Radiologic characterization of emphysema's pattern of distribution - a subjective approach

Radiologic characterization of emphysema's pattern of distribution - a subjective approach Poster No.: C-0866 Congress: ECR 2014 Type: Educational Exhibit Authors: J. Praia, C. Maciel, J. Pereira, J. Albuquerque, H. N. E. 1 2 1 2 2 1 2 Bastos ; Barreiro/PT, Porto/PT Keywords: Chronic obstructive airways disease, Technical aspects, Staging, CT-High Resolution, CT, Thorax, Respiratory system, Lung DOI: 10.1594/ecr2014/C-0866 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 25

Learning objectives Brief overview of the epidemiological, clinical and imagiologic characteristics of emphysema. Description and illustration of a subjective grading system for the distribution's pattern of emphysema and of its radiologic and clinical practical utility. Background Pulmonary emphysema is an abnormal permanent enlargement of the airspaces distal to the terminal bronchioles, accompanied by destruction of the alveolar wall and without obvious fibrosis. Pulmonary emphysema is part of the chronic obstructive pulmonary disease (COPD) spectrum and encompasses a number of entities and morphological patterns, of which the most important subtypes are centrilobular (most common), panlobular and paraseptal. Epidemiologically speaking, approximately 210 million people are affected worldwide, leading to 3 million annual deaths, total. It is predominantly a disease of middle to late life owing to the cumulative effect of smoking and other environmental risk factors. The incidence is now equal between both genders. Patients with genetic risk factors such as alpha-1-antitrypsin deficiency (AAT) may present earlier, according to phenotype. Risk factors include smoking (most common by far), asthma (the combination with smoking greatly increases the risk), AAT deficiency and intravenous injection of methylphenidate (the so-called Ritalin lung). Emphysema can be graded quantitatively and qualitatively. The former, called the emphysema index, is assessed using specific computer software, which automatically detects lung contours and plots histograms to determine the lung attenuation values, allowing the calculation of the relative percentage of pulmonary area occupied by pixels with attenuation values lower than 950 Hounsfield Units (HU). The latter regards the pattern of emphysema's distribution in the lung and can be graded by objective, semi-objective and subjective (visual scoring) methods. Page 2 of 25

This poster focus on a subjective method, easily applicable on any Radiology Department with access to a CT scan. Findings and procedure details Advances in CT scanning and specifically designed software now allow precise assessment of the extent of emphysema - emphysema index. Areas of the lung with a density below a given threshold (commonly -950 HU) are designated as emphysematous. In addition, the technology can be used to assess the distribution of emphysematous disease, an approach that has been utilised in assessing patients for (and in the outcomes of) lung volume reduction surgery and also in monitoring changes in emphysema longitudinally in AAT-deficient patients. There are physiologic differences between the lung regions, and these systems enable the assessment of the influence of regional heterogeneity on pulmonary function in emphysema-stricken patients. The distribution of the parenchymal damage varies between individuals, but the reasons for this are not known. This heterogeneity is reflected in the wide variation in clinical features seen. Computerized, quantitative assessment using the emphysema index slope is comparable to visual assessment in the evaluation of the pattern of distribution of emphysema. The visual scoring method assesses volumetric CT images on the coronal, sagittal, and axial planes to determine the heterogeneity of the upper/lower, anterior/posterior, and central/peripheral directions, respectively. It is a 5- point scoring system: Score 1 - indicates obviously predominant emphysema in upper, anterior, or central lung; Page 3 of 25

Fig. 1: Score 1 - obviously predominant emphysema in the central lung (axial plane, high-resolution CT scan). References: Department of Imagiology, Hospital de São João, EPE - Porto/ PT Page 4 of 25

Fig. 2: Score 1 - obviously predominant emphysema in the upper lung (coronal plane). References: Department of Imagiology, Hospital de São João, EPE - Porto/ PT Score 2 - somewhat predominant emphysema in upper, anterior, or central lung; Page 5 of 25

Fig. 3: Score 2 - somewhat predominant emphysema in central lung (axial plane). References: Department of Imagiology, Hospital de São João, EPE - Porto/PT Page 6 of 25

Fig. 4: Score 2 - somewhat predominant emphysema in upper lung (coronal plane). References: Department of Imagiology, Hospital de São João, EPE - Porto/PT Score 3 - equal extent of emphysema throughout the lungs; Page 7 of 25

Fig. 5: Score 3 - equal extent of emphysema throughout the lungs (axial plane). References: Department of Imagiology, Hospital de São João, EPE - Porto/PT Page 8 of 25

Fig. 6: Score 3 - equal extent of emphysema throughout the lungs (coronal plane). References: Department of Imagiology, Hospital de São João, EPE - Porto/PT Score 4 - somewhat predominant emphysema in lower, posterior, or peripheral lung; Page 9 of 25

Fig. 7: Score 4 - somewhat predominant emphysema in peripheral lung (axial plane). References: Department of Imagiology, Hospital de São João, EPE - Porto/PT Page 10 of 25

Fig. 8: Score 4 - somewhat predominant emphysema in inferior lung (coronal plane). References: Department of Imagiology, Hospital de São João, EPE - Porto/PT Score 5 - obviously predominant emphysema in lower, posterior, or peripheral lung. Page 11 of 25

