Original Article
REVISTA PAULISTA DE MEDICIN AJuve nile idiopathic inflammatory myopathie s:
the value of magne tic re sonance imaging in
the de te ction of muscle involve me nt
Pediatric Rheumatology section, Discipline of Allergy, Clinical Immunology and Rheumatology, Department
of Pediatrics, Universidade Federal de São Paulo / Escola Paulista de Medicina, São Paulo, Brazil
a b s t r a c t
CON TEX T: O ne o f the majo r current challeng es related to juvenile idio pathic inflammato ry myo pathy is the search fo r hig hly sensitive and specific no n-invasive metho ds fo r diag no sis as well as fo r fo l-lo w-up.
OBJECTIVES: The aim o f o ur study was to describe typical mag netic reso nance imag ing finding s and to investig ate the usefulness o f this metho d in detecting active muscle disease in juvenile dermato myo si-tis and juvenile systemic lupus erythemato sus patients.
DESIGN : Transverse study, blinded assessment.
SETTIN G: University referral unit (Pediatric Rheumato lo g y sectio n, Department o f Pediatrics, Universidade Federal de São Paulo / Esco la Paulista de Medicina).
SAM PLE: Thirteen patients (9 g irls) with dermato myo sitis, as well as 1 3 patients (1 2 g irls) with juvenile systemic lupus erythemato sus and 1 0 no rmal children (5 g irls), were enro lled in the study.
M AIN M EASUREM EN TS: Q ualitative and quantitative analyses o f g luteus maximus, quadriceps, adducto rs and flexo rs were perfo rmed and evaluated by two radio lo g ists, blinded to all clinical info rma-tio n. Spin-echo in T1 , DP, T2 and IR was used in all MRI imag es.
RESULTS: The different muscle g ro ups presented no n-unifo rm invo lve-ment in the patients. The patients with dermato myo sitis presented acute and chro nic muscular alteratio ns, while tho se with lupus presented o nly chro nic myo pathy, especially atro phy. In the dermato -myo sitis g ro up, the majo r alteratio ns were fo und in the g luteus and flexo r reg io ns (sig nal intensity and fat replacement). The sig nal in-tensity was increased in all acute myo pathies.
CON CLUSION : The qualitative and quantitative reso nance analyses are useful in detecting clinically active disease in patients with der-mato myo sitis.
KEY W O RDS: Juvenile derma to myo sitis. Juvenile systemic lupus erythemato sus. Muscle invo lvement. Mag netic reso nance imag ing .
• Maria O dete Esteves Hilário • Hélio Yamashita • Daniela Lutti • Cláudio Len • Maria Teresa Terreri • Henrique Lederman
INTRODUCTION
Idio pathic inflammato ry myo pathy syndro me is co nstituted by a hetero geneo us gro up o f diseases, o f unkno wn etio lo gy, that have in co mmo n an inflam-mato ry muscle pro cess.
It is characterized by pro ximal muscular weak-ness, elevatio n o f serum enzymes related mainly to striated musculature, electro myo graph alteratio ns, presence o f mo no nuclear infiltrate in muscles and ab-sence o f reco gnizable etio lo gy.1
This gro up o f diseases presents a large range o f histo patho lo gical findings, respo nse to treatment and clinical evo lutio n.
The principal representatives o f idio pathic in-flammato ry myo pathies are dermato myo sitis, po ly-myo sitis and inclusio n bo dy ly-myo sitis. Juvenile der-mato myo sitis is the mo st impo rtant during infancy, as it o ccurs mo st frequently and presents the mo st severe muscular inflammatio n. There are also myo -pathies asso ciated with o ther co nnective tissue diseases, especially juvenile systemic lupus erythemato -sus, sclero derma and juvenile rheumato id arthritis.
