Incorporation of a biparietal narrowing metric to improve the ability of machine learning models to detect sagittal craniosynostosis with 2D photographs.

OBJECTIVE: Sagittal craniosynostosis is the most common form of craniosynostosis and typically results in scaphocephaly, which is characterized by biparietal narrowing, compensatory frontal bossing, and an occipital prominence. The cephalic index (CI) is a simple metric for quantifying the degree of cranial narrowing and is often used to diagnose sagittal craniosynostosis. However, patients with variant forms of sagittal craniosynostosis may present with a "normal" CI, depending on the part of the suture that is closed. As machine learning (ML) algorithms are developed to assist in the diagnosis of cranial deformities, metrics that reflect the other phenotypic features of sagittal craniosynostosis are needed. In this study the authors sought to describe the posterior arc angle (PAA), a measurement of biparietal narrowing that is obtained with 2D photographs, and elucidate the role of PAA as an adjuvant to the CI in characterizing scaphocephaly and the potential relevance of PAA in new ML model development. METHODS: The authors retrospectively reviewed 1013 craniofacial patients treated during the period from 2006 to 2021. Orthogonal top-down photographs were used to calculate the CI and PAA. Distribution densities, receiver operating characteristic (ROC) curves, and chi-square analyses were used to describe the relative predictive utility of each method for sagittal craniosynostosis. RESULTS: In total, 1001 patients underwent paired CI and PAA measurements and a clinical head shape diagnosis (sagittal craniosynostosis, n = 122; other cranial deformity, n = 565; normocephalic, n = 314). The area under the ROC curve (AUC) for the CI was 98.5% (95% confidence interval 97.8%-99.2%, p < 0.001), with an optimum specificity of 92.6% and sensitivity of 93.4%. The PAA had an AUC of 97.4% (95% confidence interval 96.0%-98.8%, p < 0.001) with an optimum specificity of 94.9% and sensitivity of 90.2%. In 6 of 122 (4.9%) cases of sagittal craniosynostosis, the PAA was abnormal while the CI was normal. This means that adding a PAA cutoff branch to a partition model increases the detection of sagittal craniosynostosis. CONCLUSIONS: Both CI and PAA are excellent discriminators for sagittal craniosynostosis. Using an accuracy-optimized partition model, the addition of the PAA to the CI increased model sensitivity compared to using the CI alone. Using a model that incorporates both CI and PAA could assist in the early identification and treatment of sagittal craniosynostosis via automated and semiautomated algorithms that utilize tree-based ML models.

Impact of Calcium Quantifications on Stent Expansions.

Severely calcified plaque is of great concern when planning and implementing a stenting intervention. In this work, computational models were developed to investigate the influence of calcium characteristics on stenting outcomes. The commonly used clinical measurements of calcium (i.e., the arc angle, maximum thickness, length, and volume) were varied to estimate stenting outcomes in terms of lumen gain, stent underexpansion, strut malapposition, and stress or strain distributions of the stenotic lesion. Results have shown that stenting outcomes were most sensitive to the arc angle of the calcium. A thick calcium with a large arc angle resulted in poor stenting outcomes, such as severe stent underexpansion, D-shaped lumen, increased strut malapposition, and large stresses or strains in the plaque. This was attributed to the circumferential stretch of the tissue. Specifically, the noncalcium component was stretched significantly more than the calcium. The circumferential stretch ratios of calcium and noncalcium component were approximately 1.44 and 2.35, respectively, regardless of calcium characteristics. In addition, the peak stress or strain within the artery and noncalcium component of the plaque occurred at the area adjacent to calcium edges (i.e., the interface between the calcium and the noncalcium component) coincident with the location of peak malapposition. It is worth noting that calcium played a protective role for the artery underneath, which was at the expense of the overstretch and stress concentrations in the other portion of the artery. These detailed mechanistic quantifications could be used to provide a fundamental understanding of the impact of calcium quantifications on stent expansions, as well as to exploit their potential for a better preclinical strategy.

Efficacy of robust optimization plan with partial-arc VMAT for photon volumetric-modulated arc therapy: A phantom study.

