Diagnostic assessment of two-dimensional shear wave elastography in relation to dimethyl arginine levels in dogs with chronic kidney disease.

BACKGROUND: In veterinary medicine, previous studies regarding the diagnostic performance of shear wave elastography (SWE) in chronic kidney disease (CKD) are not consistent with each other. Moreover, there has been no study evaluating the relationship between symmetric dimethyl arginine (SDMA) concentration and renal shear wave velocity (SWV) using two-dimensional SWE (2D SWE) in dogs with CKD. OBJECTIVES: This study aimed to evaluate the diagnostic capability of 2D SWE in dogs with CKD and to assess the relationship between renal SWV and SDMA concentration. METHODS: Dogs with healthy kidneys and dogs with CKD underwent 2D SWE and SDMA assay. Renal stiffness was estimated as renal SWV in m/s. RESULTS: SDMA concentration had a weak positive correlation with the left (r = 0.338, p = 0.022) and right renal SWV (r = 0.337, p = 0.044). Renal SWV was not significantly different between healthy kidney and CKD groups in the left (p = 0.085) and right (p = 0.171) kidneys. CONCLUSIONS: 2D SWE may could not distinguish between dogs with healthy kidney and dogs with early stage of CKD, but it would be useful for assessing the serial change of renal function in dogs.

B-mode ultrasonography and ARFI elastography of articular and peri-articular structures of the hip joint in non-dysplastic and dysplastic dogs as confirmed by radiographic examination.

BACKGROUND: Canine hip dysplasia is a common orthopedic disease in veterinary practice. The diagnosis is made by radiographic examinations that evaluate bone alterations associated with hip dysplasia. Although radiographic examination is the gold standard for diagnosis, it does not allow a detailed evaluation of soft tissues such as the joint capsule and periarticular muscles. This study aimed to evaluate the accuracy of B-mode ultrasonography and acoustic radiation force impulse (ARFI) elastography in assessing the joint capsule and periarticular muscles of dogs using the Orthopedic Foundation of Animals (OFA) classification and the distraction index (DI) in the early and late diagnosis of hip dysplasia. This study sought to propose a protocol for the ultrasonographic evaluation of the structures involved in canine hip dysplasia. METHODS: Radiographic and ultrasonographic evaluations were performed on 108 hip joints of 54 dogs. Thirty dogs were older than 2 years and 24 were aged between 4 and 10 months. RESULTS: It was verified that an increase in pectineus muscle stiffness (cutoff value > 2.77 m/s) by elastography in some dysplastic dogs and an increase in the thickness of the joint capsule (cutoff value > 0.9 mm) in B-mode ultrasonography, were associated with a distraction index > 0.5, with both having a positive correlation. In B-mode ultrasonographic evaluation, the presence of signs of degenerative joint disease, such as irregularities of the cranial edge of the acetabulum and femoral head, were associated with a distraction index > 0.5 in canines, with a specificity of 94%. In adult dogs, the findings of degenerative joint disease on ultrasound were associated with a diseased OFA classification (P < 0.05). Measurement of the joint capsule > 1.10 mm was diagnostic for dysplasia in unhealthy dogs by OFA. CONCLUSIONS: ARFI elastography has shown that the pectineus muscle may experience changes in stiffness in dysplastic animals. Additionally, changes in joint capsule thickness can be identified in B-mode in young and adult dogs with dysplastic joints, which contributes to the diagnosis of hip dysplasia.

Diagnostic utility of two-dimensional shear wave elastography in nephropathic dogs and its correlation with renal contrast-enhanced ultrasound in course of acute kidney injury.

