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The diagnosis, prognostication, and differentiation of phenotypes of COPD can be facilitated by CT scan imaging of the chest. CT scan imaging of the chest is a prerequisite for lung volume reduction surgery and lung transplantation. Quantitative analysis can be used to evaluate extent of disease progression. Evolving imaging techniques include micro-CT scan, ultra-high-resolution and photon-counting CT scan imaging, and MRI. Potential advantages of these newer techniques include improved resolution, prediction of reversibility, and obviation of radiation exposure. This article discusses important emerging techniques in imaging patients with COPD. The clinical usefulness of these emerging techniques as they stand today are tabulated for the benefit of the practicing pulmonologist., (Copyright © 2023 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

Morphological evaluation of the lung is important in the clinical evaluation of pulmonary diseases. However, the disease process, especially in its early phases, may primarily result in changes in pulmonary function without changing the pulmonary structure. In such cases, the traditional imaging approaches to pulmonary morphology may not provide sufficient insight into the underlying pathophysiology. Pulmonary imaging community has therefore tried to assess pulmonary diseases and functions utilizing not only nuclear medicine, but also CT and MR imaging with various technical approaches. In this review, we overview state-of-the art MR methods and the future direction of: (1) ventilation imaging, (2) perfusion imaging and (3) biomechanical evaluation for pulmonary functional imaging.

Background Deep learning may help to improve computer-aided detection of volume (CADv) measurement of pulmonary nodules at chest CT. Purpose To determine the efficacy of a deep learning method for improving CADv for measuring the solid and ground-glass opacity (GGO) volumes of a nodule, doubling time (DT), and the change in volume at chest CT. Materials and Methods From January 2014 to December 2016, patients with pulmonary nodules at CT were retrospectively reviewed. CADv without and with a convolutional neural network (CNN) automatically determined total nodule volume change per day and DT. Area under the curves (AUCs) on a per-nodule basis and diagnostic accuracy on a per-patient basis were compared among all indexes from CADv with and without CNN for differentiating benign from malignant nodules. Results The CNN training set was 294 nodules in 217 patients, the validation set was 41 nodules in 32 validation patients, and the test set was 290 nodules in 188 patients. A total of 170 patients had 290 nodules (mean size ± standard deviation, 11 mm ± 5; range, 4-29 mm) diagnosed as 132 malignant nodules and 158 benign nodules. There were 132 solid nodules (46%), 106 part-solid nodules (36%), and 52 ground-glass nodules (18%). The test set results showed that the diagnostic performance of the CNN with CADv for total nodule volume change per day was larger than DT of CADv with CNN (AUC, 0.94 [95% confidence interval {CI}: 0.90, 0.96] vs 0.67 [95% CI: 0.60, 0.74]; P < .001) and CADv without CNN (total nodule volume change per day: AUC, 0.69 [95% CI: 0.62, 0.75]; P < .001; DT: AUC, 0.58 [95% CI: 0.51, 0.65]; P < .001). The accuracy of total nodule volume change per day of CADv with CNN was significantly higher than that of CADv without CNN ( P < .001) and DT of both methods ( P < .001). Conclusion Convolutional neural network is useful for improving accuracy of computer-aided detection of volume measurement and nodule differentiation capability at CT for patients with pulmonary nodules. © RSNA, 2020 Online supplemental material is available for this article.

Background:  Magnetic resonance imaging (MRI) of the pulmonary parenchyma is generally hampered by multiple challenges related to patient respiratory- and circulation-related motion, low proton density and extremely fast signal decay due to the structure of the lungs evolved for gas exchange., Methods:  Systematic literature database research as well as annual participation in conferences dedicated to pulmonary MRI for more than the past 20 years by at least one member of the author team., Results and Conclusion:  The problem of motion has been addressed in the past by developments such as triggering, gating and parallel imaging. The second problem has, in part, turned out to be an advantage in those diseases that lead to an increase in lung substance and thus an increase in signal relative to the background. To reduce signal decay, ultrashort echo time (UTE) methods were developed to minimize the time between excitation and readout. Having been postulated a while ago, improved hardware and software now open up the possibility of achieving echo times shorter than 200 µs, increasing lung signal significantly by forestalling signal decay and more effectively using the few protons available. Such UTE techniques may not only improve structural imaging of the lung but also enhance functional imaging, including ventilation and perfusion imaging as well as quantitative parameter mapping. Because of accelerating progress in this field of lung MRI, the review at hand seeks to introduce some technical properties as well as to summarize the growing data from applications in humans and disease, which promise that UTE MRI will play an important role in the morphological and functional assessment of the lung in the near future., Key Points:   · Ultrashort echo time MRI is technically feasible with state-of-the-art scanner hardware.. · UTE MRI allows for CT-like image quality for structural lung imaging.. · Preliminary studies show improvements over conventional morphological imaging in lung cancer and airways diseases.. · UTE may improve sensitivity for functional processes like perfusion and tissue characterization.., Citation Format: · Wielpütz MO, Triphan SM, Ohno Y et al. Outracing Lung Signal Decay - Potential of Ultrashort Echo Time MRI. Fortschr Röntgenstr 2019; 191: 415 - 423., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background: The heterogeneous distribution of emphysema is a key feature of chronic obstructive pulmonary disease (COPD) patients that typically is evaluated using high-resolution chest computed tomography (HRCT). Oxygen-enhanced pulmonary magnetic resonance imaging (OEMRI) is a new method to obtain information regarding regional ventilation, diffusion, and perfusion in the lung without radiation exposure. We aimed to compare OEMRI with HRCT for the assessment of heterogeneity in COPD patients., Methods: Forty patients with stable COPD underwent quantitative HRCT, OEMRI, and pulmonary function tests, including arterial blood gas analysis. OEMRI was also performed on nine healthy control subjects. We measured the severity of emphysema (percent low attenuation volume; LAV%) in whole lungs and the standard deviations (SDs) of the LAV% values of 10 isovolumetric partitions (SD-LAV) as an index of cranial-caudal heterogeneity. Similarly, relative enhancement ratios of oxygen (RERs) in whole lungs from OEMRI and SD-RER were analyzed., Results: COPD patients showed a lower mean RER than control subjects (12.6% vs 22.0%, p<0.01). The regional heterogeneity of the RERs was not always consistent with the LAV distribution. Both the HRCT (LAV% and SD-LAV) and the OEMRI (RER and SD-RER) indices were significantly associated with the diffusion capacity (DLCO) and partial pressure of oxygen in arterial blood (PaO2). The PaO2 was associated only with the heterogeneity index of HRCT (SD-LAV) (R2 = 0.39); however, the PaO2 was associated with both the mean RER and heterogeneity (SD-RER) in the multivariate analysis (R2 = 0.38)., Conclusions: OEMRI-derived parameters were directly associated with oxygen uptake in COPD patients. Although the OEMRI-derived parameters were not identical to the HRCT-derived parameters, the cranial-caudal heterogeneity in HRCT or OEMRI was complementary to that in evaluations of oxygen uptake in the lungs. Functional imaging seems to provide new insights into COPD pathophysiology without radiation exposure., Competing Interests: None of the authors have any conflicts of interest to declare regarding the publication of this manuscript, except for Dr. Ohno and Dr. Togashi, who have research grants from Toshiba Medical Systems Corporation. This funding does not alter our adherence to PLOS ONE policies on sharing data and materials.

