tc, espacion extra peritoneal , normaly colecciones liquidas

8/7/2019 TC, Espacion Extra Peritoneal , Normaly Colecciones Liquidas

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AJR :1 59 , N ov em be r 19 92 CT O F EXTRAPER ITONEAL SPACE 937

com pa rtm en t a h em orrhag e is in from th e c lin ic a l h is to ry ;con ve rse ly , an a tom ic loca liz a tio n by CT , a lon g w ith assess-m en t o f o the r pe rtine n t fea tu res , o fte n a llow s accu ra te p re -d ic tion o f th e c lin ic a l h is to ry . U rinom as a re m os t fre quen tlyloca liz ed to th e pen iren a l sp ace . A b sce ss o r in fec ted flu id ca nbe found in any o f the com pa rtm en ts . E x trapan cre a tic flu idc olle ctio ns a ss oc ia te d w ith p an cre atit is , in clu din g w ell-c irc um -scn ibed pseudocys ts , a re m ost comm on in the an te rio r pa ra -ren a l space , bu t a re no to rio us fo r c ro ss ing fasc ia l b ounda rie sa nd ca n be foun d in a ll re trope riton ea l com pa rtm en ts . E xcep tfo r h igh -a ttenu a tion co lle c tio ns ind ica t ing a n a cu te o r su b -a cu te hem a tom a , som e re trop e rito nea l flu id co lle c t ion s w illre qu ire p ercu tan eou s asp ira tio n fo r de fin it ive d iag nos is .

Periren a l SpaceThe pe rirena l space is the la rg es t o f the th re e re tro pe rito -

ne a l com pa rtm en ts , a nd on CT scans it is ea s ily id en t ifie d asa d is tin c t spa ce in a lm o st a ll pa tien ts . A lthou gh th e fa t w ith inthe pen iren a l sp ace is o ften dep ic te d a s a fea tu re less co rn -po nen t, som e ana tom ic te x tb ooks m en tio n weak trabe cu laetha t co nne c t th e rena l ca psu le to the ren a l fasc ia , and on C Tscan s Fe ld be rg [1 4 ] n o ted linea r s truc tu res w ith in the n o rm a lpe n ire na l fa t. K u n in [1 5 ], how eve r, firs t sy s tem a tica lly de -s cn ibed m ultip le fib rous Iam ella e o r sep ta tha t d iv id e th e re g ionin to d iffe re n t com pa rtm en ts . A lthou gh these b rid g in g sep taa re o ccas iona lly v is ib le on C T scans o f no rm a l pen irena l fa t,they a re m o re ea s ily v isu a lized when th ey be com e th ic ken edby flu id o r by o th e r ab no rm a litie s . S om e o f th ese se p tacon nec t th e an te rio r to the pos te rio r le ave s o f the re na l fasc ia ,o the rs a rise from the ren a l capsu le and e xten d to th e fasc ia ,a nd s till o the rs a ris e from the capsu le a nd a re a rrang ed m oreo r less pa ra lle l to th e ren a l su rfa ce . Am ong the la s t g ro up isthe so -ca lled pos te rio r ren o ren a l sep tum , a s tru c tu re run n in gfrom th e an te ro la te ra l to the p os te rom ed ia l aspe c t o f th e re na lcap su le (F ig . 5 ). W ith ca re fu l s c ru tin y , the reno rena l se p tumcan p robab ly be de tec ted in abou t 1 0% o f a bdom in a l C Texaminat ions .

