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.
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%.
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.
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%.
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.
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.
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