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T HIS E XH IB IT , A SELECT ION O F TU E NEURORAD IO LO GY AND COM PU TED TOMOGRAPHYPAN EL S , W A S EXH IB IT ED A T THE 67TH SC IEN TIF IC A SSEM BLY AND ANNUAL M EETIN G OF

T HE RA DIO LO GIC AL SOC IETY O F NO RTH AM ER ICA , N OVEM BER 15-20 , 1 981 , C H ICAGO ,ILL INOIS .

C om pu ted tom ography in th eeva lua tion o f le s ion sa r is in g in and around th e sa crum

So lomon Ba tn i t zky , M .D .Ian Soy e , M .D .E rro l L ev ine , M .D ., P h .D .H ilton I. P ric e , M .D .K elly Z . H art, M .D .

In gen era l, com pu ted tom ography is su perio r to o th er stud ies fo rth e eva lua tion o f th e sa crum becau se o f its a b ility to defin e th ein tra - an d ex tra osseou s ex ten t o f a les ion p rec ise ly .

In trod uc tion P rim ary le sion s o f the sac rum are re la tive ly in freq uen t. In m any in -stances, the sym ptom s they p ro duce a re n onsp ec if ic an d vagu e. In add itio n ,the sac rum is a d ifficu lt b one to exam ine by conv en tiona l rad io g rap h ictechn iq ues b ecause o f its ang u la tion an d inh eren t cu rva tu re and becau seo f the su pe rim pos itio n of ove rly ing b ow e l con ten ts . U s ing ro u tine d iagn ostictechn iq ues, such as p la in rad iog raph y , co nven tio na l tom og raph y , rad io -n uc lide bon e scann in g , m ye log raphy and b arium enem a stud ies , sm all le sion so f th e sac rum and its su rro und ing a rea m ay be m issed . In the case o f largele sion s, the ex ten t o f bon e an d so ft tissue invo lvem en t m ay no t be accu rate lydem on stra ted us ing th ese techn iques.

F rom the D epa rtm en t o f D iag nos tic R ad io log y , T he U nive rs ity o f K ansas C o lleg e o fH ea lth S ciences an d H o sp ita l, K ansas C ity , K an sas.

A ddress rep rin t requests to S o lom on B atn itzk y , M .D ., D ep ar tm en t o f D iagnos tic R ad i-o lo gy , The U niv ersity o f K an sas C o llege o f H ea lth S c iences and H osp ital, R a inbow Bou lev arda t 39 th S tree t, K ansas C ity , K ansas 66 103 .

500 R ad ioG rap h ic s N ov em ber 1982 Volum e 2 , N um ber 4


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B atn itzky , e t a t .CT of le sion s in th e sacrum

W ith the adven t o f com pu ted tom ograp hy (C T ), an im portan t new In trodu c tionim ag in g m oda lity h as becom e ava ilab le fo r the eva lua tion o f le sion s in andaround th e sac rum . C T can accu ra te ly and c lea rly d el ineate the ex ten t o fbone and so ft tissue inv o lvem en t. T h is capab ility p erm its accu rate p lann in gof su rg ica l and rad ia tio n th erapy . In th e case o f m alig nan t les ions, fo llow upCT scans are ex trem e ly v alu ab le fo r a sse ss ing the e ffec ts o f rad ia tio n th erapyan d chem o the rapy and fo r de tectin g tum or recu rren ce .

The sp ecific ity o f C T do es n o t m atch its sen si tiv i ty , an d sp ec ific tissued iagno sis is no t alw ays po ssib le on th e basis o f th e CT fin d ing s alo ne .

The u se o f va riou s co n tra s t m ed ia (in tra thecal m etriz am id e , in trav en ou siod ina ted con tras t m ateria l, and ba rium ) in con ju nc tion w ith CT scan n in gp rov ide s ad d itio na l v a luab le in fo rm a tio n rega rd in g the ex ten t o f a les io n .

45 SACRAL LES ION S D EM ONSTRA TED BY COM PU TEDT OMOGRA PHY

A . CONGEN ITAL1. S acra l C y st (3 )2. Pe rineu ral S acra l C ys ts (1 )

B . T RAUMA S1 . F rac tu re (2 )

C . PR IM ARY TUMORS1. S ac ro co ccyg ea l T e ra tom a (3 )2 . C hordom a (3 )3 . G ian t C e ll Tum or (2 )4. A neu ry sm a l B one C y st (1 )5. Ex trasp ina l E pendym om a (2 )6 . In trasacra l S chw annom a (1 )7. H em ang iom a (1 )8. Ew in gs T um o r (1 )9 . O ssify ing F ib rom a (1 )

D . M ETA STA SES FROM D ISTANT S ITES (1 6)E . LO CALLY RECURREN T RECTA L CARC INOM A (3)F . M ISC ELLANEOU S LES ION S

1 . P age ts D isease (1 )2 . D ura l E c ta sia (1 )3 . S p ina l D y sraph ism w ith L ipom ato us In filtra tion (2 )4. In f lam m ato ry L esions (Tube rcu lo sis) (1 )

V o lum e 2 , N um ber 4 N ov em ber 19 82 R ad ioG rap h ic s 501


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Ana t omyBASE O F SACR UM

PELV IC V IEW

S U P E R I O RAR TJ C UL AR P RO C ES S

SUPERIORA RT IC ULAR PRO CESS

SACRALCANAL

DORSALP EL VI C SU R FA CESURFACE

SAGITTALSECTION

ANTERIORSACRALFORAMEN

SACRAL POSTERIORC AN A L SA CR A L

FORAMENTRANSVERSESECT IONTHROUGH S i

POSTERIORSACRAL FORAMINA ..

