Extended Reality (XR) technologies have opened new possibilities for image visualization in healthcare, but eliciting user requirements for XR development is challenging. Human-computer interaction can help obtain User Mental Models, mostly unexplored in XR for health. An ongoing project aims to address this gap by studying the skills and backgrounds of radiologists and surgeons using the same XR tool in Preoperative Surgical Planning for Complex Malformations through elucidating mental model, performing technical review and proposing Potential Interaction Models or Interaction Concepts. The work aims to contribute insights for designing more intuitive, immersive medical visualization tools.

Spatial compression is a crucial skill for a mathematical or engineering student and anyone working with 3D surfaces. Consequently, a well-known issue in math education is that individuals who do not attain a suitable level of spatial compression may encounter difficulties when dealing with more advanced topics. To address this, 3D surface isolines generation is an effective task for honing spatial compression skills. Immersive visualization presents potential alternatives to facilitate the acquisition of spatial compression. This work introduces a 3D interaction flow designed to cut, visualize, and comprehend isolines of 3D surfaces. The proposed technique provides gesture interaction to carry out the task of manipulating 3D surfaces, defining cut planes, and manipulating slices. This proposal offers the option of defining non-canonical project planes to take advantage of the benefits of immersive visualization.

Background Superior mesenteric artery plexus (SMAP) injury is reported to cause postoperative intractable diarrhea after pancreatic/colonic surgery with extended lymphadenectomy. This study aims to describe the SMAP microanatomy and extent of injury after right colectomy with extended D3 mesenterectomy for cancer. Methods Three groups (I) anatomical dissection, (II) postmortem histology, and (III) surgical specimen histology were included. Nerve count and area were compared between groups II and III and paravascular sheath thickness between groups I and II. 3D models were generated through 3D histology, nanoCT scanning, and finally through 3D printing. Results A total of 21 specimens were included as follows: Group (I): 5 (3 females, 80–93 years), the SMAP is a complex mesh surrounding the superior mesenteric artery (SMA), branching out, following peripheral arteries and intertwining between them, (II): 7 (5 females, 71–86 years), nerve count: 53 ± 12.42 (38–68), and area: 1.84 ± 0.50 mm 2 (1.16–2.29), and (III): 9 (5 females, 55–69 years), nerve count: 31.6 ± 6.74 (range 23–43), and area: 0.889 ± 0.45 mm 2 (range 0.479–1.668). SMAP transection injury is 59% of nerve count and 48% of nerve area at middle colic artery origin level. The median values of paravascular sheath thickness decreased caudally from 2.05 to 1.04 mm (anatomical dissection) and from 2.65 to 1.17 mm (postmortem histology). 3D histology models present nerve fibers exclusively within the paravascular sheath, and lymph nodes were observed only outside. NanoCT-derived models reveal oblique nerve fiber trajectories with inclinations between 35° and 55°. Two 3D-printed models of the SMAP were also achieved in a 1:2 scale. Conclusion SMAP surrounds the SMA and branches within the paravascular sheath, while bowel lymph nodes and vessels lie outside. Extent of SMAP injury on histological slides (transection only) was 48% nerve area and 59% nerve count. The 35°–55° inclination range of SMAP nerves possibly imply an even larger injury when plexus excision is performed (lymphadenectomy). Reasons for later improvement of bowel function in these patients can lie in the interarterial nerve fibers between SMA branches.

New methods for holographic visualisation provide a true three-dimensional experience of medical images. The technique is generating great interest among surgeons.

BackgroundThree-dimensional (3D) printing technology has recently been well approved as an emerging technology in various fields of medical education and practice; e.g., there are numerous studies evaluating 3D printouts of solid organs. Complex surgery such as extended mesenterectomy imposes a need to analyze also the accuracy of 3D printouts of more mobile and complex structures like the diversity of vascular arborization within the central mesentery. The objective of this study was to evaluate the linear dimensional anatomy landmark differences of the superior mesenteric artery and vein between (1) 3D virtual models, (2) 3D printouts, and (3) peroperative measurements.MethodsThe study included 22 patients from the ongoing prospective multicenter trial Safe Radical D3 Right Hemicolectomy for Cancer through Preoperative Biphasic MDCT Angiography, with preoperative CT and peroperative measurements. The patients were operated in Norway between January 2016 and 2017. Their CT datasets underwent 3D volume rendering andsegmentation, and the virtual 3D model produced was then exported for stereolithography 3D printing.ResultsFour parameters were measured: distance between the origins of the ileocolic and the middle colic artery, distance between the termination of the gastrocolic trunk and the ileocolic vein, and the calibers of the middle colic and ileocolic arteries. The inter-arterial distance has proven a strong correlation between all the three modalities implied (Pearson's coefficient 0.968, 0.956, 0.779, respectively), while inter-venous distances showed a weak correlation between peroperative measurements and both virtual and physical models.ConclusionThis study showed acceptable dimensional inter-arterial correlations between 3D printed models, 3D virtual models and authentic soft tissue anatomy of the central mesenteric vessels, and weaker inter-venous correlations between all the models, reflecting the highly variable nature of veins in situ.

