Hypothesis on the evolution of cavitary lesions in nontuberculous mycobacterial pulmonary infection: thin-section CT and histopathologic correlation

OBJECTIVE: The objectives of our study were to evaluate the thin-section CT findings of the cavitary form of nontuberculous mycobacterial pulmonary infection and correlate these imaging findings with the histopathologic findings concerning the development of bronchiectasis and of centrilobular nodules and cavitary lesions. MATERIALS AND METHODS: We retrospectively reviewed thin-section CT scans (2.5-mm collimation, both axial and coronal reformation images) of 24 cases (male-female ratio, 13:11; mean age, 61 years; age range, 43-82 years) of the cavitary form of culture-proven Mycobacterium avium-intracellulare complex pulmonary infection including two cases with lobectomy specimens. Any changes in CT findings detected on the follow-up CT scans that were available for seven patients (follow-up interval, 6-24 months; mean, 12 months) were also assessed. RESULTS: Thin-section CT findings were bronchiectasis (24/24 patients, 100%), a patent bronchus running into a cavitary lesion (the "feeding bronchus" appearance) (18/24, 75%), nodules less than 10 mm (17/24, 71%), centrilobular nodules (17/24, 71%), nodules of 10-30 mm (13/24, 54%), peribronchial nodules (8/24, 33%), lobular consolidation (6/24, 25%), bronchial wall thickening (4/24, 17%), and consolidation (2/24, 8%). Two lobectomy specimens showed large cavitary consolidations with the feeding bronchus appearance on pathologic specimens. In two patients, small peribronchial nodules had changed into cavitary nodules with the feeding bronchus appearance on follow-up CT, which represented inflamed focal cystic bronchiectasis. CONCLUSION: In the cavitary form of M. avium-intracellulare complex pulmonary infection, the feeding bronchus appearance is another very frequent thin-section CT finding. This appearance may suggest that peribronchial nodules of M. avium-intracellulare complex infection evolve into inflamed focal cystic bronchiectasis manifesting as cavitary lesions.     

CT features of pulmonary nontuberculous mycobacterial infection: effects of underlying pulmonary disease

The CT findings of 50 cases of pulmonary nontuberculous mycobacterial infection (NMI) were evaluated by dividing patients into two clinical groups: group 1, with no history of pulmonary disease (n=34), and group 2, with underlying pulmonary disease (n=16), and observing serial CT images. Bronchiectasis, irregular opacity, and small nodule were common findings and were concomitantly seen in 80% of cases in both groups. In group 1, small nodule, peripheral bronchiectasis, and irregular opacity with bronchiectasis in the middle lobes were common findings. On the other hand, irregular opacity with cavity in the upper lobes was a common CT finding in group 2. Irregular opacity was a more frequent finding of NMI than previously reported and might be seen as the sole manifestation of NMI, especially in group 2 patients. Serial CT studies showed frequent changes in small nodule and irregular opacity. Irregular opacity with cavity tended to progress, whereas irregular opacity without bronchiectasis or cavity may or may not improve.     

Nontuberculous mycobacterial pulmonary infection in immunocompetent patients: comparison of thin-section CT and histopathologic findings

PURPOSE: To identify and describe the thin-section computed tomographic (CT) findings of nontuberculous mycobacterial (NTM) pulmonary infection in immunocompetent patients and to compare these findings with histopathologic findings. MATERIALS AND METHODS: Between April 2002 and March 2003, the thin-section chest CT findings in and histopathologic lung tissue specimens from 22 patients who fulfilled the American Thoracic Society diagnostic criteria for NTM pulmonary infection were retrospectively reviewed. The lung lesion patterns (ie, small nodules, branching centrilobular nodules [ie, tree-in-bud pattern], consolidation, cavities, bronchiectasis, and volume loss) seen at CT at the sites of transbronchial lung biopsy (n = 22) or lobectomy (n = 1) were compared with the histopathologic findings. RESULTS: Thirteen of the 22 patients were found to have Mycobacterium abscessus pulmonary infection; seven, to have Mycobacterium avium-intracellulare complex infection; and two, to have Mycobacterium fortuitum infection. Regardless of the specific infective mycobacterial species, bilateral small nodules (in 22 [100%] lung locations), cylindric bronchiectasis (in 20 [91%] locations), and branching centrilobular nodular lesions (in 17 [77%] locations) were the most common CT findings seen at the biopsy sites. All of the transbronchial lung biopsy specimens showed a thickened bronchiolar wall and bronchiolar and peribronchiolar inflammation at histopathologic analysis. Dilated bronchioles were identified in 19 (86%) patients, and epithelioid granulomas with or without caseation were seen in seven (32%). CONCLUSION: Regardless of the specific infective mycobacterial species, the most common thin-section CT findings of NTM pulmonary infection are bilateral small nodules, cylindric bronchiectasis, and branching centrilobular nodules. These findings correspond histopathologically to bronchiolectasis and bronchiolar and peribronchiolar inflammation with or without granuloma formation.     

