive at a diagnosis using a noninvasive approach. Our practice has shown that various chest CT scans without intravenous (IV) contrast, including HRCT, have no proper clinical indication. For the same reason, we have assessed the appropriateness of chest CT without IV contrast based on the evidence-based American College of Radiology (ACR) appropriateness criteria.

METHODS

Chest CT scans without IV contrast were reviewed to evaluate if the examination was based upon the evidence-based ACR appropriateness criteria. All clinical indications, positive physical examination findings, laboratory test findings, and radiological records submitted at the time of chest CT were reviewed.

RESULTS

Of 1205 CT scans, 538 (44.6%) were considered "inappropriate," 367 (30.4%) were considered "appropriate," and 300 (24.8%) were considered "may be appropriate." CT scans were performed on 241 (20.0%) patients with no clinical history, whereas 148 (12.3%) examinations in patients aged < 40 years were performed with no positive physical finding. Positive results that affected the management were 4.43 times more likely to be considered appropriate than inappropriate (adjusted odds ratio, 4.43; 95% confidence interval, 1.81-10.87).

CONCLUSIONS

This study showed a high percentage of chest CT scans without IV contrast examinations not meeting the ACR appropriateness criteria. Chest CT is a valuable tool for evaluation of chest diseases only in the presence of adequate detailed history and physical examination.

Tuberculosis and lung damage: from epidemiology to pathophysiology

A past history of pulmonary tuberculosis (TB) is a risk factor for long-term respiratory impairment. Post-TB lung dysfunction often goes unrecognised, despite its relatively high prevalence and its association with reduced quality of life. Importantly, specific host and pathogen factors causing lung impairment remain unclear. Host immune responses probably play a dominant role in lung damage, as excessive inflammation and elevated expression of lung matrix-degrading proteases are common during TB. Variability in host genes that modulate these immune responses may determine the severity of lung impairment, but this hypothesis remains largely untested. In this review, we provide an overview of the epidemiological literature on post-TB lung impairment and link it to data on the pathogenesis of lung injury from the perspective of dysregulated immune responses and immunogenetics.

Host factors driving lung injury in TB likely contribute to variable patterns of pulmonary impairment after TBhttp://ow.ly/a3of30hBsxB

Validation of a model for predicting smear-positive active pulmonary tuberculosis in patients with initial acid-fast bacilli smear-negative sputum

OBJECTIVES

The objective of this study was to develop a predictive model for final smear-positive (SP) active pulmonary tuberculosis (aPTB) in patients with initial negative acid fast bacilli (AFB) sputum smears (iSN-SP-aPTB) based on high-resolution computed tomography (HRCT).

METHOD AND MATERIALS

Eighty (126, 21) patients of iSN-SP-aPTB and 402 (459, 876) patients of non-initial positive acid fast bacilli (non-iSP) pulmonary disease without iSN-SP-aPTB were included in a derivation (validation, prospective) cohort. HRCT characteristics were analysed, and multivariable regression and receiver operating characteristic (ROC) curve analysis was performed to develop a score predictive of iSN-SP-aPTB.

RESULTS

The derivation cohort showed clusters of nodules/mass of the right upper lobe or left upper lobe were independent predictors of iSN-SP-aPTB, while bronchiectasis in the right middle lobe or left lingual lobe were negatively associated with iSN-SP-aPTB. A predictive score for iSN-SP-aPTB based on these findings was tested in the validation and prospective cohorts. With an ideal cut-off score = 1, the sensitivity, specificity, positive predictive value, and negative predictive value of the prediction model were 87.5% (90%, 90.5%), 99% (97.1%, 98.4%), 94.6% (81.3%, 57.5%), and 97.6% (97%, 99.8%) in the derivation (validation, prospective) cohorts, respectively.

CONCLUSIONS

The model may help identify iSN-SP-aPTB among patients with non-iSP pulmonary diseases.

