Enfermedades pulmonares intersticiales difusas asociadas al tabaquismo / Diffuse interstitial lung diseases associated with smoking

El interrogatorio sobre hábito tabáquico no debe obviarse jamás, pues el abanico de posibilidades diagnósticas inherentes es amplio. Es un gesto clínico fundamental frente a individuos que consultan por síntomas y/o hallazgos radiológicos casuales. Presentamos tres casos clínicos: síndrome de combinación de fibrosis pulmonar y enfisema, neumonitis intersticial descamativa e histiocitosis de células de Langerhans, como parte del abanico de las enfermedades pulmonares intersticiales difusas asociadas a tabaco (EPIDAT), donde la tomografía de alta resolución de tórax tiene un rol destacado. Palabras clave: tabaquismo; enfisema; enfermedades pulmonares intersticiales; histiocitosis de células de Langerhans

Questioning about smoking habits should never be ignored, since the range of inherent diagnostic possibilities is wide. It is a fundamental clinical step facing individuals who consult for symptoms and/or casual radiological findings. We present three clinical cases: the combined syndrome of pulmonary fibrosis and emphysema, desquamative interstitial pneumonitis, and Langerhans cell histiocytosis, as part of the range of tobacco-associated diffuse interstitial lung diseases (EPIDAT), where high-resolution chest tomography has a prominent role. Key words: smoking; emphysema; interstitial lung diseases; Langerhans cell histiocytosis

Gastritis enfisematosa. Reporte de un caso en el adulto mayor / Emphysematous gastritis. Report of a case in the elderly

Introducción: la gastritis enfisematosa es una patología poco común pero con alta mortalidad, su presentación clínica es insidiosa, la imagen por tomografía se distingue por un patrón de burbujas lineales con engrosamiento de la pared gástrica. Caso clínico: paciente masculino de 78 años, previamente sano, funcional, que fue ingresado por fractura pertrocantérica de cadera izquierda, quien durante la hospitalización presenta delirium hiperactivo, distención abdominal con disminución de perístalsis además de hipotensión arterial, se realiza tomografía abdominal con evidencia de dilatación gástrica y múltiples burbujas de aire en pared. Es manejado con antibiótico de amplio espectro, fluidoterapia y nutrición parenteral, con respuesta favorable.Conclusiones: la edad avanzada no conlleva por sí misma un peor pronóstico de la enfermedad, la evidencia apoya que un diagnóstico precoz y la intervención terapéutica temprana, son las medidas que han demostrado ser efectivas para la disminución de la mortalidad en pacientes con gastritis enfisematosa

Introduction: Emphysematous gastritis is an uncommon pathology but with high mortality, its clinical presentation is insidious, the tomography image is distinguished by a pattern of linear bubbles with thickening of the gastric wall.Background: This is a 78-year-old male, previously healthy, functional, who was admitted for pertrochanteric fracture of the left hip, who during hospitalization presented hyperactive delirium, abdominal distention with decreased perstalsis in addition to arterial hypotension, an abdominal tomography with evidence of gastric dilation and multiple air bubbles in the wall. He is managed with a broad spectrum antibiotic, fluid therapy and parenteral nutrition, with a favorable response.Conclusions: Advanced age does not in itself lead to a worse disease prognosis, the evidence supports that early diagnosis and early therapeutic intervention are the easures that have proven to be more effective in reducing mortality in patients with emphysematous gastritis.

In Vitro Fatigue Test of Lung Volume Reduction Loop / 中国医疗器械杂志

Lung volume reduction loop uses bronchoscopic lung volume reduction(BLVR) technology to compress and collapse the necrotic emphysema tissue and exhaust the internal gas to achieve the purpose of lung volume reduction to treat emphysema. After the lung volume reduction loop is implanted into the human body, the compressed part of the lung tissue tends to expand with breathing, which makes the lung volume reduction loop expand into a linear trend periodically. Fatigue resistance is one of the most important performance indexes of the lung volume reduction loop. In the paper, Z-direction vibration fatigue machine was used to simulate the changes of human respiratory cycle movement to test the fatigue performance of lung volume reduction loop, which can provide some reference for the test method of in vitro fatigue performance of lung volume reduction related products in the future.

