Anatomical Reference Research Articles

Ultrasonographic technique and appearance of the coelomic organs in crocodilians

IntroductionCrocodilians have significant ecological, conservational, and economic roles. They are also commonly raised for commercial purposes and kept as zoological specimens. Although ultrasonography has been used in zoological contexts for health assessments of crocodilians, published studies on a detailed ultrasonography protocol and ultrasonographic anatomy are lacking. This study aimed to establish a standardized ultrasonography protocol and pictorial reference of the ultrasonographic appearances of the coelomic organs of crocodilians.MethodsA total of 7 crocodilians comprising 4 different species were included in this study. The crocodilians were manually restrained and underwent a non-contrasted and contrasted computed tomography (CT) scan, followed by an ultrasonography (USG) examination. Ultrasound fusion imaging technique enabled greater confidence in establishing a clear organ localization and correlation between modalities by visualizing the same anatomy from the same view angle.ResultsThe heart, caudal vena cava, liver, fat body (steatotheca), spleen, stomach, duodenal loops, pancreas, kidneys, testes, ovaries and cloaca were visualized in all species. Longitudinal and transverse images of the coelomic structures were acquired when possible. The ultrasonographic characteristics of the coelomic organs, including transducer positioning, acoustic window and approach, shape, size, marginations, and echo pattern were documented.DiscussionThe findings of this study provided a useful ultrasonographic protocol and anatomical reference of the coelomic organs in crocodilians. Invaluable insights into the practicality and adequacy of ultrasonography in evaluating the coelomic structures of crocodilians as part of health assessment and disease diagnosis were also discussed.

Evaluating Alternative Registration Planes in Imageless, Computer-Assisted Navigation Systems for Direct Anterior Total Hip Arthroplasty.

(1) Background: Imageless computer navigation systems have the potential to improve the accuracy of acetabular cup position in total hip arthroplasty (THA). Popular imageless navigation methods include locating the patient in a three-dimensional space (registration method) while using a baseline to angle the acetabular cup (reference plane). This study aims to compare the accuracy of different methods for determining postoperative acetabular cup positioning in THA via the direct anterior approach. (2) Methods: Fifty-one participants were recruited. Optical and inertial sensor imageless navigation systems were used simultaneously with three combinations of registration methods and reference planes: the anterior pelvic plane (APP), the anterior superior iliac spine (ASIS) and the table tilt (TT) method. Postoperative acetabular cup position, inclination, and anteversion were assessed using CT scans. (3) Results: For inclination, the mean absolute error (MAE) was lower using the TT method (2.4° ± 1.7°) compared to the ASIS (2.8° ± 1.7°, p = 0.17) and APP method (3.7° ± 2.1°, p < 0.001). For anteversion, the MAE was significantly lower for the TT method (2.4° ± 1.8°) in contrast to the ASIS (3.9° ± 3.2°, p = 0.005) and APP method (9.1° ± 6.2°, p < 0.001). (4) Conclusion: A functional reference plane is superior to an anatomic reference plane to accurately measure intraoperative acetabular cup inclination and anteversion in THA using inertial imageless navigation systems.

CT imaging analysis of the C7 pedicle and lateral mass in children aged 0–14 years

Background and objectiveThere is currently a lack of anatomical research on the C7 pedicle and lateral mass in children aged 0–14 years, and experience with pediatric lower cervical spine surgeries remains limited. This study aims to investigate the anatomical structure of the C7 pedicle and lateral mass in a large pediatric sample to understand their growth patterns, providing imaging and anatomical references for pediatric lower cervical spine surgeries and the design of pediatric C7 screws. MethodsWe measured 12 parameters, including the width, length, height, and angles of the C7 pedicle and lateral mass in children aged 0–14 years. The t-test was used to analyze bilateral and gender differences, and least squares regression was applied for curve fitting analysis. ResultsThe size parameters of the C7 pedicle and lateral mass generally increased with age, while angular parameters fluctuated within specific ranges. The average values for each parameter between ages 0–14 were as follows: D1: 2.78–5.28 mm, D2: 18.15–30.54 mm, D3: 2.44–6.01 mm, angle A: 38.05–44.48°; D4: 6.81–10.94 mm, D5: 5.37–11.23 mm, D6: 8.07–13.28 mm, D7: 1.94–4.88 mm, D8: 5.67–9.39 mm, angle C: 18.50–28.80°, angle D: 43.23–52.01°, angle E: 33.74–44.96°. Bilateral analysis showed no significant differences for most parameters across most age groups, with differences mainly observed in angle A, angle C, D6, and D8. Gender differences were primarily noted in length parameters across different age groups, especially in the 3–4, 6–7, 9–11, and 13–14 age groups. Regression analysis indicated that most parameters followed cubic function curves, while a few followed power or quadratic function curves. ConclusionThis study provides detailed CT imaging anatomy of the C7 pedicle and lateral mass in children aged 0–14 years. Preoperative thin-slice CT scans and careful measurements of key parameters are essential for pediatric lower cervical spine surgeries. The findings offer valuable imaging and anatomical references for pediatric posterior cervical fixation surgery and screw design.

