MR-IMAGING OF ROTATOR CUFF TENDON TEARS - COMPARISON OF T2-ASTERISK-WEIGHTED GRADIENT-ECHO AND CONVENTIONAL DUAL-ECHO SEQUENCES

OBJECTIVE. Although MR imaging evaluation of the rotator cuff is usual ly done with proton density- and T2-weighted spin-echo techniques, int erest also exists in T2-weighted gradient-recalled echo techniques, T he shorter scan times of T2-weighted sequences can be used to increas e the number of signal averages and thus improve the signal-to-noise r atio. Our purpose in this study was to compare the sensitivity and spe cificity of oblique coronal T2-weighted MR image interpretations with conventional dual-echo T2-weighted MR image interpretations when diag nosing rotator cuff tears. SUBJECTS AND METHODS. Forty-seven consecuti ve patients who underwent both MR imaging and shoulder arthroscopy wer e included in this study. The MR examination included both a 7 min 20 sec acquisition time proton density- and T2-weighted oblique coronal s equence and a: min 5 sec T2-weighted oblique coronal sequence. The ob lique coronal dual-echo T2-weighted images were evaluated by two of th e authors independently, who were unaware of the arthroscopic findings . Each of the two observers graded each cuff as being intact, having a partial-thickness tear, or having a full-thickness tear. After a 3-we ek interval, each of the two observers then interpreted the T2-weight ed oblique coronal MR images in the same manner, Sensitivity and speci ficity for the two sets of interpretations were calculated in terms of the ability of the observers to use the two sequences to distinguish an intact cuff from a rotator cuff tear and to distinguish a partial-t hickness cuff tear from an intact cuff or full-thickness rear, The res ults were then compared using Student's t test calculations. RESULTS. For distinguishing an intact cuff from a tom cuff, the sensitivity of the observers' interpretations was lower for the T2-weighted images t han for the conventional dual-echo T2-weighted images. The specificity also decreased with interpretation of the T2-weighted images for one observer and was unchanged for the second observer. For distinguishin g a partial-thickness cuff tear from a non-partial-thickness cuff tear (intact or full-thickness tear), the sensitivity and specificity of b oth observers decreased with interpretations of dr T2-weighted images when compared with the conventional dual-echo T2-weighted images. The results did not reach statistical significance. CONCLUSION. In this s mall study evaluating the ability of observers to diagnose rotator cuf f tears on oblique coronal MR images only, interpretations of T2-weig hted images tended Eo be less sensitive and specific than interpretati ons of standard dual-echo T2-weighted images.