الفهرس 
Gross AnatomyOnly 14 pages are availabe for public view
Abstract
Benign lesions of the liver are common and are frequently discovered during investigations for unrelated intra-abdominal conditions.
Most are asymptomatic, but chronic non-specific symptoms are occasionally encountered; acute presentations are rare, but may require immediate attention. In general, liver biochemistry is normal and does not provide definite diagnostic clues, but prompts towards benign disease.
MR imaging plays an important role in the workup of the otherwise indeterminate lesion, and often can be definitive in characterization.
It is important to consider the characteristic MR imaging features of benign focal hepatic lesions so as to avoid biopsy, surgery, and extensive workups. Advances in MR imaging technology and in some cases, a better understanding of the lesion itself, have allowed for improved lesion diagnosis.
MRI having many sequences, markedly helps in the detection of small lesions and in reaching the diagnosis easily even without contrast injection or the need for biopsy as in cysts and hemangiomas.MRI provides multiplanar information in great range of liver lesions & makes successful diagnosis when other modalities fail, it provides details of vessels & bile ducts giving the best way to diagnose, stage hepatic tumors & assess their blood supply. Nowadays dynamic contrast-enhanced 3D GRE MR imaging is excellent for the evaluation of various hepatic tumors.
For hepatic focal lesions detection and characterization, conventional MRI relies on T1-weighted, T2-weighted, dynamic gadolinium-enhanced T1-weighted imaging and diffusion weighted images.
Dynamic contrast enhanced MRI provides the most information about lesion characterization in general, & it is most helpful in distinguishing liver lesions types & in assessing their response to therapy.
In general, dynamic MRI has advantages over other imaging modalities in diagnosis of hepatic lesions because it is more accurate, no exposure to radiation & no use of nephrotoxic contrast agents, so it seems reasonable to predict that the use of dynamic contrast enhanced images of the liver will become far more common, & may replace routine multiphasic imaging approaches like CT.DW MRI in the liver is a relative new and increasingly used imaging technique. The ADC maps can also provide quantitative measurements of tissue water diffusivity, which can be used not only for disease assessment, but also for the evaluation of disease response to treatment.
DWI has been reported to be useful for the early detection of focal liver lesions. Moreover, it offers the possibility to obtain criteria for lesion characterization without the need for contrast agent administration by quantifying diffusion effects via ADC measurements, with better results compared with those of conventional MRI.