Measurements Of Anatomical Structures Research Articles

Investigating Transducer–Tissue Interface Pressure for Soft Tissue Stress–Strain Behavior and the Effects on Echoic Intensities in Ultrasound Imaging of Periodontium

AbstractDiagnostic ultrasound (US) is a major imaging modality to visualize soft tissues and blood flow with the advantages of real‐time imaging, high acceptability to patients, and absence of ionizing radiation. US imaging provides important clinical measurements, e.g., thickness of gingiva for treatment planning in orthodontics, periodontics, and implantology; or thickness of subcutaneous adipose for optimizing insulin injection. However, the image quality and measurements of anatomical structures can be inconsistent, i.e., due to varying pressure exerted by an US transducer. Herein, a simple device is developed to real‐time measure the interface pressure applied on tissues by the US transducer. A thin‐film piezo‐resistive sensor with a small footprint is integrated to sense the pressure. A theoretical model, based on hyperelastic material behavior, is verified using the pressure measured by the thin film sensor and the thickness determined on ultrasonograms. The device is also tested on porcine samples in the pressure range of 50–300 kPa for imaging gingiva boundaries, identifying tissue thickness, and probing tissue biomenchanical properties. The device enables the understanding on the optimal range of applied pressure for higher contrast imaging. The information of the on‐tissue pressure and the tissue deformation determined on the US images help to derive the biomechanical stress–strain behavior of the tissues.

Value of three-dimensional visualization of preoperative prostatic magnetic resonance imaging based on measurements of anatomical structures in predicting positive surgical margin after radical prostatectomy.

Positive surgical margin (PSM) or apical positive surgical margin (APSM) is an established predictive factor of biochemical recurrence or disease progression in prostate cancer (PCa) patients after radical prostatectomy. Since there are limited usable magnetic resonance imaging (MRI)-based models, we sought to explore the role of three-dimensional (3D) visualization for preoperative MRI in the prediction of PSM or APSM. From December 2016 to April 2022, 149 consecutive PCa patients who underwent radical prostatectomy were retrospectively selected from the Second Affiliated Hospital of Dalian Medical University. According to the presence of PSM or APSM, patients were divided into a PSM group (n=41) and a without PSM group (n=108) and into an APSM group (n=33) and a without APSM group (n=116). Twenty-one parameters, including prostate apical shape, PCa distance to the membranous urethra, and pubic angle, were measured on 3D visualization of MRI. The development of the nomogram models was built by the findings of multivariate logistic regression analysis for significant factors. To predict the probability of PSM, a longer PCa distance to the membranous urethra (OR=0.136, p=0.019) and the distance from the anterior peritoneum to the anterior border of the coccyx (work space AP, OR=0.240, p=0.030) were independent protective factors, while a type 3 prostate apical shape (OR=8.262, p=0.025) and larger pubic angle 2 (OR=5.303, p=0.029) were identified as independent risk factors. The nomogram model presented an area under the curve (AUC) of the receiver operating characteristic curve (ROC) of PSM of 0.777. In evaluating the incidence of APSM, we found that the distance to the membranous urethra (OR=0.135, p=0.014) was associated with a low risk of APSM, while larger pubic angle 1 (OR=4.666, p=0.043) was connected to a higher risk of APSM. The nomogram model showed that the AUC of APSM was 0.755. As 3D visualization for preoperative MRI showed good performance in predicting PSM or APSM, the tool might be potentially valuable, which also needs to be validated by multicenter, large-scale, prospective studies.

ANATOMICAL, PALYNOLOGICAL AND MICROMOPHOLOGICAL INVESTIGATIONS ON ENDEMIC THYMUS BRACHYCHILUS JALAS (LAMIACEAE)

Objective: In this study, it was aimed to investigate the anatomical and palynological features of endemic Thymus brachychilus Jalas. Material and Method: The plant material was fixed in 70% alcohol for anatomical investigation. Cross sections of the stem, leaves, and leaf surface sections were stained with sartur solution, and the anatomical aspects were examined. The trichome architectures, mesophyll cells, stomatal index, and glandular and non-glandular trichomes features of leaves and stem have been investigated and compared with the other Thymus species anatomical findings. In addition, measurements of anatomical structures were made. Pollen, flower parts, epidermis and trichome structure of the leaves, were examined in SEM. Result and Discussion: This is the first anatomical, palynological and micromorphological study on Thymus brachychilus. The epidermis of leaf consists of a single row of elongated shaped cells and is covered with a thin cuticle. There are nonglandular and glandular trichomes in the upper and lower epidermis. Two different types of nonglandular trichomes were found. Stomata are diacytic, and the epidermis is amphistomatic. The mesophyll layer is dorsiventral. The stem cross-section is square. The outermost single-row, elongated, square or rectangular epidermis is covered with a thin cuticle. The pollen symmetry is isopolar, shape is suboblate. It has hexacolpate and bireticulate properties.