Aims of our study were to evaluate the feasibility and diagnostic value of two-dimensional shear wave elastography in dogs with acute kidney injury, chronic kidney disease, and acute on chronic kidney disease, its correlation with renal functional (creatinine, urea), and prognostic parameters (serum calcium-phosphorus product, urinary output), and with contrast-enhanced ultrasound (qualitative and quantitative evaluation). The study was prospective. A group of healthy (Group A) and a group of nephropathic dogs (Group B) were included. Shear wave elastography was performed on the left kidney of the subjects of both groups; contrast-enhanced ultrasound was performed only in dogs with acute kidney injury and acute on chronic kidney disease. Sixty-four dogs were included (Group A, n=24; Group B, n=40). The renal stiffness values were significantly higher in Group B than Group A; optimal cut-off stiffness values for detection of renal pathology were: ≥1.51 m/sec (area under the curve, 0.84; 95% confidence interval 0.74-0.94) and ≥6.75 kPa (area under the curve, 0.84; 95% confidence interval 0.73-0.94). For contrast-enhanced ultrasound, a significant positive correlation was found between renal stiffness, area under the curve, and wash-out area under the curve values of cortex quantitative analysis. No correlations were found between renal stiffness and renal functional and prognostic parameters. Shear wave elastography showed diagnostic utility to detect renal abnormalities in dogs with acute kidney injury, chronic kidney disease and acute on chronic kidney disease, however, it could not differentiate between these different nephropathies.

Canine prostatic serum esterase and strain and 2D-shear wave sonoelastography for evaluation of normal prostate in dogs: Preliminary results.

Canine prostatic serum esterase (CPSE) is considered a useful tool to identify prostate disorders in dogs, with increasing interest in ultrasound (US)-based sonoelastography to non-invasively detect prostate disorders. Since no report is available about a possible correlation between these diagnostic tools, we aimed to investigate a possible correlation between strain elastography (SE) and 2D-shear wave elastography (SWE) and CPSE. Twenty-one dogs were included and, on each animal, CPSE was evaluated followed by a complete US examination and SE and 2D-SWE application. Healthy dogs were identified based on the CPSE results. All the dogs included were characterized by normal CPSE values (<52.3 ng/mL) and normal US prostate appearance. The prostate was characterized by intermediate stiffness with SE (pattern III - 84.7% for the left lobe and 79.27% for the right lobe) and softer than the abdominal wall (SR 0.6 for the left lobe and 0.56 for the right lobe), with low values for both m/s and kilopascals (kPa) for 2D-SWE, pointing that the healthy tissue is not hard. 2D-SWE results were, respectively, 13.51 ± 5.55 kPa and 2.31 ± 0.42 m/s for the left lobe and 18.05 ± 6.47 kPa and 2.39 ± 0.43 m/s for the right lobe. The significant difference between the right and left measurements expressed with kPa, not evidenced with m/s, can be considered indicative of m/s as the most reliable measurement to be considered regarding the prostate parenchyma. Even though no linear correlation was detected between CPSE and elastography values, these preliminary results evidence that the healthy prostates were characterized by a similar elastographic pattern, thus pointing that these techniques can be potentially useful to be applied in case of prostatic disorders to improve the accuracy of the final diagnosis in a non-invasive way.

Shear wave velocity values measured by 2D-shear wave elastography are not different between awake and anesthetized cats without clinically significant hepatic fibrosis.

Two-dimensional shear wave elastography (2D-SWE) is widely used as a noninvasive method to quantify liver stiffness. In humans, liver stiffness approximates histologic hepatic fibrosis. While histology is the gold standard for diagnosing liver disease, 2D-SWE may be a minimally invasive alternative to biopsy in feline patients. The objectives of this prospective, observational, crossover study were trifold: (1) to assess the feasibility of performing 2D-SWE in awake cats, (2) to determine whether anesthesia altered shear wave velocity (SWV) measurements, and (3) to correlate hepatic stiffness with histologically quantified hepatic fibrosis. Eleven healthy, purpose-bred cats underwent 2D-SWE in awake and anesthetized states. SWV measurements were compared with histologic fibrosis measurements obtained from liver biopsies during the anesthetic period. The mean velocities were not significantly different between awake (1.47 ± 0.18 m/s) and anesthetized (1.47 ± 0.24 m/s) cats. Premedication and anesthetic drugs did not impact mean SWV. There was a higher variability in the SWV values in the awake group. The data points were reliably replicated, with an interquartile range of 0.24 and 0.32 in anesthetized and awake groups, respectively. There was moderate agreement between observers (intraclass correlation coefficient = 0.66). All cats had clinically insignificant fibrosis. There was no correlation between the SWV measurements and the histological fibrosis values. This study demonstrates that 2D-SWE is feasible in awake cats and that the anesthetic protocol employed did not significantly alter mean SWV. This work is the first to histologically validate normal SWV values in cats and show that 2D-SWE cannot differentiate minimal differences in feline hepatic fibrosis.