Mapping 18F-FDG PET uptake in the aortic wall and thrombus

Abstract Background Positron Emission Tomography (PET) uptake allows for the assessment of molecular activity, being 18F-FDG uptake indicative of glucose metabolism. PET uptake is commonly quantified manually by drawing regions of interest, which is subjective, poorly-reproducible and may miss relevant information. Purpose To develop and test an image analysis method to quantify and map 18F-FDG uptake on the whole aortic wall and thrombus. Methods PET-MRI was acquired in patients with thoracic or abdominal aortic aneurysms. The aorta was semi-automatically segmented in the MR angiography using 3DSlicer, generating a surface mesh that was expanded by 3 mm inward and outward. PET uptake was interpolated over this volume with a uniform spatial resolution of 1 mm. By means of 9 reference points, the aortic wall was discretized into 52 (thoracic) or 80 (thoraco-abdominal) standardized regions (i.e. wall patches). For each aortic patch and for the whole thrombus volume, the target to background Ratio (TBR) was calculated by dividing the uptake by a reference uptake in the left atrium. Two observers segmented the aorta and thrombus, located the anatomical reference points and quantified TBR. Inter-observer agreement for segmentation and aortic wall discretization was evaluated in terms of the 95% Hausdorff Distance (HD) and Dice Score Coefficient (DSC), while both median and 95% TBR in each region were tested via intra-class correlation coefficient (absolute value, single measure). Results Data from 20 patients with thoracic or abdominal aneurysms were analysed, 10 of them presented thrombus. The reproducibility of the segmentation of the aorta (median HD 3.16 IQR [2.42 - 3.94] mm, DSC 0.90 [0.89 - 0.92]) and of the thrombus (HD 4.87 [3.51 - 8.45] mm, DSC 0.85 [0.80 - 0.87]) were excellent. The inter-observer agreement in the localization of reference points was good (HD 5.10 [3.29 - 8.73] mm), resulting in excellent overlapping of the standardized aortic wall patches (HD 3.80 [2.44 - 5.08] mm). Inter-observer agreement of median and 95% TBR in each aortic patch were excellent (ICC of 0.90 and 0.93, respectively, Figure 1), with minimal bias (Figure 2). Similarly, excellent interobserver reproducibility was observed for median and 95% TBR in the thrombus (ICC of 0.97 and 0.96, respectively, Figure 2). Conclusions A robust and reproducible image analysis method to map PET uptake along the aortic wall was developed, extending the possibilities to study aortic diseases molecular activity and its association with local aortic characteristics.

Origin and Course Cavernous Internal Carotid Artery Branches from the Endoscopic Endonasal Perspective: Cadaveric Study and Analysis Clinical Implications.

Endoscopic endonasal approaches to treat cavernous sinus lesions require detailed knowledge of the origin, course, and anatomic variations of the branches of the cavernous internal carotid artery (cICA) because inadvertent avulsion can cause intraoperative ICA injury. We aim to study the origin and course of the branches of the cICA from an endoscopic endonasal perspective and relate these branches to surgically relevant anatomic references. Sixty sides of 30 formalin-fixed specimens were dissected to identify the origin and course of cICA branches, including the inferolateral trunk (ILT), the meningohypophyseal trunk (MHT), anterior and inferior McConnell's capsular arteries (MCAs), and the superolateral trunk (SLT). The ILT and MHT were bilaterally in all specimens, whereas the anterior and inferior MCAs were identified in 28% and 25% of dissected sides, respectively. The SLT was only found in 3% of sides dissected. The MHT was the most proximal branch of the cICA, and its origin was an average of 8.9 mm anterior to the foramen lacerum and 3.8 mm superior to the sellar floor. The ILT was the second most proximal branch of the cICA, which originated 6.4 mm from the MHT on average. The anterior and inferior MCAs were present in 28% and 25% of specimens, respectively. The SLT, when present, was the second most proximal branch of the cICA, which originated at a mean height of 2.7 mm from the sellar floor. Overall, complete ILT and MHT were identified in 68% and 77% of cases, respectively. The MHT and ILT are constant branches of the cICA, with the MHT originating from the medial cICA posterior bend 4 mm superior to the sellar floor and 9 mm anterior to the foramen lacerum, whereas the ILT arises from the lateral horizontal cICA, 2.3 mm superior to the sellar floor and 6 mm anterior to the MHT.