Diagnosis and treatment for emphysematous pyelonephritis: analysis of 14 cases from a single centre / 中华外科杂志

Objective: To examine the modalities of treatment and clinical outcomes of emphysematous pyelonephritis (EPN), in order to improve the survival rate of EPN patients. Methods: Totally 14 patients diagnosed as EPN between October 2011 and November 2020 at Department of Urology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine were included in this article. Data collection including patient demographics, clinical manifestations, management and clinical outcomes were conducted by retrospective charts review, after receiving the institutional review board's approval. There were 11 females and 3 males with a median age of 59 years (range: 52 to 73 years). The lesions were located on the left side in 10 patients and right side in 4 patients. All the 14 patients suffered from fever, and present with severe sepsis or septic shock. The median time from symptom onset to admission to hospital was 3 days(range: 2 to 5 days). All cases had diabetes mellitus. Escherichia coli was the most common organism been cultured (11 cases), while Klebsiella pneumonia was the second (3 cases). CT scan showed bubbly or located gas in the renal parenchyma in 5 cases and presence of steaky or mottled gas in the renal parenchyma in 9 cases. All patients had been admitted to ICU for anti-septic shock therapy. Three patients had undergone percutaneous catheter drainage along with broad-spectrum antibiotics therapy while 3 patients had immediate nephrectomy, the other 8 cases had a combination of an initial percutaneous catheter drainage and second stage nephrectomy. Results: In this case series, 3 patients were died from EPN while the other 11 were survived. The median ICU stay time was 6 days (range: 3 to 11 days). Of the 3 patients died from EPN, 2 had undergone percutaneous catheter drainage along and 1 had received immediate nephrectomy. Among the 11 patients who were survived, only 1 had received percutaneous catheter drainage while the other 10 received nephrectomy (8 patients had staged nephrectomy). Follow-up was performed 6 months after discharge. Of the 11 surviving patients, 2 were lost to follow-up, and the remaining 9 patients had an creatine level of (118.4±29.4) μmol/L (range: 89 to 176 μmol/L). Conclusions: For patients coupled with diabetes who were initially diagnosed as acute pyelonephritis, the possibility of EPN should be considered when the disease progressed rapidly especially septic shock occurred. On the basis of empirical broad-spectrum antibiotics therapy and standardized anti-septic shock treatment, a combination of an initial percutaneous catheter drainage and second stage nephrectomy could be efficacious.

An aqueous pomegranate peel extract (Punica granatum) protect against Elastase-induced pulmonary emphysema in Sprague Dawley rats model

We investigated the effect of Punica granatum peel aqueous extract (PGE), on pulmonary inflammation and alveolar degradation induced by intratracheal administration of Elastase in Sprague Dawley rats. Lung inflammation was induced in rats by intratracheal instillation of Elastase. On day 1 and 2, animals received an intraperitoneal injection of PGE (200 mg/mL), three hours later, they were intratracheally instilled with 25U/kg pancreatic porcine Elastase. Animals were sacrificed 7 days later. Bronchoalveolar lavage (BAL) were collected and cellularity, histology and mRNA expression of Monocyte chemotactic protein 1(MCP-1), Tumor Necrosis Factor-Alpha (TNF-α), Interleukin 6 (IL-6), and Matrix Metalloproteinase-2 (MMP-2) were studied. In addition, activity of TNF- α, IL-6 and MCP-1 on BAL were also analyzed by ELISA Kit. Elastase administration increased: BAL cellularity, neutrophils recruitment and BAL MCP1, IL-6 expressions. It also increased lung TNF-α, MCP-1, MMP-2 expressions, platelets recruitment, histological parameters at 7th day of elastase treatment. Intraperitoneal injection of 200 mg/kg of PGE reduced, significantly, BAL cellularity, and neutrophils recruitment. However, in animal treated with PGE, MCP-1, MMP-2 and IL-6 on day 7, were similar to the Sham group. Treatment with PGE (200 mg/ kg) also significantly reduced lung TNF-α, and MCP-1 expression. This study reveals that PGE Punica granatum protects against elastase lung inflammation and alveolar degradation induced in rats

