High resolution CT and bronchography in the assessment of bronchiectasis

What did we learn from two decades of chest computed tomography in cystic fibrosis?

Despite our current treatment, many cystic fibrosis (CF) patients still show progressive bronchiectasis and small airways disease. Adequate detection and monitoring of progression of these structural abnormalities is needed to personalize treatment to the severity of CF lung disease of the patient. Chest computed tomography (CT) is the gold standard to diagnose and monitor bronchiectasis. Many studies have been done to validate the role of chest CT in CF and to improve the protocols. From these studies it became clear that for correct interpretation of the severity of bronchiectasis and small airways disease standardization of lung volume for the inspiratory and expiratory CT scan acquisition is needed. The risk related to the radiation exposure of a chest CT scan every second year is considered low. Automated and quantitative image analysis systems are developed to improve the reliability and sensitivity of assessments of structural lung changes in CF, particularly in early life. In this paper an overview is given of the lessons learned from two decades of monitoring CF lung disease using chest CT.

High-resolution computed tomography bronchial lumen to pulmonary artery diameter ratio in anesthetized ventilated cats with normal lungs

High-resolution computed tomography (CT) is the preferred noninvasive tool for diagnosing bronchiectasis in people. A criterion for evaluating dilation of the bronchus is the bronchial lumen to pulmonary artery diameter (bronchoarterial ratio [BA ratio]). A ratio of > 1.0 in humans or > 2.0 in dogs has been suggested as a threshold for identifying bronchiectasis. The purpose of this study was to establish the BA ratio in normal cats. Fourteen specific pathogen-free cats were selected for analysis of thoracic CT images. The BA ratios of the lobar bronchi of the left cranial (cranial and caudal parts), right cranial, right middle, left caudal, and right caudal lung lobes were measured. The mean of the mean BA ratio of all lung lobes was 0.71 +/- 0.05. Individual BA ratios ranged from 0.5 to 1.11. Comparing individual lobes for each cat, there was no significant difference (P = 0.145) in mean BA ratio between lung lobes. A mean BA ratio for these normal cats was 0.71 +/- 0.1, which suggests an upper cut-off normal value > 0.91 (mean +/- 2 standard deviations) between normal and abnormal cats.

Chest radiographic and computed tomographic manifestations in allergic bronchopulmonary aspergillosis

AIM: To investigate the chest radiographic and high resolution computed tomography (HRCT) chest manifestations in glucocorticoid-naïve allergic bronchopulmonary aspergillosis (ABPA) patients.

METHODS: This is a prospective observational study and includes 60 consecutive glucocorticoid-naïve patients with ABPA who underwent chest radiography and HRCT of the chest (1.25 mm every 10 mm) in the routine diagnostic workup for ABPA.

RESULTS: Chest radiographs were normal in 50% of cases. Of the remainder, most patients demonstrated permanent findings in the form of parallel line and ring shadows suggesting bronchiectasis. Consolidation was detected in 17 cases but in the majority, the corresponding HRCT chest scan showed mucus-filled bronchiectatic cavities. Chest HRCT was normal in 22 patients, while central bronchiectasis (CB) was demonstrated in the remaining 38 patients. Bronchiectasis extended to the periphery in 33%-43% depending on the criteria used for defining CB. The other findings observed on HRCT were mucoid impaction, centrilobular nodules and high-attenuation mucus in decreasing order of frequency.

CONCLUSION: Patients with ABPA can present with normal HRCT chest scans. Central bronchiectasis cannot be considered a characteristic feature of ABPA as peripheral bronchiectasis is commonly observed. Consolidation is an uncommon finding in ABPA.

