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Post-TAVR persistent pulmonary hypertension (PH) is a better predictor of poor outcome than pre-TAVR PH. In this longitudinal study we sought to evaluate whether pulmonary artery (distensibility (D PA) measured on preprocedural ECG-gated CTA is associated with persistent-PH and 2-year mortality after TAVR. Three hundred and thirty-six patients undergoing TAVR between July 2012 and March 2016 were retrospectively included and followed for all-cause mortality until November 2017. All patients underwent retrospectively ECG-gated CTA prior to TAVR. Main pulmonary artery (MPA) area was measured in systole and in diastole. D PA was calculated as: [(area-MPA max –area-MPA min)/area-MPA max ]%. ROC analysis was performed to assess the AUC for persistent-PH. Youden Index was used to determine the optimal threshold of D PA for persistent-PH. Two groups were compared based on a D PA threshold of 8% (specificity of 70% for persistent-PH). Kaplan-Meier, Cox proportional-hazard, and logistic regression analyses were performed. The primary clinical endpoint was defined as persistent-PH post-TAVR. The secondary endpoint was defined as all-cause mortality 2 years after TAVR. Median follow-up time was 413 (interquartiles 339–757) days. A total of 183 (54%) had persistent-PH and 68 (20%) patients died within 2-years after TAVR. Patients with D PA <8% had significantly more persistent-PH (67% vs 47%, p <0.001) and 2-year deaths (28% vs 15%, p =0.006), compared to patients with D PA >8%. Adjusted multivariable regression analyses showed that D PA <8% was independently associated with persistent-PH (OR 2.10 [95%-CI 1.3–4.5], p =0.007) and 2-year mortality (HR 2.91 [95%-CI 1.5–5.8], p =0.002). Kaplan-Meier analysis showed that 2-year mortality of patients with D PA <8% was significantly higher compared to patients with D PA ≥8% (mortality 28% vs 15%; log-rank p =0.003). D PA on preprocedural CTA is independently associated with persistent-PH and two-year mortality in patients who undergo TAVR. [ABSTRACT FROM AUTHOR]

Identifying high-risk patients who will not derive substantial survival benefit from TAVR remains challenging. Pulmonary hypertension is a known predictor of poor outcome in patients undergoing TAVR and correlates strongly with pulmonary artery (PA) enlargement on CTA. We sought to evaluate whether PA enlargement, measured on pre-procedural computed tomography angiography (CTA), is associated with 1-year mortality in patients undergoing TAVR. We retrospectively included 402 patients undergoing TAVR between July 2012 and March 2016. Clinical parameters, including Society of Thoracic Surgeons (STS) score and right ventricular systolic pressure (RVSP) estimated by transthoracic echocardiography were reviewed. PA dimensions were measured on pre-procedural CTAs. Association between PA enlargement and 1-year mortality was analyzed. Kaplan-Meier and Cox proportional hazards regression analyses were performed. The median follow-up time was 433 (interquartiles 339–797) days. A total of 56/402 (14%) patients died within 1 year after TAVR. Main PA area (area-MPA) was independently associated with 1-year mortality (hazard ratio per standard deviation equal to 2.04 [95%-confidence interval (CI) 1.48–2.76], p ​< ​0.001). Area under the curve (95%-CI) of the clinical multivariable model including STS-score and RVSP increased slightly from 0.67 (0.59–0.75) to 0.72 (0.72–0.89), p ​= ​0.346 by adding area-MPA. Although the AUC increased, differences were not significant (p ​= ​0.346). Kaplan-Meier analysis showed that mortality was significantly higher in patients with a pre-procedural non-indexed area-MPA of ≥7.40 ​cm2 compared to patients with a smaller area-MPA (mortality 23% vs. 9%; p ​< ​0.001). Enlargement of MPA on pre-procedural CTA is independently associated with 1-year mortality after TAVR. TAVR is highly effective at reducing mortality of patients with severe aortic stenosis. However, despite the high rates of procedural success, some patients do not achieve a functional benefit or die within a short time period after the procedure. Pulmonary hypertension is a known predictor of poor outcome in patients undergoing TAVR and correlates strongly with PA enlargement measured on CT. Our study shows that MPA enlargement, defined as area-MPA ≥7.40 ​cm2 on pre-procedural CTA, is an independent predictor of 1-year mortality after TAVR. This imaging marker could be relevant in improving individual risk classification in TAVR candidates. [ABSTRACT FROM AUTHOR]

