773
CT of Primary Muscle Diseases
M . Jiddane,' J. L. Gastaut, J . F. Pellissier, J. Pouget, G. Serratrice , and G. Salamon
Seventy-five patients with a variety of muscular dystrophies
were studied using computed tomography (CT). At least 11
slices were taken in each patient, from the forearm to the lower
leg . Sufficient information was obtained to provide some CT
characteristics of several dystrophies, including Duchenne muscular dystrophy, facioscapulohumeral syndrome , limb-girdle
muscle myopathies, and myopathic dystrophies. CT promises to
be of increasing value in these areas in the future .
Computed tom ograph y (CT) has not been w idely used in th e
di agn os is and investigati on of mu sc ular dystrophies . The pauc ity of
reports in th e literaturE' bears thi s out . Th e appearance of mu scle
tissues and muscle mo rpholog y are ve ry c haracteri sti c on CT ,
however , and many of th e features th at are early indicators of
dyst ro phi c diseases (e.g., atro phi ed or pseudoatrophi ed lesions,
degeneration, or fatty infiltrations) are easil y re cognized . Whil e
many mu scular dystrophies are present at birth , some of th em d o
not manifest c linically for many years. It was our intent to determin e
if th ese dystrop hies had any useful informati on to provide on CT.
We studi ed th e CT appearan ce of muscle tissue in pati ents with a
va ri ety of mu sc ular d ystrophi es. Because thi s stud y investi gated
relatively un researc hed areas, it was our main purpose simply to
loo k for co rrelati ons of CT appearance and disease.
Subjects and Methods
Thi s wo rk is based on a study of 75 patients with a vari ety of
mu scular d ystrophi es examined at th e Neuro-Mu scular Di sease
Clinic during 198 1 and 1982 . Th e sam e procedure was used in
examin ing all pati ents. It in vo lved on e sli ce throug h th e fo rearm,
two slices thro ugh th e upper arm , two or three slices of th e scapular
girdle and pelvi s, three sli ces at thigh level, and three slices of th e
lower leg. Th e examin ation was perform ed on a CE 10,000 CT
scanner. Th e scans were studi ed prim aril y for evidence of morphologi c anomalies (atroph y and hy pertroph y) and diffused or loca l
anomalies (areas of nec rosis , fatty infiltrati on , etc. ) in th e hope th at
we could co rrelate th e appearance of ce rtain features on CT w ith
specific conditions.
Results
O ur finding s co nce rn essentiall y four types of mu scular dystrophies: Du c henne di sease ; Land ouz y-Dejerin e type facioscapul ohumeral myo pathi es; limb-girdle mu scular d ystrophy; and Stein ert
myo tonic dystroph y. Several oth er co nditions were also examin ed
(e.g., glycogenic mu sc le in filtration, co rti so nic myopath y , polymyositis), but th e data are too fragmentary to be d iscussed here.
Duchenne M usc ular Dystrophy
Alth ough many o f th e types of muscular dystrophies re lated to
th e X c hromosome have been in dividualized (Becker syndrome,
Em ery-Dreyfu s synd rome), th e most frequen t form is th at described
by Duc henne in 1868. Th e disease is present at birth , and its sign s
generall y manifest c linica ll y whe n th e c hil d is about 3 years old .
Walkin g diffic ul ties appear grad uall y during c hildh ood . Hypert rop hy
of th e ca lves occ urs earl y on, and th en th e d isease spreads to t he
rest of th e mu sculature. Because it is a genetic anomaly , th e d isease
is alm ost always recog ni zed in th e yo un g c hild , and is evidently
hereditary. Th e evolutio n is fairl y c haracteri sti c . Late wa lkin g , ca lf
hy pertro ph y, and diffic ulty in c limbing stairs or in risin g fro m a
sitting position are comm on. Th e damage fin all y reaches th e arm
mu scles and a scoli os is app ears. At about 10 years of age th e
c hild ' s mu scular d egenerati on is suc h th at he or she ca n no longer
wa lk and mu st be put into a w heelc hair. Death is usually d ue to
recurrent respiratory infec ti ons, and occurs wh en th e pati en t is
abo ut 20. Vi ctim s of th e disease also usually present so me form of
mental retard ati on. Th e di sease 's essential bi olog ic c riterion is an
inc rease in c reatine kin ase [ 1, 2 ].