Transmogrificación placentaria de pulmón. Presentación atípica del enfisema bulloso / Placental transmogrification of the lung. Atypical presentation of the bullous emphysema

Resumen La transmogrificación placentaria del pulmón es una lesión extremadamente infrecuente, asociada al enfisema bulloso gigante y considerada por algunos autores una variante histológica del enfisema bulloso gigante unilateral. Su etiología aún es desconocida y representa un desafío tanto para el diagnóstico clínico como anatomopatológico. Presentamos el caso de un paciente joven, que consulta con disnea de un año de evolución, y cuyo diagnóstico postoperatorio incluye esta rara entidad.

Abstract Placental transmogrification of the lung is an extremely rare lesion, associated with giant bullous emphysema and considered by some authors to be a histological variant of unilateral giant bullous emphysema. Its etiology is still unknown and represents a challenge for both clinical and pathological diagnosis. We present the case of a young patient, who consults with dyspnea of one year of evolution, and whose postoperative diagnosis includes this rare entity.

Lowest observed adverse effect level of pulmonary pathological alterations due to nitrous acid exposure in guinea pigs

BACKGROUND@#We previously demonstrated that continuous exposure to nitrous acid gas (HONO) for 4 weeks, at a concentration of 3.6 parts per million (ppm), induced pulmonary emphysema-like alterations in guinea pigs. In addition, we found that HONO affected asthma symptoms, based on the measurement of respiratory function in rats exposed to 5.8 ppm HONO. This study aimed to investigate the dose-response effects of HONO exposure on the histopathological alterations in the respiratory tract of guinea pigs to determine the lowest observed adverse effect level (LOAEL) of HONO.@*METHODS@#We continuously exposed male Hartley guinea pigs (n = 5) to four different concentrations of HONO (0.0, 0.1, 0.4, and 1.7 ppm) for 4 weeks (24 h/day). We performed histopathological analysis by observing lung tissue samples. We examined samples from three guinea pigs in each group under a light microscope and measured the alveolar mean linear intercept (Lm) and the thickness of the bronchial smooth muscle layer. We further examined samples from two guinea pigs in each group under a scanning electron microscope (SEM) and a transmission electron microscope (TEM).@*RESULTS@#We observed the following dose-dependent changes: pulmonary emphysema-like alterations in the centriacinar regions of alveolar ducts, significant increase in Lm in the 1.7 ppm HONO-exposure group, tendency for hyperplasia and pseudostratification of bronchial epithelial cells, and extension of the bronchial epithelial cells and smooth muscle cells in the alveolar duct regions.@*CONCLUSIONS@#These histopathological findings suggest that the LOAEL of HONO is < 0.1 ppm.

Bulla con nivel hidroaéreo en su interior, interpretación y enfoque terapéutico / Air-Fluid Level Within Bulla: Interpretation and Therapeutic Approach

Bulla se define como un área de enfisema bien delimitada mayor o igual a 1cm de diámetro y pared fina epitelizada de grosor generalmente menor a 1mm. Se presentan preferentemente sobre los vértices pulmonares y se corresponden con un alargamiento de los espacios centrolobulillares1. Tienden a aumentar de volumen y complicarse con neumotórax, hemorragia e infección2. Durante la infección adquieren líquido, presencia de nivel hidroaéreo y sus paredes se engrosan2. Es importante la diferenciación con la neumonía perienfisematosa, la cual cursa con la infección del parénquima circundante generando una afectación por contigüidad a la bulla, produciendo volcado de líquido inflamatorio a la misma, y comprometiendo sistémicamente al paciente

Fibrosis pulmonar asociada a enfisema: no siempre relacionada con tabaquismo / Pulmonary fibrosis associated with emphysema: not always smoking related

Las enfermedades del intersticio pulmonar (ILD's) comprenden más de 100 afecciones,­algunas de causas conocidas y otras no­, que comparten un cuadro clínico, radiográfico y funcional. Muchas de ellas afectan además la luz y la pared bronquiolar como sucede por ejemplo en la Neumonía Crónica Organizada (COP) y en la Bronquiolitis Respiratoria asociada a Intersticiopatía (BR-ILD)