Frequency-independent dual-tuned cable traps for multi-nuclear MRI and MRS

Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS) of non-proton nuclei (X-nuclei) typically require additional proton imaging for anatomical reference and B0 shimming. Therefore, two RF systems exist, necessitating cable traps to block the unwanted common-mode current at both Larmor frequencies of 1H and X-nuclei. This study introduces a frequency-independent dual-tuned cable trap that combines a standard solenoid cable trap with a float solenoid trap to independently tune high and low frequencies without compromising performance. The methods involved theoretical analysis, electromagnetic simulations, and bench tests. Two design approaches were evaluated: a float cable trap for 1H, a non-float cable trap for X-nuclei, and vice versa. Results showed that the design with the float trap for X-nuclei and non-float for 1H had superior performance, with high common-mode current suppression ability at both frequencies. Bench tests confirmed these findings, demonstrating effectiveness across various static fields and X-nuclei. The proposed frequency-independent dual-tuned cable trap provides a compact and efficient solution for multinuclear MRI and MRS, enhancing safety, image quality, and flexibility.

Novel Method of Measuring Pelvic Floor Muscle Motion May Improve Accessibility of Pelvic Floor Muscle Coordination Training.

Pelvic floor muscle ultrasound is an important clinical tool for improving motor coordination and even strength. Although the gold standard approach involves transperineal probe placement, this is not always feasible with sensitive populations, requires privacy owing to probe placement, and additional sonography training. This article introduces a novel transabdominal method for measuring pelvic floor muscle motion that incorporates a reference point within the bladder. The hypothesis is that the novel measurement will correlate positively with transperineal measurements. A total of 55 women (15 nulliparous, 40 parous; 20 continent, 35 incontinent) performed pelvic floor muscle contraction and strain. Transabdominal ultrasound measured bladder diagonal length (BDL) and transperineal ultrasound measured bladder neck height (BNH), levator plate length (LPL), and levator plate angle (LPA). Spearman's test measured the correlation between the measurement outcomes and an independent t test compared outcomes based on parity and stress urinary incontinence symptom status. Spearman's correlation showed moderate positive correlations between the pelvic floor measurements for both tasks, which reduced slightly when grouping by parity and symptom status. Group differences were significant for BDL during the muscle contraction, factoring in SUI symptoms (p = 0.019) and parity status (p = 0.005) and LPL during contraction, factoring in parity status (p = 0.033). BDL correlates with BNH, LPL, and LPA with slightly reduced correlation when factoring in parity and continence status. The advantages of the method include accessibility for sensitive populations, nontraditional positions due to the anatomical reference point, functional locations due to limited privacy needs, and minimal training required for pelvic floor therapists to incorporate into rehabilitation.

Microsurgical anatomy and the inner architecture of the retrocommissural portion of the hippocampal formation demonstrated through fiber microdissection.

An understanding of the complex nomenclature and 3D spatial relations between the cortical and white matter components of the retrocommissural portion of the hippocampal formation is essential for a successful outcome when performing surgery in the mediobasal temporal region. The goal of this study was to clarify the nomenclature related to the retrocommissural portion of the hippocampal formation and to provide a detailed description of its topography and inner structure from a relevant surgical perspective. This description can serve as an anatomical reference for approaching lesions in the mediobasal temporal region. Fiber microdissection was performed from the superolateral and inferior aspects on 20 previously frozen, formalin-fixed human brains. Three formalin-fixed plastinated brain specimens were then sectioned in the coronal, axial, and sagittal planes, and the relevant sections were studied. Based on its relationship with the corpus callosum, the hippocampal formation is subdivided into precommissural, supracommissural, and retrocommissural sections. The retrocommissural portion of the hippocampal formation, a structure in the mediobasal temporal region, is a component of both the floor of the temporal horn and the medial surface of the cerebral hemisphere. It includes the hippocampus (Ammon's horn and the dentate gyrus), subiculum, and related white matter fibers. Step-by-step microdissection revealed the complex ventricular and cisternal relationships of the retrocommissural portion of the hippocampal formation in the mediobasal temporal region. This further allowed clear distinction of each component of this formation in order to understand their complex reciprocal relationships that comprise a unique internal architecture and external morphology. The fiber microdissection technique provides a valuable perspective for understanding the complex structure and relations of the components of the retrocommissural portion of the hippocampal formation. This study clarifies and supplements the information presently available in the literature by offering an anatomical reference essential for differentiating the topographic diagnosis and safer surgical planning for any lesion within this formation or the mediobasal temporal region.