Automated segmentation and measurement of the female pelvic floor from the mid-sagittal plane of 3D ultrasound volumes.

Transperineal ultrasound (TPUS) is a valuable imaging tool for evaluating patients with pelvic floor disorders, including pelvic organ prolapse (POP). Currently, measurements of anatomical structures in the mid-sagittal plane of 2D and 3D US volumes are obtained manually, which is time-consuming, has high intra-rater variability, and requires an expert in pelvic floor US interpretation. Manual segmentation and biometric measurement can take 15 min per 2D mid-sagittal image by an expert operator. An automated segmentation method would provide quantitative data relevant to pelvic floor disorders and improve the efficiency and reproducibility of segmentation-based biometric methods. Develop a fast, reproducible, and automated method of acquiring biometric measurements and organ segmentations from the mid-sagittal plane of female 3D TPUS volumes. Our method used a nnU-Net segmentation model to segment the pubis symphysis, urethra, bladder, rectum, rectal ampulla, and anorectal angle in the mid-sagittal plane of female 3D TPUS volumes. We developed an algorithm to extract relevant biometrics from the segmentations. Our dataset included 248 3D TPUS volumes, 126/122 rest/Valsalva split, from 135 patients. System performance was assessed by comparing the automated results with manual ground truth data using the Dice similarity coefficient (DSC) and average absolute difference (AD). Intra-class correlation coefficient (ICC) and time difference were used to compare reproducibility and efficiency between manual and automated methods respectively. High ICC, low AD and reduction in time indicated an accurate and reliable automated system, making TPUS an efficient alternative for POP assessment. Paired t-test and non-parametric Wilcoxon signed-rank test were conducted, with p<0.05 determining significance. The nnU-Net segmentation model reported average DSC and p values (in brackets), compared to the next best tested model, of 87.4% (<0.0001), 68.5% (<0.0001), 61.0% (0.1), 54.6% (0.04), 49.2% (<0.0001) and 33.7% (0.02) for bladder, rectum, urethra, pubic symphysis, anorectal angle, and rectal ampulla respectively. The average ADs for the bladder neck position, bladder descent, rectal ampulla descent and retrovesical angle were 3.2mm, 4.5mm, 5.3mm and 27.3°, respectively. The biometric algorithm had an ICC>0.80 for the bladder neck position, bladder descent and rectal ampulla descent when compared to manual measurements, indicating high reproducibility. The proposed algorithms required approximately 1.27 s to analyze one image. The manual ground truths were performed by a single expert operator. In addition, due to high operator dependency for TPUS image collection, we would need to pursue further studies with images collected from multiple operators. Based on our search in scientific databases (i.e., Web of Science, IEEE Xplore Digital Library, Elsevier ScienceDirect and PubMed), this is the first reported work of an automated segmentation and biometric measurement system for the mid-sagittal plane of 3D TPUS volumes. The proposed algorithm pipeline can improve the efficiency (1.27 s compared to 15 min manually) and has high reproducibility (high ICC values) compared to manual TPUS analysis for pelvic floor disorder diagnosis. Further studies are needed to verify this system's viability using multiple TPUS operators and multiple experts for performing manual segmentation and extracting biometrics from the images.

Functional relationship between the anatomical structures of the calf and athletic ability.

