兩項最新的研究表明核磁共振組織彈性成像(MRE)，一種新的成像技術，是一種非侵襲性診斷肝臟疾病的工具。

肝臟可由于很多疾病造成其細胞破壞并發展成瘢痕組織或纖維化。MRE是MRI基礎上發展而來的，并且可以有效測量肝臟的硬度和彈性。對肝臟振動的同時，MRE可獲得機械波穿透器官后所成的像。圖像經過處理后就可得到相應組織有關硬度的信息。

健康肝臟組織是非常柔軟的，而纖維化的肝臟是比較硬的，而硬化后的肝臟像巖石一樣堅硬。

Mayo診所Richard Ehman博士解釋道。如果發現得較早，肝纖維化是可以逆轉的，但一旦發展成肝硬化，就不可逆轉了。

Ehman博士和他的研究團隊并在胃腸道醫師的幫助下，研究MRE是否可在不同肝臟疾病水平提供可信和準確的信息。這項研究涉及57名慢性肝臟疾病患者和20例健康志愿者。研究表明，MRE在診斷肝纖維化上具有靈敏性和特異性。研究還表明脂肪變性，脂肪酸和甘油三脂在肝細胞內沉積所造成，這是一種肝臟疾病普遍性病變，并不影響MRE對纖維化的檢測。

第二項Mayo研究檢測MRE是否能準確檢測門靜脈高壓、或者門靜脈高血壓所致血液從消化道流入肝臟，典型的肝硬化結果。這項研究涉及35例慢性肝硬化病人和12例健康志愿者。研究人員通過MRE檢測肝臟和脾臟的硬度發現肝臟和脾臟硬度與門靜脈高壓有顯著的相關性。

根據Ehman博士的看法，許多可導致組織改變的疾病在未來都可通過MRE來檢測。他的研究團隊正在評估使用MRE檢測乳腺癌和老年癡呆的可行性。

這些研究成果在2007年5月柏林舉行的核磁共振年會以及今年在華盛頓舉行的消化疾病會議上分別作了展示。


MRI Elastrography Provides Effective Noninvasive Liver Diagnoses 
     
Two recent studies have found that magnetic resonance elastography (MRE), a new imaging technique, is an accurate tool for noninvasive diagnosis of liver disease.
 
The liver responds to many diseases that damage its cells by developing scar tissue or fibrosis. MRE, developed at the Mayo Clinic (Rochester, MN, USA), uses a modified form of magnetic resonance imaging (MRI) to effectively measure the hardness or elasticity of the liver. By applying vibrations to the liver, MRE obtains images of the mechanical waves passing through the organ. The wave images are then processed to generate a quantitative image of tissue stiffness. 

ealthy liver tissue is very soft, while a liver with fibrosis is firmer, and a liver with cirrhosis is almost rock-hard,?stated Richard Ehman, M.D., lead Mayo Clinic researcher on the MRE project. f detected early, fibrosis of the liver can be treated, but once the disease has progressed to cirrhosis, the condition is irreversible.

Dr. Ehman and his imaging research team collaborated with Mayo Clinic gastroenterologists to study whether MRE could provide reliable and accurate diagnoses in patients with varying levels of liver disease. One study involved MRE examinations of 57 individuals with chronic liver disease and 20 healthy volunteers. The researchers confirmed that MRE accurately detects fibrosis with high sensitivity and specificity. Researchers also found that steatosis, which is deposits of fatty acids and triglycerides in liver cells and a common condition in patients with liver disease, did not interfere with detection of fibrosis with MRE. 

The second Mayo study looked at whether MRE can accurately measure portal hypertension, or high-blood pressure in the portal vein that carries blood from the digestive track to the liver, typically as a result of cirrhosis of the liver. This study involved 35 individuals with differing degrees of chronic liver disease and 12 healthy volunteers. Researchers assessed MRE examinations of liver and spleen stiffness and discovered that a highly significant correlation exists between liver and spleen stiffness in patients with portal hypertension. 

According to Dr. Ehman, many disorders cause the characteristics of tissue to change and will be likely candidates for diagnosis using MRE in the future. His research team is now evaluating the use of MRE in detecting breast cancer and Alzheimer disease. 

The findings were presented in May 2007 at the International Society for Magnetic Resonance in Medicine annual meeting in Berlin, Germany, and Digestive Disease Week 2007 in Washington, DC, USA.