B e fo re the po s te rio r ren o ren a l sep tum w as reco gn ized , itw a s tho ugh t th a t subcapsu la r a nd ex tracapsu la n h em a tom aw ou ld be ea s ily d is tin gu ishe d on C T scan s. A su bca psu la rh em a tom a w as imm ed ia te ly co n tig uou s to th e re na l p anen -chym a , usua lly fla t ten ing its n o rm a l co nve x b o rde r, a nd typ i-ca lly p rese rv in g a la ye r o f pe riren a l fa t be tw een its p e riph e ra ledg e and th e n ea rb y rena l fasc ia . A n ex tracapsu la r p en irena lh em a tom a , on the o the r han d , typ ica lly p rese rve d a laye r o ffa t be tw een its inne r b o rde r and th e edge o f th e rena l pa nen -chym a and w as usua lly co n tiguo us w ith the ren a lfasc ia . K u n in[1 5 ], h ow eve r, show ed th a t the p os te rio r reno re na l sep tumcan con fin e a n ex tracapsu la r h em a tom a and de fo rm the rena lp a ren chym a in a m anne r tha t ca n eas ily m im ic the appea ran ceo f a su bcapsu la r co lle c tio n . D is tin c tio n o f a subcapsu la r he -m a tom a from an e xtracap su la r h em a tom a con fine d b y thep os te rio r ren o ren a l sep tum is usua lly d iffic u lt. T he sub ca p -su la r loca tio n o f a h em atom a can be p red ic ted w ith con fide nceon ly if the po s te rio r ren o ren a l sep tum is id en t ifie d as a d is tin c ts tru c tu re , sepa ra ted by a laye r o f fa t from the ou te r b o rde ro f the h em a tom a [16 ] (F ig . 6 ).

W hen con fined p rim a rily to the pen iren a l sp ace , acu te h em -o rrha ge is o fte n d ue to b lun t ab dom ina l tra um a o r to a

rup tu red abdom ina l ao rtic ane u rysm . In the pnese nce o f anabdom ina l a o rtic an eu rysm , ide n tif ica tio n o f a cu te h em o r-rhag e in the pen iren a l space is d iag nos tic o f an eu rysm a lrup tu re [1 1 1. In te rru p tio n o f the d is tin c t ca lc ified on nonca lc i-fle d wa ll o f the a neu rysm is o ften id en t ifia b le a nd usu a llyind ica tes the s ite o f rup tu re [1 7 ]. B lun t abd om ina l tra um a isano the r comm on cause o f acu te pen iren a l hem orrha ge , o ftenassoc ia ted w ith re na l con tus ion , la ce ra tion , on in fa rc tio n . Acom b ina tion o f h is to ry , p hys ica l f ind ing s , an d CT fea tu reso ften e as ily le ads to a co rrec t d iagn os is in th ese tw o comm ond iso rde rs . C T fea tu res in c lu de h igh -a tten ua tion m ate ria l in te r-spe rse d w ith fa t in th e p e rire na l sp ace . W ith the p a tien tsup ine , th e b loo d typ ica lly assum es a dependen t c rescen t-sha ped con fig u ra tion w ith in the po s te rio r po rtion o f th is co rn -pa rtm en t. L ike m ost p en ire na l flu id co lle c tio ns , the b lo od isusu a lly m a rg ina ted po s te ro la te ra lly by the p os te rio r re na lfa sc ia an d poste rom ed ia lly by the psoas m usc le . T h e pe rin ena lfa t o ften has a sp icu la ted o r fe a the ry appea ra nce as the flu idsp re ads a long the unde rly in g n e tw o rk o f se p ta .

S p on ta neous subcap su la r an d pen irena l h em a tom as a reuncom m on bu t c lin ica lly im po rtan t, b eca use th ey o ften m d i-ca te an unde rly ing re na l ne op lasm . Rena l ce ll ca rc inom a (F ig .7 ) and re na l an g iom yo lipom a a re each th e cause in ab ou t30% o f ca ses ; th e rem a in ing ca se s a re caused b y a va rie tyo f va scu la r, in flam ma to ry , c ys tic , an d hem ato log ic d iso rde rs[1 8 ]. B e lv il le e t a l. [1 9 ] rece n tly repo rted a la rg e se ries o fcases eva lua ted w ith C T . In itia l C T exam ina t ions show ed ad is t in c t m ass in 1 2 (6 7% ) o f th e 1 8 cases , w ith CT cha rac te r-is tic s tha t sug ges ted the co rrec t d iagn os is in 1 1 cases . In theo the r s ix pa tien ts (3 3% ), a d is c re te m ass w as no t se en , andth e cause o f hem o rrh age w as no t c le a r in f ive o f th e s ix . Tw oo f th e f ive unde rw en t fo llow -u p C T , w h ich show ed ren a l ce llc a rc inom a in bo th . In th e rem a in ing th ree pa tien ts w ho hadno C T fo llow -up , exp lo ra to ry su rge ry show ed a 1 .5 -cm rena lce ll c a rc inom a in o ne , a 5 -cm ang iom yo lipom a in th e second ,a nd no abno rm a lity in the th ird .F o r pa tien ts w ith a spon ta neou s pen irena l h em a tom a inw hom a m ass is no t d e te c ted on in itia l C T , se ria l ren a l C Texam in a tio ns a re an a lte rna t ive to exp lo ra to ry su rge ry in o rde rto avo id u nne cessa ry neph rec tom y in pa t ien ts w ith be n ig nd isease o r n o re na l d ise ase . S uch an app ro ach , o f cou rse ,n ece ss ita tes fo llow -up s tud ies un til th e hem a tom a is co rn -p le te ly reso rbed o r un til a sp ec ific cause is de te c te d andcha rac te riz ed . A s Bo sn iak [1 8 ] has em pha s ized , m e ticu lou sa tten tio n to o p tim a l CT techn ique is m anda to ry , becausesm a ll rena l ce ll ca rc in om as can o th e rw ise escape de tec tio n .CT m ust be se lec tiv e ly pe rfo rm ed us ing th in (5 mm o r less)sec tio ns , bo th b e fo re and a fte r IV in jec tio n o f a bo lus o fc on tra st m a te ria l.

