Reconstruction of large cranial defects with poly-methyl-methacrylate (PMMA) using a rapid prototyping model and a new technique for intraoperative implant modeling

Background Reconstruction of large cranial defects after craniectomy can be accomplished by free-hand poly-methyl-methacrylate (PMMA) or industrially manufactured implants. The free-hand technique often does not achieve satisfactory cosmetic results but is inexpensive. In an attempt to combine the accuracy of specifically manufactured implants with low cost of PMMA. Methods Forty-six consecutive patients with large skull defects after trauma or infection were retrospectively analyzed. The defects were reconstructed using computer-aided design/computer-aided manufacturing (CAD/CAM) techniques. The computer file was imported into a rapid prototyping (RP) machine to produce an acrylonitrile-butadiene-styrene model (ABS) of the patient's bony head. The gas-sterilized model was used as a template for the intraoperative modeling of the PMMA cranioplasty. Thus, not the PMMA implant was generated by CAD/CAM technique but the model of the patients head to easily form a well-fitting implant. Cosmetic outcome was rated on a six-tiered scale by the patients after a minimum follow-up of three months. Results The mean size of the defect was 74.36cm2. The implants fitted well in all patients. Seven patients had a postoperative complication and underwent reoperation. Mean follow-up period was 41 months (range 2–91 months). Results were excellent in 42, good in three and not satisfactory in one patient. Costs per implant were approximately 550 Euros. Conclusion PMMA implants fabricated in-house by direct molding using a bio-model of the patients bony head are easily produced, fit properly and are inexpensive compared to cranial implants fabricated with other RP or milling techniques

Matching Lung Volume Data Sets – A Novel Approach

There is a significant demand in matching CT datasets of the lung. The increasing number of CT slices per examination due to the higher resolution of modern CT scanners and the need for quantification of the progress of disease and healing processes in follow-up studies. A volunteer’s lung was scanned by the means of multidetector CT in two different states of ventilation. The necessary lung structures for the matching procedure like lung surface and branching points were segmented. A thin-plate spline method was used to calculate the matched lung volume. The preliminary results show an average error of 2 voxel, i.e. 2mm. The calculation of the transformation matrix takes about one second on a conventional PC, which is considerably faster than other methods described in literature. The method described may be apt to be introduced in radiological practice when it comes to compare high resolution CT scans in follow-up studies quantitatively

A preliminary assessment of the thoracic remains of the El Sidrón Neandertals (Asturias, Spain)

Resumen del póster presentado en: 3rd Annual Meeting of the European Society for the study of Human Evolution, 19-21 September 2013, Vienna/AustriaPeer reviewe

Differential growth and development of the upper and lower human thorax

The difficulties in quantifying the 3D form and spatial relationships of the skeletal components of the ribcage present a barrier to studies of the growth of the thoracic skeleton. Thus, most studies to date have relied on traditional measurements such as distances and indices from single or few ribs. It is currently known that adult-like thoracic shape is achieved early, by the end of the second postnatal year, with the circular cross-section of the newborn thorax transforming into the ovoid shape of adults; and that the ribs become inclined such that their anterior borders come to lie inferior to their posterior. Here we present a study that revisits growth changes using geometric morphometrics applied to extensive landmark data taken from the ribcage. We digitized 402 (semi) landmarks on 3D reconstructions to assess growth changes in 27 computed tomography-scanned modern humans representing newborns to adults of both sexes. Our analyses show a curved ontogenetic trajectory, resulting from different ontogenetic growth allometries of upper and lower thoracic units. Adult thoracic morphology is achieved later than predicted, by diverse modifications in different anatomical regions during different ontogenetic stages. Besides a marked increase in antero-posterior dimensions, there is an increase in medio-lateral dimensions of the upper thorax, relative to the lower thorax. This transforms the pyramidal infant thorax into the barrel-shaped one of adults. Rib descent is produced by complex changes in 3D curvature. Developmental differences between upper and lower thoracic regions relate to differential timings and rates of maturation of the respiratory and digestive systems, the spine and the locomotor system. Our findings are relevant to understanding how changes in the relative rates of growth of these systems and structures impacted on the development and evolution of modern human body shapeCGL2012-37279 (Spanish Ministry for Economy and Competition) Fyssen-foundation (http://www.fondationfyssen.fr

Late subadult ontogeny and adult aging of the human thorax reveals divergent growth trajectories between sexes

