Guidance for dysmorphic sacrum fixation with upper sacroiliac screw based on imaging anatomy study: techniques and indications.

OBJECTIVE: This study aimed to investigate the techniques and indications of upper sacroiliac screw fixation for the dysmorphic sacrum. METHODS: The dysmorphic sacra were selected from 267 three-dimensional pelvic models. The dysmorphic sacra which couldn't accommodate a 7.3 mm upper trans ilio-sacroiliac screw were classified as the main dysmorphic sacra. Then, the size of the bone corridor, the length of the screw in the corridor, and the orientation of the screw were measured. The insertion point on the sacrum was identified by two bone landmarks. RESULTS: totally, 30.3% of sacra were identified as the main dysmorphic sacra. The inclinations of the screw oriented from posterior to anterior were (21.80 ± 3.56)° for males and (19.97 ± 3.02)° for females (p < 0.001), and from caudal to cranial were (29.97 ± 5.38)° for males and (28.15 ± 6.21)° for females (p = 0.047). The min diameters of the corridor were (16.31 ± 2.40) mm for males and (15.07 ± 1.58) mm for females (p < 0.001). The lengths of the screw in the Denis III zone were (14.41 ± 4.40) mm for males and (14.09 ± 5.04) mm for females (p = 0.665), and in the Denis II+III zones were (36.25 ± 3.40) mm for males and (38.04 ± 4.60) mm for females (p = 0.005). The rates of LP-PSIS/LAIIS-PSIS were (0.36 ± 0.04) for males and (0.32 ± 0.03) for females (t = 4.943, p < 0.001). The lengths of LPM were (8.81 ± 5.88) for males and (-4.13 ± 6.33) for females (t = 13.434, p < 0.001). CONCLUSION: When the sacrum has the features of "sacrum not recessed" and/or "acute alar slope", the conventional trans ilio-sacroiliac screw couldn't be placed safely. The inclination oriented from posterior to anterior and from caudal to cranial are approximately 20° and 30°, respectively. The bone insertion point locates in the rear third of the anterior inferior iliac spine to the posterior superior iliac spine. The sacroiliac screw is not recommended to fix the fractures in Denis III zone.

Morphological characteristics of subaxial cervical pedicles and surrounding critical structures in patients with vertebral artery dominance - an anatomical study based on computed tomographic imaging.

BACKGROUND: No study has assessed the feasibility and safety of cervical pedicle screw implantation in patients with vertebral artery dominance (VAD), a common vertebral artery (VA) variation which can increase VA injury (VAI) risk. This study was to assess morphological characteristics of the subaxial cervical pedicles and surrounding critical structures, and identify their correlations in patients with VAD. METHODS: Computed tomography arteriography scans of 152 patients were used for retrospectively measuring parameters including pedicle outer width (POW), the distance from the lateral pedicle border to the closest part of VA (DPVA), diameter of VA (DVA), area of VA (AVA), area of transverse foramen (ATF) and occupational ratio of transverse foramen (TF). Moreover, correlations among some critical parameters were assessed. RESULTS: One hundred eight males and 44 females, with a mean age of 55.9 years were included. POW was smaller on the dominant side than on the non-dominant side, whereas DPVA, DVA, AVA, ATF, and TF were larger on the dominant side than those on the non-dominant side. On both sides, POW < 4 mm and POW + DPVA < 5 mm were observed most frequently at C3 and C4. On both sides, POW was correlated to ATF, and ATF was correlated to DVA and AVA. DPVA was correlated to ATF on the dominant side. CONCLUSION: Patients with VAD exhibited smaller POW on the dominant side, most frequently at C3 and C4. Dominant VA may indirectly affect POW. TF may be a key determinant of DPVA and POW.

The Evolution of Educational Technology in Veterinary Anatomy Education.

