الفهرس 
MRI FINDINGS IN
Mechanism of ActionOnly 14 pages are availabe for public view
 |  | from | 85 |  |  |
| | | from | 85 | | |
Abstract
Cirrhotic livers are characterized by advanced fibrosis and
formation of hepatocellular nodules which are classified
histologically as either regenerative nodules, dysplastic nodules,
or neoplastic lesions. However, their accurate characterization
may be difficult even at histopathological analysis. Differential
diagnosis may be facilitated by comparing the clinical and
pathological findings with radiological imaging features.
MR imaging is more useful than computed tomography
and US in diagnosing the premalignant cirrhotic nodules from
the malignant ones as it is the main issue for early detection and
management of HCC. MRI provides better soft-tissue contrast
and identification of different tissue properties by their signal
appearance on different MR phases especially with the
introduction of faster sequences while in MSCT we judge only
on dynamic post contrast study. Moreover, a wide variety of
contrast agents are currently available for use in MR imaging
which provides greater sensitivity to these contrast media.
For hepatic focal lesions detection and characterization,
conventional MRI relies on T1-weighted, T2-weighted and
dynamic gadolinium-enhanced T1-weighted imaging.
Additionally, DW MRI in the liver is a relatively new and
increasingly used imaging technique. It has the advantage that
it can be obtained during a single breath-hold, there is no need
to use contrast media, and it provides unique information that reflects tissue cellularity and organization. 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.
This MR study enabled us to visualize the cirrhotic liver
nodules based on; their signal intensity pattern on different MR
phases, good tissue characterization for intracellular fat & iron
content inside the nodules by the dual in-phase and out-phase
images, and their enhancement pattern in dynamic post contrast
study as well as their feature in DWIs. It also enabled us to
detect any vascular invasion in malignant neoplastic hepatic
lesions for proper staging assessment.
MRI is a safe and well tolerated technique that is easily
performed and is sensitive for early detection of malignant
neoplastic hepatic lesions, and for differentiation between the
premalignant and the malignant lesions. This technique is
complementary to other imaging modalities and laboratory
studies for full assessment of the hepatocellular nodules in
cirrhotic livers.
Finally we concluded that; conventional MRI sequences
combined with dynamic MRI and DWI provide further more
accurate diagnoses for hepatic focal lesions so, we could be
able to reach the definite diagnosis for these hepatic focal
lesions and so stating management as early as possible which
reflect on increasing the prognostic criteria for hepatic focal
lesions.