Hyperthyroidism in cats, part I : anatomy, physiology, pathophysiology, diagnosis and imaging

In the first part of this review article, thyroid anatomy, physiology and pathophysiology are reviewed to continue more specifically on hyperthyroidism, the most common thyroid disorder in cats. The diagnostic work-up of this disorder is discussed with emphasis on thyroid gland imaging. Scintigraphy is most commonly used and best suited to assess thyroid function, which will be discussed extensively in the second part of this review article. All other available imaging modalities do not offer a functional assessment and are therefore of limited use in the diagnosis and evaluation of hyperthyroidism

Hyperthyroidism in cats, part II : scintigraphic diagnosis and radioiodine treatment

In the second part of this review article, the diagnostic aspects of thyroid scintigraphy are discussed, with major emphasis on hyperthyroidism, followed by an overview of radioiodine treatment

Contrast-enhanced ultrasound examination for the assessment of renal perfusion in cats with chronic kidney disease

Background: Contrast-enhanced ultrasound examination (CEUS) is a functional imaging technique allowing noninvasive assessment of tissue perfusion. Studies in humans show that the technique holds great potential to be used in the diagnosis of chronic kidney disease (CKD). However, data in veterinary medicine are currently lacking. Objectives: To evaluate renal perfusion using CEUS in cats with CKD. Animals: Fourteen client-owned cats with CKD and 43 healthy control cats. Methods: Prospective case-controlled clinical trial using CEUS to evaluate renal perfusion in cats with CKD compared to healthy control cats. Time-intensity curves were created, and perfusion parameters were calculated using off-line software. A linear mixed model was used to examine differences between perfusion parameters of cats with CKD and healthy cats. Results: In cats with CKD, longer time to peak and shorter mean transit times were observed for the renal cortex. In contrast, a shorter time to peak and rise time were seen for the renal medulla. The findings for the renal cortex indicate decreased blood velocity and shorter total duration of enhancement, likely caused by increased vascular resistance in CKD. Increased blood velocity in the renal medulla has not been described before and may be because of a different response to regulatory factors in cortex and medulla. Conclusions and Clinical Importance: Contrast-enhanced ultrasound examination was capable of detecting perfusion changes in cats with CKD. Further research is warranted to assess the diagnostic capabilities of CEUS in early stage of the disease process

What's a brain: neuroanatomy and neurochemistry of anxiety disorders in dogs

This review deals with the neurocircuitry of fear and anxiety disorders, with the focus on neuroanatomy and neurochemistry. This knowledge is required to correctly diagnose and treat dogs with anxiety-related behavioral disorders. Research to date has shown the involvement of the frontal cortex, the amygdala, the thalamus and the hippocampus as core regions in regulating fear. Imbalances (hyper- or hypoactivation) in this fear circuitry can trigger inappropriate fear responses, i.e. anxiety disorders. Serotonin, dopamine and norepinephrine are the main neurotransmitters of emotion in the brain, but gamma-aminobutyric acid (GABA), glutamate, and the hypothalamic-pituitary-adrenal (HPA) axis producing glucocorticoids are also important in the neurochemistry of anxiety

Portal vein hypoplasia in dogs

Portal vein hypoplasia (PVH) is a congenital disorder, in which microscopic intrahepatic shunts are present, causing blood to bypass the liver sinusoids. As the clinical presentation and the laboratory findings are similar to those in dogs with an extrahepatic portosystemic shunt (EHPSS), differentiation between both disorders is based on the confirmation of a macroscopic shunt by diagnostic imaging techniques. This review highlights the major aspects of PVH, including the differentiation from EHPSSs, and the challenges to diagnose both disorders in dogs with concurrent PVH and EHPSS

Functional brain imaging : a brief overview of imaging techniques and their use in human and canine anxiety research

When used in combination with specific radioactive markers, functional imaging modalities such as Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) enable the visualization of several neurotransmitter receptors and transporters, as well as of the perfusion and metabolism of the brain. This paper gives an overview of the functional imaging techniques, as well as of the studies that have been performed on humans and canines with anxiety disorders. Thus far, most of the research in this field has been focused on brain perfusion and the serotonergic and dopaminergic neurotransmitters, and less on gamma-aminobutyric acid (GABA), glutamate, norepinephrine and the hypothalamic-pituitary-adrenal (HPA) axis

Nuclear medicine: investigation of renal function in small animal medicine

Kidney function investigations in veterinary medicine are traditionally based on blood analysis (blood urea nitrogen (BUN) and serum creatinine concentration) and / or urinalysis (urine specific gravity, protein-to-creatinine ratio or fractional excretion). Morphologic information is usually obtained by abdominal radiography or ultrasonography. However, when more specific information on the functionality of the kidneys is needed, nuclear medicine offers various tracers that specifically represent glomerular filtration rate, effective renal plasma flow or functional renal mass, sometimes combining functional and morphologic data. These procedures can be based on blood sampling techniques (non-imaging methods), or data can be obtained using a gamma-camera (imaging methods). The most commonly used radionuclides for the examination of kidney function in small animal medicine are discussed in this review

Evaluation of feline renal perfusion with contrast-enhanced ultrasonography and scintigraphy

Contrast-enhanced ultrasound (CEUS) is an emerging technique to evaluate tissue perfusion. Promising results have been obtained in the evaluation of renal perfusion in health and disease, both in human and veterinary medicine. Renal scintigraphy using Tc-99m-Mercaptoacetyltriglycine (MAG(3)) is another non-invasive technique that can be used to evaluate renal perfusion. However, no data are available on the ability of CEUS or Tc-99m-MAG(3) scintigraphy to detect small changes in renal perfusion in cats. Therefore, both techniques were applied in a normal feline population to evaluate detection possibilities of perfusion changes by angiotensin II (AT II). Contrast-enhanced ultrasound using a bolus injection of commercially available contrast agent and renal scintigraphy using Tc-99m-MAG(3) were performed in 11 healthy cats after infusion of 0,9% NaCl (control) and AT II. Angiotensin II induced changes were noticed on several CEUS parameters. Mean peak enhancement, wash-in perfusion index and wash-out rate for the entire kidney decreased significantly after AT II infusion. Moreover, a tendency towards a lower wash-in area-under-the curve was present. Renal scintigraphy could not detect perfusion changes induced by AT II. This study shows that CEUS is able to detect changes in feline renal perfusion induced by AT II infusion