Segmentation of 71 Anatomical Structures Necessary for the Evaluation of Guideline-Conforming Clinical Target Volumes in Head and Neck Cancers

The delineation of the clinical target volumes (CTVs) for radiation therapy is time-consuming, requires intensive training and shows high inter-observer variability. Supervised deep-learning methods depend heavily on consistent training data; thus, State-of-the-Art research focuses on making CTV labels more homogeneous and strictly bounding them to current standards. International consensus expert guidelines standardize CTV delineation by conditioning the extension of the clinical target volume on the surrounding anatomical structures. Training strategies that directly follow the construction rules given in the expert guidelines or the possibility of quantifying the conformance of manually drawn contours to the guidelines are still missing. Seventy-one anatomical structures that are relevant to CTV delineation in head- and neck-cancer patients, according to the expert guidelines, were segmented on 104 computed tomography scans, to assess the possibility of automating their segmentation by State-of-the-Art deep learning methods. All 71 anatomical structures were subdivided into three subsets of non-overlapping structures, and a 3D nnU-Net model with five-fold cross-validation was trained for each subset, to automatically segment the structures on planning computed tomography scans. We report the DICE, Hausdorff distance and surface DICE for 71 + 5 anatomical structures, for most of which no previous segmentation accuracies have been reported. For those structures for which prediction values have been reported, our segmentation accuracy matched or exceeded the reported values. The predictions from our models were always better than those predicted by the TotalSegmentator. The sDICE with 2 mm margin was larger than 80% for almost all the structures. Individual structures with decreased segmentation accuracy are analyzed and discussed with respect to their impact on the CTV delineation following the expert guidelines. No deviation is expected to affect the rule-based automation of the CTV delineation.

Morphologic, morphometric and contour shape variations of sagittal otoliths of Lepidorhombus spp. in the Aegean Sea

Otoliths are calcareous anatomical structures in the inner ear of fishes, and they can be used in the discrimination of fish species and stocks due to their species-specific shape. Sagittal otoliths in the Lepidorhombus whiffiagonis and Lepidorhombus boscii, two flatfish species of the same genus distributed in the Aegean Sea, were compared using morphology, morphometry and contour shape analyses. Blind and eyed side otoliths of Lepidorhombus species were evaluated separately due to their morphological features and statistical differences in morphometric measurements (p < 0.05). Four analysis groups were formed: blind side otolith of L. whiffiagonis, eyed side otolith of L. whiffiagonis, blind side otolith of L. boscii and eyed side otolith of L. boscii. Morphometric differences in otolith shape were performed by canonical discriminant analysis, and the first discriminant axis explained 97.4% (Wilks λ = 0.270) of the variance between the groups, and the second axis explained 2.3% (Wilks λ = 0.620). Classification success between Lepidorhombus species based on CDA is 100%, and the overall CDA classification score between groups is 76.5%. The wavelet functions obtained in the contour analysis showed high variability in the anterior, posterior-dorsal, antero-dorsal and ventral regions of the otoliths among these four analysis groups. Consequently, it is thought that this study will contribute to the taxonomic classification of fish with the morphological and morphometric differences in the blind and eyed side otoliths and the analyses made with the high discrimination success obtained in Lepidorhombus species.

What are the resection accuracy and guide-fitting errors associated with 3D-printed, patient-specific resection guides for bone tumour resections?

AIMS

This study aimed to analyze the accuracy and errors associated with 3D-printed, patient-specific resection guides (3DP-PSRGs) used for bone tumour resection.

METHODS

We retrospectively reviewed 29 bone tumour resections that used 3DP-PSRGs based on 3D CT and 3D MRI. We evaluated the resection amount errors and resection margin errors relative to the preoperative plans. Guide-fitting errors and guide distortion were evaluated intraoperatively and one month postoperatively, respectively. We categorized each of these error types into three grades (grade 1, < 1 mm; grade 2, 1 to 3 mm; and grade 3, > 3 mm) to evaluate the overall accuracy.

