First report of kyphoscoliosis in the narrow-ridged finless porpoises (Neophocaena asiaeorientalis): Findings from congenital and degenerative cases comparison using post-mortem computed tomography.

INTRODUCTION: Spinal deformities, including kyphoscoliosis, have been consistently documented in cetaceans. However, the majority of reported cases of kyphoscoliosis in cetaceans pertain to bottlenose dolphins, with limited information on its occurrence in narrow-ridged finless porpoise (NFP) (Neophocaena asiaeorientalis). MATERIALS AND METHODS: In November 2021, two deceased NFPs were discovered stranded on the shores of the Republic of Korea. As part of the pioneer stranded cetacean imaging programme in the Republic of Korea, both carcasses underwent post-mortem computed tomography (PMCT), revealing congenital and degenerative traumatic kyphoscoliosis, respectively. RESULTS: Although kyphoscoliosis may not have directly caused the demise of these individuals, it is hypothesized that the reduced spinal range of motion and mobility associated with kyphoscoliosis may have contributed to their deaths. CONCLUSION: This case report presents the first documented cases of kyphoscoliosis in two NFPs stranded in Korean waters, utilizing PMCT as an efficient methodology for assessing skeletal abnormalities in cetaceans.

Adhesive Bowel Obstruction (ABO) in a Stranded Narrow-Ridged Finless Porpoise (Neophocaena asiaeorientalis sunameri).

In this case report, we present a rare occurrence of a narrow-ridged finless porpoise (Neophocaena asiaeorientalis sunameri), discovered on the coast of Jeju Island, Republic of Korea, that was afflicted with adhesive bowel obstruction (ABO), a life-threatening condition that has scarcely been reported in cetaceans. Diagnosis of ABO was confirmed via radiological and clinical assessments. Post-mortem computed tomography and necropsy revealed ABO between two loops of the jejunum at the L8 level. The mesenteric tissue covering the intestinal lesion was severely thickened with increased tension. Both bowel loops were fixed to the mesentery and acutely angulated, leading to asymmetrical thickening of the cross-sectional bowel walls. The intestinal lumen was stenosed because of pressure from the firm mesenteric band, and no fecal matter was observed in the lumen of the posterior bowel or rectum. Calcified nodules were detected, and histological analysis suggested parasitic or suspected post-parasitic infections. The primary cause of the intestinal lesions is presumed to be a reaction related to parasitic infection. However, further investigations would establish a definitive link between parasitic infections and ABO in this species. This case highlights the importance of studying rare medical conditions in wildlife, providing valuable insights into marine mammal health.

Fatal upper aerodigestive tract obstruction in an East Asian finless porpoise (Neophocaena asiaeorientalis sunameri): findings in post-mortem computed tomography.

The present case report aims to outline the post-mortem findings of an East Asian finless porpoise with upper aerodigestive tract obstruction using different post-mortem computed tomography (PMCT) visualization techniques and discusses the potential cause of death of this individual. A dead-stranded adult male East Asian finless porpoise was recovered from the Northern coast of Jeju Island, Republic of Korea. The carcass was frozen in Jeju National University within 2 h upon first reported. The PMCT examinations were performed at 120 kVp, 200 mAs with a section thickness of 1 mm. The scan field of view (sFOV) was set to 400 mm. Four image rendering techniques, including multi-planar reconstruction, three-dimensional volume rendering, perspective volume rendering, and minimum intensity projection technique, were used to aid the diagnosis of upper aerodigestive tract obstruction in the stranded finless porpoise. Conventional necropsy was performed to provide a complete necropsy report. Using PMCT, a Sebastidae of 24 cm measured length was found to be lodged in the left pharyngeal food channel and esophagus of the finless porpoise. Hard rays of the pectoral fin of the lodged fish have impaled the esophageal mucosa. Fishing gear was found to embed at the dorsal side of the lodged fish. The trachea was compressed ventrally and the arytenoepiglottic tube opening has been narrowed, which may precipitate to the finless porpoise difficult breathing. Pulmonary hyperinflation, pulmonary edema, pneumothorax, pneumopericardium, and pneumorrhachis were observed. This case report represents the first documentation of potential radiological indicators of upper aerodigestive tract obstruction in the East Asian finless porpoise using PMCT. Spatial location of the lodged item could be rendered in situ as the time of death. It has demonstrated that PMCT could provide objective measurements to adjunct the necropsy findings in diagnosis of fatal aerodigestive tract obstruction in stranded cetaceans.

Hybrid split-arc partial-field volumetric modulated arc therapy: an improved beam arrangement for linear accelerator-based hippocampal-avoidance whole brain radiation therapy.