Drug-sensitive tuberculosis, multidrug-resistant tuberculosis, and nontuberculous mycobacterial pulmonary disease in nonAIDS adults: comparisons of thin-section CT findings

The aim of this work was to compare thin-section CT (TSCT) findings of drug-sensitive (DS) tuberculosis (TB), multidrug-resistant (MDR) TB, and nontuberculous mycobacterial (NTM) pulmonary disease in nonAIDS adults. During 2003, 216 (113 DS TB, 35 MDR TB, and 68 NTM) patients with smear-positive sputum for acid-fast bacilli (AFB), and who were subsequently confirmed to have mycobacterial pulmonary disease, underwent thoracic TSCT. The frequency of lung lesion patterns on TSCT and patients' demographic data were compared. The commonest TSCT findings were tree-in-bud opacities and nodules. On a per-person basis, significant differences were found in the frequency of multiple cavities and bronchiectasis (P < 0.001, chi-square test and multiple logistic regression analysis). Multiple cavities were more frequent in MDR TB than in the other two groups and extensive bronchiectasis in NTM disease (multiple logistic regression analysis). Patients with MDR TB were younger than those with DS TB or NTM disease (P < 0.001, multiple logistic regression analysis). Previous tuberculosis treatment history was significantly more frequent in patients with MDR TB or NTM disease (P < 0.001, chi-square test and multiple logistic regression analysis). In patients with positive sputum AFB, multiple cavities, young age, and previous tuberculosis treatment history imply MDR TB, whereas extensive bronchiectasis, old age, and previous tuberculosis treatment history NTM disease.     

Radiographic and CT findings of nontuberculous mycobacterial pulmonary infection caused by Mycobacterium abscessus

OBJECTIVE: The purpose of our study was to describe the radiographic and CT findings in patients with pulmonary infections caused by Mycobacterium abscessus, one of the more common rapidly growing nontuberculous mycobacteria that cause lung disease. CONCLUSION: The main radiologic and CT manifestations of M. abscessus lung infection are bilateral small nodular opacities, bronchiectasis, and cavity formation.     

The many faces of pulmonary nontuberculous mycobacterial infection

OBJECTIVE: The purpose of this article is to review clinical and radiologic manifestations of pulmonary nontuberculous mycobacterial infection. CONCLUSION: Common and well-recognized patterns of infection include cavitary and bronchiectatic disease and infection in AIDS patients. Less common or well-recognized manifestations include nodules or masses mimicking malignancy, hypersensitivity pneumonitis, and others. Definitive diagnosis can be difficult and patterns may overlap. Timely diagnosis requires a high index of suspicion and knowledge of the spectrum of clinical and radiologic features.     

Follicular bronchiolitis: thin-section CT and histologic findings.