This study investigated position dependence in planning target volume (PTV)-based and robust optimization plans using full-arc and partial-arc volumetric modulated arc therapy (VMAT). The gantry angles at the periphery, intermediate, and center CTV positions were 181°-180° (full-arc VMAT) and 181°-360° (partial-arc VMAT). A PTV-based optimization plan was defined by 5 mm margin expansion of the CTV to a PTV volume, on which the dose constraints were applied. The robust optimization plan consisted of a directly optimized dose to the CTV under a maximum-uncertainties setup of 5 mm. The prescription dose was normalized to the CTV D99% (the minimum relative dose that covers 99% of the volume of the CTV) as an original plan. The isocenter was rigidly shifted at 1 mm intervals in the anterior-posterior (A-P), superior-inferior (S-I), and right-left (R-L) directions from the original position to the maximum-uncertainties setup of 5 mm in the original plan, yielding recalculated dose distributions. It was found that for the intermediate and center positions, the uncertainties in the D99% doses to the CTV for all directions did not significantly differ when comparing the PTV-based and robust optimization plans (P > 0.05). For the periphery position, uncertainties in the D99% doses to the CTV in the R-L direction for the robust optimization plan were found to be lower than those in the PTV-based optimization plan (P < 0.05). Our study demonstrated that a robust optimization plan's efficacy using partial-arc VMAT depends on the periphery CTV position.

Part 2: outcome of acetabular fractures and associated prognostic factors-a ten-year retrospective study of one hundred and fifty six operated cases with open reduction and internal fixation.

QUESTIONS/PURPOSES: The aim of this study was to identify prognostic factors associated with a poor quality of reduction and their relationships. METHODS: Data from medical charts for all patients admitted with acetabular fractures operated by open reduction and internal fixation (ORIF) from 2005 to 2014 were extracted. A total of 156 patients with a mean age of 40.3 years were included. All patients were reviewed at six months of follow-up. The prognostic factors analyzed were clinical and radiological factors. A new radiological parameter was also studied: the scanographic roof-arc angle. Specific statistical analysis was performed using a logistic regression model. RESULTS: Using a multivariate analysis logistic regression model: roof impaction (p = 0.001; OR = 6.59; CI 95% [2.01-20.97]), transverse + posterior wall (p = 0.03, OR = 2.52; CI 95% [1.46-13.65]) and surgeons in training (p = 0.02; OR = 1.24; CI 95% [1.07-3.32]) were three independent prognostic factors. Lower values of medial and posterior scanographic roof-arc angle were associated with unsatisfactory reduction. A significant association between unsatisfactory reduction and posterior roof arc angle < 61° was found. CONCLUSIONS: Three independent prognostic factors associated with a risk of unsatisfactory reduction in ORIF for acetabular fractures were identified: roof impaction, transverse + posterior wall fracture and surgeons in training. Scanographic roof-arc angle seems to be a new prognostic factor. Level of Evidence Level 4 retrospective study.

Shots at goal in Australian Football: Historical trends, determinants of accuracy and common strategies.

OBJECTIVES: To understand the historical context of and relationships between, the characteristics of shots at goal and match outcome in the Australian Football League. DESIGN: Observational. METHODS: Descriptive statistics of shots at goal were calculated and compared across 20 seasons. The location, type, and outcome of all shots at goal (n = 43,254), by all teams (2017-19 & 21), were compared with match outcome. RESULTS: The total number of shots per match and the accuracy of shots haven't changed in two decades. Most teams win by having more shots at goal (Wilcoxon-r effect size 0.63) than their opponent (i.e. "majority strategy") and of these, the number of open shots (0.48) is slightly more important than set shots (0.43), followed by shot accuracy (0.29). However, some teams (14 %) win by taking fewer shots at goal from field locations with a higher likelihood of scoring a goal (i.e. "minority strategy"). Arc angle and shot type can be used to predict the outcome of a shot at goal with 60.3 % classification accuracy. The novel shot-outcome prediction model reported here provides a better opportunity to evaluate goal kicking performance of teams and players, because it accounts for the type and difficulty of the shot. CONCLUSIONS: Teams can evaluate the shot accuracy of their players more fairly, by accounting for shot location using the method reported here. Coaches can compare the two shot strategies identified and implement the one that suits the skill profile of their players and increase their likelihood of winning.

Roof arc width: The novel calculation method for calculation of patient specific roof arc width in acetabular fractures.