KEY POINTS

• Smear-positive active pulmonary tuberculosis that is initial smear-negative (iSN-SP-aPTB) is infectious. • High-resolution computed tomography can identify iSN-SP-aPTB among non-iSP pulmonary diseases. • Clusters nodules/mass in right/left upper lobe are positively associated with iSN-SP-aPTB. • Bronchiectasis in right middle/left lingual lobe is negatively associated with iSN-SP-aPTB. • The model may have high post-test probability in identifying iSN-SP-aPTB.

Pulmonary Tuberculosis

This review on pulmonary tuberculosis includes an introduction that describes how the lung is the portal of entry for the tuberculosis bacilli to enter the body and then spread to the rest of the body. The symptoms and signs of both primary and reactivation tuberculosis are described. Routine laboratory tests are rarely helpful for making the diagnosis of tuberculosis. The differences between the chest X ray in primary and reactivation tuberculosis is also described. The chest computed tomography appearance in primary and reactivation tuberculosis is also described. The criteria for the diagnosis of pulmonary tuberculosis are described, and the differential is discussed. The pulmonary findings of tuberculosis in HIV infection are described and differentiated from those in patients without HIV infection. The occurrence of tuberculosis in the elderly and in those patients on anti-tumor necrosis factor alpha inhibitors is described. Pleural tuberculosis and its diagnosis are described. Efforts to define the activity of tuberculosis and the need for respiratory isolation are discussed. The complications of pulmonary tuberculosis are also described.

Endobronchial tuberculosis-a review

Endobronchial tuberculosis (EBTB) is a tuberculous infection of the tracheobronchial tree with microbial and histopathological evidence. Patients may present with symptoms secondary to disease itself or from the complication of disease like endobronchial obstruction. Diagnosis requires a high index of suspicion. Computed tomography (CT) and bronchoscopy along with microbiological investigations are the most useful diagnostic tools for the confirmation as well as for the evaluation of the tracheobronchial stenosis. The goals of treatment are eradication of tubercle bacilli with anti-tubercular medications and the prevention of airway stenosis. Interventional Bronchoscopic techniques and surgery is required for those patients who develop severe tracheobronchial stenosis that causing significant symptoms including dyspnea, repeated post obstructive pneumonia or bronchiectasis.

Cord factor as an invisibility cloak? A hypothesis for asymptomatic TB persistence

Mycobacterium tuberculosis (MTB) has long been known to persist in grossly normal tissues even in people with active lesions and granulomas in other parts of the body. We recently reported that post-primary TB begins as an asymptomatic infection that slowly progresses, accumulating materials for a massive necrotizing reaction that results in cavitation. This paper explores the possible roles of trehalose 6,6' dimycolate (TDM) or cord factor in the ability of MTB to persist in such lesions without producing inflammation. TDM is unique in that it has three distinct sets of biologic activities depending on its physical conformation. As a single molecule, TDM stimulates macrophage C-type lectin receptors including Mincle. TDM can also form three crystal like structures, cylindrical micelles, intercalated bilayer and monolayer, that have distinct non receptor driven activities that depend on modulation of interactions with water. In the monolayer form, TDM is highly toxic and destroys cells in minutes upon contact. The cylindrical micelles and an intercalated bilayer have surfaces composed entirely of trehalose which protect MTB from killing in macrophages. Here we review evidence that these trehalose surfaces bind water. We speculate that this immobilized water constituites of an "invisibility cloak" that facilitates the persistence of MTB in multiple cell types without producing inflammation, even in highly immune individuals.

Imaging of Diseases of the Large Airways

Imaging of the large airways is key to the diagnosis and management of a wide variety of congenital, infectious, malignant, and inflammatory diseases. Involvement can be focal, regional, or diffuse, and abnormalities can take the form of masses, thickening, narrowing, enlargement, or a combination of patterns. Recognition of the typical morphologies, locations, and distributions of large airways disease is central to an accurate imaging differential diagnosis.

The relation between CT findings and sputum microbiology studies in active pulmonary tuberculosis

PURPOSE

To evaluate whether CT findings suggesting active pulmonary tuberculosis correlate with sputum microbiological studies, and to determine whether CT could predict infectivity.