Fig. 9: Score 5 - obviously predominant emphysema in peripheral lung (axial plane). The patient had alpha-1-antitrypsin deficiency and was also a smoker. References: Department of Imagiology, Hospital de São João, EPE - Porto/ PT Page 12 of 25

Fig. 10: Score 5 - obviously predominant emphysema in peripheral lung (axial plane, high-resolution CT scan). The patient had alpha-1-antitrypsin deficiency and was also a smoker. References: Department of Imagiology, Hospital de São João, EPE - Porto/ PT Regarding the pratical clinical utility of this scoring system, it has been shown that airflow limitation correlates with posterior and lower zone predominance (scores 4 and 5) whereas diffusion capacity better correlates with upper zone predominance (scores 1 and 2). Emphysema in the central zone (scores 1 and 2) has been shown to be more related to pulmonary function, compared with that in the peripheral zone (scores 4 and 5). Page 13 of 25

For example, lung volume reduction surgery is one of the therapeutic options for patients with severe emphysema. Because the degree of functional improvement varies widely among patients, it is essential to identify factors predicting outcome and set selection criteria for surgical candidates. Radiologic emphysema morphologic results, especially heterogeneity and upper lung predominance, are known as predictors of surgical outcome. Images for this section: Fig. 1: Score 1 - obviously predominant emphysema in the central lung (axial plane, highresolution CT scan). Page 14 of 25

Fig. 2: Score 1 - obviously predominant emphysema in the upper lung (coronal plane). Page 15 of 25

Fig. 3: Score 2 - somewhat predominant emphysema in central lung (axial plane). Page 16 of 25

Fig. 4: Score 2 - somewhat predominant emphysema in upper lung (coronal plane). Page 17 of 25

Fig. 5: Score 3 - equal extent of emphysema throughout the lungs (axial plane). Page 18 of 25

Fig. 6: Score 3 - equal extent of emphysema throughout the lungs (coronal plane). Page 19 of 25

Fig. 7: Score 4 - somewhat predominant emphysema in peripheral lung (axial plane). Page 20 of 25

Fig. 8: Score 4 - somewhat predominant emphysema in inferior lung (coronal plane). Page 21 of 25

Fig. 9: Score 5 - obviously predominant emphysema in peripheral lung (axial plane). The patient had alpha-1-antitrypsin deficiency and was also a smoker. Page 22 of 25

Fig. 10: Score 5 - obviously predominant emphysema in peripheral lung (axial plane, high-resolution CT scan). The patient had alpha-1-antitrypsin deficiency and was also a smoker. Page 23 of 25

Conclusion In addition to the emphysema index, regional heterogeneity of emphysema contributes to impairment of pulmonary function. Combined emphysema index and heterogeneity index better represent the airflow limitation component among patients' impaired function. Assessing the regional heterogeneity of emphysema using a visual scoring system is a very useful tool, with comparable results to an objective computerized system, allowing an accurate assessment of the impairment of pulmonary function on patients with this diagnosis. Personal information References Goddard PR, Nicholson EM, Laszlo G, Watt I. Computed tomography in pulmonary emphysema. Clin Radiol 1982; 33:379-387. Bergin C, Mu#ller NL, Nichols DM, et al. The diagnosis of emphysema: a computed tomographic-pathologic correlation. Am Rev Respir Dis. 1986; 133:541-546. Bankier AA, Maertelaer VD, Keyzer C, Gevenois PA. Pulmonary Emphysema: Subjective Visual Grading versus Objective Quantification with Macroscopic Morphometry and Thin-Section CT Densitometry. Radiology 1999; 211:851-858. Sciurba FC, Ernst A, Herth FJ, et al. A Randomized Study of Endobronchial Valves for Advanced Emphysema. N Engl J Med 2010;363:1233-44. de Torres JP, Bastarrika G, Zagaceta J, et al. Emphysema Presence, Severity, an Distribution Has Little Impact on the Clinical Presentation of a Cohort of Patients With Mild to Moderate COPD. CHEST 2011; 139(1):36-42. Chae EJ, Seo JB, Song JW, et al. Slope of Emphysema Index: An Objective Descriptor of Regional Heterogeneity of Emphysema and an Independent Determinant of Pulmonary Function. AJR 2010; 194:W248-W255. Page 24 of 25

Chhabra L, Sareen P, Gandagule A, Spodick D. Visual computed tomographic scoring of emphysema and its correlation with its diagnostic electrocardiographic sign: the frontal P vector. Journal of Electrocardiology (2012). Koyama H, Ohno Y, Yama Y, et al. Quantitative and Qualitative Assessments of Lung Destruction and Pulmonary Functional Loss from Reduced-Dose Thin-Section CT in Pulmonary Emphysema Patients. Acad Radiol 2010; 17:163-168. Cederlund K, Tyle n U, Jorfeldt L, Aspelin P. Classification of Emphysema in Candidates for Lung Volume Reduction Surgery: A New Objective and Surgically Oriented Model for Describing CT Severity and Heterogeneity. CHEST 2002; 122:590-596. Prokop M, Galanski M et al. Spiral and Multislice Computed Tomography of the Body, 1e, 2003, Thieme. Page 25 of 25