Síndrome combinado de fibrosis pulmonar y enfisema en artritis reumatoide / Combined pulmonary fibrosis syndrome and emphysema in rheumatoid arthritis

Caso clínico: Paciente de sexo masculino, de 72 años. Ingresa por un cuadro de disnea súbita mMRC 2-3, con progresión a disnea mMRC 4. Refiere tos crónica sin cambio en sus características. Niega fiebre. Antecedentes: Ex tabaquista (36 paquetes/año), con antecedentes de artritis reumatoidea, y fibrosis pulmonar. Examen físico: Saturación de oxígeno 88% aire ambiente, taquipneico. Con hipoventilación y crepitantes velcro hasta el tercio medio, bilaterales. Exámenes complementarios: Hemograma normal. La gasometría arterial revela alcalosis respiratoria compensada. La espirometría y los volúmenes pulmonares se encuentran dentro de los límites de referencia, se observa disminución severa de la capacidad de difusión pulmonar (DLCO). La tomografía computarizada torácica de alta resolución (TCAR) (Figuras 1 y 2) muestra enfisema en los lóbulos superiores, con fibrosis de predominio en lóbulos inferiores, no se observan signos indirectos de hipertensión pulmonar

Interrelación entre enfisema y disfunción diastólica ventricular izquierda: nuestra experiencia en el Hospital Privado Centro Médico de Córdoba / Interrelation between emphysema and diastolic dysfunction left ventricular: our experience in the Hospital Private Medical Center of Córdoba

Introducción: Las consecuencias hemodinámicas de la hiperinflación y el enfisema se producen por compresión cardíaca debido a elevadas presiones intratorácicas, lo que produciría disfunción diastólica ventricular izquierda subclínica. Nuestro objetivo es correlacionar el porcentaje de enfisema con parámetros de función pulmonar y con el tamaño de las cámaras cardíacas, función sistólica ventricular global y función diastólica ventricular izquierda, en la enfermedad pulmonar obstructiva crónica. Materiales y Métodos: participaron pacientes con enfermedad pulmonar obstructiva crónica moderada y severa asistidos en un Servicio de Neumonología del Hospital Privado Centro Médico de Córdoba, desde el 01 de enero al 31 de octubre de 2014. Se cuantificó el volumen y porcentaje de enfisema por tomografía computada de alta resolución, se realizaron espirometría, prueba de marcha de seis minutos, determinación de volúmenes pulmonares y ecocardiograma Doppler color. Resultados: Se encontró correlación negativa y significativa del porcentaje de enfisema con el porcentaje del valor teórico del VEF1 postbroncodilatador (p = 0.005) y el cociente VEF1/CVF postbroncodilatador (p = 0.004) y; además, entre el cociente VEF1/CVF postbroncodilatador y el volumen del enfisema en cm3 (p = 0.000). De un subgrupo de 20 pacientes. Siete pacientes (35%) presentaron diagnóstico de disfunción diastólica ventricular izquierda de grado I. Se encontraron correlaciones negativas pero no significativas entre el porcentaje de enfisema con función sistólica ventricular global y el tamaño de las cámaras cardíacas. Conclusiones: Se destaca la utilidad del ecocardiograma para reducir el sub diagnóstico de disfunción diastólica ventricular izquierda. Se destaca la importancia que tendrían la hiperinflación y el enfisema en el deterioro del patrón de llenado diastólico ventricular izquierdo y en la reducción del tamaño de las cámaras cardíacas con disminución en la tolerancia al ejercicio.

