Ultrasonographic characterization of cervical lymph nodes in healthy dogs

Tomographic evaluation of the glands and lymph nodes of the cervical region in the crab-eating fox (Cerdocyon thous)

The present study aimed to determine references of normality of computed tomographic (CT) images of mandibular and parotid salivary glands (PSGs), medial retropharyngeal and mandibular lymph nodes and thyroid gland of 10 clinically healthy crab-eating foxes, Cerdocyon thous. The location, shape, homogeneity of the parenchyma, and length, height, width and pre- and post-contrast attenuation values were evaluated. The anatomical structures in the crab-eating foxes studied here presented anatomical landmarks similar to those described for domestic dogs, and showed a regular shape and homogenous parenchyma, except for the PSGs, that showed predominantly heterogeneous parenchyma. The thyroid gland topography in the crab-eating fox, though very similar, is not identical to the domestic dog and the presence of isthmus between the lobes was not detected. The values obtained from crab-eating foxes are within the normal range, although in the upper limits of dogs. There was a significant difference in the attenuation values between the right and left lobes of the thyroid gland, being greater in the left thyroid lobe. CT attenuation values ranges for this neotropical canid can be incorporated into routine staging procedures in the veterinary care of the crab-eating foxes. Furthermore, the CT images obtained were similar to those of healthy dogs, and the information obtained can be considered as initial tomographic references of normality in the cervical structures of the crab-eating fox, in order to aid in the diagnosis of future diseases that can affect this neotropical canid.

Ultrasonography and Sonoelastography Characteristics of Benign vs. Malignant Mesenteric Lymph Nodes in Cats: An Update

(1) Background: Strain elastography (SE) is an ultrasound-based technique able to non-invasively assess tissue elasticity, with malignant tissues being stiffer than normal tissues. The purpose of the study was to evaluate the diagnostic performance of SE to differentiate feline mesenteric benign and malignant lymph nodes (LNs) using a multivariate approach including both SE results and B-mode ultrasound and color Doppler findings. (2) Methods: Feline enlarged mesenteric LNs were evaluated using B-mode ultrasound, color Doppler ultrasonography, and SE. Short-to-long axis ratios, borders, echogenicity, hilum, vascular flow distribution, elastographic patterns, and strain ratios were recorded. Histological and/or cytological diagnosis was available for each LN. (3) Results: A total of 88 LNs were included, 46 (52.3%) benign and 42 (47.7%) malignant; in the benign group, 40 LNs had a diagnosis of reactive hyperplasia (group A) and 6 eosinophilic sclerosing lymphadenitis (group B), while in the malignant group 42 had a diagnosis of lymphoma (group C). The principal component analysis approach showed evidence that by combining B-mode- and color Doppler-based scores with SE scores, the three groups of LNs can be accurately distinguished. (4) Conclusions: Our results demonstrate that a multivariate sonographic approach combining B-mode ultrasound, color Doppler ultrasonography, and SE can accurately distinguish benign from malignant LNs, thus helping in the clinical advice of feline patients.

Retrospective characterisation and outcome of surgical treatment for cervical lymph node abscessation in 15 dogs

CASE HISTORIES

Medical records of a private referral hospital (Veterinary Emergency Clinic, Toronto, Canada) and a university teaching hospital (Louisiana State University, Baton Rouge, LA, USA) were reviewed, using the search terms lymphadenectomy, lymph node extirpation, cervical lymphadenitis, and lymph node abscessation. Dogs (n = 15) with a diagnosis of cervical lymph node abscessations confirmed through histopathology that underwent surgery for treatment from January 2015-May 2022 were included in the study. Long-term follow-up data was obtained by an in-person visit or telephone interview with each owner. Dogs that met the inclusion criteria were of various breeds with a median age of 6 (min 0.5, max 12) years. All cases presented with cervical swelling and lethargy, with inappetence and fever in 5/15 dogs. The range of duration of clinical signs prior to treatment was 1-3 weeks. Seven dogs were treated with a short course of antibiotics, with or without prednisone, without successful resolution, before referral.

CLINICAL FINDINGS

Diagnostic imaging using CT or cervical ultrasound revealed enlargement of unilateral mandibular and retropharyngeal lymph nodes with regional cellulitis and oedema in four dogs, enlargement of unilateral retropharyngeal lymph nodes with regional cellulitis in eight dogs, and a right ventral cervical abscess infiltrating the right medial retropharyngeal lymph nodes with oedema in one dog. Unilateral or bilateral cervical lymph node abscessation was diagnosed by lymphadenectomy and histopathology of affected lymph nodes. Bacterial cultures from samples of excised lymph nodes were positive in six cases.

