The construction of canine distal limb models used in teaching sonography identification of vegetal foreign bodies.

Musculoskeletal ultrasonography is a useful tool to identify radiolucent vegetal foreign bodies (VFBs). However, limited ultrasound experience and unfamiliarity with the normal sonographic appearance of anatomical structures can decrease clinician confidence. This study aimed to design a reusable silicone model that can teach VFB identification within the canine distal limb. Four canine hindlimbs were used to design the silicone models, and 12 canine distal forelimbs were constructed. The model was constructed using cadaver bones, barley grass (Avena fatua) seeds, and silicone to mimic the anatomy of the canine distal limb with a grass seed VFB. Limbs were randomly grouped based on grass seed locations: (1) the interdigital webbing, (2) the palmar surface of the canine forelimb immediately proximal to the metacarpal pad, (3) the dorsal surface of the distal limb immediately proximal to the proximal phalange, or (4) no grass seed (control) placed. Each limb was systematically ultrasounded and compared with cadaver limbs and clinical VFB cases. A comparison of ultrasonographic images validated the construction, revealing that the simulation model replicates the anatomical and echotexture characteristics of the normal canine distal limb. Furthermore, these models also have a likeness to clinical canine distal limb VFB cases and can be utilized as a training tool.

The use of subchondral bone topography to approximate the center of rotation of the elbow joint in dogs.

OBJECTIVES: The aim of this study was to compare the approximate center of rotation in normal and diseased elbows in dogs. STUDY DESIGN: Cross-sectional study SAMPLE POPULATION: Computer tomography scans of nine dogs with unilateral fragmented medial coronoid process (FMCP). METHODS: A board certified radiologist confirmed that each dog had unilateral FMCP, and a normal contralateral elbow. Digital 3D models of all elbow joints were uploaded into a surgical planning software package. Four axes approximating the center of rotation (COR) of elbow joints were generated using five geometric shapes based on subchondral topography of the humeral condyle radius and ulna. Images showing the locations where axes exited the medial and lateral cortex of the humeral condyle were captured and imported into a second software package, for measurement of distances between exit points and the origin of a system of axes. RESULTS: In normal joints 20/27 (74%) axes exited the medial cortex, and 25/27 (93%) axes exited the lateral cortex cranial and distal to the medial and lateral epicondyles, respectively. In diseased joints 22/27 (81%) axes exited medial cortex and 19/27 (70%) axes exited the lateral cortex, caudal and distal to the medial and lateral epicondyles, respectively. CONCLUSION: Based on CT- derived geometry, the COR of elbow affected with FMCP was generally more caudal than normal. CLINICAL SIGNIFICANCE: External landmarks approximating the location of the elbow COR are provided, and while not validated, may assist in planning, creation, and assessment of procedures for FMCP.

Computed tomographic evaluation of the distal limb in the standing sedated horse: Technique, imaging diagnoses, feasibility, and artifacts.

In several veterinary institutions, adjustments of CT machines have been made that allow for imaging of the standing horse. The risk of general anesthesia is eliminated and the shorter scan completion time reduces cost to clients. The objective of this retrospective, analytical study was to evaluate the technique, imaging diagnoses, feasibility, and image artifacts of multi-slice helical CT of horses' distal limbs acquired under standing sedation. The CT images of 250 horses of various breeds, aged 3-23 years, that underwent standing distal limb CT were evaluated. Three observers assessed the CT images for artifacts and inter-observer agreement was calculated. Eighty-six percent (95% confidence interval (CI), 81-90) of the scans were carried out on the forelimbs, while 14% (95% CI, 10-19) were of the hindlimbs. A total of 65% (95% CI, 59-71) of horses that underwent standing sedated CT had single imaging diagnoses. Seventy-one percent (95% CI, 65-77) of the cases had unilateral lesions, 27% (95% CI, 22-33) had bilateral lesions and 2% (95% CI, 1-4) had no diagnosed lesions. The average CT acquisition time was 17.5 minutes (range = 15-20). The average number of acquisitions per horse was 1.7 (median = 1; range = 1-4). There was good to excellent agreement between all three observers for the presence of motion artifact in the metacarpo/metatarsophalangeal joints, identification of marked beam hardening artifact, mild solar/ skin dirt, and photon starvation artifact (kappa 0.61-0.80). No complications were encountered. Standing examination of the distal limb achieved diagnostic image quality that was obtained with minimal acquisition attempts and in a timely manner.

