Pulmonary emphysema: subjective visual grading versus objective quantification with macroscopic morphometry and thin-section CT densitometry.

PURPOSE To compare subjective visual grading of pulmonary emphysema with macroscopic morphometry and computed tomographic (CT) densitometry. MATERIALS AND METHODS In 62 consecutive patients who underwent thinsection CT before surgical lung resection, emphysema was objectively quantified with computer-assisted macroscopic morphometry and CT densitometry. The percentage of lung macroscopically occupied by emphysema was compared with the percentage occupied on CT scans by pixels with attenuation values lower than a predefined threshold (CT densitometry). Three readers with varying degrees of expertise subjectively graded emphysema with visual assessment at two reading sessions. Data from objective quantification and subjective grading were analyzed with correlation coefficients, and interobserver and intraobserver agreement were calculated. RESULTS Subjective grading of emphysema showed less agreement with the macroscopic reference standard results (r = 0.439-0.505; P < .05) than with objective CT densitometric results (r = 0.555-0.623; P < .001). The 95% CIs for the intercepts of the linear regression lines were suggestive of systematic subjective overestimation of emphysema by all three readers. Interobserver agreement was moderate (kappa = 0.431-0.589). Intraobserver agreement was good to excellent (kappa = 0.738-0.936). The expertise of individual readers did not substantially influence results. CONCLUSION Systematic overestimation and moderate interobserver agreement may compromise subjective visual grading of emphysema, which suggests that subjective visual grading should be supplemented with objective methods to achieve precise, reader-independent quantification of emphysema.

[1]  Ranking the severity of emphysema on whole lung slices. Concordance of upper lobe, lower lobe, and entire lung ranks. , 1986, The American review of respiratory disease.

[2]  W. Kalender,et al.  Semiautomatic evaluation procedures for quantitative CT of the lung. , 1991, Journal of computer assisted tomography.

[3]  G. Ferraioli,et al.  Interobserver and interquipment variability of echo‐doppler examination of the portal vein: Effect of a cooperative training program , 1995, Hepatology.

[4]  H Nishitani,et al.  The diagnosis of mild emphysema. Correlation of computed tomography and pathology scores. , 1990, The American review of respiratory disease.

[5]  P. Gevenois,et al.  Whole Lung Sections for Computed Tomographic–Pathologic Correlations Modified Gough‐Wentworth Technique , 1993, Investigative radiology.

[6]  G. Snider,et al.  Emphysema: the first two centuries--and beyond. A historical overview, with suggestions for future research: Part 1. , 1992, The American review of respiratory disease.

[7]  J. Gough,et al.  The use of thin sections of entire organs in morbid anatomical studies. , 1949, Journal. Royal Microscopical Society.

[8]  W R Hendee,et al.  Detection of low-contrast signals. A comparison of observers with and without radiology training. , 1987, Investigative radiology.

[9]  N. Müller,et al.  Limited contribution of emphysema in advanced chronic obstructive pulmonary disease. , 1993, The American review of respiratory disease.

[10]  P De Vuyst,et al.  Comparison of computed density and macroscopic morphometry in pulmonary emphysema. , 1995, American journal of respiratory and critical care medicine.

[11]  N J Morrison,et al.  Limitations of computed tomography in the assessment of emphysema. , 1989, The American review of respiratory disease.

[12]  P. Paré,et al.  The diagnosis of emphysema. A computed tomographic-pathologic correlation. , 1986, The American review of respiratory disease.

[13]  M D Morgan,et al.  Detection and quantification of pulmonary emphysema by computed tomography: a window of opportunity. , 1992, Thorax.

[14]  D. Altman,et al.  STATISTICAL METHODS FOR ASSESSING AGREEMENT BETWEEN TWO METHODS OF CLINICAL MEASUREMENT , 1986, The Lancet.

[15]  C. Marquette,et al.  Inactivation of α1-Proteinase Inhibitor by Alveolar Inflammatory Cells from Smoking Patients with or without Emphysema , 1993 .

[16]  R H Hruban,et al.  High resolution computed tomography of inflation-fixed lungs. Pathologic-radiologic correlation of centrilobular emphysema. , 1987, The American review of respiratory disease.

[17]  W M Thurlbeck,et al.  A comparison of three methods of measuring emphysema. , 1970, Human pathology.

[18]  M S Frank,et al.  CT of the lung in patients with pulmonary emphysema: diagnosis, quantification, and correlation with pathologic and physiologic findings. , 1994, AJR. American journal of roentgenology.

[19]  P De Vuyst,et al.  Macroscopic assessment of pulmonary emphysema by image analysis. , 1995, Journal of clinical pathology.

[20]  K J Kearfott,et al.  Subjective Evaluations of Mammographic Accreditation Phantom Images by Three Observer Groups , 1994, Investigative radiology.

[21]  N. Müller,et al.  "Density mask". An objective method to quantitate emphysema using computed tomography. , 1988, Chest.

[22]  H E Rockette,et al.  Effect of observer instruction on ROC study of chest images. , 1990, Investigative radiology.

[23]  W M Thurlbeck,et al.  Emphysema: definition, imaging, and quantification. , 1994, AJR. American journal of roentgenology.

[24]  G. Laszlo,et al.  Computed tomography in pulmonary emphysema. , 1982, Clinical radiology.