RELATIONSHIP BETWEEN PULSE SEQUENCES AND SIGNAL INTENSITY OF JOINT FLUID IN THE GRADIENT-ECHO MR-IMAGING

To depict the labrum and meniscus in terms of contrast to joint fluid by increasing its signal intensity, we examined in vitro and in a huma n subject the good imaging conditions of gradient-echo magnet resonanc e by using a 1.0 Tesla superconducting imager (Shimadzu). In our in vi tro study, 3 types of joint fluid and physiological saline were imaged together with PVA gel(as the substitute for surrounding soft tissue), by using either the STAGE, SSFP, or STERF method, and with several TR 's (repetition time); and mean signal intensity was obtained. In order to confirm the findings of the in vitro study, a human study was cond ucted: physiological saline was injected into a shoulder joint, and ax ial planes were depicted under the conditions equivalent to those of t he in vitro study, With the STERF method, signal intensity of the flui d was high at any flip angle, but PVS gel and the surrounding soft tis sues such as muscles were rarely depicted. With the STAGE and SSFP met hods, depiction of the fluid, PVA gel, and the surrounding soft tissue s were possible by setting an appropriate flip angle for TR: With the STAGE method (a spoiled gradient echo sequence), good imaging was poss ible by selecting small flip angle, regardless TR. Therefore, because of easiness in selecting conditions, the STAGE method is considered to be the best for diagnostic scanning. (C) 1997 Elsevier Science Inc.