Stiffness estimated by strain elastography reflects canine testicular spermatogenesis and histology.

Ultrasound elastography was proposed for the evaluation of testicular focal lesions, but no studies verified the agreement between the whole histological architecture of the testis and the stiffness measured by elastography. The present study explored the use of strain elastography in the evaluation of testis with normal or abnormal spermatogenesis, classified based on epididymal sperm attributes, and the consistency between elastographic parameters and the testicular histological feature. Strain elastography was performed during the routine andrological examination in 22 dogs presented for elective orchiectomy. Epididymal sperm attributes and testicular histology were analyzed after orchiectomy. Based on the epididymal sperm characteristics, testes were classified according to normal or abnormal spermatogenesis, and strain elastographic attributes were compared between groups. Possible correlations between strain elastography and histological features were also explored. Consistent with the literature in humans, testes with abnormal spermatogenesis were stiffer (mean strain elastographic index 3.6 ± 0.6) compared with normal testes (mean strain elastographic index 1.9 ± 0.2; P < 0.01). The strain elastographic index was negatively correlated with the area occupied by seminiferous tubules (Pearson's rho = -0.716; P = 0.0003), the mean diameter (Pearson's rho = -0.742; P = 0.0002), and thickness of the seminiferous tubule (Pearson's rho = -0.728; P = 0.0002). Surprisingly, no correlations were found between the area occupied by connective tissue in histological sections and elastographic attributes, suggesting that the increased stiffness was not related to the increased amount of connective tissue. This study demonstrated that strain elastography could be used to support the andrological examination, but measurements should be acquired in specific regions to be reliable.

Effectiveness of 2-dimensional shear wave elastography for noninvasive and reliable estimation of right atrial pressure in dogs with induced volume overload.

BACKGROUND: Two-dimensional shear wave elastography (2D-SWE) provides information on hepatic elastic modulus as shear wave velocity (SWV). HYPOTHESIS/OBJECTIVES: To assess SWV using 2D-SWE in dogs with induced volume overload, investigate the relationship between this information and right atrial pressure (RAP) measured by invasive right heart catheterization, and also evaluate the difference in SWV before and after diuretic administration. ANIMALS: Six healthy beagles. METHODS: Prospective experimental study. Right heart catheterization and 2D-SWE were performed in 6 anesthetized beagles at baseline and after the induction of volume overload. Volume overload was induced by IV hydroxyethyl starch 70/0.5 infusion (100 mL/kg/h). Furosemide (4-6 mg/kg, IV) was administered, and the SWVs were measured. RESULTS: Shear wave velocity showed a significant gradual increase during acute volume overload compared to baseline. SWV was significantly positively correlated with RAP (P < .0001, ρ = 0.9729). The area under the curve of SWV to predict RAP at >10, >15, and >20 mm Hg was 0.9896 (95% confidence interval [95% CI], 0.9690-1.000), 0.9907 (95% CI, 0.9701-1.000), and 0.9722 (95% CI, 0.9280-1.000), respectively. The SWV after diuretic use decreased significantly. CONCLUSIONS AND CLINICAL IMPORTANCE: Two-dimensional shear wave elastography might be useful for noninvasive and reliable estimation of RAP in dogs with acute volume overload and has potential as a quantitative biomarker for evaluating therapeutic response in dogs with right sided congestive heart failure.

Shear wave elastography evaluation of cats with chronic kidney disease.

Chronic kidney disease (CKD) is a major health condition in cats that can lead to poor quality of life and financial implications for therapy. Currently staging and identification of CKD is limited by diagnostic testing such as creatinine and urine-specific gravity, which do not change until late in the disease course. Other methods to evaluate CKD would be valuable in the clinical setting. Shear wave elastography is one novel ultrasound method, which has shown promise in identifying increases in tissue stiffness and identifying CKD in people. As CKD is often histologically characterized by tubulointerstitial fibrosis, shear wave elastography has the potential to identify CKD and differentiate between stages of CKD in cats. This prospective observational case-control study with 78 cats found no difference in shear wave velocities between groups (P = 0.33), a contradictory finding to one prior publication. There was no effect of weight (P = 0.65), nor the presence of mineralization (P = 0.31) or infarction (P = 0.52) on cortical shear wave velocities. There was a significant effect of age on shear wave velocity (P = 0.018) where velocities increased with age. The intraclass correlation coefficient was only moderate (0.62). Possible reasons for the difference in results between our work and that published prior, include differences in methodology and differences in instrumentation. Variability in measurements in our population may be due to the effects of respiratory motion or limitations in shear wave elastography software. As such, shear wave elastography is not currently recommended as a tool to evaluate CKD in cats and further work is necessary.

