Ultrasonographic evaluation of tracheal collapse in dogs

Tracheal ultrasonography was performed to measure the width of the tracheal ring shadow and to assess the clinical relevance of these measurements for identifying tracheal collapse. The first tracheal ring width (FTRW) and thoracic inlet tracheal ring width (TITRW) were measured on both expiration and inspiration. The mean of the FTRW width (129 dogs) was greater in expiration (10.97 ± 1.02 mm, p = 0.001) than that in inspiration (9.86 ± 1.03 mm). For 51 normal dogs, the mean of the TITRW width was greater in expiration (9.05 ± 1.52 mm, p = 0.001) than in inspiration (8.02 ± 1.43 mm). For 78 tracheal collapse dogs, the mean of the TITRW width was greater in expiration (15.89 ± 1.01 mm, p = 0.001) than in inspiration (14.85 ± 1.17 mm). The TITRW/FTRW ratio of the normal dogs was higher (p = 0.001) in expiration (0.81 ± 0.09) than that in inspiration (0.79 ± 0.10). When compared between the normal and tracheal collapse dogs, the TITRW/FTRW ratio was also increased (p = 0.001) both in expiration (1.54 ± 0.09) and inspiration (1.47 ± 0.08), respectively. Based on these results, the cutoff level of the TITRW/FTRW ratio was statistically analyzed according to the receiver operating characteristic curve and it could be set at 1.16 in expiration and at 1.13 in inspiration. We have demonstrated that tracheal ultrasonography is a useful technique for the evaluation of tracheal collapse and it can be a supportive tool together with the radiographic findings for making the correct diagnosis.     

Ultrasonographic findings of pylorogastric intussusceptions in two dogs

A Yorkshire terrier (case 1) and a Miniature Schnauzer (case 2) were diagnosed with pylorogastric intussusceptions (PGIs). Both cases showed acute vomiting and had previous histories of laparotomy. In case 1, the invaginated pyloric wall was thickened unevenly containing multiple hypoechoic areas and had indistinct wall layering on ultrasonography. PGI with diffuse gastric edema and necrosis was confirmed on laparotomy. The dog recovered completely after gastrectomy and a Y-U plasty. Case 2 had uniformly thickened walls of invaginated gastric pylorus with the distinct wall layering. PGI was reduced spontaneously the next day.     

Ultrasonographic evaluation of vitreous degeneration in normal dogs.

Vitreous degeneration is common in dogs and may be associated with cataract formation. Vitreous degeneration may be identified using B-mode ultrasonography and appears as multiple, small, motile, point-like echoes within the vitreous cavity. In humans, vitreous degeneration has also been observed in normal aging eyes but the incidence of vitreous degeneration in dogs without cataract has not previously been documented. The purpose of this study was to describe the ultrasonographic appearance of vitreous degeneration and to investigate its incidence in a population of dogs without cataract or other apparent eye disease. The eyes of 62 dogs were evaluated as part of a prospective study. All dogs underwent ophthalmological and ultrasonographic examinations and vitreal changes were graded on ultrasonography using a predetermined grading scheme. Vitreous degeneration was found in 20% (23/114) of the eyes on ultrasonographic examination but in only 8% (9/114) of eyes on direct ophthalmoscopy. Sensitivity and specificity of ophthalmoscopy using ultrasonography as a gold standard were respectively, 39% and 100%. Vitreal syneresis and asteroid hyalosis could be distinguished according to their ultrasonographic characteristics. The probability of having vitreous degeneration increased with the age of the dog (odds ratio = 6.7 for dogs of 7 + years compared with 0-6 years) and also increased in females compared with males (odds ratio = 3.6). Vitreous degeneration, especially mild vitreal syneresis, is not uncommon in normal dogs; it was shown to be an age-related condition and its significance should not be overinterpreted on ocular ultrasonography.     

