Three-dimensional facial volume analysis using algorithm-based personalized aesthetic templates

Three-dimensional stereophotogrammetry is commonly used to assess volumetric changes after facial procedures. A lack of clear landmarks in aesthetic regions complicates the reproduction of selected areas in sequential images. A three-dimensional volumetric analysis was developed based on a personalized aesthetic template. The accuracy and reproducibility of this method were assessed. Six female volunteers were photographed using the 3dMDtrio system according to a clinical protocol, twice at baseline (T1) and twice after 1 year (T2). A styrofoam head was used as control. A standardized aesthetic template was morphed over the baseline images of the volunteers using a coherent point drift algorithm. The resulting personalized template was projected over all sequential images to assess surface area differences, volume differences, and root mean square errors. In 12 well-defined aesthetic areas, mean average surface area and volume differences between the two T1 images ranged from -7.6 mm(2) to 10.1 mm(2) and -0.11 cm(3) to 0.13 cm(3) , respectively. T1 root mean square errors ranged between 0.24 mm and 0.62 mm (standard deviation 0.18-0.73 mm). Comparable differences were found between the T2 images. An increase in volume between T1 and T2 was only observed for volunteers who gained in body weight. Personalized aesthetic templates are an accurate and reproducible method to assess changes in aesthetic areas

Comparing the influence of mixed reality, a 3D viewer, and MRI on the spatial understanding of brain tumours

Background: Multiple 3D visualization techniques are available that obviates the need for the surgeon to mentally transform the 2D planes from MRI to the 3D anatomy of the patient. We assessed the spatial understanding of a brain tumour when visualized with MRI, 3D models on a monitor or 3D models in mixed reality.Methods: Medical students, neurosurgical residents and neurosurgeons were divided into three groups based on the imaging modality used for preparation: MRI, 3D viewer and mixed reality. After preparation, the participants needed to position, scale, and rotate a virtual tumour inside a virtual head of the patient in the same orientation as the original tumour would be. Primary outcome was the amount of overlap between the placed tumour and the original tumour to evaluate accuracy. Secondary outcomes were the position, volume and rotation deviation compared to the original tumour.Results: A total of 12 medical students, 12 neurosurgical residents, and 12 neurosurgeons were included. For medical students, the mean amount of overlap for the MRI, 3D viewer and mixed reality group was 0.26 (0.22), 0.38 (0.20) and 0.48 (0.20) respectively. For residents 0.45 (0.23), 0.45 (0.19) and 0.68 (0.11) and for neurosurgeons 0.39 (0.20), 0.50 (0.27) and 0.67 (0.14). The amount of overlap for mixed reality was significantly higher on all expertise levels compared to MRI and on resident and neurosurgeon level also compared to the 3D viewer. Furthermore, mixed reality showed the lowest deviations in position, volume and rotation on all expertise levels.Conclusion: Mixed reality enhances the spatial understanding of brain tumours compared to MRI and 3D models on a monitor. The preoperative use of mixed reality may therefore support the surgeon to improve spatial 3D related surgical tasks such as patient positioning and planning surgical trajectories

A novel seven-octapeptide repeat insertion in the prion protein gene (PRNP) in a Dutch pedigree with Gerstmann–Sträussler–Scheinker disease phenotype: comparison with similar cases from the literature

Human prion diseases can be sporadic, inherited or acquired by infection and show considerable phenotypic heterogeneity. We describe the clinical, histopathological and pathological prion protein (PrPSc) characteristics of a Dutch family with a novel 7-octapeptide repeat insertion (7-OPRI) in PRNP, the gene encoding the prion protein (PrP). Clinical features were available in four, neuropathological features in three and biochemical characteristics in two members of this family. The clinical phenotype was characterized by slowly progressive cognitive decline, personality change, lethargy, depression with anxiety and panic attacks, apraxia and a hypokinetic-rigid syndrome. Neuropathological findings consisted of numerous multi- and unicentric amyloid plaques throughout the cerebrum and cerebellum with varying degrees of spongiform degeneration. Genetic and molecular studies were performed in two male family members. One of them was homozygous for valine and the other heterozygous for methionine and valine at codon 129 of PRNP. Sequence analysis identified a novel 168 bp insertion [R2–R2–R2–R2–R3g–R2–R2] in the octapeptide repeat region of PRNP. Both patients carried the mutation on the allele with valine at codon 129. Western blot analysis showed type 1 PrPSc in both patients and detected a smaller ~8 kDa PrPSc fragment in the cerebellum in one patient. The features of this Dutch kindred define an unusual neuropathological phenotype and a novel PRNP haplotype among the previously documented 7-OPRI mutations, further expanding the spectrum of genotype–phenotype correlations in inherited prion diseases