Diagnosing and preventing chronic suppurative lung disease (CSLD) and bronchiectasis

Current diagnostic labelling of childhood bronchiectasis by radiology has substantial limitations. These include the requirement for two high resolution computerised tomography [HRCT] scans (with associated adversity of radiation) if criteria is adhered to, adoption of radiological criteria for children from adult data, relatively high occurrence of false negative, and to a smaller extent false positive, in conventional HRCT scans when compared to multi-detector CT scans, determination of irreversible airway dilatation, and absence of normative data on broncho-arterial ratio in children. A paradigm presenting a spectrum related to airway bacteria, with associated degradation and inflammation products causing airway damage if untreated, entails protracted bacterial bronchitis (at the mild end) to irreversible airway dilatation with cystic formation as determined by HRCT (at the severe end of the spectrum). Increasing evidence suggests that progression of airway damage can be limited by intensive treatment, even in those predestined to have bronchiectasis (eg immune deficiency). Treatment is aimed at achieving a cure in those at the milder end of the spectrum to limiting further deterioration in those with severe 'irreversible' radiological bronchiectasis.

Automated CT scoring of airway diseases: preliminary results

RATIONALE AND OBJECTIVES

The aim of this study was to retrospectively evaluate an automated global scoring system for evaluating the extent and severity of disease in a known cohort of patients with documented bronchiectasis. On the basis of a combination of validated three-dimensional automated algorithms for bronchial tree extraction and quantitative airway measurements, global scoring combines the evaluation of bronchial lumen-to-artery ratios and bronchial wall-to-artery ratios, as well as the detection of mucoid-impacted airways. The result is an automatically generated global computed tomographic (CT) score designed to simplify and standardize the interpretation of scans in patients with chronic airway infections.

MATERIALS AND METHODS

Twenty high-resolution CT data sets were used to evaluate an automated CT scoring method that combines algorithms for airway quantitative analysis that have been individually tested and validated. Patients with clinically documented atypical mycobacterial infections with visually assessed CT evidence of bronchiectasis varying from mild to severe were retrospectively selected. These data sets were evaluated by two independent experienced radiologists and by computer scoring, with the results compared statistically, including Spearman's rank correlation.

RESULTS

Computer evaluation required 3 to 5 minutes per data set, compared to 12 to 15 minutes for manual scoring. Initial Spearman's rank tests showed positive correlations between automated and readers' global scores (r = 0.609, P = .01), extent of bronchiectasis (r = 0.69, P = .0004), and severity of bronchiectasis (r = 0.61, P = .01), while mucus plug detection showed a lesser extent of positive correlation between the scoring methods (r = 0.42, P = .07) and wall thickness a negative weak correlation (r = -0.10, P = .40). Further retrospective review of 24 lobes in which wall thickness scores showed the highest discrepancy between manual and automated methods was then performed, using electronic calipers and perpendicular cross-sections to reassess airway measurements. This resulted in an improved Spearman's rank correlation to r = 0.62 (P = .009), for a global score of r = 0.67 (P = .001).

CONCLUSION

Automated computerized scoring shows considerable promise for providing a standardized, quantitative method, demonstrating overall good correlation with the results of experienced readers' evaluation of the extent and severity of bronchiectasis. It is speculated that this technique may also be applicable to a wide range of other conditions associated with chronic bronchial inflammation, as well as of potential value for monitoring response to therapy in these same populations.

Surgical management of bronchiectasis in childhood

OBJECTIVE

Though there is a gradual decrease in the prevalence of bronchiectasis, it is still a cause of mortality and morbidity among children in developing countries such as Turkey. We reviewed the morbidity and mortality rates and the outcome of surgical treatment for childhood bronchiectasis.

PATIENTS AND METHODS

Age, sex, etiological factors, symptoms, radiological examinations, surgical procedures, postoperative morbidity and mortality in patients aged 16 years and younger, operated for bronchiectasis between January 1991 and April 2006 in the Thoracic Surgery Clinic of Atatürk Training and Research Hospital for Chest Disease and Chest Surgery were reviewed retrospectively.