One o f the majo r current challenges related to idio pathic inflammato ry myo pathies is the search fo r highly sensitive and specific no n-invasive metho ds fo r diagno sis as well as fo r treatment fo llo w-up. Amo ng the image diagno sis metho ds, magnetic reso nance imaging (MRI) has sho wn itself to be o ne o f the best techniques fo r this purpo se and fo r muscle skeleto n disease fo llo w-up.2,3
In 1987, Kaufman et al,4
param-eters analyzed by reso nance. In later studies, undertaken mainly with adult patients, the usefulness o f this metho d in the diagno sis o f acute and chro nic inflammato ry muscle diseases was o bserved.5-7
Ho wever, altho ugh id-io pathic inflammato ry myo pathies in childho o d present their o wn characteristics, studies using MRI fo r muscu-lar evaluatio n are no t co mmo n.8-10 This fact mo tivated
us to study reso nance alteratio ns in patients with juve-nile dermato myo sitis and juvejuve-nile systemic lupus erythe-mato sus, and to co rrelate the findings quantitatively and qualitatively with the presence o f inflammato ry activity.
METHODS
The pro cedures that fo llo w were in acco rdance with the ethical standards o f the co mmittee respo n-sible fo r human experimentatio n and with the Helsinki Declaratio n o f 1975, as revised in 1983.
Design
Transverse study, blinded assessment.
Setting
Academic referral unit (Pediatric Rheumato lo gy sectio n, Department o f Pediatrics, Universidade Fed-eral de São Paulo / Esco la Paulista de Medicina).
Sample
Twenty six patients divided into 2 gro ups were evaluated o ver a perio d o f 2 years: 13 with dermato -myo sitis (9 girls) diagno sed acco rding to the Bo han and Peter (1975) criteria,11 with ages ranging fro m 5.6 to 16.6
years (mean o f 11.7 years); 13 patients with juvenile systemic lupus erythemato sus (12 girls) acco rding to the American Co llege o f Rheumato lo gy criteria,11 with
ages ranging fro m 9.3 to 16.7 years (mean 13.6). The mean disease duratio n was 4.5 years (range 1.5 to 13.6) fo r dermato myo sitis and 3.7 years (range 0.4 to 8.6) fo r lupus patients. We also calculated the mean daily co r-tico stero id do se fo r each patient during the last 6 mo nths and co rrelated it with the MRI findings. The co ntro l gro up co nsisted o f 10 healthy children and ado -lescents (5 girls), with ages ranging fro m 5.0 to 16.0 years (mean o f 11.6 years), free fro m any disease.
Diagnostic Procedures
Clinical Evaluation. The characterizatio n o f inflam-mato ry activity in the derinflam-mato myo sitis gro up was based o n the clinical parameters o f muscular strength and the presence o f altered muscle enzymes, particu-larly the creatine kinase, aspartate amino transferase, aldo lase and lactic dehydro genase. Fo r lupus patients, the Systemic Lupus Erythemato sus Disease Activity Index (SLEDAI) and the fo llo wing sco res were used:13
mild disease activity (sco re 1 to 9), mo derate (sco re 10 to 19) and severe (sco re
≥
20) disease activity. All parents gave info rmed co nsent fo r the study, which had the prio r appro val o f the lo cal ethics co mmittee.Magnetic Resonance Imaging. To carry o ut the MRI, the equipment used was a Philips 1.5-tesla Gyro scan S15, release 5.6. We perfo rmed T1-weighted and T2-weighted images with spin-echo (SE) sequences and fat suppressio n technique, with an inversio n reco very
Table 1 Qualitative Analysis score of e ach parame te r analyze d
Score
Findings 0 1
↑ muscular sig nal intensity ≤ 5 0 % > 5 0 %
↑ bio chemical shift N o Yes
Perimuscular edema N o Yes
↑ sig nal intensity o f subcutaneo us fat N o Yes Muscular atro phy ≥ 0 .7 5 < 0 .7 5 Muscular fat replacement ≤ 5 0 % > 5 0 %
Table 2 - Patie nts with de rmatomyositis, according to the numbe r of muscle groups affe cte d in the qualitative analysis
Pa tient ↑muscula r ↑biochemica l perimuscula r ↑subcuta neous muscula r muscula r fa t
signa l shift edema fa t signa l a trophy repla cement
intensity intensity
1 0 2 0 0 1 1
2 2 2 1 2 1 0
3 0 0 1 0 0 0
4 0 1 1 1 1 0
5 1 1 0 0 1 2
6 0 0 1 0 1 1
7 0 1 0 0 1 0
8 4 4 1 0 1 4
9 0 0 0 0 1 0
1 0 0 0 0 0 0 0
1 1 0 0 0 0 1 0
1 2 3 4 4 1 1 0
1 3 1 0 0 2 0 0
(IR) sequence. The T1-weighted images were acquired in the co ro nal and axial planes: SE, TR/TE o f 500-640/ 20ms, 2 to 4 acquisitio ns, 180 X 256 matrix, 10/10 mm thickness/increase and field o f view (FOV) o f 350 mm o n the axial and 500 mm o n the co ro nal. The T2 im-ages were acquired in the axial plane: SE, TR/TE o f 2500/90 ms, 1 acquisitio n, 204 x 256 matrix, 10/10 mm thickness/increase and FOV o f 300 mm. The IR images were acquired in the axial plane: TR/TE/TI o f 1900-2000/ 20/160 ms, 2 acquisitio ns, 180 x 256 matrix, 10/10 mm and FOV o f 300 mm. Each patient and co ntro l was submitted to an MRI exam (to tal o f 36). T1-weighted, T2-weighted and IR images were acquired. All images were o btained with the center in the mid-thigh.
