Tai-Lang Jong

Self organizing map neural network with fuzzy screening for micro-calcifications detection on mammograms

Mammography remains the main screening tool for detecting breast cancer. Depicting micro-calcifications is one of the major roles of mammography. The purpose of the study is to utilize some image processing techniques to enhance the detection of micro-calcifications on mammograms. Discrete wavelet transform and difference of Gaussian filter were applied to enhance mammograms and hybrid of spatial and frequency features with self-organizing map of neural network were used to estimate the efficiency of locating micro-calcifications. In the enhancement process, the raw image was enhanced by gradient enhancement, mean contrast enhancement, and discrete wavelet transform and difference of Gaussian filter. Mean, variance, direct cosine transform coefficients, and entropy- these were extracted in the assessment stage. Finally, a self-organizing map neural network with fuzzy criterion classifier was adopted to classify the regions with similar characteristics. Twenty mammograms, with different mammographic patterns and densities, were evaluated with common agreement of the breast imaging reporting and data system categories by two radiologists in simulation. The survey revealed the micro-calcification regions had a good clustering property in self-organizing map neural network index.

Turner syndrome phalangeal screening based on a two-stage linear regression concept

Background:  Turner syndrome (TS) is a congenital chromosomal abnormality, resulting in short stature, short fourth metacarpal, and retarded skeletal maturation in children. The existing methods of diagnosis, which include carpal angle, metacarpal sign, and body mass index (BMI), cannot accurately diagnose TS. The authors propose a novel procedure for examining the hand skeleton to distinguish between normal individuals and patients with TS.

Long-term secular trend of skeletal maturation of Taiwanese children between agricultural (1960s) and contemporary (after 2000s) generations using the Tanner-Whitehouse 3 (TW3) method.

Abstract Background: The Tanner-Whitehouse (TW) method is one of the well-known techniques in determining the bone age. Objective: According to the objectivity of TW3, the secular trend was investigated to discover whether the skeletal maturation of Taiwanese children between two generations was different. Subjects and methods: The large-scale database of Taiwan was collected. The first group, called mid-1960s, included 265 boys and 295 girls in the agricultural generation (between 1966 and 1967). The second group, called mid-2000s, includes 114 boys and 616 girls in the contemporary generation (after 2000s). The bone age was determined by three radiologists using the carpals-only system of the TW3 method and by two physicians using the Greulich and Pyle method. A comparison of the means (independent-samples t-test) was applied by examining the difference of the children’s skeletal maturation between the two generations in the same chronological age. The significant difference was considered while the p-value was 0.05 or less (95% confidence interval). Results: A significant difference of the mean bone age (by, on average, three radiologists using the TW3 method) between the mid-1960s and mid-2000s in the same gender and chronological age was presented by the independent-samples t-test (p<0.001 with 95% confidence interval), and the bone age, determined by the TW3 method, of the mid-2000s group was higher than that of the mid-1960s group. This scenario corresponded with the children’s bone age determined by pediatricians. Besides, it deserved to notice that the bone age of boys in the mid-2000s was larger than that of the girls in the mid-1960s. Furthermore, by comparing the environmental condition, we suspect that the difference of bone age of children between the two generations was attributed to the discrepancy in nutrition and socioeconomic variation during the four decades in Taiwan. Conclusion: The study presents that the secular trend of skeletal maturation of children in the mid-2000s is faster than that in the mid-1960s.

Simplified radius, ulna, and short bone-age assessment procedure using grouped-Tanner-Whitehouse method

Background:  The Tanner–Whitehouse III (TW3) method is popular for assessing childrens bone age, but it is time‐consuming in clinical settings; to simplify this, a grouped‐TW algorithm (GTA) was developed.

Fast and fully automatic phalanx segmentation using a grayscale-histogram morphology algorithm

Bone age assessment is a common radiological examination used in pediatrics to diagnose the discrepancy between the skeletal and chronological age of a child; therefore, it is beneficial to develop a computer-based bone age assessment to help junior pediatricians estimate bone age easily. Unfortunately, the phalanx on radiograms is not easily separated from the background and soft tissue. Therefore, we proposed a new method, called the grayscale-histogram morphology algorithm, to segment the phalanges fast and precisely. The algorithm includes three parts: a tri-stage sieve algorithm used to eliminate the background of hand radiograms, a centroid-edge dual scanning algorithm to frame the phalanx region, and finally a segmentation algorithm based on disk traverse-subtraction filter to segment the phalanx. Moreover, two more segmentation methods: adaptive two-mean and adaptive two-mean clustering were performed, and their results were compared with the segmentation algorithm based on disk traverse-subtraction filter using five indices comprising misclassification error, relative foreground area error, modified Hausdorff distances, edge mismatch, and region nonuniformity. In addition, the CPU time of the three segmentation methods was discussed. The result showed that our method had a better performance than the other two methods. Furthermore, satisfactory segmentation results were obtained with a low standard error.