DORSAL V IEW

I H I A T U SC O C C Y G E A LC O R N U

R ad ioG raph ics N ov em be r i98 2 V olum e 2 , N um ber 4

No rma l

502

B a tn itzk y , e t a t.CT o f le sion s in th e sacrum

PELV IC , SAG ITTA L, DORSAL , AND TRANSVERSE V IEW SOF SACRUM AND COCCYX .

F igu re iPe lv ic , s ag ittal, do rsa l an d transve rse v iew s o f thesac rum and coccyx .

FILUMTERU INALE.

R ECTUM \\ S

SAG ITTAL SECTION THROUGHM ID SACRUM AND PELV IS .

Figu re 2S ag ittal s ec tion th roug h m id sac rum and pe lv isdem on stra tin g the re la tionsh ip o f the sac rumand coccyx to th e rectum and b lad de r.


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B atn itzky , e t a t .

V o lum e 2 , N um ber 4 N ovem ber 1982 R ad ioG raph ics 503

CT o f le sion s in th e sacrum

F igu re 3A x ia l C T scans th ro ug h th e sac rum dem onstra tin g the n o rm al an atom y o f the sac rum .1. F irst sac ra l segm en t (S i) 5 . P o ster io r sacra l fo ram en2 . A la of sac rum 6. F ifth sac ra l segm ent (S5 )3 . Sacra l cana l 7 . G rea te r sc iatic no tch4 . A n te r io r sac ra l fo ram en 8 . P irifo rm is m usc le

No rma lAn a t omy


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A

a 2

.,._.

b+- V

C

R ad ioG raph ics N ovem be r i98 2 V olum e 2 , Num ber 4

No rma lAn a t omy

B a tn itzk y , e t a t .C T of lesio ns in the sa crum

F igu re 4C T scans th ro ug h the low er sac ra l and co ccy geal are a w ith b arium in the re c tum (arrow h ead ) an d co lon (arrow s).O pen a rrow po in ts to the b ladd er.

F ig u re 5Sag itta l (A and B ) and co ro na l (C ) reco nstruc tion o f the lum bosac ral a rea . Th e sp in al can al (arrow h ead s), s ac rala la (a rrow s) an d sac ro ilia c jo in ts (open a rrow ) a re clea rly seen .

504


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CT o f le sio ns in the sacrum

In tra sac ra l cy st , an terio r sa c ra l m en in go ce le , in trasacra l m en ing oceleand sac ral ex tradu ra l cys t a re d iffe ren t v a rian ts o f the sam e cond ition . T heya ll are b a sica lly ara ch no id cys ts aris in g w ith in th e sac rum and com m un i-ca ting w ith th e suba rachn o id space in m o st in s tan ces. B ecau se o f the ir pu l-sa tile na tu re, they m ay prod uce erosio n and ex pansio n of the sac ra l cana lan d m ay reach a la rge size . T hey m ay ex tend in to the p elv is , p rod uc ingb lad de r o r re cta l sym p tom s. In som e in s tan ce s , th ey m ay b e asso cia ted w ithp art ia l ag en es is o f th e sac rum (F igu re 6 ).

Sac ra tCys t

B atn itzky , e t a l.

V o lum e 2 , N um ber 4 N ov em ber i9 82 R ad ioG raph ic s 505

F ig u re 6ACT scan o f a 20 yea r o ld m a le w ho w as adm itted fo r eva lua tion of lef t h ip pa in , d em onstra tes a la rg e cy stic le sio nw ith in th e sac rum , exp an d in g the sacra l c an al . T h e dens ity o f th is le s ion is th at o f sp ina l flu id .

F igu re 6BM etrizam ide m yelo g raph y reveals the d is ta l en d o f the d u ra l sac(a rrow h ead ) to be effa ced and d isp la ced to th e le ft. T he d ura l sa ccom m un ica te s w ith th e sac ra l cy st v ia a th in ch an ne l (a rrow s).Som e con tra st m a te ria l is seen in the low e r po rtion o f th e cys t (o pena r rows ) .


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F igu re 7CL ate ral lam in og ram o f the sac rum afte r them ye log ram rev ea ls accum ula tion and re-ten tio n of the con tras t m a te ria l in th e pen-neu ra l cyst.

506 R ad ioG raph ics N ovem be r 1 982 V olum e 2 , N um be r 4

B a tn itzk y , e t a t .CT o f le sions in the sa crum

Pe r ineu ra lSac ra lCys t

Cysts o f the ne rve roo t shea ths ap pear a s localized , d is ta l d ila ta tions o fthe ro o t shea th tha t m ay fill w ith th e con tra st ag en t du ring m ye log raph y .A ltho ugh they m ay be fo und a t o the r leve ls , th ey m o st comm on ly occu r inthe low e r lum ba r an d upp er sac ra l roo ts. T h ese cys ts a re freq uen tly m ultip le ,and th e m a jo rity a re a sym ptom a tic . T hey m ay , on occas io n , c au se localizedth inn ing and ero sion o f th e ad ja cen t bo ne (F ig u re 7) .