Since the clinical introduction of magnetic resonance imaging (MRI), the chest has been one of its most challenging applications, and many physicists and radiologists have tried since the 1980s to use MR for assessment of different lung diseases as well as mediastinal and pleural diseases. Since then, however, technical advances in sequencing, scanners, and coils, adaptation of parallel imaging techniques, utilization of contrast media, and development of postprocessing tools have been reported by many basic and clinical researchers. As a result, state-of-the-art thoracic MRI is now substituted for traditional imaging techniques and/or plays a complementary role in the management of patients with various chest diseases, and especially in the detection of pulmonary nodules and in thoracic oncology. In addition, MRI has continued to be developed to help overcome the limitations of computed tomography (CT) and nuclear medicine examinations. It can currently provide not only morphological, but also functional, physiological, pathophysiological, and molecular information at 1.5T with a gradual shift from 1.5T to 3T MR systems. In this review, we focus on these recent advances in MRI for pulmonary nodule detection and pulmonary nodule and mass evaluation by using noncontrast-enhanced and contrast-enhanced techniques as well as new molecular imaging methods such as chemical exchange saturation transfer imaging for a comparison with other modalities such as single or multidetector row CT, 18F-fluoro-2-deoxyglucose positron emission tomography (FDG-PET), and/or PET/CT., Level of Evidence: 4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1437-1458., (© 2018 International Society for Magnetic Resonance in Medicine.)

Background: To assess the impact of diabetes on restrictive and obstructive lung function impairment., Methods: This 5-year prospective study included 7524 participants aged 40-69years without lung function impairment at baseline who underwent a comprehensive medical check-up between April 2008 and March 2009 at Saku Central Hospital. Diabetes was defined by fasting plasma glucose ≥7.0mmol/l (126mg/dl), HbA1c≥6.5% (48mmol/mol), or a history of diabetes, as determined by interviews conducted by the physicians. Restrictive and obstructive lung function impairment were defined as forced vital capacity (FVC) <80% predicted and forced expiratory volume in 1s (FEV 1 ) to FVC ratio (FEV 1 /FVC) <0.70, respectively. Participants were screened until they developed restrictive or obstructive lung function impairment or until March 2014., Results: During the follow-up period, 171 and 639 individuals developed restrictive and obstructive lung function impairment, respectively. Individuals with diabetes had a 1.6-fold higher risk of restrictive lung function impairment than those without diabetes after adjusting for sex, age, height, abdominal obesity, smoking status, exercise habits, systolic blood pressure, HDL-cholesterol, log-transformed high-sensitivity C-reactive protein, and baseline lung function [multivariable-adjusted HR and 95% CI; 1.57 (1.04-2.36)]. In contrast, individuals with diabetes did not have a significantly higher risk of obstructive lung function impairment [multivariable-adjusted HR and 95% CI; 0.93 (0.72-1.21)]., Conclusion: Diabetes was associated with restrictive lung function impairment but not obstructive lung function impairment., (Copyright © 2017. Published by Elsevier Inc.)

Purpose: To evaluate the utility of three-dimensional (3D) lung motion on inspiratory and expiratory CT for pulmonary functional loss in smoking-related COPD in comparison with lung destruction and air trapping assessments., Method and Materials: Forty-four consecutive smokers and COPD patients prospectively underwent inspiratory and expiratory CT. A 3D motion vector map was generated from these CTs, and regional motion magnitudes were measured at the horizontal axis (X-axis), the ventrodorsal axis (Y-axis), and the craniocaudal axis (Z-axis). All mean magnitudes within the entire lung (MMLX, MMLY, and MMLZ) were normalized by expiratory CT lung volume. Moreover, CT-based functional lung volume (FLV) on inspiratory CT and air trapping lung volume (ATLV) on expiratory CT were assessed quantitatively. To evaluate the capability for pulmonary function loss assessment, all MMLs were correlated with pulmonary function tests. Then, discrimination analysis was performed to determine the concordance capability for clinical stage, and correct classification capabilities were compared by means of McNemar's test., Results: Multiple regression analysis showed MMLY (β=0.657, p<0.001) and FLV (β=0.375, p=0.019) were correlated with percentage of predicted forced expiratory volume in 1 second. Correct classification capabilities using patient characteristics and MMLs (68.2 (30/44)%) were significantly higher than those obtained by patient characteristics, FLV, and ATLV (54.5 (24/44)%), p=0.031)., Conclusion: 3D lung motion parameter assessment is useful for smoking-related COPD assessment as well as lung parenchymal destruction and/or air trapping evaluations., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

This review focuses on the state-of-the-art of the three major classes of gas contrast agents used in magnetic resonance imaging (MRI)-hyperpolarized (HP) gas, molecular oxygen, and fluorinated gas--and their application to clinical pulmonary research. During the past several years there has been accelerated development of pulmonary MRI. This has been driven in part by concerns regarding ionizing radiation using multidetector computed tomography (CT). However, MRI also offers capabilities for fast multispectral and functional imaging using gas agents that are not technically feasible with CT. Recent improvements in gradient performance and radial acquisition methods using ultrashort echo time (UTE) have contributed to advances in these functional pulmonary MRI techniques. The relative strengths and weaknesses of the main functional imaging methods and gas agents are compared and applications to measures of ventilation, diffusion, and gas exchange are presented. Functional lung MRI methods using these gas agents are improving our understanding of a wide range of chronic lung diseases, including chronic obstructive pulmonary disease, asthma, and cystic fibrosis in both adults and children., (© 2015 Wiley Periodicals, Inc.)