"All learning is in the learner, not the teacher." Plato was right. The adage has passed the test of time and is still true in an era where technology accompanies us in not only professional but also recreational life every day, everywhere. On the other hand, the learner has evolved and so have the sources being used to satisfy curiosity and learning. It therefore appears intuitive to embrace these technological advances to bring knowledge to our pupils with the aim to facilitate learning and improve performance. It must be clear that these technologies are not intended to replace but rather consolidate knowledge partly acquired during more conventional teaching of anatomy. Veterinary medicine is no outlier. Educating students to the complexity of anatomy in multiple species requires that three-dimensional concepts be taught and understood accurately if appropriate treatment is to be set in place thereafter. Veterinary anatomy education has up to recently walked diligently in the footsteps of John Hunter's medical teaching using specimens, textbooks, and drawings. The discipline has yet to embrace fully the benefits of advancement being made in technology for the benefit of its learners. Three-dimensional representation of anatomy is undeniably a logical and correct way to teach whether it is through the demonstration of cadaveric specimen or alternate reality using smartphones, tablets, headsets or other digital media. Here we review some key aspects of the evolution of educational technology in veterinary anatomy.

[Oblique puncture approach via anterolateral to C2: a study of imaging anatomy on corpses].

Objective: To determine the anatomical relation between the carotid artery or laryngopharynx and the needle path via anterolateral oblique approach to C2 vertebral body, and whether the simulated path can direct the actual procedure. Methods: Contrast agent was injected into bilateral carotid arteries of 10 fresh cadavers (20 sides), and then CT scans were performed on each subject. Bilateral simulated puncture paths were simulated on the image of two-dimensional reconstruction CT. The distance between the puncture site and middle line(AC), the angle between the simulated puncture paths and the median sagittal plane (AOB), the distance between the simulated puncture paths and the side wall of hypopharynx, or the carotid artery was measured respectively. Under the guidance of fluoroscopy, oblique puncture via anterolateral to C2 was performed according to the simulated parameters, and then CT was done. The actual needle path was measured on the image of two-dimensional reconstruction CT. The outcomes were compared by using paired t test between groups. Results: Bilateral simulated puncture paths in all 10 cadavers were achieved on the image of CT. The bilateral punctures via anterolateral to C2 were successfully performed under fluoroscopic guidance in 10 cadavers, and the actual needle path could be showed on the image of two-dimensional reconstruction CT. The AC, angle AOB, the distance to carotid artery and side wall of laryngopharyngeal of the left simulated path was(4.7±1.0)cm, (33±8)°, (6.7±2.6)mm, (6.6±2.8)mm, respectively; and those in the right side was(5.2±1.3) cm, (36±8)°, (7.5±2.2) mm, (7.2±2.5) mm, respectively.The AC, angle AOB, the distance to carotid artery and side wall of laryngopharyngeal of the left actual needle was(4.5±1.1) cm, (33±9) °, (6.7±3.0) mm, (7.1±3.9) mm, respectively; and those in the right side was(5.1±1.5) cm, (35±10) °, (7.4±2.1) mm, (7.2±2.6) mm, respectively.And the actual and simulation data of both sides were compared and no significant differences was found by t test (t=0.104-1.882, all P>0.05). Conclusion: The simulated approach via anterolateral to C2 can be achieved on the image of two-dimensional reconstruction CT, it is consistent with the real needle path and can be used to direct the actual practice to improve the accuracy and safety.

Sacral malformations: use of imaging to optimise sacral nerve stimulation.

INTRODUCTION: The success of sacral nerve stimulation, a common treatment for pelvic floor disorders, depends on correct placement of the electrodes through the sacral foramina. When the bony anatomy and topography of the sacrum and sacral spinal nerves are intact, this is easily achieved; where sacral anomalies exist, it can be challenging. A better understanding of common sacral malformations can improve the success of sacral nerve stimulation (SNS) electrode placement. MATERIAL AND METHODS: We reviewed 998 consecutive MRI scans performed to investigate low back pain in patients who had undergone CT and/or X-ray. RESULTS: Congenital sacral malformations were found in 24.1%, the most common being sacral meningeal cysts (16%) and spina bifida occulta (9.9%). Others were lumbosacral transitional vertebrae (2.5%), anterior occult meningocele (0.5%), partial sacral agenesis (0.2%) and vertebral dysplasia of S1 (0.2%). CONCLUSION: This radiologic review uncovered a high incidence of sacral malformations, and most were asymptomatic. All surgeons who perform SNS should have a basic understanding of sacral malformations, their incidence and effect on foraminal anatomy. Imaging will aid procedural planning.