F igu re 7ACT scan at the S i lev el d em ons tra te s scallo p ing and e rosio n o f thepos ter io r a spec t o f the sac ra l cana l p oste rio rly (a rrow heads); thee ro sion is m o re m arked on the righ t side .

F igu re 7BL a tera l m y elo g ram dem on stra te s the m u lti-p le , pe rin eu ra l s ac ral cys ts (arrow head s).

F igu re 7DCT scan pe rfo rm ed a fte r the m yelo g ram revea ls a c -cum ula tion of the co n tras t m ate r ial (a rrow heads) inth e reg io n of th e sca llop in g .


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V olum e 2 , N um ber 4 N ovem ber 1982 R ad ioG raph ics 507

B a tn itzk y , e t a t.CT of le sio ns in the sacrum

M any in ju r ie s o f the sacrum and coccyx are e lusiv e, and rad io lo g ica lex am ina tion by conv en tiona l m e thod s is frequen tly unrew ard ing (F ig u re8).

T r a uma

F igu re 8AA nten opos ten io r roen tgeno gram o f th e sacrumdem onstra tes a righ t-s ided fra ctu re (arrow head s).T h is fra ctu re w as n o t v isib le on the la te ra l v iewo f th e sac rum .

F ig u re 8BThe ex ten t o f th e fra ctu re is b et ter ap p rec ia tedw ith C T , w h ich reveals an und isp laced fra c tu reo f th e rig h t sa cra l a la (a rrow h eads). In m any in -stan ces, an assoc ia ted hem a tom a m ay b e d em -onstrated , a lthou gh it is no t seen in th is ca se .


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Sac rococcygea lTe ra toma

F ig u re 9ACT scan in a 32 year o ld fem ale rev ea ls a w ell m arg ina ted ,m ultilo cu lated cystic m ass.

F ig u re 9B (be low )CT scan of the pe lv is o f a 2 year o ld fem ale dem ons tra tes ex-tensio n of a large , m a in ly so lid , m a lignan t te ra tom a (a rrow -heads) in to the le f t bu tto ck . T he b ladd er (a rrow s) and rec tum(open a rrow ) a re d isp laced by th e tum of.

w ,,

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-

1

2 3

F ig u re 9C2 year o ld m ale w ith a large , p red om inan tly cystic te ra tom a ex tend ing in to the pe lv is . i-ax ia l scan , 2 and 3-coro na lrecon stru ctio n scan s and sag itta l recon stru ctio n scan .

508 R ad ioG rap h ic s N ov em ber i9 82 V o lum e 2 , N um ber 4

B a tn itzky , e t a t.CT of le sio ns in th e sacrum

Sac rococcygea l te ra tom as a re ra re le sio ns fo un d in on e in 3 5 ,000 l ivebir ths . They are , how ev er, th e m ost comm on sac ral tum or in ch ild ho od . T h eyd ev elop from m ult ipo ten tia l c e l ls in H ensen s no de th at m ig ra te caud ally .T he m ajo rity a re no ted at b ir th , b u t they m ay be fo und in in fancy or ev ench ild hood . R a rely , they m ay p resen t in adu lthoo d . T hey o ccu r 4 tim es m orefrequ en tly in fem ales th an in m ale s . S ix ty p ercen t con ta in ca lc ific a t ion s tha ta re v isib le o n p la in film s , and th e se ca lc ified tum ors a re u sua lly , a lthou ghno t in va riab ly , ben ign . C y st ic tum ors , to o , a re m o st o ften ben ign , b u t tum orsw ith p redom inan tly so lid com pon en ts a re u sua lly m a lignan t. D e fin itivetre a tm en t co ns is ts o f su rg ic al rem ov al o f th e tum o r and ex tirpa tion o f theco ccyx . B en ig n tum ors m ay recu r if incom plete ly rem oved and have a p o-ten t ia l fo r m a lig nan t transfo rm ation .

C T can b e espec ia l ly u se fu l in de te rm in ing w he th er a te ra tom a is cy s tico r p redom inan tly so l id -an im po rtan t d is tin c tion in v iew of the g rea terlik elihoo d o f m a lig nancy in so lid le s ion s (F igu re 9 ).


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G ian t C e llT umo r

F ig u re 1O ACT scan of the sac rum of a 53 yea r o ld fem a le d em onstra tes a la rge , exp an s ile tum or de -stro y ing m o st o f the sac rum . T he rec tum (a rrow heads) is pu shed fo rw ard b y thet umor .

F igu re lO BCT scan of the sac rum o f a 36 yea r o ld fem a le d em onstra tes a la rge , exp an s ile m ass inv o lv in g the left sa cra l a la an dth e le ft po s terio r ilia c w ing .

Vo l ume 2 , N um ber 4 Novem ber 1982 Rad ioGraph ic s 509

B a tn itzky , e t a t.CT of le sion s in the sacrum

G ian t ce ll tum ors occu r m ain ly in pa tien ts b etw een th e age s o f 2 0 an d40 an d m o st o ften in vo lve the lo ng bon es . T h ere is a fem ale p red ile c tion .T h ese tum ors , even tho se tha t in itia lly appea r h is to lo g ica lly to be com ple te lyb en ign , a re cap ab le o f sh ow ing m a lign an t cha rac te ris tics . G ian t ce ll tum oro f the sp in e is ex trem e ly rare . T he few th at do o ccur a re m ost com m on ly seenin th e sac rum , bu t few er th an 5% affect th e sacrum . R ad io log ic ally , the tum oris cha racte riz ed b y a ly tic p ro ce ss w ith litt le o r no bone p ro du ction . T he reis a w id e tran si tion zo ne from pa tho log ica l to no rm a l bo ne (F ig u re 10 ).