Efficacy of the Coronoid Notch and Occlusal Plane As Predictable Landmarks for Determining the Medial Cut Height in Bilateral Sagittal Split Osteotomy: A Split-Mouth Observational Study.

This split-mouth observational study was conducted to assess the reliability and safety of using the coronoid notch and occlusal plane as landmarks to aid surgeons during bilateral sagittal split osteotomy(BSSO). Thirteen patients between the ages of 18 and 30 years, with class II and class III mandibular skeletal malocclusion requiring BSSO, were randomly selected and assigned to each of the study and control groups. A split-mouth study was chosen to conduct this research. Cone beam computed tomography (CBCT) imaging was conducted before the surgery to evaluate the anatomical structure, and three predefined points were marked at the superiormost point of the mandibular foramen, the inferiormost point of the mandibular foramen, and the deepest point of the sigmoid notch. A conventional sagittal split osteotomy was carried out in the control group. Preoperative values were obtained in the study group using the CBCT imaging technique by drawing an imaginary line from the inferiormost part of the mandibular foramen to the line corresponding to the occlusal plane that extended beyond the last molar. The lingual flap reflection was restricted to the internal oblique ridge. The posterior border of the mandible was not reflected. The measurements acquired via CBCT imaging were accurately transferred to the intraoperative surgical site using a vernier caliper. This facilitated the precise completion of the horizontal osteotomy, ascending ramus cuts, and vertical osteotomies. BSSO was performed, the mandibular setback or advancement was done with intermaxillary fixation, and the procedure was completed by rigid fixation. Types of lingual splits, types of lateral bone cut ends (LBCEs), any unfavorable split, and the time taken for the surgery (in minutes) were assessed. The surgery time in the control group (20.1538 ± 2.85325 min) was found to be higher than that in the study group (17.6154 ± 3.59487 min), with a p-value of 0.02. No significant differences were observed when assessing the presence of unfavorable splits in both groups (p = 0.500). Buccal LBCEs were the most prevalent, followed by inferior types. Type I lingual split was the most common in the study group (70%). This technique offers a dependable anatomical reference and significantly reduces surgical time for beginners. Additionally, the patterns of the lingual split were correlated with the types of lateral bone cut ends.

Skink systematics inside out: Comparative cranial osteology of the New World Mabuyinae.

The Mabuyinae subfamily exhibits remarkable diversity, encompassing 26 genera and 236 currently recognized species. Traditionally, the entire range of the group was attributed to the single genus Mabuya, which had a wide distribution along tropical regions of the Planet. In recent studies, phylogenetic hypotheses based on molecular data have identified four major groups, which have been further divided into geographically distinct clades. At least two phylogenetically distinct lineages of Mabuyinae are distributed in the Neotropical Region: Trachylepis atlantica and the remaining 16 genera within the Mabuyinae clade from the mainland and the Caribbean islands. Our understanding of Mabuyinae osteology is still quite limited, particularly concerning interspecific variation. This lack of information hinders our ability to make strong contributions to the phylogenetic relationships within this group or even to confirm the existence of certain new taxa considering their relatively conserved external morphology. This work provides a comprehensive anatomical reference for the adult skull of Neotropical Mabuyinae lizards, highlighting osteological features that might be useful for delimiting each genus. This descriptive guide includes illustrations and employs multiple techniques, such as dry preparation, clearing and staining, and high-resolution computerized microtomography. Our results provide additional diagnostic characteristics that include specific cranial bone arrangements, dental patterns, and cranial adaptations, such as dorsoventral head flattening, and their functional implications for bite force and cranial biomechanics. This study reinforces the importance of cranial morphology in understanding the phylogenetic relationships and evolutionary trajectories of New World Mabuyinae lizards, advocating for broader morphological sampling to enrich our understanding of these diverse reptiles.