PURPOSE: To evaluate the thin-section computed tomographic (CT) findings of follicular bronchiolitis and compare them with the histologic findings. MATERIALS AND METHODS: Thin-section CT scans obtained in 12 patients (age range, 24-77 years; mean age, 47 years) with follicular bronchiolitis proved at open lung biopsy were reviewed by two observers. Underlying conditions included rheumatoid arthritis (n = 8), mixed collagen vascular disorders (n = 2), autoimmune disorder (n = 1), and acquired immunodeficiency syndrome (n = 1). All patients had thin-section CT scans (1.0-1.5-mm collimation, 11 patients; 3.0-mm collimation, one patient; high-spatial-frequency reconstruction algorithm) obtained at 10-mm intervals through the chest. RESULTS: The main CT findings included bilateral centrilobular (n = 12) and peribronchial (n = 5) nodules. All 12 patients had nodules smaller than 3 mm in diameter; six patients also had nodules 3-12 mm in diameter. Areas of ground-glass opacity were present in nine (75%) patients. Histologically, all patients had lymphoid hyperplasia along the bronchioles; eight had peribronchiolar lymphocytic infiltration. CONCLUSION: The cardinal CT feature of follicular bronchiolitis consists of small centrilobular nodules variably associated with peribronchial nodules and areas of ground-glass opacity.     

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.     

Pulmonary nontuberculous mycobacterial infection: radiologic manifestations.

The nontuberculous mycobacteria (NTMB) are a group of bacteria that can infect the cervical lymph nodes, skin, soft tissues, and lung. Pulmonary NTMB disease is increasing in prevalence and is most commonly caused by Mycobacterium avium-intracellulare or M kansasii. Occasionally, M xenopi, M fortuitum, or M chelonae also causes pulmonary disease. Diagnosis of pulmonary NTMB infection is often difficult because isolation of the organism from sputum or bronchoalveolar lavage fluid can represent airway colonization. The radiologic manifestations of pulmonary NTMB infection are protean and include consolidation, cavitation, fibrosis, nodules, bronchiectasis, and adenopathy. Pulmonary NTMB infection has five distinct clinicoradiologic manifestations: (a) classic infection, (b) nonclassic infection, (c) nodules in asymptomatic patients, (d) infection in patients with achalasia, and (e) infection in immunocompromised patients. Although classic NTMB infection may be indistinguishable from active tuberculosis, it is usually more indolent. The radiologic features of nonclassic NTMB infection are characteristic: bronchiectasis and centrilobular nodules isolated to or most severe in the lingula and middle lobe. In patients with acquired immunodeficiency syndrome, mediastinal or hilar adenopathy is the most common radiographic finding. Knowledge of the full spectrum of clinical and radiologic features of pulmonary NTMB infection is important to facilitate diagnosis and treatment.     

Disseminated nontuberculous mycobacterial infection mimic metastases on PET/CT scan.

A 68-year-old man had malaise, weight loss, and enlarged right cervical lymph nodes. The first biopsy from a right cervical lymph node showed granulomas with negative acid-fast bacillus (AFB) staining, and he was treated for extrapulmonary tuberculosis with isoniazid, rifampin, ethambutol, and pyrazinamide. Symptoms persisted even after receiving antituberculosis drugs for 2 months. He was transferred to our center for F-18 FDG PET/CT scan under the suspicion of occult malignancy. The PET/CT scan showed increased FDG uptake in the right cervical lymphadenopathy and multiple bony lesions. The second biopsy from the FDG-avid cervical lymph node and bone marrow confirmed nontuberculous mycobacterial (NTM) infection. After another 6 months of adjusted antituberculosis therapy with isoniazid, rifampin, ethambutol, and clarithromycin, a repeat PET/CT scan showed remission of previous lesions.     

Pulmonary thin-section CT findings in acute Moraxella catarrhalis pulmonary infection

Objective

Moraxella catarrhalis is an important pathogen in the exacerbation of chronic obstructive pulmonary disease. The aim of this study was to assess the clinical and pulmonary thin-section CT findings in patients with acute M. catarrhalis pulmonary infection.

Methods

Thin-section CT scans obtained between January 2004 and March 2009 from 292 patients with acute M. catarrhalis pulmonary infection were retrospectively evaluated. Clinical and pulmonary CT findings in the patients were assessed. Patients with concurrent infection including Streptococcus pneumoniae (n = 72), Haemophilus influenzae (n = 61) or multiple pathogens were excluded from this study.