Fro m an anatomopath ologi c viewpoint, th e numerous anomalies
associated w ith Duc henne mu scular dystrop hy explain the im portance of CT scan im ages. Th ese inc lude mu scle fi ber mod ifica tions,
degenerative processes, mu sc le n'ec ros is, and fat infiltrati on. At th e
end of th e di sease 's evoluti on, th e mu scle has d isappeared , leaving
in its pl ace fibrous fatty ti ss ue. Iro nically , w hen anatomi c exa minati ons are performed , th ey do not show any lesions in th e central
nervo us system ; it is th e mu scle bi opsy th at di scovers th e anomalies. El ectro m yog raph y sometim es shows fibrill ati on, b ut more oft en
demonstrates pseud omyotonic d ischarges and continual voluntaril y
disturbed traces th at are small , of short d urati on , and interfered
w ith by th e least move ment.
We examin ed eight patients, aged 4-14 yea rs. Th e length o f
diag nosed Du c henne evolution was 2-8 years. Th e pati ents examin ed at th e onset of th e di sease presen ted CT anomalies, espec iall y in the ca lf. Th ese anomalies were pse udohypert rophy and
decrease d mu scle density . Th e latt er was also foun d at th e level o f
bo th thi ghs (fig. 1). In th e cases in vo lving later stages of evolution,
all th e mu sc les we re damaged . Th ey presented an aspec t of lowered den sity , evok in g a fat infiltrati on (figs . 1 and 2).
CT examinati on all owed a ve ry precise view of lesion topog raph y
and permitted us to fo ll ow the disease ' s evolu tio n. Especiall y valuable wa s its ab ility to d istingu ish pseudohype rtrophy fro m actu al
hyp ertrop hy . In an actu al hypert rop hy, mu scle vo lume inc reases
' All authors: Laboratory of Neuroradiology , IN SERM U6, 300 Boulevard de Sain te M arguerit e, 13 009 Marse ille, France. Add ress reprin t req uests to G.
Salamon .
AJNR 4 :773-776, May / June 1983 0 195- 6 108 / 83 / 0403-0773 $00 .00 © Ame rican Roentgen Ray Society
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MISCELLANEOUS
AJNR:4, May / June 1983
Fig . 1 .-Duchenne muscu lar dystrophy. At thigh level all muscles have
di sa ppeared (arrows ), which is characteristic of disease 's late stage.
Fig. 3 .-Landouzy-Dejerine syndrome (facioscapulohumeral syndrome) in
38-year-old woman with 10 year clinical evolution. At leg level there is
disparity of third peroneal muscle on both sides (arrowheads) . Pattern is
frequently observed in this syndrome and especiall y in so-called scapuloperon eal syndrome .
Fig . 2 .-Duch enne muscular dystrophy in 9-year-old ch ild . Density of
gluteus maximus on sides is very low (arrows), while other muscles are
normal. This is usual finding in Duchenne at this stage.
Fig . 4 .-Landouzy-Dejerine syndome (facioscapulohumeral syndrome) in
36-year-old woman with 17 year clinical evolution . Slices at thigh level show
asymmetry of lesions. Involvement of posterior thigh muscle parts on right
side: biceps, semitendinous, semimembranous , gracilis, and great adductor
(arrowheads). Minor champs on rectus femoris and vastus medialis (arrows) .
and its density is normal while in a pseudohypertrophy the increased
muscle vo lume is due to a fat infiltration of muscle and the increase
of subcutaneo us fat tissue.
Facioscapulohumeral and Scapuloperoneal Syndromes
The facioscap'Jlohumeral myopathies described under the name
of Landouzy-Dejerine disease can also be included in the group of
hereditary myopathies. Scapuloperoneal atrophies belong to a
smaller and less diverse group that is distinguished by a slig htly
different neurogenic o rigin .
