SIMULTANEOUS TEMPORAL RESOLUTION OF CARDIAC AND RESPIRATORY MOTION INMR-IMAGING

PURPOSE: To evaluate a magnetic resonance (MR) imaging method that all ows for simultaneous resolution of both the cardiac and respiratory cy cles. MATERIALS AND METHODS: Conventional and phase-contrast cine sequ ences were modified to provide additional resolution of the respirator y cycle. Data were collected in 11 healthy volunteers during MR imagin g of the heart and portal vein. The imaging time was increased over th at of a conventional cine acquisition by a factor equal to the number of frames in the respiratory cycle. Data were compared with those from comparable sequences in which only one motion cycle was resolved. RES ULTS: In the heart, motion due to cardiac dynamics was separated from respiration-induced excursions. The extent of motion could be measured , and artifacts were minimized. Changes in flow rate as a function of both motion cycles were resolved and quantified in both the portal vei n and superior vena cava. CONCLUSION: This method allows for simultane ous resolution of cardiac and respiratory motion cycles and helps prov ide a more physiologic view of the effects of cardiac and respiratory variations.