Lesion segmentation in medical images, particularly for Bone Marrow Edema-like Lesions (BMEL) in the knee, faces challenges due to imbalanced data and unreliable annotations. This study proposes an unsupervised deep learning method with the use of conditional diffusion models coupled with inpainting tasks for anomaly detection. This innovative approach facilitates the detection and segmentation of BMEL without human intervention, achieving a DICE testing score of 0.2223. BMEL has been shown to correlate and predict disease progression in several musculoskeletal disorders, such as osteoarthritis. With further development, our method has great potential for fully automated analysis of BMEL to improve early diagnosis and prognosis for musculoskeletal disorders. The framework can be extended to other lesion detection as well.
Adult Spinal Deformity is a prominent medical issue with about 68% of the elderly population suffering from the disease.1 Detailed biomechanical assessment is needed both in the presurgical planning of structural spinal deformity as well as in early functional biomechanical compensation in ambulatory spinal pain patients. When considering automation of this process, we have to look at photographic intervertebral disc detection technique as a way to produce a detailed model of the spine with appropriate measurements required to make efficient and accurate decisions on patient care. Deep convolutional neural network (CNN) has given remarkable results in object recognition tasks in recent years. However, massive training data, computational resources and long training time is needed for both training a deep network from scratch or finetuning a network. Using pretrained model as feature extractor has shown promising result for moderate sized medical data.2 However, most work have extracted features from the last layer and little has been explored in terms of the number of convolutional layers needed for best performance. In this work we trained Support Vector Machine (SVM) classifiers on different layers of CaffeNet3 features to show that deeper the better concept does not hold for task such as intervertebral disc detection. Furthermore, our experimental results show the potential of using very small training data, such as 15 annotated medical images in our experiment, to yield satisfactory classification performance with accuracy up to 97.2%.
Cytogenetic abnormalities are important diagnostic and prognostic criteria for acute myeloid leukemia (AML). A flow cytometry-based imaging approach for FISH in suspension (FISH-IS) was established that enables the automated analysis of several log-magnitude higher number of cells compared to the microscopy-based approaches. The rotational positioning can occur leading to discordance between spot count. As a solution of counting error from overlapping spots, in this study, a Gaussian Mixture Model based classification method is proposed. The Akaike information criterion (AIC) and Bayesian information criterion (BIC) of GMM are used as global image features of this classification method. Via Random Forest classifier, the result shows that the proposed method is able to detect closely overlapping spots which cannot be separated by existing image segmentation based spot detection methods. The experiment results show that by the proposed method we can obtain a significant improvement in spot counting accuracy.
KEYWORDS: Magnetic resonance imaging, Feature extraction, Convolution, Neural networks, Computer aided diagnosis and therapy, CAD systems, Imaging systems, Picture Archiving and Communication System, 3D magnetic resonance imaging, Convolutional neural networks
In this paper, we explore the importance of axial lumbar MRI slices for automatic detection of abnormalities. In the past, only the sagittal views were taken into account for lumbar CAD systems, ignoring the fact that a radiologist scans through the axial slices as well, to confirm the diagnosis and quantify various abnormalities like herniation and stenosis. Hence, we present an automatic diagnosis system from axial slices using CNN(Convolutional Neural Network) for dynamic feature extraction and classification of normal and abnormal lumbar discs. We show 80:81% accuracy (with a specificity of 85:29% and sensitivity of 75:56%) on 86 cases (391 discs) using only an axial slice for each disc, which implies the usefulness of axial views for automatic lumbar abnormality diagnosis in conjunction with sagittal views.
