FAST SPIN-ECHO MR-IMAGES OF THE PELVIS OBTAINED WITH A PHASED-ARRAY COIL - VALUE IN LOCALIZING AND STAGING PROSTATIC-CARCINOMA

OBJECTIVE. The fast spin-echo pulse sequence allows T2-weighted MR ima ges to be acquired more rapidly than is possible with conventional spi n-echo sequences, and phased-array coils can provide a higher signal-t o-noise ratio than is possible with the body coil. The combination of these methods permits higher resolution images to be obtained with mor e signal averages despite shorter imaging times. In this study, initia l technical comparisons designed to confirm the advantage of combining fast spin-echo pulse sequences with a pelvic phased-array multicoil w ere followed by an assessment of the value of these methods for the lo calization and staging of prostatic carcinoma. SUBJECTS AND METHODS. S eventy-one men with known (60) or suspected (11) prostatic carcinoma w ere imaged with T2-weighted fast spin-echo pulse sequences in the axia l and coronal planes with a phased array of four surface coils (multic oil) for signal reception. Four of these men also were imaged with fas t spin-echo sequences and the body coil, and six of these men also wer e imaged with T2-weighted conventional spin echo 'sequences and the mu lticoil; image qualities achieved with these techniques were compared. The use of IV glucagon (42 of 71 studies) before fast spin-echo seque nces was correlated with the subsequent presence or absence of perista ltic artifacts on MR images. MR images were analyzed for the presence or absence of prostatic cancer in the right and left sides of the glan d and for evidence of spread either through the capsule, into the semi nal vesicles, or to lymph nodes or bone. Findings at MR imaging were c ompared with results of radical prostatectomy (20), lymph node dissect ion without prostatectomy (seven), and biopsy (67). RESULTS. Image qua lity obtained with the combination of the fast spin-echo sequence with the multicoil was judged superior to that obtained with either the co nventional spin-echo sequence with the multicoil or the fast spin-echo sequence with the body coil. Significant motion artifacts were noted in 45% of studies (13/29) performed without glucagon vs 7% of studies (3/42) performed with glucagon. In the 58 patients for whom informatio n concerning the location of tumor in either the right or left side of the gland was obtained from biopsy (39) or surgery (19), MR images al lowed cancer to be detected with 89% sensitivity and 77% specificity. Among the 20 patients undergoing prostatectomy and seven others underg oing lymph node dissection, MR imaging permitted high accuracies in pr edicting involvement of the seminal vesicles (100%), local transcapsul ar spread (85%), and involvement of pelvic lymph nodes (85%). CONCLUSI ON. Fast spin-echo imaging with a pelvic phased-array multicoil provid es high-resolution images of the prostate that may obviate an endorect al coil for the detection, localization, and staging of prostatic carc inoma.