The facioscapulohumeral myopathies are transmitted by dominant autosomal chromosomes and especially affect the facial mimic
muscles . Difficulty in c losing the eyelid s and a smoo th appearance
of the facial muscles are two common signs. Scapular muscle
troubles appear early (difficulty in raising the arms above the head)
and progress to problems with the biceps and triceps. The deltoid
is often untouched. In contrast to Duchenne disease, hypertrophy
is not observed, and muscle damage is often asymmetrical. The
muscles of the inferior limbs are often damaged, and in severe
forms the paraspinal muscles are often attacked, caus ing lordosis.
Although the disease 's prognosis is much better than that of Duchenne disease, the infantile forms are very severe. Cardiac anomalies
are noted . The evolution is usually very slow [3]. The anatomopathologic examination shows collections of sarcoplasm between
groups of myofibril and type II fiber hypertrophy. Inflammatory
reactions and areas of necrosis are also possible. When it was
possible in our study to examine the centra l nervous system, it was
always normal.
We examined 10 patients aged 17-40. The length of evolution
varied greatly. The most common CT anomalies were located at th e
levels of the brachial biceps and triceps and the scapular girdle.
Even in the early stages, inferior member muscle damage was
almost always found . Locations of this muscle damage included the
buttocks, the thigh , and the posterior and anterior parts of the leg ;
in scapuloperoneal syndromes, the damage predominated in the
anterior part of the leg (fig. 3). For facioscapulohumeral syndrome,
the three most interesting features demonstrated by CT were the
asymmetry of th e lesions (fig. 4), the frequent inferior member
muscle damage, and the paraspinal muscle damage.
Limb-Girdle Muscle Myopathies
Thi s group of diseases consists of various conditions classified
as limb-girdle muscle myopathies by Walton and Natrass [4]. Actually , they belong to an enormous group of primitive muscle diseases that do not affect the face, are transmitted by autosomal
heredity (usually recessive or sporadic), and have a benign evolution . (Duchenne cons idered the cases he encountered to be a form
of progressive fatty muscle atrophy .) Th ey can attack both genders,
and often appear when the individual is about 30 years old. Half the
cases begin with damage to the pelvic belt; the other half wi th the
AJN R:4, May / Ju ne 1983
MISCELLANEOUS
A
Fig. 5. -limb-girdle syndrome in 6 1-year-old man after several years of
clinical signs. A, Slices at thigh level show only minor infiltration of fat in to
subcutaneous space (arrows ). Thi s is observed mainl y in me n. Mu sc les are
infiltrated symmetri cally. At same level adducto rs and vastu s lateral is are
Fig . 6 .- limb-girdl e syndrome in 22-year-old woman . Infiltration of subcutaneous fat is enormous (arrows ), w hich is commo n in women w ith lim bgi rd le syndrome. All muscles of thigh are affected on both sides (arrowh eads ).
scapu lar mu scles. Both th e should er and pelvic girdles are attac ked
eventuall y. Generally, 10-20 years intervene betwee n th e onset of
th e disease and major wal kin g diffic ulties. It is sometim es very
diffic ult to make a diagnosis between hereditary myopathi es or
acquired myopathi es (e .g ., polymyositi s or endocrin e o r toxic myositis) and mu scle disease having a spin al origin (Kug elberg-Welander disease). Generall y, th e pelvic and should er girdle mu sc les are
th e most frequently damaged , but arm and thigh damage are also
common . Electromyograph y shows myopathi c c hanges (potentiall y
small , short-term , and polyphasi c ), whi c h are som etim es associated
with an omalies su ggesting denervati on [5]. Th e anato mopath olog ic
examination demonstrates th e myofibril size va ri ati ons, necrosis
zones of mu scl e fibers, fatty excess, and fib rous infiltrati on processes . Biologi cally , th ere is an inc rease in serum c reati ne kinase .
We examined 25 patients w ith lim b-girdle mu scle myo pathi es (1 5
women and 10 men) , ag ed 20 -65 . Th e length of evolution va ri ed
greatly . In most cases th e mu scle damage in vo lved th e perihum eral,
th e buttock , and esp ecially the thi gh and calf mu scles.