Radiographic and computed tomographic evaluation of supinator sesamoid bones in dogs.

BACKGROUND: The present study evaluated the frequency of supinator sesamoid bones (SSB) on radiography and computed tomography (CT). Interobserver agreement was evaluated in the detection of the SSBs in both methods. A correlation between the existence of SSBs and elbow diseases (ED) was assessed. For these purposes, radiographs, and CT scans of 100 dogs were scored by 3 observers. RESULTS: The SSB was identified as a round to oval-shaped opacity and measured 0.5-6.56 mm × 0.5-6.2 mm. SSBs were reported in an average of 8,33% of dogs on radiographs and 26% of dogs on CT; a bilateral sesamoid bone was present in 43,52% and 76,92% of these dogs, respectively. Seventy-two percent of the SSBs was identified on CT were not detected on radiographs. The Kappa test showed a substantial agreement (κ = 0.691) and a perfect agreement (κ = 1) between the observers in the detection of SSBs on radiography and on CT scans respectively. Additionally, a weak positive correlation was detected between ED and the existence of SSBs. CONCLUSION: A supinator sesamoid bone can be detected occasionally in the evaluation of the canine elbow joints by routine radiography. CT is superior to radiography for assessing SSBs with a higher interobserver agreement. The correlation of the existence of the SSBs and ED, needs further evaluations to prove a probable pathophysiological connection.

Osteology applied to image diagnosis of the forelimb of the black-striped capuchin (Sapajus libidinosus Spix, 1823).

Macroscopic bone analysis and evaluation through imaging methods are essential in the recognition of natural and altered structures. Therefore, this study aimed at describing the osteology the thoracic limb of Sapajus libidinosus in bone pieces, identifying them in radiographic and tomographic images. For this, four cadavers were used in the macroscopic analysis and five animals for the imaging exams, of which four were euthanized and added to the macroscopic stage. For imaging exams, the animals were kept anesthetized. All bones were documented, structures described, and compared with literature data from human and nonhuman primates. There was no statistical difference between males and females regarding the length of the forelimb bones. Most of the bone structures of the scapula were well identified in the imaging methods, being more restricted in the ventrodorsal projection. The clavicle presented very limited visualization. The humerus, as well as the radius and ulna, were not well portrayed in their proximal and distal epiphyses by radiography. However, they were well identified on tomography. All structures described in the macroscopic image of the carpal and metacarpal bones could be identified through radiography and tomography, and the radiographic examination of this region is an excellent method for identifying fractures. The glenoid notch of the scapula was not visualized by any imaging method. S. libidinosus presented anatomical characteristics more similar to those of neotropical primates and man, being a great indicator of an experimental model for studies in these species.

Applicability of ARFI elastography in detecting elasticity changes of the equine superficial digital flexor tendon with induced injury.

The objectives of this prospective, experimental study were to describe changes in the stiffness of the equine superficial digital flexor tendon (SDFT) after induced injury, deep digital flexor tendon (DDFT), accessory ligament (AL-DDFT), and suspensory ligament (SL) during 90 days of healing using acoustic radiation force impulse (ARFI) elastography. Eight healthy horses were selected. Preinjury B mode and ARFI evaluations were performed bilaterally in the palmar metacarpal region. Injury was induced only on the left forelimb (G2) by a single injection of collagenase in SDFT, 15 cm distal to the accessory carpal bone. The right forelimb was used as a control (G1). Evaluations were performed at eight timepoints: one before injury (T0) and seven (T1-T7) after injury (3, 15, 30, 40, 60, 75, and 90 days post-induction). Tendinopathies were visualized as hypoechoic areas with loss of parallel tendon fiber pattern. Injured SDFTs presented mainly cool colors (soft) from T1 to T3, and from T4, there was an increase in warm colors (hard), close to the appearance of tendons of G1. In the first four timepoints, there was a decrease in stiffness compared to G1 (P < 0.001). On T1 and T2, a cutoff value <6.21 m/s to determine tendinopathy of the SDFT was established (75.8% sensitivity and 92.03% specificity). Stiffness changes in the DDFT, AL-DDFT, and SL of injured limbs occurred at different timepoints. Tendinopathy significantly altered the stiffness of the injured tendon and the adjacent tissues. ARFI made it possible to detect these changes, helping to monitor the reparation of this injury.