Ultrasonographic examination of the carpal region in cattle--normal appearance

The carpal region was examined ultrasonographically in 18 healthy cattle (14 cows, 4 bull calves) and five bovine cadavers in order to determine the normal appearance of the carpal soft tissues using 7.5 MHz linear transducers.The course of the echogenic flexor and extensor tendons over the carpus and the joint spaces interposed between the articular bone surfaces were successfully imaged in all carpi. The palmar vessels were easily visualized in live animals. The lumina of carpal tendon sheaths and the boundaries of the carpal joint pouches could not be defined. Small anechoic fluid filled areas were visualized only at the level of the joint spaces. After experimental filling, the distended synovial cavities were imaged as well demarcated anechoic areas. The cross-sectional diameters of the extensor tendons, width of the palmar joint pouches and intraluminal diameters of the palmar vessels were measured.The results presented serve as reference data for ultrasonographic investigation of disorders of the bovine carpus.     

Ultrasonographic and radiographic assessment of uncomplicated secondary fracture healing of long bones in dogs and cats

OBJECTIVES: To evaluate the use of ultrasonography (US) to detect bone healing in uncomplicated diaphyseal fractures of dogs and cats, and to compare these observations with detection of healing by radiography (RG). STUDY DESIGN: Clinical study. ANIMALS: Dogs (33) and cats (11). METHODS: RG and brightness mode US were used to follow uncomplicated secondary fracture healing. Fractures were examined at admission and then every 2-4 weeks until healed or implant removal. Temporal differences in definitive detection of healed fracture by imaging technique were examined by species, patient age, bone, and fracture type. RESULTS: US images obtained during uncomplicated secondary fracture healing were consistent with images of fracture healing described in humans. Mean time to US diagnosis of a healed fracture (mean 46 days) was significantly shorter than by RG (mean 66 days). Mean time until diagnosis of a healed fracture (US and RG) did not differ significantly between open and closed treatment. Patients 36 months (n=11), but there was no significant difference between the latter 2 groups. Diagnosis of a healed simple fracture by US was significantly quicker than for a comminuted fracture (P<.05), but no difference was noted when using RG. CONCLUSIONS: US can be used to evaluate secondary fracture healing in biologically treated fractures in dogs and cats. US permits detection of a healed fracture earlier than RG. CLINICAL RELEVANCE: Earlier diagnosis of a healed fracture by US can prevent unnecessarily long limb immobilization and allow earlier dynamization.     

Computed tomographic evaluation of cervical vertebral canal and spinal cord morphometry in normal dogs

The height, width, and cross-sectional area of the vertebral canal and spinal cord along with the area ratio of spinal cord to vertebral canal in the cervical vertebra were evaluated in images obtained using computed tomography (CT). Measurements were taken at the cranial, middle, and caudal point of each cervical vertebra in eight clinically normal small breed dogs (two shih tzu, two miniature schnauzers, and four mixed breed), 10 beagles, and four German shepherds. CT myelography facilitated the delineation of the epidural space, subarachnoid space, and spinal cord except at the caudal portion of the 7th cervical vertebra. The spinal cord had a tendency to have a clear ventral border in the middle portion of the vertebral canal and lateral borders near both end plates. The height, width, and area of the vertebral canal and spinal cord in the cervical vertebra were increased as the size of dog increased. However, the ratio of the spinal cord area to vertebral canal area in the small dogs was higher than that of the larger dogs. Results of the present study could provide basic and quantitative information for CT evaluation of pathologic lesions in the cervical vertebra and spinal cord.     

Medial plating for carpal panarthrodesis

OBJECTIVE: To describe a technique for carpal panarthrodesis using a medially applied dynamic compression plate (DCP) and to evaluate outcome. STUDY DESIGN: Retrospective study. ANIMALS: Nine dogs with 10 carpal joint injuries. METHODS: Medical records of dogs that had carpal panarthrodesis by medial application of a DCP were reviewed. Signalment, cause and type of injury, preoperative treatment, operative technique, and postoperative clinical and radiographic outcome were retrieved. RESULTS: Screw loosening in the metacarpal bones required surgical revision in 3 dogs. The plate was removed because of lick dermatitis in another dog. No complications were observed in 6 arthrodeses. All dogs were subsequently sound. CONCLUSIONS: Medial application of a DCP is a reliable, reproducible method for carpal panarthrodesis. The load on the edge of the plate provides an increased area moment of inertia of the plate, enhancing it resistance to bending forces. Because of the valgus standing position of the canine carpus, dynamic compression is achieved. The DCP is secured to 1-3 metacarpal bones and loosening of the implant and bone fractures are expected to occur less frequently. CLINICAL RELEVANCE: Medial plating for carpal panarthrodesis is a valid alternative method that can be used in dogs with injuries to the carpus for which panarthrodesis of the carpal joint is indicated.     

