Echocardiography is also used if there is a suspicion of pulmonary hypertension or high-output cardiac failure due to large liver lesions, sometimes followed by cardiac catheterization to measure the pressures inside the various chambers of the heart. Liver AVMs may be suspected because of abnormal liver function tests in the blood, because the symptoms of heart failure develop, or because of jaundice or other symptoms of liver dysfunction. The most reliable initial screening test is Doppler ultrasonography of the liver; this has a very high sensitivity for identifying vascular lesions in the liver. If necessary, contrast-enhanced CT may be used to further characterize AVMs. It is extremely common to find incidental nodules on liver scans, most commonly due to focal nodular hyperplasia (FNH), as these are a hundredfold times more common in HHT compared to the general population. FNH is regarded as harmless. Generally, tumor markers and additional imaging modalities are used to differentiate between FNH and malignant tumors of the liver. Liver biopsy is discouraged in people with HHT as the risk of hemorrhage from liver AVMs may be significant. Liver scans may be useful if someone is suspected of HHT, but does not meet the criteria (see below) unless liver lesions can be demonstrated.Brain AVMs may be detected on computed tomography angiography (CTA or CT angio) or magnetic resonance angiography (MRA); CTA is better in showing the vessels themselves, and MRA provides more detail about the relationship between an AVM and surrounding brain tissue. In general, MRI is recommended.
The condition is named after surgeon Norman Barrett (1903–1979) even though the condition was originally described by Philip Rowland Allison in 1946. Signs and symptoms
The change from normal to premalignant cells indicate Barretts esophagus does not cause any particular symptoms. Barretts esophagus, however, is associated with these symptoms:

frequent and longstanding heartburn
trouble swallowing (dysphagia)
vomiting blood (hematemesis)
pain under the sternum where the esophagus meets the stomach
pain when swallowing (odynophagia), which can lead to unintentional weight lossThe risk of developing Barretts esophagus is increased by central obesity (vs. peripheral obesity). The exact mechanism is unclear. The difference in distribution of fat among men (more central) and women (more peripheral) may explain the increased risk in males. Pathophysiology
Barretts esophagus occurs due to chronic inflammation. The principal cause of chronic inflammation is gastroesophageal reflux disease, GERD (UK: GORD). In this disease, acidic stomach, bile, and small intestine and pancreatic contents cause damage to the cells of the lower esophagus. In turn, this provokes an advantage for cells more resistant to these noxious stimuli in particular HOXA13-expressing stem cells that are characterised by distal (intestinal) characteristics and outcompete the normal squamous cells.This mechanism also explains the selection of HER2/neu (also called ERBB2) and the overexpressing (lineage-addicted) cancer cells during the process of carcinogenesis, and the efficacy of targeted therapy against the Her-2 receptor with trastuzumab (Herceptin) in the treatment of adenocarcinomas at the gastroesophageal junction. Researchers are unable to predict who with heartburn will develop Barretts esophagus.