Sexual dimorphism is an important feature of adult thorax morphology, but when and how sex-related differences in the ribcage arise during ontogeny is poorly known. Previous research proposed that sex-related size differences in the nasal region arise during puberty. Therefore, we explore whether ribcage sexual dimorphism also arises at that time and whether this sexual dimorphism is maintained until old age. We measured 526 (semi)landmarks on 80 CT-based human ribcage reconstructions, on individuals ranging from 7 to 65 year-old. The 3D coordinates were submitted to the Procrustes superimposition and analyzed. Our results show that the trajectories of thorax size and shape between sexes diverge at around 12 years of age, and continue slightly diverging until old age. The differential ontogenetic trends cause adult male ribcages to become deeper, shorter, and wider than female. Our results are consistent with the evidence from the cranial respiratory system, with the development of sexual dimorphism probably related to changes in body composition during puberty combined with changes in the reproductive system

ADC histograms predict response to anti-angiogenic therapy in patients with recurrent high-grade glioma.

INTRODUCTION The purpose of this study is to evaluate apparent diffusion coefficient (ADC) maps to distinguish anti-vascular and anti-tumor effects in the course of anti-angiogenic treatment of recurrent high-grade gliomas (rHGG) as compared to standard magnetic resonance imaging (MRI). METHODS This retrospective study analyzed ADC maps from diffusion-weighted MRI in 14 rHGG patients during bevacizumab/irinotecan (B/I) therapy. Applying image segmentation, volumes of contrast-enhanced lesions in T1 sequences and of hyperintense T2 lesions (hT2) were calculated. hT2 were defined as regions of interest (ROI) and registered to corresponding ADC maps (hT2-ADC). Histograms were calculated from hT2-ADC ROIs. Thereafter, histogram asymmetry termed "skewness" was calculated and compared to progression-free survival (PFS) as defined by the Response Assessment Neuro-Oncology (RANO) Working Group criteria. RESULTS At 8-12 weeks follow-up, seven (50%) patients showed a partial response, three (21.4%) patients were stable, and four (28.6%) patients progressed according to RANO criteria. hT2-ADC histograms demonstrated statistically significant changes in skewness in relation to PFS at 6 months. Patients with increasing skewness (n = 11) following B/I therapy had significantly shorter PFS than did patients with decreasing or stable skewness values (n = 3, median percentage change in skewness 54% versus -3%, p = 0.04). CONCLUSION In rHGG patients, the change in ADC histogram skewness may be predictive for treatment response early in the course of anti-angiogenic therapy and more sensitive than treatment assessment based solely on RANO criteria

3D-Scans und 3D-Drucke in der Musikarchäologie. Möglichkeiten und experimentalarchäologische Praxisbeispiele

3D-scans and 3D-printing in music archaeology. Possibilities and experimental archaeological practical examples. Due to new technologies, such as 3D-scanning and 3D-printing, revolutionary approaches have been made possible in the reconstruction of musical instruments found in archaeological sites. According to our tests, the method of 3D-scanning is safe, free of contamination, as well as interferences and does not affect the original material, provided that the original is made of suitable material and does not contain any metal parts. Whereas an ordinary documentation based on drawings and pictures does not always allow deeper understanding of the reconstruction of a fragmented instrument, the method of micro CT-scanning, if necessary digitally completing (based on pre-scanned samples) and 3D-printing allows the creation of an exact copy of the examined object, which is innumerably reproducible in order to experiment with different possibilities of the reconstruction. The exactness of these approaches has been successfully proven through frequency analysis on both the original and the 3D-printed clone. So the music of broken instruments can be brought back to life with comparatively little effort of time and money

Matching Lung Volume Data Sets – A Novel Approach

There is a significant demand in matching CT datasets of the lung. The increasing number of CT slices per examination due to the higher resolution of modern CT scanners and the need for quantification of the progress of disease and healing processes in follow-up studies. A volunteer’s lung was scanned by the means of multidetector CT in two different states of ventilation. The necessary lung structures for the matching procedure like lung surface and branching points were segmented. A thin-plate spline method was used to calculate the matched lung volume. The preliminary results show an average error of 2 voxel, i.e. 2mm. The calculation of the transformation matrix takes about one second on a conventional PC, which is considerably faster than other methods described in literature. The method described may be apt to be introduced in radiological practice when it comes to compare high resolution CT scans in follow-up studies quantitatively