MATERIALS AND METHODS

Total 108 patients with active pulmonary tuberculosis were enrolled. We reviewed CT findings and sputum microbiological studies. Then, we analyzed the statistical difference in CT findings between the positive and negative groups of each sputum microbiological study (AFB smear, PCR, and culture). Also, we divided the patients into five groups according to sputum AFB smear grade and analyzed linear trends of CT findings between the five groups.

RESULTS

Both frequencies and extents of centrilobular micronodules (63% vs 38%, p=0.011 for frequency; 1.6 ± 1.6 vs 0.6 ± 1.1, p=0.001 for extent), tree-in-bud opacities (63% vs 33%, p=0.002; 1.6 ± 1.6 vs 0.5 ± 0.9, p<0.001, respectively), consolidation (98% vs 81%, p=0.003; 2.7 ± 1.5 vs 1.3 ± 1.1, p<0.001, respectively), and cavitation (86% vs 33%, p<0.001; 1.5 ± 1.2 vs 0.4 ± 0.7, p<0.001, respectively), were significantly increased in the sputum AFB-positive group than in the negative group. These four CT findings were increase in frequency and extent in the sputum PCR-positive group with or without statistical significance. They did not show significant differences between the sputum culture-positive and negative groups. As the AFB smear grade increased, frequencies and extents of centrilobular micronodules, tree-in-bud, consolidation, and cavitation also increased.

CONCLUSION

CT features representing active tuberculosis-centrilobular nodules, tree-in-bud, consolidation, and, cavitation-strongly correlate with the positivity and grading of AFB smear.

PET/CT imaging correlates with treatment outcome in patients with multidrug-resistant tuberculosis

Definitive clinical trials of new chemotherapies for treating tuberculosis (TB) require following subjects until at least 6 months after treatment discontinuation to assess for durable cure, making these trials expensive and lengthy. Surrogate endpoints relating to treatment failure and relapse are currently limited to sputum microbiology, which has limited sensitivity and specificity. We prospectively assessed radiographic changes using 2-deoxy-2-[(18)F]-fluoro-D-glucose (FDG) positron emission tomography/computed tomography (PET/CT) at 2 and 6 months (CT only) in a cohort of subjects with multidrug-resistant TB, who were treated with second-line TB therapy for 2 years and then followed for an additional 6 months. CT scans were read semiquantitatively by radiologists and were computationally evaluated using custom software to provide volumetric assessment of TB-associated abnormalities. CT scans at 6 months (but not 2 months) assessed by radiologist readers were predictive of outcomes, and changes in computed abnormal volumes were predictive of drug response at both time points. Quantitative changes in FDG uptake 2 months after starting treatment were associated with long-term outcomes. In this cohort, some radiologic markers were more sensitive than conventional sputum microbiology in distinguishing successful from unsuccessful treatment. These results support the potential of imaging scans as possible surrogate endpoints in clinical trials of new TB drug regimens. Larger cohorts confirming these results are needed.

Quantification of Pulmonary Inflammatory Processes Using Chest Radiography: Tuberculosis as the Motivating Application

The purpose of this work was to develop a quantitative method for evaluating the pulmonary inflammatory process (PIP) through the computational analysis of chest radiography exams in posteroanterior (PA) and lateral views. The quantification procedure was applied to patients with tuberculosis (TB) as the motivating application.A study of high-resolution computed tomography (HRCT) examinations of patients with TB was developed to establish a relation between the inflammatory process and the signal difference-to-noise ratio (SDNR) measured in the PA projection. A phantom essay was used to validate this relation, which was implemented using an algorithm that is able to estimate the volume of the inflammatory region based solely on SDNR values in the chest radiographs of patients.The PIP volumes that were quantified for 30 patients with TB were used for comparisons with direct HRCT analysis for the same patient. The Bland-Altman statistical analyses showed no significant differences between the 2 quantification methods. The linear regression line had a correlation coefficient of R = 0.97 and P < 0.001, showing a strong association between the volume that was determined by our evaluation method and the results obtained by direct HRCT scan analysis.Since the diagnosis and follow-up of patients with TB is commonly performed using X-rays exams, the method developed herein can be considered an adequate tool for quantifying the PIP with a lower patient radiation dose and lower institutional cost. Although we used patients with TB for the application of the method, this method may be used for other pulmonary diseases characterized by a PIP.