• Strategies how to develop AI applications as clinical decision support systems are provided. • We focus on differences between radiomic machine learning and deep learning application domains. • Pros and cons, recommendations and references to software tools are provided. Artificial intelligence (AI) models are playing an increasing role in biomedical research and healthcare services. This review focuses on challenges points to be clarified about how to develop AI applications as clinical decision support systems in the real-world context. A narrative review has been performed including a critical assessment of articles published between 1989 and 2021 that guided challenging sections. We first illustrate the architectural characteristics of machine learning (ML)/radiomics and deep learning (DL) approaches. For ML/radiomics, the phases of feature selection and of training, validation, and testing are described. DL models are presented as multi-layered artificial/convolutional neural networks, allowing us to directly process images. The data curation section includes technical steps such as image labelling, image annotation (with segmentation as a crucial step in radiomics), data harmonization (enabling compensation for differences in imaging protocols that typically generate noise in non-AI imaging studies) and federated learning. Thereafter, we dedicate specific sections to: sample size calculation, considering multiple testing in AI approaches; procedures for data augmentation to work with limited and unbalanced datasets; and the interpretability of AI models (the so-called black box issue). Pros and cons for choosing ML versus DL to implement AI applications to medical imaging are finally presented in a synoptic way. Biomedicine and healthcare systems are one of the most important fields for AI applications and medical imaging is probably the most suitable and promising domain. Clarification of specific challenging points facilitates the development of such systems and their translation to clinical practice. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to quantitatively assess the performance of metal artifact reduction (MAR) algorithms on the volume of metal cylinders, considering the influence of materials, positions, and fields of view (FOVs), by using 3 cone beam computed tomography (CBCT) devices (NewTom VGi evo, Picasso Trio, and ProMax 3-D Max).Study Design: Nine phantoms containing cylinders of amalgam, copper-aluminum (CuAl) metal alloy, and titanium, combined in up to 3 positions, were scanned by using 2 different FOVs. MATLAB software was used to evaluate the differences between volumes before and after MAR application, and the possible interference of materials, positions, and FOVs. Wilcoxon's test and the Kruskal-Wallis test were used at a level of significance of 5%.Results: In general, images containing amalgam and CuAl showed a significant difference in volume before and after MAR application. However, no significant difference after MAR was observed (P > .05) relative to positions and FOVs. MAR had an impact on the cylinder volumes only in the NewTom VGi evo and ProMax 3-D Max scanners.Conclusions: The performance of MAR algorithms in volume correction of metal objects is dependent on the materials and the CBCT unit. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to assess the performance of 2 metal artifact reduction (MAR) algorithms in cone beam computed tomography (CBCT) imaging, considering different materials, metal positions, and fields of view (FOVs).Study Design: Nine phantoms containing cylinders of amalgam, copper-aluminum (Cu-Al) alloy, and titanium were scanned by using Picasso Trio and ProMax 3D CBCT units with small and medium FOVs. Scans were made with and without MAR algorithms. The standard deviation (SD) of voxel gray values was measured in the neighborhood of the cylinders. Differences in SD were statistically evaluated for effects of MAR and the other parameters, with a significance level of 5%.Results: Significant differences between images with MAR and those without MAR for both devices (P ≤ .0001) were observed. Amalgam showed the largest artifact expression, followed by Cu-Al and titanium. After correction, differences remained only in Picasso Trio images (P = .002). Considering positions, no significant difference in the performance of the MAR algorithm was observed in either device. Considering FOVs, significant differences were observed for ProMax 3D (P = .005), with less artifact expression in the medium FOV after MAR correction.Conclusions: MAR algorithms were effective for artifact reduction despite variation in performance according to device, FOV, and material properties. The position of the metal cylinder within the FOV had no significant effect. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to perform a longitudinal morphometric analysis of the alterations of the maxillary dental arches in children with cleft lip and palate before and after primary lip and/or palate surgeries using a 3-dimensional stereophotogrammetry system.Study Design: The sample consisted of dental casts of 60 children with complete unilateral cleft lip (UCL) and complete unilateral cleft lip and palate (UCLP). Dental arches were evaluated before cheiloplasty (T1), after cheiloplasty (T2), and 1 year after palatoplasty (T3). Independent t test and Mann-Whitney U test were used for intergroup comparisons, and paired t test, Wilcoxon's test, and repeated-measures analysis of variance (ANOVA), followed by Tukey's test, were used for intragroup comparisons.Results: At T1, the intercanine and intertuberosity distances in the UCLP group were statistically greater than those in the UCL group. At T2, the maxillary dimensions significantly increased, except for the intertuberosity distance in UCL. Between T1 and T3, the intercanine distance and the anterior length decreased significantly, whereas the intertuberosity distance and the total length of the palate increased significantly.Conclusions: Our results indicated that the primary lip surgery altered the development of dental arches, evidently in children with UCLP. The primary palate surgery interfered in the growth of the anterior palatal region in the UCLP group. Children with UCLP had more restricted development of the maxillary dental arch compared with children with UCL. [ABSTRACT FROM AUTHOR]

