High resolution computed tomographic findings in pulmonary tuberculosis

High resolution computed tomography findings in smear-negative pulmonary tuberculosis patients according to their culture status

OBJECTIVE

The aim of this study was to assess the clinical features and high resolution computed tomography (HRCT) findings in smear-negative pulmonary tuberculosis (PTB) and to evaluate the correlation between these parameters and the culture results.

METHODS

We retrospectively studied 78 active smear-negative PTB patients. They were divided into two groups according to their culture results. The HRCT findings and clinical features at the beginning of the antituberculosis treatment were reviewed.

RESULTS

The mean age was 22.48±3.18 years. Micronodules (87%), large nodules (63%) and centrilobular nodules (62%) were the most common HRCT findings. HRCT findings were observed in the right upper (72%), left upper (56%), right lower (32%), and left lower lobes (29%). Cough (37%) and chest pain (32%) were the most frequent symptoms at presentation.

CONCLUSIONS

There were no significant differences in the HRCT findings and clinical features between the two groups. Thus, in cases of smear-negative and culture-negative PTB, the patient with compatible clinical and radiological features should be considered for tuberculosis treatment.

A high-resolution computed tomography-based scoring system to differentiate the most infectious active pulmonary tuberculosis from community-acquired pneumonia in elderly and non-elderly patients

OBJECTIVE

The objective of this study was to use high-resolution computed tomography (HRCT) imaging to predict the presence of smear-positive active pulmonary tuberculosis (PTB) in elderly (at least 65 years of age) and non-elderly patients (18-65 years of age).

METHODS

Patients with active pulmonary infections seen from November 2010 through December 2011 received HRCT chest imaging, sputum smears for acid-fast bacilli and sputum cultures for Mycobacterium tuberculosis. Smear-positive PTB was defined as at least one positive sputum smear and a positive culture for M. tuberculosis. Multivariate logistic regression analyses were performed to determine the HRCT predictors of smear-positive active PTB, and a prediction score was developed on the basis of receiver operating characteristic curve analysis.

RESULTS

Of 1,255 patients included, 139 were diagnosed with smear-positive active PTB. According to ROC curve analysis, the sensitivity, specificity, positive predictive value, negative predictive value, false positive rates and false negative rates were 98.6 %, 95.8 %, 78.5 %, 99.8 %, 4.2 % and 1.4 %, respectively, for diagnosing smear-positive active PTB in elderly patients, and 100.0 %, 96.9 %, 76.5 %, 100.0 %, 3.1 % and 0.0 %, respectively, for non-elderly patients.

CONCLUSIONS

HRCT can assist in the early diagnosis of the most infectious active PTB, thereby preventing transmission and minimizing unnecessary immediate respiratory isolation.

KEY POINTS

• HRCT can assist in the early diagnosis of the infectious active PTB • HRCT imaging is useful to predict the presence of smear-positive active PTB • Predictions from the HRCT imaging are valid even before sputum smear or culture results.

Causes and imaging patterns of tree-in-bud opacities

BACKGROUND

Multiple causes for tree-in-bud (TIB) opacities have been reported. However, to our knowledge the relative frequencies of the causes have not been evaluated. The purpose of this study was to determine the relative frequency of causes of TIB opacities and identify patterns of disease associated with TIB opacities.

METHODS

Cases with TIB opacities in the radiology report in 2010 were identified by searching the Radiology Information System. Medical records and CT scan examinations were reviewed for the causes of TIB opacities. Patterns of disease associated with TIB opacities were evaluated.

RESULTS

Causes for TIB opacities were established in 166 of 406 (40.9%) cases. Respiratory infections (119 of 166, 72%) with mycobacteria (65 of 166, 39%), bacteria (44 of 166, 27%), viruses (four of 166, 3%), or multiple organisms (six of 166, 4%) were most common. Aspiration was the cause in 42 of 166 (25%). Alternating areas of normal lung with regions of small airways disease (TIB opacities, bronchiectasis) (random small airways pattern) was specific (0.92) for Mycobacterium avium complex infection. Nearly uniform distribution of bronchiectasis (widespread bronchiectasis pattern) was specific for "diseases predisposing to airway infection" (specificity 0.92), such as cystic fibrosis, primary ciliary dyskinesia, allergic bronchopulmonary aspergillosis, and immunodeficiency states. Consolidation and TIB opacities (bronchopneumonia pattern) were usually due to bacterial infection or aspiration. Dependent distribution (specificity 0.79) and esophageal abnormality (specificity 0.86) with TIB opacities were associated with aspiration. Chronicity of findings was associated with mycobacterial infection (P < .0001, sensitivity 0.96). Acuteness of findings was associated with bacterial infection (P < .001, specificity 0.87).

CONCLUSIONS

TIB opacities are most often a manifestation of infections or aspiration. Patterns of disease can provide clues to the most likely diagnosis.

Efficacy and safety of metronidazole for pulmonary multidrug-resistant tuberculosis

Pulmonary lesions from active tuberculosis patients are thought to contain persistent, nonreplicating bacilli that arise from hypoxic stress. Metronidazole, approved for anaerobic infections, has antituberculosis activity against anoxic bacilli in vitro and in some animal models and may target persistent, nonreplicating bacilli. In this double-blind, placebo-controlled trial, pulmonary multidrug-resistant tuberculosis subjects were randomly assigned to receive metronidazole (500 mg thrice daily) or placebo for 8 weeks in addition to an individualized background regimen. Outcomes were measured radiologically (change on high-resolution computed tomography [HRCT]), microbiologically (time to sputum smear and culture conversion), and clinically (status 6 months after stopping therapy). Enrollment was stopped early due to excessive peripheral neuropathies in the metronidazole arm. Among 35 randomized subjects, 31 (15 metronidazole, 16 placebo) were included in the modified intent-to-treat analysis. There were no significant differences by arm in improvement of HRCT lesions from baseline to 2 or 6 months. More subjects in the metronidazole arm converted their sputum smear (P = 0.04) and liquid culture (P = 0.04) to negative at 1 month, but these differences were lost by 2 months. Overall, 81% showed clinical success 6 months after stopping therapy, with no differences by arm. However, 8/16 (50%) of subjects in the metronidazole group and 2/17 (12%) of those in the placebo group developed peripheral neuropathy. Subjects who received metronidazole were 4.3-fold (95% confidence interval [CI], 1.1 to 17.1) more likely to develop peripheral neuropathies than subjects who received placebo. Metronidazole may have increased early sputum smear and culture conversion but was too neurotoxic to use over the longer term. Newer nitroimidazoles with both aerobic and anaerobic activity, now in clinical trials, may increase the sterilizing potency of future treatment regimens.