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Cho r d oma s

-.- -, N. S. - S S

t

---n: : ._.. .L

F ig u re hAThis 2 8 yea r o ld m a le had a cho rdom a resected o ne yea r p rio r to th is scan . P la in f ilm s and tom ogram s w ere norm a lon fo llow up . T h is tiny i cm lesio n (arrow head s) w as seen on th e C T scan and proved to be a recu rren t tum o r.

F igu re h hBThe la rge s iz e , so lid n atu re an d predom in an tly m id lin e lo ca tio n o f a sac ra l cho rdom a is ex em p lified in th is 70 yearo ld p atien t. T he re is a lm o st com ple te destruc tion o f the sac rum .

510 R ad ioG raph ics N ov em be r i98 2 V o lum e 2 , N um be r 4

B a tn itzk y , e t a l.CT o f le sion s in th e sa crum

C ho rdom as a re re la tiv ely un comm on tum o rs . T h ey a rise from res ts o fth e no tocho rd an d m ay be fou nd a t any po in t from the clivu s to the coccyx .A pp rox im a te ly 50% o rig ina te in the sac rococcygea l are a; 3 5% , in the c liv usand 15% , in the re st o f the ve rteb ra l co lum n . C ho rdom a is th e m o st com m onprim ary tum or o f th e sac rum . Th e ave rag e age at d iagno sis o f the sac ro -coccygea l g roup is 56 years , w ith a m a le -to -fem a le ra t io o f tw o -to -o ne . T h etum or beg in s a s a loca lly de s truc tiv e le s ion o f the sac rum or coccy x . L ate r,it w ill cause b on e exp an s ion an d m ay break th rou gh th e b on e co rtex in anyd irec tio n , p rodu c ing ex trao sseo us so ft issu e m asse s th at m ay becom e ex-t remely la rge . S u rg ica l re sec tio n a lon g w ith ad juvan t rad ia tion the rap y orchem o the rapy re su lts in a five y ea r su rv iva l o f 66% o f pa tien ts. T he tum orm ay recu r lo ca lly o r m ay deve lop d istan t m eta sta se s. In one se rie s , m eta sta ticsp read occu rred in 28% of pa tien ts w ith sacro coccy gea l cho rd om as (F igu re11) .


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B a tn itzk y , e t a t.

V olum e 2 , N um ber 4 N ovem ber 1982 R ad ioG raph ics


Cho r d oma s

F igu re h lCTh i s 63 y ea r o ld m ale h ad a sac ral ch o rd om a d iag nosed in i9 75 . T he tum or co u ld n ot b e com ple te lyrem oved , and h is C T scan in 19 79 d em on stra te s cen tra l de s truc tio n o f the sacrum w ith ex ten s iono f the tum o r sup e rio rly an d la te ra l ly o u t o f the sac rum in to th e rig h t il iac w in g (arrow h ead s).

F igu re liDTw o yea rs la ter, a repeat C T scan d em onstra tes de s truc tio n o f m o st o f the rig h t s id e o f th e sac rum and th e su pe rio riliac w ing on th e righ t alo ng w ith a h uge so ft tissu e m ass .

511


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Aneu r y sma tB one C yst

F ig u re i2AL ate ra l tom og ram of th e sac rum in an 1 1 yea r o ld fem ale reveals an exp an silemas s inv o lv in g 52 and S3 . Th is le sion w as cu re tted an d then treated w ith rad ia tionthe rapy . H isto lo gy co nfirm ed th e d iagno sis o f an an eu ry sm a l bo ne cys t.

F igu re i2BCT scan of th e sac rum 9 m onths la te r dem on stra te s a ly tic les ion in the le ft s ide o f the sac rum ,ex tend ing acro ss the m id lin e . T he re is co ns id erab le re ac tiv e sde ros is aro un d th e le s ion . T hefea tu res a re tho se o f a hea ling aneurysm al bon e cyst.

512 R ad ioG rap h ic s N ov em ber i9 82 V o lum e 2 , N um ber 4

B atn itzky , e t a t .CT of le sio ns in the sacrum

A neu rysm a l b on e cys ts a re b en ign le sion s w ho se e tio log y ha s been thesub jec t o f m uch deba te and con trov ersy . S om e con side r th em to be neo-p la sm s ; o th ers be lieve th is con d ition to be alw ays re lated to traum a. T he agegro up a ffec ted ran ge s from in fancy to the fou rth d ecade o f life , th e m a jo rityoccurring in th e second and th ird d ecades. T he re is a fem ale p red ilec tion .A lth ough the m ajo rity o f le sions ar ise in the sh afts o f lon g bon es, ap p ro x i-ma t e l y th re e to fo u r p e rcen t o f c ase s are foun d in th e sp ina l co lum n , in -c lud ing th e sac rum . R ad io log ica lly , the re is a lo ca liz ed ra refa ct ion an d ex -pans io n o f th e inv o lv ed bone w ith th in n ing o f the co rtex . T h e neu ra l arch esa re m ore com m only affe cted th an th e v erteb ra l b od ies . T h ere m ay be en -c ro achm en t on the n eu ral cana l by the les io n , resu lting in com pre ss ion o fth e du ra l sac . C ure ttage u sua lly resu lts in cu re . R ad io the rap y is a lso u sed ,pa rticu lar ly in sp ina l le sion s (F igu re 12 ).

