A basis function feature‐based approach for skin lesion discrimination in dermatology dermoscopy images

Background: Skin lesion color is an important feature for diagnosing malignant melanoma. New basis function correlation features are proposed for discriminating malignant melanoma lesions from benign lesions in dermoscopy images. The proposed features are computed based on correlating the luminance histogram of melanoma or benign labeled relative colors from a specified portion of the skin lesion with a set of basis functions. These features extend previously developed statistical and fuzzy logic‐based relative color histogram analysis techniques for automated mapping of colors representative of melanoma and benign skin lesions from a training set of lesion images. Methods: Using the statistical and fuzzy logic‐based approaches for relative color mapping, melanoma and benign color features are computed over skin lesion region of interest, respectively. Luminance histograms are obtained from the melanoma and benign mapped colors within the lesion region of interest and are correlated with a set of basis functions to quantify the distribution of colors. The histogram analysis techniques and feature calculations are evaluated using a data set of 279 malignant melanomas and 442 benign dysplastic nevi images. Results: Experimental test results showed that combining existing melanoma and benign color features with the proposed basis function features found from the melanoma mapped colors yielded average correct melanoma and benign lesion discrimination rates as high as 86.45% and 83.35%, respectively. Conclusions: The basis function features provide an alternative approach to melanoma discrimination that quantifies the variation and distribution of colors characteristic of melanoma and benign skin lesions.     

Detection of asymmetric blotches (asymmetric structureless areas) in dermoscopy images of malignant melanoma using relative color

BACKGROUND: Dermoscopy, also known as dermatoscopy or epiluminescence microscopy (ELM), is a non-invasive, in vivo technique, which permits visualization of features of pigmented melanocytic neoplasms that are not discernable by examination with the naked eye. One prominent feature useful for melanoma detection in dermoscopy images is the asymmetric blotch (asymmetric structureless area). METHOD: Using both relative and absolute colors, blotches are detected in this research automatically by using thresholds in the red and green color planes. Several blotch indices are computed, including the scaled distance between the largest blotch centroid and the lesion centroid, ratio of total blotch areas to lesion area, ratio of largest blotch area to lesion area, total number of blotches, size of largest blotch, and irregularity of largest blotch. RESULTS: The effectiveness of the absolute and relative color blotch features was examined for melanoma/benign lesion discrimination over a dermoscopy image set containing 165 melanomas (151 invasive melanomas and 14 melanomas in situ) and 347 benign lesions (124 nevocellular nevi without dysplasia and 223 dysplastic nevi) using a leave-one-out neural network approach. Receiver operating characteristic curve results are shown, highlighting the sensitivity and specificity of melanoma detection. Statistical analysis of the blotch features are also presented. CONCLUSION: Neural network and statistical analysis showed that the blotch detection method was somewhat more effective using relative color than using absolute color. The relative-color blotch detection method gave a diagnostic accuracy of about 77%.     

Detection of basal cell carcinoma using color and histogram measures of semitranslucent areas

Background: Semitranslucency, defined as a smooth, jelly-like area with varied, near-skin-tone color, can indicate a diagnosis of basal cell carcinoma (BCC) with high specificity. This study sought to analyze potential areas of semitranslucency with histogram-derived texture and color measures to discriminate BCC from non-semitranslucent areas in non-BCC skin lesions.
Methods: For 210 dermoscopy images, the areas of semitranslucency in 42 BCCs and comparable areas of smoothness and color in 168 non-BCCs were selected manually. Six color measures and six texture measures were applied to the semitranslucent areas of the BCC and the comparable areas in the non-BCC images.
Results: Receiver operating characteristic (ROC) curve analysis showed that the texture measures alone provided greater separation of BCC from non-BCC than the color measures alone. Statistical analysis showed that the four most important measures of semitranslucency are three histogram measures: contrast, smoothness, and entropy, and one color measure: blue chromaticity. Smoothness is the single most important measure. The combined 12 measures achieved a diagnostic accuracy of 95.05% based on area under the ROC curve.
Conclusion: Texture and color analysis measures, especially smoothness, may afford automatic detection of BCC images with semitranslucency.     

Incremental Cost-Effectiveness of 13-valent Pneumococcal Conjugate Vaccine for Adults Age 50 Years and Older in the United States

BACKGROUND

Recently released results from a randomized controlled trial have shown that 13-valent pneumococcal conjugate vaccine (PCV13) is efficacious against vaccine-type nonbacteremic pneumonia in adults.

OBJECTIVE

We examined the incremental cost-effectiveness of adding PCV13 to the Advisory Committee on Immunization Practices (ACIP) adult immunization schedule.

METHODS

We used a probabilistic model following cohorts of 50-, 60-, or 65-year-olds. We used separate vaccination coverage and disease incidence data for healthy and high-risk adults. Incremental cost-effectiveness ratios were determined for each potential vaccination strategy.

RESULTS

In the base case scenario, our model indicated that adding PCV13 at age 65 or replacing 23-valent pneumococcal polysaccharide vaccine (PPSV23) at age 65 with PCV13 provided more value for money than adding PCV13 at ages 50 or 60. After projections of six additional years of herd protection from the childhood immunization program were incorporated, we found adding PCV13 dominated replacing PPSV23. For a cohort of 65-year-olds in 2013, the cost of adding PCV13 at age 65 to the schedule was $62,065 per quality-adjusted life year (QALY) gained, which rose to $272,621 after 6 years of projected herd protection.

CONCLUSION

The addition of one dose of PCV13 for adults appears to have a cost-effectiveness ratio comparable to other vaccination interventions in the short run, though anticipated herd protection from the childhood immunization program may dramatically increase the cost per QALY after only a few years.

