Dual ophthalmic arteries: a new case.

We report one retinoblastoma patient with dual ophthalmic arteries (also known as "double ophthalmic arteries") arising from the internal carotid artery which fuse with each other inside the orbit. The caudal ophthalmic artery with larger caliber originated from the cavernous segment of internal carotid artery and passed through the superior orbital fissure. The cranial and tiny one arose more cranially from the supraclinoid internal carotid artery and passed through the optic canal. After superselective catheterization, frank anastomosis was shown between two ophthalmic arteries and the central retinal artery arose from the cranial one. To the best of our knowledge, this case is the first observation of a dual ophthalmic artery with cavernous/supracavernous origins fusing with each other proven by superselective ophthalmic angiography. Whether there is an anastomosis between two ophthalmic arteries is important for deciding which artery to be selected for intraarterial treatment. In cases of retinoblastoma, detailed angiographic analysis may be essential to examine the orbital arterial system and to avoid unexpected complications during intraarterial chemotherapy.

Evaluation of the anastomoses between the ophthalmic artery and the middle meningeal artery by superselective angiography.

PURPOSE: There are three anastomoses between the ophthalmic artery (OA) and the middle meningeal artery (MMA): the anastomotic branch with MMA, the recurrent meningeal branch and the anterior falx artery. We aimed to evaluate the anastomotic branches between the OA and the MMA on superselective angiograms of pediatric patients with retinoblastoma. MATERIALS AND METHODS: We evaluated 126 angiographies performed on children with retinoblastoma. The mean diameter and angiographic visibility percentage of the anastomotic branches between the OA and the MMA were examined according to age group and sex. RESULTS: The mean diameter of anastomotic branch with MMA was measured 0.58 ± 0.13 mm and we found this branch in 15 of 126 angiographic images (11.9%). We detected the recurrent meningeal branch in 47 of total images (37.3%). The recurrent meningeal branch arose 85.1% from the lacrimal artery, 8.5% from the anastomotic branch with MMA and 6.4% directly from the OA. The mean diameter of this artery was measured 0.21 ± 0.06 mm. Anterior falx artery was found in 86 of 126 angiographic peocedures (68.3%) and the mean diameter was measured 0.22 ± 0.06 mm. CONCLUSION: Knowledge of the anastomoses between the OA and the MMA system are all necessary to perform safe and successful endovascular and surgical procedures involving the orbital region.

Protective effect of aerobic exercise on the vocal folds against cigarette smoke exposure.

PURPOSE: Laryngeal pathologies due to cigarette smoking vary among individuals, whereas some smokers remain disease free. These differences can be explained by multiple factors among individuals. In this context, an animal study was designed to determine if there is any protective effect of aerobic exercise against the detrimental effects of cigarette smoke on laryngeal tissues. METHODS: A total of 24 male Wistar albino rats were divided into three groups of eight animals each: control (no smoke exposure), smoking (smoke exposure), and exercise (smoke exposure and exercise) groups. Histopathological (light and electron microscopy) and immunohistochemical (GSTA1, CYP1A1, CYP2E1) evaluations of the vocal folds were performed at the end of experimental period. RESULTS: Exercise group revealed statistically significant decrease in edema (p = 0.03) and inflammatory cell infiltration (p = 0.02) compared to smoking group. In electron microscopic evaluation; cytoplasmic vacuoles were also present in exercise group, but were smaller than smoking group. Edema and swollen mitochondria were also less prominent in exercise group. Condensed chromatin material in the periphery of nucleus was observed only in few cells in exercise group, and observed in more cells in smoking group. GSTA1 expression was higher (p = 0.047) and CYP1A1 expression was lower (p = 0.01) in exercise group than smoking group. CONCLUSIONS: Our results indicate that aerobic exercise has a protective role on the larynx against the damaging effect of cigarette smoke. Smokers who exercise regularly may be at a lower risk of cigarette smoke-related laryngeal diseases, as compared with those who do not exercise.

The Anatomy of the Sigmoid-Transverse Junction According to the Tentorial Angle.