:A


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5 U # {149}4 .5

-I

Vo l ume 2 , N um ber 4 N ovem ber i98 2 R ad ioG rap h ic s 513

B atn itzky , e t a l.C T o f le sion s in th e sacrum

H em ang iom a is a ben ign , v ascu la r neop la sm . T h e sp in al co lum n , m o stoften th e th o raco lum ba r a rea , is the s ite o f p red ilec tio n , pa rticu la rly inw om en ov er m idd le ag e. T h e sac rum , how eve r, m ay ra re ly b e inv o lv ed . T herad io log ic al app ea ran ce o f sp in al h em ang iom a is cha rac te rized by a co a rse ,m edu lla ry pa tte rn in vo lv ing a ll o r the m a lo r po rtion o f a v erteb ra l body an dfrequ en tly ex tend in g in to the n eu ra l arch . In co n trad is tinc tio n to P age tsd isease , the se tum o rs d o no t re su lt in ve rteb ra l en la rgem en t, and no co rtic a lth icken in g occu rs (F ig u re 13 ).

H emang i oma

F ig u re h3AC onven tion al tom og rap hy of the sac rum ofa 58 y ea r o ld fem ale show s the typ ica l ra-d io lo g ica l app ea ran ce o f a r igh t-s id edhem ang iom a . N o te the cha racte ris tic coa rsetrabecu la r pa tte rn o f bon e in the reg io n o fthe tum or.

F igu re h 3BCT o f the sac rum also rev eals th e ty p ical appea rance o f a hem ang iom a .


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514 R ad ioG raph ics N ovem ber i9 82 V olum e 2 , N um be r 4

B a tn i tzk y , e t a l.CT of le sio ns in the sacrum

Ext ra s p ina lE p e n dymoma

Sp ina l ep endym om as orig in ate eith er from th e ependym al lin ing o fthe cen tra l c ana l o f th e sp ina l co rd o r from the ependym a l ce ll c lu sters o fthe filum te rm ina le . Th ey a lm o st a lw ays p resen t e ithe r a s in tram edu llarytum o rs o r a s tum o rs o f th e conu s m edu llar is-cau da equ in a reg ion . The latte rlocation is the m ost com m only inv o lv ed , and n ea rly 9 0% o f p rim a ry sp in alep en dym om as a rise in th is a rea .

E pendym a l cells m ay b e fo und in the coccy geal lig am en t as w e ll as inh ete ro top ic p osition s. It is , the refo re , no t su rp ris in g th at epend ym om as m ayra re ly occu r in ex tra sp in al lo ca tion s.

E x trasp ina l epend ym om as a re fou nd in tw o cha rac te ris tic loca tions :in th e so ft tissue p oste r io r to the sacrum , o r in th e pe lv is an te rio r to the sacrum( in the re tro re c ta l space). E pen dym om as arising in eith e r lo ca tio n m ay in -v ad e and destroy the sac rum . In co n trast to the p ictu re seen w ith the comm onsuba rach no id cau da equ ina ep en dym om a , th e ex tra sp ina l ep en dym om aapp ears o n m yelo g rap hy as an ex trad ura l le sion im p ing in g on the dura l sa cfrom be low (cau dad ) e ithe r an te rio rly o r p os te rio rly .C om p lete su rg ica l rem ova l sho u ld be a ttem p ted in a ll c ase s . A lth oughpos topera t ive su rv iva l tend s to b e lo ng , the se tum ors cha rac te ris tica lly recu rlo ca lly , and they tend to m e tasta size system ica lly m ore frequen tly than thein tradu ral v arie ty (F igu re 14 ).

F ig u re h4AConven tio na l tom ogram o f th e sac rum in a S i y ea r o ld fem a le d em onstra tesdestruc tion o f the an ter io r w all o f the sac rum . T he pos ter io r sac ra l w a ll isth in ned bu t in tac t. T he re is a lso destruc tion of th e in fe ro pos ter io r po rtionof the b ody of S i. N o te re sidu a l pan top aq ue in the d ista l thecal sac ou tlin ingthe upp er p o le o f the tum or.

F ig u re h4BLum bar m ye log ram reveals an ex tradu ra l d e fec t p rod uced by th e upp er p o leo f th e tum or ind en ting the in fe rio r aspect o f the du ra l s ac .


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5-

. .,,.

-

,- 5- 4,S

5- _5_,__..__l............... .,- V

F ig u re i4DCT scan in a 54 yea r o ld m a le w ith recu rren t epend ym om a d em ons tra te s a la rg e m ass d estroy ing th e le f t sac ra l a la( arrow head s). T he po s terio r lam inec tom y de fec t from th e p rev iou s su rg ery is a lso seen .

V olum e 2 , N um ber 4 N ov em ber 19 82 R ad ioG rap h ic s 515

B a tn itzk y , e t a l.CT of le sion s in the sa crum

Ext ra sp ina lE p e n dymoma

F igu re h 4CCT scan a t th e leve l o f S i and 52 d em on stra te s a large an te r io r sac ra l m ass destro y ing th e an te r io r w a ll o f the sac rum .The m ass ex tend s in to the pe lv is , d isp lac ing th e rec tum to the rig h t (arrow h ead s).


