MR CHOLANGIOGRAPHY

MR Imaging of the Gallbladder and Biliary System

MR imaging is an established technique for the diagnosis of a spectrum of biliary and gallbladder pathologies and continues to improve with the advent of technologic advances, including new contrast agents and new sequences that are capable of improving upon the contrast resolution and signal-to-noise that are afforded by conventional MR imaging. These improvements already have shown promise for the increasing role of MRC as the initial modality in assessing living liver donors and evaluating post-operative hepato-biliary complications. Improved spatial resolution and the added functional or physiologic information afforded by MR imaging promise ever expanding clinical applicability and usefulness.

Evaluation of Living Liver Transplant Donors: Method for Precise Anatomic Definition by Using a Dedicated Contrast-enhanced MR Imaging Protocol

Liver transplantation from a living donor involves removal of part of the donor liver in a fashion that does not endanger its vascular supply or metabolic function. The radiologist plays an important role in evaluation of the living donor to define the conditions under which graft donation is contraindicated and to identify anatomic variations that may alter the surgical approach. In the past, diagnostic work-up of the donor involved costly and invasive tests. Currently, dynamic contrast material-enhanced computed tomography and magnetic resonance (MR) imaging are the imaging tests performed, each of which has advantages and limitations. MR imaging performed with liver-specific and extravascular contrast agents may be used as a single imaging test for comprehensive noninvasive evaluation of living liver transplant donors. MR imaging provides valuable information about variations in the vascular and biliary anatomy and allows evaluation of the hepatic parenchyma for diffuse or focal abnormalities.

MR imaging in abdominal emergencies

The use of MR imaging in the emergency setting is evolving. Clear indications include situations in need of contrast media when iodinated contrast cannot be administered or to facilitate assessments in pregnant patients and children when exposure to ionizing radiation is considered unacceptable. The availability of rapid, motion-immune sequences now makes MR imaging a feasible study in less cooperative patients extending the range of patients for whom a diagnostic study can be achieved. Capitalizing on the unique benefits of MR imaging there is optimism that MR imaging can eliminate test redundancy and impact patient care in a cost-effective manner. Further investigations are needed to identify the diagnostic algorithms for which this favorable use holds true.