W hen u rin e con tinu es to le ak in to th e re tro pen iton ea l space ,an en cap su la te d co lle c tion o f la rg e p rop o rtio n can de ve lop .Th is co lle c tion is comm on ly te rm ed a u rinom a [2 0 ], bu t m an yo th e r nam es ha ve been used , inc lud ing un in ife rous p en irena lpse udo cys t [21 ]. O bstruc t ive unopa thy is the m ost comm oncause , b u t bo th abdom ina l tra um a and su rg ica l o r d ia gno s ticins trum en ta tio n a lso can lea d to u rin a ry ex trava sa tion . P rio rrepo rts h ave em phas ized the freq uen t tem po ra l rem o ten esso f th e ca use o f un in om a from its de tec t ion [20 ]. A s u re te ra lob s tru c tion is o fte n de com presse d by fom ice a l ru p tu re a ndpye lo s in us back flow [2 2 ], it is no t su rp ris ing tha t a u n in om a


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F ig . 6 .-S ub cap su la r ren a l hem a tom a . C Tscan show s that poste r io r reno rena l s ep tum(w hite a rr ow ) is s epara ted by a th in la y er o f fa tfro m hem atom a (H ) an d th ic ken ed ren al cap su le(b la ck a rro w).

Fi g. 7.-CT scan of peri renal or subcap sularre na l h em atom a du e to a rup tu red rena l ce ll c ar -c inom a . R o un de d c a rc inom a (T ) is s im ila r in ap -p earan ce to ad ja cen t h em ato ma (H ).

oT

F ig . 8 .-P e rire na l u rin om a . D e la yed C T sca n15 m m a fter iv in je c tio n o f c on tra s t m a te ria lshows lo cu la t ion s o f ex tra vas ated con tras t m a-terial ( a r r owheads ) ad jacen t to d ila ted rig h t u re -te r (u ) an d in p er iph ery o f rig h t pe rire na l s pace .

938 KO ROBK IN ET AL . A JR :15 9 , N ovem ber 199 2

is typ ica lly lo ca ted in the pen inena l s pace . T he w a ll o f aun inom a , fo rm ed by th e su rroun d ing rena l fa sc ia , is v is ib lyth ic ken ed on C T , re fle c ting the fib ro tic in flamm a to ry p rocessin duced by a ch ron ic u rine co lle c t ion [2 1 ]. A d ila ted re na lco lle c tin g sy s tem is seen in v irtu a lly a ll c a ses in w h ic h theun inom a is con fin ed to the p en ire na l space . U nenhan ced CTw ill u su a lly show a flu id co lle c tio n o f w a te r a ttenu a tion , bu ta fte r IV in je c tio n o f con tra s t m a te r ia l, a tte nua tio n can inc reasep rog re ss ive ly a s u rin e opac ifie d w ith con tra s t m ed ium en te rsth e u n in om a [21 ] (F ig . 8 ). In th ese ca se s the con tra s t m ed iumm ay la ye r w ith in the d ependen t po rtion o f th e u rinom a . A l-th ough the s iz e o f un inom as va r ie s , th e y a re som e tim esm ass ive , re p re sen tin g som e o f th e la rges t pe r ire na l flu idco lle c tion s . In fre quen tly , u rin om as accum u la te in lo ca tion sou ts id e the pen ire na l space , u sua lly because o f u re te ra l d is -ru p tio n caused by su rge ry , in s trum en ta tio n , o r pene tra tin gin ju rie s in fe rio r o r d is ta l to th e co n fin es o f the ren a l fasc ia .

