Quantitative CT Analysis of Diffuse Lung Disease

Abstract

Quantitative analysis of thin-section CT of the chest has a growing role in the clinical evaluation and management of diffuse lung diseases. This heterogeneous group includes diseases with markedly different prognoses and treatment options. Quantitative tools can assist in both accurate diagnosis and longitudinal management by improving characterization and quantification of disease and increasing the reproducibility of disease severity assessment. Furthermore, a quantitative index of disease severity may serve as a useful tool or surrogate endpoint in evaluating treatment efficacy. The authors explore the role of quantitative imaging tools in the evaluation and management of diffuse lung diseases. Lung parenchymal features can be classified with threshold, histogram, morphologic, and texture-analysis-based methods. Quantitative CT analysis has been applied in obstructive, infiltrative, and restrictive pulmonary diseases including emphysema, cystic fibrosis, asthma, idiopathic pulmonary fibrosis, hypersensitivity pneumonitis, connective tissue-related interstitial lung disease, and combined pulmonary fibrosis and emphysema. Some challenges limiting the development and practical application of current quantitative analysis tools include the quality of training data, lack of standard criteria to validate the accuracy of the results, and lack of real-world assessments of the impact on outcomes. Artifacts such as patient motion or metallic beam hardening, variation in inspiratory effort, differences in image acquisition and reconstruction techniques, or inaccurate preprocessing steps such as segmentation of anatomic structures may lead to inaccurate classification. Despite these challenges, as new techniques emerge, quantitative analysis is developing into a viable tool to supplement the traditional visual assessment of diffuse lung diseases and to provide decision support regarding diagnosis, prognosis, and longitudinal evaluation of disease. ©

Prognostic Implication of Volumetric Quantitative CT Analysis in Patients with COVID-19: A Multicenter Study in Daegu, Korea

“…In addition, the authors thought a relatively large number of mild pneumonia could affect the results; hence, we compared the mild and severe pneumonia groups. Again, our NALP (−950 to −701 HU) reflects that the lungs are almost completely ventilated as compared to severely COVID-affected lung regions, and it suggests how well respiratory functions could be maintained in advanced pneumonia, especially in ARDS ( 9 ). The well-aerated lung region in severe COVID-19 pneumonia is substantially reduced in volume and might represent an important parameter for patients treated with a mechanical ventilator in ICU or those expired.…”

“…Since the pathologic evaluation during the disease course of COVID-19 has not been established, computed tomography (CT) can reveal ground glass opacity and consolidation, which may reflect pathologic changes in these patients. Estimation of the volumetric quantification of chest CT images has been used in patients with various lung diseases including asthma, chronic obstructive pulmonary disease, interstitial lung disease, and oncological disease ( 9 10 11 ). Several studies have shown a potential role of chest CT volumetric quantification in predicting the mortality of ARDS ( 12 13 14 15 ).…”

Well-aerated Lung on Admitting Chest CT to Predict Adverse Outcome in COVID-19 Pneumonia

“…We used density threshold different than what suggested previously for ARDS, namely range form -900HU indicating nearly 90% gas and 10% tissue to -500HU indicating 50% gas and 50% tissue [28]. Again, our -950 to -700 HU range is intended for patients with respiratory I n P r e s s function at self-referral and indeed our definition reflects lung approximately completely ventilated as compared to severely compromised aerated lung in ARDS [14].…”

“…https://www.slicer.org) [13]. A fully automatic lung segmentation and analysis of lung parenchyma I n P r e s s segmentation (%S-WAL) was determined by density references from the literature, namely in the interval between -950 HU and -700 HU [14,15]. Furthermore, using the overall lung volume provided by software, the absolute volume of the well aerated lung (VOL-WAL) was calculated.…”

What’s New on Quantitative CT Analysis as a Tool to Predict Growth in Persistent Pulmonary Subsolid Nodules? A Literature Review

“…Among quantitative CT methods, those related to thoracic imaging are the most studied [20,22,23,[31][32][33][34][35][36][37][38][39][40][41][42][43]. In particular, the applications related to the classification and management of lung nodules are the most well-known and are used in both clinical practice and lung cancer screening programs [20,22,23,[31][32][33][34].…”