In search of clinical truths: equine and comparative studies of anatomy

Ultrasonography, computed tomography and magnetic resonance imaging of the dromedary camel distal limbs

BACKGROUND

Lameness associated with the distal limb region in dromedary camels is quiet prevalent. The diagnosis of lameness relies on a comprehensive orthopedic examination conjugated with an appropriate imaging modality to achieve a decisive diagnosis. Using of modern imaging tools provoked a significant breakthrough in the diagnosis of lameness. Ultrasonography (US) is widely established in dromedaries, whereas computed tomography (CT) and magnetic resonance imaging (MRI) are gaining popularity. CT provides a considerably higher bone detail than any other imaging modality. US and MRI continue to be the best options for soft tissue imaging. A truthful assessment of the clinical US, CT and MRI images dictates a comprehensive familiarity with the standard US, CT and MRI tissue deviations. Accordingly, our purposes were to present a full MRI protocol for investigating the dromedary camel distal limbs as well as comparing and illustrating the merits of using MRI, CT and US for evaluation of the front and hind distal limbs in 10 healthy lameness free dromedary camel cadavers. The limbs were scanned via a high-field 1.5 Tesla MRI magnet and a multi-detector CT scanner then subjected to a systematic US examination in both longitudinal and transverse planes. The obtained MRI, CT and US images were evaluated, correlated and compared.

RESULTS

CT and MRI eliminated the structural superimposition in the dromedary camel distal limbs and afforded assessment of minute ligamentous and tendentious structures that were inaccessible by US including the axial collateral ligaments, ligaments supporting the proximal sesamoid bones and the palmar/plantar aspects of the inter-phalangeal joints. US and MRI were appreciated for the assessment of the articular cartilage that was not visible on the plain CT images.

CONCLUSIONS

CT and MRI accurately identified and characterized bones and soft tissues constituting the dromedary camel distal limbs. US was appreciated for assessment of soft tissues, articular cartilage and bone contours. CT and MRI may be considered when US results are inconclusive or to evaluate the unreachable parts of the camel distal limbs. Images presented in this study could be used as a reference standard for evaluating dromedary camel distal limb diseases.

Magnetic resonance imaging, computed tomography, and gross anatomy of forelimb joints in New Zealand rabbit (Oryctolagus cuniculus L.)

The present study aimed to define the anatomical structures by comparing the transversal computed tomography (CT) and magnetic resonance (MR) images of the forelimb joints of the rabbits with the cross-sectional plastinated images. A total of 14 (seven females, seven males) one-year-old adult New Zealand rabbits were used in the study. After the CT and MR imaging procedures were completed, the forelimbs were removed from the body. The forelimbs were plastinated using the silicone plastination method and sectioned transversal. Cross-sectional plastinates were evaluated and correlated anatomically with conjugate CT and MR images. Joint and surrounding anatomical structures were defined in sections. Cross-sectional plastinated samples were highly correlated with CT and MR images in terms of bone and soft tissue, respectively. It is thought that the anatomical and radiological data obtained from the forelimb joints of rabbits will provide a basis for scientists who are involved in both experimental surgical interventions and clinical anatomy education.

Evaluation of a 3D Computer Model of the Equine Paranasal Sinuses as a Tool for Veterinary Anatomy Education

Detailed knowledge of anatomical systems is vital for clinical veterinary practice. However, students often find it difficult to transfer skills learned from textbooks to real-life practice. In this study, a three-dimensional computer model representing equine paranasal sinus anatomy (3D-ESM) was created and evaluated for its contribution to student understanding of the 3D dynamic nature of the system. Veterinary students and equine professionals at the University of Bristol were randomly allocated into experimental (3D model) and control (2D lecture) groups. A pre-/post-study design was used to evaluate the efficacy of the 3D model through a pre-/post-multiple-choice question (MCQ) anatomical knowledge exam and a pre-/post-questionnaire gathering information on participant demographics, confidence, and satisfaction. No statistically significant difference was found between 3D and 2D groups' post-MCQ exam scores (t39 = 1.289, p = .205). 3D group participant feedback was more positive than 2D group feedback, and 3D group satisfaction scores on Likert questions were significantly higher (t118 = -5.196, p < .001). Additionally, confidence scores were significantly higher in the 3D group than in the 2D group immediately following the study (p < .05). Participants' open-text responses indicated they found the 3D model helpful in learning the complex anatomy of the equine paranasal sinuses. Findings suggest the 3D-ESM is an effective educational tool that aids in confidence, enjoyment, and knowledge acquisition. Though it was not better than traditional methods in terms of anatomy knowledge exam scores, the model is a valuable inclusion into the veterinary anatomy curriculum.