Bronchiectasis in active tuberculosis

BACKGROUND

Bronchiectasis in tuberculosis (TB) is usually considered chronic traction bronchiectasis associated with healed scars. However, bronchiectasis can occasionally be seen in active TB.

PURPOSE

To evaluate prevalence, appearance, and changes of bronchiectasis associated with active TB on computed tomography (CT).

MATERIAL AND METHODS

A total of 391 patients with active TB who had undergone CT scans at the time of diagnosis were included in the study. Active TB was diagnosed when the sputum or the sample obtained by bronchoalveolar lavage tested positive using an acid-fast bacillus (AFB) smear test, polymerase chain reaction (PCR) test, or an AFB culture. The CT scans were reviewed focusing on bronchiectasis within consolidations or nodules. Cases with bronchiectasis beyond the consolidation or nodules were excluded from the study to exclude pre-existing traction bronchiectasis. The prevalence and appearance (cylindrical, varicose, cystic, and presence of focal erosion) of bronchiectasis and its time-dependent changes were analyzed. In addition, the presence of the feeding bronchus sign was checked. Here, the feeding bronchus sign was defined as a CT finding where the cavity communicates with the dilated airway.

RESULTS

In 100 (25%) of the 391 patients, bronchiectasis was present within consolidations or nodules on CT. The shape of the bronchiectasis was cylindrical in all patients and focal erosions were revealed in 75 patients (75%). Nine patients had both cylindrical and varicose forms of the bronchiectasis. The feeding bronchus sign was observed in 42 patients (42%). Follow-up CT was performed on 19 of 100 patients. The bronchiectasis had progressed in 11 patients (58%), improved in four patients (21%), remained unchanged in one patient (5%), and could not be determined in the remaining three patients (16%). In nine patients, CT images prior to diagnosis were available, and in all these cases, bronchiectasis was newly developed.

CONCLUSION

Bronchiectasis can be seen within active inflammation in one-fourth of active TB on CT. In association with active inflammation, bronchiectasis is mostly cylindrical with focal erosions, occasionally accompanied by the feeding bronchus sign.

Multidrug resistant tuberculosis versus non-tuberculous mycobacterial infections: a CT-scan challenge

Introduction

Clinical, laboratory and imaging findings in patients with multidrug resistant-tuberculosis (MDR-TB) and non-tuberculosis mycobacterium (NTM) are similar, and the majority of these patients present with positive smear for Acid Fast Bacilli (ADB) and no response to first line anti-TB treatment, so sputum culture and PCR are necessary, especially in NTM.

Objective

In this study we evaluate more details of imaging findings to help earlier diagnosis of pathogens.

Materials and methods

66 patients with positive smear for AFB and no response to first line anti-TB drugs were divided into two groups by PCR and culture: MDR-TB (43 patients) and NTM (23 patients). Age, sex, history of anti-TB treatment, smoking and CT-scan findings (parenchymal, pleural and mediastinal variables) by details and lobar distribution were analyzed.

Results

Mean age of NTM patients was slightly higher (52 versus 45) and there is no significant difference in sex and smoking. In MDR-TB group, history of anti-TB treatment and evidence of chronic pulmonary disease such as calcified and fibrodestructed parenchyma, volume loss and pleural thickening were higher significantly. Cavities in MDR-TB were thick-wall in the background of consolidation, while NTM cavities were more thin-walled with adjacent satellite nodules in same segment or lobe. Prevalence of bronchiectasis was similar in both groups, while bronchiectasis in MDR-TB group was in fibrobronchiectatic background in upper lobes, and in NTM group the distribution was more uniform with slightly middle lobes predominance. Prevalence and distribution of nodular infiltrations were similar more in Tree in Buds and scattered pattern. Calcified or non-calcified lymph nodes and also pleural changes were more frequent in MDR-TB but prevalence of lymphadenopathy was mildly higher in NTM.

Conclusion

A check-list with multiple variables is helpful for differentiation between the two groups.

Predictive factors for tuberculosis in patients with a TB-PCR-negative bronchial aspirate

PURPOSE

Pulmonary tuberculosis (PTB), with a tuberculosis (TB)-polymerase chain reaction (PCR)-negative bronchial aspirate (BA), but a positive culture result is often encountered in clinical practice. However, limited data are available concerning clinical judgment in patients with suspected PTB and a TB-PCR-negative BA pending culture results. The present study aimed to identify predictors for PTB in patients with a TB-PCR-negative BA.

METHODS

A retrospective study was conducted on patients who had undergone a bronchoscopy because of suspected PTB. Clinical, laboratory, and computed tomography (CT) findings were investigated in PTB patients with TB-PCR-negative but positive culture BA results, and non-PTB patients with a radiographic lesion comparable to the former.

RESULTS

Of 250 patients screened, 31 (12 %) were diagnosed with PTB by positive culture results only. Of these 31 patients, 30 (97 %) had a lesion within one-third of the hemithorax as determined by chest radiography. In the final analysis of 30 PTB and 65 non-PTB patients with comparable radiographic lesions, a positive QuantiFERON-TB Gold In-Tube (QFT) result was independently associated with an increased risk of a positive TB culture. CT findings of consolidation were a negative predictor for PTB. Patients with a negative QFT result and consolidation had a negative predictive value of 95 % for PTB, while patients with a positive QFT result and nodular CT abnormalities without consolidation had a positive predictive value of 86 % for PTB.

CONCLUSION

The simple combination of CT findings of consolidation and QFT test results may help clinicians to refine decision-making in patients with a TB-PCR-negative BA.

Multidrug-resistant tuberculosis that required 2 years for diagnosis

Isoniazid (H) or rifampicin (R) mono-resistant disease can be treated easily and effectively with first-line drugs, while combined H and R resistance (ie, multidrug-resistant tuberculosis (MDRTB)) requires treatment with at least four agents, including a quinolone and an injectable agent. Drug-resistant Mycobacterium tuberculosis strains are reported to be extremely difficult to cultivate invitro. The authors report a case of MDRTB that required 2 years for diagnosis, and was detected only in sputum culture on solid medium. Physicians should consider MDRTB if TB is suspected but pathogens are not detected.