Efficacy of Induced Sputum for the Diagnosis of Pulmonary Tuberculosis in Adults Unable to Expectorate Sputum

Background

Induced sputum (IS) has been used to collect airway secretions in subjects who have inadequate sputum production. The aim of this study was to investigate the efficacy of IS for the diagnosis of pulmonary tuberculosis (PTB) in adults unable to expectorate sputum.

Methods

Medical records of 39 PTB patients who underwent IS due to absence of spontaneous sputum production between January 2011 and March 2014 at a tertiary hospital in South Korea were reviewed. Results of acid fast bacilli smear, Mycobacterium tuberculosis culture and polymerase chain reaction assay for M. tuberculosis (TB-PCR) of IS specimens from these patients were analyzed. Clinical and high-resolution computed tomography (HRCT) characteristics were also analyzed to find characteristics associated with IS culture positivity.

Results

Of the 39 IS specimens from PTB patients, 7 (17.9%) were smear positive and 31 (79.5%) were culture positive. Twenty-four IS specimens were tested for TB-PCR and 13 (54.2%) were positive on TB-PCR. Multivariate analysis showed that younger age (p=0.04) and presence of tree-in-bud appearance on HRCT (p=0.03) were independent predictors of IS culture positivity.

Conclusion

IS is useful for the diagnosis of PTB in adults unable to expectorate sputum. Younger age and tree-in-bud appearance on HRCT were associated with IS culture positivity in these patients.

Role of digital tomosynthesis and dual energy subtraction digital radiography in detection of parenchymal lesions in active pulmonary tuberculosis

OBJECTIVE

To assess the role of digital tomosynthesis (DTS) and dual energy subtraction digital radiography (DES-DR) in detection of parenchymal lesions in active pulmonary tuberculosis (TB) and to compare them with digital radiography (DR).

MATERIALS AND METHODS

This prospective study was approved by our institutional review committee. DTS and DES-DR were performed in 62 patients with active pulmonary TB within one week of multidetector computed tomography (MDCT) study. Findings of active pulmonary TB, that is consolidation, cavitation and nodules were noted on digital radiography (DR), DTS and DES-DR in all patients. Sensitivity, specificity, positive and negative predictive values of all 3 modalities was calculated with MDCT as reference standard. In addition presence of centrilobular nodules was also noted on DTS.

RESULTS

Our study comprised of 62 patients (33 males, 29 females with age range 18-82 years). Sensitivity and specificity of DTS for detection of nodules and cavitation was better than DR and DES-DR. Sensitivity and specificity of DTS for detection of consolidation was comparable to DR and DES-DR. DES-DR performed better than DR in detection of nodules and cavitation. DTS was also able to detect centrilobular nodules with sensitivity and specificity of 57.4% and 86.5% respectively.

CONCLUSION

DTS and DES-DR perform better than DR in detection of nodules, consolidation and cavitation in pulmonary TB. DTS gives better results than DES-DR, particularly in detection of cavitation and has moderate sensitivity for detection of centrilobular nodules. Thus DTS can be used for evaluation of patients of suspected pulmonary TB, thereby giving a more confident diagnosis of active disease and also in follow up.

Evaluation of the radiological sequelae after treatment completion in new cases of pulmonary, pleural, and mediastinal tuberculosis

Background:

Residual radiological lesions may persist even after successful treatment of tuberculosis. There is insufficient data as to the nature and magnitude of these opacities in the treated cases of tuberculosis.

Aims and Objectives:

This study evaluates the nature and magnitude of residual radiological opacities and of complete radiological resolution in new successfully treated cases of tuberculosis.

Design:

Four hundred and forty one new cases of pulmonary, pleural or mediastinal tuberculosis were radiologically evaluated by chest x-ray, PA view, at the start and end of a successful treatment, which was as per the World Health Organization (WHO), Revised National Tuberculosis Control Program (RNTCP), and Directly Observed Treatment, Short-Course (DOTS) guidelines. Patients with a previous history of tuberculosis or other lung conditions, treatment failure, retreatment cases, and multidrug tuberculosis (MDR-TB) cases were excluded.