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516 R ad ioG raph ics N ov em ber 19 82 V o lum e 2 , N um be r 4

B atn itzky , e t a t.CT o f le sion s in th e sacrum

Sac ra tS c hwa nnoma

A lth ou gh schw annom as are comm on n eop lasm s fou nd th ro ug hou t thesp in al cana l, th e occu rren ce o f the se tum ors in th e sacra l c an al is un com m on .T hey are ben ig n tum ors , bu t they m ay p rod uce exp an sion an d e ros io n o fthe sac rum and m ay ex tend in to th e re tro re cta l sp ace (F ig u re 15 ).

F ig u re h5ALa te ra l v iew o f th e sac rum o f a 28 yea r o ld m a le d em onstra tesa large , expansile le sio n of th e sac rum .

F igu re i5BCT scan a t the L4 and L 5 leve ls dem on stra te s an ex tradu ra l m ass d isp la c ing th e m e triz am id e fi lled th eca l sac tow a rdsth e rig h t side (arrow head s). A t L 5 th e re is a com p lete b lock to the flow of the m e tr izam id e, an d no m e trizam id eis seen a t th is leve l. T h e sp in al can al is a lso m ark ed ly w idened at th is leve l.


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F igu re i5CCT scan a t the S i and S 2 leve ls reveals a la rge , de s truc tiv e mass w ith in th e u ppe r sacrum w ith e ros io n o f the po s terio rco r t ex .

Vo l ume 2 , N um ber 4 N ovem ber 1 982 R ad ioG raph ics 517

B atn itzky , e t a t.C T o f le sion s in th e sacrum

Sac ra lS c hwa nnoma

F ig u re i5DCT scan o f th e low e r sacra l are a d em on stra te s ex ten s ion o f th e tum or (arrow head s) in to th e pe lv is. T he rec tum (a rrow )is d isp laced an te rio rly to th e r igh t side . T he rig h t u re te r is d isp laced la te ra lly .


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EwingsT umo r

F ig u re i6AA n tero po s terio r rad io g raph o f the sacrumof a 15 y ea r o ld m a le rev ea ls a ly tic lesio n inth e rig h t sid e o f the sac rum w ith pe r-m ea tive m arg ins.

A

518 R ad ioG raph ics N ovem be r i9 82 V olum e 2 , N um ber 4

B a tn itzky , e t a l.CT of lesio ns in the sacrum

Ew in gs tum or is a h ig h ly m a lig nan t bo ne neop la sm tha t a ffe c ts p atien tsbe tw een fiv e an d 30 years o f ag e ; th e in cid en ce be in g g rea te s t be tw een fiv ean d 13 years o f ag e . T he tum or h as a d is tinc t p red ile c t ion fo r m a le s. M orethan 50% o f the se tum o rs occu r in the low e r ex trem itie s o r pe lv is , a lth ou ghany bon e o f th e body m ay be inv o lved . The sac rum is in vo lv ed in abou t f ivepercen t o f cases (F ig u re 16 ).

: :_

F igu re h6BCT o f the sac rum dem on stra te s th e de s truc tiv e le s ion a ris ing in the righ t sa cra l a la . T he le sion ex tend sm edia lly in to the body of the sacrum . T he re is an assoc ia ted so ft tissu e m ass (arrow head s) invo lv ingth e ilio psoa s m uscle on th e righ t an d d isp lac in g the rig h t u re te r m ed ially (arrow ). T h e tum or a lsoinv o lves the po ster io r a sp ec t o f the sac ro ilia c jo in t (open arrow h ead ).


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B a tn itzky , e t a l.CT of le sions in th e sacrum

O ssify ing fib rom as a re ra re les io ns inv o lv ing p rim a rily th e pa ran asa ls in uses , face and m and ib le . T he sac rum is a m o st u nusu a l site fo r th is tum or(F igu re 1 7).

Oss i fy ingF i b r oma

9 x SN::.:

Vo l ume 2 , N um ber 4 N ov em ber 1 982 Rad ioGraph ic s 519

F igu re i7AA n te ro po s terio r rad io g raph of the sac rum o f a 49 yea r o ld fe -m ale reveals an irreg u la r, ex pans ile m ass in the righ t s ide o f th es ac rum.

F igu re i7BCom pu ted tom og ram s d em on stra te th e ex ten t o f th is le sion , I ts sc le ro tic bo rde r is w e ll seen . N o te tha t the tum orhas destroyed th e righ t m arg in o f the sp ina l cana l. N o so ft tissue com pon en t is iden tified . H isto lo g ically th is m asspro ved to b e an o ssify in g fib rom a.


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Metas ta t icNeop la sms

M eta s ta t ic n eo p lasm s fo rm ed the la rge s t g roup of les io ns in th is se ries(1 6 p atien ts ) . T h e s ite s o f the p rim a ry tum ors w ere :

322222111

F igu re 18AM eta s ta t ic anap la s tic thy ro id carc in om a.

520 R ad ioG rap h ic s N ov em ber 19 82 V o lum e 2 , N um ber 4

B a tn itzk y , e t a t .CT o f le sion s in th e sa crum

Brea s tL ungKidneyCo lo nCerv ixU nknow n prim aryUte rusThyro idS tr ia ted m usc le

A ll o f the observed m e ta static le sio ns w ere ly tic , w ith v ary in g d egreesof b one d es tru ct ion an d ex pans io n (F igu re 18 ).


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5__.

I

- 5

B atn itzky , e t a t.