Main Measurements
The muscle gro ups studied were: gluteus maxi-mus, quadriceps, adducto rs and flexo rs. The exams were evaluated by 2 radio lo gists who carried o ut qualitative and quantitative analysis o f the 4 muscle gro ups by co nsensus, with no kno wledge o f the patient histo ry. Fo r the qualitative analysis in T2-weighted, T1-weighted and IR, 6 types o f findings were standardized and given po ints in acco rdance with Table 1. The first 4 (signal intensity, chemical shift, perimuscular edema and sig-nal intensity o f subcutaneo us fat) are findings o f acute alteratio ns and were o bserved o n T2-weighted images. The o ther 2 parameters were o bserved o n T1-weighted and IR images. With this metho d the maximum po s-sible sco re o btainable o n evaluatio n o f each patient was 21 po ints. A lo wer sco re indicated lesser muscular pro blems. The analysis o f muscular atro phy was made based o n the relatio nship between the thigh muscle diameter and the to tal thigh diameter.
The quantitative analysis was undertaken in T2-weighted images and the signal intensity o f each in-dividual gro up o f muscles was o btained using a re-gio n o f interest (ROI) o f 0.5 cm at the midpo int o f the thigh and lo wer third o f the hip. The relatio nship be-tween intensities o f the muscle/fat signal was calcu-lated by means o f dividing the signal intensity mea-surements o f the muscle gro ups by the fat measure-ments. Fo r each muscle gro up, the mean o f the 3 mea-surements o btained in the regio n with the stro ngest signal o f the sectio n being studied was used.
Statistical Methods
The fo llo wing no n-parametric tests were used to analyze the results: Kruskal-Wallis test, exact Fisher test, Mann-Whitney test and the Friedman ranked variance analysis test. In all the tests, the level fo r the rejectio n o f the null hypo thesis was fixed at 5% (P < 0.05).
RESULTS
Muscular weakness was o bserved in 9/13 pa-tients (68%) with dermato myo sitis, o f who m 6 (46%) presented elevated muscular enzymes. The neck flexo r muscles were the mo st affected. Creatine kinase was the mo st frequently altered enzyme (83%). Disease activity was characterized in 46% o f patients.
We did no t o bserve any clinical muscle
impair-Figure 1 - Patients with juvenile dermatomyositis, juvenile systemic lupus erythematosus and controls, according to the total alterations present in the muscle groups at qualitative analysis.
Figure 2 - Patients with JDM, JSLE and controls, according to thigh muscle diameter/total thigh diameter (muscle atrophy).
ment o r muscular enzyme elevatio n in patients with lupus. As regards SLEDAI, 4 patients presented mild disease activity, 5 mo derate and 4 severe disease ac-tivity.
Magnetic Resonance Imaging
The freq uency o f alteratio ns o b served in the qualitative analysis was significantly higher in patients with dermato myo sitis when co mpared to the lupus patients and co ntro ls (Figure 1). Amo ng the variables studied, the muscle signal intensity and the chemical shift presented the mo st alteratio ns, altho ugh there was no significant statistical difference (Table 2). The statistical analysis sho wed a significant asso ciatio n (P < 0.05) between the presence o f acute findings and the dermato myo sitis gro up. One interesting o bserva-tio n was the high frequency o f chro nic alterabserva-tio ns in patients with lupus instead o f acute alteratio ns.