Purpose: To determine the capability and influence of the mathematical method on dynamic contrast-enhanced (CE-) perfusion area detector CT (ADCT) for early prediction of treatment response as well as progression free and overall survival (PFS and OS) of non-small cell lung cancer (NSCLC) patients treated with chemoradiotherapy., Materials and Methods: Sixty-six consecutive stage III NSCLC patients underwent dynamic CE-perfusion ADCT examinations, chemoradiotherapy and follow-up examinations. Response Evaluation Criteria in Solid Tumors (RECIST) criteria were used to divide all patients into responders and non-responders. Differences in each of the indices for all targeted lesions between measurements obtained 2 weeks prior to the first and the third course of chemotherapy were determined for all patients. ROC analyses were employed to determine the capability of perfusion indices as markers for distinguishing RECIST responders from non-responders. To evaluate their capability for early prediction of therapeutic effect, OS of perfusion index-based responders and non-responders were compared by using the Kaplan-Meier method followed by log-rank test., Results: Area under the curve (Az) for total perfusion by means of the dual-input maximum slope method was significantly larger than that of pulmonary arterial perfusion using the same method (p=0.007) and of perfusion with the single-input maximum slope method (p=0.007). Mean OS demonstrated significantly difference between responder- and non-responder groups for total perfusion (p=0.02)., Conclusion: Mathematical models have significant influence on assessment for early prediction of treatment response, disease progression and overall survival using dynamic CE-perfusion ADCT for NSCLC patients treated with chemoradiotherapy., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Background: Regional iodine distribution assessment on dual-energy computed tomography (DECT) has been suggested as useful for management of acute pulmonary thromboembolism (APTE) patients. However, no reported studies have made a direct comparison between quantitatively assessed DECT and right-to-left ventricular (RV/LV) ratio on CT for differentiation of right heart dysfunction (RHD) from non-right heart dysfunction (NRHD) in APTE patients., Purpose: To determine the capability of DECT for differentiation of RHD from NRHD in APTE patients., Material and Methods: Thirteen APTE patients underwent DECT and echocardiography at onset of APTE. Patients were divided into RHD (n = 7) and NRHD (n = 6) groups based on echocardiography. A normalized lung perfused blood volume map was generated, and two kinds of overall perfusion (OP) index were determined, one placed over each lung field (OP index A) and as the average from six regions of interest (ROIs) placed over each lung field (OP index B). The heterogeneity index was also determined as the standard deviation for the six ROIs. RV/LV ratio evaluations were also performed. To assess differences between the two groups, each index was statistically compared with the Mann-Whitney U test. The receiver-operating curve-based positive test was then performed to determine the feasible threshold value for dividing patients into the two groups. Finally, differentiation capabilities of the indexes were compared using McNemar's test., Results: Significant differences between the two groups were found for both OP indexes and RV/LV ratio (P < 0.05). For each of the feasible threshold values, accuracy of each OP index with and without RV/LV ratio was better than that of the RV/LV ratio., Conclusion: Quantitative DECT has good potential for differentiation of APTE patients with and without right heart dysfunction., (© The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.)

Rationale and Objectives: To evaluate paired inspiratory/expiratory computed tomography (CT; iCT/eCT) and deformable image registration for quantitative and qualitative assessment of airflow limitation in smokers., Materials and Methods: Paired iCT/eCT images acquired from 35 smokers (30 men and 5 women) were coregistered and subtraction images (air trapping CT images [aCT]) generated. To evaluate emphysema quantitatively, the percentage of low-attenuation volume (LAV%) on iCT was calculated at -950 HU, as were mean and kurtosis on aCT for quantitative assessment of air trapping. Parametric response maps of emphysema (PRMe) and of functional small airways disease (PRMs) were also obtained. For qualitative evaluation of emphysema, low-attenuation areas on iCT were scored by consensus of two radiologists using Goddard classification. To assess air trapping qualitatively, the degree of air trapping on aCT was scored. For each quantitative and qualitative index, the Spearman rank correlation coefficient for forced expiratory flow in 1 second was calculated, and differences in correlation coefficients were statistically tested., Results: The correlation coefficients for the indices were as follows: mean on aCT, 0.800; kurtosis on aCT, -0.726; LAV%, -0.472; PRMe, -0.570; PRMs, -0.565; addition of PRMe and PRMs, -0.653; emphysema score, -0.502; air trapping score, -0.793. The indices showing significant differences were as follows: mean on aCT and addition of PRMe and PRMs (P = 1.43 × 10(-8)); air trapping score and emphysema score (P = .0169)., Conclusions: Air trapping images yielded more accurate quantitative and qualitative evaluation of airflow limitation than did LAV%, PRMe, PRMs, and Goddard classification., (Copyright © 2015 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the advantages of iterative reconstruction for quantitative computed tomography (CT) analysis of pulmonary emphysema., Materials and Methods: Twenty-two patients with pulmonary emphysema underwent chest CT imaging using identical scanners with three different tube currents: 240, 120, and 60 mA. Scan data were converted to CT images using Adaptive Iterative Dose Reduction using Three Dimensional Processing (AIDR3D) and a conventional filtered-back projection mode. Thus, six scans with and without AIDR3D were generated per patient. All other scanning and reconstruction settings were fixed. The percent low attenuation area (LAA%; < -950 Hounsfield units) and the lung density 15th percentile were automatically measured using a commercial workstation. Comparisons of LAA% and 15th percentile results between scans with and without using AIDR3D were made by Wilcoxon signed-rank tests. Associations between body weight and measurement errors among these scans were evaluated by Spearman rank correlation analysis., Results: Overall, scan series without AIDR3D had higher LAA% and lower 15th percentile values than those with AIDR3D at each tube current (P<0.0001). For scan series without AIDR3D, lower tube currents resulted in higher LAA% values and lower 15th percentiles. The extent of emphysema was significantly different between each pair among scans when not using AIDR3D (LAA%, P<0.0001; 15th percentile, P<0.01), but was not significantly different between each pair among scans when using AIDR3D. On scans without using AIDR3D, measurement errors between different tube current settings were significantly correlated with patients' body weights (P<0.05), whereas these errors between scans when using AIDR3D were insignificantly or minimally correlated with body weight., Conclusion: The extent of emphysema was more consistent across different tube currents when CT scans were converted to CT images using AIDR3D than using a conventional filtered-back projection method.

