Adjusted subpixel method enables optimisation of bronchial measurements in high-resolution CT

Objectives

The purpose of this paper is to present a new technique of high-resolution computed tomography (HRCT) bronchial measurement, which was worked out in our centre and is based on a mathematically adjusted subpixel method (ASM).

Methods

This study used a bronchial tree model comprising two polyvinyl chloride/rubber pipes with various densities placed in a larger plastic object. External and internal diameters of both pipes corresponded to the sizes of structures that are usually evaluated in HRCT scans (i.e. the bronchus with accompanying blood vessel). The model was subjected to repeated HRCT measurements of the external and internal diameters of model pipes using a subpixel technique and ASM.

Results

Significant differences were observed between mean values of external and internal diameters of model pipes determined by means of subpixel method or ASM, with the latter being the ones that resembled real diameters of the model pipes more closely. Mean external diameters of the larger and smaller model pipes determined by ASM differed from the real diameters by 0.23% and 0.57%, respectively. The internal diameter of the larger pipe was on average 25.96% larger, whereas the internal diameter of the smaller pipe was 48.05% smaller than the real diameter.

Conclusion

The technique of non-linear prediction of HRCT bronchial measurements described in this paper raises attractive prospects in its clinical application owing to potential improvements in the objectivity and reproducibility of bronchial wall measurements.High-resolution CT (HRCT) has recently gained increasing attention as an evaluation method of bronchial remodelling in asthma patients [1]. The efficiency of HRCT has been proven by numerous studies [2-5]. Optimisation of the radiation beam parameters enables identification of structures down to 100–200 μm in size and allows for evaluation of even the smallest bronchi (1.5–2 mm in diameter) [6]. Because of the aforementioned characteristics, HRCT is useful in the diagnosis and evaluation of many pathologies, including bronchial wall thickening, bronchiectasis, mucus plugging and emphysema or atelectasis [7-11].Owing to its many advantages, HRCT is likely to become the standard tool for disease evaluation in patients with difficult/refractory asthma [12-15]. However, a number of constraints are associated with the application of this otherwise valuable method. The first constraint is the lack of clearly defined clinical criteria for asthma evaluation in HRCT scans [16]. Among the proposed criteria, disease-related changes in bronchial wall thickness and bronchial lumen diameter seem to be the most reasonable. However, repeating and comparing measurements obtained at different time points is often frustrated by the low reproducibility of HRCT-based measurements. This problem results mostly from the wide use of eye-driven, non-standardised techniques of measurements.A number of attempts towards optimising HRCT measurements have been undertaken, mostly based on model systems and mathematical corrections. However, all of the proposed solutions are based on eye-driven measurements [10,17-22]. The purpose of this paper is to present a new technique of HRCT bronchial measurement, which was worked out in our centre and is based on a mathematically adjusted subpixel method (ASM).     

Bronchiolitis Obliterans (BO): HRCT findings in 20 patients

Introduction

Bronchiolitis obliterans (BO), also known as constrictive bronchiolitis is a fibrosing form of obstructive lung disease that follows a severe insult to the lower respiratory tract. It occurs in a heterogenous group of lesions varying in their etiology, clinical settings and pathologic features but are centered in small conducting airways.

Patients and methods

The study included 20 patients 14 females and 6 males, mean age range 7–64 years (average of 39.25 years) with a variety of chest symptoms on whom HRCT was performed.

Results

Mosaic attenuation pattern was seen in all patients. Other HRCT findings included bronchiectasis, bronchial wall thickening and centrilobular nodules.

Conclusion

High-resolution CT is currently superior as an imaging modality in diagnosis of bronchiolitis obliterans, however, diagnosis of BO requires exclusion of other causes of chronic airway obstruction.     

High-resolution computed tomographic findings of Aspergillus infection in lung transplant patients

Objective

The aim of this study was to assess high-resolution computed tomographic (HRCT) findings at presentation in lung transplant patients diagnosed with pulmonary Aspergillus infection.

