Automated segmentation of dental CBCT image with prior‐guided sequential random forests

• Published in: Medical physics (Lancaster) Vol. 43; no. 1; pp. 336 - 346
• Main Authors: Wang, Li, Gao, Yaozong, Shi, Feng, Li, Gang, Chen, Ken‐Chung, Tang, Zhen, Xia, James J., Shen, Dinggang
• Format: Journal Article
• Language: English
• Published: United States American Association of Physicists in Medicine 01.01.2016
• Subjects: Adolescent; Adult; Algorithms; atlas based segmentation; Automation; Biological material, e.g. blood, urine; Haemocytometers; BIOMEDICAL RADIOGRAPHY; CBCT; Child; Computed tomography; Computerised tomographs; computerised tomography; COMPUTERIZED TOMOGRAPHY; Cone beam computed tomography; craniomaxillofacial deformities; Decision trees; dentistry; Dentistry; Apparatus or methods for oral or dental hygiene; DIAGNOSIS; DIAGNOSTIC IMAGING (IONIZING AND NON-IONIZING); Digital computing or data processing equipment or methods, specially adapted for specific applications; Female; GROUND TRUTH MEASUREMENTS; Humans; image classification; Image data processing or generation, in general; Image Processing, Computer-Assisted - methods; image segmentation; In which a programme is changed according to experience gained by the computer itself during a complete run; Learning machines; Inference methods or devices; ITERATIVE METHODS; JAW; learning (artificial intelligence); Male; Mandible - diagnostic imaging; Maxilla - diagnostic imaging; maximal intercuspation; Medical image artifacts; Medical image noise; medical image processing; Medical image segmentation; Medical treatment planning; Middle Aged; NOISE; PATIENTS; PLANNING; prior knowledge; Probability; RADIATION PROTECTION AND DOSIMETRY; RADIOLOGY AND NUCLEAR MEDICINE; random forest; Segmentation; Sequence analysis; Three dimensional image processing; Young Adult
• DOI: 10.1118/1.4938267
• ISSN: 0094-2405; 2473-4209

Purpose: Cone‐beam computed tomography (CBCT) is an increasingly utilized imaging modality for the diagnosis and treatment planning of the patients with craniomaxillofacial (CMF) deformities. Accurate segmentation of CBCT image is an essential step to generate 3D models for the diagnosis and treatment planning of the patients with CMF deformities. However, due to the image artifacts caused by beam hardening, imaging noise, inhomogeneity, truncation, and maximal intercuspation, it is difficult to segment the CBCT. Methods: In this paper, the authors present a new automatic segmentation method to address these problems. Specifically, the authors first employ a majority voting method to estimate the initial segmentation probability maps of both mandible and maxilla based on multiple aligned expert‐segmented CBCT images. These probability maps provide an important prior guidance for CBCT segmentation. The authors then extract both the appearance features from CBCTs and the context features from the initial probability maps to train the first‐layer of random forest classifier that can select discriminative features for segmentation. Based on the first‐layer of trained classifier, the probability maps are updated, which will be employed to further train the next layer of random forest classifier. By iteratively training the subsequent random forest classifier using both the original CBCT features and the updated segmentation probability maps, a sequence of classifiers can be derived for accurate segmentation of CBCT images. Results: Segmentation results on CBCTs of 30 subjects were both quantitatively and qualitatively validated based on manually labeled ground truth. The average Dice ratios of mandible and maxilla by the authors' method were 0.94 and 0.91, respectively, which are significantly better than the state‐of‐the‐art method based on sparse representation (p‐value < 0.001). Conclusions: The authors have developed and validated a novel fully automated method for CBCT segmentation.