Purpose: To evaluate the effects of adaptive iterative dose reduction using 3D processing (AIDR 3D) for quantification of two measures of emphysema: percentage of low-attenuation volume (LAV%) and size distribution of low-attenuation lung regions., Method and Materials: Fifty-two patients who underwent standard-dose (SDCT) and low-dose CT (LDCT)were included. SDCT without AIDR 3D, LDCT without AIDR 3D, and LDCT with AIDR 3D were used for emphysema quantification. First, LAV% was computed at 10 thresholds from −990 to −900 HU. Next, at the same thresholds, linear regression on a log–log plot was used to compute the power law exponent (D)for the cumulative frequency-size distribution of low-attenuation lung regions. Bland–Altman analysis was used to assess whether AIDR 3D improved agreement between LDCT and SDCT for emphysema quantification of LAV% and D., Results: The mean relative differences in LAV% between LDCT without AIDR 3D and SDCT were 3.73%–88.18% and between LDCT with AIDR 3D and SDCT were −6.61% to 0.406%. The mean relative differences in D between LDCT without AIDR 3D and SDCT were 8.22%–19.11% and between LDCT with AIDR3D and SDCT were 1.82%–4.79%. AIDR 3D improved agreement between LDCT and SDCT at thresholds from −930 to −990 HU for LAV% and at all thresholds for D., Conclusion: AIDR 3D improved the consistency between LDCT and SDCT for emphysema quantification of LAV% and D., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Rationale and Objectives: The purpose of this study was to analyze the relationship between airflow limitation and two types of computed tomography (CT) measurements: expiratory/inspiratory (E/I) ratio and E/I difference of percentage of low-attenuation lung regions (LAA%)., Materials and Methods: Thirty patients who underwent inspiratory and expiratory CT scans were included in this study. The CT data were used to calculate the LAA% E/I ratio and E/I difference. Other types of CT measurements were also obtained, including the E/I ratio and E/I difference of lung volume, mean lung density, standard deviation, skewness, and kurtosis. LAA% was calculated at 20 thresholds (-990 to -800 HU). Pearson's correlation between the measurements and forced expiratory flow in 1 second was used to determine the efficacy of LAA% E/I ratio and E/I difference. P values of <5.88 × 10⁻⁵ were considered statistically significant with Bonferroni correction., Results: The LAA% E/I ratio and E/I difference significantly correlated with forced expiratory flow in 1 second. The best correlation coefficient for the LAA% E/I ratio was -0.699 (P = 1.75 × 10⁻⁵) and for the LAA% E/I difference was -0.723 (P = 6.53 × 10⁻⁶). The best correlation coefficient for the LAA% E/I difference was stronger than that for the other types of CT measurements., Conclusions: The LAA% E/I ratio and E/I difference significantly correlated with airflow limitation in chronic obstructive pulmonary disease., (Copyright © 2014 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the influence of ultrashort TE (UTE) intervals on pulmonary magnetic resonance imaging (MRI) with UTEs (UTE-MRI) for pulmonary functional loss assessment and clinical stage classification of smokers., Materials and Methods: A total 60 consecutive smokers (43 men and 17 women; mean age 70 years) with and without COPD underwent thin-section multidetector row computed tomography (MDCT), UTE-MRI, and pulmonary functional measurements. For each smoker, UTE-MRI was performed with three different UTE intervals (UTE-MRI A: 0.5 msec, UTE-MRI B: 1.0 msec, UTE-MRI C: 1.5 msec). By using the GOLD guidelines, the subjects were classified as: "smokers without COPD," "mild COPD," "moderate COPD," and "severe or very severe COPD." Then the mean T2* value from each UTE-MRI and CT-based functional lung volume (FLV) were correlated with pulmonary function test. Finally, Fisher's PLSD test was used to evaluate differences in each index among the four clinical stages., Results: Each index correlated significantly with pulmonary function test results (P < 0.05). CT-based FLV and mean T2* values obtained from UTE-MRI A and B showed significant differences among all groups except between "smokers without COPD" and "mild COPD" groups (P < 0.05)., Conclusion: UTE-MRI has a potential for management of smokers and the UTE interval is suggested as an important parameter in this setting., (Copyright © 2013 Wiley Periodicals, Inc.)

Objective: The purpose of this study was to determine the utility of adaptive iterative dose reduction using 3D processing (AIDR 3D) for image noise reduction and assessment of radiologic findings obtained with reduced- and low-dose chest CT in patients with various pulmonary diseases., Subjects and Methods: Chest CT examinations at three different tube current settings and using 16- and 64-MDCT scanners were performed for 37 patients. Standard-dose (150 mAs) data were reconstructed as thin-section CT without AIDR 3D, and low-dose (25 mAs) and reduced-dose (50 mAs) data were reconstructed as thin-section CT without and with AIDR 3D. To compare image quality, image noises at all CT doses were quantitatively assessed by region of interest measurements. For comparison of radiologic finding assessments, likelihoods of occurrence of emphysema, ground-glass opacity, reticular opacity, bronchiectasis, honeycomb pattern, and nodules were evaluated on a 5-point scale. Then, image noise and agreements of radiologic findings between standard-dose CT and others were statistically evaluated., Results: The image quality scores of reduced- and low-dose CT without AIDR 3D were significantly lower than those of both protocols with AIDR 3D and standard-dose CT (p<0.05). All intermethod agreements for emphysema, ground-glass opacity, bronchiectasis, honeycomb pattern, and nodules, except for those observed on low-dose CT without AIDR 3D, were almost perfect (κ>0.81)., Conclusion: AIDR 3D is useful for image noise reduction and assessment of radiologic findings obtained with reduced- and low-dose CT for patients with various pulmonary diseases.

Rationales and Objectives: To evaluate the image quality of 320-row wide-volume (WV) computed tomography (CT) scans in comparison with 64-row helical scans for the lung., Materials and Methods: The Institutional Review Board of each institution approved this prospective, multicenter study and informed consent was obtained. A total of 73 subjects underwent two types of chest CT, including 320-row WV scans and 64-row helical scans. Both scans used the same tube voltage, tube current, exposure time setting, and slice thickness. The helical scans were not electrocardiogram (ECG)-gated. For the WV scans, prospective ECG-gating was used for 38 subjects, whereas the other 35 subjects did not have ECG-gating. Using a 5-point scale from 1 (nondiagnostic) to 5 (excellent), three blinded observers independently evaluated image quality for five lobes and the lingula. The differences in the scores between WV scans and helical scans were compared using Wilcoxon's signed-rank test., Results: The WV scans with ECG-gating had significantly higher scores than 64-row helical scans for all lobes and lingula (right lower lobe, P < .01; other lobes and lingula, P < .0001, respectively). The 320-row WV scans without ECG-gating also had significantly higher scores than 64-row helical scans (P < .05), except for nonsignificant differences for the left upper lobe., Conclusions: Lung image quality of ECG-gated WV scans, which do not require any additional radiation exposure, is better than that of non-ECG-gated 64-row helical scans. Non-ECG-gated 320-row WV scans are comparable or slightly superior to non-ECG-gated 64-row helical scans., (Copyright © 2012 AUR. Published by Elsevier Inc. All rights reserved.)