Results

The study group comprised 109 patients (66 male, 43 female; age range 28–102 years; mean age 74.9 years). Among the 109 patients, 34 had community-acquired and 75 had nosocomial infections. Underlying diseases included pulmonary emphysema (n = 74), cardiovascular disease (n = 44) or malignant disease (n = 41). Abnormal findings were seen on CT scans in all patients and included ground-glass opacity (n = 99), bronchial wall thickening (n = 85) and centrilobular nodules (n = 79). These abnormalities were predominantly seen in the peripheral lung parenchyma (n = 99). Pleural effusion was found in eight patients. No patients had mediastinal and/or hilar lymph node enlargement.

Conclusions

M. catarrhalis pulmonary infection was observed in elderly patients, often in combination with pulmonary emphysema. CT manifestations of infection were mainly ground-glass opacity, bronchial wall thickening and centilobular nodules.Moraxella catarrhalis is a Gram-negative, aerobic, oxidase-positive diplococcus that was first described in 1896 [1]. The pathogen, also known as Micrococcus catarrhalis, Neisseria catarrhalis and Brahamella catarrhalis, is a clinically important pathogen and is a common cause of respiratory infections, particularly otitis media in children and lower respiratory tract infection in elderly patients [2-5]. M. catarrhalis is considered to be the third most common and most important cause of bronchopulmonary infections after Streptococcus pneumoniae and Haemophilus influenzae [6,7]. In the Alexander project in Europe and the US between 1992 and 1993, M. catarrhalis was identified in 13.5% of bacterial isolates [8].M. catarrhalis has also gained attention as a nosocomial respiratory pathogen and as a community-acquired pathogen. On the basis of epidemiological evidence, the spread of M. catarrhalis was suggested to occur within the hospital environment [9,10]. McLeod et al [11] reported that 43 of 81 patients (53%) with M. catarrhalis infection were infected in a hospital and that the infection was associated with the proximity of the patient to other patients. Most nosocomial infections with M. catarrhalis involve the respiratory tract and outbreaks have been reported in respiratory units and paediatric intensive care units [10,12].M. catarrhalis infection has received increasing attention because it is an important factor in the acute exacerbation of chronic obstructive pulmonary disease (COPD). Acute exacerbation is a frequent event during the prolonged chronic course of COPD, which entails significant morbidity and mortality. The main aetiology for the majority of episodes is infection.Al-Anazi et al [13] reported a CT image of pneumonia associated with M. catarrhalis in a haematopoietic stem cell transplant patient. However, to the best of our knowledge, no other English-language studies of pulmonary CT findings in patients with acute M. catarrhalis pulmonary infection have been published. Therefore, this study aimed to assess the clinical and pulmonary thin-section CT findings in acute M. catarrhalis pulmonary infection.     

高分辨CT诊断成年囊性纤维化病人非结核性分枝杆菌感染:准确性分析

目的评价高分辨CT诊断囊性纤维化成人中非结核性分枝杆菌(NTM)感染的准确性。方法对27例痰培养证实为非结核性分枝杆菌感染(NTM+)的囊性纤维化病人进行高分辨CT检查。选取27例年龄、性别、呼吸状况匹配,但无非结核性分枝杆菌感染(NTM-)的囊性纤维化病人作为对照组。两位阅片者采用随机盲法按照改良的Bhalla评分标准对所有影像进行评价分析。结果 NTM+组与NTM-组病人在支气管扩张[45%(1.8/4)与35%(1.4/4),P=0.029]、肺泡塌陷/实变[33%(1.3/3)与15%(0.6/3)]、树芽征/小叶中心结节[43%(1.7/3)与25%(1.0/3),P=0.002]等方面以及总的CT评分[56%(18.4/33)和46%(15.2/33),P=0.002]的严重程度都存在明显差异。二元逻辑回归分析显示体质量指数(BMI)、支气管壁增厚、肺泡塌陷/实变和树芽征/小叶中心结节可预测NTM的发生(R2=0.43)。ROC曲线分析显示曲线下面积为0.89,P<0.0001。结论在成年囊性纤维化病人中,高分辨CT上发现7个或7个以上支气管肺段出现树芽征或小叶中心结节时,应高度怀疑NTM感染。     

High-resolution CT of nontuberculous mycobacterium infection in adult CF patients: diagnostic accuracy

European Radiology - To determine the diagnostic accuracy of high-resolution computed tomography (HRCT) for the detection of nontuberculous mycobacterium infection (NTM) in adult cystic fibrosis...     