Ultrasonographic guided block of the median nerve

Median nerve anaesthesia is sometimes indicated in the diagnosis of forelimb lameness in the horse in conjunction with the ulnar nerve block, but the localisation of the nerve to perform a precise deposition of the anaesthetic solution around and close to the nerve is difficult to achieve using the conventional blind technique. The objectives of this paper are to describe the ultrasonographic anatomy of the median nerve and the technique for performing an ultrasound-guided anaesthetic block of the nerve. The median nerve is imaged using a microconvex (or linear) probe in transverse section performed proximally to the chestnut on the medial aspect of the forearm. Distribution of the anaesthetic solution around the nerve is done by initially inserting the needle caudally and then cranially to the nerve and injecting 4–6 mL at each site. Control of the needle penetration avoids erroneous intravascular or intramuscular injections or sudden horse reaction. Ultrasound-guided injection has the potential to safely and accurately block the median nerve.     

Ultrasonographic identification of vascular invasion by adrenal tumors in dogs

Adrenalectomy is the treatment of choice for adrenal tumors that are producing adverse clinical signs. Surgical planning prior to adrenalectomy is aided by identifying tumors with invasion into adjacent vessels or the presence of a tumor thrombus extending into the caudal vena cava. In this paper, we evaluated the sensitivity and specificity of ultrasound in determining if vascular invasion or tumor thrombus is present. Thirty-four dogs with 36 adrenal tumors were reviewed retrospectively. Overall, 36% of tumors had vascular invasion. Abdominal ultrasound was 100% sensitive and 96% specific in identifying the presence of a tumor thrombus in the caudal vena cava. The sensitivity and specificity was 76% and 96%, respectively, when all forms of vascular invasion were evaluated and included patients with vascular wall invasion without concurrent thrombus. Abdominal ultrasound is a good screening tool for identifying vascular invasion or tumor thrombus associated with adrenal tumors in dogs.     

Evaluation of the potential efficacy of an ultrasound-guided adductor canal block technique in dog cadavers

Objective

To evaluate an ultrasound-guided technique for adductor canal (AC) block by describing the distribution of methylene blue around the AC, popliteal fossa, saphenous, tibial and common fibular nerves in dog cadavers.

Treatment of a second carpal bone fracture by removal under ultrasonographic guidance in a horse

OBJECTIVE: To report an unusual 2nd carpal bone (C2) slab fracture and its treatment, using an ultrasonographically assisted, minimally invasive arthrotomy technique, for fragment removal. STUDY DESIGN: Case report. ANIMALS: An 11-year-old crossbred Warmblood gelding. METHODS: A bone fragment, spanning the height of C2, identified on the palmaromedial aspect of C2 was demarcated intraoperatively using ultrasonographically guided needles and removed by arthrotomy. RESULTS: Fracture fragment removal was achieved using a small, ultrasonographically guided arthrotomy. The horse has become sound after treatment and returned to the previous level of pleasure riding activity. CONCLUSIONS: Perioperative ultrasonography was used to delineate and facilitate removal of an unusual slab fragment of C2, through a minimally sized arthrotomy. Despite the presence of pancarpal osteoarthritis and partial involvement of the medial collateral ligament, the prognosis appeared to be satisfactory for this pleasure riding horse. CLINICAL RELEVANCE: Ultrasonographic guidance may be used to optimize the approach to C2 articular bony fragments that may not be observed using arthroscopy.     

Traumatic neuroma of the medial palmar nerve as a possible cause of a severe gait abnormality in a Warmblood riding horse

This paper describes the history, examination and clinical findings in a riding horse with a gait abnormality. The lesion was localised to the carpal area of one of the forelimbs, but could not be properly characterised until post mortem examination, when a diagnosis of a traumatic neuroma of the medial palmar nerve could be reached. Thus, the most plausible explanation for the gait abnormality of the horse was found in the peripheral nervous system.     