Dural sinuses have critical importance during intracranial approaches. Detailed anatomical knowledge of the dural sinuses is crucial for surgeons to reduce unexpected venous bleeding. The aim of this study was to investigate anatomical relation of sigmoid sinus and tentorium cerebelli according to clinically palpable landmarks and cranial morphometry. The authors evaluated 222 individuals' (94 women, 128 men) 3-dimensional computed tomography angiograms, retrospectively. The authors also studied on 12 mid-sagittal cut dried hemiskulls and 8 formalin fixed cadaver heads hemisected midsagitally. All measurements were completed using Osirix-Lite version 9 software. Craniometrical values were measured to define cranium morphology. Furthermore, level of the sigmoid sinus according to asterion and tentorial angle were evaluated in detail. Our results demonstrated that there were significant differences between parameters and genders, except vertical angle of the tentorium cerebelli. Distance between asterion and sigmoid sinus was statistically different between right and left sides in favor of the left side. This also varied depending on the position of the sigmoid sinus, as well. Only transverse angle between the upper point of external acoustic meatus and asterion demonstrated a significant correlation with age. This study evaluated the detailed 3D anatomy of sigmoid sinus and tentorium cerebelli related with the cranium morphology. Determining to sigmoid sinus anatomy according to clinically palpable landmarks has advantages for setting surgical protocols and reducing to unexpected injuries while surgery to these structures.

Review of the effect of 3D medical printing and virtual reality on urology training with 'MedTRain3DModsim' Erasmus + European Union Project

Background/aim: It is necessary to incorporate novel training modalities in medical education, especially in surgical fields, because of the limitations of cadaveric training. Traditional medical education has many drawbacks, such as residency working hour restrictions, patient safety conflicts with the learning needs, and the lack of hands-on workshops. The MedTRain3DModsim Project aimed to produce 3-dimensional (3D) medical printed models, simulations, and innovative applications for every level of medical training using novel worldwide technologies. It was aimed herein to improve the interdisciplinary and transnational approaches, and accumulate existing experience for medical education, postgraduate studies, and specialty training. Materials and methods: This project focused on models of solid organs and the urinary system, including the kidney, prostate, ureter, and liver. With 3D medical printing, it is possible to produce a body part from inert materials in just a few hours with the standardization of medical 3D modeling. Results: The target groups of this project included medical students and residents, graduate students from engineering departments who needed medical education and surgical training, and medical researchers interested in health technology or clinical and surgical an atomy. Conclusion: It was also intended to develop a novel imaging platform for education and training by reevaluating the existing data using new software and 3D modalities. Therefore, it was believed that our methodology could be implemented in all related medical fields.

The effects of the stem cell on ciliary regeneration of injured rabbit sinonasal epithelium.

Defects in mucosal healing after sinonasal surgery cause infection, scar formation causing obstruction, relapse of the disease within a shorter period and revision surgery. The present study aimed to create a functional ciliated epithelium using a stem cell and stem cell sheet of adipose tissue origin and to show such regeneration ultra-structurally on experimentally injured rabbit nasal epithelium. This was an experimental animal study and basic research. A total of 18 white New Zealand rabbits were divided into three groups. The medial wall of the maxillary sinus of the subjects was peeled off bilaterally. No additional procedure was applied to the subjects in Group 1. In Group 2, adipose tissue-derived mesenchymal stem cell was implanted on the wound edges of the subjects. In Group 3, a stem cell sheet of three layers was laid onto the defect area. All subjects were killed after 3 weeks. The presence of the stem cell stained with bromo-deoxyuridine was assessed with a light microscope, whereas cilia density, ciliated orientation and cilia structure were evaluated with a scanning electron microscope. Ciliary densities in Group 2 and Group 3 were statistically superior compared to the control group (p < 0.001, p = 0.007). Cilia morphology in Group 2 and Group 3 was also better than the control group (p < 0.01, p = 0.048). Ciliary orientation in Group 2 was scored highest (p < 0.01). The ratio of BrDu-stained cells was observed to be 27% in Group 3 and 8% in Group 2. Sub-epithelial recovery was observed to be better in Group 3. Adipose tissue-derived mesenchymal stem cell increased the healing of the injured maxillary sinus mucosa of the rabbits in terms of cilia presence, density and morphology regardless of the implementation technique. Level of evidence NA.

Protective/restorative Role of the Adipose Tissue-derived Mesenchymal Stem Cells on the Radioiodine-induced Salivary Gland Damage in Rats.

