الفهرس | Only 14 pages are availabe for public view |
Abstract Minimally invasive interventional therapies of primary and secondary liver lesions are increasingly being considered attractive alternatives to surgery in patients ineligible for surgery. The technical success of a surgical procedure can be validated by confirmation of tumor-free margins at pathologic examination ofthe resected specimen. Becauselocal tumor ablation, attempts to emulate the results of surgery, there is a need to use various imaging techniques to verify the adequacy and completeness of the procedure. Early identification of treatment failure is critical in patient management, since a repeat treatment cycle can be performed if liver function is maintained, before disease progression occurs. Contrast enhanced triphasic Computer tomography CT is widely accepted as the first investigation of choice of the malignant hepatic focal lesions after local ablative procedures. The new advance in CT machines with fast scanning, thinner section and higher resolution gives CT a good sensitivity and specificity for local tumoral recurrence. MRI is a powerful tool in detection of residual or recurrence after minimal invasive ablative procedures of the liver focal lesions. With the inhered high tissue contrast, using of different sequences and multiplanerimaging of the MRI. Using of contrast media that enhance the ability of MRI to detect Recent studies were done using the different physical character of the MRI contrast medias to improve the evaluation of the ablative lesions such as the evaluation of the ablative margin (AM) using a liver specific contrast media a feurocarbotranclearance. Macromolecular contrast media (necrosis avid contrast media) as they express less capillary permeability than conventional MRI contrast media which enables better differentiation between marginaltumoral recurrence and post ablative perilesional hyperemia. The use of diffusion weighted images (DWI) is not limited to characterization of the hepatic focal lesions. It also extended to evaluation of the ablative lesions as the residual/recurrence tumor shows different diffusion signal and ADC value than surrounding ablative lesion and surrounding hyperemia, it is feasible to use DWI in evaluation of suspicious areas. Unlike conventional diagnostic modalities, such as CT scans and ultrasound, which require anatomic alterations for detection of malignancy, FDG-PET can detect early tumor growth as it based on increased glucose uptake and metabolism of malignant cells. With the advantage of fusion of morphologic and functional images, as in PET-CT provided a useful view of the spatial relationship of lesion structure and functional significance. |