RESULTS

Between January 1991 and April 2006, 176 cases aged 16 and younger were operated for bronchiectasis. There were 95 females (54%) and 81 males (46%), with a mean age of 12.3 years (range: 3.4-16 years). The most common cause of bronchiectasis was lung infection (n: 87, 49.4%). Main symptoms were coughing (n: 167, 94.9%), sputum (n: 139, 79%), hemoptysis (n: 78, 44.3%), and fever (n: 77, 43.7%). Mean duration of the symptoms in patients who were operated was 3.8 years (range: 0-7.6 years). Cases underwent a total of 201 operations: 19 cases had bilateral surgical resection and 6 cases had completion pneumonectomy. Majority of cases had complete resection (n: 165, 93.75%) while only 11 cases (6.25%) had incomplete resection. Mean duration of hospitalization was 8.9 days (range: 5-39 days). The outcome, based on the responses of patients postoperatively, was 'perfect' in 129 cases (73.3%), 'improved' in 41 cases (23.3%), and 'no changes' in 6 cases (3.4%). The mean follow-up after surgery was 4.3 years (range: 14 months to 7.2 years), mortality was 0% and morbidity was 13% (n: 23).

CONCLUSION

With acceptable mortality and morbidity rates and high chance of cure after complete resection, surgical treatment is a successful and reliable method of treatment in childhood bronchiectasis that yields marked improvement in the quality of life.

Chest computed tomography scans should be considered as a routine investigation in cystic fibrosis

Cystic fibrosis (CF) patients demonstrate lung inflammation and infection beginning early in life. Both inflammation and infection lead to irreversible structural lung damage, primarily as bronchiectasis and fibrosis. The course of CF varies widely between patients due to genotypic and environmental differences. The primary aim of CF therapy is to prevent or delay structural damage and conserve lung function. Adequate monitoring of CF lung disease is paramount to tailoring treatment to a patient's need. Pulmonary function tests (PFTs) are important in monitoring lung function. PFTs, however, are only an indirect measure of lung structure and are insensitive to localised or early damage. By contrast, computed tomography (CT) is currently the most sensitive tool to monitor lung structure. As up to 50% of patients will have discordant staging of lung disease when PFTs are compared to CT findings, both methods are needed to adequately assess a patient's pulmonary condition and tailor the treatment strategy to the patient's needs.

Conventional High-Resolution CT Versus Helical High-Resolution MDCT in the Detection of Bronchiectasis

OBJECTIVE

The purpose of this study was to compare conventional high-resolution CT (HRCT) with helical 16-MDCT in the detection of bronchiectasis.

MATERIALS AND METHODS

We retrospectively evaluated 80 patients including 61 with bronchiectasis (mean age, 64 years; range, 22-87 years) and a control group of 19 patients with normal MDCT of the chest. Two sets of images were blindly, randomly analyzed by two observers: contiguous 1-mm slices (MDCT set) and 1-mm slices every 10 mm (HRCT set) derived from the MDCT set. Images were scored independently for presence, extent, and severity of bronchiectasis, followed by a consensus interpretation. Kappa analysis assessed inter- and intraobserver agreement. MDCT was the radiologic gold standard.

RESULTS

Of the 61 patients with bronchiectasis diagnosed with MDCT, 56 (92%) were positive for bronchiectasis on conventional HRCT. Seven patients had positive MDCT scans only, and two patients had positive HRCT scans only. Of 479 lobes, 59 were positive for bronchiectasis on MDCT and negative on HRCT, and 19 lobes were positive for bronchiectasis on HRCT and negative on MDCT (p < 0.0001). MDCT showed 25 more lobes with cylindric, 11 more lobes with varicose, and four more lobes with cystic bronchiectasis than did HRCT. Sensitivity, specificity, and positive and negative predictive values of HRCT in detecting bronchiectasis were 71%, 93%, 88%, and 81%, respectively. Interobserver agreement for presence, extent, and severity of bronchiectasis ranged from moderate to good for MDCT (kappa values, 0.64, 0.5, and 0.48, respectively) and poor to good for HRCT (kappa values, 0.65, 0.46, and 0.25, respectively).