CT revealed a number of interesting facts, inc luding the symmetri cal distribution of th e mu scle damage as opposed to fac ioscapulohumoral myo pathi es (fig s. 5-7), th e importance of fat infiltration
in damaged musc les (fig s. 6 and 7), th e importance of the inc rease
775
B
extensively invo lved by abnorm al infi ltrati on (arro wh eads), which here proved
to be glycogeni c. B, Disparity on both sid es of paraspinal mu scles (arrowheads ).
Fig. 7. - l imb-g irdle synd rome. Patient had c li nica l hypertrophy of mu scles of leg . Soleu s on both sides is totally infilt rated (arro wheads ). On ly
gastroc nemi us (arrows ) appears partl y normal. Thus, biopsy mi ght prove
normal on the latter muscle.
(especiall y in wo men) of subcutaneous fa t ti ssue (fi gs. 5A and 6)
and the frequent attack on spinal mu sc les (fig . 5 B) . Th e attack on
th e mu scles of th e thigh and of th e leg ' s posteri or musc les was
especiall y notabl e (fig . 7).
Myotonic Dys trophy (S tein ert Disease)
A different c lin ical entity from Thom sen co ngenital myotonia,
Steinert disease is hereditary and transmitted by domin ant autosom al c hrom osome [6] . It attac ks both genders and has a slow ,
progressive evolution . The d isease espec ially affec ts the d istal,
face , and neck muscles . In the severe form s there may be ph arynx
and laryn x damage . In eve ry case , th e myoto nic ph enom ena are
c harac terized by an abn ormall y lon g decontraction after a vo luntary
contraction or perc ussion of th e mu sc le; th e slowness of its return
to a relaxed state is remarkable. Wid espread oth er mu sc le damage
ca n be noted : ca rdi ac, ocular, endocrine, and digestive. Elec tromyog raph y is c harac terized by myoto nic disc harg e. Th e anatomopath olog ic examination reveals a proliferati on of nuc lei, mu scular
atroph y, fibrosis, and sometimes fat infiltratio n into th e mu sc le. Th e
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MISCELLANEOUS
atrop hy invo lves ty pe I fibers in parti c ular, and th ere are also a
great many neuromu scular and spin al in serti ons.
Seven pati ents with myotonic dystro ph y were examin ed . In each
case th e evolution was at least 4 yea rs long , and CT always revealed
an important lesion in th e distal mu scle. In many cases th e damage
also co nce rn ed th e quadri ce ps mu scles . CT c harac teri stics of myo tonic dystro ph y incl uded a decrease in mu sc le volum e, irregul ar
hypodensity o f th e mu scles, and spin al mu scle d amag e.
Discussion
Th ere are few reports of CT examin ati on of mu scles. In 19 7 6 th e
va lue of CT was assessed for th e stud y of neuro genic mu scular
atrophi es in vo lving last cra ni al nerve palsies (Wolf, unpubli shed
presentation). In 1 979, Bulcke et al. [7] reported on CT examin ation
of 24 norm al subjec ts. Th ey proposed a density scale for every
mu sc le, but did not report on any path olog ic cases. In 198 1 , Bulc ke
et al. [8] p resented th e res ults of a CT examin ati on of three cases
of Becker di sease. In 19 77 , O 'Doherty et al. [9 ] performed CT on
10 patients. Five had Du c henne mu scular dystroph y, one had
facioscapul ohumeral dystroph y, two had Kug elberg-Welander syndrome, one had subacute polymyos iti s, and one had sarco id myopath y.
We have tri ed to show th e va lue of CT examin ation for certain
kind s of mu scu lar dystroph y. CT can detect damag ed musc les, and
it ori ents bi opsy an d electro myograph y better th an does a c linical
examin ati on. In some cases it can p rovid e a nearl y co mpl ete report
on th e lesions and d esc ribe their evolution. For each of th e diseases
co ncern ed , it o ffers new elements th at are not revealed by traditio nal c linica l data, elec tromyog raph y, or bi opsy.
AJNR :4 , M ay/ June 1983
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