Results:

Residual x-ray lesions were seen in 178 cases of tuberculosis (40.36%). Complete radiological resolution was seen in 263 cases (59.64%). Of the residual lesions, 67.4% were parenchymal were parenchymal in nature, 23.59% were pleural lesions and 8.99% were mediastinal lesions. Out of the 126 sputum-positive cases, 70% (n = 88)had residual lesions on chest x-ray whereas of the 315 sputum-negative cases 28.5%, (n = 99) had radiological residual lesions.

Conclusion:

Residual radiological opacities are seen in a large proportion of treated cases of tuberculosis (40%). Pulmonary lesions show more residual lesions (67%) than pleural (23%) and mediastinal lesions (9%).

The imaging spectrum of pulmonary tuberculosis

Tuberculosis has still an important impact on public health because it is an important cause of death, particularly in developing countries. On the other hand recent studies have shown that tuberculosis is again becoming concentrated in big cities of Western Europe, especially among immigrants, drug addicts, poor people, and the homeless, despite progress in reducing national rates of the disease. Diagnostic imaging is challenging for radiologists because signs of tuberculosis may easily mimic other diseases such as neoplasms or sarcoidosis. Clinical signs and symptoms in affected adults can be non-specific and a high level of pre-test clinical suspicion based on history is fundamental in the diagnostic work-up. Impact of tuberculosis in the world is extremely important considering the high incidence estimated during 2011 that was 8.7 million cases. This article gives a review of imaging patterns of chest tuberculosis as may be detected on conventional radiography and computerized tomography (CT). The main aim is to improve radiologist's familiarity with the spectrum of imaging features of this disease and facilitate timely diagnosis. Furthermore, we consider the emerging role of alternative methods of imaging, such as magnetic resonance imaging (MRI), that can be helpful and highly accurate for a better definition of some signs of tuberculosis.

Tree-in-bud pattern in central lung cancer: CT findings and pathologic correlation

OBJECTIVES

Tree-in-bud (TIB) pattern can be found with central lung cancer on chest CT scans. However, few reports have described it so far. We aim to determine its incidence, CT findings and pathologic basis.

MATERIALS AND METHODS

652 consecutive patients with confirmed central lung cancer were enrolled in our study. The incidence, CT findings and pathologic features of TIB pattern were analyzed retrospectively.

RESULTS

In total, TIB pattern was found in 22.5% (147/652) of patients. It was more common in patients with squamous cell carcinoma than those with non-squamous cell carcinoma (P=0.000). The most important associated CT finding was obstructive bronchial mucoid impaction distal to the cancer (100%, 147/147), followed by consolidation and ground-glass opacities (62.6%, 92/147). TIB pattern was confined to the areas of lung supplied by the involved bronchi (100%, 147/147) and had a focal distribution predominantly (94.6%, 139/147). Pathologically, it correlated with bronchiolectasis, bronchiolar lumen filled by mucus and inflammatory exudates, wall thickening with inflammatory cells infiltration.

CONCLUSIONS

TIB pattern is commonly detected in central lung squamous cell carcinoma on thoracic CT scan. It usually has a localized distribution with a predominant associated CT finding of obstructive bronchial mucoid impaction. This pattern corresponds to the mucoid impaction of bronchioles and bronchiolitis pathologically. A full understanding of TIB pattern in central lung cancer can be useful in preventing diagnostic errors.

Clinicoradiologic evidence of pulmonary lymphatic spread in adult patients with tuberculosis

OBJECTIVE

The purpose of this study is to evaluate the prevalence and clinicoradiologic characteristics of pulmonary tuberculosis with lymphatic involvement.

MATERIALS AND METHODS

A total of 126 adults with active tuberculosis who underwent CT were enrolled. A retrospective investigation of CT images focused on the presence of perilymphatic micronodules, as well as other CT features of active tuberculosis. We selected two groups of patients with micronodules according to distribution (perilymphatic vs centrilobular). We compared clinical and CT findings between the two groups.

