16 research outputs found
Grading Loss: A Fracture Grade-based Metric Loss for Vertebral Fracture Detection
Osteoporotic vertebral fractures have a severe impact on patients' overall
well-being but are severely under-diagnosed. These fractures present themselves
at various levels of severity measured using the Genant's grading scale.
Insufficient annotated datasets, severe data-imbalance, and minor difference in
appearances between fractured and healthy vertebrae make naive classification
approaches result in poor discriminatory performance. Addressing this, we
propose a representation learning-inspired approach for automated vertebral
fracture detection, aimed at learning latent representations efficient for
fracture detection. Building on state-of-art metric losses, we present a novel
Grading Loss for learning representations that respect Genant's fracture
grading scheme. On a publicly available spine dataset, the proposed loss
function achieves a fracture detection F1 score of 81.5%, a 10% increase over a
naive classification baseline.Comment: To be presented at MICCAI 202
Automatic Segmentation of Muscle Tissue and Inter-muscular Fat in Thigh and Calf MRI Images
Magnetic resonance imaging (MRI) of thigh and calf muscles is one of the most
effective techniques for estimating fat infiltration into muscular dystrophies.
The infiltration of adipose tissue into the diseased muscle region varies in
its severity across, and within, patients. In order to efficiently quantify the
infiltration of fat, accurate segmentation of muscle and fat is needed. An
estimation of the amount of infiltrated fat is typically done visually by
experts. Several algorithmic solutions have been proposed for automatic
segmentation. While these methods may work well in mild cases, they struggle in
moderate and severe cases due to the high variability in the intensity of
infiltration, and the tissue's heterogeneous nature. To address these
challenges, we propose a deep-learning approach, producing robust results with
high Dice Similarity Coefficient (DSC) of 0.964, 0.917 and 0.933 for
muscle-region, healthy muscle and inter-muscular adipose tissue (IMAT)
segmentation, respectively.Comment: 9 pages, 4 figures, 2 tables, MICCAI 2019, the 22nd International
Conference on Medical Image Computing and Computer Assisted Interventio
Opportunistic osteoporosis screening in multi-detector CT images via local classification of textures.
Our study proposed an automatic pipeline for opportunistic osteoporosis screening using 3D texture features and regional vBMD using multi-detector CT images. A combination of different local and global texture features outperformed the global vBMD and showed high discriminative power to identify patients with vertebral fractures.
INTRODUCTION
Many patients at risk for osteoporosis undergo computed tomography (CT) scans, usable for opportunistic (non-dedicated) screening. We compared the performance of global volumetric bone mineral density (vBMD) with a random forest classifier based on regional vBMD and 3D texture features to separate patients with and without osteoporotic fractures.
METHODS
In total, 154 patients (mean age 64 ± 8.5, male; n = 103) were included in this retrospective single-center analysis, who underwent contrast-enhanced CT for other reasons than osteoporosis screening. Patients were dichotomized regarding prevalent vertebral osteoporotic fractures (noFX, n = 101; FX, n = 53). Vertebral bodies were automatically segmented, and trabecular vBMD was calculated with a dedicated phantom. For 3D texture analysis, we extracted gray-level co-occurrence matrix Haralick features (HAR), histogram of gradients (HoG), local binary patterns (LBP), and wavelets (WL). Fractured vertebrae were excluded for texture-feature and vBMD data extraction. The performance to identify patients with prevalent osteoporotic vertebral fractures was evaluated in a fourfold cross-validation.
RESULTS
The random forest classifier showed a high discriminatory power (AUC = 0.88). Parameters of all vertebral levels significantly contributed to this classification. Importantly, the AUC of the proposed algorithm was significantly higher than that of volumetric global BMD alone (AUC = 0.64).
CONCLUSION
The presented classifier combining 3D texture features and regional vBMD including the complete thoracolumbar spine showed high discriminatory power to identify patients with vertebral fractures and had a better diagnostic performance than vBMD alone
Recommended from our members
Multicenter precision of cortical and trabecular bone quality measures assessed by high‐resolution peripheral quantitative computed tomography
High-resolution peripheral quantitative computed tomography (HR-pQCT) has recently been introduced as a clinical research tool for in vivo assessment of bone quality. The utility of this technology to address important skeletal health questions requires translation to standardized multicenter data pools. Our goal was to evaluate the feasibility of pooling data in multicenter HR-pQCT imaging trials. Reproducibility imaging experiments were performed using structure and composition-realistic phantoms constructed from cadaveric radii. Single-center precision was determined by repeat scanning over short-term (<72 hours), intermediate-term (3-5 months), and long-term intervals (28 months). Multicenter precision was determined by imaging the phantoms at nine different HR-pQCT centers. Least significant change (LSC) and root mean squared coefficient of variation (RMSCV) for each interval and across centers was calculated for bone density, geometry, microstructure, and biomechanical parameters. Single-center short-term RMSCVs were <1% for all parameters except cortical thickness (Ct.Th) (1.1%), spatial variability in cortical thickness (Ct.Th.SD) (2.6%), standard deviation of trabecular separation (Tb.Sp.SD) (1.8%), and porosity measures (6% to 8%). Intermediate-term RMSCVs were generally not statistically different from short-term values. Long-term variability was significantly greater for all density measures (0.7% to 2.0%; p < 0.05 versus short-term) and several structure measures: cortical thickness (Ct.Th) (3.4%; p < 0.01 versus short-term), cortical porosity (Ct.Po) (15.4%; p < 0.01 versus short-term), and trabecular thickness (Tb.Th) (2.2%; p < 0.01 versus short-term). Multicenter RMSCVs were also significantly higher than short-term values: 2% to 4% for density and micro-finite element analysis (µFE) measures (p < 0.0001), 2.6% to 5.3% for morphometric measures (p < 0.001), whereas Ct.Po was 16.2% (p < 0.001). In the absence of subject motion, multicenter precision errors for HR-pQCT parameters were generally less than 5%. Phantom-based multicenter precision was comparable to previously reported in in vivo single-center precision errors, although this was approximately two to five times worse than ex vivo short-term precision. The data generated from this study will contribute to the future design and validation of standardized procedures that are broadly translatable to multicenter study designs