Correlating two-dimensional shear wave elastography of acute pancreatitis with Spec cPL in dogs.

BACKGROUND: Pancreatitis is a common disease in which 37% of dogs had evidence of acute or chronic pancreatitis at necropsy. Although biopsy is still the gold standard to diagnose acute pancreatitis, clinical data including ultrasonographic findings and measurement of canine serum pancreatic lipase immunoreactivity (cPLI) are used in routine. However, it may be insufficient in the diagnostic approach to acute pancreatitis. OBJECTIVES: To evaluate the clinical diagnostic feasibility of two-dimensional shear wave elastography (2D SWE) on canine acute pancreatitis for enhanced diagnostic confidence. METHODS: 2D SWE was used to assess pancreatic stiffness and determine the correlation between pancreatic shear wave velocity (SWV) and Spec cPL concentration in 31 dogs with healthy pancreas and 10 dogs with acute pancreatitis. RESULTS: The pancreatic SWV was significantly higher in the acute pancreatitis group (2.67 ± 0.20 m/s) than in the healthy pancreas group (2.30 ± 0.26 m/s; p < 0.05). The moderate positive correlation was found between the pancreatic SWV and Spec cPL concentration (95% confidence interval, 0.214-0.693; r = 0.489; p < 0.05). CONCLUSIONS: These results indicated that 2D SWE was feasible for assessing pancreatic stiffness in acute pancreatitis, and that pancreatic SWV using 2D SWE correlated with Spec cPL concentration. SWE could provide a quantitative measure of pancreatic stiffness, which can increase the accuracy of diagnosing acute pancreatitis in dogs. The 2D SWE can be used as a complementary imaging modality for diagnosing acute pancreatitis in dogs.

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.

Malignancy prediction of cutaneous and subcutaneous neoplasms in canines using B-mode ultrasonography, Doppler, and ARFI elastography.

BACKGROUND: Cutaneous and subcutaneous neoplasms are highly prevalent in dogs, ranging from benign to highly aggressive and metastatic lesions. The diagnosis is obtained through histopathology, however it is an invasive technique that may take a long time to obtain the result, delaying the beginning of the adequate treatment. Thus, there is a need for non-invasive tests that can help in the early diagnosis of this type of cancer. The aim of this study was to verify the accuracy of B-mode ultrasonography, Doppler, and ARFI elastography to predict malignancy in cutaneous and subcutaneous canine neoplasms. In addition, we aim to propose an ultrasonography evaluation protocol and perform the neoplasms characterization using these three proposed techniques. RESULTS: Twenty-one types of specific neoplasm were diagnosed, and using B-mode, we verified the association between heterogeneous echotexture, invasiveness, presence of hyperechoic spots, and cavity areas with malignancy. An increased pulsatility was verified in malignant neoplasms using Doppler (cut-off value > 0.93). When using the elastography, malignancy was associated with non-deformable tissues and shear wave velocity > 3.52 m/s. Evaluation protocols were proposed associating 4, 5, 6, or 7 malignancy predictive characteristics, and characterization was done for all tumors with at least two cases. CONCLUSIONS: We concluded that ultrasonography methods are promising and effective in predicting malignancy in these types of tumors, and the association of methods can increase the specificity of the results.

Shear wave elastography of lymph nodes in dogs with head and neck cancer: A pilot study.

