Abstracts-part VII (Continue in Part VIII)

Abstract

INTRODUCTION A N D P U R P O S EM a g n e t i c r e s o n a n c e imaging (MRI) h a s been f o u n d to be a u s e f u l non-invasive method of d e m o n s t r a t i n g intra-2rticular structures of various joints ' . H o w e v e r , the u s e f u l n e s s of M R I i n d e m o n s t r a t i n g the changes of o s t e o a r t h r i t i s (O.A.)i n the hips has not been adequately documented. The m a i n purpose of t h i s prospective study is to a s s e s s the ability of M R I in : (a) d e l i n e a t i n g the c h a n g e s of O.A., using roentgenograms and s y m p t o m s a s c o r r e l a t e s ; (b) d e t e c t i o n of early a r t i c u l a r cartilage c h a n g e s i n a s y m p t o m a t i c older v o l u n t e e r s (over age 50), using younger n o r m a l volunteers (under age 35) a s controls. In a d d i t i o n , i n order to e s t a b l i s h a base-line for future M R s t u d y of the h i p , normal variations s u c h as the d i s t r i b u t i o n of red and y e l l o w m a r r o win the proximal f e m u r and intra-articular fat were a l s o studied. METHODST e n patients (9P, lM, m e a n age 62, range 33-78) with well-documented O . A . of the h i p s and 15 n o r m a l volunteers (9M, 6F, 9 under age 35, 1 aged 4 5 and 5 over age 50) w e r e studied.All M R scans were performed with a Diasonics M T / S 0.35T imager.For the patients with well-documented O.A. of the h i p s , all s c a n s were o b t a i n e d using a whole-body sized imaging coil, 1.7x1.7mm pixel size and 5-10mm slice thickness. For the n o r m a l volunteers, h i g h r e s o l u t i o n surface c o i l images were a l s o obtained w i t h pixel size of 0.9x0.9mmand slice thickness of 5mm. Pulse sequences used included TR10.5-2.0sec and TEa30-80msec. All patients with O.A. had roentgenograms of the h i p s within a n average of 2.2 months (range 0-4 months) of the M R examinations.A f t e r a n a l y z i n g the changes observed, a M R grading system for assessing s e v e r i t y of O.A. in the hips was developed.Using this grading system and a recognized grading system f o r roentgenograms, both with grades 0-4, 2 radiologists i n d e p e n d e n t l y graded the M R s t u d i e s and plain films separately, twice.The f u n c t i o n a l capacities of the patients were a l s o graded by the attending rheumatologist. The M R studies of the n o r m a l volunteers were carefully a n a l y z e d , concentrating especially on : (a) the thickness and continuity of the hyaline c a r t i l a g e , (b) the trabecular pattern, (c) the d i s t r i b u t i o n of red and y e l l o w m a r r o w in the proximal femur, and (d) the distribution of intra-articular fat. RESULTSunilateral total hip prostheses, therefore 18 h i p s were included in this study.There were 3, 5 and 2 patients in the Grade I V , 111 and I1 f u n c t i o n a l capacity categories respectively. The r o e n t g e n o g r a m grading s y s t e m was more accurate in predicting s y m p t o m s in the more severe cases, whereas, the MR grading was slightly more u s e f u...