An te rio r P a ra rena l SpaceU n like th e pen in ena l an d pos te rio r pa ra re na l sp ace s , the

an te r io r pa ra rena l space con ta in s so litt le fa t th a t it is d ifficu ltto iden tify a s a d is tin c t com pa rtm en t on C T e xce p t a t th es ites w he re it c on ta in s the a lim en ta ry trac t s truc tu re s o run le s s it is d is te nded by flu id . T he ve ry e x is te n ce o f a d is tin c tan te r io r pa ra rena l s pace com pa rtm en t w ith in the re tro pen ito -neum has been cha lle nged , la rge ly on deve lopm en ta lg rounds , b y D odds e t a l. [2 3 ], w ho em phas ized its em b ryo -lo g ic o rig in a s a n in trap en iton ea l com pa rtm en t. M o st au tho n i-tie s , h ow eve r, ha ve no t sup po rted D odd s h ypo thes is [24 ].

F lu id co lle c tio n s in the an te r io r pa ra rena l s pace a re m o recomm on on th e le ft s id e , w he re they a re a lm os t a lw aysassoc ia ted w ith in flamm a to ry d isea se o f the pancre a tic ta il.W hen found in the rig h t an te r io r pa ra rena l space , flu id isusua lly d ue to e ithe r pa ncre a tic in flam m a to ry d isea se o r toduodena l in ju ry on perfo ra tio n . D uodena l pe rfo ra tio n can beca use d b y pep tic d isease , tra um a , o r in s trum en ta tion (e sp e -c ia lly e ndo scop ic sp hm ncte no tom y ). F lu id in the le ft an te rio r

p a ra re na l spa ce is usu a lly ea sy to de tec t. It o fte n s ilhou e tte sa ll o r m os t o f th e an te r io r re na l fa sc ia on C T and w ill u sua llye ffa ce th e p os te rom ed ia l a spe c t o f the d escend ing co lon .D e te c tio n o f flu id in th e n igh t an te r io r pananena l space is m o resub tle and d iffic u lt to id en tify : th e an te r io r re na l fa s c ia is no teasy to ide n tify w ithou t flu id , a nd w hen p rese n t the f lu id d oesno t a lw ays d is tr ib u te itse lf a lo ng the fa sc ia . F lu id is o fte nlo ca liz ed to th e an te rio r pa ra ren a l sp ace s im p ly by be ings itu a ted be tw een the live r, g a llb la dde r, k id ney , and duo -denum . T he p re sence o f gas w ith in the n igh t an te rio r pana rena lspa ce a fte r traum a o r sph inc te ro tom y is v irtu a lly d ia gno s tico f a duodena l pe rfo ra tio n (F ig . 9 ). W e a re unce rta in if thep rese nce o f f lu id a lo ne , w ith ou t a ssoc ia ted ga s bubb le s , ca nre su lt from duodena l in ju ry w ith ou t pe rfo ra tio n , th u s a llow ingco nse rva t ive m anagem en t ra th e r th an su rg ica l in te rven tion .B ecause the an te rio r and pos te rio r pa ra rena l sp aces co n -ve rge w ith in the pe lv is be low the cone o f rena l fa s c ia , it h a sbeen th ough t th a t panc rea titis flu id m ig ra ted in fen io r ly in th ean te r io r pa ra rena l space and then supe rio rly in th e pos te r io rpa ra rena l s pace ; th is w ou ld exp la in the flu id com m on ly seenpos te rio r to the le ft k idne y . R ap to pou los e t a l. [9 ], how eve r,h ave a rg ued co nv inc ing ly th a t sm all s ep ta l fibe rs , conne c tingth e la tenocona l to the an ten io r rena l fa s c ia , ane p robab lyd is ru p te d by p ro teo ly tic enzym es in se ve re acu te pan crea titis ,re su ltin g in re tro rena l e x ten s ion o f flu id in to the po ten tia l c le ftb e tw een the tw o m a jo r la ye rs o f th e pos te rio r re na l fa sc ia .T h is p rodu ces the cha ra c te ris tic w edge -shaped appea ranceo f th e re tro rena l flu id , w ith com p res s ion bu t p re se rva tio n o fth e fa t w ith in the pos te r io r pa ra rena l space (F ig . 1 0 ). T hus ,a lth ough it s im u la tes flu id in the pos te r io r pa ranena l s pace ,th e pancrea titis flu id pos te rio r to the k idney ac tua lly rem a insin th e a n te rio r p ana rena l sp ace . Th is ha s obv iou s c lin ica lim p lica tio n s if p e rcu taneous flu id d ra in age is cons ide red . F lu idw ith in the pos te rio r para rena l space its e lf, a lth ough unusua lin a cu te p an cre at itis , m ay occu r v ia com m un ica tio n be tw eenthe an te rio r and poste rio r p a ra ren a l spaces be low the coneo f rena l fa s c ia (a s descr ib ed ea rlie r) on v ia enzym atic d is ru p -t ion o f th e la te roco na l fasc ia , a llow in g d irec t co n tig uou sex tens ion.