In relatio n to muscular atro phy, the greatest invo lvement was o bserved in patients with dermato myo -sitis: this was less pro no unced in patients with lupus, and no t present in the co ntro ls (Figure 2). Quantita-tive analysis sho wed greater invo lvement o f gluteus maximus and quadriceps in dermato myo sitis patients as co mpared to co ntro ls.
In Figure 3 the muscle/fat relatio nship mean can be o bserved fo r muscle gro ups in patients with der-mato myo sitis, lupus and co ntro ls. The co rrelatio n b etween MRI, muscular weakness and elevatio n o f muscle enzymes was determined o nly fo r patients with dermato myo sitis, as the alteratio ns were no t o bserved in the lupus gro up. Regarding muscular weakness, a statistically significant asso ciatio n with the acute alteratio ns was fo und and a tendency to wards an asso -ciatio n with the chro nic alteratio ns o f the qualitative analysis was fo und. The patients with dermato myo si-tis and mo re accentuated muscular weakness pre-sented a higher muscle/fat relatio nship and therefo re greater invo lvement in the quantitative analysis (P = 0.008).
The increase in muscle enzymes also sho wed a significant co rrelatio n with the acute changes o bserved in the MRI qualitative analysis (P=0.004). Qualitative analysis variables o nly presented a statistically sig-nificant co rrelatio n with the bio chemical shift analy-sis (P < 0.05).
Quantitative analysis sho wed a statistically sig-nific ant c o rre latio n b e twe e n highe r value s in the muscle/fat relatio nship and the raising o f muscle en-zymes (P = 0.015). In the dermato myo sitis gro up, the mean daily co rtico stero id do se was 0.59 mg (0 to 1.2 mg/kg/day) and higher do ses o nly presented a co rre-latio n with the muscle/fat rerre-latio nship (quantitative
analysis). In the lupus gro up we did no t o bserve a co r-relatio n between the mean co rtico stero id do se (0.47 mg/kg/day) and the MRI findings.
DISCUSSION
We evaluated 13 patients with juvenile dermato -myo sitis, 13 patients with juvenile systemic lupus erythemato sus and 10 no rmal children and ado les-cents, using MRI exams with the spin-echo technique, with T1-weighted, T2-weighted and IR (fat suppressio n) images. The aim o f this study was to co rrelate the clinical and labo rato ry alteratio ns with the MRI find-ings. The study was perfo rmed with 2 types o f analy-sis, the qualitative and the quantitative.
Characterizatio n o f disease activity in o ur der-mato myo sitis gro up was based o n changes in muscu-lar strength asso ciated with the presence o f elevated muscle enzymes, which will be discussed. As we kno w, muscle enzymes do no t co rrelate well with muscular strength, rashes o r muscle bio psy in so me patients.14,15
On the o ther hand muscle weakness, in chro nic pa-tients, may just reflect muscular atro phy and fibro sis related to co ntinuo us o r chro nic-recurrent inflamma-to ry disease. In spite o f all these co nsideratio ns, we decided to emplo y this criterio n, since it is widely used in the literature.4,6,16
Disease activity was diagno sed in 46% o f o ur patients with dermato myo sitis. All lupus patients pre-sented disease activity ranging fro m mild to severe, which was expected, as the gro up was hetero geneo us in te rm s o f dise ase duratio n and type o f invo lve -ment.17,18We did no t o bserve clinical muscle invo
lve-ment (muscle weakness) in these patients, as was described by o ther autho rs.19,20
in-tensity in 7 o f 8 patients with active dermato myo sitis. The “chemical shift” detected alteratio ns in 7 patients, 6 o f who m with disease activity, thereby sho wing a sensitivity o f 85.7% and a specificity o f 83.3% in the detectio n o f disease activity.