Calf muscle plays an important function in driving the movement of stepping on the ground and moving forward when walking or running. The Achilles tendon has been reported to be closely related to the elasticity of tendons to absorb shock and rebound and convert energy into propulsion. We wanted to determine the effect and correlation of the anatomical structure of the calf region on function. Measurements of anatomical structures were conducted with 51 volunteers using ultrasonography, and exercise capacity tests were conducted to measure anaerobic power, elasticity, and flexibility. The mean power and length of the calf (LoC), muscle thickness (MT), and fascicle angle (FA) of the medial head of gastrocnemius (p < 0.001) showed the strongest positive correlation among the variables of anatomical structures. MT of the Gastrocnemius and LoC Gastrocnemius were also correlated with peak power. In the anatomical structure variables, the FA of the lateral head of gastrocnemius, length and width of the Achilles tendon, and part of the athletic ability, the standing long jump test and sitting trunk flexion test, were not significantly correlated. Based on these results, it can be concluded that the height and degree of development of the calf muscles are structures that affect the exercise of anaerobic power. Hence, it can be used as a predictor of athletic ability. Furthermore, the trainer can predict athletic ability according to the characteristics of the event by first understanding the athlete's physical condition.

Quantitative Anatomical Characteristics of the Leaf Blades of the Several Species of &lt;i&gt;Crataegus&lt;/i&gt; L.

Introduction. The Crataegus L. (Hawthorn) is a common herb in numerous Pharmacopoeias. The State Pharmacopoeia of the Russian Federation provides hawthorn fruits and flowers for medical utilization. With that, the literature data confirms the medical utility of hawthorn leaves since the “leaves” and the “flowers with leaves” have pharmacopoeial status worldwide. Therefore, those are considered as prospective forms of Crataegus raw material for Russian pharmaceutical production. However, most species remain poorly pharmacognostically investigated regarding the quantitative microscopic characteristics (the sizes of stomatal apparatus (SA) and epidermal leaf blade (LB) trichomes), which could be substantial for establishing the authenticity of the raw material.Aim.Examine epidermal anatomy of Crataegus spp. Leaf blades (LBs) and perform a comparative study of several quantitative diagnostic features of LBs of hawthorn plants from the sect. Sanguineae and the sect. Crataegus, growing in diverse regions of the Russian Federation.Materials and methods. Samples of hawthorn leaves (C. sanguinea, C. maximowiczii, C. dahurica, C. rhipidophylla, C. monogyna and C. pallasii) were collected in natural habitats in Western Siberia (Kemerovo) and in arboretums of Botanical Gardens (Moscow, Stavropol). Measurements of anatomical structures were carried out using a light microscope accompanied by an ocular micrometre.Results and discussion.The LB surface phenotypic diversity within hawthorn species and sections was studied. The LBs were described in terms of meterages (longitude and width) of SA, meterages and shape of sedentary multicellular leaf teeth glands. The peculiarities of pubescence and the sizes of simple unicellular non-glandular trichomes were also observed.Conclusion. The results of quantitative anatomical examination provided the characteristic features determining these elements at the species and section levels. Thus, it may facilitate authentication and quality control of whole or ground Crataegus medicinal raw material.

A novel approach quantifying the periorbital morphology: A comparison of direct, 2-dimensional, and 3-dimensional technologies

The measurement of anatomical structures is critical in plastic and reconstructive surgery. However, few detailed and standardized measurements have been widely used in the periorbital region. This study aimed to evaluate the feasibility of a novel detailed and standardized protocol with 2D and 3D technologies, and explore the relationship between them and direct measurements. Fifty healthy Caucasians (100 eyes) between 20 and 68 years old were recruited and captured for 3D photographs by VECTRA M3 3D Imaging System. Subsequently, 24 landmarks were located on each 3D photographs following a standardized protocol, and then 19 linear and 3 angular periorbital variables were measured. Furthermore, two-dimensional (2D) and direct measurements were conducted on each subject and compared with 3D measurements and one another. The grand r means across all measurements were 0.77, 0.78, and 0.88 for direct vs. 2D values, direct vs. 3D values, and 3D vs. 2D values, respectively. The mean absolute differences were 1 mm (ranging from 0.2 mm to 3.7 mm) between direct and 3D measurements, 1 mm (ranging from 0.04 mm to 2.4 mm) between direct and 2D measurements, and 1 mm and 6.6° (ranging from 0.04 mm or 0.5° to 3 mm or 12.8°) between 2D and 3D measurements. This study verified the feasibility of this detailed and standardized landmark localization protocol for assessing the periorbital morphology with 2D and 3D technologies. This protocol may work as a bridge communicating with all studies involving any of the three technologies in the future.

Automated measurement network for accurate segmentation and parameter modification in fetal head ultrasound images.