Flumazenil therapy for hepatic encephalopathy. A double-blind cross over study

Objectives and methods. Thirty-one patients with acute or chronic liver disease were included in the study to investigate the effect of flumazenil on hepatic encephalopathy. After screening for recent benzodiazepine use or non-hepatic causes of encephalopathy, 18 patients entered a double-blind cross-over study. The 13 remaining patients, most of them with renal failure or recent use of benzodiazepines, were given flumazenil in an open study. In the controlled study, flumazenil (1.0 mg) or placebo was given in a single injection on two separate days to study the immediate effect; half the patients received a continuous infusion of flumazenil (0.25 mg/h) or placebo for two 3-day periods to study a potential steady state effect. In the open study, a single bolus of flumazenil (1.0 mg) was given. Results. In the controlled study, fifteen minutes after bolus injection, the clinical grade of hepatic encephalopathy decreased in 6 patients after injection of flumazenil, whereas a decrease was found in 2 after the placebo (P = 0.06). However, the EEG grade did not change in any of the patients, and the changes in the mean dominant frequency as measured by spectral analysis did not differ between flumazenil and the placebo. Furthermore, patients on flumazenil did not differ significantly from those on placebo during the infusion period. Subgroup analysis of underlying liver disease and the causes of encephalopathy revealed a trend for clinical improvement only in the patients with chronic liver disease, but without significant changes in the mean dominant frequency. In the open study, the clinical grade of encephalopathy decreased in 3 patients and, in contrast to the controlled study, the EEG also improved in 2 patients and the mean dominant frequency increased significantly. Responders had previously used benzodiazepines. Conclusion. Our study does not support a major therapeutic effect of flumazenil on hepatic encephalopathy.</p

Nasolabial shape and aesthetics in unilateral cleft lip and palate: an analysis of nasolabial shape using a mean 3D facial template.

The aim of this study was to determine the amount of deviation in nasolabial shape in patients with a cleft compared with an average non-cleft face, and to assess whether this difference is related to nasolabial aesthetics. Three-dimensional stereophotogrammetric images of 60 patients with a unilateral cleft were used. To quantify shape differences, four average non-cleft faces were constructed from stereophotogrammetric images of 141 girls and 60 boys. Three-dimensional shape differences were calculated between superimposed cleft faces and the average non-cleft face for the same sex and age group. Nasolabial aesthetics were rated with the modified Asher-McDade Aesthetic Index using a visual analogue scale (VAS). Mean VAS scores ranged from 51.44 to 60.21 for clefts, with lower aesthetic ratings associated with increasing cleft severity. Shape differences were found between cleft faces and the average non-cleft face. No relationship was found for the VAS, age, and sex, except that a lower VAS was related to a higher nose and lip distance between the superimposed cleft and average non-cleft faces for nasal profile (P= 0.02), but the explained variance was low (R2=0.066). In conclusion, except for nasal profile, nasolabial aesthetics were not influenced by the extent of shape differences from the average non-cleft face