Purpose: The quantitative assessment of facial modifications from mimicry is of relevant interest for the rehabilitation of patients who can no longer produce facial expressions. This study investigated a novel application of 3-dimensional on 3-dimensional superimposition for facial mimicry.Materials and Methods: This cross-sectional study was based on 10 men 30 to 40 years old who underwent stereophotogrammetry for neutral, happy, sad, and angry expressions. Registration of facial expressions on the neutral expression was performed. Root mean square (RMS) point-to-point distance in the labial area was calculated between each facial expression and the neutral one and was considered the main parameter for assessing facial modifications. In addition, effect size (Cohen d) was calculated to assess the effects of labial movements in relation to facial modifications.Results: All participants were free from possible facial deformities, pathologies, or trauma that could affect facial mimicry. RMS values of facial areas differed significantly among facial expressions (P = .0004 by Friedman test). The widest modifications of the lips were observed in happy expressions (RMS, 4.06 mm; standard deviation [SD], 1.14 mm), with a statistically relevant difference compared with the sad (RMS, 1.42 mm; SD, 1.15 mm) and angry (RMS, 0.76 mm; SD, 0.45 mm) expressions. The effect size of labial versus total face movements was limited for happy and sad expressions and large for the angry expression.Conclusion: This study found that a happy expression provides wider modifications of the lips than the other facial expressions and suggests a novel procedure for assessing regional changes from mimicry. [ABSTRACT FROM AUTHOR]

