5,010 research outputs found
Added value of morphological features to breast lesion diagnosis in ultrasound
Ultrasound imaging plays an important role in breast lesion differentiation.
However, diagnostic accuracy depends on ultrasonographer experience. Various
computer aided diagnosis systems has been developed to improve breast cancer
detection and reduce the number of unnecessary biopsies. In this study, our aim
was to improve breast lesion classification based on the BI-RADS (Breast
Imaging - Reporting and Data System). This was accomplished by combining the
BI-RADS with morphological features which assess lesion boundary. A dataset of
214 lesion images was used for analysis. 30 morphological features were
extracted and feature selection scheme was applied to find features which
improve the BI-RADS classification performance. Additionally, the best
performing morphological feature subset was indicated. We obtained a better
classification by combining the BI-RADS with six morphological features. These
features were the extent, overlap ratio, NRL entropy, circularity,
elliptic-normalized circumference and the normalized residual value. The area
under the receiver operating curve calculated with the use of the combined
classifier was 0.986. The best performing morphological feature subset
contained six features: the DWR, NRL entropy, normalized residual value,
overlap ratio, extent and the morphological closing ratio. For this set, the
area under the curve was 0.901. The combination of the radiologist's experience
related to the BI-RADS and the morphological features leads to a more effective
breast lesion classification.Comment: 7 pages, 3 figure
BIRADS Features-Oriented Semi-supervised Deep Learning for Breast Ultrasound Computer-Aided Diagnosis
Breast ultrasound (US) is an effective imaging modality for breast cancer
detection and diagnosis. US computer-aided diagnosis (CAD) systems have been
developed for decades and have employed either conventional hand-crafted
features or modern automatic deep-learned features, the former relying on
clinical experience and the latter demanding large datasets. In this paper, we
have developed a novel BIRADS-SDL network that integrates clinically-approved
breast lesion characteristics (BIRADS features) into semi-supervised deep
learning (SDL) to achieve accurate diagnoses with a small training dataset.
Breast US images are converted to BIRADS-oriented feature maps (BFMs) using a
distance-transformation coupled with a Gaussian filter. Then, the converted
BFMs are used as the input of an SDL network, which performs unsupervised
stacked convolutional auto-encoder (SCAE) image reconstruction guided by lesion
classification. We trained the BIRADS-SDL network with an alternative learning
strategy by balancing reconstruction error and classification label prediction
error. We compared the performance of the BIRADS-SDL network with conventional
SCAE and SDL methods that use the original images as inputs, as well as with an
SCAE that use BFMs as inputs. Experimental results on two breast US datasets
show that BIRADS-SDL ranked the best among the four networks, with
classification accuracy around 92.00% and 83.90% on two datasets. These
findings indicate that BIRADS-SDL could be promising for effective breast US
lesion CAD using small datasets
Automated Segmentation of Lesions in Ultrasound Using Semi-pixel-wise Cycle Generative Adversarial Nets
Breast cancer is the most common invasive cancer with the highest cancer
occurrence in females. Handheld ultrasound is one of the most efficient ways to
identify and diagnose the breast cancer. The area and the shape information of
a lesion is very helpful for clinicians to make diagnostic decisions. In this
study we propose a new deep-learning scheme, semi-pixel-wise cycle generative
adversarial net (SPCGAN) for segmenting the lesion in 2D ultrasound. The method
takes the advantage of a fully connected convolutional neural network (FCN) and
a generative adversarial net to segment a lesion by using prior knowledge. We
compared the proposed method to a fully connected neural network and the level
set segmentation method on a test dataset consisting of 32 malignant lesions
and 109 benign lesions. Our proposed method achieved a Dice similarity
coefficient (DSC) of 0.92 while FCN and the level set achieved 0.90 and 0.79
respectively. Particularly, for malignant lesions, our method increases the DSC
(0.90) of the fully connected neural network to 0.93 significantly (p0.001).
The results show that our SPCGAN can obtain robust segmentation results and may
be used to relieve the radiologists' burden for annotation
Semi-Automatic Segmentation and Ultrasonic Characterization of Solid Breast Lesions
Characterization of breast lesions is an essential prerequisite to detect
breast cancer in an early stage. Automatic segmentation makes this
categorization method robust by freeing it from subjectivity and human error.
Both spectral and morphometric features are successfully used for
differentiating between benign and malignant breast lesions. In this thesis, we
used empirical mode decomposition method for semi-automatic segmentation.
Sonographic features like ehcogenicity, heterogeneity, FNPA, margin definition,
Hurst coefficient, compactness, roundness, aspect ratio, convexity, solidity,
form factor were calculated to be used as our characterization parameters. All
of these parameters did not give desired comparative results. But some of them
namely echogenicity, heterogeneity, margin definition, aspect ratio and
convexity gave good results and were used for characterization
Algorithm guided outlining of 105 pancreatic cancer liver metastases in Ultrasound
Manual segmentation of hepatic metastases in ultrasound images acquired from
patients suffering from pancreatic cancer is common practice. Semiautomatic
measurements promising assistance in this process are often assessed using a
small number of lesions performed by examiners who already know the algorithm.