Ocular complications of persistent hyperplastic primary vitreous in three dogs

Persistent hyperplastic primary vitreous (PHPV) syndrome associated with either severe ocular complications or multiple ocular lesions was diagnosed in three young dogs, a Samoyed, a Spanish Pachon, and a mixed breed dog. Due to opacification of the anterior ocular structures, B-mode and color-flow Doppler ultrasonography were performed to aid diagnosis. The Samoyed presented with unilateral hyphema; the Spanish Pachon presented with unilateral secondary glaucoma associated with uveitis and hyphema OD and leucocoria OU; and the mixed breed presented with bilateral leucocoria. B-mode ultrasonography of the Samoyed revealed a subcapsular cataract and a hyperechoic tubular structure attached from the optic disk to the posterior lens capsule. In the Spanish Pachon B-mode ultrasonography of the right eye indicated microphakia, cataract formation, and a retrolental mass with a thin hyperechoic strand stretching from the optic disk to the posterior lens; and for the right eye cataract formation, PHPV, retinal detachment, and vitreous hemorrhage. In the mixed breed dog, B-mode ultrasonography of both eyes indicated microphthalmia, retrolental mass, and hyperechoic lenses. By color-flow Doppler imaging, blood flow was present in the retrolental mass of the right eye suggesting a persistent hyaloid artery.     

Evaluating the correlation between adrenal gland dimensions and aortic diameter in healthy dogs

In the present study, the relationship of normal adrenal dimensions with weight, aortic diameter, age and sex was evaluated. Moreover, a formula for estimating the normal dimensions of adrenal gland was provided. Thirty‐two intact adult dogs that were considered healthy based on history, physical examination, routine blood works and specific adrenal tests as well as absence of any abnormal ultrasonographic findings were included. Adrenal glands and abdominal aorta were imaged in the sagittal plane by ultrasound. Length, maximal height of the cranial and caudal poles, area and circumference of the left and right adrenal glands and also the internal diameter of the abdominal aorta were measured. Analysis showed that there is a positive correlation between the adrenal gland dimensions and weight and aortic diameter. The ratio of adrenal gland dimensions and the aortic diameter was calculated, but this ratio showed a great amount of variability in tandem with a significant correlation to the weight; Meaning that the ratio of the adrenal gland dimensions to the aortic diameter was not a reliable index for evaluating the size of the normal adrenal gland in animals with different weights. Therefore, we used the weight along with adrenal measurements in a linear regression model, and then, we were able to estimate the adrenal gland dimensions in different weights. Knowing the relationship of normal adrenal dimensions with the indices such as weight, age, sex and diameter of abdominal aorta can help the clinicians to diagnose the adrenal gland diseases.     

Accuracy of sonographic diagnosis of pneumoperitoneum using the enhanced peritoneal stripe sign in beagle dogs

The objective of this study was to evaluate the feasibility and accuracy of estimating the smallest amount of abdominal free gas detectible in a large population of beagles by ultrasonography. Healthy dogs were randomly divided into three groups: group A that received 0.1 mL of air injected into the peritoneal cavity, group B that received 0.2 mL of air injected into the peritoneal cavity, and group C that received 0.5 mL of intraperitoneal air. Randomly, some dogs in each group did not receive air injection for the negative control. All ultrasonographic procedures were performed by individuals blinded to group assignments and the presence of intraperitoneal air. The minimum volume of consistently detectable air with good accuracy and reliability was 0.2 mL. Results of the study demonstrated that the enhanced peritoneal stripe sign (EPSS) can verify cases of pneumoperitoneum if more than 0.2 mL of intra-abdominal free gas is present The EPSS is a reliable and specific ultrasonographic characteristic for diagnosing pneumoperitoneum in dogs.     