BACKGROUND: To analyze protective/regenerative effects of adipose tissue-derived mesenchymal stem cells (ADMSC) on 131I-Radioiodine (RAI)-induced salivary gland damage in rats. MATERIALS AND METHODS: Study population consisted of controls (n:6) and study groups (n:54): RAI (Group 1), ADMSC (Group 2), amifostine (Group 3), RAI+amifostine (Group 4), concomitant RAI+ADMSC (Group 5) and RAI+ADMSC after 48 h (Group 6). We used light microscopy (LM), transmission electron microscopy (TEM), and salivary gland scintigraphy (SGS), and analyzed data statistically. RESULTS: We observed the homing of ADMSC in salivary glands at 1st month on LM. RAI exposure affected necrosis, periductal fibrosis, periductal sclerosis, vascular sclerosis and the total sum score were in a statistically significant manner (P < 0.05). Intragroup comparisons with LM at 1st and 6th months revealed statistically significant improvements in Group 6 (P < 0.05) but not in Groups 4 and 5. Intergroup comparisons of the total score showed that Groups 4 and 5 in 1st month and Group 6 in 6th month had the lowest values. TEM showed vacuolization, edema, and fibrosis at 1st month, and an improvement in damage in 6th month in Groups 5 and 6. SGSs revealed significant differences for the maximum secretion ratio (Smax) (P = 0.01) and the gland-to-background ratio at a maximum count (G/BGmax) (P = 0. 01) at 1st month, for G/BGmax (P = 0.01), Smax (P = 0.01) and the time to reach the maximum count ratio over the time to reach the minimum count (Tmax/Tmin) (P = 0.03) at 6th month. 1st and 6th month scans showed differences for Smax and G/BGmax (P = 0.04), but not for Tmax/Tmin (p > 0.05). We observed a significant deterioration in gland function in group 1, whereas, mild to moderate deteriorations were seen in protective treatment groups. CONCLUSIONS: Our results indicated that ADMSC might play a promising role as a protective/regenerative agent against RAI-induced salivary gland dysfunction.

Simulation of RIRS in soft cadavers: a novel training model by the Cadaveric Research On Endourology Training (CRET) Study Group.

PURPOSE: The aim of the current study was to evaluate the use of fresh-frozen concurrently with embalmed cadavers as initial training models for flexible ureteroscopy (fURS) in a group of urologists who were inexperienced in retrograde intrarenal surgery (RIRS). METHODS: Twelve urologists involved in a cadaveric fURS training course were enrolled into this prospective study. All the participants were inexperienced in fURS. Theoretical lectures and step-by-step tips and tricks video presentations on fURS were used to incorporate the technical background of the procedure to the hands-on-training course and to standardize the operating steps of the procedure. An 8-item survey was administered to the participants upon initiation and at the end of the course. RESULTS: Pre- and post-training scores were similar for each question. All the participants successfully completed the hands-on-training tasks. Mean pre-training duration [3.56 ± 2.0 min (range 1.21-7.46)] was significantly higher than mean post-training duration [1.76 ± 1.54 min (range 1.00-6.34)] (p = 0.008). At the end of the day, the trainers checked the integrity of the collecting system both by endoscopy and by fluoroscopy and could not detect any injury of the upper ureteral wall or pelvicalyceal structures. The functionality of the scopes was also checked, and no scope injury (including a reduction in the deflection capacity) was noted. CONCLUSIONS: The fURS simulation training model using soft human cadavers has the unique advantage of perfectly mimicking the living human tissues. This similarity makes this model one of the best if not the perfect simulator for an effective endourologic training.

The effect of tacrolimus on facial nerve injury: Histopathological findings in a rabbit model.

HYPOTHESIS: Tacrolimus helps healing of facial nerve injury. BACKGROUND: Positive effects of tacrolimus on axon regeneration and healing of injured peripheral nerves (eg. sciatic nerve) have been reported in the literature. Tacrolimus may be an additional treatment method that could improve the nerve healing after surgical treatment of cut injury of facial nerve. METHODS: 20 New Zealand rabbits were randomly separated into control and study groups of 10. In control group, no medical treatment was given after facial nerve anastomosis, and the animals were followed up for 2months. In the study group rabbits were given 1mg/kg/day tacrolimus subcutaneously for 2months after the facial nerve anastomosis. The histopathologic findings of axon regeneration like axon myelination were analyzed in both groups under electron and light microscopy. The data obtained in the groups were compared. RESULTS: Greater axon diameters, thicker myelin sheaths, and higher total number of myelinated axons were found in the tacrolimus group, suggesting better regeneration in this group when compared to the control group. There was less vacuolar degeneration in the study group. All these findings suggest that tacrolimus positively affects healing after facial nerve anastomosis. CONCLUSION: The results of this study indicate that tacrolimus has favorable effects on the healing process of the facial nerve after end-to-end anastomosis. Tacrolimus may be a promising agent in the future for nerve regeneration following traumatic facial paralysis surgery.