Materials and methods

We retrospectively reviewed HRCT findings from 23 patients diagnosed with pulmonary aspergillosis. Imaging studies were performed 2–5 days after the onset of symptoms. The patient sample comprised 12 men and 11 women aged 22–59 years (mean age, 43.6 years). All patients had dyspnea, tachypnea, and cough. Diagnoses were established with Platelia Aspergillus enzyme immunoassays for galactomannan antigen detection in bronchoalveolar lavage and recovery of symptoms, and HRCT findings after voriconazole treatment. The HRCT scans were reviewed independently by two observers who reached a consensus decision.

Results

The main HRCT pattern, found in 65% (n = 15) of patients, was centrilobular tree-in-bud nodules associated with bronchial thickening. This pattern was described in association with areas of consolidation and ground-glass opacities in 13% (n = 3) of patients. Consolidation and ground-glass opacities were the main pattern in 22% (n = 5) of patients. The pattern of large nodules with and without the halo sign was observed in 13% (n = 3) of patients, and were associated with consolidation and ground-glass opacities in one case.

Conclusion

The predominant HRCT findings in lung transplant patients with pulmonary aspergillosis were bilateral bronchial wall thickening and centrilobular opacities with the tree-in-bud pattern. Ground-glass opacities and/or bilateral areas of consolidation were also common findings. Pulmonary nodules with the halo sign were found in only 13% of patients.     

Role of the chest radiography,spirometry, and high resolution computed tomography in the early diagnosis of the emphysema

Purpose

This study was performed to evaluate the role of the chest radiography pulmonary function tests, and HRCT in the early diagnosis of the emphysema.

Materials and methods

The study included 50 patients who had emphysema. Average age varies between 40 and 60 years. All patients were subjected to full history, clinical examination, laboratory investigations, cardiac investigations, chest radiography, pulmonary function tests and HRCT.

Results

I found high sensitivity of the HRCT in the early diagnosis of emphysema if compared with sensitivity of the chest radiography and pulmonary function tests.

Conclusions

HRCT has much greater sensitivity than chest radiography in early diagnosing of emphysema. HRCT is also capable of differentiating between the various types of emphysema and assessing its severity. The presence of emphysema can be suspected on chest radiography but this is not a sensitive technique for diagnosis. Also the chest radiography is not a very good indicator for the severity of disease. In addition a precise characterization of the emphysema by HRCT is desirable for adequate therapy and monitoring as well as preoperative assessment of the patient before surgical treatment of emphysema. Compared to spirometry, HRCT shows regional assessment of compartments involved (airways, parenchyma and vasculature). Moreover spirometry has no definite sensitivity.     

Chest HRCT signs predict deaths in long-term follow-up among asbestos exposed workers

Objectives

To study associations between chest HRCT signs and subsequent deaths in long-term follow-up.

Methods

Lung and pleural signs of 633 asbestos exposed workers (age 45–86, mean 65) screened with HRCT were recorded by using the International Classification of Occupational and Environmental Respiratory Diseases (ICOERD) system, which contains detailed instructions for use and reference images. Subsequent mortality was checked from the national register. Cox regression adjusted for covariates (age, sex, BMI, asbestos exposure, pack-years) was used to explore the relations between HRCT signs and all-cause deaths, cardiovascular and benign respiratory deaths, and deaths from neoplasms – all according to the ICD-10 diagnostic system.

Results

The follow-up totalled 5271.9 person-years (mean 8.3 y/person, range .04–10.3). 119 deaths were reported. Irregular/linear opacities, honeycombing, emphysema, large opacities, visceral pleural abnormalities and bronchial wall thickening were all significantly related to all-cause deaths. Most of these signs were associated also with deaths from neoplasms and benign respiratory disease. Deaths from cardiovascular disease were predicted by emphysema and visceral pleural abnormalities.