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AF ig . 9 .-A b s c es s in a n te rio r p a ra ren a l s pa ce .C T scan show s flu id and gas bubb les (A ) be tween

d uo de num , l iv e r, an d righ t k idn ey . A n te rio r re na lf asc ia ( arrows) fo rm s pos te rio r bo rd er o f ab scess .In trap eriton ea l a sc ite s su rro unds live r.

B

F ig . 1 0 .-R e tro ren a l ex ten s io n o f p an c re a ti tis flu id .A, C T scan shows flu id (F ) in le ft an ter io r p ara rena l sp ace extend ing po ste rio r to k id ney , p ro du c in ga c ha ra cte ris tic w ed ge -s ha pe d a pp ea ra nc e.B , D iag ram show s flu id ( ha t c hed area) d is s ec t ing lay ers o f po sterio r re na l fas c ia . AP S = an ter io r

pa raren a l s pace , C = descend in g co lon , LC F = la te roco na l fas c ia , PR F = tw o la ye rs o f p os te rio rr en al f as cia .

AJR :1 59 , N ov em be r 19 92 CT O F EXTRAPER ITO NEAL SPACE 939

P os te rio r P a ra rena l S paceThe pos ten ion pana ren a l spa ce is ra re ly the s ite o f an iso la ted

flu id co lle c t ion b eca use it con ta in s on ly fa t. A s de sc ribe dea rlie r, it is u ncomm on ly in vo lved in cases o f seve re a cu tep anc rea t itis . It is o ccas iona lly the s ite o f sp on ta neous h em -o rrhag e in pa tie n ts o n an tic oag u la tion the ra py o r w ith ab lee d in g d ia thes is , o ften in assoc ia t ion w ith b loo d in o th e rex tnap en itone a l com pa rtm en ts . T h e po ste rio r p a ra re na l sp acecan a lso b e in vo lve d by ex trape riton ea l hem orrha ge th a toccu rs a fte r pe rcu tan eou s ca the te riza tion p rocedu res v ia thefem ora l vesse ls , m os t comm on ly ca rd iac ca the te riz a tion [8 ].B lood is though t to ex tend su pe rio rly from the penvascu la nshea th v ia the p reve s ica l ex trape rito nea l sp ace to the in fra -re na l ne tnop en itone um , and the n in to th e pos te rio r pa ra rena l,an te rio r pa na ren a l, o r pe n ire na l spaces . S im ila r e x te ns ion o fp us from an ex trap en itone a l pe lv ic ab scess can occu r. B loodin th e p os te rio r p a ra ren a l space from a rup tu red ao rt ic ane u -ry sm is usua lly ove rshadow ed b y the m uch la rg e r am oun t inth e p en ire na l sp ace .

