USEFULNESS OF TURBO SPIN-ECHO MR-IMAGING IN THE EVALUATION OF MENISCAL TEARS - COMPARISON WITH A CONVENTIONAL SPIN-ECHO SEQUENCE

OBJECTIVE. Fast (turbo) spin-echo imaging techniques have replaced con ventional spin-echo protocols in a large proportion of MR applications , with the principle advantage of decreased imaging time. The choice o f echo train length is a key determinant of time savings realized, but the echo train length can also adversely affect image quality if too many echoes are incorporated into an image. Several recent studies hav e shown conflicting results regarding the usefulness of turbo spin-ech o imaging in the evaluation of meniscal tears. We compare a turbo Spin -echo sequence that has an echo train length of five with a convention al spin-echo sequence for evaluating meniscal tears. SUBJECTS AND METH ODS. Forty knees in 39 consecutive patients referred for MR study of t he knee were imaged using both conventional spin-echo and turbo spin-e cho sequences. The turbo spin-echo sequence provided both proton densi ty-weighted and T2-weighted images (dual echo technique) with an effec tive echo-train length of five. Nineteen knees (38 menisci) were studi ed arthroscopically. The arthroscopic findings were considered the ref erence standard. Spin-echo and turbo spin-echo images were reviewed re trospectively, and results were compared statistically. RESULTS. Of th e 80 menisci evaluated with MR imaging, spin-echo and turbo spin-echo images provided concordant results in 95% of cases, with no Statistica lly significant difference found between the two techniques (p < .05). Seventeen tears were found at arthroscopy in 38 studied. Spin-echo an d turbo spin-echo imaging had identical specificities menisci (90%) an d similar sensitivities (88% and 82%, respectively). CONCLUSION. This study shows that proton density-weighted sequences with an echo train length of five preserve sufficient high-spatial-frequency information to provide performance similar to that of conventional spin-echo seque nces. Our data support the conclusion that fast spin-echo imaging with short echo train length is a reasonable substitute for conventional s pin-echo imaging in the evaluation of the knee.