Conclusions

Several HRCT signs predicted deaths. Careful attention should be paid on subjects with radiological signs predictive of deaths and new secondary preventive strategies developed. This calls for further focused studies among different populations.     

Multidetector CT chest with bronchial and pulmonary angiography determining causes,site and vascular origin of bleeding in patients with hemoptysis

Objective

To assess the role of MDCT chest with bronchial and pulmonary angiography in determining the cause, site of bleeding, and its vascular origin in patients presenting with hemoptysis.

Materials and methods

Fifty patients suffering from hemoptysis were evaluated by MDCT with bronchial and pulmonary angiographic techniques.

Results

MDCT chest with angiography revealed the cause in 84% of cases, the site and vascular origin in 76% of cases presenting with hemoptysis.

Conclusion

MDCT of the chest with bronchial and pulmonary angiography is considered a primary noninvasive imaging modality in the evaluation of patients with hemoptysis. It also serves as a guide for other diagnostic or therapeutic procedures.     

Pulmonary high-resolution computed tomography findings in nephropathia epidemica

Purpose

To evaluate lung high-resolution computed tomography (HRCT) findings in patients with Puumala hantavirus-induced nephropathia epidemica (NE), and to determine if these findings correspond to chest radiograph findings.

Materials and methods

HRCT findings and clinical course were studied in 13 hospital-treated NE patients. Chest radiograph findings were studied in 12 of them.

Results

Twelve patients (92%) showed lung parenchymal abnormalities in HRCT, while only 8 had changes in their chest radiography. Atelectasis, pleural effusion, intralobular and interlobular septal thickening were the most common HRCT findings. Ground-glass opacification (GGO) was seen in 4 and hilar and mediastinal lymphadenopathy in 3 patients. Atelectasis and pleural effusion were also mostly seen in chest radiographs, other findings only in HRCT.

Conclusion

Almost every NE patient showed lung parenchymal abnormalities in HRCT. The most common findings of lung involvement in NE can be defined as accumulation of pleural fluid and atelectasis and intralobular and interlobular septal thickening, most profusely in the lower parts of the lung. As a novel finding, lymphadenopathy was seen in a minority, probably related to capillary leakage and overall fluid overload. Pleural effusion is not the prominent feature in other viral pneumonias, whereas intralobular and interlobular septal thickening are characteristic of other viral pulmonary infections as well. Lung parenchymal findings in HRCT can thus be taken not to be disease-specific in NE and HRCT is useful only for scientific purposes.     

Cost effectiveness of high resolution computed tomography with interferon-gamma release assay for tuberculosis contact investigation

Background

Tuberculosis contact investigation is one of the important public health strategies to control tuberculosis worldwide. Recently, high resolution computed tomography (HRCT) has been reported as a more accurate radiological method with higher sensitivity and specificity than chest X-ray (CXR) to detect active tuberculosis. In this study, we assessed the cost effectiveness of HRCT compared to CXR in combination with QuantiFERON^®-TB Gold In-Tube (QFT) or the tuberculin skin test (TST) for tuberculosis contact investigation.

Methods

We constructed Markov models using a societal perspective on the lifetime horizon. The target population was a hypothetical cohort of immunocompetent 20-year-old contacts with smear-positive tuberculosis patients in developed countries. Six strategies; QFT followed by CXR, QFT followed by HRCT, TST followed by CXR, TST followed by HRCT, CXR alone and HRCT alone were modeled. All costs and clinical benefits were discounted at a fixed annual rate of 3%.

Results

In the base-case analysis, QFT followed by HRCT strategy yielded the greatest benefit at the lowest cost ($US 6308.65; 27.56045 quality-adjusted life-years [QALYs])[year 2012 values]. Cost-effectiveness was sensitive to BCG vaccination rate.