Muscular atro phy and fat replacement are quali-tative analysis findings asso ciated with chro nic muscle pro cesses. The cause o f muscular atro phy in dermato -myo sitis is multifacto rial and may be due to chro nic inflammatio n with impo rtant muscular impairment, reductio n o f physical activity during disease activity and lo ng term co rtico therapy with elevated do ses.20 It is
pro bable that these 3 facto rs co ntributed to the pres-ence o f muscular atro phy in 84% (11/13) o f the patients with dermato myo sitis. The remaining patients were no t active and were using lo w do ses o f co rtico stero ids.
Due to the small number o f findings in patients with lupus, we did no t carry o ut a statistical analysis. Nevertheless, it is interesting to no te that 41% o f the to tal qualitative analysis findings o ccurred in o ne pa-tient, who at the time o f the exam presented reactiva-tio n o f the disease, with intense general manifesta-tio ns and mo de rate dise ase activity (SLEDAI), al-tho ugh with no alteratio ns in muscle enzymes o r mus-cular strength. Chro nic alteratio ns predo minated in lupus patients, represented mainly by muscular atro -phy. This finding co uld be explained by so me facto rs, such as the reductio n in physical activity, pro lo nged co rtico therapy with high do ses, and perhaps the ex-istence o f a subclinical myo pathy.
In summary, 92.3% (12/13) with dermato myo si-tis presented so me degree o f invo lvement in the quali-tative reso nance analysis, whereas the enzyme alter-atio n was o bserved in 6 (46%). In the study o f Park et al,21 the qualitative analysis alteratio ns were present
in 81.8% o f patients, whereas the enzyme alteratio ns amo unted to 27%. These figures suggest that reso -nance is capable o f detecting muscle invo lvement in patients with no clinical o r enzyme alteratio ns, per-haps b y de te cting sub clinical dise ase activity and muscle scarring invo lvement. So me studies o f patients
1. Plo tz PH, Dalakas M, Leff RL, Lo ve AA, Miller FW, Cro nin ME. Current c o nc e p ts in id io p athic inflam m ato ry m yo p athie s: p o lym yo sitis, dermato myo sitis, and related diso rders. Ann Intern Med 1989;111:143-57. 2. Co uncil o f Scientific Affairs: Musculo skeletal applicatio ns o f magnetic
reso nance imaging. JAMA 1989;262:2430-7.
3. Co lliso n CH, Sinal SH, Jo rizzo JL, Walker FO, Mo nu JU, Snyder J. Juvenile dermato myo sitis and po lymyo sitis: a fo llo w-up study o f lo ng-term sequelae. So uth Med J 1998;91:17-22.
4. Kaufm an LD, Grub e r BL, Ge rts m an DP, Kae ll AT. Pre lim inary
with disease activity fo und reso nance alteratio ns in 100% o f cases.16,22
Quantitative analysis is in general co rrelated with acute alteratio ns in muscle invo lvement o r ac-tive disease.23 In o ur study we o bserved significant
differences amo ng dermato myo sitis, lupus and co n-tro ls in 2 muscular gro ups (gluteus maximus and quad-riceps). In the study o f Hernandez et al,22 the muscle/
fat relatio nship mean fo r 4 muscle gro ups in 4 chil-dren was evaluated at o nset and 6 mo nths after the start o f treatment. These autho rs o bserved significant differences between the muscle/fat relatio nship mean fo r the gluteus maximus, adducto rs and quadriceps o f patients with dermato myo sitis. The difference be-tween o ur findings and tho se o f Hernandez et al,22 may
have o ccurred because o f hetero geneo us muscle in-vo lvement, different degrees o f disease activity and the lo nger disease duratio n o bserved in o ur patients. In o ur study, the muscle/fat relatio nship mean varied between 0.42 and 0.46. In the study o f Hernandez et al,22 the mean values at the time o f diagno sis were
between 0.76 and 1.17 in the 4 muscle gro ups. After 6 mo nths o f treatment they o b served a reductio n in these relatio nships(0.41 to 0.61). This demo nstrates that the muscle/fat relatio nship (quantitative analy-sis) is related to acute pro cesses and that there is a tendency to no rmalizatio n o f this relatio nship during treatment.