Purpose: The purpose of this study was to evaluate in vivo the influence of inversion pulse slice selectivity on oxygen-enhanced magnetic resonance imaging (MRI)., Materials and Methods: Thirteen healthy volunteers were studied with a two-dimensional cardiac- and respiratory-gated adiabatic inversion-recovery half-Fourier single-shot turbo spin-echo (HASTE) sequence with either slice-selective or non-slice-selective inversion recovery (IR) pulse at inversion times increasing from 300 to 1400 ms. The signal-to-noise ratio (SNR) at every inversion time (TI), real signal difference (ΔSI), and relative enhancement ratio of lung parenchyma at TI ≥ 800 ms were statistically compared for oxygen-enhanced and non-oxygen-enhanced MR images with slice-selective or non-slice-selective IR pulses., Results: The SNRs of acquisitions with slice-selective IR pulses were significantly higher than those of non-slice-selective IR pulses (P < 0.05). At TI 800 ms, the ΔSI of lung parenchyma on IR-HASTE images with slice-selective inversion pulse type was significantly higher than on that with the non-slice-selective type (P < 0.05). Relative enhancement ratios of the slice-selective IR pulses were significantly lower than those of non-slice-selective IR pulses at TIs between 800 and 1400 ms (P < 0.05)., Conclusion: Slice selectivity of inversion pulse type affects oxygen-enhanced MRI in vivo.

Purpose: The purpose of this study was to determine the utility of three-dimensional (3D) automatic exposure control (AEC) for low-dose CT examination in a chest phantom study., Materials and Methods: A chest CT phantom including simulated focal ground-glass opacities (GGOs) and nodules was scanned with a 64-detector row CT with and without AEC. Performance of 3D AEC included changing targeted standard deviations (SDs) of image noise from scout view. To determine the appropriate targeted SD number for identification, the capability of overall identification with the CT protocol adapted to each of the targeted SDs was compared with that obtained with CT without AEC by means of receiver operating characteristic analysis., Results: When targeted SD values equal to or higher than 250 were used, areas under the curve (Azs) of nodule identification with CT protocol using AEC were significantly smaller than that for CT protocol without AEC (p < 0.05). When targeted SD numbers at equal to or more than 180 were adapted, Azs of CT protocol with AEC had significantly smaller than that without AEC (p < 0.05)., Conclusion: This phantom study shows 3D AEC is useful for low-dose lung CT examination, and can reduce the radiation dose while maintaining good identification capability and good image quality., (Copyright © 2009 Elsevier Ireland Ltd. All rights reserved.)

Nonuniform disruption of lung architecture is usually assessed by CT, which carries potential radiation risk. Here we report our use of a three-dimensional ultrashort echo time MR method to image the lungs of normal mice at different positive end-expiratory pressures in a 3-T clinical MR system. The ultrashort echo time sequence in conjunction with a projection acquisition of the free induction decay could reduce the echo time to 100 μsec and provide a more inherent MR signal intensity from the lung parenchyma, which is usually invisible due to its short T*(2) in conventional MRI methods. The signal intensity and T*(2) was reduced as the positive end-expiratory pressure became higher. Further, these parameters were highly correlated to the changes in lung volume (% lung expansion). The results indicated that the MR signal acquired at ultrashort echo time in the lung parenchyma represents interstitial tissue density including blood. The capability of acquiring sufficient MR signal would have implications for the direct assessment of parenchymal architecture in the lung. Therefore, ultrashort echo time imaging may have the potential to assist detection of early and localized pathological destruction of lung tissue architecture observed in various pulmonary disorders such as emphysema without incurring the risks of radiation exposure., (Copyright © 2010 Wiley-Liss, Inc.)

Purpose: To investigate the utility of ultra-short echo time (UTE) sequence as pulmonary MRI to detect non-uniform disruption of lung architecture that is typical of emphysema., Materials and Methods: MRI of the lungs was conducted with a three-dimensional UTE sequence in transgenic mice with severe emphysema and their wild-type littermates in a 3 Tesla clinical MR system. Measurements of the signal intensity (SI) and transverse relaxation time (T2*) of the lung parenchyma were performed with various echo times (TEs) ranging from 100 micros to 2 ms., Results: Much higher SI of the lung parenchyma was observed at an UTE of 100 micros compared with longer TEs. The emphysematous lungs had reduced SIs and T2* than the controls, in particular at end-expiratory phase. The results suggested that both SI and T2* in lung parenchyma measured with the method represent fractional volume of lung tissue., Conclusion: The UTE imaging provided MR signal from the lung parenchyma. Moreover, the UTE sequence was sensitive to emphysematous changes and may provide a direct assessment of lung parenchyma. UTE imaging has the potential to assist detection of localized pathological destruction of lung tissue architecture in emphysema., (2010 Wiley-Liss, Inc.)

Objective: The aim of the study was to evaluate the diagnostic performance of diffusion-weighted imaging (DWI) for detection and subtype classification in pulmonary adenocarcinomas through comparison with short TI inversion recovery turbo spin-echo imaging sequence (STIR)., Methods: Thirty-two patients (mean age, 65.2 years) with 33 adenocarcinomas (mean diameter, 27.6 mm) were enrolled in this study. The detection rates of both sequences were compared. The ADC values on DWI and the contrast ratio (CR) between cancer and muscle on STIR were measured and those were compared across subtype classifications. Finally, ROC-based positive tests were performed to differentiate subtype classifications, and differentiation capabilities were compared., Results: The DWI detection rate [85% (28/33)] was significantly lower than that of STIR [100% (33/33), P < 0.05]. The ADC values showed no significant difference regarding subtype classification; however, the CRs of bronchio-alveolar carcinomas (BACs) were significantly lower than those of other types (P < 0.05). When threshold values for differentiating BACs from others were adapted, the sensitivity and accuracy of DWI were significantly lower than those of STIR (P < 0.05). For differentiating adenocarcinomas with mixed subtypes from those with no BA component, there were no significant differences between the two sequences., Conclusion: STIR is more sensitive for detection and subtype classification than DWI.

Objective: The purpose of this study was to determine the effectiveness of a 3D adaptive raw-data filter in improving image quality and the role of the filter in radiation dose reduction in lung CT., Materials and Methods: Fifty-eight chest CT examinations were performed with a 16-MDCT scanner. Two acquisitions were performed with different tube current-exposure time settings (50 and 150 mAs, 120 kVp). Four series of lung images were prepared from two sets of raw data with and without application of a 3D adaptive filter (50 mAs, 50 mAs with filter, 150 mAs, 150 mAs with filter). Three blinded readers using a 5-point scale from 1 (nondiagnostic) to 5 (excellent) independently evaluated image quality in five lobes and the lingula. A set of images was considered acceptable when scores in all six regions were 3 (acceptable) or higher. The SD of attenuation was calculated in 24 regions of interest., Results: The overall mean image quality scores were 3.09, 3.53, 4.02, and 4.38 for the 50 mAs, 50 mAs with filter, 150 mAs, and 150 mAs with filter sets, respectively. Scores were significantly better with filter application (p < 0.001). A significant decrease in SD of attenuation was observed with filter application (p < 0.001). Among the respective series of images, 18, 52, 50, and 58 sets were judged acceptable with no significant difference in acceptability between images obtained at 50 mAs with a filter and at 150 mAs (p = 0.72). With filter application, the acceptability of 50-mAs images became comparable with that of 150-mAs images, making dose reduction to 50 mAs practical., Conclusion: Use of a 3D adaptive raw-data filter improved the quality of lung images, making dose reduction to 50 mAs attainable with use of the filter.