Background: This technical note aims to verify the hippocampus and adjacent organs at risk (OARs) sparing ability of an improved beam arrangement, namely hybrid split-arc partial-field volumetric modulated arc therapy (VMAT) (Hsapf-VMAT) during whole brain radiation therapy (WBRT). Materials and methods: Computed tomography simulation images of 22 patients with brain metastases were retrieved in this retrospective planning study. The hippocampus was manually delineated according to the criterion of RTOG 0933. Plans delivering 30 Gy in 10 fractions were generated for each patient using split-arc partial-field VMAT (sapf-VMAT) and Hsapf-VMAT. The sapf-VMAT plans consisted of 4 arc fields of 179.9° each with reduced field size. The Hsapf-VMAT consisted of 4 arc fields similar to sapf-VMAT in addition to 2 lateral opposing static fields. Statistical comparisons between treatment plans of both techniques were performed using the paired t-test at 5% level significance. Results: The results demonstrated that Hsapf-VMAT can achieve superior dose sparing in hippocampus which is comparable to sapf-VMAT (p > 0.05). In both eyes, Hsapf-VMAT had significantly lower Dmean and Dmax compared to sapf-VMAT (p < 0.005). Decrease in Dmax of both lenses using Hsapf-VMAT (p < 0.005) were statistically significant when compared to sapf-VMAT. Hsapf-VMAT demonstrated significant reduction of Dmean and Dmedian to the optic nerves (p < 0.05). Whole brain planning target volume (PTV) coverage was not compromised in both techniques. Conclusion: The present study adopts a hybrid technique, namely Hsapf-VMAT, for hippocampal sparing WBRT. Hsapf-VMAT can achieve promising dose reduction to the hippocampus, both eyes and lenses. Therefore, Hsapf-VMAT can be considered an improved version of sapf-VMAT.

Implementation of web-based open-source radiotherapy delineation software (WORDS) in organs at risk contouring training for newly qualified radiotherapists: quantitative comparison with conventional one-to-one coaching approach.

BACKGROUND: Due to the role expansion of radiotherapists in dosimetric aspect, radiotherapists have taken up organs at risk (OARs) contouring work in many clinical settings. However, training of newly qualified radiotherapists in OARs contouring can be time consuming, it may also cause extra burden to experienced radiotherapists. As web-based open-source radiotherapy delineation software (WORDS) has become more readily available, it has provided a free and interactive alternative to conventional one-to-one coaching approach during OARs contouring training. The present study aims to evaluate the effectiveness of WORDS in training OARs contouring skills of newly qualified radiotherapists, compared to those trained by conventional one-to-one coaching approach. METHODS: Nine newly qualified radiotherapists (licensed in 2017 - 2018) were enrolled to the conventional one-to-one coaching group (control group), while 11 newly qualified radiotherapists (licensed in 2019 - 2021) were assigned to WORDS training group (measured group). Ten OARs were selected to be contoured in this 3-phases quantitative study. Participants were required to undergo phase 1 OARs contouring in the beginning of the training session. Afterwards, conventional one-to-one training or WORDS training session was provided to participants according to their assigned group. Then the participants did phase 2 and 3 OARs contouring which were separated 1 week apart. Phase 1 - 3 OARs contouring aimed to demonstrate participants' pre-training OARs contouring ability, post-training OARs contouring ability and knowledge retention after one-week interval respectively using either training approach. To prevent bias, the computed tomography dataset for OARs contouring in each phase were different. Variations in the contouring scores for the selected OARs were evaluated between 3 phases using Kruskal-Wallis tests with Dunn tests for pairwise comparisons. Variations in the contouring scores between control and measured group in phase 1 - 3 contouring were analyzed using Wilcoxon signed-rank test. A p-value < 0.05 was considered to be statistically significant. RESULTS: In both control group and measured group, significant improvement (p < 0.05) in phase 2 and 3 contouring scores have been observed comparing to phase 1 contouring scores. In comparison of contouring scores between control group and measured group, no significant differences (p > 0.05) were observed in all OARs between both groups. CONCLUSIONS: The results in this study have demonstrated that the outcome of OARs contouring training using WORDS is comparable to the conventional training approach. In addition, WORDS can offer flexibility to newly qualified radiotherapists to practice OARs contouring at will, as well as reduce staff training burden of experienced radiotherapists.

Cross-sectional anatomy, computed tomography, and magnetic resonance imaging of the banded houndshark (Triakis scyllium).