Purpose In this study we proposed a fully automated method for localizing and segmenting the ascending aortic lumen with phase-contrast magnetic resonance imaging (PC-MRI). Material and methods Twenty-five phase-contrast series were randomly selected out of a large population dataset of patients whose cardiac MRI examination, performed from September 2008 to October 2013, was unremarkable. The local Ethical Committee approved this retrospective study. The ascending aorta was automatically identified on each phase of the cardiac cycle using a priori knowledge of aortic geometry. The frame that maximized the area, eccentricity, and solidity parameters was chosen for unsupervised initialization. Aortic segmentation was performed on each frame using active contouring without edges techniques. The entire algorithm was developed using Matlab R2016b. To validate the proposed method, the manual segmentation performed by a highly experienced operator was used. Dice similarity coefficient, Bland-Altman analysis, and Pearson's correlation coefficient were used as performance metrics. Results Comparing automated and manual segmentation of the aortic lumen on 714 images, Bland-Altman analysis showed a bias of − 6.68 mm 2 , a coefficient of repeatability of 91.22 mm 2 , a mean area measurement of 581.40 mm 2 , and a reproducibility of 85%. Automated and manual segmentation were highly correlated ( R = 0.98). The Dice similarity coefficient versus the manual reference standard was 94.6 ± 2.1% (mean ± standard deviation). Conclusion A fully automated and robust method for identification and segmentation of ascending aorta on PC-MRI was developed. Its application on patients with a variety of pathologic conditions is advisable. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate ascending aortic strain (AAS) with cardiac magnetic resonance (CMR) in a large consecutive series of patients with different types of cardiovascular disease (CVD).Methods: Two-dimensional phase-contrast gradient-echo sequences of the ascending aorta were retrospectively reviewed in 1027 patients (726 males, 301 females). Aortic lumen area was segmented using a semi-automatic approach to calculate AAS values. Subgroup analysis was performed for patients with normal CMR, tetralogy of Fallot (ToF), and ischemic heart disease (IHD). Multivariate and post-hoc analyses were performed to evaluate the effect of age, gender, and CVD on AAS values. Shapiro-Wilk, three- and two-way ANOVA, Mann-Whitney U, and Spearman correlation statistics were used.Results: Multivariate analysis showed significant differences in AAS among decades of age (p<0.001), genders (p=0.006) and CVD subgroups (p<0.001) without interaction among these factors. A gender-related difference (higher AAS in females) was significant in ToF (p=0.008), while an AAS reduction during aging was observed in all CVD subgroups. Post-hoc analysis showed a significantly lower AAS in ToF and IHD patients compared to subjects with normal CMR (p<0.001).Conclusion: Differences in age, gender, and CVD independently affect AAS. The lower AAS observed in ToF fosters its assessment during follow-up in adulthood. Future studies on causes and clinical implications of a higher AAS in females affected by ToF are warranted. [ABSTRACT FROM AUTHOR]

Introduction Tooth autotransplantation (TAT) offers a viable biological approach to tooth replacement in children. To enhance the outcome predictability of the TAT procedure, a cone-beam computed tomographic (CBCT)-based surgical planning and transfer technique has been developed. The aim of this study was to optimize the CBCT scanning protocol to achieve a dose as low as possible and to maintain sufficient image quality. Methods A sectional head phantom (SK150; The Phantom Laboratory, Salem, NY) was scanned using 18 exposure protocols in 3 different CBCT machines: 3D Accuitomo 170 (Morita, Kyoto, Japan), ProMax 3D MAX (Planmeca, Helsinki, Finland), and NewTom VGI EVO (QR Verona, Verona, Italy). The effective dose (ED) was calculated using Monte Carlo simulation and pediatric voxel phantoms (5- and 8-year-old males and a 12-year-old female). Image quality was assessed by comparing segmented teeth volumes, evaluation of the visibility of the lamina dura, and morphologic surface analysis of 3-dimensional models. A general linear mixed model was fit to combine image quality parameters and radiation effective dose for each protocol in order to rank and compare the protocols examined in the study. Results The ED for the preoperative scan can be reduced to the range of 74.6–157.9 μSv, with ProMax with ultra–low-dose high-definition reconstruction (Planmeca) 100 × 90 scoring the highest. The ED for the postoperative scan can be reduced to the range of 24.2–41.5 μSv with ProMax with ultra–low-dose normal-dose reconstruction 50 × 55 and NewTom 50 × 50 with the standard mode scoring the highest. Conclusions A considerable reduction in the pediatric ED can be achieved while maintaining sufficient image quality for tooth autotransplantation planning and follow-up using the dose optimization protocols. [ABSTRACT FROM AUTHOR]

Many conditions can compromise facial symmetry, resulting in an impairment of the affected person from both esthetic and functional points of view. For these reasons, a detailed, focused, and objective evaluation of facial asymmetry is needed, both for surgical planning and for treatment evaluation. In this study, we present a new quantitative method to assess symmetry in different facial thirds, objectively defined on the territories of distribution of trigeminal branches. A total of 70 subjects (40 healthy controls and 30 patients with unilateral facial palsy) participated. A stereophotogrammetric system and the level of asymmetry of the subjects' hemi-facial thirds was evaluated, comparing the root mean square of the distances (RMSD) between their original and mirrored facial surfaces. Results show a high average reproducibility of area selection (98.8%) and significant differences in RMSD values between controls and patients (p = 0.000) for all of the facial thirds. No significant differences were found on different thirds among controls (p > 0.05), whereas significant differences were found for the upper, middle, and lower thirds of patients (p = 0.000). The presented method provides an accurate, reproducible, and local facial symmetry analysis that can be used for different conditions, especially when only part of the face is asymmetric. [ABSTRACT FROM AUTHOR]