The embryotoxic and teratogenic effects of metamizole sodium.

Drug use during pregnancy is an important issue that must be investigated due to its adverse effects on maternal and foetal health. This study aimed to determine the embryotoxic and teratogenic effects of in-ovo administered metamizole (dipyrone), which can be used when needed during pregnancy and has potent analgesic, antipyretic, anti-inflammatory, and long bone (tibia and femur) effects. This study used 240 fertile eggs from Atak S breed chickens, divided into eight equal groups: control, vehicle control, and 15.62, 31.25, 62.5, 125, 250 and 500 mg/kg metamizole. The eggs were hatched on the 21st day of incubation, and the chicks' body weights and mortality rates were determined. The right and left femur and tibia bones were resected from the chicks. Anatomical reference points were determined after removing the soft tissues of the bones, and necessary morphometric measures were taken from these points with a 0.01 mm precision using digital callipers. The 100% lethal dose (LD100) was identified in the highest examined dose (500 mg/kg) in the Chicken Embryotoxicity Screening Test (CHEST)-I stage. The CHEST-II stage determined the 50% lethal dose (LD50). High-dose metamizole affected skeletal development, significantly decreasing tibia and femur lengths and corpus thicknesses and increasing mortality.

Morphological description of the temporomandibular joint ligaments in domestic pigs.

The temporomandibular joint (TMJ) ligaments play crucial roles in its function or dysfunction. The objective of this study was to describe the macro and microscopic morphology of these ligaments in domestic pigs, aiming to: (1) expand knowledge about the species; (2) provide anatomical references for advancing veterinary therapy and utilizing pigs as animal models in craniofacial research. Heads of young Sus scrofa domesticus were dissected to identify TMJ ligaments. Fragments of these ligaments were collected and processed for subsequent histological analysis with Haematoxylin and eosin staining. The results were qualitatively described. Pigs exhibited a TMJ reinforced by three individualized capsular ligaments: a lateral ligament, attaching to the ventral margin of the zygomatic process of the temporal bone and the lateral margin of the mandibular neck; a caudomedial ligament, attaching to the retroarticular process of the squamous part of the temporal bone and the caudomedial margin of the mandibular neck and a caudolateral ligament, attaching to the ventral margin of the base of the zygomatic process of the temporal bone and the caudal margin of the mandibular neck. The lateral ligament exhibited a greater constitution of dense irregular connective tissue, while the caudomedial and caudolateral ligaments showed a greater constitution of dense regular connective tissue. It is concluded that the TMJ of pigs presents one more ligament than horses, cattle, dogs, cats and what has been described for pigs themselves. We believe these results may contribute to the improvement of veterinary clinical and surgical therapy overall, as well as provide essential morphological information for a better interpretation and application of interspecies results in craniofacial research using pigs as an experimental model, as in the case of humans.

Selective neck dissection-the supraomohyoid, lateral, and anterolateral dissection techniques

In this article, the indications for performing the supraomohyoid, lateral, and anterolateral selective neck dissections will be discussed. Super selective neck dissections, though not included with a specific technique section, will also be briefly examined. An emphasis of the authors’ techniques will be illustrated with pertinent anatomy as well as post-operative care and complications to consider. Photographs will accompany the write-up in order to provide the reader with an anatomic operative reference.

Breast segmentation in infrared thermography from characteristical inframammary shape.

Infrared thermography is gaining relevance in breast cancer assessment. For this purpose, breast segmentation in thermograms is an important task for performing automatic image analysis and detecting possible temperature changes that indicate the presence of malignancy. However, it is not a simple task since the breast limit borders, especially the top borders, often have low contrast, making it difficult to isolate the breast area. Several algorithms have been proposed for breast segmentation, but these highly depend on the contrast at the lower breast borders and on filtering algorithms to remove false edges. This work focuses on taking advantage of the distinctive inframammary shape to simplify the definition of the lower breast border, regardless of the contrast level, which indeed also provides a strong anatomical reference to support the definition of the poorly marked upper boundary of the breasts, which has been one of the major challenges in the literature. In order to demonstrate viability of the proposed technique for an automatic breast segmentation, we applied it to a database with 180 thermograms and compared their results with those reported by others in the literature. We found that our approach achieved a high performance, in terms of Intersection over Union of 0.934, even higher than that reported by artificial intelligence algorithms. The performance is invariant to breast sizes and thermal contrast of the images.