Measurement of anatomical structures from ultrasound images requires the expertise of experienced clinicians. Moreover, there are artificial factors that make an automatic measurement complicated. In this paper, we aim to present a novel end-to-end deep learning network to automatically measure the fetal head circumference (HC), biparietal diameter (BPD), and occipitofrontal diameter (OFD) length from 2D ultrasound images. Fully convolutional neural networks (FCNNs) have shown significant improvement in natural image segmentation. Therefore, to overcome the potential difficulties in automated segmentation, we present a novelty FCNN and add a regression branch for predicting OFD and BPD in parallel. In the segmentation branch, a feature pyramid inside our network is built from low-level feature layers for a variety of fetal head in ultrasound images, which is different from traditional feature pyramid building methods. In order to select the most useful scale and reduce scale noise, attention mechanism is taken for the feature's filter. In the regression branch, for the accurate estimation of OFD and BPD length, a new region of interest (ROI) pooling layer is proposed to extract the elliptic feature map. We also evaluate the performance of our method on large dataset: HC18. Our experimental results show that our method can achieve better performance than the existing fetal head measurement methods. Graphical Abstract Deep Neural Network for Fetal Head Measurement.

Morphometric Evaluation of Craniocervical Junction by Magnetic Resonance Imaging Method.

Purpose:Morphometric evaluation of the craniocervical region using magnetic resonance imaging method in humans and determination of the reference values that could be used in various clinics were the aims of this study.Materials and Methods:In our study, 306 (95 males and 211 females) individuals who met the necessary criteria for anatomical structure were included and taken measurements afterward. Sagittal T1- and T2-weighted images were determined as a section thickness of 3 mm, an interval of 10 mm, a matrix of 352 × 224, a field of view of 170–240 mm, and a number of excitations of 4. Measurements of anatomical structures in the craniocervical region were taken via these images.Results:Statistically significant differences were found among the findings of male and female individuals such as height of dens axis, anteroposterior distance of the dens axis (APDDA), anterosuperior distance of the dens axis (ASDDA), sagittal diameter of the foramen magnum (SDFM), total cervical vertebra length (TCVL), distance of spatium retropharyngeum, Pavlov ratio, and the ratio between sagittal diameter of canalis vertebralis (SDCV) to the APDDA. Dens axis height showed a positive correlation with ASDDA and TCVL, and a negative correlation was found between the APDDA and the spatium retropharyngeum.Conclusion:Age- and sex-related changes in the measurements of anatomical regions reveal that an increase and a decrease in the various parameters reveal that these are the normal changes presumably determined by the functional and physical demands varying on the columna vertebralis.

Key anatomical landmarks for middle fossa surgery: a surgical anatomy study.

OBJECTIVEMiddle fossa surgery is challenging, and reliable surgical landmarks are essential to perform accurate and safe surgery. Although many descriptions of the middle fossa components have been published, a clinically practical description of this very complex anatomical region is lacking. Small structure arrangements in this area are often not well visualized or accurately demarcated with neuronavigation systems. The objective is to describe a "roadmap" of key surgical reference points and landmarks during middle fossa surgery to help the surgeon predict where critical structures will be located.METHODSThe authors studied 40 dry skulls (80 sides) obtained from the anatomical board at their institution. Measurements of anatomical structures in the middle fossa were made with a digital caliper and a protractor, taking as reference the middle point of the external auditory canal (MEAC). The results were statistically analyzed.RESULTSThe petrous part of the temporal bone was found at a mean of 16 mm anterior and 24 mm posterior to the MEAC. In 87% and 99% of the sides, the foramen ovale and foramen spinosum, respectively, were encountered deep to the zygomatic root. The posterior aspect of the greater superficial petrosal nerve (GSPN) groove was a mean of 6 mm anterior and 25 mm medial to the MEAC, nearly parallel to the petrous ridge. The main axis of the IAC projected to the root of the zygoma in all cases. The internal auditory canal (IAC) porus was found 5.5 mm lateral and 4.5 mm deep to the lateral aspect of the trigeminal impression along the petrous ridge (mean measurement values). A projection from this point to the middle aspect of the root of the zygoma, being posterior to the GSPN groove, could estimate the orientation of the IAC.CONCLUSIONSIn middle fossa approaches, the external acoustic canal is a reliable reference before skin incision, whereas the zygomatic root becomes important after the skin incision. Deep structures can be related to these 2 anatomical structures. An easy method to predict the location of the IAC in surgery is described. Careful study of the preoperative imaging is essential to adapt this knowledge to the individual anatomy of the patient.