Conclusions

The QFT followed by HRCT strategy yielded the greatest benefits at the lowest cost. HRCT chest imaging, instead of CXR, is recommended as a cost effective addition to the evaluation and management of tuberculosis contacts in public health policy.     

Comparison of initial high resolution computed tomography features in viral pneumonia between metapneumovirus infection and severe acute respiratory syndrome

Objective

To review and compare initial high resolution computed tomography (HRCT) findings in patients with metapneumovirus pneumonia and severe acute respiratory syndrome (SARS-Coronovirus).

Materials and methods

4 cases of metapneumovirus pneumonia (mean age of 52.3 years) in an institutional outbreak (Castle Peak Hospital) in 2008 and 38 cases of SARS-coronovirus (mean age of 39.6 years) admitted to Tuen Mun hospital during an epidemic outbreak in 2003 were included. HRCT findings of the lungs for all patients were retrospectively reviewed by two independent radiologists.

Results

In the metapneumovirus group, common HRCT features were ground glass opacities (100%), consolidation (100%), parenchymal band (100%), bronchiectasis (75%). Crazy paving pattern was absent. They were predominantly subpleural and basal in location and bilateral involvement was observed in 50% of patients. In the SARS group, common HRCT features were ground glass opacities (92.1%), interlobular septal thickening (86.8%), crazy paving pattern (73.7%) and consolidation (68%). Bronchiectasis was not seen. Majority of patient demonstrated segmental or lobar in distribution and bilateral involvement was observed in 44.7% of patients. Pleural effusion and lymphadenopathy were of consistent rare features in both groups.

Conclusion

Ground glass opacities, interlobular septal thickening and consolidations were consistent HRCT manifestations in both metapneumovirus infection and SARS. The presence of bronchiectasis (0% in SARS) may point towards metapneumovirus while crazy paving pattern is more suggestive of SARS.     

Herpes-Simplex-Virus 1 pneumonia in the immunocompromised host: high-resolution CT patterns in correlation to outcome and follow-up

Objective

To identify the high-resolution CT (HRCT) patterns of Herpes-Simplex-Virus 1 (HSV) pneumonia in immunocompromised patients and correlate findings to outcome and radiographic follow-up until death or complete resolution of findings.

Patients and methods

HRCT data-sets and plain radiographic follow-ups were reviewed in 25 immunocompromised patients with confirmation of new onset HSV-1 pneumonia. Pattern and distribution of abnormalities was assessed by two chest radiologists and findings evaluated regarding outcome and dynamics.

Results

The most frequent CT abnormalities included ground-glass attenuation (n = 18; 72%) in a bilateral, symmetric and random distribution, air-space consolidations (n = 13; 52%) in a bilateral, asymmetric and peribronchial allocation and interlobular septal thickening (n = 6; 24%).When classified by leading HRCT pattern, patients subdivided into distinct groups with either dominant ground-glass attenuation or air-space consolidation. Six patients died after a median 8 days of diagnosis; the median interval until complete radiographic remission of pathology was 20 days. Pre-dominance of air-space consolidations was associated with significant delay of improvement (p = 0.023); however, patient outcome was comparable in both subgroups (p = 0.9).

Conclusion

Diagnosis of HSV pneumonia is challenging and requires familiarity with two distinct HRCT patterns: predominance of ground-glass opacities or air-space consolidations. Whilst the two forms are not linked to patient outcome they demonstrate a variable dynamic at follow-up.     

Nonspecific interstitial pneumonia: histologic correlation with high-resolution CT in 29 patients

Purpose

To determine the pathological correlation with various high-resolution CT (HRCT) findings in cases with nonspecific interstitial pneumonia (NSIP), paying special attention to pathological subgroups.

Material and methods

The study involved 29 patients diagnosed with NSIP by surgical lung biopsy. A total of 54 specimens were obtained and grouped according to Katzenstein's classification (groups 1–3) for NSIP. Two observers then evaluated the HRCT findings for every biopsy site and classified the findings according to the main pattern evident into the following four radiologic pattern groups: A, ground-glass attenuation and fine reticulation; B, ground-glass and coarse reticulation; C, consolidation and D, ground-glass attenuation and consolidation.

