To evaluate the effectiveness of the iterative decomposition of water and fat with echo asymmetric and least-squares estimation (IDEAL) MRI to quantify tumour infiltration into the lumbar vertebrae in myeloma patients without visible focal lesions.

PURPOSE:Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) is a recently developed liver-specific contrast agent for magnetic resonance (MR) imaging that is excreted equally via the kidneys and the biliary system. To our knowledge, its effects on T(2)-weighted MR cholangiopancreatography (MRCP) images have not been explored. Acquisition of the hepatobiliary phase is recommended 20 min after administration of Gd-EOB-DTPA. Examination time cannot be extended if the contrast does not take effect on T(2)-weighted MRCP within 20 min after administration. We attempted to assess the change in signal of T(2)-weighted MRCP by excretion of Gd-EOB-DTPA.METHODS:Between March and July 2008, 40 patients (15 women, 25 men; mean age 70.8 years) were examined with abdominal MR imaging. T(2)-weighted MRCP was performed before and 10 and 20 min after administration of Gd-EOB-DTPA. We analyzed signal intensity of the bile duct, gallbladder, cystic duct, and pancreatic duct on MRCP for changes in intensity.RESULTS:T(2)-weighted MRCP 20 min after contrast administration showed loss of signal of the bile duct (intrahepatic bile duct in all cases, upper extrahepatic duct in 36 [90%], middle extrahepatic duct in 33 [85%], and lower extrahepatic duct in 26 [67%]), the gallbladder in 23 cases (72%), and the cystic duct in 25 (64%). This signal change increased with time. We observed no change in signal of the pancreatic duct.CONCLUSION:T(2)-weighted MRCP sequences should not be obtained after administration of Gd-EOB-DTPA because this contrast agent decreases signal intensity of the biliary structure on these images.

We report a case of MELAS in which lesions were detected by perfusion-weighted MR imaging. Perfusion-weighted MRI using contrast media (PWI) and FAIR (flow-sensitive alternating inversion recovery), an arterial spin labeling method, clearly showed these lesions as hyperperfused areas. One of these lesions, diminished after steroid therapy, could also be detected by FAIR.