Descriptive Analysis of Sphenovomerine Suture and Its Importance in Neurosurgery.

PURPOSE: Articulation of rostrum of sphenoid bone with alae of vomer forms a schindylesis type of joint. The circumference of this joint, called sphenovomerine suture (SVS), is very important in establishing a reliable surgical field in the endoscopic transsphenoidal pituitary surgery. Because of its vital role in endoscopic transsphenoidal pituitary surgery, this radio-anatomical study was designed to establish the morphological properties of SVS. METHODS: In this study, the authors examined SVS in 235 patients (121 females and 114 males) on the computed tomography images of the paranasal sinus and made 4 measurements to describe SVS. RESULTS: The mean distance between superior margin of the upper labial philtrum and top of SVS was 6.66 ±â€Š0.43 cm for females and 7.44 ±â€Š0.54 cm for males. The distance between the top of SVS and dorsum sellae was 3.08 ±â€Š0.33 cm for females and 3.19 ±â€Š0.32 cm for males, the alae of vomer angle in the upper surface was 74.22 ±â€Š20.06° for females and 74.23 ±â€Š19.68° for males. The distance between the most lateral points of 2 alae of vomer was 0.99 ±â€Š0.17 and 1.01 ±â€Š0.19 cm for females and males, respectively. CONCLUSIONS: For an easy and successful operation, removal of the SVS is very important as it will provide a better view of the sellar base and make the management of the surgical instruments easier in the wider safe surgical field thus created.

Effect of Porous Titanium Granules on Bone Regeneration and Primary Stability in Maxillary Sinus: A Human Clinical, Histomorphometric, and Microcomputed Tomography Analyses.

The aim of this randomized controlled study was to comparatively analyze the new bone (NB), residual bone, and graft-bone association in bone biopsies retrieved from augmented maxillary sinus sites by histomorphometry and microcomputed tomography (MicroCT) in a split-mouth model to test the efficacy of porous titanium granules (PTG) in maxillary sinus augmentation. Fifteen patients were included in the study and each patient was treated with bilateral sinus augmentation procedure using xenograft (equine origine, granule size 1000-2000 µm) and xenograft (1 g) + PTG (granule size 700-1000 µm, pore size >50 µm) (1 g), respectively. After a mean of 8.4 months, 30 bone biopsies were retrieved from the implant sites for three-dimensional MicroCT and two-dimensional histomorphometric analyses. Bone volume and vital NB percentages were calculated. Immediate after core biopsy, implants having standard dimensions were placed and implant stability quotient values were recorded at baseline and 3 months follow-up. There were no significant differences between groups according to residual bone height, residual bone width, implant dimensions, and implant stability quotient values (baseline and 3 months). According to MicroCT and two-dimensional histomorphometric analyses, the volume of newly formed bone was 57.05% and 52.67%, and 56.5% and 55.08% for xenograft + PTG and xenograft groups, respectively. No statistically significant differences found between groups according to NB percentages and higher Hounsfield unit values were found for xenograft + PTG group. The findings of the current study supports that PTG, which is a porous, permanent nonresorbable bone substitute, may have a beneficial osteoconductive effect on mechanical strength of NB in augmented maxillary sinus.

Micro-CT Detection and Characterization of Porosity in Luting Cements.