Information about age-related and sex-related normative measurements of the nasolabial region in native Northern Sudanese subjects is scanty. We have therefore used a hand-held laser scanner to measure nasolabial angles and distances, and collected the 3-dimensional coordinates of seven landmarks on the facial soft tissues from 654 healthy native Northern Sudanese subjects (327 male and 327 female, aged 4-30 years). From these we calculated five angles and two linear distances and took the mean (SD) for age and sex, and compared them using factorial analysis of variance. All measurements analysed were significantly modified by age in both sexes (p < 0.01 ) except for the distance from the lower lip to Ricketts’ E-line. Sex had a significant effect on the mentolabial and maxillary prominence angles and both distances ( p < 0.005 ). Nasal convexity and the interlabial angle became more obtuse with growth, while the nasolabial and mentolabial angles reduced progressively with female subjects having significantly more obtuse mentolabial angles (p < 0.001 ). The maxillary prominence angle progressively decreased during childhood, and increased after adolescence, with larger values in male subjects. The upper and lower lip distances from Ricketts’ E-line were also significantly larger in male subjects (p < 0.003 ), but the difference reduced with age. Overall, there were several differences when we compared our data with published data for African and white subjects, which points to the need for ethnic-specific data. Measurements collected in the current study could be used for the quantitative description of facial morphology in native Northern Sudanese children, adolescents, and young adults. [ABSTRACT FROM AUTHOR]

We wanted to find and validate a new way to visualise patients’ faces and their dental arches non-invasively. The stereophotogrammetric images of the faces and the digitised dental casts of seven healthy subjects were analysed. Point-based and surface-based recording techniques matched the facial image with those of the mandibular and maxillary dental arches in their relative positions. The cone-beam computed tomographic (CT) images of the same subjects were analysed retrospectively. Twenty-eight dentofacial distances were obtained on cone-beam CT images and on the recorded facial and dental surfaces. The median (IQR) distances of more than 96% of the measurements did not differ significantly. [ABSTRACT FROM AUTHOR]

Purpose: To highlight the importance of quantitative breast arterial calcifications (BAC) assessment for an effective stratification of cardiovascular (CV) risk in women, for whom current preventive strategies are inadequate. BAC, easily detectable on mammograms, are associated with CV disease and represent a potential imaging biomarker for CV disease prevention in women.Method: We summarized the available evidence on this topic.Results: Age, parity, diabetes, and hyperlipidemia were found to positively correlate with BAC. Women with BAC have a higher CV risk than those without BAC: the relative risk was reported to be 1.4 for transient ischemic attack/stroke, 1.5 for thrombosis, 1.8 for myocardial infarction; the reported hazard ratio was 1.32 for coronary artery disease (CAD), 1.52 for heart failure, 1.29 for CV death, 1.44 for death from CAD. However, BAC do not alarm radiologists; when reported, they are commonly mentioned as "present", not impacting on CV decision-making. Of 18 published studies, 9 reported only presence/absence of BAC, 4 used a semi-quantitative scale, and 5 a continuous scale (with manual, automatic or semiautomatic segmentation). Various appearance, topological complexity, and vessels overlap make BAC quantification difficult to standardize. Nevertheless, machine learning approaches showed promising results in BAC quantification on mammograms.Conclusions: There is a strong rationale for mammography to become a dual test for breast cancer screening and CV disease prevention. However, robust and automated quantification methods are needed for a deeper insight on the association between BAC and CV disease, to stratifying CV risk and define personalized preventive actions. [ABSTRACT FROM AUTHOR]