Carpal growth assessment based on fuzzy description

The article presents the fuzzy membership functions to evaluate the carpal growth maturity in pediatrics. Geometric condition of carpals was analyzed to extract the computerized features of carpals. In addition, principal component analysis was also recruited as the selector in de-fuzzy process. The resultant membership functions were sent into the bone age estimation to identify the efficiency. The simulation results indicated the misclassification of bone age was less than 10% within 1.5 years tolerance.

A study of video-based droplet detection

The disdrometer system is a new imaged-based technique developed to measure the shape of droplets. This system contains three components: a CCD camera for capturing video images, a backlight source for illuminating drops and enhancing images, and a control unit for data acquisition and function control. In our preliminary study, we replaced raindrops with a free fall of droplets from a homemade liquid dropper. Subsequently, the high-speed CCD camera captured images of the falling droplets. We controlled the exposure time to 1 ms, which resulted in the falling droplets blurring in the assessment. To detect the droplet contours precisely, we used Pascals theorem to determine the best-fit ellipse shape. We concluded that the proposed image-based disdrometer system provides a promising approach to measure and monitor the falling droplets. Moreover, this instrument can be less expensive as it only requires basic maintenance for long-lasting daily use.

Bone Age Pre-estimation Using Partial Least Squares Regression Analysis with a Priori Knowledge

Computerized bone age estimation was widely developed during near decade. There are many techniques were applied to this filed. In the study, a new concept, the partial least squares (PLS) regression analysis was proposed to pre-estimate the bone age as a priori knowledge. PLS is a multivariate statistical analysis method and can find combinations of the predictors that have a large covariance with the response values. One hundred and eleven radiograms with the third finger of the left hand were retrieved from DICOM system of Department of Radiology, Taipei Veterans General Hospital. The projection data of radiograms with the third finger were calculated, and then the normalized process was implemented. The discrete cosine transform (DCT) was employed to obtain components from projection data as features in this study. The first 30 components of DCT were selected as features. PLS was utilized to separate these features into four stages of skeleton maturation of children as a new application. The result of PLS regression presented that the average residual is 0.5. The study demonstrated a significant result that the PLS can successfully pre-estimate the bone age as a priori knowledge.

An easy-to-use TW3 system for assessing bone age

Precise and effective bone age assessment is important for pediatricians to diagnose children with endocrinological problems and growth disorders. The Tanner and Whitehouse III (TW3) method for determining bone age involves detailed shape analyses of several bones of interest and assigning corresponding scores, but the complexity and time-consuming nature make it hard to apply in clinic. Therefore, our project is to develop an easy-to-use graphical user interface which can automatically localize and segment the phalanx region of interests (PROIs) and the epiphyseal/metaphyseal region of interests (EMROIs) of the left-hand radiogram, and then a TW3 scoring system is provided to the user to make a decision. Based on this system, a set of image processing procedures was proposed for the segmentation of PROIs and EMROIs, and then 8 EMORIs were consecutively popped up for the evaluation of TW3 scores. Subsequently, each score of 8 EMROIs was accumulated automatically until the operations were completed. We believed that the easy-to-use TW3 system serves a better operational tool for the pediatricians.

A hierarchical algorithm for phalangeal and epiphyseal/metaphyseal segmentation

Computerized bone age assessment was widely studied for the physicians and radiologists to evaluate children with endocrinological disorders, growth retardation and treatment monitoring. Unfortunately, the morphological assessment of phalanges and epiphyseal/metaphyseal region (EMROIs) in hand radiogram with non-uniform intensity or full of the noise is intricacies and hardly to be segmented, and which was also time-consuming. So, a new segmentation technique for handy skeleton was proposed. The first step, the properties of position and brightness on phalanges and EMORIs are analyzed by a series of image preprocessing procedures. Next, 14 EMORIs of five phalanges were examined by the sum-variance (SV) scheme for the 100 boys and 100 girls. Last, four statistical indices are used to evaluate the segmentation. The experiment performance is shown the better result than the gradient vector flow (GVF) snake, and the approximation of adaptive two-means clustering. The study showed the proposed hierarchical algorithm for the extraction and segmentation of phalangeal bone regions of interests (PROIs) and EMROIs are effective, especially for the EMROIs segmentation by using the proposed algorithm.