Magnetic resonance imaging of the lentiform nuclei in dogs with portosystemic shunts

Abstract

This method of quantifying the T1-weighted magnetic resonance imaging signal intensity of the lentiform nuclei was reliable and showed that dogs with portosystemic shunts tend to have increased signal intensity. Further prospective studies are necessary to investigate the clinical significance and applications of these findings.

Cerebellar granuloprival and trans‐synaptic degeneration in a Chihuahua

“…From the neurological point of view, affected dogs tend to show prosencephalic signs with altered mental status, circling, seizures, altered behaviour in association with mild ataxia, which are completely different signs compared with our case 19. Moreover, it is reported that in dogs with PSS on T1-weighted images on MRI, there is a hyperintensity of the lentiform nucleus that was not observed in this case 20. A clear relationship between postprandial bile acids elevation and CGD has not been found.…”

Incidence and risk factors for neurological signs after attenuation of single congenital portosystemic shunts in 253 dogs

“…14 HE is commonly observed in man secondary to a variety of liver diseases, but the pathogenesis remains unclear. HE may cause chronic alterations in the central nervous system (CNS), [15][16][17][18][19][20] and there is direct evidence of astrocyte alterations in the brains of dogs with CPSS. 10,21 The CNS is believed to adapt to an abnormal metabolic environment preoperatively, and the sudden change caused by surgical attenuation favors an excitatory state.…”

MRI findings in two West Highland White Terrier dogs with hepatic encephalopathy secondary to portosystemic shunt

“…A PSS is an abnormal communication between the portal vascular system and the systemic circulation 1–4. Higher concentrations of endogenous and exogenous toxins that are normally metabolised or eliminated bypass the liver 1–3. Since metabolism or detoxification is not performed first pass by the liver, there is impaired clearance of ammonia and other toxins there and HE occurs 3.…”

“…HE is a progressive disorder with a wide spectrum of neuropsychiatric abnormalities and motor disturbances 4 5. The clinical signs associated with PSS result from HE involving a variety of neurological signs, including behavioural changes, ataxia, unresponsiveness, pacing, circling, blindness, seizures and coma2 4 and death 6…”

“…Several pathogenic mechanisms have been implicated including neurotoxicity secondary to ammonia,1–4 mercaptans,2 phenols,2 manganese,1–4 increased gamma‐aminobutyric acid neurotransmission,2 4 neural inflammation,4 natural benzodiazepine‐like compounds,4, hypertyramenia12 and oxidative and nitrosative stress (ONS) 5 13. Increased levels of ammonia within the central nervous system (CNS) generate reactive oxygen and nitrogen species leading to ONS13 and consequently to increased astrocytic volume.…”