TREATMENT AND OUTCOME

Cervical exploration and lymphadenectomy were performed in all cases. Thirteen dogs received antibiotics along with surgical treatment. Resolution was defined as absence of cervical swelling or enlarged lymph node(s) at the time of long-term follow-up (median 300 (min 240, max 1,072) days). Most patients had resolution of clinical signs following surgical excision of affected lymph nodes. Two dogs had complications including recurrence of clinical signs and development of open wounds following surgery. Their clinical signs resolved following additional administration of antibiotics.

CONCLUSIONS AND CLINICAL RELEVANCE

All dogs in this series had lymphadenectomy of abscessed lymph nodes and showed resolution of clinical signs with a favourable outcome. As 13/15 dogs also received antibiotics in conjunction with surgical treatment, appropriate use of antimicrobials may also play a role in treatment of this disease process.

Comparison of shear-wave velocities obtained with shear-wave elastography of various peripheral lymph nodes in healthy Beagles

OBJECTIVE

To compare shear-wave velocities (SWVs) with shear-wave elastography of various peripheral lymph nodes (LNs).

ANIMALS

11 healthy Beagles.

PROCEDURES

For each dog, bilateral mandibular, medial retropharyngeal, superficial cervical, axillary, superficial inguinal, and popliteal LNs were evaluated with shear-wave elastography in sagittal and transverse scanning planes. Depth of each lymph node was recorded, and intra- and interobserver reliability was determined.

RESULTS

SWVs for all LNs were significantly higher in the sagittal scanning plane, compared with those in the transverse scanning plane. The SWV of the most superficial LN, the mandibular LN, was significantly higher, compared with that for the other LNs, except for the medial retropharyngeal LN. The SWV of the deepest LN, the medial retropharyngeal LN, was as high as that for the mandibular LN. Intra- and interobserver reliability was excellent.

CONCLUSIONS AND CLINICAL RELEVANCE

SWVs for normal peripheral LNs of Beagles may serve as a reference to compare with those for other breeds and diseased LNs. Scanning plane, LN depth, and interfering tissues between the LN and the transducer may affect SWV. Shear-wave elastography may not be operator dependent.

Comparison of shear-wave velocities obtained with shear-wave elastography of various peripheral lymph nodes in healthy Beagles

OBJECTIVE

To compare shear-wave velocities (SWVs) with shear-wave elastography of various peripheral lymph nodes (LNs).

ANIMALS

11 healthy Beagles.

PROCEDURES

For each dog, bilateral mandibular, medial retropharyngeal, superficial cervical, axillary, superficial inguinal, and popliteal LNs were evaluated with shear-wave elastography in sagittal and transverse scanning planes. Depth of each lymph node was recorded, and intra- and interobserver reliability was determined.

RESULTS

SWVs for all LNs were significantly higher in the sagittal scanning plane, compared with those in the transverse scanning plane. The SWV of the most superficial LN, the mandibular LN, was significantly higher, compared with that for the other LNs, except for the medial retropharyngeal LN. The SWV of the deepest LN, the medial retropharyngeal LN, was as high as that for the mandibular LN. Intra- and interobserver reliability was excellent.

CONCLUSIONS AND CLINICAL RELEVANCE

SWVs for normal peripheral LNs of Beagles may serve as a reference to compare with those for other breeds and diseased LNs. Scanning plane, LN depth, and interfering tissues between the LN and the transducer may affect SWV. Shear-wave elastography may not be operator dependent.

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.

Ultrasonographic Algorithm for the Assessment of Sentinel Lymph Nodes That Drain the Mammary Carcinomas in Female Dogs

The status of sentinel lymph nodes (SLNs) is decisive in staging, prognosis, and therapeutic approach. Using an ultrasonographic examination algorithm composed of B-mode, Doppler technique, contrast-enhanced ultrasound (CEUS) and elastography, this study aimed to determine the diagnostic performance of the four techniques compared to histopathological examination. 96 SLNs belonging to 71 female dogs with mammary gland carcinomas were examined. After examinations, mastectomy and lymphadenectomy were performed. Histopathological examination confirmed the presence of metastases in 54 SLNs. The elasticity score had the highest accuracy-89.71%, identifying metastases in SLNs with 88.9.9% sensitivity (SE) and 90.5% specificity (SP), ROC analysis providing excellent results. The S/L (short axis/long axis) ratio showed 83.3% SE and 78.6% SP as a predictor of the presence of metastases in SLN having a good accuracy of 81.2%. On Doppler examination, the resistivity index(RI) showed good accuracy of 80% in characterizing lymph nodes with metastases versus unaffected ones; the same results being obtained by CEUS examination. By assigning to each ultrasonographic parameter a score (0 or 1) and summing up the scores of the four techniques, we obtained the best diagnostic performance in identifying lymph node metastases with 92.2% accuracy. In conclusion, the use of the presented algorithm provides the best identification of metastases in SLNs, helping in mammary carcinoma staging and appropriate therapeutic management.