Fat-Suppressed Dynamic and Delayed Gadolinium-Enhanced Volumetric Interpolated Breath-hold Magnetic Resonance Imaging of Cholangiocarcinoma John R. Leyendecker, MD, Mandip Gakhal, Khaled M. Elsayes, MD, Ronan McDermott, Vamsidhar R. Narra, and Jeffrey J. Brown Objective: To determine the enhancement phase providing the highest contrast-to-noise ratio (CNR) between cholangiocarcinoma and liver or portal vein on dynamic and delayed gadolinium- enhanced magnetic resonance imaging (MRI). Subjects and Methods: Precontrast, 3-phase dynamic postcontrast, and delayed postcontrast MRI of the liver was performed in 25 patients with cholangiocarcinoma and correlated with surgical findings, pathology, and other imaging studies. Contrast-to-noise ratios for tumor relative to adjacent liver and portal vein were calculated from signal intensities determined from regions of interest obtained for each phase of enhancement. A subjective assessment of the signal intensity of the periportal tissues relative to the portal vein was made for each set of delayed images. Results: A mass was visible in 24 of 25 patients. Tumor masses were hypointense in 92%, 67%, 75%, and 21%; isointense in 8%, 8%, 17%, and 12%; and hyperintense in 0%, 25%, 8%, and 67% of patients relative to liver on precontrast, arterial, portal venous, and delayed images, respectively. No single phase of gadolinium enhancement demonstrated consistently superior tumor-versus- liver CNR. Delayed imaging demonstrated the highest tumor- versus-liver CNR in 25% of patients and the lowest in 33%. The portal venous phase demonstrated the highest tumor-versusYportal vein CNR in 75% of patients. Delayed postcontrast images demonstrated the lowest tumor-versusYportal vein CNR in 38% of patients. Periportal tissues were isointense to portal vein in all but 1 patient on delayed images. Conclusion: No single phase of dynamic and delayed gadolinium- enhanced MRI demonstrates superior CNR between cholangiocar- cinoma and normally enhancing liver, although the portal phase provides the best CNR between tumor and portal vein in most cases. Although delayed enhancement is typical of cholangiocarcinoma, delayed imaging does not necessarily offer superior contrast between tumor and liver parenchyma compared with other phases of enhancement. Differentiation between tumor and portal vein and periportal tissues may be difficult on delayed images. Key Words: magnetic resonance imaging, cholangiocarcinoma (J Comput Assist Tomogr 2008;32:178Y184) C holangiocarcinoma is a malignant tumor of bile duct origin that may arise from the intrahepatic or extrahepatic biliary tree. Although treatment results with medical therapy have been disappointing, improvements in survival have been associated with surgical resection of cholangiocarcinoma. 1Y6 Successful surgical management depends on early tumor detection and accurate presurgical imaging evaluation to determine the extent of disease and eligibility for resection. Effective imaging requires that the tumor be differentiated from the surrounding liver, portal vessels, and periportal tissues to ensure tumor-free resection margins. Imaging of patients with known or suspected cholangio- carcinoma has been traditionally accomplished with some combination of percutaneous or endoscopic cholangiography, sonography, and contrast-enhanced computed tomography (CT). 7Y14 However, magnetic resonance imaging (MRI) may offer some advantage for the diagnosis and staging of cholan- giocarcinoma by combining dynamic parenchymal imaging with noninvasive magnetic resonance cholangiography. Dynamic gadolinium-enhanced fat-suppressed volu- metric breath-hold MRI is gaining popularity for imaging the liver for many indications. 15 This sequence allows fat- suppressed gadolinium-enhanced images of the entire liver to be obtained with high temporal and spatial resolution during a single breath-hold. To our knowledge, no prior study has quantitatively evaluated the enhancement characteristics of cholangiocarcinoma relative to the liver, portal vein, and periportal tissues with both dynamic and delayed postcontrast fat-suppressed volumetric interpolated MRI. Therefore, we performed this study to evaluate the relative merits of each phase of gadolinium enhancement during dynamic and delayed volumetric imaging using contrast-to-noise ratio (CNR) as an objective measure of tumor conspicuity. ORIGINAL ARTICLE 178 J Comput Assist Tomogr & Volume 32, Number 2, March/April 2008 From the Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, MO. John R. Leyendecker, MD currently at Division of Radiologic Sciences, Wake Forest University School of Medicine, Winston-Salem, NC. Mandip Gakhal currently at Department of Radiology, Christiana Hospital, Newark, DE. Khaled M. Elsayes, MD currently at Department of Diagnostic Radiology, University of Michigan Health Center, Ann Arbor, MI. Ronan McDermott currently at Department of Diagnostic Imaging, St James’s Hospital, Dublin, Ireland. Received for publication December 26, 2006; accepted March 24, 2007. Reprints: John R. Leyendecker, MD, Medical Center Blvd., Winston-Salem, NC 27157 (e-mail: jleyende@wfubmc.edu). Copyright * 2008 by Lippincott Williams & Wilkins Copyright @ 2008 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.