RESULTS

Fifteen patients were excluded because of coexisting pulmonary disease. Among 111 patients, the prevalence of perilymphatic micronodules, galaxy or cluster signs, and interlobular septal thickening was 64 (58%), 18 (16%), and 30 (27%), respectively. Of 106 patients with micronodules, 37 and 40 were classified into the perilymphatic and centrilobular groups, respectively. Compared with the centrilobular group, the perilymphatic group had statistically significantly lower frequencies of positive acid-fast bacilli smears (32% vs 70%), consolidation (70% vs 98%), and cavitation (30% vs 60%). However, frequencies of interlobular septal thickening (41% vs 18%), galaxy or cluster signs (30% vs 0%), and pleural effusion (43% vs 20%) were statistically significantly higher in the perilymphatic group.

CONCLUSION

CT findings representing pulmonary perilymphatic involvement are relatively common in adults with tuberculosis. These findings may represent lymphatic spread of tuberculosis and provide an explanation for the unusual CT features of pulmonary tuberculosis mimicking sarcoidosis and the low detection of Mycobacterium tuberculosis in patients with micronodules.

Multidetector CT of pulmonary cavitation: filling in the holes

Pulmonary cavitation causes significant morbidity and mortality. Early diagnosis of the presence and aetiology of a cavity is therefore crucial in order to avoid further demise in both the localized pulmonary and systemic disorders that may manifest with pulmonary cavity formation. Multidetector CT has become the principal diagnostic technique for detecting pulmonary cavitation and its complications. This review provides an overview of the aetiologies and their imaging findings using this technique. Combining a literature review with case illustration, a synopsis of the different imaging features and constellations is provided, which may suggest a particular cause and aid the differentiation from diseases with similar findings.

Radiologic and laboratory differences in patients with tuberculous and parapneumonic pleural effusions showing non-lymphocytic predominance and high adenosine deaminase levels

PURPOSE

Tuberculous pleural effusion (TPE) is characterized by lymphocytic predominance and high adenosine deaminase (ADA) levels. However, TPEs sometimes present non-lymphocytic predominance, and parapneumonic effusion (PPE) often exceeds the cutoff value of ADA for TPE. Thus, the differential diagnosis of cases with pleural fluid (PF) showing non-lymphocytic predominance and high ADA levels is challenging. However, limited data concerning the clinical differences in these patients are available.

METHODS

A retrospective study was conducted on TPE and PPE patients with PF showing non-lymphocytic predominance and ADA levels ≥40 U/L in 2009-2013 in a South Korean tertiary referral hospital. The clinical, laboratory, and computed tomography (CT) findings between the groups were analyzed using multivariate logistic regression to develop a prediction model with independent factors for TPE.

RESULTS

Among 353 patients with TPE, 24 (6.8 %) showed PF with non-lymphocytic predominance and ADA levels of ≥40 U/L. Twenty-eight PPE patients who presented PF findings comparable with those of TPE patients were included in the control group. In the final analysis, PF ADA levels >58 U/L and nodular lung lesions on CT were independent positive predictors, while loculated effusion was an independent negative predictor for TPE. Using the prediction model, a score ≥ +3 provided a sensitivity of 88 %, specificity of 93 %, positive predictive value of 91 %, and negative predictive value of 90 % for TPE.

CONCLUSION

PF ADA levels, nodular lung lesions, and loculated pleural effusion may help differentiate TPE from PPE in patients with PF showing non-lymphocytic predominance and ADA levels ≥40 U/L.

Mycobacterium tuberculosis dysregulates MMP/TIMP balance to drive rapid cavitation and unrestrained bacterial proliferation