In this work, we present the application of an algorithm for the segmentation
of liver metastases due to pancreatic cancer using a set of 105 different
images of metastases. The algorithm and the two examiners had never assessed
the images before. The examiners first performed a manual segmentation and,
after five weeks, a semiautomatic segmentation using the algorithm. They were
satisfied in up to 90% of the cases with the semiautomatic segmentation
results. Using the algorithm was significantly faster and resulted in a median
Dice similarity score of over 80%. Estimation of the inter-operator variability
by using the intra class correlation coefficient was good with 0.8. In
conclusion, the algorithm facilitates fast and accurate segmentation of liver
metastases, comparable to the current gold standard of manual segmentation.Comment: 7 pages, 3 Figures, 3 Tables, 46 Reference
Clinical utility of gadobenate dimeglumine in contrast-enhanced MRI of the breast: a review
Breast magnetic resonance imaging (MRI) is considered the technique with the highest sensitivity for breast cancer detection. Gadobenate dimeglumine is a gadolinium-based contrast agent (GBCA) that is specifically approved in Europe for breast MRI and which has the highest r1 relaxivity among all GBCAs for this indication. In order to improve the diagnostic performance of breast MRI, several intra-individual crossover studies have evaluated gadobenate dimeglumine as a possible GBCA for this application. This review focuses on the role and advantages of gadobenate dimeglumine as a contrast agent for breast MRI by describing the unique properties of this agent and by summarizing published studies
SHEAR-net: An End-to-End Deep Learning Approach for Single Push Ultrasound Shear Wave Elasticity Imaging
Ultrasound Shear Wave Elastography (USWE) with conventional B-mode imaging
demonstrates better performance in lesion segmentation and classification
problems. In this article, we propose SHEAR-net, an end-to-end deep neural
network, to reconstruct USWE images from tracked tissue displacement data at
different time instants induced by a single acoustic radiation force (ARF) with
100% or 50% of the energy in conventional use. The SHEAR-net consists of a
localizer called the S-net to first localize the lesion location and then uses
recurrent layers to extract temporal correlations from wave patterns using
different time frames, and finally, with an estimator, it reconstructs the
shear modulus image from the concatenated outputs of S-net and recurrent
layers. The network is trained with 800 simulation and a limited number of CIRS
tissue mimicking phantom data and is optimized using a multi-task learning loss
function where the tasks are: inclusion localization and modulus estimation.
The efficacy of the proposed SHEAR-net is extensively evaluated both
qualitatively and quantitatively on 125 test set of motion data obtained from
simulation and CIRS phantoms. We show that the proposed approach consistently
outperforms the current state-of-the-art method and achieves overall 4-5 dB
improvement in PSNR and SNR. In addition, an average gain of 0.15 in DSC and
SSIM values indicate that the SHEAR-net has a better inclusion coverage area
and structural similarity of the two approaches. The proposed real-time deep
learning based technique can accurately estimate shear modulus for a minimum
tissue displacement of 0.5m and image multiple inclusions with a single
push ARF
Initial results of in vivo non-invasive cancer imaging in the human breast using near-infrared photoacoustics
Near-infrared photoacoustic images of regions-of-interest in 4 of the 5 cases of patients with symptomatic breasts reveal higher intensity regions which we attribute to vascular distribution associated with cancer. Of the 2 cases presented here, one is especially significant where benign indicators dominate in conventional radiological images, while photoacoustic images reveal vascular features suggestive of malignancy, which is corroborated by histopathology. The results show that photoacoustic imaging may have potential in visualizing certain breast cancers based on intrinsic optical absorption contrast. A future role for the approach could be in supplementing conventional breast imaging to assist detection and/or diagnosis.\ud
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Imaging beyond ultrasonically-impenetrable objects.
Ultrasound images are severely degraded by the presence of obstacles such as bones and air gaps along the beam path. This paper describes a method for imaging structures that are distal to obstacles that are otherwise impenetrable to ultrasound. The method uses an optically-inspired holographic algorithm to beam-shape the emitted ultrasound field in order to bypass the obstacle and place the beam focus beyond the obstruction. The resulting performance depends on the transducer aperture, the size and position of the obstacle, and the position of the target. Improvement compared to standard ultrasound imaging is significant for obstacles for which the width is larger than one fourth of the transducer aperture and the depth is within a few centimeters of the transducer. For such cases, the improvement in focal intensity at the location of the target reaches 30-fold, and the improvement in peak-to-side-lobe ratio reaches 3-fold. The method can be implemented in conventional ultrasound systems, and the entire process can be performed in real time. This method has applications in the fields of cancer detection, abdominal imaging, imaging of vertebral structure and ultrasound tomography. Here, its effectiveness is demonstrated using wire targets, tissue mimicking phantoms and an ex vivo biological sample
Radiological images and machine learning: trends, perspectives, and prospects
The application of machine learning to radiological images is an increasingly
active research area that is expected to grow in the next five to ten years.
Recent advances in machine learning have the potential to recognize and
classify complex patterns from different radiological imaging modalities such
as x-rays, computed tomography, magnetic resonance imaging and positron
emission tomography imaging. In many applications, machine learning based
systems have shown comparable performance to human decision-making. The
applications of machine learning are the key ingredients of future clinical
decision making and monitoring systems. This review covers the fundamental
concepts behind various machine learning techniques and their applications in
several radiological imaging areas, such as medical image segmentation, brain
function studies and neurological disease diagnosis, as well as computer-aided
systems, image registration, and content-based image retrieval systems.
Synchronistically, we will briefly discuss current challenges and future
directions regarding the application of machine learning in radiological
imaging. By giving insight on how take advantage of machine learning powered
applications, we expect that clinicians can prevent and diagnose diseases more
accurately and efficiently.Comment: 13 figure
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