Recent development of MR techniques has overcome many problems, such as susceptibility artifacts or motion artifact, allowing both static and dynamic MR lung imaging and providing quantitative information of pulmonary function, including perfusion, ventilation, and respiratory motion. Dynamic contrast-enhanced MR perfusion imaging is suitable for the evaluation of angiogenesis of pulmonary solitary nodules. (129)Xe MR imaging is potentially a robust technique for the evaluation of various pulmonary function and may replace (3)He. The information provided by these new MR imaging methods is proving useful in research and in clinical applications in various lung diseases.

Purpose: The purpose of our study was to assess the influence of prolonged apnea and administration of oxygen on pulmonary hemodynamics during breath holding (BH) by using velocity-encoded MR imaging combined with the SENSE technique (velocity MRI)., Materials and Methods: Ten healthy male volunteers underwent velocity MRI during BH with and without O(2) inhalation. All velocity MRI data sets were obtained continuously with the 2D cine phase-contrast method during a single BH period. The data were then divided into three BH time phases as follows: first, second and third. To evaluate the influence of prolonged apnea on hemodynamics, stroke volume (SV) and maximal change in flow rate during ejection (MCFR) of second and third phases were statistically compared with those of first phase by using the ANOVA followed by Turkey's HSD multiple comparison test. To assess the influence of O(2) on hemodynamics, SV and MCFR with or without O(2) were compared by the paired t-test. To assess the measuring agreement of hemodynamic indices during prolonged breath holding, Bland-Altman's analysis was performed., Results: Prolonged apnea had no significant influence on SV and MCFR regardless of administration of O(2) (p>0.05). Mean MCFR for all phases was significantly lower with administration of O(2) than without (p<0.05). The limits of agreement for MCFR with O(2) were smaller than without., Conclusion: O(2) inhalation modulated maximal change in flow rate during ejection, and did not influence stroke volume during breath holding. Influence of O(2) inhalation should be considered for MR measurements of pulmonary hemodynamics during breath holding.

1. Flavonoids are naturally occurring compounds that possess anti-allergic, anti-inflammatory, antiproliferative and anti-oxidant properties. In the present study, we investigated whether the flavonoid narirutin could reduce airway inflammation in ovalbumin (OVA)-sensitized/challenged NC/Nga mice, a model of allergic eosinophilic airway inflammation. 2. Mice were initially immunized intraperitoneally with OVA on Days 0 and 7 and then challenged with inhaled OVA on Days 14, 15 and 16. In addition, some mice received narirutin orally at doses of 0.1, 1 or 10 mg/kg bodyweight daily on Days 7-16. 3. At 10 mg/kg, but not 0.1 or 1 mg/kg, narirutin significantly diminished OVA-induced airway inflammation caused by infiltration of lung tissue with inflammatory and mucus-producing cells, as well as reduced eosinophil counts in the peripheral blood and bronchoalveolar lavage fluid (BALF), interleukin (IL)-4 levels in BALF and IgE levels in serum. 4. The mechanism of the anti-inflammatory effect of narirutin are likely to be associated with a reduction in the OVA-induced increases of IL-4 and IgE in a murine model of allergic eosinophilic airway inflammation. These findings suggest that narirutin may be an effective new tool in the treatment of bronchial asthma.

Porcine pancreatic elastase (PPE), which induces emphysema via apoptosis, was administered to wild-type and Fas-deficient (lpr) mice. On days 3 and 28 after administration, the mean linear intercepts within lung tissues were significantly higher in PPE-treated wild-type and lpr mice than in control mice, though there were no significant differences between the PPE-treated groups. Likewise, the numbers of TUNEL-positive cells were increased in the lungs of PPE-treated wild-type and lpr mice, and again the effect was similar in the two PPE-treated groups. These findings suggest that apoptosis associated with PPE-induced emphysema is not mediated via the Fas/Fas-ligand pathway.

The authors investigated whether autologous bone marrow mononuclear cell (BMC) transplantation via the left and right main bronchi would mitigate elastase-induced pulmonary emphysema in rabbits. Four weeks after elastase administration, rabbits also receiving BMCs showed significantly better pulmonary function (FVC, FEV100, FEVPEF) and smaller alveolar airspaces, as indicated by a smaller mean linear intercept, than those receiving porcine pancreatic elastase (PPE) (200 U/kg) alone via the left and right main bronchi. BMCs also significantly reduced cell counts in bronchoalveolar lavage fluid, the incidence of apoptotic (TUNEL-positive) cells and matrix metalloproteinase (MMP)-2 expression, while increasing numbers of proliferative (Ki-67-positive) cells. Thus, BMCs may inhibit the progression to emphysema by attenuating inflammation, MMP-2 expression, and apoptosis, while enhancing alveolar cell proliferation.

Purpose: To determine the clinical utility of thin-section multiplanar reformats (MPRs) from multidetector-row CT (MDCT) data sets for assessing the extent of regional tumors in non-small cell lung cancer (NSCLC) patients., Materials and Methods: Sixty consecutive NSCLC patients, who were considered candidates for surgical treatment, underwent contrast-enhanced MDCT examinations, surgical resection and pathological examinations. All MDCT examinations were performed with a 4-detector row computed tomography (CT). From each raw CT data set, 5mm section thickness CT images (routine CT), 1.25 mm section thickness CT images (thin-section CT) and 1.25 mm section thickness sagittal (thin-section sagittal MPR) and coronal images (thin-section coronal MPR) were reconstructed. A 4-point visual score was used to assess mediastinal, interlobar and chest wall invasions on each image set. For assessment of utility in routine clinical practice, mean reading times for each image set were compared by means of Fisher's protected least significant difference (PLSD) test. A receiver operator characteristic (ROC) analysis was performed to determine the diagnostic capability of each of the image data sets. Finally, sensitivity, specificity and accuracy of the reconstructed images were compared by McNemar test., Results: Mean reading times for thin-section sagittal and coronal MPRs were significantly shorter than those for routine CT and thin-section CT (p<0.05). Areas under the curve (Azs) showing interlobar invasion on thin-section sagittal and coronal MPRs were significantly larger than that on routine CT (p=0.03), and the Az on thin-section sagittal MPR was also significantly larger than that on routine CT (p=0.02). Accuracy of chest wall invasion by thin-section sagittal MPR was significantly higher than that by routine CT (p=0.04)., Conclusion: Thin-section multiplanar reformats from multidetector-row CT data sets are useful for assessing the extent of regional tumors in non-small cell lung cancer patients.