Persistent pulmonary nodular ground-glass opacity at thin-section CT: histopathologic comparisons

PURPOSE: To retrospectively compare pure pulmonary ground-glass opacity (GGO) nodules observed on thin-section computed tomography (CT) images with histopathologic findings. MATERIALS AND METHODS: The institutional review board approved this study and waived informed consent. Histopathologic specimens were obtained from 53 GGO nodules in 49 patients. CT scans were assessed in terms of nodule size, shape, contour, internal characteristics, and the presence of a pleural tag. The findings obtained were compared with histopathologic results. Differences in thin-section CT findings according to histopathologic diagnoses were analyzed by using the Kruskal-Wallis test or Fisher exact test. RESULTS: Of 53 nodules in 49 patients (20 men, 29 women; mean age, 54 years; range, 29-78 years), 40 (75%) proved to be broncholoalveolar cell carcinoma (BAC) (n=36) or adenocarcinoma with predominant BAC component (n=4), three (6%) atypical adenomatous hyperplasia, and 10 (19%) nonspecific fibrosis or organizing pneumonia. No significant differences in morphologic findings on thin-section CT scans were found among the three diseases (all P>0.05). A polygonal shape (25%, 10 of 40 nodules) and a lobulated or spiculated margin (45%, 18 of 40) in BAC or adenocarcinoma with predominant BAC component were caused by interstitial fibrosis or infiltrative tumor growth. A polygonal shape and a lobulated or spiculated margin were observed in two (20%) and three (30%) of 10 nodules, respectively, in organizing pneumonia/fibrosis were caused by granulation tissue aligned in a linear manner in perilobular regions with or without interlobular septal thickening. CONCLUSION: About 75% of persistent pulmonary GGO nodules are attributed to BAC or adenocarcinoma with predominant BAC component, and at thin-section CT, these nodules do not manifest morphologic features that distinguish them from other GGO nodules with different histopathologic diagnoses.     

肺非结核性分支杆菌病的X线和CT表现

目的 认识肺非结核性分支杆菌病的X线和CT表现。方法 回顾性分析经确诊的22例肺非结核性分支杆菌病的X线胸片表现，其中10例同时有CT扫描。记录异常所见和主要累及的肺叶；比较胸片和CT所见的异同。结果 胸片显示：(1)全部病例都有病变；(2)病变多数为两侧多叶分布(17例)，右侧比左侧多(20：16，)，上叶比下叶多(18：15)；(3)在病变形态上斑片状实变(19例)、空洞(18例)、纤维性变(14例)、结节(12例)是胸片上的主要表现；(4)多数病例(19例)多种病变同时出现。CT则以结节最常见(10例均可见)，其次为实变和空洞，各为8例，此外尚可见5例支气管扩张、3例“树芽征”和2例纵隔淋巴结肿大，这些征象在胸片上均未能检出。结论 气腔实变、空洞、结节、纤维化是胸片的常见表现，在CT上还可见支气管扩张、“树芽征”和纵隔淋巴结肿大。该病变的形态和分布难以和继发型肺结核区别，多种病变同时累及多肺叶是该病的特点。     

Minute pulmonary meningothelial-like nodules: thin-section CT appearance

Minute pulmonary meningothelial-like nodules are often incidentally discovered during pathologic evaluation of pulmonary parenchymal specimens. These lesions were once thought to represent pulmonary chemodectomas, but pathological studies have shown that they are not of neuroendocrine origin. Minute pulmonary meningothelial-like nodules are benign, perhaps reactive in nature, but are occasionally found in association with lung carcinoma. They may appear as randomly distributed well-defined micronodules on thin-section chest CT, and thus may simulate metastatic disease when associated with lung carcinoma.