Shear wave elastography (SWE) is a novel ultrasound imaging technique, used in human medicine to differentiate metastatic from non-metastatic lymph nodes (LNs) based on higher tissue stiffness. The objective of this pilot study was to evaluate whether canine metastatic LNs were stiffer compared to non-metastatic LNs. SWE of sentinel or regional LNs in dogs with head and neck cancer was performed. Ten elastograms of each LN were acquired. In each elastogram, mean, median, and maximum shear wave velocities (SWVs) were calculated in the most elastic region, the stiffest region, and the entire LN. The means of those SWVs for each region of each LN were subsequently calculated. Furthermore, a stepwise subsampling was performed to assess the effect of the number of acquired elastograms on the consistency of the classification of a LN as metastatic or not. Twenty-four LNs in 15 dogs with head and neck cancer were included, of which 10 LNs were metastatic. Metastatic medial retropharyngeal and mandibular LNs were successfully distinguished from non-metastatic LNs based on higher mean and median SWVs in the stiffest region and higher maximum SWVs in entire LNs. Furthermore, maximum SWVs in the stiffest region of mandibular LNs were higher in metastatic LNs compared to non-metastatic LNs. Downstream analyses demonstrated that at least eight elastograms were necessary to perform reliable analyses. This pilot trial demonstrated that SWE has potential to discriminate metastatic from non-metastatic LNs; however, LN status should be based on at least eight elastograms in future clinical trials.

Shear wave velocity measurements obtained in different regions are repeatable for presumed normal canine lymph nodes: A pilot study.

Shear wave elastography (SWE) has been applied as a noninvasive method for predicting regional lymph node (LN) metastases in human and veterinary patients. However, published studies describing standardized protocols and repeatability of this technique are currently lacking. The objective of this prospective, pilot, observer agreement study was to determine whether different shear wave velocity (SWV) measurements obtained in different regions of presumed normal canine LNs would be repeatable. Two imagers consecutively performed shear wave elastography of submandibular, superficial inguinal, and popliteal LNs in 10, clinically healthy adult dogs. Ten elastograms of each LN were acquired by each imager. In each adequate elastogram, three regions of interest (ROIs) were placed in the softest and stiffest region of the LN. Additionally, one ROI was drawn covering the entire LN. In each ROI, mean, median, and maximum SWVs were calculated. Mean values for the mean, median, and maximum SWVs varied from 2.33 to 3.10 m/s, 2.32 to 3.10 m/s, and 2.61 to 4.09 m/s, respectively. Intra- and interobserver agreements were acceptable. Superficial inguinal LNs demonstrated the highest intra- and interobserver agreement, followed by the popliteal and the submandibular LNs, respectively. Using the different measurements (mean, median, or maximum SWVs) had no significant effect on the intra- and interobserver variability, neither did the region (softest, stiffest, or entire LN). Findings indicated that all evaluated measurements and regions could be used to obtain reliable elastography data of presumed normal canine LNs. Clinical trials in dogs with cancer are necessary to compare SWVs of metastatic LNs with the reported SWVs and evaluate whether various measurements and regions can also be used in metastatic LNs.

Managing Reproduction Emergencies in the Field: Part 2: Parturient and Periparturient Conditions.

Selected conditions affecting broodmares are discussed, including arterial rupture, dystocia, foal support with ex utero intrapartum treatment, uterine prolapse, postpartum colic, the metritis/sepsis/systemic inflammatory response syndrome complex, and retained fetal membranes. Postpartum colic beyond third-stage labor contractions should prompt comprehensive evaluation for direct injuries to the reproductive tract or indirect injury of the intestinal tract. Mares with perforation or rupture of the uterus are typically recognized 1 to 3 days after foaling, with depression, fever, and leukopenia; laminitis and progression to founder can be fulminant. The same concerns are relevant in mares with retention of fetal membranes.

Elastosonographic features of the metacarpophalangeal joint capsule in horses.

BACKGROUND: Capsulitis leads to the release of inflammatory mediators in the joint, causing capsular fibrosis and osteoarthritis (OA). Strain elastosonography (SE) measures the elasticity of tissue by evaluating its strain in operator-dependent deformation. The aims of the study were to assess the feasibility, repeatability, and reproducibility of SE for imaging the distal attachment of the joint capsule (DJC) of metacarpophalangeal joints in sound horses (Group S) and in horses with metacarpophalangeal OA (Group P) and to evaluate differences in the elastosonographic patterns of these horses. After a whole lameness examination, fore fetlock DJCs were assigned to Group S and Group P and were thereafter examined by two operators using SE. Qualitative (i.e., colour grading score) and semi-quantitative (i.e., elasticity index (EI) and strain ratio (SR)) methods were used to evaluate the elastograms. The inter-rater reliability (IRR), intraclass correlation coefficient (intra-CC) and interclass correlation coefficient (inter-CC) were used to compare colour grading scores and the repeatability and reproducibility of EI and SR outcomes. The same parameters were compared between groups. P < 0.05 indicated a significant finding. RESULTS: Forty-one horses were included: 11 were in Group S and 30 were in Group P (16 with bilateral OA, 8 with left OA and 6 with right OA). IRR outcomes ranged from good to excellent. For transverse and longitudinal ultrasound scans, the colour grading score of Group S was significantly higher than the metacarpophalangeal DJCs of Group P. Both Inter-CC and intra-CC were higher in Group S than in Group P, with values always > 0.8. Significative differences in EI and SR were detected between groups and between Group S and the affected limb of Group P; values were lower in Group S than in Group P. CONCLUSIONS: SE can be a useful technique for evaluating DJCs, with good repeatability and reproducibility. DJCs appear softer in sound horses.