Results

The pathological pattern was NSIP group 1 in 6 patients, group 2 in 22 and group 3 in 25, while 1 specimen was normal. The main HRCT pattern was pattern A in 15 specimens, B in 8, C in 9 and D in 21. Although there were no significant correlation between HRCT patterns and histological subgroups (Chi-square test, p = 0.07), pattern C was more frequently seen in group 2 (7 of 9) and pattern A was more common in group 3 (11 of 15). HRCT pattern A corresponded pathologically to areas of thickened alveolar septa with temporal uniformity. Pattern B correlated with areas with airspace enlargement/emphysema or dilation of small airways superimposed on thickened alveolar septa. Pattern C was pathologically associated with areas of severe thickened alveolar septa, mucin stasis in the small airways and intraluminal organization.

Conclusion

The pathological backgrounds of the same CT findings in patients with NSIP varied among all pathological subgroups. Areas of ground-glass attenuation and air-space consolidation did not always correspond to reversible pathological findings.     

Bronchiolitis Obliterans after Allogenic Bone Marrow Transplantation: HRCT Findings

Objective

To evaluate the high resolution computed tomography (HRCT) findings of bronchiolitis obliterans (BO) after bone marrow transplantation (BMT).

Materials and Methods

During the past three years, 11 patients were diagnosed as having BO after BMT when they developed irreversible air flow obstruction, with an FEV₁ value of less than 80% of the baseline value, without any clinical evidence of infection. All 11 patients underwent HRCT, of whom eight also underwent follow-up HRCT. The HRCT images were assessed retrospectively for the presence of decreased lung attenuation, segmental or subsegmental bronchial dilatation, diminution of peripheral vascularity, centrilobular nodules, and branching linear structure on the inspiratory images. The lobar distribution of the decreased lung attenuation and bronchial dilatation was also examined. The presence of air trapping was investigated on the expiratory images. The interval changes of the HRCT findings were evaluated in those patients who had follow-up images.

Results

Abnormal HRCT findings were present in all cases; the most common abnormalities were decreased lung attenuation (n=11), subsegmental bronchial dilatation (n=6), diminution of peripheral vascularity (n=6), centrilobular nodules or branching linear structure (n=3), and segmental bronchial dilatation (n=3). Expiratory air trapping was noted in all patients. The decreased lung attenuation and bronchial dilatations were more frequent or extensive in the lower lobes. Interval changes were found in all patients with follow-up HRCT: increased extent of decreased lung attenuation (n=7); newly developed or progressed bronchial dilatation (n=4); and increased lung volume (n=3).

Conclusion

HRCT scans are abnormal in patients with BO, with the most commonly observed finding being areas of decreased lung attenuation. While the HRCT findings are not specific, it is believed that their common features can assist in the diagnosis of BO in BMT recipients.     

Incomplete and accessory fissures of the lung evaluated by high-resolution computed tomography

Purpose

The aim of our study was to assess incomplete and accessory interlobar fissures using volumetric thin-section high-resolution computed tomography (HRCT).

Materials and methods

Retrospective assessment of HRCT examinations of 250 patients was performed. We assessed the localization, extension, and type of the incompleteness of fissures as well as the presence and localization of accessory fissures. We searched for possible correlation among the localization of interlobar fissures, the presence of incompleteness, and accessory fissures.

Results

On the left side, an incomplete oblique fissure was found in 24%. The discontinuity was present in the parahilar region and the area of the incompleteness was most frequently between 21% and 40%. The right oblique fissure was incomplete in 35%, mostly parahilarly, with the most frequent discontinuity below 20%. An incomplete horizontal fissure was found in 74%. Accessory fissures were identified in 16% of patients, with the same frequency on both sides. The most frequent finding was accessory horizontal fissure with 8.0% on the left side, superior accessory fissure (7.2%) and inferior accessory fissure (5.2%) on the right side. No correlation was found among the localization of interlobar fissures, the presence of incompleteness, and accessory fissures.