Flumazenil therapy for hepatic encephalopathy. A double-blind cross over study

Objectives and methods. Thirty-one patients with acute or chronic liver disease were included in the study to investigate the effect of flumazenil on hepatic encephalopathy. After screening for recent benzodiazepine use or non-hepatic causes of encephalopathy, 18 patients entered a double-blind cross-over study. The 13 remaining patients, most of them with renal failure or recent use of benzodiazepines, were given flumazenil in an open study. In the controlled study, flumazenil (1.0 mg) or placebo was given in a single injection on two separate days to study the immediate effect; half the patients received a continuous infusion of flumazenil (0.25 mg/h) or placebo for two 3-day periods to study a potential steady state effect. In the open study, a single bolus of flumazenil (1.0 mg) was given. Results. In the controlled study, fifteen minutes after bolus injection, the clinical grade of hepatic encephalopathy decreased in 6 patients after injection of flumazenil, whereas a decrease was found in 2 after the placebo (P = 0.06). However, the EEG grade did not change in any of the patients, and the changes in the mean dominant frequency as measured by spectral analysis did not differ between flumazenil and the placebo. Furthermore, patients on flumazenil did not differ significantly from those on placebo during the infusion period. Subgroup analysis of underlying liver disease and the causes of encephalopathy revealed a trend for clinical improvement only in the patients with chronic liver disease, but without significant changes in the mean dominant frequency. In the open study, the clinical grade of encephalopathy decreased in 3 patients and, in contrast to the controlled study, the EEG also improved in 2 patients and the mean dominant frequency increased significantly. Responders had previously used benzodiazepines. Conclusion. Our study does not support a major therapeutic effect of flumazenil on hepatic encephalopathy.</p

Holographic Augmented Reality for DIEP Flap Harvest

Background: During a deep inferior epigastric perforator (DIEP) flap harvest, the identification and localization of the epigastric arteries and its perforators are crucial. Holographic augmented reality is an innovative technique that can be used to visualize this patient-specific anatomy extracted from a computed tomographic scan directly on the patient. This study describes an innovative workflow to achieve this. Methods: A software application for the Microsoft HoloLens was developed to visualize the anatomy as a hologram. By using abdominal nevi as natural landmarks, the anatomy hologram is registered to the patient. To ensure that the anatomy hologram remains correctly positioned when the patient or the user moves, real-time patient tracking is obtained with a quick response marker attached to the patient. Results: Holographic augmented reality can be used to visualize the epigastric arteries and its perforators in preparation for a deep inferior epigastric perforator flap harvest. Conclusions: Potentially, this workflow can be used visualize the vessels intraoperatively. Furthermore, this workflow is intuitive to use and could be applied for other flaps or other types of surgery

The normal evolution of the cranium in three dimensions.

Insight into the growth and development of the normal newborn cranial shape is essential to monitor cranial development, to detect and diagnose abnormal skull shapes, and for the long-term follow-up of craniosynostosis surgery. The aim of this study was to analyse the growth pattern of the cranial shape of infants during the first years of life using 3D stereophotogrammetry and 3D computed tomography (CT) with advanced 3D evaluation techniques. A large set of 3D photographs (n=199) and CT scans (n=183), taken between ages 0 and 54 months, was collected. Cranial shapes with artefacts and asymmetries were removed. Total volumes and intracranial volumes were obtained, as well as 3D and 2D measurements, including the cranial width, cranial length, cranial index, and suture lengths. Growth maps were created for all modalities to indicate 3D growth over time. For the final analysis, a total of 130 3D photographs, 94 hard tissue CT scans, and 76 soft tissue CT scans were used. 3D and 2D measures, volumes, growth maps, and growth animations were obtained. A non-uniform growth was revealed by the 3D growth maps. This study addresses the need for normative cranial evolution data to monitor healthy cranial development and for detection, follow-up, and treatment planning in craniosynostosis

Toward Holographic-Guided Surgery

The implementation of augmented reality (AR) in image-guided surgery (IGS) can improve surgical interventions by presenting the image data directly on the patient at the correct position and in the actual orientation. This approach can resolve the switching focus problem, which occurs in conventional IGS systems when the surgeon has to look away from the operation field to consult the image data on a 2-dimensional screen. The Microsoft HoloLens, a head-mounted AR display, was combined with an optical navigation system to create an AR-based IGS system. Experiments were performed on a phantom model to determine the accuracy of the complete system and to evaluate the effect of adding AR. The results demonstrated a mean Euclidean distance of 2.3 mm with a maximum error of 3.5 mm for the complete system. Adding AR visualization to a conventional system increased the mean error by 1.6 mm. The introduction of AR in IGS was promising. The presented system provided a solution for the switching focus problem and created a more intuitive guidance system. With a further reduction in the error and more research to optimize the visualization, many surgical applications could benefit from the advantages of AR guidance