Purpose: To assess regional differences in quantitative pulmonary perfusion parameters, i.e., pulmonary blood flow (PBF), mean transit time (MTT), and pulmonary blood volume (PBV) in the entire lung on a pixel-by-pixel basis in normal volunteers and pulmonary hypertension patients., Materials and Methods: Three-dimensional ultrafast dynamic contrast-enhanced MR imaging was performed in 15 normal volunteers and 25 patients with pulmonary hypertension. From the signal intensity-time course curves, PBF, MTT and PBV maps were generated using deconvolution analysis, indicator dilution theories, and the central volume principle, on a pixel-by-pixel basis. From pulmonary perfusion parameter maps of normal volunteers and pulmonary hypertension patients, regional PBF, MTT, and PBV were statistically evaluated., Results: Regional PBF, MTT, and PBV showed significant differences in the gravitational and isogravitational directions (P < 0.05). The quantitative pulmonary perfusion parameter maps demonstrated significant differences between normal volunteers and pulmonary hypertension patients (P < 0.05)., Conclusion: Three-dimensional ultrafast dynamic contrast-enhanced MR imaging is feasible for the assessment of regional quantitative pulmonary perfusion parameters in the entire lung on a pixel-by-pixel basis in normal volunteers and pulmonary hypertension patients., (Copyright 2004 Wiley-Liss, Inc.)

Purpose: To improve the image quality of pulmonary magnetic resonance (MR) imaging using an ultra-short inter-echo spacing half-Fourier single shot rapid acquisition with relaxation enhancement (USHA-RARE) sequence., Materials and Methods: Pulmonary MR images were acquired by USHA-RARE sequence with various inter-echo spacings. The sequence parameters were as follows: repetition time (TR)/effective TE: infinite/39-41 msec; section thickness: 10 mm; acquisition matrix: 128 x 128; field of view: 450 x 450 mm. Inter-echo spacing varied (2.5 msec, 3.0 msec, 3.5 msec, 4.0 msec, 4.5 msec, 5.0 msec), and the respective phase-encoding steps were 80, 77, 75, 74, 73, and 72. Signal-to-noise ratios (SNRs), the signal ratios between lung and fat (lung-to-fat ratio: LFRs), and the signal ratios between the lung and the serratus anterior muscle (lung-to-muscle ratio: LMRs) of each inter-echo spacing were calculated, and statistically evaluated., Results: The SNRs at inter-echo spacings of < or = 3.0 msec were significantly higher than those > or = 4.0 msec (P < 0.05). The LFRs and LMRs at inter-echo spacing < or = 3.0 msec were significantly higher than those > or = 4.0 msec (P < 0.05)., Conclusion: USHA-RARE sequence does improve signal intensity from the lung., (Copyright 2004 Wiley-Liss, Inc.)

Objective: The aim of our study was to determine the utility of time-resolved contrast-enhanced MR angiography combined with sensitivity encoding (SENSE) for patients with pulmonary embolism. SUBJECTS AND METHODS. Forty-eight consecutive patients (26 men and 22 women; age range, 27-73 years; mean age, 55 years) with suspected pulmonary embolism underwent chest radiography, contrast-enhanced MDCT, MR angiography with SENSE, ventilation-perfusion scintigraphy, and pulmonary angiography. MR angiography with SENSE was performed using IV administration of gadolinium contrast medium with a 3D turbo field-echo pulse sequence (TR/TE, 4.0/1.2; flip angle, 30 degrees ) on a 1.5-T scanner. Capabilities of diagnosing pulmonary embolism using MR angiography (data set A), contrast-enhanced MDCT (data set B), contrast-enhanced MDCT with MR angiography (data set C), ventilation-perfusion scintigraphy (data set D), and contrast-enhanced MDCT with ventilation-perfusion scintigraphy (data set E) were determined by receiver operating characteristic analysis, using the results of pulmonary angiography as the reference standard. The diagnostic capability of each data set was analyzed on a per-vascular zone and a per-patient basis with the McNemar test., Results: Sensitivity and specificity of data set A were 83% and 97%, respectively, on a per-vascular zone basis and 92% and 94%, respectively, on a per-patient basis. Specificity and accuracy of data set A were significantly higher than those of data set D on a per-patient basis (p < 0.05)., Conclusion: Time-resolved MR angiography with SENSE is effective for the diagnosis of pulmonary embolism.

Objective: The purpose of this study was to determine the capability of dynamic perfusion MRI as an alternative to pulmonary perfusion scintigraphy for prediction of postoperative lung function in patients with lung cancer. SUBJECTS AND METHODS. Sixty patients with lung cancer (35 men, 25 women) underwent dynamic perfusion MRI, perfusion scintigraphy, and preoperative and postoperative pulmonary function tests (forced expiratory volume in 1 sec [FEV(1)]). Perfusion MRIs were obtained with a 3D turbo field-echo sequence (TR/TE, 2.7/0.6; flip angle, 40 degrees; matrix, 128 x 96) using a 1.5-T scanner. Regional blood flow was calculated from the signal intensity-time curves after bolus injection of contrast medium on MRI (Q(MRI)) and uptake ratios of radioisotope on perfusion scintigraphy (Q(PS)). Postoperative lung functions predicted by MRI (FEV(1,MRI)) and perfusion scintigraphy (FEV(1,PS)) were calculated from preoperative FEV(1) and regional Qs. To determine the capability of MRI as an alternative to scintigraphy, we evaluated correlations and the limits of agreement between predicted FEV(1,MRI) and postoperative FEV(1) and between predicted FEV(1,PS) and postoperative FEV(1)., Results: The correlation coefficient of postoperative FEV(1) with FEV(1,MRI) (r = 0.93, p < 0.0001) was better than that with FEV(1,PS) (r = 0.89, p < 0.0001). The limits of agreement between postoperative FEV(1) and predicted FEV(1,MRI) (0.9% +/- 10.4%) were smaller than those between postoperative FEV(1) and predicted FEV(1,PS) (2.1% +/- 13.2%)., Conclusion: Dynamic perfusion MRI is a feasible alternative to pulmonary perfusion scintigraphy for predicting postoperative lung function in patients with lung cancer.

Magnetic resonance imaging has been relatively underused for clinical application in the lung; however, developments in magnetic resonance perfusion imaging using contrast agents and spin labeling techniques have shown significant potential for clinical application in lung perfusion. This article reviews the recent publications on magnetic resonance pulmonary perfusion.

