Evaluation of Renal Perfusion in Hyperthyroid Cats before and after Radioiodine Treatment

Abstract

BackgroundHyperthyroidism and chronic kidney disease (CKD) are common in elderly cats. Consequently, both diseases often occur concurrently. Furthermore, renal function is affected by thyroid status. Because changes in renal perfusion play an important role in functional renal changes in hyperthyroid cats, investigation of renal perfusion may provide novel insights.ObjectivesTo evaluate renal perfusion in hyperthyroid cats with contrast‐enhanced ultrasound (CEUS).AnimalsA total of 42 hyperthyroid cats was included and evaluated before and 1 month after radioiodine treatment.MethodsProspective intrasubject clinical trial of contrast‐enhanced ultrasound using a commercial contrast agent (SonoVue) to evaluate renal perfusion. Time‐intensity curves were created, and perfusion parameters were calculated by off‐line software. A linear mixed model was used to examine differences between pre‐ and post‐treatment perfusion parameters.ResultsAn increase in several time‐related perfusion parameters was observed after radioiodine treatment, indicating a decreased blood velocity upon resolution of the hyperthyroid state. Furthermore, a small post‐treatment decrease in peak enhancement was present in the renal medulla, suggesting a lower medullary blood volume.Conclusions and Clinical ImportanceContrast‐enhanced ultrasound indicated a higher cortical and medullary blood velocity and higher medullary blood volume in hyperthyroid cats before radioactive treatment in comparison with 1‐month post‐treatment control.

Comparison of free thyroxine measurement by chemiluminescence and equilibrium dialysis following 131I therapy in hyperthyroid cats

“…Fifty client-owned previously reported hyperthyroid cats presented for 131 I treatment were prospectively enrolled in this study (Figure 1). 7 Five cats were excluded at T0 because of owner non-compliance (n = 1), congestive heart failure (n = 1), thyroid carcinoma with lung metastasis (n = 1) and insufficient sampling due to aggressive behaviour (n = 2). Of the 45 included cats at T0 and T1, 21 were castrated males, 23 were spayed females and one was an intact female.…”

“…Fifty client-owned, previously reported hyperthyroid cats presented for treatment with 131I at the Small Animal Department of Ghent University were prospectively enrolled in this study. 7 Local ethical committee approval (Ghent University EC 2017/72) and the signed informed consent of the owners was obtained. The cats were diagnosed with hyperthyroidism based on clinical signs, increased serum TT4 concentration (at the referring veterinarian) and increased technetium uptake in one or both thyroid glands on scintigraphic scan (thyroid:salivary ratio >1).…”

A specific immunoassay for detection of feline kidney injury molecule 1

“…Hyperthyroidism results in tachycardia, increased cardiac output, decreased vascular resistance and increased renal perfusion, with the degree of change likely influenced by the severity and duration of hyperthyroidism. 40–42 Up to 50% of cats with hyperthyroidism have CKD that becomes apparent once euthyroidism has been re-established. 43 In the light of recognition that CKD predisposes to AKI, it is not surprising that the hyperthyroid cats in this study had urine KIM-1 concentration at the high end or above that of control cats.…”

Acoustic bubbles in therapy: Recent advances with medical microbubbles, clouds, and harmonic antibubbles

“…Anastasiia Panfilova from Eindhoven University of Technology had a poster presentation on the relation between contrast-ultrasound kinetic features and microvascular density by acoustic angiography [23]. Katrien Vanderperren from Ghent University presented a poster on renal ageing in cats assessed by contrast-enhanced ultrasound [24] and a poster on the evaluation of renal perfusion using contrast-enhanced ultrasound in cats with chronic kidney disease [25]. Letizia Oddo from the University of Rome Tor Vergata showed in a poster the next generation of ultrasound platforms for theranostics [22].…”