Vo l ume 2 , N um ber 4 N ovem ber 1982 R ad ioG raph ics 521

CT of le sions in the sa crum

Metas ta t icN e op t a sms

F igu re h8BM eta s ta tic squ am ous ce ll c arc inom a from ce rv ix .

F igu re h8CM etas ta tic rena l ce ll ca rcin om a .


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;;_S .# {14 9}

;,..

522 R ad ioG rap h ic s N ovem ber 19 82 V o lum e 2 , N um ber 4

B a tn itzk y , e t a t.CT of le sions in the sa crum

Recur ren tRec ta lCa rc inoma

T hree p a tien ts w ho h ad prev ious ly had resec tion s o f rec ta l ca rcin om asw ere fou nd to h av e recu rren t d isease w ith sacra l in vasion on CT scann ing .Th e tum ors recu rred in the so ft tissu es o f th e p re sacra l sp ace an d in vadedthe sacrum (F igu re 1 9 ).

F igu re 19This 62 y ea r o ld m a le had had an abdom inope rin ea l re sec tio n fo r ca rcin om a of the rectum . CT d em ons tra te s a la rg e ,ex pans ile , d es tru c tive les io n o f th e low er sac rum , secon da ry to lo ca l re cu rren ce o f th e re cta l c arc in om a.


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Page t sD i s ea s e

*:

4S!_#{149}

F ig u re 20AA nte rop os te rio r rad iog rap h o f the sacrum of a 62 yea r o ld fe-m a le revea ls sc le ro sis and th ickened trab ecu lae cha rac te ris tico f P ag ets d ise ase .

.. -- .. . -S. . # {149} {149 } S _5 S

Vo l ume 2 , N um ber 4 N ovem ber 1982 R ad ioG raph ics 523

B a tn itzk y , e t a t.CT of le sio ns in the sacrum

Pag ets d isease is a com m on d isease o f b on e of un know n e tio log y inw h ich the no rm a l bo ne a rch ite c tu re is g re at ly a lte red b y bon e re so rp t ionan d new bon e ap po sit ion . T he bone s m o st com m on ly affe c ted a re the pe lv is ,fem ur, tib ia , sp ine and sk u ll. S p ina l invo lv em en t by Page ts d ise ase occu rsm ost com m on ly in th e lum bar sp ine an d sac rum . T he d ise ase m ay a ffec t on lyon e bone , o r m ay b e w ide sp read and haph aza rd in d is trib u tion (F ig u re20) .

F igu re 20BA com pu ted tom ogram o f th e sac rum dem onstra te s m a rked bony sc le ros is and th ick en ing o f th e co rtex .


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1 .. Y,: S

4 . .

F ig u re 2 hBA fte r an in tra theca l in jec tion o f m e tr izam ide , d isp lacem en t o f th e d ural sac an te r io rly and tow ard the le ft s ide isdemonstrated .

524 R ad ioG raph ic s N ov em be r i98 2 V olum e 2 , N um ber 4

B a tn itzk y , e t a t.CT o f le sion s in the sacrum

Sp ina lDys raph i smwi thL ipoma tousInfi l t ra t ion

Sp ina l dy sraph ism rep re sen ts a w idesp read spectrum of v e rteb ral ab -e rra tion s. T hey m ay be asso c ia ted w ith m ye lo dysp las ia, a cong en ital d iso rd erof th e fo rm ation o f th e sp ina l co rd an d ne rv es . T he low er lum ba r sp in e andsacrum is the com m ones t s ite o f in vo lvem en t.

F a tty tissue in th e ex trad u ra l com pa rtm en t and sp in al c an al is com -m on ly assoc ia ted w ith sp ina l dy srap h ism . T h is lip om a tou s m a teria l m ayex tend in to th e in trad u ra l com pa rtm en t an d in to the co rd and filum ter-m ina le (F igu re s 2 1 and 22).

F igu re 21ACom pu ted tom ogram s sh ow m arked w iden ing of the sac ra l cana l w ith th in n ing and absen ce o f fu sion o f the poste r io re l emen t s .


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:-

1

,S ,.& A

Vo lum e 2 , N um ber 4 N ovem ber 1982 R ad ioG raph ic s 525

B a tn itzky , e t a l.CT of le sions in th e sa crum

Sp ina lDys raph i sm

F igu re Z iCCT of th e low e r lum ba r sp ine d em onstra tes ex ten s ion o f the lipom a to us m a teria lmen t .

in to the in trad u ral com part-

F ig u re 2 iDSag itta l re co ns tru ction o f the low e r lum ba r an d sac ra l reg io ndemons t ra tes th e l ip om a to us m ass in th e sac rum , w ith ex tens ionin to th e in trad u ral com partm en t in the low er lum bar a rea . T hein tra th ecal m etrizam ide can be c le arly seen in th e low e r lum -bo sac ra l reg ion (arrow heads).

F ig u re 22CT scan a t th e leve l o f S i in a new born fem ale d em onstra tesw iden in g o f the sacra l cana l and absence of th e p oste rio r e le -m en ts o f the sac rum . N ote the d en sity (a rrow heads) in the le f tposte r io r a sp ec t o f the sac ra l cana l rep resen tio ng lipom a tousm a ter ia l. T he CT scan is reve rsed to b lack o n w hite . Th is ishe lp fu l in d is tingu ish ing bon e and so ft tissu e de tail.