Evaluation of anatomic variations in the posterior superior alveolar artery – A Cone-beam Computed Tomography (CBCT) study

Anatomical variation of the course of posterior superior alveolar artery (PSAA) within maxillary bone are vital information for surgeons before any maxillary surgery. This study was designed to evaluate the variations of PSAA by determining the prevalence of intraosseous PSAA and assessing the anatomical reference points and diameter of the PSAA. Comparison between dentate and edentulous alveolus was also done. One hundred CBCT images were included in this study to enumerate the prevalence of intraosseous PSAA in maxilla. Anatomical reference points which include the horizontal position of the PSAA and the vertical distance from the PSAA to the maxillary sinus floor and alveolar crest were identified. The diameter and horizontal position of PSAA were also analysed. The results were tested using independent t-test and chi square test. The PSAA was seen in 73.5% of the cases and 70.1% were located intraosseously. There was no significant difference in the vertical distance between PSAA and alveolar crest, as well as between maxillary sinus floor and alveolar crest for dentate and edentulous patients. Meanwhile, there was a significantly greater vertical distance between the PSAA and the maxillary sinus floor in edentulous (9.24 ± 4.75 mm) than in dentate patients (6.78 ± 3.43 mm) with p-value of 0.002. Mean diameter of the canal was 1.09 ± 0.43 mm. In conclusion, this study provides useful information regarding the most prevalent location and diameter of the PSAA which indicates the importance of preoperative evaluation through CBCT to reduce the risk of intraoperative bleeding that may complicate the treatment.

Assessment of Sports Concussion in Female Athletes: A Role for Neuroinformatics?

Over the past decade, the intricacies of sports-related concussions among female athletes have become readily apparent. Traditional clinical methods for diagnosing concussions suffer limitations when applied to female athletes, often failing to capture subtle changes in brain structure and function. Advanced neuroinformatics techniques and machine learning models have become invaluable assets in this endeavor. While these technologies have been extensively employed in understanding concussion in male athletes, there remains a significant gap in our comprehension of their effectiveness for female athletes. With its remarkable data analysis capacity, machine learning offers a promising avenue to bridge this deficit. By harnessing the power of machine learning, researchers can link observed phenotypic neuroimaging data to sex-specific biological mechanisms, unraveling the mysteries of concussions in female athletes. Furthermore, embedding methods within machine learning enable examining brain architecture and its alterations beyond the conventional anatomical reference frame. In turn, allows researchers to gain deeper insights into the dynamics of concussions, treatment responses, and recovery processes. This paper endeavors to address the crucial issue of sex differences in multimodal neuroimaging experimental design and machine learning approaches within female athlete populations, ultimately ensuring that they receive the tailored care they require when facing the challenges of concussions. Through better data integration, feature identification, knowledge representation, validation, etc., neuroinformaticists, are ideally suited to bring clarity, context, and explainabilty to the study of sports-related head injuries in males and in females, and helping to define recovery.

New Ultrasound-Guided Approach to Access to the Posterolateral Part of Intervertebral Lumbar Discs: A Cadaveric Study.

Background: Approximately 40% of chronic low back pain patients have a discogenic origin. In relation to intervertebral disc injuries, most of them are in the posterior and lateral zone of the disc, involving the anterior lumbar roots and the spinal cord. Objective: The objective was to analyze and describe the accuracy and safety of a new ultrasound-guided approach to target the posterolateral part of the intervertebral lumbar discs in cadaveric specimens. Methods: A cross-anatomical study on sixty cadaver intervertebral lumbar discs was performed. A needle was introduced in the posterolateral part of the discs using ultrasound guidance. A transducer was placed in the anterior abdomen to visualize the discs in cross-section as well. A dissection of the specimen was performed to visualize the final position of the needle tip and its distance from the main lumbar structures. The angulation, length, and distance of the needle from the vertebral spine, the relevant ultrasound anatomical references, and the accuracy of the procedure were evaluated. Results: The needle tip reached the posterolateral part of the discs in 93.3% of the attempts. The mean length of the needle inserted was 79 ± 15 mm, the angulation 129 ± 20.2°, the distance from the spinous process was 77 ± 19 mm, and the distance of the needle to the nerve roots was 2.0 ± 1.2 mm. No statistically significant differences between genders were found. Conclusions: An ultrasound-guided technique can be an accurate and safe technique to perform invasive procedures on the posterolateral part of the intervertebral lumbar discs.