CONCLUSION

Contiguous helical 16-MDCT with 1-mm collimation is superior to HRCT at 10-mm intervals in showing the presence and extent of bronchiectasis.

Bronchiectasis, Exacerbation Indices, and Inflammation in Chronic Obstructive Pulmonary Disease

Relationships between high-resolution computed tomography (HRCT) findings in chronic obstructive pulmonary disease (COPD) and bacterial colonization, airway inflammation, or exacerbation indices are unknown. Fifty-four patients with COPD (mean [SD]: age, 69 [7] years; FEV(1), 0.96 [0.33] L; FEV(1) [percent predicted], 38.1 [13.9]%; FEV(1)/forced vital capacity [percent predicted], 40.9 [11.8]%; arterial partial pressure of oxygen, 8.77 [1.11] kPa; history of smoking, 50.5 [33.5] smoking pack-years) underwent HRCT scans of the chest to quantify the presence and extent of bronchiectasis or emphysema. Exacerbation indices were determined from diary cards over 2 years. Quantitative sputum bacteriology and cytokine measurements were performed. Twenty-seven of 54 patients (50%) had bronchiectasis on HRCT, most frequently in the lower lobes (18 of 54, 33.3%). Patients with bronchiectasis had higher levels of airway inflammatory cytokines (p = 0.001). Lower lobe bronchiectasis was associated with lower airway bacterial colonization (p = 0.004), higher sputum interleukin-8 levels (p = 0.001), and longer symptom recovery time at exacerbation (p = 0.001). No relationship was seen between exacerbation frequency and HRCT changes. Evidence of moderate lower lobe bronchiectasis on HRCT is common in COPD and is associated with more severe COPD exacerbations, lower airway bacterial colonization, and increased sputum inflammatory markers.

Reversible bronchial dilatation in children: comparison of serial high-resolution computer tomography scans of the lungs

INTRODUCTION

Bronchiectasis is generally considered irreversible in the adult population, largely based on studies employing bronchography in cases with a significant clinical history. It is assumed, that the same is true for children. Few studies have examined the natural history of bronchiectasis in children and diagnostic criteria on high-resolution computer tomography of the lungs are derived from studies on adults. Frequently, bronchiectasis is reported in children in cases where localised bronchial dilatation is present, incorrectly labelling these children with an irreversible life-long condition.

OBJECTIVE

to evaluate changes in appearance of bronchial dilatation, unrelated to cystic fibrosis in children, as assessed by sequential high-resolution computer tomography (HRCT) of the lungs.

METHODS

The scans of 22 children with a radiological diagnosis of bronchiectasis, seen at Alder Hey Children's Hospital between 1994 and 2000, who had at least two CT scans of the lungs were reviewed by a single radiologist, who was blinded to the original report.

RESULTS

Following a median scan interval of 21 months (range 2-43), bronchial dilatation resolved completely in six children and there was improvement in appearances in a further eight, with medical treatment alone.

DISCUSSION

A radiological diagnosis of bronchiectasis should be considered with caution in children as diagnostic criteria derived from studies in adults have not been validated in children and the condition is generally considered irreversible.

CT of airways disease and bronchiectasis

High-resolution CT is accepted as an accurate noninvasive means of diagnosing bronchiectasis. A wide spectrum of abnormalities may be identified at HRCT in patients with airway disease, including various distinctive patterns of bronchiectasis in specific clinical settings, such as ABPA, MAC infection, AIDS, and CF. Characteristic CT findings occasionally suggest a specific diagnosis that may not have been under clinical consideration. HRCT also provides significant clinical use in assessing the degree and extent of airway disease, and allows noninvasive monitoring of disease progression, regression, or response to therapy.