Magnetic resonance imaging of the temporal lobe: normal anatomy and diseases.

OBJECTIVE: This pictorial essay will review the magnetic resonance imaging anatomy of the temporal lobes and describe the major pathologic processes of this complex area. CONCLUSIONS: Magnetic resonance imaging is an essential tool in the investigation of a patient with suspected temporal lobe pathology. Various conditions may affect this anatomic region, and, therefore, classification of imaging findings into specific groups may help provide a more focused differential diagnosis.

CT Anatomical Analysis of C4 Pedicle and Lateral Mass in Children Aged 0-14 in Southern China.

OBJECTIVE: The C4 is the transition point between the upper and lower cervical vertebrae and plays a pivotal role in the middle of the cervical spine. Currently, there are limited reports on large-scale sample studies regarding C4 anatomy in children, and a scarcity of experience exists in pediatric cervical spine surgery. The current study addresses the dearth of anatomical measurements of the C4 vertebral arch and lateral mass in a substantial sample of children. This study aims to measure the imaging anatomy of the C4 vertebral arch and lateral mass in children under 14 years of age across various age groups, investigate the growth and development of these structures. METHODS: We measured 12 indicators, including the size (D1, D2, D3, D4, D5, D6, D7, and D8) and angle (A, C, D, and E) of the C4 vertebral arch and lateral mass, in 513 children who underwent cervical CT examinations at our hospital. We employed the aggregate function for statistical analysis, conducted t-tests for difference statistics, and utilized the least squares method for regression analysis. RESULTS: Overall, as age increased, there was a gradual increase in the size of the vertebral arch and lateral mass. Additionally, the medial inclination angle of the vertebral arch decreased, and the lateral mass flattened gradually. The rate of change decreased gradually with age. The mean value of D1 increased from 2.31 mm to 3.88 mm, of D2 from 16.75 mm to 29.2 mm, of D3 from 2.21 mm to 4.92 mm, and of D4 from 7.34 mm to 11.84 mm. Meanwhile, the mean value of D5 increased from 5.2 mm to 9.71 mm, of D6 from 10.19 mm to 16.16 mm, of D7 from 2.53 mm to 5.67 mm, and of D8 from 6.11 mm to 11.45 mm. Angle A ranged from 49.12° to 54.97°, angle C from 15.28° to 19.83°, angle D from 39.91° to 53.7°, and angle E from 18.63° to 28.08°. CONCLUSION: Prior to cervical spine surgery in children, meticulous CT imaging anatomical measurements is essential. The imaging data serves as a reference for posterior C4 internal fixation, aids in designing posterior cervical screws for pediatric patients, and offer morphological anatomical references for posterior cervical spine surgery and screw design in pediatric patients.

Long-range connectome of pyramidal neurons in the sensorimotor cortex.

The neocortex mediates information processing through highly organized circuitry that contains various neuron types. Distinct populations of projection neurons in different cortical regions and layers make specific connections and participate in distinct physiological functions. Herein, with the fluorescence micro-optical sectioning tomography (fMOST) and transgenetic mice that targeted intratelencephalic (IT) and pyramidal tract (PT) neurons at specific layers, we dissected the long-range connectome of pyramidal neurons in six subregions of the sensorimtor cortex. The distribution of the input neurons indicated that IT and PT neurons in the same region received information from similar regions, while the neurons in different subregions received from the preferred neuron populations. Both the input and projection areas of these six subregions showed the transverse and longitudinal correspondence in the cortico-cortical, cortico-thalamic, and cortico-striatal circuits, which indicated that the connections were topologically organized. This study provides a comprehensive resource on the anatomical connections of cortical circuits.

3D imaging and morphometric descriptors of vascular networks on optically cleared organs.