PURPOSE: Roof arc angle (RAA) is determined by measuring angle between a vertical line drawn from center of the acetabulum towards the acetabular dome and a second line drawn from center of acetabulum to the fracture through the acetabulum. Joel and Matta demonstrated that when roof arc angle was less than 45° on Pelvic AP and Judet's views, the fracture line is considered to be passing through the weight-bearing dome and require surgical fixation. The main purpose of the study is to calculate patient-specific angle and width for the better evaluation and management of acetabular fractures. METHODS: Radiographs of normal hips were retrieved from electronic data and parameters were calculated. Two observers calculated the parameters at two different intervals. Pearson correlation formula was used to find a correlation between groups. RESULTS: Fifty radiographs of 28 patients were reviewed. The mean age of patients was 75.58 years ±13.28. The radius of the acetabulum, the radiographic measurement of sector width for 45° angulation at the roof, and the mathematical calculation for roof arc for 45° angle had significant positive correlation for both observers at two different occasions. CONCLUSIONS: The measured roof arc width ranges from a minimum of 16.20 mm-31.50 mm and the calculated arc width for a 45-degree angle varies from a minimum of 15 mm-25.56 mm. These values are higher than the described values of 10 mm equals to 45 degrees. Hence, the values measured in this study should be considered for decision making in the management of acetabular fractures.

Operative treatment of transverse acetabular fractures: is it really necessary to fix both columns?

OBJECTIVE: we prospectively evaluated clinical and radiographic outcomes in patients with displaced combined transverse-posterior wall acetabular fractures managed at our Institution over a period of seven years by posterolateral single approach, direct posterior wall and posterior column reduction and plating, and indirect reduction of anterior column controlled by fluoroscopic images with or without lag-screw fixation. The aim was to identify if the obtained immediate postoperative Matta radiographic roof-arc angles after fracture reduction and fixation alters in the postoperative period when comparing posterior plating alone versus posterior plate and anterior column lag-screw fixation. PATIENTS AND METHODS: 35 skeletally mature patients (31 male and four female, with mean age of 39.9 years old [range, 23.3 to 66.7 y/o]) with combined transverse-posterior wall acetabular fractures surgically treated by a posterolateral single approach were enrolled in this prospective investigation. Nineteen patients had associated orthopaedic injuries. The first part of the acetabular fracture management was similar to all patients and consisted in anatomical reduction and fixation of the transverse posterior component followed by anatomical reduction and fixation of the posterior wall component. The transverse anterior component reduction was controlled by fluoroscopic images (anteroposterior (AP), iliac oblique, and obturator oblique views) and digital palpation through the greater sciatic notch. Fifteen of the 35 patients had an additional lag-screw fixation from the posterior to the anterior columns with an extra-long small-fragment cortical screw. AP and Judet oblique radiographic views were taken at the end of the procedure and roof-arc angles were measured. Clinical results were assigned according to the grading system of Merle D'Aubigne and Postel as modified by Matta et al. Radiographic roof-arc angles were checked and compared between the two groups of patients to the same data collected both at the time of the surgical procedure and at three months postoperatively. Statistical analysis was done by either using chi-square (clinical outcome) and Mann-Whitney (roentgenographic outcome) tests, with a level of significance of alpha = 5%. RESULTS: at final follow-up examination 18 to 84 months postoperatively (mean, 46.8 months), the clinical results were considered satisfactory in 31 (88.6%) patients (excellent in nine (25.7%) and good in 22 (62.9%) patients). There was no difference between patients with (n = 15) and without (n = 20) fixation of the transverse anterior component of the acetabular fracture (p = 0.67). Radiographic roof-arc angles measured at discharge, at three months postoperatively and at the last follow-up consultation didn't changed significantly (p > 0.05). There was no statistically significant difference between patients treated with (n = 15) and without (n = 20) fixation of the anterior component of the transverse acetabular fracture in terms of medial displacement of the femoral head. CONCLUSION: the authors suggest that associated transverse-posterior wall acetabular fractures can be managed by a single posterior approach. Direct reduction and fixation of the posterior wall and column components is an adequate option for these injuries. If there is adequate indirect reduction of the anterior column, as checked by digital palpation and fluoroscopy, we feel that it is not necessary to fix the anterior column component of the transverse acetabular fracture.