Anatomic, computed tomographic, and ultrasonographic assessment of the lymph nodes in presumed healthy adult cats: The head, neck, thorax, and forelimb.

Assessment of the lymph nodes is key in staging cancer patients. Descriptions of normal features of the feline lymph nodes using computed tomography (CT) and ultrasound (US) are limited. A prospective anatomic and comparative imaging study was performed. The frequency of identification and the size of the lymph nodes during gross pathology from 6 feline cadavers were compared to the images of lymph nodes from 30 presumed healthy adult cats obtained by CT and US. Measurements (length, width, and height) were compared among techniques. The CT and US features of the identified lymph nodes were also recorded. The frequency of identification of the lymph centers varied among techniques and individually. The mandibular lymph nodes were identified in 100% of the cadavers and in 100% of the healthy cats using CT and US. The medial retropharyngeal lymph nodes were identified in 100% of the cats using CT and US. The deep cervical lymph nodes were not visualized in the cadavers. The cranial mediastinal and tracheobronchial lymph nodes were not visualized using US. Lymph nodes showed a higher length on CT and higher width on US. The height was the most statistically significant variable measurement among techniques. On CT, lymph nodes were most frequently isoattenuating or slightly hypoattenuating to surrounding musculature, with homogeneous contrast enhancement. On US, most lymph nodes were isoechoic or hypoechoic to surrounding fat tissue. The lymph nodes were most frequently elongated or rounded.

Computed tomography findings in a cohort of 169 dogs with elbow dysplasia - a retrospective study.

BACKGROUND: Canine elbow dysplasia (CED) is a complex developmental skeletal disorder associated with a number of pathological conditions within the cubital joint. Because CED is a heritable disease, it is important to identify and remove the affected animals from breeding. The first objective of this study was to describe the prevalence of medial coronoid process disease (MCPD) without (MCD) or with (FMCP) fragmented medial coronoid process, osteochondrosis (OC) and/or osteochondritis dissecans (OCD), ununited anconeal process (UAP), radio-ulnar incongruence (INC R-U) and humero-ulnar incongruence (INC H-U) in dogs with the use of CT imaging. The second aim was to determine the influence of demographics on the prevalence of investigated pathologies in dogs with clinical evidence of elbow dysplasia. RESULTS: In this retrospective study, CT data records of 169 dogs of different breeds presented to the small animal veterinary clinic from 2012 to 2018 were included. 69.23% of dogs diagnosed with CED were young (≤ 2 years old). The mean age of dogs presented with INC R-U was 1.68 ± 1.82 years, while in dogs without INC R-U the mean age was 2.64 ± 2.59 years. The mean age of dogs with INC H-U was 1.94 ± 2.06 years, while without INC H-U 3.29 ± 2.09 years. Labrador Retrievers, German Shepherd and Bernese Mountain dogs were most frequently presented with CED-associated lameness. In 122 dogs OA of varying severity was found. CONCLUSION: INC H-U, FMCP and MCD were among the most frequently found components of CED found in the present study. OCD and UAP were the least frequently diagnosed. Dogs presented with INC R-U and INC H-U were significantly younger than dogs without these CED components. Boxers, Dog de Bordeaux, American Staffordshire terriers and mixed-breed dogs were diagnosed later in life than the other breeds. OA of varying severity was found in 72.18% of dogs. Males accounted for more than 75% of the study population.

Factors affecting successful ultrasound-guided injection into the podotrochlear bursa using a palmarolateral approach.