PURPOSE: To evaluate porosity volume and localization in luting cements under fixed dental prostheses after cementation using micro-computed tomography (CT). MATERIALS AND METHODS: Seventy-seven sound molars were circumferentially prepared to receive all-ceramic crowns, and IPS e.max ceramic copings were fabricated according to the manufacturer's instructions. For this study, different dental luting cements were used: eight resin-based cements (Variolink II, RelyX ARC, Clearfil Esthetic, BisCem, RelyX U100, Panavia EX, Super Bond C&B, and Multilink Automix), one resin-modified glass ionomer (Ketac Cem Plus), one glass ionomer (Ketac Cem), and one polycarboxylate (Durelon). Specimens were scanned with a micro-CT (SkyScan) for detection and comparison of the cements' porosities. Statistical analyses were performed using Kruskal-Wallis one-way ANOVA and Bonferroni's adjusted Mann-Whitney U tests. RESULTS: Multilink Automix (Volume = 0.11 ± 0.08 mm3 ; Surface Area = 1.63 ± 1.31 mm2 ), Ketac Cem Plus (Volume = 0.22 ± 0.21 mm3 ; Surface Area = 4.32 ± 3.71 mm2 ), and Variolink II (Volume = 0.34 ± 0.38 mm3 ; Surface Area = 6.47 ± 5.10 mm2 ) contained less porosity (p < 0.001) than all other cements. All other cements were not significantly different from one another (p > 0.05); however, the volume and surface area of the porosity found in the other tested luting cements were significantly greater than those of the Multilink Automix, Ketac Cem Plus, and Variolink II (p < 0.001), all of which demonstrated no significant differences (p > 0.05). CONCLUSION: The liquid and powder forms prepared by manually mixing the cements were found to cause greater porosity.

Biofilms in chronic rhinosinusitis with polyps: is eradication possible?

The objective of the study was to reveal if mometasone furoate nasal spray as monotherapy or combined with long-term oral clarithromycin have influence on biofilms in chronic rhinosinusitis with polyps. The study is a randomized controlled trial in a tertiary referral hospital. Thirty-four patients with chronic rhinosinusitis completed the study. In the first group, 19 patients received mometasone furoate nasal spray 200 µg once daily for 8 weeks. In the second group, 15 patients received oral clarithromycin 500 mg twice daily for 2 weeks and continued once daily 250 mg tablet for subsequent 6 weeks, plus mometasone furoate. Scanning electron microscopy was the primary outcome measure. Secondary outcome measures included computerized tomography and sinonasal outcome test-20 items. Mucosal biofilms were detected in 23 of 34 (68%) patients on pretreatment polyp samples. After the treatment, biofilms disappeared in 1 of 11 patients in the first group, whereas the eradication of biofilms was evident in 6 of 12 (50%) patients in the second group. Tomography scores improved in eight patients of each group (42.1 and 53.4%, respectively). The comparison of improvements did not reveal significant difference between the groups. The overall symptom scores improved compared to the baseline levels. The mean changes of -8.8421 and -11.4000 in the first and second group, respectively, were not statistically different. Adding long-term low-dose oral macrolides to nasal steroids was effective in the eradication of biofilm. However, we were not able to demonstrate that combined therapy was superior in terms of the improvement in tomography and symptom scores.

Quantitative assessment and objective improvement of the accuracy of neurosurgical planning through digital patient-specific 3D models.

Objective: Neurosurgical patient-specific 3D models have been shown to facilitate learning, enhance planning skills and improve surgical results. However, there is limited data on the objective validation of these models. Here, we aim to investigate their potential for improving the accuracy of surgical planning process of the neurosurgery residents and their usage as a surgical planning skill assessment tool. Methods: A patient-specific 3D digital model of parasagittal meningioma case was constructed. Participants were invited to plan the incision and craniotomy first after the conventional planning session with MRI, and then with 3D model. A feedback survey was performed at the end of the session. Quantitative metrics were used to assess the performance of the participants in a double-blind fashion. Results: A total of 38 neurosurgical residents and interns participated in this study. For estimated tumor projection on scalp, percent tumor coverage increased (66.4 ± 26.2%-77.2 ± 17.4%, p = 0.026), excess coverage decreased (2,232 ± 1,322 mm2-1,662 ± 956 mm2, p = 0.019); and craniotomy margin deviation from acceptable the standard was reduced (57.3 ± 24.0 mm-47.2 ± 19.8 mm, p = 0.024) after training with 3D model. For linear skin incision, deviation from tumor epicenter significantly reduced from 16.3 ± 9.6 mm-8.3 ± 7.9 mm after training with 3D model only in residents (p = 0.02). The participants scored realism, performance, usefulness, and practicality of the digital 3D models very highly. Conclusion: This study provides evidence that patient-specific digital 3D models can be used as educational materials to objectively improve the surgical planning accuracy of neurosurgical residents and to quantitatively assess their surgical planning skills through various surgical scenarios.