Oblique popliteal ligament – an anatomical study

ObjectiveTo study the anatomy of the oblique popliteal ligament, as regards its dimensions, expansion and anatomical relationships. MethodsEleven cadaver knees were dissected in order to study the anatomy and take measurements of anatomical structures and relationships of the oblique popliteal ligament. The dissection was for posterior access to the proper exposure of the oblique popliteal ligament, the semimembranosus muscle and its expansions. For measurement of dimensions, 40×12 needles were used for marking the specific points and a caliper. The angles were calculated using the software ImagePro Plus®. ResultsThe distance from the origin of the oblique popliteal ligament to the tibial plateau was 7.4mm, the thickness at its origin was 7.3mm, length was 33.6mm and the tibial plateau angle 34.8°. The length of the expansion of the proximal oblique popliteal ligament was 39.2mm, thickness 7.8mm and angle of the oblique popliteal ligament with its expansion 32.2°. ConclusionThe oblique popliteal ligament is thick, rises in the semimembranosus and protrudes proximally forming an acute angle with the joint interline, crossing the popliteal fossa. In some cases it has a proximal expansion.

Assessment and Validation of a Methodology for Measuring Anatomical Kinematics of Restrained Occupants During Motor Vehicle Collisions

Efforts to improve restraint design for human occupant protection require a detailed knowledge of human kinematic response. However, to improve the current understanding of human kinematic response to restraint loading it is necessary to obtain a more detailed knowledge of how structures within the body such as individual ribs and vertebrae move during an impact event. Video-based optoelectronic stereo photogrammetric systems (OSS) have recently been employed for kinematic measurement during simulated vehicle collisions with restrained post mortem human surrogates (PMHS). Application of this methodology requires specialized optical sensor hardware to be surgically attached to anatomical structures of interest such as acromia, ribs orvertebrae. The hardware supports retro reflective spherical targets which are visible to the OSS. The recorded target motions are then transformed to the underlying anatomical structures to quantify the trajectories of individual bone centers throughout the impact event. This study presents the results of seven tests that were conducted to practically assess the efficacy of this emerging methodology for measuring anatomical kinematics during impact loading. The tests used a 16-camera 1000Hz OSS and a single simulated anatomical structure with attached target hardware to quantify the uncertainty in the calculated trajectory of the bone center. Specifically, the tests assessed the intrinsic optical error associated with the OSS, and also evaluated the ability of the rigid body transformation to reproduce a directly measured bone center trajectory. The tests also assessed the effect of compliance in the assumed rigid connection between the visible target hardware and underlying bone on the transformed trajectories. The results demonstrate robust performance of a novel methodology combining state-of-the-art optoelectronic technology, specialized target hardware, and rigid body transformation to obtain kinematic measurements of anatomical structures within the human body which are not visible or accessible for direct measurement during an impact event

Virtual Tape Measure for the Operating Microscope: System Specifications and Performance Evaluation

Objective: The Virtual Tape Measure for the Operating Microscope (VTMOM) was created to assist surgeons in making accurate 3D measurements of anatomical structures seen in the surgical field under the operating microscope. The VTMOM employs augmented reality techniques by combining stereoscopic video images with stereoscopic computer graphics, and functions by reiving on an operator's ability to align a 3D graphic pointer, which serves as the end-point of the virtual tape measure, with designated locations on the anatomical structure being measured. The VTMOM was evaluated for its baseline and application performances as well as its application efficacy.Methods: Baseline performance was determined by measuring the mean error (bias) and standard deviation of error (imprecision) in measurements of non-anatomical objects. Application performance was determined by comparing the error in measuring the dimensions of aneurysm models with and without the VTMOM. Application efficacy was determined by comparing the error in selecting the appropriate aneurysm clip size with and without the VTMOM.Results: Baseline performance indicated a bias of 0.3 mm and an imprecision of 0.6 mm. Application bias was 3.8 mm and imprecision was 2.8 mm for aneurysm diameter. The VTMOM did not improve aneurysm clip size selection accuracy.Discussion and Conclusion: The VTMOM is a potentially accurate tool for use under the operating microscope. However, its performance when measuring anatomical objects is highly dependent on complex visual features of the object surfaces.