Interrelationship between Emphysema and Left Ventricular Diastolic Dysfunction: our experience in the Hospital Privado Centro Médico de Córdoba

Introduction: The hemodynamic consequences of hyperinflation and emphysema are produced by cardiac compression due to high intrathoracic pressures, which could produce subclinical left ventricular diastolic dysfunction. Our purpose is to correlate the percentage of emphysema with lung function parameters and cardiac chamber sizes, the global ventricular systolic function and the left ventricular diastolic function, in cases of chronic obstructive pulmonary disease. Materials and Methods: The participants were patients with moderate and severe chronic obstructive pulmonary disease treated in the Pulmonology Service of the Hospital Privado Centro Médico de Córdoba from January 1st to October 13th, 2014. We quantified the volume and percentage of emphysema by high resolution computed tomography and carried out a spirometry, a Six Minute Walk Test, measurement of pulmonary volumes and color Doppler echocardiography. Results: We found a significant negative correlation between the percentage of emphysema and the percentage of the post-bronchodilator FEV1 theoretical value (p = 0.005) and the post-bronchodilator FEV1/FVC (Forced Expiratory Volume in First Second/Forced Vital Capacity) quotient (p = 0.004), and, also, between the post-bronchodilator FEV1/FVC quotient and the emphysema volume in cm3 (p = 0.000). Out of a sub-group of 20 patients, seven patients (35%) were diagnosed with grade I left ventricular diastolic dysfunction. We found negative, but not significant correlations between the percentage of emphysema and global ventricular systolic function and cardiac chamber sizes. Conclusions: We should emphasize the usefulness of the echocardiography in reducing sub-diagnoses of left ventricular diastolic dysfunction. We should also stress on the importance hyperinflation and emphysema would have in the impairment of the left ventricular diastolic filling pattern and in the decrease in cardiac chamber sizes, with a decrease in exercise tolerance.

A Stepwise Diagnostic Approach to Cystic Lung Diseases for Radiologists

Lung cysts are commonly seen on computed tomography (CT), and cystic lung diseases show a wide disease spectrum. Thus, correct diagnosis of cystic lung diseases is a challenge for radiologists. As the first diagnostic step, cysts should be distinguished from cavities, bullae, pneumatocele, emphysema, honeycombing, and cystic bronchiectasis. Second, cysts can be categorized as single/localized versus multiple/diffuse. Solitary/localized cysts include incidental cysts and congenital cystic diseases. Multiple/diffuse cysts can be further categorized according to the presence or absence of associated radiologic findings. Multiple/diffuse cysts without associated findings include lymphangioleiomyomatosis and Birt-Hogg-Dubé syndrome. Multiple/diffuse cysts may be associated with ground-glass opacity or small nodules. Multiple/diffuse cysts with nodules include Langerhans cell histiocytosis, cystic metastasis, and amyloidosis. Multiple/diffuse cysts with ground-glass opacity include pneumocystis pneumonia, desquamative interstitial pneumonia, and lymphocytic interstitial pneumonia. This stepwise radiologic diagnostic approach can be helpful in reaching a correct diagnosis for various cystic lung diseases.

Clinical Utility of Quantitative CT Analysis for Fissure Completeness in Bronchoscopic Lung Volume Reduction: Comparison between CT and Chartis™

OBJECTIVE: The absence of collateral ventilation (CV) is crucial for effective bronchoscopic lung volume reduction (BLVR) with an endobronchial valve. Here, we assessed whether CT can predict the Chartis™ results. MATERIALS AND METHODS: This study included 69 patients (mean age: 70.9 ± 6.6 years; 66 [95.7%] males) who had undergone CT to assess BLVR eligibility. The Chartis™ system (Pulmonox Inc.) was used to check CV. Experienced thoracic radiologists independently determined the completeness of fissures on volumetric CT images. RESULTS: The comparison between the visual and quantitative analyses revealed that 5% defect criterion showed good agreement. The Chartis™ assessment was performed for 129 lobes; 11 (19.6%) of 56 lobes with complete fissures on CT showed positive CV, while this rate was significantly higher (40 of 49 lobes, i.e., 81.6%) for lobes with incomplete fissures. The size of the fissure defect did not affect the rate of CV. Of the patients who underwent BLVR, 22 of 24 patients (91.7%) with complete fissures and three of four patients with incomplete fissures (75%) achieved target lobe volume reduction (TLVR). CONCLUSION: The quantitative analysis of fissure shows that incomplete fissures increased the probability of CV on Chartis™, while the defect size did not affect the overall rates. TLVR could be achieved even in some patients with relatively large fissure defect, if they showed negative CV on Chartis™.