Pathology of post primary tuberculosis of the lung: an illustrated critical review

Post primary tuberculosis occurs in immunocompetent adults, is restricted to the lungs and accounts for 80% of all clinical cases and nearly 100% of transmission of infection. The supply of human tissues with post primary tuberculosis plummeted with the introduction of antibiotics decades before the flowering of research using molecular methods in animal models. Unfortunately, the paucity of human tissues prevented validation of the models. As a result, it is a paradigm of contemporary research that caseating granulomas are the characteristic lesion of all tuberculosis and that cavities form when they erode into bronchi. This differs from descriptions of the preantibiotic era when many investigators had access to thousands of cases. They reported that post primary tuberculosis begins as an exudative reaction: a tuberculous lipid pneumonia of foamy alveolar macrophages that undergoes caseation necrosis and fragmentation to produce cavities. Granulomas in post primary disease arise only in response to old caseous pneumonia and produce fibrosis, not cavities. We confirmed and extended these observations with study of 104 cases of untreated tuberculosis. In addition, studies of the lungs of infants and immunosuppressed adults revealed a second type of tuberculous pneumonia that seldom produces cavities. Since the concept that cavities arise from caseating granulomas was supported by studies of animals infected with Mycobacterium bovis, we investigated its pathology. We found that M. bovis does not produce post primary tuberculosis in any species. It only produces an aggressive primary tuberculosis that can develop small cavities by erosion of caseating granulomas. Consequently, a key unresolved question in the pathogenesis of tuberculosis is identification of the mechanisms by which Mycobacterium tuberculosis establish a localized safe haven in alveolar macrophages in an otherwise solidly immune host where it can develop conditions for formation of cavities and transmission to new hosts.

Pulmonary involvement in pleural tuberculosis: how often does it mean disease activity?

OBJECTIVE

To evaluate in chest X-rays and high-resolution computed tomographies of patients with pleural tuberculosis, the incidence of parenchymal and mediastinal lung lesions suggestive of active disease.

METHODS

Prospective study (2008-2009) evaluating the radiographic and tomographic abnormalities of 88 HIV-negative patients with pleural tuberculosis (unilateral effusion). The images were reviewed by 3 independent specialists, and the observed changes were classified according to previously established criteria: presence or absence of signs suggestive of disease activity, and nonspecific findings.

RESULTS

Abnormal changes were observed in chest X-rays of 22 (25%) patients and in the computed tomography of 55 (63%). Images compatible with active pulmonary tuberculosis were detected by radiography in 9 (10%) patients and by tomography in 38 (43%). Only 4 (4.5%) patients had tomography images suggestive of residual disease.

CONCLUSION

The present study demonstrates that pulmonary involvement is quite common in pleural tuberculosis. This finding is mainly observed in high-resolution computed tomography and has important epidemiological implications, since patients with pleural tuberculosis are significant sources of infection and disease dissemination.

Aspectos tomográficos da tuberculose pulmonar em pacientes adultos com AIDS

OBJETIVO: Este trabalho tem como finalidade descrever os achados tomográficos da tuberculose pulmonar em pacientes adultos com AIDS atendidos no serviço de radiologia de um hospital de referência em doenças infecciosas, procurar associações desses achados e a contagem de CD4. MATERIAIS E MÉTODOS: Foram estudados 45 pacientes por meio de tomografia computadorizada de tórax durante quatro anos. RESULTADOS: Foram encontrados linfonodomegalia mediastinal e/ou hilar em 31 (68,8%) dos casos, derrame pleural em 29 (64,4%), nódulos centrolobulares de distribuição segmentar em 26 (57,7%), consolidação em 24 (53,3%), confluência de micronódulos em 17 (37,7%), nódulos mal definidos com distribuição centrolobular em 16 (35,5%), padrão de "árvore em brotamento" em 13 (28,9%), espessamento de parede brônquica em 12 (26,6%), cavidade de parede espessa em 10 (22,2%), nódulos miliares em 9 (20%) e bronquiectasias cilíndricas em 6 (13,3%). Dos 45 pacientes, 35 (77,8%) apresentaram CD4 < 200 cel/mm³ e 10 (22,2%) apresentaram CD4 > 200 cel/mm³. CONCLUSÃO: Concluímos que neste estudo, diversamente do descrito na literatura, linfonodomegalia mediastinal e/ou hilar e consolidação foram significativamente mais frequentes em pacientes com CD4 > 200 cel/mm³. No entanto, linfonodos com centro hipodenso foram mais frequentemente observados em pacientes com severa imunodepressão, ou seja, CD4 < 200 cel/mm³.

CT patterns of nodal disease in pediatric chest tuberculosis

AIM: To highlight various patterns of nodal involvement and post treatment changes in pediatric chest tuberculosis based on contrast enhanced computed tomography (CECT) scans of chest.

METHODS: This was a retrospective study consisting of 91 patients aged less than 17 years, who attended pediatric OPD of All India Institute of Medical Sciences with clinically diagnosed tuberculosis or with chest radiographs suggestive of chest tuberculosis. These patients had an initial chest radiograph as well as CECT of the chest and follow up imaging after 6 mo, and in some cases 9 mo, of completion of anti-tubercular treatment (ATT). CECT of these patients was reviewed for the location and extent of nodal involvement along with determination of site, size, enhancement pattern and calcification.

RESULTS: Enlargement of mediastinal or hilar lymph nodes was found in 88/91 patients (96.7%), with the most common locations being paratracheal (84.1%), and subcarinal (76.1%). The most common pattern of enhancement was found to be inhomogenous. The nodes were conglomerate in 56.8% and discrete in 43.2%. In addition, perinodal fat was obscured in 84.1% of patients. In the post-treatment scan, there was 87.4% reduction in the size of the nodes. All nodes post-treatment were discrete and homogenous with perinodal fat present. Calcification was found both pre- and post-treatment, but there was an increase in incidence after treatment (41.7%). There was hence a reduction in size, change in enhancement pattern, and appearance of perinodal fat with treatment.

CONCLUSION: Tubercular nodes have varied appearance and enhancement pattern. Conglomeration and obscuration of perinodal fat suggest activity. In residual nodes decision to continue ATT requires clinical correlation.