OBJECTIVE: To evaluate potential factors affecting ultrasonographic visibility of the suprasesamoidean region and the success rate of ultrasound-guided injection (USGI) into the podotrochlear bursa (PB). STUDY DESIGN: Ex vivo, experimental study. ANIMALS: 24 cadaveric forelimbs. METHODS: The PB was distended with 0, 1, or 2 ml of iodinated contrast material and saline under radiographic guidance. Ultrasonographic visibility of the suprasesamoidean region and PB was graded before and after distention with the limb loaded in three positions (vertical, cranial and caudal). Two operators with different experience levels performed an USGI into the PB with methylene blue (12 limbs each [four limbs with each of three volumes of PB distension]) using a palmarolateral approach and caudal foot placement. Limbs were frozen and sectioned to assess accuracy. RESULTS: Ultrasonographic visibility scores of the suprasesamoidean region (p = .0081) and PB (p < .0001) were improved using a caudal foot placement. Higher visibility grades of the suprasesamoidean region were associated with higher injection success rate (p = .047). The injection success was 75% (9/12) for the experienced versus 41.6% (5/12) for the less experienced operator (p = .14). PB distension improved visibility during caudal foot placement (p = .013) but not injection success rates (p = .78). CONCLUSION: Caudal foot placement enhances visibility of the PB and suprasesamoidean region. Limbs with poor visibility of the suprasesamoidean region are more likely to undergo a failed USGI. CLINICAL SIGNIFICANCE: The lateral USGI approach should be performed only in cases of optimal visibility. The reported success rates support the technical challenge of PB injections.

Feasibility, indications, and radiographically confirmed diagnoses of standing extremity cone beam computed tomography in the horse.

OBJECTIVE: To report on the feasibility, indications, and diagnostic yield of cone beam computed tomography (CBCT) of horses' extremities performed under standing sedation. STUDY DESIGN: Retrospective clinical case series. SAMPLE POPULATION: Fifty-nine CBCT examinations in 58 horses. METHODS: Examinations were categorized for indications for CBCT dependent on a suspicion, presence, or absence of a diagnosis prior to CBCT. The number of acquisitions per examination, total time for the examination, diagnostic score of each acquisition (diagnostic, diagnostic-compromised, nondiagnostic), and additional diagnostic information regarding preexisting diagnostic information were recorded. RESULTS: Three (median) acquisitions were performed per examination in a median study time of 14 minutes. In 24 of 33 cases with a suspected diagnosis, this diagnosis was confirmed or definitively refuted; in seven of 33 cases, the suspected diagnosis was refuted without a new diagnosis; and, in two of 33 cases, the suspected diagnosis could not be confirmed nor could a new diagnosis be made. In five of nine cases without a preexisting diagnosis, a diagnosis was established. In 16 cases with a diagnosis prior to CBCT, additional information was recorded, or a surgical plan was prepared. In 14 of 18 cases in which additional contrast techniques were used, additional information was gained. CONCLUSION: Standing CBCT of the horses' extremities is feasible and can produce diagnostic information in a timely fashion. CLINICAL SIGNIFICANCE: The results provide evidence of the practicality and diagnostic potential of standing CBCT of horses' extremities.

Comparison of needle arthroscopy, traditional arthroscopy, and computed tomography for the evaluation of medial coronoid disease in the canine elbow.

OBJECTIVE: To evaluate the diagnostic value of still images of needle arthroscopy (SNAR), still images of traditional arthroscopy (STAR), and computed tomography (CT) to diagnose medial coronoid process (MCP) pathology. STUDY DESIGN: Prospective clinical trial. ANIMALS: Dogs (n = 17) presented for evaluation of elbow dysplasia. METHODS: For each case, two SNAR and STAR images of the MCP were reviewed independently and in random order by three board-certified surgeons. Computed tomographic images were reviewed by one board-certified radiologist. Reviewers were blinded to surgical and clinical findings. Surgical findings from real-time TAR with palpation were used as the gold standard. Receiver operating characteristic (ROC) curves and concordance statistics tests for the diagnostic accuracy of MCP fissure, MCP fragment, medial compartment condition, and cartilage score were calculated. RESULTS: Images of 27 elbows joints were reviewed. For MCP fissure detection, areas under the ROC curves for CT (0.84), STAR (0.73), and SNAR (0.57) did not differ. For the detection of MCP fragment, STAR had a larger area under the ROC curve (0.93) compared with SNAR (0.74, P = .015) and CT (0.54, P < .001). Still images of TAR and SNAR had comparable concordance for cartilage score (0.80 and 0.77, respectively) and medial compartment pathology (0.80 and 0.73, respectively). CONCLUSION: Still images of NAR, STAR, and CT had similar diagnostic value to identify MCP fissures. Still images of TAR was superior to SNAR and CT to identify MCP fragments. CLINICAL SIGNIFICANCE: The diagnostic accuracy of SNAR varied on the basis of the coronoid lesion being evaluated.

