I n t r o d u c t i o nThe i d i o p a t h i c myopathies ( I I M ) a r e a heterogeneous group o f d i s o r d e r s which i n c l u d e : p o l y m y o s i t i s ( P ) ; dermatomyositis (D); i n c l u s i o n body m y o s i t i s (IBM); and o t h e r d i s o r d e r s . P a t i e n t s (PTS) c l i n i c a l l y have symmetrical weakness, p a i n , tenderness, rash, fever, a r t h r a l g i a s , dysphagia, i n t e r s t i t i a l l u n g disease, m y o c a r d i t i s , and Raynaud's phenomenon.E l e v a t i o n s i n serum c r e a t i n e kinase (CK), a l d o l a s e ( A L ) and l a c t a t e dehydrogenase (LDH) a r e observed. Muscle biopsy (MB) r e v e a l f i b e r degeneration and r e g e n e r a t i o n and i n f l ammatory i n f i l t r a t e s , c o n s i s t i n g o f mononuclear c e l l s . T h i s study demonstrates t h e e v a l u a t i o n o f 33 p a t i e n t s w i t h I I M by M R I c o r r e l a t i n g t o t h e r e s u l t s o f MB and p a t i e n t s ' c l i n i c a l c o n d i t i o n and assessment (CDA) .
Met hods t h i r t y -t h r e e p a t i e n t s ( 1 5 p a t i e n t s w i t h P, 8 p a t i e n t s w i t h 0 , and 10 p a t i e n t s w i t h IBM) w i t h c l i n i c a l and l a b o r a t o r y , o r by MB (28 p t s ) evidence o f I I M were e v a l u a t e d a t 0.5 t e s l a u s i n g a T1 dependent ( T l D ) s p i n echo (SE) p u l s e sequence w i t h an echo t i m e (TE) o f12-34 msec, a r e p e t i t i o n t i m e (TR) o f 300-600 msec, a T2-dependent (T20) SE 2000/80 and STIR ( I R 1500/100) p u l s e sequence i n t h e a x i a l and coronal plane u s i n g 128 views. MRIs were reviewed i n a b l i n d e d f a s h i o n i n regards t o MB, CK, LDH, and CDA s t a t u s f o r each p a t i e n t u s i n g a 0-3 g r a d i n g s i g n a l i n t e n s i t y ( S I ) and degree o f f a t t y i n f i l t r a t i o n i n t h e muscle (O=normal, l = m i l d i n c r e a s e S I minimal i n f i l t r a t i o n , 2=increased S I moderate i n f i l t r a t i o n , 3=severe i n f i l t r a t i o n o r h i g h S I ) on a l l t h r e e p u l s e sequences. MB were performed w i t h i n a p e r i o d o f 2 weeks b e f o r e or a f t e r M R I from t h e l o w e r e x t r e m i t i e s and were graded i n a b l i n d e d manner and assigned i n f l a m m a t o r y and myopathy scores, depending on involvement (O=no evidence, l = m i 1 d , 2=moderate, 3=severe). CDA scores were d e r i v e d from p a t i e n t s ' d a t a i n c l u d i n g : CK, AL, LDH, muscle s t r e n g t h t e s t i n g , d a i l y a c t i v i t i e s and h i s t o r y . The CDA scores ranged from 0 f o r i n a c t i v e disease t o 3 f o r severe a c t i v e disease.S t a t i s t i c a l a n a l y s i s was performed by Wilcoxon a n a l y s i s and K e n d a l l ' s c o r r e l a t i o n o f CDA scores, MB scores, and M R I scores. A
McNemar's t e s t was a l s o performed comparing t h e v a r i o u s t e s t s c o r e s . ( l ) R e s u l t s O v e r a l l , M R I scores c o r r e l a t e d w e l l w i t h c l i n i c a l disea...