Nuclei counting in epithelial cells is an indication for tumor proliferation rate which is useful to rank
tumors and select an appropriate treatment schedule for the patient. However, due to the high interand
intra- observer variability in nuclei counting, pathologists seek a deterministic proliferation rate
estimate. Histology tissue contains epithelial and stromal cells. However, nuclei counting is clinically
restricted to epithelial cells because stromal cells do not become cancerous themselves since
they remain genetically normal. Counting nuclei existing within the stromal tissue is one of the major
causes of the proliferation rate non-deterministic estimation. Digitally removing stromal tissue
will eliminate a major cause in pathologist counting variability and bring the clinical pathologist a
major step closer toward a deterministic proliferation rate estimation. To that end, we propose a
computer aided diagnosis (CAD) system for eliminating stromal cells from digital histology images
based on the local binary patterns, entropy measurement, and statistical analysis. We validate our
CAD system on a set of fifty Ki-67-stained histology images. Ki-67-stained histology images are
among the clinically approved methods for proliferation rate estimation. To test our CAD system,
we prove that the manual proliferation rate estimation performed by the expert pathologist does not
change before and after stromal removal. Thus, stromal removal does not affect the expert pathologist
estimation clinical decision. Hence, the successful elimination of the stromal area highly reduces
the false positive nuclei which are the major confusing cause for the less experienced pathologists
and thus accounts for the non-determinism in the proliferation rate estimation. Our experimental
setting shows statistical insignificance (paired student t-test shows ρ = 0.74) in the manual nuclei
counting before and after our automated stromal removal. This means that the clinical decision of
the expert pathologist is not affected by our CAD system which is what we want to prove. However,
the usage of our CAD system substantially account for the reduced inter- and intra- proliferation
rate estimation variability and especially for less-experienced pathologists.
Breast cancer is the second cause of women death and the most diagnosed female cancer in the US. Proliferation rate
estimation (PRE) is one of the prognostic indicators that guide the treatment protocols and it is clinically performed from
Ki-67 histopathology images. Automating PRE substantially increases the efficiency of the pathologists. Moreover,
presenting a deterministic and reproducible proliferation rate value is crucial to reduce inter-observer variability. To that
end, we propose a fully automated CAD system for PRE from the Ki-67 histopathology images. This CAD system is
based on a model of three steps: image pre-processing, image clustering, and nuclei segmentation and counting that are
finally followed by PRE. The first step is based on customized color modification and color-space transformation. Then,
image pixels are clustered by K-Means depending on the features extracted from the images derived from the first step.
Finally, nuclei are segmented and counted using global thresholding, mathematical morphology and connected
component analysis. Our experimental results on fifty Ki-67-stained histopathology images show a significant agreement
between our CAD's automated PRE and the gold standard's one, where the latter is an average between two observers'
estimates. The Paired T-Test, for the automated and manual estimates, shows ρ = 0.86, 0.45, 0.8 for the brown nuclei
count, blue nuclei count, and proliferation rate, respectively. Thus, our proposed CAD system is as reliable as the
pathologist estimating the proliferation rate. Yet, its estimate is reproducible.
An imaging test has an important role in the diagnosis of lumbar abnormalities since it allows to examine the internal
structure of soft tissues and bony elements without the need of an unnecessary surgery and recovery time. For the past
decade, among various imaging modalities, magnetic resonance imaging (MRI) has taken the significant part of the clinical
evaluation of the lumbar spine. This is mainly due to technological advancements that lead to the improvement of imaging
devices in spatial resolution, contrast resolution, and multi-planar capabilities. In addition, noninvasive nature of MRI
makes it easy to diagnose many common causes of low back pain such as disc herniation, spinal stenosis, and degenerative
disc diseases. In this paper, we propose a method to diagnose lumbar spinal stenosis (LSS), a narrowing of the spinal canal,
from magnetic resonance myelography (MRM) images. Our method segments the thecal sac in the preprocessing stage,
generates the features based on inter- and intra-context information, and diagnoses lumbar disc stenosis. Experiments with
55 subjects show that our method achieves 91.3% diagnostic accuracy. In the future, we plan to test our method on more
subjects.
Lumbar vertebral fractures vary greatly in types and causes and usually result from severe trauma or pathological
conditions such as osteoporosis. Lumbar wedge compression fractures are amongst the most common ones where
the vertebra is severely compressed forming a wedge shape and causing pain and pressure on the nerve roots
and the spine. Since vertebral segmentation is the first step in any automated diagnosis task, we present a fully
automated method for robustly localizing and segmenting the vertebrae for preparation of vertebral fracture
diagnosis. Our segmentation method consists of five main steps towards the CAD(Computer-Aided Diagnosis)
system: 1) Localization of the intervertebral discs. 2) Localization of the vertebral skeleton. 3) Segmentation
of the individual vertebra. 4) Detection of the vertebrae center line and 5) Detection of the vertebrae major
boundary points. Our segmentation results are promising with an average error of 1.5mm (modified Hausdorff
distance metric) on 50 clinical CT cases i.e. a total of 250 lumbar vertebrae. We also present promising
preliminary results for automatic wedge compression fracture diagnosis on 15 cases, 7 of which have one or more
vertebral compression fracture, and obtain an accuracy of 97.33%.