Comparison of 18F-sodium fluoride positron emission tomography and CT: An exploratory study in 12 dogs with elbow pain.

18F-Sodium Fluoride (18F-NaF) positron emission tomography (PET) provides high resolution functional information about bone activity and can be fused with CT images to improve three-dimensional localization and characterization of lesions. This prospective, observational study assessed 18F-NaF PET-CT for imaging of canine elbows, compared PET with CT findings, and assessed correlation with lameness. Twelve patients with elbow pain were included. Cases included primarily young, large breed dogs. A three-level clinical lameness score was assigned to each forelimb. All dogs had bilateral elbow joints imaged with CT and PET under general anesthesia, approximately 1.5 h after intravenous injection of 3 MBq/kg of 18F-NaF. Imaging findings were independently reviewed by two radiologists using a three-level scoring scheme over nine anatomical regions in the elbow. PET imaging identified areas of bone activity where minimal change was identified on CT. PET imaging also demonstrated absence of uptake in areas where modeling was present on CT. A stronger correlation was observed between clinical grades and PET scores (r2  = 0.38, P = .001) than between clinical grades and CT scores (r2  = 0.17, P = .048). The total PET scores were significantly different for each clinical grade (P = .013) but total CT scores did not differ (P = .139). This exploratory study suggests that PET improves the ability to detect lesions and to determine the clinical significance of CT findings in dogs with elbow pain.

MRI of osteosarcoma metastases in the brain of an old English Sheepdog.

A 9-year-old, male neutered old English Sheepdog was presented for further investigation of altered mentation, impaired vision, and hemineglect syndrome of 10 days duration. An MRI study of the brain revealed multifocal, contrast-enhancing intra-axial lesions that had a stippled hypointense appearance in all sequences but lacked evidence of a strong signal void on T2* images. Histological examination of the brain postmortem confirmed the lesions were metastases arising from an osteosarcoma, which was later identified in the right humerus. To the authors' knowledge, these MRI characteristics of osteosarcoma metastases in the canine brain have not been previously reported.

Radiographic evaluation of the forelimbs and hind limbs of marmosets (Callithrix spp.).

BACKGROUND: The maintenance of marmosets in captivity may trigger various disorders. The objective of this study was to provide a radiographic evaluation of the forelimbs and hind limbs of marmosets rescued from illegal wildlife trade and maintained in captivity. METHODS: Fourteen marmosets were studied. RESULTS AND CONCLUSIONS: Three marmosets were apparently normal. Of the eleven marmosets with radiographic changes in the hind limbs, five had pelvic narrowing and bilateral varus deviation of the femur, with one suggestive of rickets and another of osteomalacia. The other marmosets showed changes such as malunion of acetabular fracture, transtibial amputation, tibial antecurvatum, and knee osteoarthritis. Six marmosets showed alterations in the forelimbs such as radius fracture, scapulohumeral subluxation, and elbow joint incongruence. In conclusion, 78.57% of the marmosets had bone and/or joint changes detected by plain radiography, which were found predominantly in the hind limbs and without impediment to locomotion in captivity.

Comparison of lameness outcomes in horses with acute or chronic digital lameness that underwent magnetic resonance imaging.