CONCLUSIONS
Magnetic reso nance imaging is a useful metho d in the detectio n o f muscular invo lvement and in the fo llo w-up o f patients with idio pathic inflammato ry myo pathies. It can be used in diverse ways because it is able to differentiate no rmal fro m patho lo gic mus-culature, to define acute and chro nic muscle alter-atio ns and to detect and rank muscle invo lvement in relatio n to disease activity. In additio n, it is a no n-invasive, radiatio n free, painless examinatio n that can be used repeatedly.
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8. Keim DR, Hernandez RJ, Sullivan DB. Serial magnetic reso nance imaging in juvenile dermato myo sitis. Arthritis Rheum 1991;34:1580-4. 9. Hernandez RJ, Keim DR, Chenevert TL, Sullivan DB, Aisen AM.
Fat-suppressed MR imaging o f myo sitis. Radio lo gy 1992;182:217-9. 10. Chapman S, So uthwo o d TR, Fo wler J, Ryder CAJ. Rapid changes in
magnetic reso nance imaging o f muscle during the treatment o f juvenile dermato myo sitis. Br J Rheumato l 1994;33:184-6.
11. Bo han A, Peter JB. Po lymyo sitis and dermato myo sitis (parts 1 and 2). N Engl J Med 1975;292:344-7 and 403-7.
12. Tan EM, Co hen AS, Fries JF, et al. The 1982 revised criteria fo r the classificatio n o f syste m ic lupus e rythe m ato sus. Arthritis Rhe um 1982;25:1271-7.
13. Bo m b ard ie r C, Glad m an DD, Uro witz MB, Caro n D, Chang CH. Derivatio n o f the SLEDAI: a disease activity index fo r lupus patients. Arthritis Rheum 1992;35:630-9.
14. Pachman LM. Juvenile dermato myo sitis: patho physio lo gy and disease expressio n. Ped Clin No rth Am 1995;45:1071-98.
15. Law WW, Chan H, Chan YL, Fung JW, So NM, Metreweli C. MR imaging in amyo pathic dermato myo sitis. Acta Radio l 1999;40:69-72. 16. Stiglbauer R, Graniner W, Kramer PJ, Schurawitzi H, Macho ld K, Imho f
H. Po lymyo sitis: MRI - appearance at 1.5 T and co rrelatio n o f clinical findings. Clin Radio l 1993;48:244-8.
17. Tso ko s GC, Mo utso po ulus HM, Steiberg AD. Muscle invo lvement in systemic lupus erythemato sus. JAMA 1981;246:766-8.
18. Lim KL, Ab d u l- Wah ab R, Lo we J, Po we ll RJ. Mu s c le b io p s y ab no rmalitie s in syste mic lupus e rythe mato sus: co rre latio n with clinical and labo rato ry parameters. Ann Rheum Dis 1994;53:178-82. 19. Fujino H, Ko bayashi T, Go to I, Onitsuka H. Magnetic reso nance imaging
o f the muscles in patients with po lymyo sitis and dermato myo sitis. Muscle Nerve 1991;14:716-20.
20. Askari A, Vigno s PJ, Mo sko witz RW. Stero id myo pathy in co nnective tissue disease. Am J Med 1976;61:485-92.
21. Park JH, Vital TL, Ryder NM, et al. Magnetic reso nance imaging and P-31 magnetic reso nance spectro sco py pro vide unique quantitative data u s e fu l in th e lo n g itu d in al m an ag e m e n t o f p atie n ts with dermato myo sitis. Arthritis Rheum 1994;37:736-46.
22. Hernandez RJ, Keim DR, Chenevert TL, Martel W. Magnetic reso nance imaging appearance o f the muscles in childho o d dermato myo sitis. J Pediatr 1990;117:546-50.
23. He rnand e z RJ, Sullivan DB, Che ne ve rt TL, Ke im DR. MR im aging in c hild re n with d e rm ato m yo s itis : m us c ulo s ke le tal find ings and c o rre l a t i o n w i t h c l i n i c a l a n d l a b o ra t o ry f i n d i n g s . A JR 1993;161:359- 62.
r e s u m o
CON TEX TO: Um do s maio res desafio s relacio nado s as mio patias inflamató rias idio páticas juvenis está na pro cura de méto do s sensíveis e e spe c ífic o s, po ré m nã o inva sivo s, pa ra o se u dia g nó stic o e aco mpanhamento .