Extrahepatic biliary obstruction can interfere with hepatic fibrosis prediction using two-dimensional shear wave elastography in dogs.

Two-dimensional shear wave elastography (2D-SWE) can be used to quantitatively evaluate the elastic modulus of the liver as shear wave velocity (SWV), which can noninvasively predict clinically relevant hepatic fibrosis in both dogs and humans. However, extrahepatic biliary obstruction (EHBO), regardless of the presence of clinically relevant hepatic fibrosis, can influence SWVs in humans and thus may interfere with hepatic fibrosis prediction using 2D-SWE in dogs. The aim of this prospective, observational, and one-group pretest-posttest study is to investigate whether SWV measured by 2D-SWE displays a difference between dogs with and without EHBO. A total of 20 dogs were included (7 with EHBO and 13 with gallbladder pathology but no EHBO) that underwent preoperative SWV measurement using 2D-SWE. In all dogs, stages of hepatic fibrosis were evaluated histopathologically using a scoring scheme. In addition, postoperative SWVs in dogs with EHBO relieved via laparotomy were also evaluated. The median (range) SWVs in the dogs with and without EHBO were 1.91 (1.81-2.54) m/s and 1.57 (1.37-1.64) m/s, respectively. Although there was no significant difference in the histopathological hepatic fibrosis stages between the dogs with and without EHBO, the preoperative SWVs in the dogs with EHBO were significantly higher than in dogs without EHBO (P = .0004), and SWVs were found to decrease significantly after surgery (P = .0097). This study demonstrates that EHBO can increase the SWV of dogs without clinically relevant hepatic fibrosis and can interfere with the prediction of noninvasive hepatic fibrosis using 2D-SWE.

Strain elastography for the assessment of skin nodules in dogs.

BACKGROUND: Strain elastography (SE) is a modern imaging technology that provides an additional way of evaluating the changes in soft tissue elasticity caused by pathophysiological processes. Despite its widespread use in human medicine, only a few studies on the application of SE in veterinary medicine are available. OBJECTIVES: To evaluate the potential usefulness of SE as an integrative imaging model in the standard ultrasound technique to better discriminate between inflammatory and neoplastic skin nodules in dogs. ANIMALS: Fifty-one client-owned dogs with clinical evidence of single or multiple skin nodules detected during routine dermatological examination. METHODS AND MATERIALS: Margins, echogenicity, echo-structure, calcification and vascularisation of 65 skin nodules were assessed with ultrasound, and SE was used to score qualitative (E-score, E-index, E2) and semiquantitative (SR) parameters. A comparison of diagnostic yields with cytological and histological findings as the gold standard was performed. RESULTS: Mast cell and benign follicular tumours showed the highest E-scores and SRs among neoplastic nodules; statistically significant differences were not detected. Calcific and nonvascularised nodules showed significantly higher E-index values than the others. Overall, a negative correlation was observed between the longitudinal diameter of skin nodules and the qualitative elastic parameters. CONCLUSIONS AND CLINICAL IMPORTANCE: In this study, SE proved to be useful to identify only a subset of nodules such as mast cells and hair follicular tumours. Although evidence supporting the use of SE in evaluating skin nodules was demonstrated to below, indicators to guide further research were developed.

Point shear wave elastography of the liver in healthy adult cats.