Aims: To compare the outcome, in terms of lameness score or return to athletic function, of horses with acute vs. chronic digital lameness that underwent magnetic resonance imaging (MRI) of the distal limb and to compare the proportion of horses that received intra-articular therapy of the distal interphalangeal (DIP) joint and pattern of diagnostic analgesia in these groups. Methods: This is a retrospective study of horses (n = 95) with acute (≤12 weeks; n = 46) or chronic (>12 weeks; n = 49) digital lameness that underwent MRI of the distal limb from 2009-2016, at two equine referral centres in the USA. Criteria for inclusion in the study were that a majority of lameness localised distal to the fetlock, and that lameness assessments for ≥12 months following MRI could be obtained from the medical record or the owner could be interviewed regarding their horse's athletic function. Outcome was characterised by an improvement score where 2 = return to work at a previous or higher level or lameness improved by one grade or more, 1 = return to work at a lower level or lameness improved by less than one grade, and 0 = did not return to work or lameness grade worsened. Whether horses had received intra-articular therapy of the DIP joint and the pattern of diagnostic analgesia prior to MRI was also obtained from medical records or by interviewing the owner. Results: There was a difference (p = 0.004) in the proportion of horses assigned to improvement scores of 0, 1 and 2 between horses with acute or chronic lameness. There was no evidence of a difference in the likelihood of having received intra-articular therapy of the DIP joint prior to MRI between horses with chronic or acute lameness (p = 0.085). Similarly, there was no evidence of a difference in the pattern of diagnostic analgesia prior to MRI between the two groups (p = 0.94). Eighty-two percent of owners of horses with acute and 62% of those with horses with chronic lameness had a positive opinion of the utility of MRI as a diagnostic modality. Conclusion: In a population of horses with digital lameness undergoing MRI, a difference in the outcome, in terms of lameness score or return to athletic function was identified between horses with acute lameness compared to those with chronic lameness. Clinical relevance: Horses with digital lameness that undergo MRI when the lameness is acute may have an improved prognosis due to accurate diagnosis and earlier application of appropriate therapy.

The intra- and intertester repeatability of radiographic elbow incongruity grading is high in chondrodystrophic dog breeds.

Elbow incongruity is a form of elbow dysplasia that causes osteoarthritis, pain, and lameness, and it is common in chondrodystrophic dog breeds. The objective of this retrospective secondary analysis study was to evaluate the intra- and interobserver repeatability of a novel radiographic incongruity grading system for assessing elbow incongruity in three chondrodystrophic dog breeds-the dachshund, Skye Terrier, and Glen of Imaal Terrier. We conducted an observer agreement study that included 220 mediolateral antebrachial radiographs from 110 dogs with the elbow in 90° flexion. The radiographs were independently assessed by three observers at three time points, using a four-stepped grading scale. The proportion of agreement and Kappa coefficient were calculated. Both the intra- and interobserver proportions of agreement were substantial when three grades were required to be identical (.705-.777 and .609, respectively), and almost perfect for two identical grades (.991-1.000 and .991, respectively). Some differences in repeatability between breeds were noted; specifically, the intraobserver repeatability was higher in the dachshund, and the interobserver repeatability was lower in the Glen of Imaal Terrier. Our study showed that the radiographic imaging protocol and incongruity grading system have high repeatability when assessing elbow incongruity in chondrodystrophic dog breeds.

Risk of intra-articular injection with longitudinal ultrasound-guided injection of collateral ligaments of the equine distal interphalangeal joint.

Desmopathy of the collateral ligaments of the distal interphalangeal joint is a common cause of equine foot lameness and carries a poor prognosis with conservative management. Intralesional injections may improve healing, although accuracy of radiographically guided injections is significantly less than when guided by MRI, which requires special needles. Longitudinal ultrasound-guided injection of the distal collateral ligament has not been evaluated objectively. In this prospective, anatomic study, seven equine cadaver limbs (14 collateral ligaments) were injected with methylene blue dye and radiographic contrast medium using ultrasound to guide the needle longitudinally into the collateral ligaments until contacting bone. The insertion site of the needle proximal to the coronary band was measured on the limb and the needles left in place for radiography and CT to evaluate the needle angulation, location of the contrast medium, and whether the contrast entered the distal interphalangeal joint. The limbs were frozen and sectioned with a band saw to identify the location of the dye. Fifty percentage of injections were in or around the collateral ligaments. However, the percentage of "successful" injections, defined as in the collateral ligament but not in the joint, was only 36%. All legs had dye and contrast in the joint after both ligaments had been injected. There were no significant differences between the needle angle and entry site for "successful" and "unsuccessful" injections. Findings from this study indicates that the success rate is low for injecting the distal portions of the distal interphalangeal joint collateral ligaments using ultrasound guidance alone.

Standing MRI lesions of the distal interphalangeal joint and podotrochlear apparatus occur with a high frequency in warmblood horses.

