A texture analysis approach to quantify ventilation changes in hyperpolarised ³He MRI of the rat lung in an asthma model

Abstract

In preclinical research, allergic asthma is investigated in rats sensitised with the antigen ovalbumin (OVA), followed by a challenge with aerosolised OVA to induce an inflammatory reaction of the lower airways. This causes diffuse, nonfocal ventilation defects that lead to heterogeneously distributed signal intensities in hyperpolarised (HP) (3)He MR images, which are difficult to assess directly by diagnostic grading or volumetry. Texture analysis can characterise these changes and does not require segmentation of the lung structures prior to the analysis. The aim of this work was to evaluate a texture analysis approach to quantify changes in lung ventilation in HP (3)He MRI of OVA-challenged rats. OVA-challenged animals were treated with two different compound doses to evaluate the sensitivity of the texture analysis. Four groups were investigated using HP (3)He MRI at 4.7 T: controls, vehicle-treated, and low- and high-dose budesonide-treated rats. In addition, broncho-alveolar lavage was performed and the eosinophil cell count was used as a biological reference marker. First-order texture, geometrical features and features based on second-order statistics using run-length and grey-level co-occurrence matrices were calculated. In addition, wavelet transforms were applied to compute first-order statistics on multiple scales. The texture analysis was able to show significant differences between the control and untreated vehicle groups as well as between the vehicle and treatment groups. This is in agreement with the findings of the eosinophil cell counts, which were used as a marker for the severity of inflammation. However, not all features used in the different texture analysis methods could differentiate between the treatment groups. In conclusion, texture analysis can be used to quantify changes in lung ventilation as measured with HP (3)He MRI after therapeutic intervention with budesonide.

Effects of corticosteroid treatment on airway inflammation, mechanics, and hyperpolarized 3He magnetic resonance imaging in an allergic mouse model

“…In fact, such baseline defects were also described by Risse et al (15), who described the treatment effect of steroids on Ova/Ova treated rats using 3 He MRI. Although our sample size was small, it is somewhat striking to see the prevalence of these baseline defects in the left lung.…”

Using Texture Analysis to Determine Human Papillomavirus Status of Oropharyngeal Squamous Cell Carcinomas on CT

“…We chose to start with primary oropharyngeal SCC because HPV-positivity is a known prognostic factor for oropharyngeal SCC. 7,8,14 Despite our small sample size, many patients had to be eliminated from the study before we performed the texture analysis, predominately due to a combination of dental artifacts, patient motion, and small lesion size. The effects of the metallic streak artifacts and patient motion on the texture analysis are not fully known or described; therefore, for this initial pilot study, we tried to collect subjects with SCCs without metallic streak artifacts, to limit this as a potential confounder.…”

“…Texture analysis has been previously applied to evaluate subtle pathologic changes in an image that are not easily quantifiable by the human eye in other areas of the body, such as the liver, brain, and cartilage. [12][13][14][15][16][17] The purpose of this study was to use texture analysis to examine differences in texture features of HPV-positive and HPV-negative oropharyngeal SCC and to see whether there are significant differences in CT texture features related to HPV-positivity.…”

Quantitative variations in texture analysis features dependent on MRI scanning parameters: A phantom model

“…Numerous texture analysis features have been described in the literature and defined in the work of Haralick et al . The use of a texture analysis applied to imaging studies including CT and MRI have been previously performed for the evaluation of multiple nonneoplastic disorders including the evaluation for mesial temporal sclerosis on MRI, evaluation of intervertebral disc disease on MRI, evaluation of hepatic fibrosis on both CT and MRI, evaluation of subchondral bone on MRI . Prior oncologic studies have also employed texture analyses to evaluate specific tumor features including the assessment of HPV status of oropharyngeal squamous cell carcinomas, prognosis of head and neck neoplasms, classification of gastric and colorectal tumors on CT, genomic mapping and predictive marker identification of gliomas on MRI, the identification of potentially prognostic predictors in lung cancer, evaluation of genitourinary neoplasms on both CT and MRI, and for the radiomic classifications of breast carcinoma subtypes …”