Diagonal Difference Research Articles

In-situ Online Measurement of Rhombic Distortion in Billets

DD (diagonal-difference) is considered as measure of rhombic distortion, aka Rhomboidity, which is a shape related defect in square cross-section billets. Rhomboidity in billets starts with non-uniform shell solidification in the mold primarily due to inconsistent cooling causing irregular heat transfer. The higher diagonal difference greatly impacts the quality of billets to be rolled at various mills. Rhomboidity at or over 4% leads to billet twisting in the roughing stands of the rolling mill. Currently, billet rhomboidity is measured manually at end of casting operation. The presented work describes an optical, online & real-time image processing based method to determine the rhomboidity induced in each strand and alerts the operator to take corrective actions. The online Rhomboidity Measurement System employs sophisticated image acquisition & processing techniques to determine face contours of the billet with sub-pixel accuracy. The key features of RMS are the construction of a gaussian penalty function for selection of suitable 4-lines combination that precisely fits the billet face and use of a highly efficient and accurate statistical indicator, based on KL-Divergence measure, to estimate the rhomboidity even in presence of partial occlusion of billet face by scales. The expected savings are to the tune of 0.27 Million USD.

Prevalence of positional skull deformities in 530 premature infants with a corrected age of up to 6\u2009months: a multicenter study

BackgroundPositional deformities (PD) are common during early infancy. Severe cases may result in facial abnormalities and be associated with delayed neurological development in infants. The earlier the detection of PD, the better the intervention effect and the lower the cost of treatment. Currently, there are many studies on PD in Europe and the United States. However, in China, there is little data on the basic metrics and incidence of PD. Premature infants have a high risk of PD. However, there are few studies on PD in premature infants globally, and none in Asia. This study aimed to investigate PD and its characteristics inpremature infants to help its early detection and intervention and thus improve the quality of life for premature infants.MethodsWe analyzed 530 preterm infants who visited the outpatient departments at Xinqiao Hospital of Army Medical University and Maternal and Child Health Care Hospitals of Wanzhou and Yongchuan Districts in Chongqing from September 1, 2016, to August 31, 2017. The head shape data measured by a simple manual method were recorded. The diagonal difference (DD) between the transcranial diagonals and the cranial index (CI) was calculated. PD and its incidences indifferent gestational ages and corrected age groups were analyzed.ResultsAccording to previously defined international diagnostic criteria, the incidence of plagiocephaly, brachycephaly, and dolichocephaly were 51.1, 85.1, and 3.0% respectively, and those of right and left plagiocephalywere69.4 and 30.6%, respectively. The incidence of PD was highest among infants with a gestational age of < 32 weeks and decreased as the gestational age increased. As the corrected age (CA) increased, the incidence of plagiocephaly and dolichocephaly decreased, and the incidence of brachycephaly increased.ConclusionsPD incidence is high among preterm infants. As gestational age decreased, PD incidence and severity increased. Therefore, healthcare providers should implement early PD detection and intervention to prevent the adverse outcomes. The extremely high incidence of brachycephaly and extremely low incidence of dolichocephaly in this study are likely to be due to the variance of cranial metrics caused by cultural differences. The Chinese standards for infant cranial measurements must be established.

Accuracy of measurements used to quantify cranial asymmetry in deformational plagiocephaly

ObjectiveVarious measurements are used to quantify cranial asymmetry in deformational plagiocephaly (DP), but studies validating cut-off values and comparing the accuracy of such measurements are lacking. In this study, we compared the accuracy of four different measurements in classifying children with and without DP diagnosed by visual assessment, and sought to determine their optimal cut-off values. Study designTwo experts rated 407 3D craniofacial images of children aged between 3 and 36 months old using the Argenta classification. We then measured the following asymmetry-related variables from the images: Oblique Cranial Length Ratio (OCLR), Diagonal Difference (DD), Posterior Cranial Asymmetry Index (PCAI), and weighted Asymmetry Score (wAS). We created receiver operating characteristic curves to evaluate the accuracy of these variables. ResultsAll variables performed well, but OCLR consistently provided the best discrimination in terms of area under the curve values. Subject's age had no clear effect on the cut-off values for OCLR, PCAI, and wAS; however, the cut-off for DD increased monotonically with age. When subjects with discrepant expert ratings were excluded, the optimal cut-off values for DP (Argenta class ≥ 1) across all age-groups were 104.0% for OCLR (83% sensitivity, 97% specificity), 10.5% for PCAI (90% sensitivity, 90% specificity), and 24.5 for wAS (88% sensitivity, 90% specificity). ConclusionWe recommend using OCLR as the primary measurement, although PCAI and wAS may also be useful in monitoring cranial asymmetry. The threshold of relative asymmetry required for a deformation to appear clinically significant is not affected by the child's age, and DD has no additional utility in monitoring DP compared to using only OCLR.

Treatment Efficacy of Deformational Plagiocephaly and Brachiocephaly

INTRODUCTION: Although various treatments for deformational plagiocephaly (DP) and brachiocephaly (DB) have been well described, previous studies evaluating their efficacy are limited by small cohorts, inadequate follow-up, lack of reliable objective outcomes measures, and influence of commercial interests.1–3 This study analyzed the efficacy of repositioning, physical therapy (PT) and cranial molding in the treatment of DP/DB in a large, prospective cohort utilizing objective outcome measures. METHODS: All patients undergoing treatment of DP/DB between 2004 and 2010 were followed until cure or 18 months of age. Patients underwent either regimented conservative treatment (repositioning and/or PT) and/or cranial orthotic molding. Outcomes where measured objectively using a 3D laser surface scanner. Complete correction was defined as a cranial ratio (CR)<0.85 and diagonal difference (DD)<5mm. Independent risk factors for treatment failure were identified for each group by multivariate analysis. RESULTS: The study included 4,378 patients with DP/DB. Conservative treatment (repositioning and/or PT) was initiated in 3,381 infants, and cranial orthotic molding in 997 infants. Of patients initially treated conservatively, 22.9% failed management (15.8% required cranial molding, 7.1% had incomplete correction). Independent risk factors for conservative treatment failure included DP/DB severity (RR 1.31-1.64), advanced age (RR 1.20-2.08), torticollis (RR 1.12-1.74), developmental delay (RR 1.44) and poor treatment compliance (RR 2.4). Prematurity and male gender were non-risk factors; multiparity and vaginal delivery were protective. Ultimately, 1,531 patients underwent cranial orthotic molding (997 initially assigned, 534 failed conservative management), and 95.0% achieved complete correction. Independent risk factors for cranial orthotic molding failure included advanced age (RR 1.13-3.08) and poor treatment compliance (RR 3.01). CONCLUSION: Repositioning, PT, and cranial orthotic molding are effective treatments for DP/DB. Appropriate selection of a treatment modality requires evaluation of patient-specific risk factors. Cranial orthotic molding appears to isolate out intrinsic and environmental factors that increase the risk of conservative treatment failure.