Foot pain is a common presenting complaint in Warmblood horses. The aim of this retrospective, cross-sectional study was to determine the spectrum of foot lesions detected by magnetic resonance imaging (MRI) in Warmblood horses used for dressage, jumping, and eventing. The medical records of 550 Warmblood horses with foot pain that were scanned using standing MRI were reviewed and the following data were recorded: signalment, occupation, lameness, diagnostic analgesia, imaging results, treatments, and follow-up assessments. Associations between standing MRI lesions and chronic lameness following treatment were tested. Abnormalities of the navicular bone (409 horses, 74%), distal interphalangeal joint (362 horses, 65%), and deep digital flexor (DDF) tendon (260 horses, 47%) occurred with the highest frequency. The following abnormalities were significantly associated (P < .05) with chronic lameness following conservative therapy: moderate to severe MRI lesions in the trabecular bone of the navicular bone, mild or severe erosions of the flexor surface of the navicular bone, moderate sagittal/parasagittal DDF tendinopathies, and moderate collateral sesamoidean desmopathies. Also, identification of concurrent lesions of the DDF tendon, navicular bone, navicular bursa, and distal sesamoidean impar ligament was associated with chronic lameness after conservative therapy. Development of effective treatment options for foot lesions that respond poorly to conservative therapy is necessary.

RADIOGRAPHIC ANATOMY OF THE FORELIMB IN THE NORTHERN TAMANDUA (TAMANDUA MEXICANA).

The thoracic limb anatomy of anteaters in the family Myrmecophagidae is specialized for accessing termite and ant nests and for defense purposes. In the case of the northern tamandua (Tamandua mexicana), the forelimbs are also adapted for arboreal and terrestrial locomotion. Unfortunately, this species faces many conservation threats, such as habitat loss and traffic accidents, and injured individuals are frequently taken to wildlife rehabilitation centers. However, lack of knowledge of the radiographic osteoanatomy of this species may prevent appropriate management of injuries and thereby reduce the chances of successful release and survival. In order to fill this knowledge gap, this article describes for the first time the radiographic anatomy of the thoracic limb of the northern tamandua using four standard views and one additional view. The additional orthogonal view helps visualize structures, such as the hamatus process and the sesamoid bone, that are otherwise difficult to visualize due to the natural forearm position of anteaters. Additionally, some fractures and physeal growth plates were identified in one juvenile individual. Further radiographic investigations should be conducted on anteaters to provide more tools for diagnosis, treatment, and rehabilitation of these animals.

Gradient-echo and spin-echo blood oxygenation level-dependent functional MRI at ultrahigh fields of 9.4 and 15.2 Tesla.

PURPOSE: Sensitivity and specificity of blood oxygenation level-dependent (BOLD) functional MRI (fMRI) is sensitive to magnetic field strength and acquisition methods. We have investigated gradient-echo (GE)- and spin-echo (SE)-BOLD fMRI at ultrahigh fields of 9.4 and 15.2  Tesla. METHODS: BOLD fMRI experiments responding to forepaw stimulation were performed with 3 echo times (TE) at each echo type and B0 in α-chloralose-anesthetized rats. The contralateral forelimb somatosensory region was selected for quantitative analyses. RESULTS: At 9.4 T and 15.2 T, average baseline T2* (n = 9) was 26.6 and 17.1 msec, whereas baseline T2 value (n = 9) was 35.7 and 24.5 msec, respectively. Averaged stimulation-induced ΔR2* was -1.72 s-1 at 9.4 T and -3.09 s-1 at 15.2 T, whereas ΔR2 was -1.19 s-1 at 9.4 T and -1.97 s-1 at 15.2 T. At the optimal TE of tissue T2* or T2 , BOLD percent changes were slightly higher at 15.2 T than at 9.4 T (GE: 7.4% versus 6.4% and SE: 5.7% versus 5.4%). The ΔR2* and ΔR2 ratio of 15.2 T to 9.4 T was 1.8 and 1.66, respectively. The ratio of the macrovessel-containing superficial to microvessel-dominant parenchymal BOLD signal was 1.73 to 1.76 for GE-BOLD versus 1.13 to 1.19 for SE-BOLD, indicating that the SE-BOLD contrast is less sensitive to macrovessels than GE-BOLD. CONCLUSION: SE-BOLD fMRI improves spatial specificity to microvessels compared to GE-BOLD at both fields. BOLD sensitivity is similar at the both fields and can be improved at ultrahigh fields only for thermal-noise-dominant ultrahigh-resolution fMRI.