OBJECTIVE: To evaluate stiffness of the liver parenchyma in healthy adult cats by means of point shear wave elastography (PSWE). ANIMALS: 18 client-owned adult (1- to 6-year-old) healthy cats. PROCEDURES: Echogenicity and echotexture of the liver parenchyma were assessed by means of conventional B-mode ultrasonography. The shear wave velocity (Vs) of the right and left portions of the liver were measured by means of PSWE. RESULTS: B-mode ultrasonography revealed no abnormalities in echotexture or echogenicity of the liver parenchyma in any cat. Mean (95% CI) Vs in the liver parenchyma was 1.46 m/s (1.36 to 1.55 m/s) for the right portion, 1.36 m/s (1.26 to 1.47 m/s) for the left portion, and 1.43 m/s (1.35 to 1.51 m/s) overall. The difference in mean Vs between the 2 portions of the liver was significant. No significant correlation was found between Vs and body weight or between Vs and the depth at which this variable was measured. CONCLUSIONS AND CLINICAL RELEVANCE: Quantitative PSWE of the liver was feasible in healthy adult cats. The obtained values for Vs may be useful for interpretation of and comparison with values measured in cats with liver disease. Additional research is needed to explore the potential usefulness of PSWE for diagnostic purposes.

Age-related change in shear elastic modulus of the thoracolumbar multifidus muscle in healthy Beagle dogs using ultrasound shear wave elastography.

BACKGROUND: Multifidus muscle stiffness decreases in patients with lumbar intervertebral disk herniation; however, age-related changes in humans have not been reported. OBJECTIVES: The reliability of ultrasound shear wave elastography in dogs, and changes in the shear elastic modulus of the thoracolumbar multifidus muscle with aging in dogs, were investigated. METHODS: Twelve beagle dogs were divided into 2 groups based on the age of onset of intervertebral disk herniation: young (aged not exceeding 2 years; 1.3 ± 0.6 years old, n = 5) and adult (4.9 ± 1.2 years old, n = 7). The shear elastic modulus of the multifidus muscle, from the thirteenth thoracic spine to the fourth lumbar spine, was measured using ultrasound shear wave elastography. The length, cross-sectional area and muscle to fat ratio of the multifidus muscle, and the grade of intervertebral disk degeneration, were assessed using radiographic and magnetic resonance imaging examinations. RESULTS: The length and cross-sectional area of the multifidus muscle increased caudally. In the young group, the shear elastic modulus of the multifidus muscle of the thirteenth thoracic spine was less than that of the third lumbar spine. In the adult group, the shear elastic modulus of the multifidus muscle of first and third lumbar spine was lower than that of the same site in the young group. CONCLUSIONS: Ultrasound can be used to measure shear wave elastography of the thoracolumbar multifidus in dogs. If the multifidus muscle stiffness decreases, we should consider age-related change.

Sonoelastography of Normal Canine Common Calcaneal Tendon: Preliminary Results.

Shear wave elastography (SWE) is a feasible and newly developed ultrasonographic technique which is able to assess elasticity of tissues. The aim of this work was to assess the feasibility of SWE on the normal canine common calcaneal tendon (CCT) evaluating the intra-operator repeatability and reproducibility of single measurements and stiffness of different anatomic CCT portions was examined. Tendons were first evaluated with B-mode ultrasound with a linear probe 8.5 to 10 MHz in longitudinal section with slight flexed tarsocrural joint and a gel-pad. Common calcaneal tendon was divided into three different anatomical regions. Shear wave elastography was performed in each region by two operators and quantitative evaluation (m/s and kPa) was performed on the most representative images. Region of interest (0.15 cm) was settled. Intraclass correlation coefficient (ICC) results were classified using the following scale: 0.00 to 0.20 = poor; 0.20 to 0.40 = fair; 0.40 to 075 = good; >0.75 = excellent. Ten adult dogs were enrolled. Intra-operator ICC values were >0.75 for both operators in every tendon portion. Inter-operator SWE ICC values for m/s measurements were 0.3, 0.61 and 0.61 for the enthesis, intermediate portion and the myotendinous junction respectively; for kPa measurements, values were respectively 0.3, 0.7 and 0.81. The three CCT portions were significantly different in stiffness (p-value < 0.001 for both m/s and kPa measurements). These preliminary results provide evidence that SWE is potentially appliable to assess mechanical properties of canine CCT affected by tendinopathies.