Comparative investigation of the effects of different materials used with a titanium barrier on new bone formation.

OBJECTIVES: In this study, we aimed to study the effects on new bone formation of autogenous blood, deproteinized bovine bone graft (DBBG), and biphasic calcium phosphate (BCP) bioceramic graft materials placed under titanium barriers. MATERIAL AND METHODS: Twenty-four adult male New Zealand white rabbits were used in this study. Two titanium barriers were fixed on each rabbit's calvarium. The study included four groups, one of which was a control group. The experiment groups, autogenous blood, DBBG (Bio-Oss(®) ; Geistlich Biomaterials, Wolhusen, Switzerland) and BCP (4Bone(TM) ; Biomatlante, Vigneux de Bretagne, France) were placed under titanium barriers; in the control group, no materials were used. Half of the animals were sacrificed after 1 month, and the rest were sacrificed after 3 months. After this, micro-computerized tomography images were taken, and a histomorphometric evaluation was carried out. RESULTS: The amounts of new bone formation were found to be higher at the third month than at the first month. The differences between the groups were examined with both a micro-computerized tomography and histomorphometric analysis, and no statistical significance was noted in the first month. In contrast, the increase in the amount of new bone formation at the third month was found to be statistically significant only between the DBBG and control groups (P < 0.05). CONCLUSION: Autogenous blood with titanium barriers in guided bone regeneration seems to be as successful as DBBG and BCP bioceramic graft material.

Investigation into the ophthalmic artery and its branches by superselective angiography.

BACKGROUND: The vascular anatomy of orbit is highly complex, and the main blood supply to the orbit is via the ophthalmic artery, which is a branch of the internal carotid artery. The purpose of this study was to determine the morphometry of the ophthalmic artery and its branches by superselective angiography in a large series of pediatric patients. METHODS: We evaluated 134 angiographies performed on children with intraocular retinoblastoma undergoing intra-arterial chemotherapy. The origin, diameter, and angiographic visibility percentages of the ophthalmic artery and its branches were examined according to age group and sex. RESULTS: The ophthalmic artery originated 97.8% from the internal carotid artery and 2.2% from the middle meningeal artery. The mean diameter of ophthalmic artery was measured 0.76 ± 0.14 mm in girls, 0.80 ± 0.15 mm in boys and 0.79 ± 0.15 mm in general. The posterior ciliary, lacrimal, inferior muscular, and anterior ethmoidal arteries had a higher angiographic visibility percentages (> 85%) than the other OA branches. Only the diameter of the dorsal nasal artery showed a significant correlation with age. The supratrochlear and posterior ciliary arteries showed statistically significant relationship with sex. CONCLUSIONS: Present study will make a substantial contribution to the pediatric literature about the ophthalmic artery and its branches. A better understanding of ophthalmic artery morphology can help surgeons and neurointerventional radiologists to avoid possible severe complications during embolization, intra-arterial chemotherapy, cosmetic procedures, endonasal and orbital surgeries.

Three-Dimensional Modeling and Augmented and Virtual Reality Simulations of the White Matter Anatomy of the Cerebrum.

BACKGROUND: An understanding of the anatomy of white matter tracts and their 3-dimensional (3D) relationship with each other is important for neurosurgical practice. The fiber dissection technique contributes to this understanding because it involves removing the brain's white matter tracts to reveal their anatomic organization. Using this technique, we built freely accessible 3D models and augmented and virtual reality simulations of white matter tracts. OBJECTIVE: To define the white matter tracts of cadaveric human brains through fiber dissection and to make 2-dimensional and 3D images of the white matter tracts and create 3D models and augmented and virtual reality simulations. METHODS: Twenty cadaveric brain specimens were prepared in accordance with the Klingler method. Brain hemispheres were dissected step-by-step from lateral-to-medial and medial-to-lateral directions. Three-dimensional models and augmented reality and virtual reality simulations were built with photogrammetry. RESULTS: High-resolution 3D models and augmented reality and virtual reality simulations of the white matter anatomy of the cerebrum were obtained. These models can be freely shifted and rotated on different planes, projected on any real surface, visualized from both front and back, and viewed from various angles at various magnifications. CONCLUSION: To our knowledge, this is the first detailed study integrating various technologies (3D modeling, augmented reality, and virtual reality) for high-resolution 3D visualization of dissected white matter fibers of the entire human cerebrum.