The vascular system is a multi-scale network whose functionality depends on its structure, and for which structural alterations can be linked to pathological shifts. Though biologists use multiple 3D imaging techniques to visualize vascular networks, the 3D image processing methodologies remain sources of biases, and the extraction of quantitative morphometric descriptors remains flawed. The article, first, reviews the current 3D image processing methodologies, and morphometric descriptors of vascular network images mainly obtained by light-sheet microscopy on optically cleared organs, found in the literature. Second, it proposes operator-independent segmentation and skeletonization methodologies using the freeware ImageJ. Third, it gives more extractable network-level (density, connectivity, fractal dimension) and segment-level (length, diameter, tortuosity) 3D morphometric descriptors and how to statistically analyze them. Thus, it can serve as a guideline for biologists using 3D imaging techniques of vascular networks, allowing the production of more comparable studies in the future.

Characterizing the differential distribution and targets of Sumo1 and Sumo2 in the mouse brain.

SUMOylation is an evolutionarily conserved eukaryotic posttranslational protein modification with broad biological relevance. Differentiating between the major small ubiquitin-like modifier (SUMO) paralogs and uncovering paralog-specific functions in vivo has long been very difficult. To overcome this problem, we generated His6-HA-Sumo2 and HA-Sumo2 knockin mouse lines, expanding upon our existing His6-HA-Sumo1 mouse line, to establish a "toolbox" for Sumo1-Sumo2 comparisons in vivo. Leveraging the specificity of the HA epitope, we performed whole-brain imaging and uncovered regional differences between Sumo1 and Sumo2 expression. At the subcellular level, Sumo2 was specifically detected in extranuclear compartments, including synapses. Immunoprecipitation coupled with mass spectrometry identified shared and specific neuronal targets of Sumo1 and Sumo2. Target validation using proximity ligation assays provided further insight into the subcellular distribution of neuronal Sumo2-conjugates. The mouse models and associated datasets provide a powerful framework to determine the native SUMO "code" in cells of the central nervous system.

Application of a deep learning algorithm in the detection of hip fractures.

This paper describes the development of a deep learning model for prediction of hip fractures on pelvic radiographs (X-rays). Developed using over 40,000 pelvic radiographs from a single institution, the model demonstrated high sensitivity and specificity when applied to a test set of emergency department radiographs. This study approximates the real-world application of a deep learning fracture detection model by including radiographs with sub-optimal image quality, other non-hip fractures, and metallic implants, which were excluded from prior published work. The study also explores the effect of ethnicity on model performance, as well as the accuracy of visualization algorithm for fracture localization.

A quantitative micro-tomographic gut atlas of the lepidopteran model insect Manduca sexta.

The tobacco hornworm is used extensively as a model system for ecotoxicology, immunology and gut physiology. Here, we established a micro-computed tomography approach based on the oral application of the clinical contrast agent iodixanol, allowing for a high-resolution quantitative analysis of the Manduca sexta gut. This technique permitted the identification of previously unknown and understudied structures, such as the crop or gastric ceca, and revealed the underlying complexity of the hindgut folding pattern, which is involved in fecal pellet formation. The acquired data enabled the volume rendering of all gut parts, the reliable calculation of their volumes, and the virtual endoscopy of the entire alimentary tract. It can provide information for accurate orientation in histology uses, enable quantitative anatomical phenotyping in three dimensions, and allow the calculation of locally effective midgut concentrations of applied chemicals. This atlas will provide critical insights into the evolution of the alimentary tract in lepidopterans.

MRI Anatomical Investigation of Rabbit Bulbourethral Glands.