Active tuberculosis (TB) often presents with advanced pulmonary disease, including irreversible lung damage and cavities. Cavitary pathology contributes to antibiotic failure, transmission, morbidity and mortality. Matrix metalloproteinases (MMPs), in particular MMP-1, are implicated in TB pathogenesis. We explored the mechanisms relating MMP/TIMP imbalance to cavity formation in a modified rabbit model of cavitary TB. Our model resulted in consistent progression of consolidation to human-like cavities (100% by day 28), with resultant bacillary burdens (>10(7) CFU/g) far greater than those found in matched granulomatous tissue (10(5) CFU/g). Using a novel, breath-hold computed tomography (CT) scanning and image analysis protocol, we showed that cavities developed rapidly from areas of densely consolidated tissue. Radiological change correlated with a decrease in functional lung tissue, as estimated by changes in lung density during controlled pulmonary expansion (R(2)  = 0.6356, p < 0.0001). We demonstrated that the expression of interstitial collagenase (MMP-1) was specifically greater in cavitary compared to granulomatous lesions (p < 0.01), and that TIMP-3 significantly decreased at the cavity surface. Our findings demonstrated that an MMP-1/TIMP imbalance is associated with the progression of consolidated regions to cavities containing very high bacterial burdens. Our model provided mechanistic insight, correlating with human disease at the pathological, microbiological and molecular levels. It also provided a strategy to investigate therapeutics in the context of complex TB pathology. We used these findings to predict a MMP/TIMP balance in active TB and confirmed this in human plasma, revealing the potential of MMP/TIMP levels as key components of a diagnostic matrix aimed at distinguishing active from latent TB (PPV = 92.9%, 95% CI 66.1-99.8%, NPV = 85.6%; 95% CI 77.0-91.9%).

High Resolution Computed Tomography Lung Spectrum in Symptomatic Adult HIV-Positive Patients in South-East Asian Nation

BACKGROUND

Pulmonary infections remain a leading cause of morbidity and mortality and one of the most frequent causes of hospital admission in HIV infected people worldwide. HRCT may be useful in the evaluation of patients with suspected pulmonary disease. The aim of given study was to determine the High Resolution Computed Tomography spectrum of lung parenchymal and interstitial imaging findings in HIV infected patients presented with chest symptoms.

MATERIALS AND METHODS

This study was conducted in a tertiary health care centre, New Delhi, India. The study consisted of 45 patients. A thorough clinical history of all the HIV positive patients presenting with suspicion of pulmonary disease was taken. General physical and respiratory system examination of all patients was done. HRCT scans of the chest were done in all the cases taken in the study.

RESULTS

Maximum number of patients was in age group 31-40 years (24 cases). Out of 45 patients included in our study, 32 (71%) were male and 13 (29%) were female. In our series of 45 patients, 62.2% of patients were diagnosed as having pulmonary tuberculosis, followed by bacterial infection in 20% cases and Pneumocystis jiroveci pneumonia (PJP) in 8.9% patients, while 8.9% of the study did not reveal any significant abnormality. Maximum number (22/28) of patients with pulmonary tuberculosis were indentified to have nodular opacities. The most common HRCT finding in bacterial infection was lobar consolidation. The most common HRCT finding in patients with PCP was diffuse ground glass opacities in mosaic pattern of distribution.

CONCLUSION

HRCT is a highly sensitive tool for detecting lung parenchymal and interstitial lesions and allows better characterization of the lesions. HRCT findings should always be correlated with clinical findings, CD4 counts and other available investigations before arriving at a diagnosis or differential diagnosis.

Challenges in endobronchial tuberculosis: from diagnosis to management

Despite the rapid advancement in diagnostic and therapeutic modalities, endobronchial tuberculosis (EBTB), defined as tuberculous infection of the tracheobronchial tree, continues to remain challenging for clinicians. Nonspecific respiratory symptoms along with normal chest radiograph in 10–20% of cases may be alleged for the diagnostic delay. Variable diagnostic yield with sputum microscopy might further compound the problem. In such cases, high resolution computed tomography (HRCT) works as a more sensitive tool and demonstrates involvement of tracheobronchial tree described classically as “tree-in-bud” appearance. Bronchoscopic biopsy is considered the most reliable method for confirmation of the diagnosis with 30% to 84% positivity in different series. Evolution of the disease is also unpredictable with frequent progression to bronchostenosis, therefore requiring regular follow-up and early intervention to halt the natural course. This review article elaborates various aspects of the disease with specific focus on diagnostic dilemma and recent advances in interventional bronchoscopy. In addition, this discussion evokes optimism for further research and introduction of innovative therapeutic modalities.