Biosynthesis and Virulent Behavior of Lipids Produced by Mycobacterium tuberculosis: LAM and Cord Factor: An Overview

Mycobacterium tuberculosis is the causative agent of tuberculosis disease, which has developed a myriad of exceptional features contributing to its survival within the hostile environment of host cell. Unique cell wall structure with high lipid content plays an imperative role in the pathogenicity of mycobacteria. Cell wall components of MTB such as lipoarabinomannan and Trehalose dimycolate (cord factor) are virulent in nature apart from its virulence genes. Virulent effect of these factors on host cells reduces host cell immunity. LAM has been known to inhibit phagosome maturation by inhibiting the Ca²⁺/calmodulin phosphatidyl inositol-3-kinase hvps34 pathways. Moreover, TDM (Trehalose dimycolate) also inhibits fusion between phospholipid vesicles and migration of polymorphonuclear neutrophils. The objective of this paper is to understand the virulence of LAM and cord factor on host cell which might be helpful to design an effective drug against tuberculosis.

Pulmonary mycobacterial disease: diagnostic performance of low-dose digital tomosynthesis as compared with chest radiography

PURPOSE

To compare the diagnostic performance of a low-radiation-dose digital tomosynthesis (DTS) technique with that of conventional radiography in the detection of lung lesions in patients with pulmonary mycobacterial disease.

MATERIALS AND METHODS

The institutional review board approved this study, and all patients provided informed consent. In this study, 100 patients (65 study patients, 35 control patients) underwent multidetector computed tomography (CT), chest radiography, and low-dose DTS (effective doses: 3.4, 0.02, and 0.05 mSv, respectively). Two radiologists evaluated radiographs and DTS images for the presence of parenchymal lesions and the number of cavities in each patient; CT served as the reference standard. Wilcoxon signed rank and McNemar tests and κ statistics were used.

RESULTS

The accuracies of DTS and radiography in depicting mycobacterial disease were 97% and 89%, respectively, for observer 1 (P = .039) and 99% and 93%, respectively, for observer 2 (P = .031). The accuracies of DTS and radiography in depicting each lesion type were, respectively, 95% and 77% for bronchiolitis, 92% and 76% for nodules, 86% and 79% for consolidation, and 93% and 70% for cavities. Interobserver agreement with DTS (κ = 0.62-0.94) was superior to that with radiography (κ = 0.46-0.62). Of a total of 141 cavities found with CT, means of 27 (19%) cavities at chest radiography and 108 (77%) cavities at DTS (P < .01) were detected by the two observers.

CONCLUSION

DTS performed with a low-dose technique is superior to radiography for the detection of lung lesions in patients with pulmonary mycobacterial disease.

Pulmonary tuberculosis associated with the reversed halo sign on high-resolution CT

We describe the case of a 32-year-old woman with pulmonary tuberculosis in whom a high-resolution CT scan demonstrated the reversed halo sign. The diagnosis of tuberculosis was made by lung biopsy and the detection of acid-fast bacilli in the sputum smear and culture. Follow-up assessment revealed a significant improvement in the lesions.

Utility of high-resolution computed tomography for predicting risk of sputum smear-negative pulmonary tuberculosis

BACKGROUND

To diagnose sputum smear-negative pulmonary tuberculosis (PTB) is difficult and the ability of high-resolution computed tomography (HRCT) for diagnosing PTB has remained unclear in the sputum smear-negative setting. We retrospectively investigated whether or not this imaging modality can predict risk for sputum smear-negative PTB.

METHODS

We used HRCT to examine the findings of 116 patients with suspected PTB despite negative sputum smears for acid-fast bacilli (AFB). We investigated their clinical features and HRCT-findings to predict the risk for PTB by multivariate analysis and a combination of HRCT findings by stepwise regression analysis. We then designed provisional HRCT diagnostic criteria based on these results to rank the risk of PTB and blinded observers assessed the validity and reliability of these criteria.

RESULTS

A positive tuberculin skin test alone among clinical laboratory findings was significantly associated with an increase of risk of PTB. Multivariate regression analysis showed that large nodules, tree-in-bud appearance, lobular consolidation and the main lesion being located in S1, S2, and S6 were significantly associated with an increased risk of PTB. Stepwise regression analysis showed that coexistence of the above 4 factors was most significantly associated with an increase in the risk for PTB. Ranking of the results using our HRCT diagnostic criteria by blinded observers revealed good utility and agreement for predicting PTB risk.

CONCLUSIONS

Even in the sputum smear-negative setting, HRCT can predict the risk of PTB with good reproducibility and can select patients having a high probability of PTB.

Padrões tomográficos das doenças intersticiais pulmonares difusas com correlação clínica e patológica

A tomografia de alta resolução (TCAR) é a técnica de imagem radiológica que reflete mais de perto as alterações da estrutura pulmonar. Os vários achados tomográficos podem ser combinados para formar padrões típicos. Estes, conjuntamente com a distribuição anatômica dos achados, e com os dados clínicos, podem estreitar o diagnóstico das doenças intersticiais pulmonares difusas, e em vários casos sugerir o diagnóstico correto com alto grau de acurácia. Os padrões mais comuns das doenças intersticiais pulmonares difusas na TCAR são o nodular, linear e reticular, lesões císticas, opacidades em vidro fosco e consolidações. Este artigo revisa as correlações entre os padrões tomográficos na TCAR e os achados patológicos e resume as causas mais comuns e os métodos de investigação para se atingir um diagnóstico nas doenças pulmonares crônicas difusas mais comuns.

High resolution chest CT in patients with pulmonary tuberculosis: Characteristic findings before and after antituberculous therapy

OBJECTIVE

The purpose of this study was (a) to describe HRCT findings for pulmonary tuberculosis before and after treatment, and (b) to evaluate the possible use of HRCT to assess disease activity.

PATIENTS AND METHODS

We prospectively studied 52 patients with newly diagnosed pulmonary tuberculosis that was proven bacteriologically. HRCT scans were performed before and after treatment.

RESULTS

Micronodules, nodules, tree-in-bud appearance, consolidation, and cavities were the most common HRCT findings seen in active pulmonary tuberculosis. The disappearance of tree-in-bud appearance, pleural effusion and the presence of fibrotic change appear to be indications of the effectiveness of treatment. HRCT can differentiate old fibrotic lesions from newly active tuberculous lesions.

CONCLUSIONS

HRCT may be helpful in the diagnosis of pulmonary tuberculosis and may be useful in the assessment of the efficacy of anti-tuberculous treatment.