Conclusion

Incomplete and accessory fissures are frequent anatomic variations of interlobar fissures.     

Comparative study of clinical, pathological and HRCT findings of primary alveolar proteinosis and silicoproteinosis

Objective

To compare the clinical, high-resolution computed tomography (HRCT) and pathological findings of primary alveolar proteinosis (PAP) and silicoproteinosis.

Material and methods

The study included 15 patients with PAP (6 women, 9 men, mean age 31 years) and 13 with silicoproteinosis (13 men, mean age 29.5 years). PAP was diagnosed by lung biopsy in 13 and bronchoalveolar lavage in two patients and silicoproteinosis by bronchoalveolar lavage in 10 and autopsy in three cases. HRCT images were reviewed by two chest radiologists with consensus for the presence, extent and distribution of ground-glass opacities, septal thickening, consolidation and nodules. Radiological–pathological correlation was performed by one radiologist and one chest pathologist.

Results

Seven (46%) patients with PAP were asymptomatic; the remainder presented slowly progressive dyspnea and dry cough. All silicoproteinosis patients had dry cough and rapidly progressive dyspnea. The most common HRCT finding on PAP was the crazy-paving pattern (93%). All cases had areas of geographic sparing in the affected lung. The most common finding in silicoproteinosis (92%) was dependent consolidation with calcification in 83%. Centrilobular nodules were common (85%). On pathology, both diseases demonstrated intra-alveolar accumulation of PAS material, thickening of interlobular septae and alveolar walls and no evidence of fibrosis. A few silica particles were seen in silicoproteinosis.

Conclusion

Despite the pathological similarities, PAP and silicoproteinosis have distinct clinical and imaging features and prognosis. Bilateral crazy-paving pattern with areas of geographic sparing is characteristic for PAP. Silicoproteinosis presents with bilateral dependent consolidation often with areas of calcification. The crazy-paving pattern is not seen in silicoproteinosis.     

Radiological abnormalities associated with Aspergillus colonization in a cystic fibrosis population

Objective

To determine if sputum colonization with Aspergillus species in patients with cystic fibrosis (PWCF) correlates with radiological abnormalities and/or a reduction in pulmonary function (FEV1).

Methods

We prospectively evaluated 32 PWCF utilizing high resolution computed tomography (HRCT) of the thorax and pulmonary function testing (PFT). The cohort was assessed as two groups: Aspergillus positive (n = 16) and Aspergillus negative (n = 16) based on sputum culture for Aspergillus species. A modified Bhalla scoring system was applied to each HRCT scan by two blinded radiologists.

Results

Aspergillus positive patients had more severe and significant bronchiectasis compared to those Aspergillus negative (p < 0.05). This was most marked in the right upper and lower lobes (RUL, RLL). Total Bhalla score was clinically significant in both groups and approached statistical significance between groups (p = 0.063). No difference in pulmonary function between the groups was detected.

Conclusion

PWCF colonized by Aspergillus species have greater radiological abnormalities undetectable by PFTs. Early radiological evaluation of Aspergillus colonized PWCF is therefore warranted.     

Clinical Impact of Multidetector Row Computed Tomography Before Bronchial Artery Embolization in Patients With Hemoptysis: A Prospective Study

Purpose

To evaluate prospectively the role and impact of multidetector row computed tomography (MDCT) before bronchial artery embolization (BAE) in patients with hemoptysis.

