The radiomics approach of sialadenitis using various imaging modality in animal model

Abstract

Purpose: This study was to establish reliable radiomics featureincomputed tomography (CT), magnetic resonance imaging (MRI) and ultrasonography (US) for diagnosis of sialadenitis induced in rat model. Materials and Methods:Seven-week, 350-400g weightedwister strain rats were divided into experimental (n=7) and control (n=8) groups. For all subjects, contrast enhanced-computed tomography (CECT), T2-weighted MRI, and US were obtained.After the imaging examination, control subjects were sacrificed and submandibular glands were extirpated. For the experimental subjects, left submandibular glands were exposed to induced transient sialadenitis, and the right gland was ligated to inducechronic sialadenitis. After 2 weeks from the surgery, the same imaging examinations, CECT, MRI, and US, were performed. Then the experimental subjects were also sacrifices to extract the gland. Observation of all images was conducted through visual diagnosis and histological diagnosis of extracted glands, and through this, it was identified in three categories (normal, transient, chronic sialadenitis). For radiomics analysis, region of interest (ROI) was determined following the border of submandibular gland in CECT, MRI and US. The values of 50 ramdiomics features were obtained using LIFEx software. Then the features consistent with visual diagnosis were selected. All radiomics values according to the gland state were compared using Kruskcal willis test with 95% confidential interval. Post-hoc analysis was performed using Bonferroni test. Results:There were 13 radiomics features showing statistical difference among gland status in CECT. All 13 features showed statistical significant differences between normal and chronic sialadenitis(P<0.05). For MRI, 9 features were selected, and they showed statistical significant difference between normal and chronic sialadenitis gland.Three radiomics features were selected in US,showingdifferences between normal and chronic sialadenitis while one of which also showed differences between transient and chronic sialadenitis. Conclusions: All imaging modality, CECT, MRI and US showed radiomics features consistent with visual diagnosis.This suggests that radiomics characteristics can be useful for recognizing the progression stage of sialadenitis based on the objective values.

연구목적: 본연구는타액선의염증을유발한랫트의전산화단층영상, 자기공명영상및초음파영상에서라디오믹스분석을시행하여타액선염을진단하기위해적합한특성값을파악하고자시행되었다. 특히, 초음파영상에서신뢰할수있으며재현성있는변수를확립하고자한다. 연구대상및방법: 일정기간동일조건하에사육된 7주, 350~400g 크기의 wistar strain 랫트를 1주일의순응기간을거친뒤실험군7마리및대조군8마리로분류하였다. 모든랫트에서악하선부위의조영증강전산화단층영상, T2 강조자기공명영상및초음파영상을획득하였으며, 이중대조군은희생하여타액선을적출하였다. 실험군은목부위를절개하여양측악하선을모두노출하였으며, 우측악하선의분비관은결찰시행하여,좌측타액선은일시적염증,우측은만성염증을유발하였다. 2주뒤조영증강전산화단층영상, T2 강조자기공명영상및초음파영상을획득하였으며희생하여악하선을적출하였다. 획득된모든영상에서1명의영상치의학자와1명의구강악안면외과의가합의하에타액선실질조직의패턴을육안으로평가시행하였다.술전타액선이모두정상패턴을보이는지,술후타액선이일시적혹은만성적타액선염상태를보이는지여부에대해평가하였다.세가지상태의타액선에대해조직학적으로정상,일시적및만성타액선염을확인하였다. 전산화단층영상, T2 강조자기공명영상및초음파영상모두에서라디오믹스분석을위해LIFEx 소프트웨어에서타액선의경계를따라관심영역을설정하였으며,총 50개의라디오믹스특성에대한값을획득하였다. 육안으로평가된결과와일치하는라디오믹스특성을추출하였다. 연구결과:타액선상태에따라통계학적으로유의한차이를보이는라디오믹스특성은전산화단층영상에서 13개, 자기공명영상에서 9개, 초음파에서 3개로나타났다. 전산화단층영상의13개특성값은모두정상과만성적타액선염사이에유의한차이를보였다. 12개특성에서는정상과일시적타액선염간에도통계적으로유의한값의차이를보였다.자기공명영상의경우에도 9개특성모두정상과만성적타액선염간차이를보였으며,이중4개의특성에서는일시적타액선염과만성적타액선염사이에도값의유의한차이가있었다.초음파영상에서선별된변수들역시정상과만성적타액선염간차이가있었으며,이중 1개의특성에서는일시적및만성적타액선염간에도차이를보였다. 연구결론:각각의영상에서모두 CT 값및 T2 신호강도분석과유사한경향성을보이는라디오믹스특성값을찾을수있었다. 특히, 전산화단층영상의경우정상과일시적타액선염사이에유의한차이를보이는특성값이다수존재하였는데, 이는초기염증진단에서전산화단층영상이유리할수있음을보여준다. 또한, 자기공명영상및초음파영상의경우일시적타액선염과만성적타액선염사이에유의한차이를보이는특성이있었다. 이는염증의진행상황과단계별구분에유용할수있음을시사한다.본연구를통해초음파영상의라디오믹스특성분석을통한타액선염의진단및추적검사에적용가능성을알수있다.