Non-Diagnostic CT-Guided Percutaneous Needle Biopsy of the Lung: Predictive Factors and Final Diagnoses

OBJECTIVE: To investigate the predictive factors for a non-diagnostic result and the final diagnosis of pulmonary lesions with an initial non-diagnostic result on CT-guided percutaneous transthoracic needle biopsy. MATERIALS AND METHODS: All percutaneous transthoracic needle biopsies performed over a 4-year period were retrospectively reviewed. The initial pathological results were classified into three categories—malignant, benign, and non-diagnostic. A non-diagnostic result was defined when no malignant cells were seen and a specific benign diagnosis could not be made. The demographic data of patients, lesions' characteristics, technique, complications, initial pathological results, and final diagnosis were reviewed. Statistical analysis was performed using binary logistic regression. RESULTS: Of 894 biopsies in 861 patients (male:female, 398:463; mean age 67, range 18–92 years), 690 (77.2%) were positive for malignancy, 55 (6.2%) were specific benign, and 149 (16.7%) were non-diagnostic. Of the 149 non-diagnostic biopsies, excluding 27 cases in which the final diagnosis could not be confirmed, 36% revealed malignant lesions and 64% revealed benign lesions. Predictive factors for a non-diagnostic biopsy included the size ≤ 15 mm, needle tract traversing emphysematous lung parenchyma, introducer needle outside the lesion, procedure time > 60 minutes, and presence of alveolar hemorrhage. Non-diagnostic biopsies with a history of malignancy or atypical cells on pathology were more likely to be malignant (p = 0.043 and p = 0.001). CONCLUSION: The predictive factors for a non-diagnostic biopsy were lesion size ≤ 15 mm, needle tract traversing emphysema, introducer needle outside the lesion, procedure time > 60 minutes, and presence of alveolar hemorrhage. Thirty-six percent of the non-diagnostic biopsies yielded a malignant diagnosis. In cases with a history of malignancy or the presence of atypical cells in the biopsy sample, a repeat biopsy or surgical intervention should be considered.

A Case of Subcutaneous Emphysema and Pneumomediastinum after Palatine Tonsillectomy / 대한이비인후과학회지

Palatine tonsillectomy is a very common procedure and it is relatively safe and has few complications. However, some severe, although rare, complications that can lead a patient to life-threatening status can occur following palatine tonsillectomy. Subcutaneous or mediastinal emphysema is one of the severe complications. We report a case of subcutaneous emphysema and pneumomediastinum after palatine tonsillectomy in a healthy 18-year-old man. After conservative management, subcutaneous emphysema was subsided without other complications.

Potential Therapeutic Strategy in Chronic Obstructive Pulmonary Disease Using Pioglitazone-Augmented Wharton's Jelly-Derived Mesenchymal Stem Cells / 결핵

BACKGROUND: A recent study reported that mesenchymal stem cells possess potential cellular therapeutic properties for treating patients with chronic obstructive pulmonary disease, which is characterized by emphysema. We examined the potential therapeutic effect of Wharton's Jelly-derived mesenchymal stem cells (WJMSCs), following pretreatment with pioglitazone, in lung regeneration mouse emphysema models. METHODS: We used two mouse emphysema models, an elastase-induced model and a cigarette smoke-induced model. We intravenously injected WJMSCs (1×104/mouse) to mice, pretreated or not, with pioglitazone for 7 days. We measured the emphysema severity by mean linear intercepts (MLI) analysis using lung histology. RESULTS: Pioglitazone pretreated WJMSCs (pioWJMSCs) were associated with greater lung regeneration than non-augmented WJMSCs in the two mouse emphysema models. In the elastase-induced emphysema model, the MLIs were 59.02±2.42 µm (n=6), 72.80±2.87 µm (n=6), for pioWJMSCs injected mice, and non-augmented WJMSCs injected mice, respectively (p<0.01). Both pioWJMSCs and non-augmented WJMSCs showed regenerative effects in the cigarette smoke emphysema model (MLIs were 41.25±0.98 [n=6] for WJMSCs and38.97±0.61 µm [n=6] for pioWJMSCs) compared to smoking control mice (51.65±1.36 µm, n=6). The mean improvement of MLI appeared numerically better in pioWJMSCs than in non-augmented WJMSCs injected mice, but the difference did not reach the level of statistical significance (p=0.071). CONCLUSION: PioWJMSCs may produce greater lung regeneration, compared to non-augmented WJMSCs, in a mouse emphysema model.

