Pathophysiology
The vascular amyloid pathology characteristic of CAA can be classified as either Type 1 or Type 2, the latter type being the more common. Type 1 CAA pathology entails detectable amyloid deposits within cortical capillaries as well as within the leptomeningeal and cortical arteries and arterioles. In type 2 CAA pathology, amyloid deposits are present in leptomeningeal and cortical arteries and arterioles, but not in capillaries. Deposits in veins or venules are possible in either type but are far less prevalent. Diagnosis
CAA can only be definitively diagnosed by a post-mortem autopsy. Biopsies can play a role in diagnosing probable cases. When no tissue is available for biopsy, the Boston Criteria are used to determine probable CAA cases from MRI or CT scan data. The Boston Criteria require evidence of multiple lobar or cortical hemorrhages to label a patient as probably having CAA. Susceptibility weighted imaging has been proposed as a tool for identifying CAA-related microhemorrhages. Imaging
Cerebral amyloid angiopathy can be presented with lobar intracerebral hemorrhage or microbleeds in the brain. The bleeding usually occurs on the surfaces of the brain in contrast with intracranial haemorrhage due to high blood pressure which occurs in deep locations of the brain such as basal ganglia and pons. In lobar intracerebral bleed, computed tomography (CT) scan would show hyperdense haemorrhage area and hypodense odema around the haemorrhagic site.MRI sequence of gradient echo and susceptibility weighted imaging (SWI) are useful in detecting microbleeds and deposition of iron on the brain cortex (cortical superficial siderosis).
Pyelectasis is a dilation of the renal pelvis. It is a relatively common ultrasound finding in fetuses and is three times more common in male fetuses. In most cases pyelectasis resolves normally, having no ill effects on the baby. The significance of pyelectasis in fetuses is not clear. It was thought to be a marker for obstruction, but in most cases it resolves spontaneously. In some studies it has been shown to appear and disappear several times throughout the course of pregnancy. There is some discussion about what degree of pyelectasis is considered severe enough to warrant further investigation and most authorities use 6mm as the cut-off point. Pyelectasis is considered to be a "soft marker” for Down syndrome. This, along with other factors such as age and abnormal maternal serum screening (exa, Integrated or Quad screen), may be grounds for a prenatal diagnostic test such as an amniocentesis to rule out Down syndrome. Babies with unresolved pyelectasis may experience urological problems requiring surgery. Etymology and pronunciation
The word pyelectasis () is derived from the prefix pyelo-, meaning "[renal] pelvis", and ectasis, meaning "dilation or distension". External links
OBfocus.com
The Fetus.net
The Harvey Institute for Human Genetics
Radiopedia article