Haemoptysis: aetiology, evaluation and outcome--a prospective study in a third-world country

Haemoptysis is an alarming symptom, and the management depends upon the aetiology. Emergency management depends upon localization of the site of bleeding by roentgenogram, computerized chest tompgraphy and bronchoscopy. We prospectively evaluated 52 patients with haemoptysis admitted to the Chest Hospital, Kuwait for 1 year (January 1998 to December 1998) and followed them up for 1 year (January 1999 to December 1999). There were 42 males (80.8%) and 10 (19.2%) females, with a mean age of 42.2 (16-86) years. Of these, 26.9% were Kuwaiti nationals, 36.5% were Arab non-Kuwaiti nationals, 34.6% were Asians and 1.9% were other nationals. The aetiologies of haemoptysis were bronchiectasis (21.2%), old pulmonary tuberculosis with bronchiectasis (17.3%), active pulmonary tuberculosis (15.4%), bronchitis (5.8%), aspergilloma, rheumatic heart disease and carcinoid (1.9%). Aetiology could not be identified in 25% of patients. The site of bleeding in haemoptysis could not be localized by the consultants in 18 (32%) by roentgenogram. 16 patients (37%) by CT scan and 23 patients (50%) by Fibreoptic bronchoscopy. Sequential estimation of hemoglobin showed a mean of 13.56 (SD 1.9) and 13.31 (SD 1.8) after 24 h. The difference in mean was statistically significant (p<0.036). Conservative management was given in 80.8%, and embolotherapy or surgical intervention in 19.2% of patients. Only 12% of patients had recurrent haemoptysis at 1-year follow up. In conclusion, bronchiectasis and pulmonary tuberculosis were the major causes of haemoptysis in this study. Roentgenogram, CT scan and fibreoptic bronchoscopy are useful for localizing the site of bleeding. Sequential estimation of haemoglobin may be helpful in assessing the severity of haemoptysis, but larger studies are required to address this observation. The outcome of haemoptysis is generally good, with a low mortality and recurrence rate.

Bronchiectasis

Imaging has a key role in the identification of bronchiectasis. Over the years, imaging tests have become increasingly accurate in depicting the features of early bronchiectasis. This article covers the clinical, pathologic, and functional features of bronchiectasis; high-resolution CT scan technique; the signs of bronchiectasis on chest radiography and high-resolution CT scan; and the causes of misdiagnosis of bronchiectasis.

Expiratory high-resolution CT scan

Although high-resolution CT scan has proved most useful in the diagnosis of infiltrative lung disease, its use in the diagnosis of airway and obstructive lung diseases has recently been emphasized. In particular, the use of dynamic expiratory or postexpiratory CT scans, usually in combination with an inspiratory high-resolution CT scan study, has proved useful in the diagnosis and assessment of obstructive lung diseases. This article reviews the use of expiratory CT scan in the diagnosis of lung disease, including the various CT scan techniques that can be used, normal and abnormal expiratory CT scan findings, and the use of expiratory CT scan in a variety of obstructive diseases.

Bronchiectasis: CT/clinical correlations

The association between bronchiectasis and human immunodeficiency virus infection, the resurgence of tuberculosis, especially in urban and immunocompromised patients, and the recognition of bronchiectasis as a manifestation of rejection in the transplant population are emerging clinical settings in which establishing the diagnosis of bronchiectasis is becoming increasingly important. High-resolution CT, by virtue of its well-established accuracy, is currently accepted as the optimal noninvasive means of diagnosing bronchiectasis. However, reliable diagnosis requires meticulous attention to technique and a thorough knowledge of potential pitfalls. These include, among others, respiratory and cardiac motion artifacts as well as effects of collimation and electronic windowing. It also is important to recognize diseases that may mimic the appearance of bronchiectasis as well as unusual manifestations of bronchiectasis that may obscure the diagnosis.

Pediatric bronchography performed through the flexible bronchoscope

Ten children, ranging in age from 2 months to 16 years, were evaluated by bronchograms performed during bronchoscopy. Nine of the ten children had significant pathology demonstrated by the bronchogram that elucidated findings unclear from other imaging procedures at the time of bronchoscopy. Despite the generally negative opinions about the utility of bronchograms in children, information obtained by bronchography can be quite useful. Bronchography during bronchoscopy proved to be quick, simple, and safe.