Computer-Assisted Implant Planning: A Review of Data Registration Techniques.

Computer-assisted implant planning allows for a comprehensive treatment plan by combining radiographic data provided by a Cone Beam Computed Tomography (CBCT) with surface optical scan (IOs) data that includes patient intraoral situation and the intended restorative planning. Integrating a tailored restorative design with the patient's anatomical conditions through virtual implant planning allows for an ideal bio-restorative treatment planning to maximize biological, functional, and esthetic outcomes. This article discusses dataset registration techniques that combine radiographic CBCT data with restorative information as the main path to create a virtual patient. The described techniques include the use of removable radiographic templates with radiopaque markers, dual scan technique, and direct digital file registration of intra-oral scans using anatomical references. Depending on the individual clinical situation, different factors must be considered to appropriately select methods that achieve an optimal registration of diverse datasets. An inherent challenge lies in the presence of scattering artifacts in CBCT scans. Two approaches are proposed for these situations - the use of chairside-fabricated composite resin markers or adhesive spot-markers fabricated for the use with CBCT scans. Both techniques exhibit limitations that need to be taken into consideration. Further approaches should be developed for situations involving scattering in CBCT.

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

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. 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. 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°. 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.

Temporal Changes on Postgadolinium MR Vessel Wall Imaging Captures Enhancement Kinetics of Intracranial Atherosclerotic Plaques and Aneurysms.

Analysis of vessel wall contrast kinetics (ie, wash-in/washout) is a promising method for the diagnosis and risk-stratification of intracranial atherosclerotic disease plaque (ICAD-P) and the intracranial aneurysm walls (IA-W). We used black-blood MR imaging or MR vessel wall imaging to evaluate the temporal relationship of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws compared with normal anatomic reference structures. Patients with ICAD-Ps or IAs who underwent MR vessel wall imaging with precontrast, early postcontrast (5-15 minutes), and delayed postcontrast (20-30 minutes) 3D T1-weighted TSE sequences were retrospectively studied. ROIs of a standardized diameter (2 mm) were used to measure the signal intensities of the cavernous sinus, pituitary infundibulum, temporalis muscle, and choroid plexus. Point ROIs were used for ICAD-Ps and IA-Ws. All ROI signal intensities were normalized to white matter signal intensity obtained using ROIs of 10-mm diameter. Measurements were acquired on precontrast, early postcontrast, and delayed postcontrast 3D T1 TSE sequences for each patient.ajnr;45/9/1206/T1T1T1Table 1:MR-VWI parameters for ICAD-Ps and IAsParameterValueSequence3D TSEScan planeAxialFOV (mm)160TR/TE (ms)800/28-32BW (Hx/pixel)370θ120Acceleration2ETL42Matrix acquisition0.5 mm ×0.5 mmMatrix recon0.5 mm ×0.5 mmNo. of slices/thick120/0.5Note:-FOV indicates field of view; TR, the repetition time; TE, the echo time; BW, bandwidth; ETL, echo train length; Matrix recon, matrix reconstruction. Ten patients with 17 symptomatic ICAD-Ps and 30 patients with 34 IA-Ws were included and demonstrated persisting contrast uptake (P < .001) of 7.21% and 10.54% beyond the early phase (5-15 minutes postcontrast) and in the delayed phase (20-30 minutes postcontrast) on postcontrast MR vessel wall imaging. However, normal anatomic reference structures including the pituitary infundibulum and cavernous sinus demonstrated a paradoxical contrast washout in the delayed phase. In both ICAD-Ps and IA-Ws, the greatest percentage of quantitative enhancement (>70%-90%) occurred in the early phase of postcontrast imaging, consistent with the rapid contrast uptake kinetics of neurovascular pathology. Using standard MR vessel wall imaging techniques, our results demonstrate the effects of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws with extended accumulating enhancement into the delayed phase (> 15 minutes) as opposed to normal anatomic reference structures that conversely exhibit decreasing enhancement. Because these relative differences are used to assess qualitative patterns of ICAD-P and IA-W enhancement, our findings highlight the importance of standardizing acquisition time points and MR vessel wall imaging protocols to interpret pathologic enhancement for the risk stratification of cerebrovascular pathologies.