Normal anatomic reference of pastern and coffin joints in Egyptian buffalo (Bubalus bubalis): A compared atlas of cross-sectional anatomy, magnetic resonance imaging and computed tomography

The purpose of this study was to describe normal magnetic resonance imaging and computed tomographic anatomy of pastern and coffin joints in Egyptian buffalo using cadaveric distal limbs. This study was achieved using twelve fresh cadaveric distal limbs from adult healthy buffaloes of both sexes. These cadaveric limbs were scanned using a 1 Tesla MRI scanner and CT scanner, injected with red latex, frozen at -20°C for 1 week, and then sectioned into sagittal, dorsal and transverse slices. The obtained MR and CT images were selected to be matched with their corresponding anatomical cross-sections for identification and evaluation of the clinically correlated anatomical structures of the pastern and coffin joints. The difference in signal intensities on CT and MRI scans amongst the tissues allowed clear differentiation of major bone and soft tissue structures of the pastern and coffin joints. CT provided a high spatial resolution of bone and soft tissue structures, however, MRI allowed a better and higher resolution and definition between soft tissues. The current study provided a normal CT and MRI anatomic reference which could help veterinary clinicians for interpretation and diagnosis of the clinically affected pastern and coffin joints in buffalo.

Differentiation of Anatomic Entities in the Dog Stifle Joint Following S10B Plastination: Comparative Colorimetric and Radiological Investigations

The knee joint is not only the most important and complex structure to present during anatomy lectures, but also a significant region for radiologists and orthopedicians. The objectives of this paper are: 1) to evaluate the efficacy of plastinated specimens by measuring colorimetric differentiation and 2) to compare the anatomical structures of the images obtained from computed tomography (CT) and silicone plastination cross-sections and perform three-dimensional (3D) reconstructed models of the specimens. A total of 16 knee joints selected from the 10% formalin fixed/dissected group (n=6), non-fixed/dissected group (n=6) and non-dissected whole knee joint group (n=4) were scanned by CT and plastinated by using the S10B silicone technique. The color changes of the structures were quantitatively determined with the colorimeter device. Plastinated whole knee joints were cut transversally with a band saw and compared with CT images. Finally, 3D reconstruction of the knee joints was performed from CT images with the 3D reconstruction program. There were statistically significant differences between the fixed and non-fixed groups in terms of color changes (p<0.001). The anatomical structures were identified and matched in the cross-sections of plastinates and corresponding CT images. It was observed that plastinated samples were elastic, durable and non-hazardous specimens to use in the veterinary orthopedics and anatomy courses and lectures. It has been found that fixation was useful for the final product morphology. It is thought that the 3D images obtained from this study will support comprehension of the relationships between the bones, muscles, and ligaments.

Anatomy Teaching, a "Model" Answer? Evaluating "Geoff", a Painted Anatomical Horse, as a Tool for Enhancing Topographical Anatomy Learning

Development of new methods for anatomy teaching is increasingly important as we look to modernize and supplement traditional teaching methods. In this study, a life-sized equine model, "Geoff," was painted with surface and deep anatomical structures with the aim of improving students' ability to convert theoretical knowledge into improved topographical anatomy knowledge on the live horse. Third and fourth year veterinary medicine students (n = 45) were randomly allocated into experimental (used "Geoff") and control (used textbook) groups. The efficacy of the model was evaluated through a structured oral exam using a live horse. Questionnaires gathered information on student confidence and enjoyment of the task. There was no significant difference in the performance of experimental and control groups either immediately (44±20% vs. 40±21%; P = 0.504) or 9 weeks after the learning intervention (55±17% vs. 55±20%; P = 0.980). There were however specific questions on which the experimental group performed better than controls, and for which gender effects were apparent. The students using "Geoff" showed a transient gain in confidence following the session (Likert scale 2.7 to 3.6) however the initial increase was no longer present at the second test. There was a significant influence of gender on confidence with greater confidence gains in females in the Experimental group. The students found the model to be extremely useful and both groups found the sessions enjoyable. The model will be of benefit as a complementary learning tool for students.