Summary: Oxygen-enhanced magnetic resonance (MR) ventilation imaging is a new technique, and the full extent of its physiologic significance has not been elucidated. This review article includes (1) theory of oxygen enhancement; (2) respiratory physiology; (3) oxygen-enhanced MR imaging (MRI) sequence design; (4) basic study of oxygen-enhanced MRI in animal models and humans; (5) clinical study of oxygen-enhanced MRI; and (6) merits and demerits of the technique in comparison with hyperpolarized noble gas MR ventilation imaging. Oxygen-enhanced MRI provides not only ventilation-related information but also respiration-related information. Although application of oxygen-enhanced MR ventilation imaging to patients with pulmonary diseases has been limited, oxygen-enhanced MRI offers the possibility of demonstrating regional pulmonary function and substituting for nuclear medicine ventilation-perfusion study, when combined with MR perfusion imaging. We believe that further basic studies and clinical applications of this new technique will define the real significance of oxygen-enhanced MR ventilation imaging in the future of pulmonary functional imaging and its usefulness for diagnostic radiology.

In this study, pulmonary MR angiography (MRA) using a tailored coil at 4 Tesla in conjunction with an intravenous injection of contrast agent is described. Three-dimensional gradient-echo images were obtained during the intravenous injection of 0.05, 0.1, and 0.2 mmol/kg body weight of gadodiamide to investigate the signal enhancement effect of the contrast agent in pulmonary arteries qualitatively and quantitatively. In the qualitative analysis, the subsegmental branches were visualized on every dose. In the quantitative analysis, the average contrast-to-noise ratios (CNRs) of the main pulmonary arteries increased in a dose-dependent manner. However, the CNRs of segmental arteries did not increase as the dose of contrast agent increased, as observed at 1.5 Tesla MRI. These observations demonstrate the feasibility of delineating the pulmonary vasculature using a contrast agent; however, our results also suggest possible high-field-related disabilities that need to be overcome before high-field (> or =4 Tesla) MRI can be used to full advantage., (Copyright 2001 Wiley-Liss, Inc.)

Rationale and Objectives: The authors performed this study to evaluate the spatial resolution of refraction imaging performed with synchrotron radiation (SR) on 2-mm-thick sections of excised normal human lung., Materials and Methods: Refraction images of specimens from a normal human lung were obtained with 19 keV, a 5-second exposure time, and a 2.4 x 2.4-cm field of view. The specimen-detector distance was 83 cm., Results: Structures of secondary pulmonary lobule consisting of pulmonary arteriole, terminal bronchiole, air sac, and venules in the interlobular septum in normal lung were clearly illustrated on refraction images obtained with SR. The imaging findings showed good correlation with those from histologic examination. The spatial resolution of the refraction images was approximately 10-30 microm, as measured with light microscopic analysis of specimens stained with hematoxylin-eosin., Conclusion: With refinement, this technique may have some practical purpose for diagnosing lung disease in vivo.

An understanding of fine normal lung morphology is important for effective pulmonary functional imaging. The lung specimens must be inflated. These include (a) unfixed, inflated lung specimen, (b) formaldehyde fixed lung specimen, (c) fixed, inflated dry lung specimen, and (d) histology specimen. Photography, magnified view, radiograph, computed tomography, and histology of these specimens are demonstrated. From a standpoint of diagnostic imaging, the main normal lung structures consist of airways (bronchi and bronchioles), alveoli, pulmonary vessels, secondary pulmonary lobules, and subpleural pulmonary lymphatic channels. This review summarizes fine radiologic normal lung morphology as an aid to effective pulmonary functional imaging.

It is well revealed that activation of macrophages stimulated by endotoxin resulted in induction of nitric oxide synthase which catalyze nitric oxide (NO) formation from L-arginine. Consequently, blood concentrations of NO2-/NO3- (NOx-) are shown to increase. We studied on pharmaco/toxicokinetics of NOx- in serum and principal organs in Wistar male rats after i.p. administrations of LPS and NaNO3. The serum levels of NOx- at 1 h and 6 h after nitrate administration (10 mg/kg, i.p.) were 240 and 120 microM, respectively. Tissue levels of NOx- in lung, liver and kidneys were ca.1/2 of the serum level. Those levels in spleen and brain were ca.1/4 and 1/10 of the serum level, respectively. The correlation of NOx- levels in serum and these 5 organ tissues between 1 h and 6 h after administration of nitrate was r = 0.992 suggesting no specific accumulation of NOx- in these organs. The serum level of NOx- at 18 h after LPS treatment (1 mg/kg, i.p.) was 430 microM. The correlation of NOx- levels in serum and 5 organ tissues between LPS and nitrate administrations was shown to be r = 0.851. NOx- levels of serum, lung, kidneys and brain showed good correlation but liver and spleen showed out of the correlation. The liver tissue level of NOx- after LPS treatment was low compared with the expected value from the serum level. The reason may be explained partially by the liver weight increase and the liver toxicity with increased GPT and gamma-GT levels due to LPS. Contrary to this, NOx- level of spleen tissue after LPS treatment was more than 2-fold compared with the expected value from the serum level suggesting NO formation in the spleen. This was supported by the markedly high concentration (73.2 nmol/g tissue) of NO2- in the spleen tissue. NO2- levels in lung (34.5 nmol/g tissue) and brain (14.3) were also found to be significantly high after stimulation with LPS suggesting NO formation in these organs. Increased formation of NO2- in these organs by LPS stimulation suggests the formation of active nitrogen oxides such as N2O3 which is an effective nitrosating agent in non-acidic conditions in vivo.

Three patients with non-Hodgkin's lymphoma (NHL) involving the lung or chest wall are reported. All patients had tuberculous pleuritis or received artificial pneumothorax for pulmonary tuberculosis 30 years or more previously. The NHL of these patients developed in or close to the thickened pleura. Histologic examination showed diffuse large cell type (LSG classification) in all cases. Lymphomas of all cases were considered to have originated from B-cell lineage because their neoplastic cells expressed B1 (CD20) antigens. In no case the tumors were resectable, and chemotherapy or radiotherapy were performed. Two died of local NHL at 5 and 6 months respectively after diagnosis. One patient is still alive at 8 months after the first treatment for NHL. Early diagnosis is essential to improve the prognosis of these NHLs although it is difficult because of the co-existent pyothorax. Following features seemed to be useful for diagnosis: 1) chest pain or shoulder pain, 2) elevation of LDH level, 3) mass shadow in computed tomography, and 4) abnormal uptake of gallium 67. As precise assessment of tumor size is difficult because of the co-existent pyothorax and necrosis, follow-up studies by gallium scan or magnetic resonance imaging might be useful for proper treatment.