This study aimed to explore topological prediction models for relapses, i.e., locoregional relapse (LRR) and distant metastasis (DM), of stage I patients with non-small cell lung cancer (NSCLC) prior to stereotactic ablative radiotherapy (SABR). Pretreatment planning computed tomography (CT) images of 125 primary NSCLC patients with SABR were divided into training (n = 65) and test datasets (n = 60). The signatures on lung tumor heterogeneity in CT images were constructed with conventional wavelet features (WFs), invariant topological features (original: TFs, inverted: iTFs), and their combined features (TWFs, iTWFs). Invariant topological features are related to intrinsic holes or heterogeneity in the tumors. The predictability of the tumor volumes which may be associated with lung cancer prognosis was also delved into with the image signatures. The patients were stratified into high-risk and low-risk groups using a radiomics score calculated from the signature. The predictability was evaluated using a p-value (log-rank test) between Kaplan–Meier (KM) curves of high-risk and low-risk groups, a concordance index (c-index), and a multiplication of negative logarithm of p-value and c-index (nLPC), which was considered a comprehensive evaluation index. For the test dataset, the iTFs and WFs combined with the tumor volumes had statistically significant differences of p-values (< 0.05) of the KM curves and higher nLPCs for the relapses. The signatures derived from inverted topology-based features and wavelet features combined with tumor volumes showed the potential of improving the high-risk and low-risk stratification for the relapses.
We aimed to develop a homology-based approach for prognostic prediction of lung cancer using novel topologically invariant radiomic features. The feasibility of homology-based radiomic features (HFs) was investigated by comparing them with conventional wavelet-based features (WFs) using a Kaplan–Meier analysis for a training dataset (n=135) and a validation dataset (n=70). A total of 13,825 HFs were obtained from histogram and texture features within gross tumor volumes on the computed tomography images using Betti numbers in homology. Similarly, 216 WFs were derived from four wavelet-decomposed images. The prognostic potentials of the HFs were evaluated using statistically significant differences (p-values < 0.05, log-rank test) to compare two survival curves of high- and low-risk patients, which were stratified with medians of radiomic scores of signatures constructed by using an elastic-net-regularized Cox proportional hazard model derived from a Cox-net algorithm. For the training dataset, p-values with hazard ratios (HRs) between the two survival curves were 6.7 × 10-6 for the HF (HR: 0.41, 95% confidence interval (CI): 0.26-0.65) and 5.9 × 10-3 for the WF (HR: 0.57, 95%CI: 0.37-0.88). For the validation dataset, p-values with HRs were 3.4 × 10-5 for the HF (HR: 0.32, 95%CI: 0.16-0.62) and 6.7 × 10-1 for the WF (HR: 0.88, 95%CI: 0.48-1.6). The HFs showed the more promising potential than the conventional features for prognostic prediction in lung cancer patients.
We have developed a magnetic resonance (MR) image-based radiomic biopsy approach for estimation of malignancy grade in parotid gland cancer (PGC). Preoperative T1- and T2-weighted MR images of 39 PGC patients with 20 highand 19 intermediate-/low-malignancy grades were employed. High- versus intermediate-/low-malignancy grades were estimated using MR-radiomic biopsy approaches, i.e. 972 hand-crafted feature and transfer learning of five pre-trained deep learning (DL) architectures (AlexNet, GoogLeNet, VGG-16, ResNet-101, DenseNet-201). The 39 patients were divided into 70% for training datasets and 30% for test datasets. The hand-crafted features were extracted from cancer regions in T1- and T2-weighted MR images. Three features were selected as a radiomic signature by using a least absolute shrinkage and selection operator (LASSO), whose coefficients of three features were used for constructing the radiomic score (Rad-score). The two grade malignancy was estimated by using an optimal cut-off value of Rad-score. On the other hand, last three layers of the DL architectures were replaced with new three layers for the estimation task. The DL architectures were fine-tuned with training datasets and were evaluated with test datasets. The performances of the MR-radiomic biopsy approaches were assessed by using the accuracy and the area under the receiver operating characteristic curve (AUC). The VGG-16 demonstrated the best performance (accuracy=85.4%, AUC=0.906), but the other approaches showed worse performances (Rad-score: 83.3%, 0.830, AlexNet: 84.4%, 0.915, GoogLeNet: 84.9%, 0.884, ResNet-101: 84.9%, 0.918, DenseNet-201: 84.4%, 0.869) than the VGG-16. The VGG-16-based MR-radiomic biopsy could be feasible for the malignancy grade estimation of PGC.
Histological subtypes, i.e. adenocarcinoma (ADN) and squamous cell carcinoma (SCC), identified from a single biopsy occasionally differ from those from actual surgical resections in NSCLC. For increasing the classification accuracy, we aim to develop an automated approach for classifying histological subtypes of NSCLC using Gaussian, linear and polynomial support vector machines (SVMs) with radiomic features. Classification models of Gaussian, linear and polynomial SVMs constructed with radiomic features achieved the areas under the curves of 0.7542, 0.7522 and 0.7531, respectively. Histological subtypes of NSCLC could be classified into ADN and SCC using a Gaussian SVM with radiomic features.
We have investigated an approach for prediction of parotid gland tumor (PGT) malignancy on preoperative magnetic resonance (MR) images. The PGT regions were segmented on the MR images of 42 patients. A total of 972 radiomic features were extracted from tumor regions in T1- and T2-weighted MR images. Five features were selected as a radiomic biomarker from the 972 features by using a least absolute shrinkage and selection operator (LASSO). Malignancies of PGTs (high grade versus intermediate and low grades) were predicted by using random forest (RF) and k-nearest neighbors (k-NN) with the radiomic biomarker. The proposed approach was evaluated using the accuracy and the mean area under the receiver operating characteristic curve (AUC) based on a leave-one-out cross validation test. The accuracy and AUC of the malignancy prediction of PGTs were 73.8% and 0.88 for the RF and 88.1% and 0.95 for the k-NN, respectively. Our results suggested that the radiomics-based k-NN approach using preoperative MR images could be feasible to predict the malignancy of PGT.
Our aim was to develop a Bayesian delineation framework of clinical target volumes (CTVs) for prostate cancer radiotherapy using an anatomical-features-based machine learning (AF-ML) technique. Probabilistic atlases (PAs) of the pelvic bone and the CTV were generated from 43 training cases. Translation vectors, which could move the CTV PAs to CTV locations, were estimated using the AF-ML after a bone-based registration between the PAs and planning computed tomography (CT) images. An input vector derived from 11 AF points was fed to three AF-ML techniques (artificial neural network: ANN, random forest: RF, support vector machine: SVM). The AF points were selected from edge points and centroids of anatomical structures around prostate. Reference translation vectors between centroids of CTV PAs and CTVs were given to the AF-ML as teaching data. The CTV regions were extracted by thresholding posterior probabilities produced by using the Bayesian inference with the translated CTV PA and likelihoods of planning CT values. The framework was evaluated based on a leave-one-out test with CTV contours determined by radiation oncologists. Average location errors of CTV PAs along the anterior-posterior and superior-inferior directions without AF-ML were 5.7±4.6 mm and 5.5±4.3 mm, respectively, whereas the errors along the two directions with ANN, which showed the best performance, were 2.4±1.7 mm and 2.2±2.2 mm, respectively. The average Dice’s similarity coefficient between reference and estimated CTVs for 44 test cases were 0.81±0.062 with ANN. The framework using AF-ML could accurately estimate CTVs of prostate cancer radiotherapy.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.