OBJECTIVE Type 2 deiodinase gene (DIO2) polymorphisms have been associated with changes in pituitary-thyroid axis homeostasis. The -258A/G (SNP rs12885300) polymorphism has been associated with increased enzymatic activity, but data are conflicting. To characterize the effects of -258A/G polymorphism on intrathyroidal thyroxine (T(4)) to triiodothyronine (T(3)) conversion and thyroid hormone (TH) secretion pattern, we studied the effects of acute, TRH-mediated, TSH stimulation of the thyroid gland. DESIGN Retrospective analysis. METHODS The TH secretion in response to 500  μg i.v. TRH injection was studied in 45 healthy volunteers. RESULTS Twenty-six subjects (16 females and ten males, 32.8 ± 10.4 years) were homozygous for the ancestral (-258A/A) allele and 19 (11 females and eight males, 31.1 ± 10.9 years) were carriers of the (-258G/x) variant. While no differences in the peak TSH and T(3) levels were observed, carriers of the -258G/x allele showed a blunted rise in free T(4) (FT(4); P<0.01). The -258G/x92Thr/Thr haplotype, compared with the other groups, had lower TSH values at 60  min (P<0.03). No differences were observed between genotypes in baseline TH levels. CONCLUSIONS The -258G/x DIO2 polymorphism variant is associated with a decreased rate of acute TSH-stimulated FT(4) secretion with a normal T(3) release from the thyroid gland consistent with a shift in the reaction equilibrium toward the product. These data indicate that the -258G DIO2 polymorphism causes changes in the pattern of hormone secretion. These findings are a proof of concept that common polymorphisms in DIO2 can subtly affect the circulating levels of TH and might modulate the TH homeostasis.

BACKGROUND:The common Thr92Ala D2 polymorphism has been associated with changes in pituitary-thyroid axis homeostasis, but published results are conflicting. To investigate the effects of the Thr92Ala polymorphism on intrathyroidal thyroxine (T4) to triiodothyronine (T3) conversion, we designed prospective pharmacogenomic intervention aimed to detect differences in T3 levels after thyrotropin (TSH)-releasing hormone (TRH)-mediated TSH stimulation of the thyroid gland.METHODS:Eighty-three healthy volunteers were screened and genotyped for the Thr92Ala polymorphism. Fifteen volunteers of each genotype (Thr/Thr, Thr/Ala, and Ala/Ala) underwent a 500 mcg intravenous TRH stimulation test with serial measurements of serum total T3 (TT3), free T4, and TSH over 180 minutes.RESULTS:No differences in baseline thyroid hormone levels were seen among the study groups. Compared to the Thr/Thr group, the Ala/Ala group showed a significantly lower TRH-stimulated increase in serum TT3 at 60 minutes (12.07 ± 2.67 vs. 21.07 ± 2.86 ng/dL, p = 0.029). Thr/Ala subjects showed an intermediate response. Compared to Thr/Thr subjects, the Ala/Ala group showed a blunted rate of rise in serum TT3 as measured by mean time to 50% maximum delta serum TT3 (88.42 ± 6.84 vs. 69.56 ± 6.06 minutes, p = 0.028). Subjects attained similar maximal (180 minutes) TRH-stimulated TT3 levels. TRH-stimulated TSH and free T4 levels were not significantly different among the three genotype groups.CONCLUSIONS:The commonly occurring Thr92Ala D2 variant is associated with a decreased rate of acute TSH-stimulated T3 release from the thyroid consistent with a decrease in intrathyroidal deiodination. These data provide a proof of concept that the Thr92Ala polymorphism is associated with subtle changes in thyroid hormone homeostasis.