RESULTS

The maximum resection amount error was 2 mm. Out of 29 resection amount errors, 15 (51.7%) were grade 1 errors and 14 (38.3%) were grade 2 errors. Complex resections were associated with higher-grade resection amount errors (p < 0.001). The actual resection margins correlated significantly with the planned margins; however, there were some discrepancies. The maximum guide-fitting error was 3 mm. There were 22 (75.9%), five (17.2%), and two (6.9%) grade 1, 2, and 3 guide-fitting errors, respectively. There was no significant association between complex resection and fitting error grades. The guide distortion after one month in all patients was rated as grade 1.

CONCLUSION

In terms of the accurate resection amount according to the preoperative planning, 3DP-PSRGs can be a viable option for bone tumour resection. However, 3DP-PSRG use may be associated with resection margin length discrepancies relative to the planned margins. Such discrepancies should be considered when determining surgical margins. Therefore, a thorough evaluation of the preoperative imaging and surgical planning is still required, even if 3DP-PSRGs are to be used.Cite this article: Bone Joint J 2023;105-B(2):190-197.

Deep Learning-Based Medical Images Segmentation of Musculoskeletal Anatomical Structures: A Survey of Bottlenecks and Strategies

By leveraging the recent development of artificial intelligence algorithms, several medical sectors have benefited from using automatic segmentation tools from bioimaging to segment anatomical structures. Segmentation of the musculoskeletal system is key for studying alterations in anatomical tissue and supporting medical interventions. The clinical use of such tools requires an understanding of the proper method for interpreting data and evaluating their performance. The current systematic review aims to present the common bottlenecks for musculoskeletal structures analysis (e.g., small sample size, data inhomogeneity) and the related strategies utilized by different authors. A search was performed using the PUBMED database with the following keywords: deep learning, musculoskeletal system, segmentation. A total of 140 articles published up until February 2022 were obtained and analyzed according to the PRISMA framework in terms of anatomical structures, bioimaging techniques, pre/post-processing operations, training/validation/testing subset creation, network architecture, loss functions, performance indicators and so on. Several common trends emerged from this survey; however, the different methods need to be compared and discussed based on each specific case study (anatomical region, medical imaging acquisition setting, study population, etc.). These findings can be used to guide clinicians (as end users) to better understand the potential benefits and limitations of these tools.

Effects of NaCl Stress on the Growth, Physiological Characteristics and Anatomical Structures of Populus talassica × Populus euphratica Seedlings

In order to elucidate the salt tolerance mechanism of Populus talassica × Populus euphratica, the growth, physiology and anatomical characteristics of P. talassica × P. euphratica were studied under different concentrations of NaCl-stress treatments. In this study, the annual seedlings of Populus talassica × Populus euphratica were used as the test material in a field potted control experiment. The basic salt content of the culture soil was the control (CK), and two NaCl treatments of 200 mmol/L and 400 mmol/L were established. The pot experiment showed that: (1) Compared with CK, the 200 mmol/L NaCl-stress treatment significantly increased the growth parameters of P. talassica × P. euphratica, such as leaf area, plant height, ground diameter, biomass, root length, root surface area, root fork number and root-shoot ratio. However, compared with CK, the 400 mmol/L NaCl-stress treatment significantly reduced most growth parameters. (2) The 200 and 400 mmol/L NaCl-stress treatments significantly decreased various physiological parameters such as relative water content (RWC), chlorophyll content, water potential, stomatal opening and photosynthetic parameters and increased the accumulation of MDA and Pro compared with CK. The 200 mmol/L NaCl-stress treatment significantly increased the activity of antioxidant enzymes, and the 400 mmol/L NaCl-stress treatment significantly decreased the activity of antioxidant enzymes. (3) Compared with CK, 200 and 400 mmol/L NaCl-stress treatments significantly improved the leaf palisade tissue thickness and palisade-to-sea ratio, as well as the stem xylem and stem phloem thickness and pith diameter, and significantly increased the root xylem thickness, root phloem thickness, and root cross-cutting diameter of P. talassica × P. euphratica. The growth, physiological characteristics and anatomical characteristics of P. talassica × P. euphratica under NaCl-stress treatments showed that it had good salt tolerance and adaptability, and the 200 mmol/L NaCl-stress treatment promoted the growth of P. talassica × P. euphratica to a certain extent. This study provided a theoretical basis for the study of the salt-tolerant mechanism of P. talassica × P. euphratica.