     

Multiple Biomarkers of Maternal Iron Predict Infant Cognitive Outcomes

This study examined relations between multiple measures of maternal iron status assessed 3 months post-partum, and infant processing speed (longest look during visual habituation), memory (novelty preference), attention (heart rate changes), and neural response variability (in auditory event-related potentials) at 3 and 9 months. Plasma iron was associated with 9-month novelty preference and longest look, and developmental changes in longest look. Hemoglobin predicted sustained attention, and both plasma iron and soluble transferrin receptors predicted neural response variability at 9 months. Improved maternal iron appears to have a positive impact on infant cognitive development even in a well-nourished, low-risk sample.     

Fetal and Childhood Growth Patterns Associated with Bone Mass in School‐Age Children: The Generation R Study

Low birth weight is associated with lower bone accrual in children and peak bone mass in adults. We assessed how different patterns of longitudinal fetal and early childhood growth influence bone properties at school age. In 5431 children participating in a population‐based prospective cohort study, we measured fetal growth by ultrasound at 20 and 30 weeks gestation, and childhood growth at birth, 1, 2, 3, and 4 years of age. We analyzed these growth measurements in relation to total body (less head) BMD measured by DXA at age 6. We used conditional growth modeling; a technique which takes into account correlation between repeatedly measured growth measures. Our results showed that estimated fetal weight gain, femur length growth between 20 and 30 weeks of gestation, femur length growth between 30 weeks and birth, as well as all height and weight growth measurements from birth to 4 years of age were all positively associated with BMC, bone area (BA), and BMD (all p < 0.01). Fetal femur length growth between 30 weeks and birth was positively associated with BMC and BA (both p < 0.001), but not with BMD. Overall, childhood growth measurements exerted a larger influence on bone measures than fetal growth measures. The strongest effect estimate was observed during the first year of life. Children born small (<10th percentile) for gestational age (SGA) had lower BMC and BA, but not BMD, than children born appropriate for gestational age (AGA), whereas children born large (>90th percentile) for gestational age (LGA) had higher BMC and BA (all p < 0.001). These differences were no longer present in children showing subsequent accelerated and decelerated infant growth, respectively. We conclude that both fetal and childhood growth patterns are associated with bone mineral accrual, showing the strongest effect estimates in infancy . Compensatory infant growth counteracts the adverse consequences of fetal growth restriction on bone development. © 2014 American Society for Bone and Mineral Research.     

An improved objective evaluation measure for border detection in dermoscopy images

Background: Dermoscopy is one of the major imaging modalities used in the diagnosis of melanoma and other pigmented skin lesions. Owing to the difficulty and subjectivity of human interpretation, dermoscopy image analysis has become an important research area. One of the most important steps in dermoscopy image analysis is the automated detection of lesion borders. Although numerous methods have been developed for the detection of lesion borders, very few studies were comprehensive in the evaluation of their results.
Methods: In this paper, we evaluate five recent border detection methods on a set of 90 dermoscopy images using three sets of dermatologist-drawn borders as the ground truth. In contrast to previous work, we utilize an objective measure, the normalized probabilistic rand index, which takes into account the variations in the ground-truth images.
Conclusion: The results demonstrate that the differences between four of the evaluated border detection methods are in fact smaller than those predicted by the commonly used exclusive-OR measure.     

Automatic lesion boundary detection in dermoscopy images using gradient vector flow snakes

BACKGROUND: Malignant melanoma has a good prognosis if treated early. Dermoscopy images of pigmented lesions are most commonly taken at x 10 magnification under lighting at a low angle of incidence while the skin is immersed in oil under a glass plate. Accurate skin lesion segmentation from the background skin is important because some of the features anticipated to be used for diagnosis deal with shape of the lesion and others deal with the color of the lesion compared with the color of the surrounding skin. METHODS: In this research, gradient vector flow (GVF) snakes are investigated to find the border of skin lesions in dermoscopy images. An automatic initialization method is introduced to make the skin lesion border determination process fully automated. RESULTS: Skin lesion segmentation results are presented for 70 benign and 30 melanoma skin lesion images for the GVF-based method and a color histogram analysis technique. The average errors obtained by the GVF-based method are lower for both the benign and melanoma image sets than for the color histogram analysis technique based on comparison with manually segmented lesions determined by a dermatologist. CONCLUSIONS: The experimental results for the GVF-based method demonstrate promise as an automated technique for skin lesion segmentation in dermoscopy images.     

扶正中药联合化疗对Ⅲ-Ⅳ期结直肠癌患者生存期影响的Meta分析

目的:系统评价扶正中药联合化疗对III-IV期结直肠癌患者生存期的影响。方法:计算机检索中国生物医学文献数据库、CNKI、VIP、万方数据库,收集扶正中药联合化疗与单用化疗比较对III-IV期结直肠癌患者生存期影响的随机对照试验。对资料进行质量评价,用Rev Man 5.2进行Meta分析。结果:共检索到符合纳入标准的中文文献10篇867例患者。文献质量Jadad评分结果显示4篇文献为3分,6篇文献为2分。Meta分析:一年生存率OR3.10,95%[2.10,4.57],P<0.0001;两年生存率OR 2.38,95%[1.53,3.70],P=0.0001;三年生存率OR2.32,95%[1.35,3.98],P=0.002;差异具有统计学意义。四年、五年生存率差异无统计学意义。结论:扶正中药联合化疗在延长结直肠癌患者生存期与单纯化疗相比有一定的优势。受纳入文献的方法学质量和样本量限制,上述结论尚待开展更多大样本、高质量研究予以证实。