الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The rapid evolution and increasing complexity of liver directed therapies has forced the medical community to further advance its understanding of hepatic vascular anatomy
Variant hepatic arterial anatomy not only dictates the surgical technique but may also predicts the risk of surgical hepatic arterial complications.
A wide variety of imaging strategies are used to provide comprehensive preoperative information concerning the arterial, portal venous, and hepatic venous anatomy.
Catheter angiography has long been considered the standard of reference for evaluation of the hepatic arterial anatomy. However, the morbidity and mortality associated with catheter angiography, coupled with the limitations of this procedure in demonstrating the hepatic venous anatomy, have provided impetus for the development of non invasive methods of displaying the vascular anatomy.
Modern non invasive diagnostic imaging techniques such as MDCT have replaced conventional angiography for evaluation of the hepatic vasculature anatomy.
This study included 20 patients presented to radiology department of Alexandria University Hospital with various abdominal problems for CECT abdomen assessment.
All patients will subject to the following: Clinical assessment including history taking, Laboratory study: it includes all the routing laboratory workup with stress on the level of creatine and blood urea nitrogen and CTA examination.
Dual arterial phase is used instead of the single arterial phase. Bolus tracking technique is used with the first arterial phase is starting 4 seconds after the attenuation in the descending aorta reaching 100 HU. Which takes about 10 seconds the first arterial phase scan starting from the dome of the liver to its caudal end and taking 7seconds ,7 seconds inter-scan delay then the second arterial phase starts with the same range of scan as the first one and taking 7 seconds.
The portal venous phase starting 7 seconds after the end of the second arterial phase and the scan range staring from the dome and covering all the abdomen and pelvis taking 15 seconds duration.
Delayed scans starting 5 minutes after the end of portal venous phase and covering the same range of the portal venous phase.
Our study showed that the hepatic vascular variants are seen in 12 cases mounting 60% of the total number of study cases.
The most common arterial variant was Michel’s type three and it is seen in 5 cases and counting for 25% of our study cases.
The most common origin of segment IV artery was the left hepatic vein and it is seen in 17 cases and counting for 85 % of our study cases.
The most common origin of gastro-duodenal artery in our study was from the common hepatic artery and it is seen in 13 cases and counting for 65 % of our study cases.
The most common branching pattern of the portal vein encountered in our study was the classic branching pattern and it is seen in 13 cases and counting for 65 % of our study cases.
The most common origin of segment IV portal vein branches in our study was combined sharing from the right and left main portal veins and it is seen in 14 cases and counting for 70 % of our study cases.
The late arterial phase was more beneficial than the portal venous phase in depiction of portal vein distal sub-segmental branches while portal venous phase was more beneficial in characterization of the hepatic veins.
Hepatic veins variants in our study were counting for 63 % of adequately characterized of cases with adequate hepatic venous characterization.
The most common surgically important hepatic venous variants in our study was branches of the middle hepatic vein that cross the surgical hepatectomy plane; this variant counts for 36 % of cases with adequate hepatic venous characterization.
Multi–detector row CT in a triphasic hepatic dynamic study, including a single-breath hold dual-arterial phase acquisition, was useful for the depiction of the small hepatic arterial and portal venous anatomy.
We propose that the first arterial phase should be used for CT arteriography; the second arterial phase, for CT portography; and the portal venous phase, for CT venography.