Anatomical MRI is appropriate for the interpretation of soft tissue findings in the retroperitoneal part of the pelvic cavity. The aim of the current study was to use rabbits as an imaging model to optimize MRI protocols for the investigation of bulbourethral glands. The research was conducted on twelve clinically healthy, sexually mature male rabbits, eight months of age (New Zealand White), weighing 2.8 kg to 3.2 kg. Tunnel MRI equipment was used. The transverse MRI in the T2-weighted sequence obtained detailed images that were of higher anatomical contrast than those in T1-weighted sequences. The hyperintensity of the glandular findings at T2, compared to the adjacent soft tissues, was due to the content of secretory fluids. The quality of the anatomical tissue contrast has not shown much dependence on the choice of the sequence in dorsal MRI. The sagittal visualization of the rabbit bulbourethral glands corresponded to the localization of the research plane toward a median plane. The imaging results could be used as a morphological base for clinical practice and reproduction.

Multi-scale light microscopy/electron microscopy neuronal imaging from brain to synapse with a tissue clearing method, ScaleSF.

The mammalian brain is organized over sizes that span several orders of magnitude, from synapses to the entire brain. Thus, a technique to visualize neural circuits across multiple spatial scales (multi-scale neuronal imaging) is vital for deciphering brain-wide connectivity. Here, we developed this technique by coupling successive light microscopy/electron microscopy (LM/EM) imaging with a glutaraldehyde-resistant tissue clearing method, ScaleSF. Our multi-scale neuronal imaging incorporates (1) brain-wide macroscopic observation, (2) mesoscopic circuit mapping, (3) microscopic subcellular imaging, and (4) EM imaging of nanoscopic structures, allowing seamless integration of structural information from the brain to synapses. We applied this technique to three neural circuits of two different species, mouse striatofugal, mouse callosal, and marmoset corticostriatal projection systems, and succeeded in simultaneous interrogation of their circuit structure and synaptic connectivity in a targeted way. Our multi-scale neuronal imaging will significantly advance the understanding of brain-wide connectivity by expanding the scales of objects.

Ontogeny of cellular organization and LGR5 expression in porcine cochlea revealed using tissue clearing and 3D imaging.

Over 11% of the world's population experience hearing loss. Although there are promising studies to restore hearing in rodent models, the size, ontogeny, genetics, and frequency range of hearing of most rodents' cochlea do not match that of humans. The porcine cochlea can bridge this gap as it shares many anatomical, physiological, and genetic similarities with its human counterpart. Here, we provide a detailed methodology to process and image the porcine cochlea in 3D using tissue clearing and light-sheet microscopy. The resulting 3D images can be employed to compare cochleae across different ages and conditions, investigate the ontogeny of cochlear cytoarchitecture, and produce quantitative expression maps of LGR5, a marker of cochlear progenitors in mice. These data reveal that hair cell organization, inner ear morphology, cellular cartography in the organ of Corti, and spatiotemporal expression of LGR5 are dynamic over developmental stages in a pattern not previously documented.

Pten haploinsufficiency causes desynchronized growth of brain areas involved in sensory processing.

How changes in brain scaling relate to altered behavior is an important question in neurodevelopmental disorder research. Mice with germline Pten haploinsufficiency (Pten +/-) closely mirror the abnormal brain scaling and behavioral deficits seen in humans with macrocephaly/autism syndrome, which is caused by PTEN mutations. We explored whether deviation from normal patterns of growth can predict behavioral abnormalities. Brain regions associated with sensory processing (e.g., pons and inferior colliculus) had the biggest deviations from expected volume. While Pten +/- mice showed little or no abnormal behavior on most assays, both sexes showed sensory deficits, including impaired sensorimotor gating and hyporeactivity to high-intensity stimuli. Developmental analysis of this phenotype showed sexual dimorphism for hyporeactivity. Mapping behavioral phenotypes of Pten +/- mice onto relevant brain regions suggested abnormal behavior is likely when associated with relatively enlarged brain regions, while unchanged or relatively decreased brain regions have little predictive value.

Anatomical characteristics affecting the surgical approach of oblique lateral lumbar interbody fusion: an MR-based observational study.

