الفهرس 
ANATOMY OF LIVEROnly 14 pages are availabe for public view
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Abstract
Orthotopic liver transplantation (OLT) is cur-rently the treatment of choice for patients with severe acute or chronic liver failure for which no other thera-py is available.
Over the past several decades, advances in sur-gical techniques, organ preservation, immunosuppres-sive therapy, and early detection of postoperative complications have increased survival rates after liver transplantation.
However, there are still significant complica-tions, particularly those of vascular origin, which can lead to graft failure and require reoperation unless prompt treatment is instituted. Vascular complication include hepatic artery stenosis (HAS), hepatic artery thrombosis (HAT), hepatic artery pseudoanyreausm, portal vein thrombosis or stenosis, IVC stenosis or thrombosis and hepatic veins thrombosis & stenosis.
Vascular complications develop in 8% of LTX cases and should be considered in patients with evi-dence of graft failure, biliary strictures and leaks, ga-strointestinal bleeding or septicemia. Hepatic artery stenosis or thrombosis is the most common and significant vascular complication and accounts for approximately 60% of LTX vascular complications.
Early and accurate diagnosis of vascular compli-cations is crucial for increasing the survival rate of the graft in living related liver transplantation because most stenoses or thromboses are treatable with interventional procedures and since the clinical presentation of posttransplantation vascular complications is frequently nonspecific and varies widely, imaging studies are critical for early diagnosis.
The use of multidetector CT scanners has led to decreased scanning time and improved overall image quality with thin-section acquisitions.
The thinner images with MDCT provides some benefits, such as reduced volume-averaging artifacts, thereby improving diagnosis of hepatic vascular pa-thologies. Also multiplanar imaging and CT angiogra-phy are much better.
A MDCT angiographic study easily generates over a thousand axial images. Post processing of the dataset offers a variety of advanced three-dimensional models of the hepatic vessels using multi-planar re-construction (MPR), maximum intensity projection (MIP), and volume rendering (VR) reconstructions.
Although Doppler sonography is considered a primary screening method for detecting postoperative vascular complications, extensive bowel gas and he-matomas can sometimes obscure accurate results on sonographic studies. As an alternative noninvasive technique for evaluating the hepatic vasculature, MDCT can provide excellent visualization of filling defects or focal narrowing of hepatic vessels.
MDCT angiography is the best option for con-firmation the ultrasonographic suspicion of early and late vascular complications (HAT, main portal vein or inferior vena cava (IVC) stenosis or thrombosis).
The high accuracy, noninvasiveness, fast inter-pretation with reconstructed images and low cost (less than one-third the cost of conventional angiography) are advantages of MDCTA over DSA.
It is suggested that if any vascular complication is suspected with Doppler ultrasound, MDCTA must be performed for diagnosis, and after that, only if se-vere/moderate stenosis is detected, the patients must undergo DSA for PTA and/or stent placement therapy due to the high accuracy of the MDCTA examination.
3DCTA provides sufficient information not only on patency or stenosis of smaller vessels but also on other abnormalities in the liver parenchyma, biliary, and extra-hepatic sites, which forms the major deci-sion for the treatment of the detected vascular compli-cation.
In conclusion, Multi-detector CT is a safe, non-invasive, accurate, and reliable method that can be used to show patency, stenosis, or thrombosis of the hepatic vessels in liver transplant patients and so with the current role of CT for the detection of nonvascular transplant complications, multi-detector CT angiography with 3D volume rendering is an exciting modality that may be the only imaging test required in the evaluation of patients after liver transplantation.