Tenosynovitis of the carpal sheath of the digital flexor tendons associated with tears of the radial head of the deep digital flexor: observations in 11 horses

Reasons for performing study: Tears of the radial head of the deep digital flexor (DDF) have not previously been documented. Objectives: To describe the presentation, clinical, ultrasonographic and tenoscopic features associated with tears of the radial head of the DDF and to report the results of treatment. Hypotheses: Tears of the radial head of the DDF cause lameness and distension of the carpal sheath of the digital flexor tendons. Removal of disrupted tissue that is extruded into the sheath can result in clinical resolution and restoration of function. Methods: Case records and diagnostic images of horses in which tearing of the radial head of the DDF was diagnosed were reviewed retrospectively and follow‐up information obtained. Results: Eleven cases were identified. Clinical, ultrasonographic and tenoscopic commonality was recorded and treatment techniques were documented. All cases returned post operatively to pre‐injury levels of work. Conclusion: Tearing of the radial head of the DDF is a clinical entity with consistent diagnostic features. Tenoscopic removal of the torn tissue is associated with a good outcome. Potential relevance: Clinicians evaluating lame horses should include tearing of the radial head of the DDF as a differential diagnosis in animals with distended carpal sheaths. Tenoscopic surgery is a recommended treatment.     

Prospective evaluation of pancarpal arthrodesis for carpal injuries in working dogs in New Zealand,using dorsal hybrid plating

Abstract

AIM: To determine whether working dogs in New Zealand with carpal injuries and treated with unilateral pancarpal arthrodesis (PCA), using a dorsal hybrid-plating method, are able to return to satisfactory working ability.

METHODS: Fourteen working dogs presented to the Veterinary Specialist Group (VSG) and the Massey University Veterinary Teaching Hospital (MUVTH) with carpal injuries were prospectively treated using dorsal hybrid plating. Dogs were eligible if actively involved in farm, hunting or police work. Dogs had a standardised PCA surgical procedure performed, and similar instructions for post-operative care were provided. Dogs were re-evaluated clinically and radiographically at 6 weeks, 6 months, and 12 months after surgery. A questionnaire was completed by 12 owners, to assess each dog's working ability.

RESULTS: Twelve months following arthrodesis, 10/12 (83%) dogs could perform most or all duties normally. Eleven owners (92%) reported that the result of the surgery met their expectations, and nine owners (75%) were very satisfied with the outcome of the surgery. No owners were disappointed or very disappointed with the surgical outcome. Post-operative complications requiring surgical removal of the implant occurred in three (25%) dogs.

CONCLUSIONS: Unilateral PCA using a standardised surgical procedure and dorsal hybrid plating of carpal injuries has a good prognosis for working dogs in New Zealand to return to work.

CLINICAL RELEVANCE: These results may allow veterinarians to provide a more accurate prognosis to owners of working dogs that have debilitating carpal injury     

Correlation of cytologic and histopathologic findings with perinodal echogenicity of abdominal lymph nodes in dogs and cats

Abdominal lymphadenopathy in dogs and cats is routinely investigated with ultrasound. As the determination between benign and neoplastic etiologies of lymphadenopathy affects patient management, specific sonographic characteristics associated with both benign and neoplastic lymph nodes have been suggested. However, a significant overlap between these characteristics exists, necessitating a cytologic or histopathologic diagnosis in most instances. The objectives of this retrospective, cross‐sectional study were to evaluate whether echogenicity of perinodal fat could be a discriminator between benign and neoplastic abdominal lymphadenopathy and to assess if additional sonographic features associated with malignancy could be identified in lymph nodes with hyperechoic perinodal fat. Small animal patients (257 dogs and 117 cats) with sonographic evidence of abdominal lymphadenopathy and a cytological or histopathological diagnosis were evaluated for differences in the proportions of sonographic features between benign and neoplastic groups. Greater maximum long axis diameter (in dogs and cats) and a greater number of abnormal lymph nodes (in cats) were associated with malignancy in lymph nodes with hyperechoic perinodal fat. Canine lymph nodes with round cell neoplasia were significantly more likely to have hyperechoic perinodal fat. Lymph nodes affected with other neoplasia or with lymphadenitis were equally likely to have normal or hyperechoic perinodal fat. Reactive lymph nodes were significantly less likely to have hyperechoic perinodal fat in both species. These results suggest that though echogenicity of perinodal fat is a nonspecific finding, abdominal lymph nodes with hyperechoic perinodal fat are less likely to be reactive and sampling of these lymph nodes may be indicated.