For the development and evaluation of cardiac magnetic resonance (MR) imagi
ng sequences and methodologies, the availability of a periodically moving p
hantom to model respiratory and cardiac motion would be of substantial bene
fit Given the specific physical boundary conditions in an MR environment, t
he choice of materials and power source of such phantoms is heavily restric
ted. Sophisticated commercial solutions are available; however they are oft
en relatively costly and user-specific modifications may not easily be impl
emented. We therefore sought to construct a low-cost MR-compatible motion p
hantom that could be easily reproduced and had design flexibility. A commer
cially available K'NEX construction set (Hyper Space Training Tower, K'NEX
Industries, Inc., Hatfield, PA) was used to construct a periodically moving
phantom head The phantom head performs a translation with a superimposed r
otation, driven by a motor over a 2-m rigid rod. To synchronize the MR data
acquisition with phantom motion (without introducing radiofrequency-relate
d image artifacts), a fiberoptic control unit generates periodic trigger pu
lses synchronized to the phantom motion. Total material costs of the phanto
m are US$ < 200.00, and a total of 80 man-hours were required to design and
construct the original phantom. With schematics of the present solution, t
he phantom reproduction may be achieved in approximately 15 man-hours. The
presented MR-compatible periodically moving phantom can easily be reproduce
d, and user-specific modifications may be implemented Such art approach all
ows a detailed investigation of motion-related phenomena in MR images.