Biomarkers of treatment response in clinical trials of novel antituberculosis agents

Global initiatives have been launched to develop improved tuberculosis chemotherapy. New drugs and potential treatment-shortening regimens require careful assessment in clinical trials, but existing markers of treatment outcome-clinical cure and relapse-require prolonged follow-up of patients. There is, therefore, a need to find alternative biomarkers or surrogate endpoints predictive of response. Effective treatment requires drugs with sterilising activity to produce clinical cure without relapse, and thus a useful biomarker for a drug under trial must predict the likelihood of relapse. We explore the strengths and weaknesses of existing biomarkers, which assess either host response or mycobacterial load. Change in mycobacterial burden is likely to be the best indicator of treatment outcome, but the optimum study techniques remain undefined. Finally, we propose methods to assess candidate markers, and how these candidate markers could be implemented in future clinical trials.

[Tuberculosis in the autopsy. Clinical and pathological study: an analysis of 92 cases of active tuberculosis found in 2,180 autopsies]

BACKGROUND AND OBJECTIVE

Tuberculosis is an infectious disease currently having great importance in the daily clinical practice in Spain. Some cases of active tuberculosis are not identified until after the patient had died and an autopsy has been performed. This study has analyzed the clinical and pathological characteristics of patients diagnosed with active tuberculosis in the autopsy.

MATERIAL AND METHOD

We reviewed all the autopsies performed in the University Hospital 12 de Octubre of Madrid between 1974 and 2002. The autopsy reports and clinical records were examined in those cases in which active tuberculosis was found.

RESULTS

We found 92 cases of active tuberculosis, 57% corresponding to men. Mean age of this group was 64 years. A total of 20% of the patients died within 48 hours after admission. Predisposing factors were identified in 90% of the cases. Dyspnea (24% of cases) and wasting syndrome (23%) were the main symptoms that motivated patients to request medical attention. Up to 30% of cases had normal chest X-ray. Tuberculosis was suspected in only 46% of patients before death. Principal cause of death was tuberculosis in 61% of patients, 52% of patients had pulmonary tuberculosis, 28% suffered from miliary tuberculosis and 20% from extra-pulmonary tuberculosis. The lungs were the most frequently affected organ. Epithelioid granulomas were found in all patients.

CONCLUSIONS

Tuberculosis is an uncommon finding in the autopsy as the cause of death. The presence of unspecific symptomatology, insufficient cost-effectiveness of the diagnostic tests and precocious death, are identified as the most frequent causes of undiagnosed tuberculosis.

Radiologische Diagnostik der Lungentuberkulose

The radiologic knowledge of tuberculosis-associated lung disease is an essential tool in the clinical diagnosis of tuberculosis. Chest radiography is the primary imaging method, but the importance of CT is still increasing, as CT is more sensitive in the detection of cavitation, of hilar and mediastinal lymphadenopathie, of endobronchial spread and of complications in the course of the disease. In addition, CT has been proven as a valuable technique in the assessment of tuberculosis activity, especially in patients where M. tuberculosis has not been detected in the sputum or in patients with multidrug-resistant tuberculosis. Depending on the immune status of the patient, the morphologic spectrum of tuberculosis is quite variable. Early diagnosis of tuberculosis is essential to prevent further spread of the disease.

Pathology of postprimary tuberculosis in humans and mice: contradiction of long-held beliefs

Tuberculosis remains one of the world's leading infectious causes of death. Approximately 80% of all disease is due to postprimary (secondary) tuberculosis in the lung. Unfortunately, tissues of developing lesions are seldom available and there are no recognized models of postprimary tuberculosis. In the preantibiotic era when tissues were more abundant, several investigators described early postprimary tuberculosis as a lipid pneumonia quite different from the caseating granulomas commonly described today. We used histopathologic, immunohistochemical and acid fast stains to examine tissues from several people with untreated primary and postprimary tuberculosis and compared the findings with those of mice with reactivation tuberculosis. The results confirmed that developing postprimary tuberculosis begins as a lipid pneumonia accompanied by bronchial obstruction in which infection is restricted to foamy alveolar macrophages. Cavities result from a combination of caseation of tuberculous pneumonia and microvascular occlusion characteristic of delayed type hypersensitivity (DTH). Reactivation tuberculosis in the mouse begins as a similar tuberculous lipid pneumonia with bronchial obstruction and evidence for participation of DTH. Developing necrosis in both species is associated with localization of organisms within lipid droplets. These results suggest that reactivation tuberculosis in mice is a valuable model of developing human postprimary tuberculosis.

Radiological findings of mycobacterial diseases

The diagnosis and treatment of mycobacterial diseases are very important clinical issues. Among mycobacterial diseases, pulmonary tuberculosis remains an important cause of morbidity and mortality throughout the world. Pulmonary tuberculosis demonstrates a variety of clinical and radiological features. In addition, the prevalence of Mycobacterium avium complex (MAC) has increased, especially in elderly women without underlying diseases. Clinically, there is a significant difference between tuberculosis and atypical mycobacterium infection in terms of the infection control measures adopted and the choice of treatment. Therefore, it is very important to know the characteristic radiological findings of mycobacterial diseases. In the present review, key radiological points for diagnosing mycobacterial diseases are discussed.

Tree-in-bud pattern at thin-section CT of the lungs: radiologic-pathologic overview

The tree-in-bud pattern is commonly seen at thin-section computed tomography (CT) of the lungs. It consists of small centrilobular nodules of soft-tissue attenuation connected to multiple branching linear structures of similar caliber that originate from a single stalk. Originally reported in cases of endobronchial spread of Mycobacterium tuberculosis, this pattern is now recognized as a CT manifestation of many diverse entities. These entities include peripheral airway diseases such as infection (bacterial, fungal, viral, or parasitic), congenital disorders, idiopathic disorders (obliterative bronchiolitis, panbronchiolitis), aspiration or inhalation of foreign substances, immunologic disorders, and connective tissue disorders and peripheral pulmonary vascular diseases such as neoplastic pulmonary emboli. Knowledge of the many causes of this pattern can be useful in preventing diagnostic errors. In addition, although the causes of this pattern are frequently indistinguishable at radiologic evaluation, the presence of additional radiologic findings, along with the history and clinical presentation, can often be useful in suggesting the appropriate diagnosis.

Specific high-resolution computed tomography findings associated with sputum smear-positive pulmonary tuberculosis

OBJECTIVES

This study aimed to evaluate whether high-resolution computed tomography (HRCT) could predict the results of a sputum smear in patients with active pulmonary tuberculosis.

METHODS

Forty-eight patients with active pulmonary tuberculosis were divided into 2 groups: sputum smear-positive (n = 25) and -negative (n = 23). The HRCT findings were retrospectively reviewed, focusing on the presence or absence of features previously reported to indicate active pulmonary tuberculosis, including ground-glass opacity, cavitation, centrilobular opacity, and air space consolidation.