Hydraulic constraints determine the distribution of heteromorphic leaves along plant vertical height

As an interesting and important trait of some drought-tolerant species, heteromorphic leaves are distributed differentially along plant vertical heights. However, the underpinning mechanism for the formation of heteromorphic leaves remains unclear. We hypothesize that heteromorphic leaves are caused by the hydraulic constraints possibly due to the compensation of the changes in functional traits in response to water transport capacity or the reduction of ineffective water loss. In this study, differences in water transport capacity, morphological traits, anatomical structures, and cellular water relations among three typical types of heteromorphic leaves (i.e., lanceolate, ovate, and broad-ovate) of Populus euphratica Oliv. (a dominant species of desert riparian forest in Central and West Asia) and their relationships were analyzed in order to explore the forming mechanism of heteromorphic leaves. The results showed that the lanceolate, ovate, and broad-ovate leaves were growing in the lower, intermediate, and higher positions from the ground, respectively. Morphological traits, anatomical structures, cellular water relations, and water transport capacity significantly varied among the three types of heteromorphic leaves (P< 0.01). Drought stress in broad-ovate leaves was significantly higher than that in ovate and lanceolate leaves (P< 0.01). Water transport capacity has significant correlations with morphological traits, anatomical structures, and cellular water relations (R ² ≥ 0.30; P< 0.01). Our results indicated that heteromorphic leaves were used as an important adaptive strategy for P. euphratica to alleviate the increase of hydraulic constraints along vertical heights.

Anatomical Structures Responsible for CTEV Relapse after Ponseti Treatment

Relapse of deformity after a successful Ponseti treatment remains a problem for the management of clubfoot. An untreated varus heel position and restricted dorsal flexion of the ankle are the main features of recurrences. We analyze the anatomical structures responsible for these recurrences. Materials and methods: During 5 years, 52 children with CTEV (Congenital Talipes Equino Varus) were treated with casts according to the Ponseti method, with a mean number of 7 casts. Closed percutaneous tenotomy was performed in 28 infants. Children were followed monthly and treated with the continuous use of a molded cast. We had 9 children with relapsed clubfeet. During the standing and walking phase, they had a fixed deformity with a varus position of the heel and dorsal flexion of the ankle <10 d. They were surgically treated with the posterolateral approach. Results: In all patients, we found a severe thickening of the paratenon of the Achilles in the medial side, with adhesions with the subcutaneous tissue. The achilles after the previous tenotomy was completely regenerated. The achilles was medially displaced. Conclusions: A severe thickening of the paratenon of the achilles and adhesions with the subcutaneous tissue are anatomical structures in fixed relapsed cases of clubfoot. We treated our patients with an appropriate surgical release.

[A classification of surgical guides application for dental implantation]

In dental implantology the treatment planning is the most important item for surgery success as well as for functionality and aesthetics of denture. The current problem is to determine the implant position intraoperatively. On dental market there are many companies offering the different variants of navigation surgery, including surgical guides. The purpose of this study is to create universal classification of surgical guide application for dental implantation based on clinical setting and the individual anatomy of the patient which simplifies the medical activities and predictably performs the treatment protocol.

