Objective CT-Based Quantification of Lung Sequelae in Treated Patients With Paracoccidioidomycosis

Abstract

This study presents methodology for objectively quantifying the pulmonary region affected by emphysemic and fibrotic sequelae in treated patients with paracoccidioidomycosis. This methodology may also be applied to any other disease that results in these sequelae in the lungs.Pulmonary high-resolution computed tomography examinations of 30 treated paracoccidioidomycosis patients were used in the study. The distribution of voxel attenuation coefficients was analyzed to determine the percentage of lung volume that consisted of emphysemic, fibrotic, and normal tissue. Algorithm outputs were compared with subjective evaluations by radiologists using a scale that is currently used for clinical diagnosis.Affected regions in the patient images were determined by computational analysis and compared with estimates by radiologists, revealing mean (± standard deviation) differences in the scores for fibrotic and emphysemic regions of 0.1% ± 1.2% and −0.2% ± 1.0%, respectively.The computational results showed a strong correlation with the radiologist estimates, but the computation results were more reproducible, objective, and reliable.

Paracoccidioidomycosis: level of pulmonary sequelae in high resolution computed tomography images from patients of two endemic regions of Brazil

“…The algorithm implemented herein objectively quantifies fibrosis and emphysema using methodology described and validated in literature (17). The algorithm was developed in Matlab R2013a (Mathworks, Natick, MA, USA) and is based on histogram from lung tissues in HRCT exams.…”

“…The algorithm was developed in Matlab R2013a (Mathworks, Natick, MA, USA) and is based on histogram from lung tissues in HRCT exams. Validation of this method was made applying the algorithm in a virtual phantom with known amount of emphysema and fibrotic tissues (17).…”

“…The obtained data were age, sex, disease severity, symptom duration, clinical and apparent cure times, titers on double immunodiffusion (DID) test, and smoking history. These data were used for comparisons with quantifications of lung sequelae that were based on a computed algorithm (17).…”

“…pixels (i.e., the classified lung volumes). The total quantity of each tissue was calculated applying these steps in all slices of the HRCT exam (17).…”

“…Pulmonary alterations caused by PCM are evaluated preferable with high-resolution computed tomography (HRCT) since it is an image modality with additional information about the morphological characteristics and distribution of pulmonary lesions (17)(18)(19). Thus, it is extremely important to quantify the sequelae that are caused by PCM to better understand the mechanisms of the disease, to find possible variations between different forms of the disease and to allow the development of better therapies, according to the characteristics of the disease.…”