Plastination in Anatomy Learning: An Experience at Cambridge University

Due to lack of objective data, the benefits of using plastination in combination with wet dissection in teaching gross anatomy are unknown. The aim of this study was to obtain objective evidence from students regarding the effectiveness of combining plastinated specimens (PS) with an established gross anatomy education program at Cambridge University that uses wet cadaver dissection and small-group tutorials. For a complete academic year, a total of 135 PS were used alongside wet cadaver dissections. The PS were also available for small-group tutorials. An anonymous closed questionnaire, using a 5-point numerical-estimation Likert scale, was used to gather information relating to the effectiveness of the PS. The level of student satisfaction with the combined use of wet dissections and PS was high, although higher (p<.05) for second-year students (98.4%) than for first-year students (95.5%). Students felt the specimens allowed them to see details that were often more difficult to identify in their dissections, for instance nerves. Voluntary use of PS was higher (p<.01) for second-year students (96.9%), who had previously experienced anatomy teaching with cadaver dissection alone, than for first-year students (77.7%). Overall, 97.7% of all students thought that the PS helped them understand and learn anatomy. All students surveyed (100%) recommended the use of PS in the future. Students considered the use of PS in the dissection room combined with wet cadaver dissection to be beneficial when learning anatomy, particularly when combined with their use during small-group tutorials.

The sinonasal communication in the horse: examinations using computerized three-dimensional reformatted renderings of computed-tomography datasets

Background

Sinusitis is a common disease in the horse. In human medicine it is described, that obstruction of the sinonasal communication plays a major role in the development of sinusitis. To get spatial sense of the equine specific communication ways between the nasal cavity and the paranasal sinuses, heads of 19 horses, aged 2 to 26 years, were analyzed using three-dimensional (3D) reformatted renderings of CT-datasets. Three-dimensional models were generated following manual and semi-automated segmentation. Before segmentation, the two-dimensional (2D) CT-images were verified against corresponding frozen sections of cadaveric heads.

Results

Three-dimensional analysis of the paranasal sinuses showed the bilateral existence of seven sinus compartments: rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, frontal sinus, sphenopalatine sinus and middle conchal sinus. The maxillary septum divides these seven compartments into two sinus systems: a rostral paranasal sinus system composed of the rostral maxillary sinus and the ventral conchal sinus and a caudal paranasal sinus system which comprises all other sinuses. The generated 3D models revealed a typically configuration of the sinonasal communication ways. The sinonasal communication started within the middle nasal meatus at the nasomaxillary aperture (Apertura nasomaxillaris), which opens in a common sinonasal channel (Canalis sinunasalis communis). This common sinonasal channel ramifies into a rostral sinonasal channel (Canalis sinunasalis rostralis) and a caudo-lateral sinonasal channel (Canalis sinunasalis caudalis). The rostral sinonasal channel ventilated the rostral paranasal sinus system, the caudo-lateral sinonasal channel opened into the caudal paranasal sinus system. The rostral sinonasal channel was connected to the rostral paranasal sinuses in various ways. Whereas, the caudal channel showed less anatomical variations and was in all cases connected to the caudal maxillary sinus. Volumetric measurements of the sinonasal channels showed no statistically significant differences (P <0.05) between the right and left side of the head.

Conclusions

Under physiologic conditions both paranasal sinus systems are connected to the nasal cavity by equine specific sinonasal channels. To resolve sinus disease it is aimed to maintain or even reconstruct the normal anatomy of the sinonasal communication by surgical intervention. Therefore, the presented 3D analyses may provide a useful basis.

Using semi-automated segmentation of computed tomography datasets for three-dimensional visualization and volume measurements of equine paranasal sinuses

The system of the paranasal sinuses morphologically represents one of the most complex parts of the equine body. A clear understanding of spatial relationships is needed for correct diagnosis and treatment. The purpose of this study was to describe the anatomy and volume of equine paranasal sinuses using three-dimensional (3D) reformatted renderings of computed tomography (CT) slices. Heads of 18 cadaver horses, aged 2-25 years, were analyzed by the use of separate semi-automated segmentation of the following bilateral paranasal sinus compartments: rostral maxillary sinus (Sinus maxillaris rostralis), ventral conchal sinus (Sinus conchae ventralis), caudal maxillary sinus (Sinus maxillaris caudalis), dorsal conchal sinus (Sinus conchae dorsalis), frontal sinus (Sinus frontalis), sphenopalatine sinus (Sinus sphenopalatinus), and middle conchal sinus (Sinus conchae mediae). Reconstructed structures were displayed separately, grouped, or altogether as transparent or solid elements to visualize individual paranasal sinus morphology. The paranasal sinuses appeared to be divided into two systems by the maxillary septum (Septum sinuum maxillarium). The first or rostral system included the rostral maxillary and ventral conchal sinus. The second or caudal system included the caudal maxillary, dorsal conchal, frontal, sphenopalatine, and middle conchal sinuses. These two systems overlapped and were interlocked due to the oblique orientation of the maxillary septum. Total volumes of the paranasal sinuses ranged from 911.50 to 1502.00 ml (mean ± SD, 1151.00 ± 186.30 ml). 3D renderings of equine paranasal sinuses by use of semi-automated segmentation of CT-datasets improved understanding of this anatomically challenging region.