Due to their important phylogenetic position among extant vertebrates, sharks are an invaluable group in evolutionary developmental biology studies. A thorough understanding of shark anatomy is essential to facilitate these studies and documentation of this iconic taxon. With the increasing availability of cross-sectional imaging techniques, the complicated anatomy of both cartilaginous and soft tissues can be analyzed non-invasively, quickly, and accurately. The aim of this study is to provide a detailed anatomical description of the normal banded houndshark (Triakis scyllium) using computed tomography (CT) and magnetic resonance imaging (MRI) along with cryosection images. Three banded houndsharks were scanned using a 64-detector row spiral CT scanner and a 3 T MRI scanner. All images were digitally stored and assessed using open-source Digital Imaging and Communications in Medicine viewer software in the transverse, sagittal, and dorsal dimensions. The banded houndshark cadavers were then cryosectioned at approximately 1-cm intervals. Corresponding transverse cryosection images were chosen to identify the best anatomical correlations for transverse CT and MRI images. The resulting images provided excellent detail of the major anatomical structures of the banded houndshark. The illustrations in the present study could be considered as a useful reference for interpretation of normal and pathological imaging studies of sharks.

Volumetric modulated arc therapy (VMAT) for hippocampal-avoidance whole brain radiation therapy: planning comparison with Dual-arc and Split-arc partial-field techniques.

BACKGROUND: Although whole brain radiation therapy (WBRT) provides palliation and prophylaxis, reduces local recurrence probability and improves overall survival, it is evident that WBRT is associated with neurocognitive deficits due to radiation induced damage of the hippocampus. Therefore, minimizing hippocampal dose to the least possible level is of high clinical relevance. In dual-arc conventional volumetric modulated arc therapy (dac-VMAT), the large irradiation field for whole brain planned target volume (PTV) requires a wide jaw opening in which substantial low dose volume to the hippocampus may be produced due to suboptimal multi-leaf collimator (MLC) movements. The present study investigates the potential of a radiation therapy technique with split-arc and reduced field size, namely split-arc partial-field volumetric modulated arc therapy (sapf-VMAT) to spare the hippocampus during WBRT. METHODS: Computed tomography and magnetic resonance images of 20 patients with brain metastases were retrieved in this retrospective planning study. The hippocampus was manually delineated by single radiation oncologist strictly following the RTOG 0933 atlas definition. Plans delivering 30 Gy in 10 fractions were generated for each patient using dac-VMAT and sapf-VMAT. Dosimetric parameters from both techniques were compared by paired t-test. RESULTS: The results demonstrated that radiation dose to the hippocampus was significantly reduced using sapf-VMAT relative to dac-VMAT plans. sapf-VMAT (7.86Gy, p = 0.001) had significantly lowered average D100% compared to dac-VMAT (9.23 Gy). Decrease in hippocampus Dmax using sapf-VMAT (13.23 Gy, p = 0.001) was statistically significant when compared to dac-VMAT (16.33 Gy). The resulting mean dose to the hippocampus was 9.16 Gy for the for sapf-VMAT. Mean dose of sapf-VMAT was significantly lower than dac-VMAT (10.85 Gy, p < 0.05). In both eyes, sapf-VMAT demonstrated significantly lower Dmean compared to dac-VMAT (p < 0.05). Whole brain PTV coverage was not compromised in both techniques. CONCLUSION: sapf-VMAT has demonstrated significant dose reduction to the hippocampus and both eyes compared to dac-VMAT.

Accuracy and reliability of cetacean cranial measurements using computed tomography three dimensional volume rendered images.

Computed tomography (CT) has become more readily available for post-mortem examination, offering an alternative to cetacean cranial measurements obtained manually. Measurement error may result in possible variation in cranial morphometric analysis. This study aimed to evaluate the accuracy and reliability of cetacean cranial measurements obtained by CT three-dimensional volume rendered images (3DVRI). CT scans of 9 stranded cetaceans were performed. The acquired images were reconstructed using bone reconstruction algorithms. The reconstructed crania obtained by 3DVRI were visualized after excluding other body structures. Accuracy of cranial measurements obtained by CT 3DVRI was evaluated by comparing with that obtained by manual approach as standard of reference. Reproducibility and repeatability of cranial measurements obtained by CT 3DVRI were evaluated using intraclass correlation coefficient (ICC). The results demonstrated that cranial measurements obtained by CT 3DVRI yielded high accuracy (88.05%- 99.64%). High reproducibility (ICC ranged from 0.897 to 1.000) and repeatability (ICC ranged from 0.919 to 1.000 for operator 1 and ICC range from 0.768 to 1.000 for operator 2) were observed in cranial measurements obtained by CT 3DVRI. Therefore, cranial measurements obtained by CT 3DVRI could be considered as virtual alternative to conventional manual approach. This may help the development of a normative reference for current cranial maturity and discriminant analysis studies in cetaceans.