Prediction of Pulmonary Function in Patients with Chronic Obstructive Pulmonary Disease: Correlation with Quantitative CT Parameters

OBJECTIVE: We aimed to evaluate correlations between computed tomography (CT) parameters and pulmonary function test (PFT) parameters according to disease severity in patients with chronic obstructive pulmonary disease (COPD), and to determine whether CT parameters can be used to predict PFT indices. MATERIALS AND METHODS: A total of 370 patients with COPD were grouped based on disease severity according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) I–IV criteria. Emphysema index (EI), air-trapping index, and airway parameters such as the square root of wall area of a hypothetical airway with an internal perimeter of 10 mm (Pi10) were measured using automatic segmentation software. Clinical characteristics including PFT results and quantitative CT parameters according to GOLD criteria were compared using ANOVA. The correlations between CT parameters and PFT indices, including the ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) and FEV1, were assessed. To evaluate whether CT parameters can be used to predict PFT indices, multiple linear regression analyses were performed for all patients, Group 1 (GOLD I and II), and Group 2 (GOLD III and IV). RESULTS: Pulmonary function deteriorated with increase in disease severity according to the GOLD criteria (p < 0.001). Parenchymal attenuation parameters were significantly worse in patients with higher GOLD stages (p < 0.001), and Pi10 was highest for patients with GOLD III (4.41 ± 0.94 mm). Airway parameters were nonlinearly correlated with PFT results, and Pi10 demonstrated mild correlation with FEV1/FVC in patients with GOLD II and III (r = 0.16, p = 0.06 and r = 0.21, p = 0.04, respectively). Parenchymal attenuation parameters, airway parameters, EI, and Pi10 were identified as predictors of FEV1/FVC for the entire study sample and for Group 1 (R2 = 0.38 and 0.22, respectively; p < 0.001). However, only parenchymal attenuation parameter, EI, was identified as a predictor of FEV1/FVC for Group 2 (R2 = 0.37, p < 0.001). Similar results were obtained for FEV1. CONCLUSION: Airway and parenchymal attenuation parameters are independent predictors of pulmonary function in patients with mild COPD, whereas parenchymal attenuation parameters are dominant independent predictors of pulmonary function in patients with severe COPD.

CT Image Conversion among Different Reconstruction Kernels without a Sinogram by Using a Convolutional Neural Network

OBJECTIVE: The aim of our study was to develop and validate a convolutional neural network (CNN) architecture to convert CT images reconstructed with one kernel to images with different reconstruction kernels without using a sinogram. MATERIALS AND METHODS: This retrospective study was approved by the Institutional Review Board. Ten chest CT scans were performed and reconstructed with the B10f, B30f, B50f, and B70f kernels. The dataset was divided into six, two, and two examinations for training, validation, and testing, respectively. We constructed a CNN architecture consisting of six convolutional layers, each with a 3 × 3 kernel with 64 filter banks. Quantitative performance was evaluated using root mean square error (RMSE) values. To validate clinical use, image conversion was conducted on 30 additional chest CT scans reconstructed with the B30f and B50f kernels. The influence of image conversion on emphysema quantification was assessed with Bland–Altman plots. RESULTS: Our scheme rapidly generated conversion results at the rate of 0.065 s/slice. Substantial reduction in RMSE was observed in the converted images in comparison with the original images with different kernels (mean reduction, 65.7%; range, 29.5–82.2%). The mean emphysema indices for B30f, B50f, converted B30f, and converted B50f were 5.4 ± 7.2%, 15.3 ± 7.2%, 5.9 ± 7.3%, and 16.8 ± 7.5%, respectively. The 95% limits of agreement between B30f and other kernels (B50f and converted B30f) ranged from −14.1% to −2.6% (mean, −8.3%) and −2.3% to 0.7% (mean, −0.8%), respectively. CONCLUSION: CNN-based CT kernel conversion shows adequate performance with high accuracy and speed, indicating its potential clinical use.