Development and Validation of a Novel Methodological Pipeline to Integrate Neuroimaging and Photogrammetry for Immersive 3D Cadaveric Neurosurgical Simulation.

Background: Visualizing and comprehending 3-dimensional (3D) neuroanatomy is challenging. Cadaver dissection is limited by low availability, high cost, and the need for specialized facilities. New technologies, including 3D rendering of neuroimaging, 3D pictures, and 3D videos, are filling this gap and facilitating learning, but they also have limitations. This proof-of-concept study explored the feasibility of combining the spatial accuracy of 3D reconstructed neuroimaging data with realistic texture and fine anatomical details from 3D photogrammetry to create high-fidelity cadaveric neurosurgical simulations. Methods: Four fixed and injected cadaver heads underwent neuroimaging. To create 3D virtual models, surfaces were rendered using magnetic resonance imaging (MRI) and computed tomography (CT) scans, and segmented anatomical structures were created. A stepwise pterional craniotomy procedure was performed with synchronous neuronavigation and photogrammetry data collection. All points acquired in 3D navigational space were imported and registered in a 3D virtual model space. A novel machine learning-assisted monocular-depth estimation tool was used to create 3D reconstructions of 2-dimensional (2D) photographs. Depth maps were converted into 3D mesh geometry, which was merged with the 3D virtual model's brain surface anatomy to test its accuracy. Quantitative measurements were used to validate the spatial accuracy of 3D reconstructions of different techniques. Results: Successful multilayered 3D virtual models were created using volumetric neuroimaging data. The monocular-depth estimation technique created qualitatively accurate 3D representations of photographs. When 2 models were merged, 63% of surface maps were perfectly matched (mean [SD] deviation 0.7 ± 1.9 mm; range -7 to 7 mm). Maximal distortions were observed at the epicenter and toward the edges of the imaged surfaces. Virtual 3D models provided accurate virtual measurements (margin of error <1.5 mm) as validated by cross-measurements performed in a real-world setting. Conclusion: The novel technique of co-registering neuroimaging and photogrammetry-based 3D models can (1) substantially supplement anatomical knowledge by adding detail and texture to 3D virtual models, (2) meaningfully improve the spatial accuracy of 3D photogrammetry, (3) allow for accurate quantitative measurements without the need for actual dissection, (4) digitalize the complete surface anatomy of a cadaver, and (5) be used in realistic surgical simulations to improve neurosurgical education.

Occlusal caries depth measurements obtained by five different imaging modalities.

The study aimed to assess the accuracy and reproducibility of occlusal caries depth measurements obtained from different imaging modalities. The study comprised 21 human mandibular molar teeth with occlusal caries. Teeth were imaged using film, CCD, two different cone-beam computerized tomography (CBCT) units and a microcomputer tomography (micro-CT). Thereafter, each tooth was serially sectioned, and the section with the deepest carious lesion was scanned using a high-resolution scanner. Each image set was separately viewed by three oral radiologists. Images were viewed randomly, and each set was viewed twice. Lesion depth was measured on film images using a digital caliper, on CCD and CBCT images using built-in measurement tools, on micro-CT images using the Mimics software program, and on histological images using AxioVision Rel. 4.7. Intra- and inter-rater reliabilities were assessed according to the Bland/Altman method by calculating Intraclass Correlation Coefficients (ICCs). Mean/median values obtained with intraoral systems were lower than those obtained with 3-D and histological images for all observers and both readings. Intra-observer ICC values for all observers were highest for histology and micro-CT. In addition, intra-observer ICC values were higher for histology and CBCT than for histology and intra-oral methods. Inter-observer ICC values for first and second readings were high for all observers. No differences in repeatability were found between Accuitomo and Iluma CBCT images or between intra-oral film and CCD images. Micro-CT was found to be the best imaging method for the ex vivo measurement of occlusal caries depth. In addition, both CBCT units performed similarly and better than intra-oral modalities.