RESULTS

Although air space consolidation was the least common feature overall, it occurred significantly more frequently in the smear-positive group than in the smear-negative group. This feature also had the highest specificity and positive predictive value. Cavitation and ground-glass opacity also occurred significantly more frequently in the smear-positive group. The frequency of centrilobular opacity did not differ between the 2 groups.

CONCLUSIONS

The present study suggested that the HRCT findings of air space consolidation, cavitation, and ground-glass opacity are significantly associated with smear-positive pulmonary tuberculosis.

The Roles of HRCT and Clinical Parameters in Assessing Activity of Suspected Smear Negative Pulmonary Tuberculosis

BACKGROUND

Smear-negative pulmonary tuberculosis (SNPTB) constitutes a major problem in countries with a moderate or high TB prevalence. The value of high-resolution computed tomography (HRCT), chest x-ray and other clinical findings in determining activity of SNPTB were investigated.

METHODS

The study population consisted of 85 patients with suspected SNPTB, of whom 52 were confirmed as active pulmonary TB according to either culture positivity for Mycobacteriun tuberculosis or demonstration of caseous granulomatous inflammation. The remaining 33 patients accepted inactive TB sequel.

RESULTS

Cough and expectoration were significantly frequent in inactive group whereas chest pain was detected higher in active patients. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of HRCT in detecting disease activity were 88, 88, 92, 83 and 88%, respectively. Centrilobular nodules, other non-calcified nodules, consolidation and cavity were significantly higher on HRCT in active group. Chest x-ray scores that were graded 1 to 3 showed a linear trend for the disease activity.

CONCLUSIONS

HRCT has good diagnostic value in detecting activity of SNPTB, and some clinical findings may help in predicting the activity.

Relationship between CT findings of pulmonary tuberculosis and the number of acid-fast bacilli on sputum smears

PURPOSE

To investigate the relationship between computed tomography (CT) findings in patients with active pulmonary tuberculosis (PTB) and the number of acid-fast bacilli (AFB) on sputum smears.

METHODS

We reviewed CT scans of 173 patients with active PTB. The patients were divided into groups according to the number of AFB on sputum smears as follows: A, negative (n = 40); B, doubtful (n = 21); C, + (n = 34); and D, ++ or greater (n = 78). The presence or absence and the number of lobes that included micronodules, nodules, consolidation and cavitation, the number of cavities and the maximum diameter of the cavity lumen were noted.

RESULTS

The frequency of micronodules and nodules did not significantly differ among the four groups. In contrast, the frequency of consolidation and cavitation increased with the number of AFB (P < .0001). Differences in the number of lobes involving micronodules, nodules, consolidation and cavitation were significant between Group D and the other groups (P < .0001), but not between Groups A or B and C. The number and maximum size of cavities significantly differed between Group D and the other groups (P < .0001).

CONCLUSIONS

CT findings correlated with the number of AFB in sputum smears to some extent. However, CT findings do not reliably discriminate between smear-negative patients and those with very few AFB excreting smear-positive patients.

Radiological manifestations of pulmonary tuberculosis

Pulmonary tuberculosis (TB) is a common worldwide lung infection. The radiological features show considerable variation, but in most cases they are characteristic enough to suggest the diagnosis. Classically, tuberculosis is divided into primary, common in childhood, and postprimary, usually presenting in adults. The most characteristic radiological feature in primary tuberculosis is lymphadenopathy. On enhanced CT, hilar and mediastinal nodes with a central hypodense area suggest the diagnosis. Cavitation is the hallmark of postprimary tuberculosis and appears in around half of patients. Patchy, poorly defined consolidation in the apical and posterior segments of the upper lobes, and in the superior segment of the lower lobe is also commonly observed. Several complications are associated with tuberculous infection, such as hematogenous dissemination (miliary tuberculosis) or extension to the pleura, resulting in pleural effusion. Late complications of tuberculosis comprise a heterogeneous group of processes including tuberculoma, bronchial stenosis bronchiectasis, broncholithiasis, aspergilloma, bronchoesophageal fistula and fibrosing mediastinitis. Radiology provides essential information for the management and follow up of these patients and is extremely valuable for monitoring complications.

Pulmonary tuberculosis: tomographic evaluation in the active and post-treatment phases

CONTEXT

Adequate knowledge of images consistent with tuberculosis activity is an important resource for tuberculosis diagnosis and treatment.

OBJECTIVE

To evaluate the structural alterations caused by tuberculosis in the pulmonary parenchyma, both during the active phase of the disease and after the end of the treatment, through computerized tomography of the thorax.

TYPE OF STUDY

Prospective study.

SETTING

Pulmonary Division, Hospital das Clínicas, Faculdade de Medicina da Universidade de São Paulo.

PARTICIPANTS

20 patients, carriers of pulmonary tuberculosis, confirmed by Mycobacterium tuberculosis culture.

PROCEDURES

Conventional tomography scans of the patients were obtained at two times: upon diagnosis and after the end of the treatment. The following were considered suggestive signs of tuberculosis activity: centrilobular nodules with segmented distribution, confluent micronodules, consolidations, thick-walled cavities, nodules, masses, thickening of the bronchial walls, tree-in-bud appearance and cylindrical bronchiectasis.

MAIN MEASUREMENTS

The presence of suggestive signs of tuberculosis activity was compared between the start and the end of treatment by means of the signs test (z).

RESULTS

All patients (20/20) presented suggestive signs of tuberculosis activity at the start of treatment. After the end of treatment, 13 patients (13/20) still presented some suggestive signs consistent with activity. A reduction in the extent of lung attack was seen post-treatment, in relation to its start (z = 10.10). This change was statistically significant (p < 0.001).

CONCLUSION

Signs suggestive of tuberculosis activity are present in the active disease and are seen via computed tomography. The extent of parenchymal attack significantly decreases following treatment. Such signs may be useful in the diagnosis of pulmonary tuberculosis.

Role of contrast-enhanced dynamic CT in the diagnosis of active tuberculoma

STUDY OBJECTIVES

To assess the role of contrast-enhanced dynamic CT in the diagnosis of active tuberculoma.

SETTING

Hospitals with an isolated ward for tuberculosis.