Methods

MDCT of the thorax was performed in 27 patients (21 men, 6 women; age range, 22-70 years; mean, 39 years) with hemoptysis who were referred for BAE. Transverse, multiplanar reconstruction, and 3-dimensional reconstruction (maximum intensity projection and volume rendered) images were analysed to identify the abnormal hypertrophied bronchial and nonbronchial systemic arteries causing hemoptysis, their origin and course were noted. Digital subtraction angiography was performed with the knowledge of findings of MDCT. Selective arteriogram of abnormal bronchial as well as nonbronchial arteries was performed. Embolization was attempted in 25 of these patients (92.6%) by using polyvinyl alcohol particles (350-500 μm), Gelfoam or Embospheres (400-700 μm). Follow-up was done for a mean period of 20.5 months.

Results

Based on MDCT, 2 of 27 patients were found unsuitable for BAE. On computed tomography, 38 arteries (27 bronchial and 11 nonbronchial systemic arteries) were identified as abnormal hypertrophied vessels. On angiography, 34 of these arteries (25 bronchial and 9 nonbronchial systemic arteries) were found to be responsible for hemoptysis. Three of these arteries could not be evaluated during angiography, and 1 artery that was identified as abnormal on computed tomography was found normal on angiography. All 25 bronchial and 9 nonbronchial systemic arteries that cause hemoptysis were detected at MDCT. Embolization was successful in 23 of 25 patients.

Conclusion

MDCT enables detection and depiction of all bronchial and nonbronchial systemic arteries causing hemoptysis.     

The value of power and pulsed Doppler in the diagnosis of CTS: Is a solution in sight

Objective

To evaluate the value of power and pulsed Doppler in diagnosis of CTS and compare it with median nerve cross-sectional area (CSA) measured by gray-scale US and nerve conduction studies.

Patients and methods

Forty patients with definite clinical evidence of CTS and 20 healthy cases were enrolled in the study. All patients and controls underwent nerve conduction studies, gray-scale US (for measurement of CSA) and color Doppler (for assessment of vasomotor activity).

Results

Twenty eight patients (70%) had confirmed diagnosis by NCS while 12 patients (30%) were not detected by the NCS. The CSA ranged from 0.06 to 0.78 cm² with a mean of 0.19 + 0.12. Comparison between patients and controls as regards CSA showed highly statistically significant difference (P < 0.001). There was a significant difference between patients and controls as regards PS, ED & PI. Also there was a significant correlation between median nerve hypervascularization and the parameters of spectral Doppler and the severity of CTS by NCS and also with CSA.

Conclusion

Color Doppler imaging of the median nerve is a readily accessible and practical method for determining the degree of vasomotor impairment in CTS patients that may be valuable in evaluation and follow up of CTS patients in clinical practice.     

Predictors of Pulmonary Hypertension on High-resolution Computed Tomography of the Chest in Systemic Sclerosis: A Retrospective Analysis

Purpose

To evaluate the imaging features on high-resolution computed tomography (HRCT) of the chest and the clinical parameters that are associated with pulmonary hypertension in systemic sclerosis. We specifically investigated whether main pulmonary artery (MPA) diameter and burden of lung fibrosis are predictors of pulmonary hypertension in these patients.

Methods

We retrospectively retrieved the database information of patients with systemic sclerosis seen at our hospital between January 2007 and December 2008. A total of 75 patients had HRCT of the chest, pulmonary function testing (PFT), and echocardiography within 6 months of each other. The echocardiography images were reviewed by a level-3 echocardiographer, and 29 cases were excluded because of suboptimal evaluation of pulmonary artery (PA) pressure. Peak PA pressures and PFT of the remaining 46 cases (43 women and 3 men) were charted. The PFT included total lung capacity (TLC), diffusion capacity of lung for carbon monooxide (DLCO) and the ratio of forced expiratory volume in one second and forced vital capacity (FEV1/FVC). The HRCT of the chest of each patient was read by a chest radiologist. The extent of ground glass, reticulation, and honeycombing was objectively scored. The maximum diameter of the main pulmonary artery (MPAD) and ascending aorta were measured. The ratio of main pulmonary artery diameter and ascending aortic diameter (MPAD/AD) and ratio of main pulmonary artery diameter and body surface area (MPAD/BSA) were also calculated.