Intervertebral disc herniation is a major reason for lower back pain (LBP), which is the second most common
neurological ailment in the United States. Automation of herniated disc diagnosis reduces the large burden
on radiologists who have to diagnose hundreds of cases each day using clinical MRI. We present a method
for automatic diagnosis of lumbar disc herniation using appearance and shape features. We jointly use the
intensity signal for modeling the appearance of herniated disc and the active shape model for modeling the
shape of herniated disc. We utilize a Gibbs distribution for classification of discs using appearance and shape
features. We use 33 clinical MRI cases of the lumbar area for training and testing both appearance and shape
models. We achieve over 91% accuracy in detection of herniation in a cross-validation experiment with specificity
of 91% and sensitivity of 94%.
In recent years the demand for an automated method for diagnosis of disc abnormalities has grown as more
patients suffer from lumbar disorders and radiologists have to treat more patients reliably in a limited amount of
time. In this paper, we propose and compare several classifiers that diagnose disc herniation, one of the common
problems of the lumbar spine, based on lumbar MR images. Experimental results on a limited data set of 68
clinical cases with 340 lumbar discs show that our classifiers can diagnose disc herniation with 97% accuracy.
High resolution digital pathology images have a wide range of variability in color, shape, size, number, appearance,
location, and texture. The segmentation problem is challenging in this environment. We introduce a hybrid method that combines parametric machine learning with heuristic methods for feature extraction as well as pre- and post-processing steps for localizing diverse tissues in slide images. The method uses features such
as color, intensity, texture, and spatial distribution. We use principal component analysis for feature reduction and train a two layer back propagation neural network (with one hidden layer). We perform image labeling at pixel-level and achieve higher than 96% automatic localization accuracy on 294 test images.
We present a new method for automatic detection of the lumbar vertebrae and disk structure from MR images.
In clinical settings, radiologists utilize several images of the lumbar structure for diagnosis of lumbar disorders.
These images are co-registered by technicians and represent orthogonal features of the lumbar region. We
combine information from T1W sagittal, T2W sagittal and T2W axial MR images to automatically label disks
and vertebral columns. The method couples geometric and tissue property information available from the three
types of images with image analysis approaches to achieve 98.8% accuracy for the disk labeling task on a test
set of 67 images containing 335 disks.
Reliable segmentation of the liver has been acknowledged as a significant step in several computational and
diagnostic processes. While several methods have been designed for liver segmentation, comparative analysis
of reported methods is limited by the unavailability of annotated datasets of the abdominal area. Currently
available generic data-sets constitute a small sample set, and most academic work utilizes closed datasets. We
have collected a dataset containing abdominal CT scans of 50 patients, with coordinates for the liver boundary.
The dataset will be publicly distributed free of cost with software to provide similarity metrics, and a liver
segmentation technique that uses Markov Random Fields and Active Contours. In this paper we discuss our
data collection methodology, implementation of similarity metrics, and the liver segmentation algorithm.
Esophageal ultrasound (EUS) is particularly useful for isolating lymph nodes in the N-staging of esophageal
cancer, a disease with very poor overall prognosis. Although EUS is relatively low-cost and real time, and it
provides valuable information to the clinician, its usefulness to less trained "users" including opportunities for
computer-aided diagnosis is still limited due to the strong presence of spatially correlated interference noise
called speckles. To this end, in this paper, we present a technique for enhancing lymph nodes in EUS images
by first reducing the spatial correlation of the specular noise and then using a modified structured tensor-based
anisotropic filter to complete the speckle reduction process. We report on a measure of the enhancement and
also on the extent of automatic processing possible, after the speckle reduction process has taken place. Also, we
show the limitations of the enhancement process by extracting relevant lymph node features from the despeckled
images. When tested on five representative classes of esophageal lymph nodes, we found the despeckling process
to greatly reduce the specularity of the original EUS images, therefore proving very useful for visualization
purposes. But it still requires additional work for the complete automation of the lymph node characterizing
process.
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