BACKGROUND: Oblique lateral lumbar interbody fusion (OLIF) is one of the most widely used lumbar interbody fusion procedures in clinical practice. The aim of this study was to minimize the incidence rate of surgical complications by measuring the anatomical parameters of structures surrounding the working channels of OLIF with 3D COSMIC sequence. METHODS: The MRI examination included conventional MRI sequence and 3D COSMIC sequence. Surgical window, psoas thickness, the transverse diameter of the endplate, and nerve distance were measured to evaluate the anatomical characteristics surrounding the OLIF working channels. RESULTS: The widths of the natural surgical window at the level of the L2-3, L3-4, and L4-5 intervertebral measured in this study were 16.25 ± 4.22, 15.46 ± 4.64 mm, and 11.71 ± 6.29 mm, respectively. The average thickness of the left psoas major muscle at the level of L2-3, L3-4, and L4-5 intervertebral space was 28.42 ± 5.08 mm, 30.76 ± 5.84 mm, and 31.16 ± 7.72 mm, respectively. The mean value of insertion angle (ß) was 45.57° ± 6.19° in L2-3 intervertebral space, 49.90° ± 6.53° in L3-4 intervertebral space, and 43.34° ± 8.88° in L4-5 intervertebral space. CONCLUSIONS: The 3D COSMIC sequences can be used for imaging anatomical assessment before OLIF surgery. In preoperative planning, the 3D COSMIC sequence can be used to measure the relevant parameters mentioned above to optimize the planned surgical approach.

Three-dimensional understanding of the morphological complexity of the human uterine endometrium.

The fundamental morphology of the endometrial glands is not sufficiently understood by 2D observation because these glands have complicated winding and branching patterns. To construct a large picture of the endometrial gland structure, we performed tissue-clearing-based 3D imaging of human uterine endometrial tissue. Our 3D immunohistochemistry and layer analyses revealed that the endometrial glands form a plexus network in the stratum basalis and expand horizontally along the muscular layer, similar to the rhizome of grass. We then extended our method to assess the 3D morphology of tissue affected by adenomyosis, a representative "endometrium-related disease," and observed its 3D morphological features, including the direct invasion of endometrial glands into the myometrium and an ant colony-like network of ectopic endometrial glands within the myometrium. Thus, further understanding of the morphology of the human endometrium based on 3D analysis will lead to the identification of the pathogenesis of endometrium-related diseases.

Helically arranged cross struts in azhdarchid pterosaur cervical vertebrae and their biomechanical implications.

Azhdarchid pterosaurs, the largest flying vertebrates, remain poorly understood, with fundamental aspects of their palaeobiology unknown. X-ray computed tomography reveals a complex internal micro-architecture for three-dimensionally preserved, hyper-elongate cervical vertebrae of the Cretaceous azhdarchid pterosaur, Alanqa sp. Incorporation of the neural canal within the body of the vertebra and elongation of the centrum result in a "tube within a tube" supported by helically distributed trabeculae. Linear elastic static analysis and linearized buckling analysis, accompanied with a finite element model, reveal that as few as 50 trabeculae increase the buckling load by up to 90%, implying that a vertebra without the trabeculae is more prone to elastic instability due to axial loads. Subsuming the neural tube into the centrum tube adds considerable stiffness to the cervical series, permitting the uptake of heavy prey items without risking damage to the cervical series, while at the same time allowing considerable skeletal mass reduction.

Densities and numbers of calbindin and parvalbumin positive neurons across the rat and mouse brain.

The calcium-binding proteins parvalbumin and calbindin are expressed in neuronal populations regulating brain networks involved in spatial navigation, memory processes, and social interactions. Information about the numbers of these neurons across brain regions is required to understand their functional roles but is scarcely available. Employing semi-automated image analysis, we performed brain-wide analysis of immunohistochemically stained parvalbumin and calbindin sections and show that these neurons distribute in complementary patterns across the mouse brain. Parvalbumin neurons dominate in areas related to sensorimotor processing and navigation, whereas calbindin neurons prevail in regions reflecting behavioral states. We also find that parvalbumin neurons distribute according to similar principles in the hippocampal region of the rat and mouse brain. We validated our results against manual counts and evaluated variability of results among researchers. Comparison of our results to previous reports showed that neuron numbers vary, whereas patterns of relative densities and numbers are consistent.