Results

Statistical analysis done by using a multivariate model showed that the calculated fibrotic score strongly correlated with peak PA pressures (P < .001). MPAD (P = .0175), and the ratio MPAD/AD (P = .0102) also showed a statistically significant correlation with peak PA pressures. By using stepwise regression analysis, the fibrotic score was found to be the most reliable independent predictor of pulmonary hypertension.

Conclusion

HRCT-determined severity and extent of pulmonary fibrosis may be helpful in screening for pulmonary hypertension in patients with systemic sclerosis.     

Usual interstitial pneumonia and nonspecific interstitial pneumonia: correlation between CT findings at the site of biopsy with pathological diagnoses

Objectives

The aim of this study was to correlate high-resolution CT (HRCT) findings at the site of biopsy with the whole lung CT and pathologic diagnoses in usual interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP).

Methods

The study included 35 patients (25 UIP and 10 NSIP) diagnosed both pathologically and clinically. 81 surgical biopsy specimens (54 UIP, and 27 NSIP) and extracted areas corresponding to biopsy sites on HRCT were analyzed. CT interpretations were compared with pathological diagnoses in both extracted images and the whole lung. Concordant and discordant cases in multiple extracted images were divided and analyzed. Then the whole cases were categorized by including or not at least one UIP diagnosis of extracted images and evaluated.

Results

The diagnoses in extracted sites significantly correlated with pathological diagnoses (p = 0.047). There were significant differences in the concordances of extracted images compared with the diagnosis of whole lung and pathology (p = 0.008, 0.003, respectively). All 7 cases that were not concordant were diagnosed as radiological UIP with whole lung CT. The cases with at least one UIP diagnosis of extracted CT images were diagnosed as UIP in pathology more frequently (18 in 25) (p = 0.007).

Conclusions

Radiological UIP in whole CT had more frequently discordant diagnoses from multiple extracted images than NSIP. And there were more cases in pathological UIP that included at least one UIP diagnosis of extracted images compared with pathological NSIP.     

High-resolution CT for identify patients with smear-positive, active pulmonary tuberculosis

Purpose

This study evaluates the use of high-resolution computed tomography (HRCT) to differentiate smear-positive, active pulmonary tuberculosis (PTB) from other pulmonary infections in the emergency room (ER) setting.

Methods

One hundred and eighty-three patients diagnosed with pulmonary infections in an ER were divided into an acid fast bacillus (AFB) smear-positive, active PTB group (G1 = 84) and a non-AFB smear-positive, pulmonary infection group (G2 = 99). HRCT images from a 64-Multidetector CT were analyzed, retrospectively, for the morphology, number, and segmental distribution of pulmonary lesions.

Results

Utilizing multivariate analysis, five variables were found to be independent risk factors predictive of G1: (1) consolidation involving the apex segment of right upper lobe, posterior segment of the right upper lobe, or apico-posterior segment of the left upper lobe; (2) consolidation involving the superior segment of the right or left lower lobe; (3) presence of a cavitary lesion; (4) presence of clusters of nodules; (5) absence of centrilobular nodules. A G1 prediction score was generated based on these 5 criteria to help differentiate G1 from G2. The area under the receiver operating characteristic (ROC) curve was 0.96 ± 0.012 in our prediction model. With an ideal cut-off point score of 3, the specificity, sensitivity, positive predictive value (PPV), and negative predictive value (NPV) are 90.9%, 96.4%, 90.0% and 96.8%, respectively.

Conclusion

The use of this AFB smear-positive, active PTB prediction model based on 5 key HRCT findings may help ER physicians determine whether or not isolation is required while awaiting serial sputum smear results in high risk patients.