Web Browsing Habits of Healthcare Professions Students in Gross Anatomy Laboratory

Personal computer use for educational purposes by the healthcare professions students has become ubiquitous. Although the effect of computer-based dissection instructions has been studied, there is a paucity of information regarding student browsing habits of information available on the Internet. Although current students have favorable attitudes toward accessing anatomical information online, web browsing habits have not yet been investigated specifically in the dissection laboratory setting. The purpose of this study was to describe the browsing habits of the healthcare professions students in the gross anatomy setting using a retrospective analysis. Files containing web browser history were retrieved from desktop computers in the gross anatomy laboratory and custom code was written to parse them into comma separated value files. Each web address was categorized and descriptive statistics was calculated. Browser history for 24 computers was analyzed from June 2013 to January 2015. During this period, students accumulated 100,857 webpage visits. Most often, students performed a Google search for anatomy (22.0% of all visits) and non-anatomy related (20.6% of all visits) information. Students also used the web browser to access various entertainment (16.4% of all visits) and productivity related services (15.9% of all visits). This analysis revealed a large volume of webpage visits by the healthcare professions students in the gross anatomy laboratory. A wide diversity of anatomy and non-anatomy related webpages were visited. Future analyses could be directed at examination of when in relation to class time students accessed the information, how browsing habits change over time, and what anatomical structures were most commonly searched for.

Mesophyll conductance in cotton bracts: anatomically determined internal CO2 diffusion constraints on photosynthesis

Mesophyll conductance (gm) has been shown to affect photosynthetic capacity and thus the estimates of terrestrial carbon balance. While there have been some attempts to model gm at the leaf and larger scales, the potential contribution of gm to the photosynthesis of non-leaf green organs has not been studied. Here, we investigated the influence of gm on photosynthesis of cotton bracts and how it in turn is influenced by anatomical structures, by comparing leaf palisade and spongy mesophyll with bract tissue. Our results showed that photosynthetic capacity in bracts is much lower than in leaves, and that gm is a limiting factor for bract photosynthesis to a similar extent to stomatal conductance. Bract and the spongy tissue of leaves have lower mesophyll conductance than leaf palisade tissue due to the greater volume fraction of intercellular air spaces, smaller chloroplasts, lower surface area of mesophyll cells and chloroplasts exposed to leaf intercellular air spaces and, perhaps, lower membrane permeability. Comparing bracts with leaf spongy tissue, although bracts have a larger cell wall thickness, they have a similar gm estimated from anatomical characteristics, likely due to the cumulative compensatory effects of subtle differences in each subcellular component, especially chloroplast traits. These results provide the first evidence for anatomical constraints on gm and photosynthesis in non-leaf green organs.

Risk of Damaging Anatomical Structures During Minimally Invasive Hallux Valgus Correction (Bösch Technique): An Anatomical Study

BACKGROUND

Percutaneous, transverse distal metatarsal osteotomy with K-wire fixation (the Bösch technique) is an established technique for hallux valgus correction. Nevertheless, the risk of damaging the anatomical structures during the operation is unknown.

METHODS

Forty fresh-frozen anatomical foot specimens with hallux valgus deformity underwent a percutaneous corrective procedure. Specimens of group A (n = 20) were operated by an experienced surgeon while specimens of group B (n = 20) were done by untrained residents.

RESULTS

The dorsal cutaneous nerve was injured in 1 of 20 cases in group A and 6 of 20 cases in group B ( P = .037). There was a significant difference in overall complication rate between specimens of group A and group B ( P = .043).

CONCLUSIONS

The results show an increased risk of perioperative injury of the dorsal cutaneous branch of the deep peroneal nerve as well as a significant effect of the surgeon's experience on the overall complication rate.

CLINICAL RELEVANCE

Results of this study are highly relevant for all surgeons who perform percutaneous, minimally invasive hallux valgus surgery to avoid damage to the peripheral nerves. In addition, the data suggest an intensive training for surgeons before minimally invasive hallux valgus surgery is performed without supervision.