METHODS

Fifty-five subjects with newly diagnosed active tuberculoma and 24 subjects with inactive tuberculoma were examined and evaluated retrospectively. Six subjects with active tuberculomas and seven subjects with inactive tuberculomas were confirmed by histologic and microbiologic evaluation of resected specimens, whereas the remainder of the subjects with tuberculoma were confirmed clinically. The subjects were receiving iopamidol, 370 mg/mL IV, at a rate of 3.0 mL/s on contrast-enhanced dynamic CT. The time-attenuation curve was obtained and adapted to a gamma function. The peak height (PH), maximum attenuation subtracted by the background attenuation, relative flow (RF), and mean regional flow were used for comparison.

MEASUREMENTS AND RESULTS

In the surgically confirmed group, the PH and RF values of six subjects with active tuberculomas were significantly higher than those of the seven subjects with inactive tuberculoma (p < 0.05). Similarly, in the subjects with noninvasive diagnoses, the PH and RF values of 49 subjects with active tuberculoma were significantly higher than those of the subjects with inactive tuberculoma (mean +/- SD PH, 43.4 +/- 4.1 Hounsfield units [HU] vs 11.6 +/- 2.7 HU, p < 0.0001; RF, 0.012 +/- 0.001/s vs 0.006 +/- 0.001/s, p < 0.05). When the cutoff value was defined as mean +/- 2 SD, the sensitivity and specificity of the diagnosis for active tuberculoma were 77.1% and 96.4% in PH, and 68.5% and 88.8% in RF, respectively.

CONCLUSION

Contrast-enhanced dynamic CT is a potentially valuable tool for the diagnosis of active tuberculoma.

CT of tuberculosis and nontuberculous mycobacterial infections

Radiologic manifestations of pulmonary tuberculosis (TB) can vary according to several host factors, including prior exposure to TB, age, and underlying immune status. Although chest radiography is the mainstay in the evaluation of pulmonary TB, CT generally is required to detect fine lesions overlooked on chest radiographs, to define equivocal lesions, or to evaluate complications. High-resolution CT is useful in understanding the pathologic process of the disease and in determining disease activity in selected cases. This article describes the characteristic CT findings of various forms of pulmonary TB and nontuberculous mycobacterial infection according to immune status of the patients, and assesses the role of CT in the diagnosis and management of pulmonary TB.

Tuberculose pulmonar: achados na tomografia computadorizada de alta resolução do tórax em pacientes com doença em atividade comprovada bacteriologicamente

Objetivo: Descrever os achados em pacientes com tuberculose pulmonar em atividade na tomografia computadorizada de alta resolução e o padrão de distribuição das lesões pelo parênquima pulmonar. Casuística e método: Foram analisadas retrospectivamente as tomografias de alta resolução de 42 pacientes com diagnóstico bacteriológico de tuberculose pulmonar ou forte suspeita clínica, com posterior confirmação bacteriológica. Resultados: Os principais sinais sugestivos de atividade encontrados foram nódulos do espaço aéreo (83%), nódulos centrolobulares (74%), aspecto de árvore em brotamento (67%), cavitações (67%), espessamento das paredes brônquicas (55%), consolidações (48%), opacidade em vidro fosco (21%), e espessamento do interstício pulmonar (9%). Conclusão: A tomografia computadorizada de alta resolução do tórax pode sugerir fortemente atividade da doença, sendo particularmente útil nos pacientes com baciloscopias negativas e/ou radiografias indeterminadas, permitindo a instituição de tratamento adequado, antes mesmo do crescimento da micobactéria em meio de cultura.

Imagem em tuberculose pulmonar

A tuberculose é uma doença de alta incidência e prevalência no Brasil. Sinais sugestivos de atividade ou seqüela da tuberculose podem ser obtidos através dos métodos de imagem. Na radiografia de tórax, a tuberculose pulmonar ativa pode manifestar-se sob a forma de consolidações, cavitações, padrões intersticiais (reticulares/retículo-nodulares), linfonodomegalias hilares ou mediastinais e derrame pleural. Imagens compatíveis com doença ativa, como nódulos centrolobulares de distribuição segmentar, cavidades de paredes espessas, espessamento de parede brônquica ou bronquiolar, bronquiectasias e linfonodomegalias, podem ser observadas pela tomografia computadorizada do tórax; cavidades de paredes finas, bronquiectasias de tração e estrias são imagens sugestivas de seqüela da doença, assim como o enfisema e o aspecto em mosaico do parênquima pulmonar. A cintilografia com o citrato de gálio-67 é um método complementar útil na detecção de processos infecciosos, incluindo a tuberculose, especialmente em pacientes imunossuprimidos. Estudos de inalação e perfusão pulmonar são utilizados na avaliação pré-operatória de pacientes com seqüelas de tuberculose ou tuberculose multirresistente. A tomografia por emissão de pósitrons utilizando a deoxiglicose marcada com o flúor-18 permite a detecção do processo inflamatório que ocorre na fase ativa da tuberculose e que pode persistir, em menor intensidade, após o término do tratamento. Métodos de imagem constituem importantes recursos para o diagnóstico e acompanhamento da tuberculose pulmonar.

Radiology of pneumonia

Infection of the lower respiratory tract, acquired by way of the airways and confined to the lung parenchyma and airways, typically presents radiologically as one of three patterns: (1) focal nonsegmental or lobar pneumonia, (2) multifocal bronchopneumonia or lobular pneumonia, and (3) focal or diffuse "interstitial" pneumonia. These patterns can be useful in identifying the etiological organism in the appropriate clinical setting. To serve the purpose of this article, these patterns are used as the primary method of classification of pulmonary infections caused by different organisms. Mycobacterial and fungal pulmonary infections are reviewed separately because of their wide range of radiographic appearance that depend on the stage of the disease at presentation. This article discusses the clinical and radiographic features of the most common causes of pneumonia, primarily in the adult population of the United States.

Thoracic sequelae and complications of tuberculosis

Pulmonary tuberculosis is caused by Mycobacterium tuberculosis when droplet nuclei laden with bacilli are inhaled. In accordance with the virulence of the organism and the defenses of the host, tuberculosis can occur in the lungs and in extrapulmonary organs. A variety of sequelae and complications can occur in the pulmonary and extrapulmonary portions of the thorax in treated or untreated patients. These can be categorized as follows: (a) parenchymal lesions, which include tuberculoma, thin-walled cavity, cicatrization, end-stage lung destruction, aspergilloma, and bronchogenic carcinoma; (b) airway lesions, which include bronchiectasis, tracheobronchial stenosis, and broncholithiasis; (c) vascular lesions, which include pulmonary or bronchial arteritis and thrombosis, bronchial artery dilatation, and Rasmussen aneurysm; (d) mediastinal lesions, which include lymph node calcification and extranodal extension, esophagomediastinal or esophagobronchial fistula, constrictive pericarditis, and fibrosing mediastinitis; (e) pleural lesions, which include chronic empyema, fibrothorax, bronchopleural fistula, and pneumothorax; and (f) chest wall lesions, which include rib tuberculosis, tuberculous spondylitis, and malignancy associated with chronic empyema. These varieties of radiologic manifestations can mimic other disease entities. Therefore, recognition and understanding of the radiologic manifestations of the thoracic sequelae and complications of tuberculosis are important to facilitate diagnosis.