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I

Du r a lEctas ia

F ig u re 2 3AAnteropos te r io r rad iog rap h o f th e sacrum in a 1 2 y ea ro ld fem ale w ith n eu ro fib rom a tos is show s m arkedw iden in g o f th e sac ra l fo ram in a (a rrow head s) andw iden in g o f the in te rped icu la te d is tan ce a t L 4 an dL 5.

F ig u re 23BM yelog rap hy rev ea ls du ral ec ta sia w ith the d is ta l endo f the d ural sac w id en ing in to tw o large , la te ra lly sit-ua ted sac ra l m en ing oce les th at a re re sp on s ib le fo r thep la in fi lm find ing s abo ve .

.

526 R ad ioG raph ic s N ov em be r 1 982 V olum e 2 , N um be r 4

B atn itzky , e t a t.CT of le sio ns in the sacrum

D ura l e cta s ia w ith en larg em en t o f the sp ina l c an al is a com m on fin d in gin neu ro fib rom a tos is . T h is m ay be local ized to on e o r tw o segm en ts , bu t m o recomm on ly , m u lt ip le segm en ts are in vo lved . T h e d orsa l and lum ba r reg ion sare the m ost com m only inv o lv ed s ites (F ig u re 2 3 ).


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S__ __S_ (

-

B atn itzky , e t a t.

Vo l ume 2 , N um be r 4 N ov em be r i982 R ad ioG rap h ic s 527


F ig u re 2 3CCT a t the L 5 , S i an d 52 lev els d em on stra tes w iden ing o f the sp ina l cana l, tog eth er w ith th e m ark edsac ra l fo ram in al en la rg em en t. A lso , no te th e la rge , pe lv ic n eu ro fib rom a (a rrow heads) invo lv ing theb lad de r w all . T he op en a rrow po in ts to th e u te rus . M u ltip le cu tan eo us neu ro fib rom as (arrow s) a re alsoseen in the b u ttocks are a .

Du r a lEctas ia


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B atn itzky , e t a t.CT of les ions in the sa crum

Summ ary A w id e sp ec trum o f les io ns inv o lv ing the sac rum has b een p re sen ted .T h ese ex am p les h av e been selec ted from a series o f 45 pa tien ts w ho w ereexam ined by C T and o th er rad io g raph ic techn iq ue s. In m any ca se s , C Tpro v id ed im portan t in fo rm ation th at co u ld no t be o b ta ined by o th er m e tho ds .A ltho ugh C T u sua lly do es n o t pe rm it o ne to m ake an exac t p ath o lo g ica ld iag nosis , it is the m o st v alu ab le techn ique fo r d em on stra ting bo th the in -t raosseous an d ex traosseo us ex ten t o f a le s ion . C T h as e stab lished itse lf as anim po rtan t new im ag ing m od ali ty fo r the eva lu atio n o f les io ns in an d a rou ndthe sac rum .

Refe rence s 1 . D ah lin DC . B one Tum ors: G ene ral A sp ec ts an d D ata on 6221 C ases. C ha rle s C T hom as,Sp rin g field , Illin o is , 19 78 .

2 . D eS an tos LA , G o ldste in HM , M urray JA , W allace S . C om puted tom og raph y in the eva l-u atio n o f m uscu losk ele ta l neop la sm s. R ad io log y 1978 ; 1 28 :8 9 -94 .3 . M oran tz RA , K ep es JJ , B atn itzky S , M aste rson B J. E x tra sp ina l ependym om as : R epo rt o f

th ree case s. J N eu ro su rg 1979 ; 51 :3 83-39 1 .4 . N a id ich D P , F reedm an M T , B ow erm an JW , S ieg e lm an SS . C om pu ter ized tom ography

in the eva lua tion of th e soft tissue com pon en t o f b ony le sio ns o f the pe lv is . S k el R ad io l 197 8 ;3 :144-148 .

5 . R en gach ary SS , O B oyn ick P , K arlin CA , B a tn itzky S , P rice H I. In trasac ral ex tradu ra lcomm unicatin g a rachno id cy st: C ase report. N eu ro su rge ry 1981 ; 8 :2 36-24 0 .

6 . R en gach ary SS , O B oyn ick P , B a tn itzky S , K ep es JJ . G ian t in tra sac ra l schw annom a: Caserepo rt. N eu rosu rge ry 1 981 ; 9 :57 3-5 77 .

7 . Sch ey W L , Shko ln ik A , W hite H . C lin ical and rad io g raph ic cons ide ra tion s o f sacc roco c-cy geal te ra tom as: A na lysis o f 26 new cases an d rev iew of the lite ra tu re . R ad io log y 1977 ;125 :189-195 .

8 . Sm ith J, W ixon D , W atso n RC . G ian t ce ll tum or o f the sacrum : C lin ica l and rad io log ica lfeatu re s in 13 p atien ts . J C anad A ssoc R ad io l 1 974 ; 3 0 :34 -39 .9 . Turne r M L ,. M u lhe rn CB , D alin ka M K . L esio ns o f the sac rum : D ifferen tia l d iag nos is and

rad io lo g ical ev a lua tion . JAM A 1981 ; 24 5 :27 5-277 .

F igu re 6B prev ious ly appea red in Neurosurgery 1981 ; 8 :23 6-2 40 ; F igu re s 14A , C &D prev iou sly appea red in Neurosurgery 1981 ; 9 :573 -5 77 , and F igu re s iSA , B & C prev iouslyap peared in The Jo urn a l o f N eu rosu rgery 1 97 9; 5 1: 38 3- 39 1.