Contrast-enhanced ultrasonography improves detection of the perfusion and vascularity of organs. Its main indication is the assessment of focal lesions in the liver and spleen, particularly with regard to differentiating between benign and malignant processes. Evidence suggests that contrast-enhanced ultrasonography may be a valuable alternative to invasive diagnostic procedures such as fine-needle aspiration and core biopsy.

Microbubbles have shown potential as intralymphatic ultrasound contrast agents while nanoparticle-loaded microbubbles are increasingly investigated for ultrasound-triggered drug and gene delivery. To explore whether mRNA-nanoparticle loaded microbubbles could serve as theranostics for detection of and mRNA transfer to the lymph nodes, we investigate the behavior of unloaded and mRNA-loaded microbubbles using contrast-enhanced ultrasound imaging after subcutaneous injection in dogs. Our results indicate that both types of microbubbles are equally capable of rapidly entering the lymph vessels and nodes upon injection, and novel, valuable and detailed information on the lymphatic structure in the animals could be obtained. Furthermore, additional observations were made regarding the dynamics of microbubble lymph node uptake. Importantly, neither the microbubble migration distance within the lymphatics, nor the observed contrast signal intensity was influenced by mRNA-loading. Although further optimization of acoustic parameters will be needed, this could represent a first step towards ultrasound-guided, ultrasound-triggered intranodal mRNA delivery using these theranostic microbubbles.

To describe the contrast-enhanced ultrasonographic appearance of various focal, space-occupying renal lesions and determine its value in their detection and characterization. Following baseline B-mode sonography of 15 dogs and one cat with renal space-occupying lesion(s), contrast-enhanced sonography was performed. The resulting images were evaluated qualitatively using conspicuity and number of lesions, and enhancement patterns were assessed during early arterial and late corticomedullary phases. Renal lesions were malignant in the cat (renal cell carcinoma) and 10 dogs (four renal cell carcinoma, two histiocytic sarcoma, one B-cell lymphoma, two hemangiosarcoma metastasis, one ch emodectoma metastasis) and benign in five dogs (two abscesses, one traumatic hematoma, one idiopathic hematoma, one hemorrhagic/necrotic nodule). Substantial overlap was present regarding the baseline sonographic features of benign vs. malignant lesions. With contrast-enhanced sonography, all renal cell carcinomas were characterized by large tortuous arteries, sometimes enhancing slightly earlier than vessels in the surrounding normal kidney. During the late corticomedullary phase, renal cell carcinomas had intense homo- or heterogeneous, iso- or slightly hypoechoic enhancement, which decreased progressively. Compared with renal cell carcinoma, histiocytic sarcoma and lymphoma had smaller and less obvious arteries, and an earlier loss of enhancement during the late phase. All hemangiosarcoma metastases appeared as nonenhancing nodules during the early arterial and late corticomedullary phases of enhancement, and additional lesions were detected. Histiocytic sarcoma and benign lesions had increased conspicuity with baseline sonography. The descriptions provided herein will be valuable as more work is done to establish the role of contrast-enhanced sonography in the assessment of renal lesions.

Drawing on current literature relating to ultrasonographic examination of feline kidneys, the aim is to summarise ultrasonographic technique, anatomy and changes associated with renal and perirenal diseases.

Objectives of this study were to evaluate glomerular filtration rate (GFR), renal structural changes and proteinuria in aged Beagle dogs before and after hydrocortisone (HC) administration. Eleven Beagle dogs ≥10 years old were treated with either hydrocortisone (HC group, n = 6) or placebo (control group, n = 5). Urinary markers, GFR and kidney biopsies were evaluated before (T0), during (T16 wks) and after discontinuing HC administration (T24 wks). Results indicate that HC administration causes a significant increase in GFR. At all time points except T16 wks, proteinuria was higher in the control group than in the HC group, and there was no significant difference in urinary markers between groups. At T16 wks, proteinuria, urinary albumin-to-creatinine (c) ratio, immunoglobulin G/c and retinol-binding protein/c were higher compared to baseline in the HC group. At T0, rare to mild renal lesions were detected in all HC dogs and rare to moderate changes in all control dogs. Glomerulosclerosis progressed in both groups until T24 wks. Tubular atrophy was detected in three HC dogs at T16 wks and T24 wks, but also in five control dogs throughout the study. At every time point, five HC dogs and all control dogs had rare to moderate interstitial inflammation. Rare to mild interstitial fibrosis was found in up to three HC dogs at T16 wks and T24 wks, and severe fibrosis in one HC dog at T24 wks. Up to four control dogs had rare to mild fibrosis at all time points. These findings indicate that clinically healthy, aged Beagle dogs may have considerable renal lesions and proteinuria, which could have implications for experimental or toxicological studies. Additional research is needed to elucidate glucocorticoid effects on renal structure, but functional changes such as hyperfiltration and proteinuria warrant attention to kidney function of canine patients with Cushing's syndrome or receiving exogenous glucocorticoids.