Mycobacterial infections: still a millennium bug--the imaging features of mycobacterial infections

Mycobacterial infection is re-emerging as a major health care concern. Although Mycobacterium tuberculosis(MTB) is still the most important pathogen, atypical mycobacterium (AMB) infections are becoming increasingly common. We present a pictorial review of the imaging features of these infections in the chest, abdomen, brain and musculoskeletal system. Imaging similarities and differences between the normal and the immunocompromised host will be highlighted.

Relationship between estimated pretest probability and accuracy of automated Mycobacterium tuberculosis assay in smear-negative pulmonary tuberculosis

BACKGROUND

The AMPLICOR assay (Roche; Branchburg, NJ), a rapid direct amplification test for Mycobacterium tuberculosis, has only been licensed for use in smear-positive respiratory specimens. However, many patients with pulmonary tuberculosis (PTB) have smear-negative disease. The clinical utility of this test in patients with smear-negative PTB is unknown.

OBJECTIVE

To evaluate the effect of pretest probability of PTB estimated by chest physicians on the accuracy of the AMPLICOR assay in patients with smear-negative PTB.

DESIGN AND METHODS

A prospective study of consecutive patients suspected of having smear-negative PTB. Two chest physicians estimated the pretest probability of active disease (high, intermediate, and low categories). Respiratory specimens were examined with radiometric broth medium cultures and with the AMPLICOR assay for M tuberculosis. The decision on a final diagnosis of PTB was blinded to the AMPLICOR results.

RESULTS

Active PTB was diagnosed in 25 of 441 patients (5.7%). The AMPLICOR assay had an overall sensitivity of 44% and a specificity of 99%. Results of the assay were negative in seven patients with culture-negative PTB. The proportions of patients in the high, intermediate, and low pretest groups were 4.5%, 19.7%, and 75.7%, respectively. The incidence of PTB for each group was 95%, 3.4%, and 0.9%, respectively. The sensitivities of the AMPLICOR assay in the three groups of patients were 47%, 33%, and 33%, respectively, while the specificities were 100%, 98%, and 99%, respectively.

CONCLUSIONS

In patients suspected of having smear-negative PTB, the following conclusions were drawn: (1) the incidence of active PTB was low; (2) pretest estimates accurately discriminated between patients with high and low risk of PTB; (3) the risk of PTB was overestimated in the intermediate group; and (4) the utility of the AMPLICOR assay in the intermediate-risk group may be limited by the overestimation of disease prevalence and low test sensitivity. Further studies are needed on the role of the AMPLICOR assay in better selected patients with an intermediate risk of having smear-negative PTB.

Targeting vascular endothelial growth factor blockade: ascites and pleural effusion formation

PRIMARY PURPOSE

Formation of ascites and pleural effusion (PE) is a common problem for patients with advanced-stage cancer. These fluid accumulations cause severe symptoms such as abdominal distention, shortness of breath, cachexia, anorexia, and fatigue. Preclinical models have demonstrated that vascular endothelial growth factor (VEGF) plays a pivotal role in the accumulation of malignant PE or ascites. This study investigated whether blockade of VEGF activity would reduce biological activity of PE and ascites on endothelial cells of cancer patients.

PATIENTS AND METHODS

The activity of VEGF in PE and ascites of 58 patients (39 with PE and 19 with ascites) was measured. An endothelial cell proliferation assay with human umbilical vein endothelial cells was used to determine the biological activity of ascites and PE.

RESULTS

VEGF concentrations ranged from 67-6,245 pg/ml. A significantly higher concentration of VEGF was detected in the ascites and PE of patients with cancer (median, 1,290 pg/ml) than in patients with nonmalignant disease (median, 250 pg/ml; p = 0.02). Of the 58 PE and ascites samples, 41 were biologically active, based on a two- to fourfold stimulation of endothelial cell proliferation in 72 hours. VEGF concentrations were significantly higher in the biologically active samples compared with the 17 nonactive samples (2,056 pg/ml versus 771 pg/ml; p = 0.02). Coincubation of the samples with either a neutralizing polyclonal antibody against VEGF or SU5416, a small molecule inhibitor of the VEGF receptor Flk-1/KDR, inhibited endothelial cell proliferation by 66% and 100%, respectively. The inhibition caused by the antibody and that caused by SU5416 correlated significantly (r = 0.8, p<0.001).

CONCLUSION

We conclude that malignant ascites and PE contain high levels of biologically active VEGF. This study strongly supports the hypothesis that blockade of VEGF, such as that afforded by SU5416, may benefit cancer patients with recurrent ascites or PE formation.

Transient radiographic progression during initial treatment of pulmonary tuberculosis: CT findings

PURPOSE

A study was undertaken to describe the thin-section CT features of transient radiographic progression during initial treatment of active pulmonary tuberculosis.

METHOD

The CT scans of 13 patients who developed transient radiographic progression during initial treatment of pulmonary tuberculosis were evaluated and compared with those of 10 patients with true progression of pulmonary tuberculosis. Two patients underwent transbronchial lung biopsy for pathologic evaluation of new lesion.

RESULTS

Eight patients had increased opacity at the site of their original lesion, whereas five had new opacities elsewhere: ipsilateral (n = 3) or contralateral (n = 1) to the original lesion or both (n = 1). Relatively extensive areas of ground-glass attenuation were concomitantly depicted in three of the eight patients with progression in the area of the original lesion. In those with progression ipsilateral or contralateral to the lesion, the character of the new lesions was ground-glass opacity and/or consolidation mainly in the subpleural region. Transbronchial lung biopsy specimens obtained from two patients showed intraluminal organizing exudates and thickened alveolar septa with lymphocyte infiltration, whereas the dominant CT findings of true progression of pulmonary tuberculosis were nodules (n = 8) or centrilobular nodules (n = 7).

CONCLUSION

Thin-section CT may be useful to differentiate transient radiographic progression from true progression of pulmonary tuberculosis.