OBJETIVO: Avaliar o s achado s da resso nância magnética e investigar a utilidade do méto do na detecção do co mpro metimento muscular e m p a c ie nte s c o m d e rma to mio site juve nil e lúp us e rite ma to so sistêmico juvenil.
TIPO DE ESTUDO: Transversal, simples ceg o .
LO CAL: Se to r de Re uma to lo g ia Pe diá tric a do De pa rta me nto de Pediatria da Universidade Federal de São Paulo / Esco la Paulista de Medicina.
M ÉTODOS: Fiz eram parte do estudo 1 3 pacientes (9 meninas) co m de rma to mio site juve nil, 1 3 pa c ie nte s (1 2 me nina s) c o m lúpus eritemato so sistêmico juvenil e 1 0 crianças (5 meninas) no rmais co mo co ntro les. Em to das as imag ens da resso nância fo i utiliz ado o spin-eco em T1 , DP, T2 e IR e realiz adas as análises qualitativa e quantitativa do s g lúteo s máximo s, quadríceps, aduto res e flexo res. O s exames fo ram avaliado s po r do is radio lo g istas que não tiveram acesso a qualquer info rmação so bre o s pacientes.
RESULTADO S: Mo stra ra m c o mpro me time nto nã o unifo rme do s diferentes g rupo s musculares em to do s o s pacientes. Alteraçõ es a g ud a s e c rô nic a s fo ra m o b se rva d a s no s p a c ie nte s c o m dermato mio site enquanto que naqueles co m lúpus fo ram enco ntradas apenas alteraçõ es crô nicas, especialmente atro fia. As alteraçõ es mais impo rtantes (substituição g o rduro sa e aumento da intensidade de sinal) fo ram o bservadas no s g lúteo s e flexo res do s pacientes co m dermato mio site. Aumento da intensidade de sinal esteve presente em to das as mio sites ag udas.
CON CLUSÃO: A análise qualitativa e quantitativa da resso nância mag nética é útil para a detecção do co mpro metimento muscular clinicamente ativo em pacientes co m dermato mio site.
PALAVRAS-CHAVE: Dermato mio site. Lupus Eritemato so Sistêmico . Co mpro metimento muscular. Crianças. Resso nância Mag nética.
Acknowle dgme nts - We wish to express o ur thanks to Dr Yara Juliano and Dr Neil Ferreira No vo fo r statistical assistance.
Maria Ode te Este ve s Hilário, MD. Asso ciate Pro fesso r - Chief, Pediatric Rheumato lo gy sectio n, Department o f Pediatrics, Universidade Federal de São Paulo / Esco la Paulista de Medicina, São Paulo , Brazil.
Hé lio Yamashita, MD. Asso ciate Pro fesso r, Department o f Diagno stic Imaging, Universidade Federal de São Paulo / Esco la Paulista de Medicina, São Paulo , Brazil.
Danie la Lutti, MD. Pediatric Rheumato lo gist, Department o f Pediatrics, Universidade Federal de São Paulo / Esco la Paulista de Medicina, São Paulo , Brazil.
Cláudio Le n, MD. Pediatric Rheumato lo gist, Department o f Pediatrics, Universidade Federal de São Paulo / Esco la Paulista de Medicina, São Paulo , Brazil.
Maria Te re sa Te rre ri, MD. Pediatric Rheumato lo gist, Department o f Pediatrics, Universidade Federal de São Paulo / Esco la Paulista de Medicina, São Paulo , Brazil.
He nrique Le de rman, MD, PhD. Full Pro fesso r, Chief, Department o f Diagno stic Imaging, Universidade Federal de São Paulo / Esco la Paulista de Medicina, São Paulo , Brazil.
Source s of funding: suppo rted by CNPq nº 133735/93-1.
Conflict of inte re st: no t declared
Last re ce ive d: 23 September 1999
Acce pte d: 2 Octo ber 1999
Addre ss for corre sponde nce :
Maria Odete Esteves Hilário Alameda do s Anapurús, 1370/144 São Paulo /SP - Brasil - CEP 04087-004 E-mail: o dete@ no x.net