P e lv ic Ex trap e riton ea l SpaceA ssessm en t o f flu id in th e ex trap en itone a l com pa rtm en ts o f

the p e lv is a nd its d if fe ren tia tion from pen itone a l co lle c tion s isb es t accom p lish ed by an unde rs ta nd in g o f the pe rtine n t fas -c ia l p la nes . M o re com p lex an d le ss w e ll kn ow n than the m orecepha lic n e trop en iton ea l coun te rp a rts , the p e lv ic fa sc ia andassoc ia te d com pa rtm en ts w e re com preh ens ive ly describ edby A uh e t a l. [5 ]. T h e ir de sc rip tions w e re b ase d on a re v iewo f p rev ious ana tom ic rep o rts , a s tudy o f a na tom ic sec tion sand cada ven ic in jec tio ns , and c lin ica l obse rva tio ns w ith C Ta nd s on og ra ph y.

A nte rio r to the pen iton eum a nd p oste rio r to the tran sve rsa lisfasc ia , the um bilic ove s ica l fasc ia sp read s in fen io rly from theum bilicus to su rroun d the u rach us , ob lite ra ted um bilic a l a rte r-

ie s , and u rin a ry b lad de r [5 ]. In a m anne r an a lo gou s to th ere na l fa sc ia , th e um b ilicoves ica l fasc ia d iv ides the a n te rio rex trape riton ea l fa t in to a pe rive s ica l space and a p re ves ica lspa ce . The pen ive sica l sp ace , con ta in ing the b lad de r, u mb ilic a la rte rie s , an d u ra chu s , is ana logo us to th e pe riren a l space .The p re ves ica l space , lo ca ted an te rio r a nd la te ra l to theum bilic oves ica l fasc ia , is ana log ous to th e an te rio r pan a ren a lspa ce . Th is huge po te n tia l com pa rtm en t ex tend s supe rio rlyu p to th e um b ilic us ; pos te rio r to the pub is it is know n as thespa ce o f R e tz ius . A t the leve l o f the b la dde r dom e , theum b ilic oves ica l fasc ia is fre quen tly seen on a x ia l C T scans asit inde n ts the con tiguo us a n te rio r p an ie ta l pe n ito neum as pa rto f the m ed ia l um bilic a l fo ld s [5 ].

A u h e t a l. [5 ] have cha rac te riz ed e x tra pe ritone a l pe lv ic flu idco lle c tions as assum in g a m o la r-too th co n fig u ra tion (F ig .1 1A ). T he c rown p o rtio n o f th e m o la r to o th lie s a n te n io n tothe u rina ry b ladd e r, b e tw een the um b ilico ves ica l fasc ia an dtran sve rsa lis fasc ia o f the a n te rio r abd om ina l w a ll, an d d is -p la ces th e b ladd e r p os te rio rly . T h e roo t po rtio n o f th e m o la rtoo th e x te nds pos te rio rly , b e tw een the fasc ia and e ith e r th epen iton eum supe rio rly o r the pan ie ta l p e lv ic fa sc ia in fe n io rly .A s the roo ts a re frequ en tly a symm e tric , th e b lad de r is o ftend isp laced aw ay from th e m id line by la rge ex trape n itone a lpe lv ic flu id co lle c t ions (F ig . 1 1 B ).

T he p reves ica l ex trape riton ea l com pa rtm en t is d irec tly co n -tinuo us w ith the in fra rena l re trope n itonea l com pa rtm en t be lowth e co ne o f ren a l fasc ia . F lu id co lle c tio ns in th is in fra ren a lsp ace freq uen tly ex te nd in to the ip s ila te ra l aspec t o f thep re ves ica l sp ace : in th is loca tion it c an be m is in te rp re te d a sbe ing w ith in the p en iton ea l po rtion o f th e pe lv is [5 ]. A d d i-tiona lly , ex trap en to nea l flu id co lle c tio ns a ris in g in the pe lv iscan ex ten d , v ia th e p reve s ica l spa ce , sup e rio rly in to there trope n ito nea l com pa rtm en ts o f th e a bdom en (F ig . 12 ). T h ep reve s ica l sp ace is a lso con tin uous w ith th e rec tus sh ea th ,the p resac ra l spa ce , and the fem o ra l she a th .

R e trope n ito nea l hem a tom a is a s ign ific an t com p lica tio n o f


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940 KORO BK IN ET AL . AJR :1 59 , N ov em be r 19 92

a va rie ty o ffem ora l vascu la r ca th e te riza tion p ro ce du res . T re r-o to la e t a l. [8 ] re ce n tly de sc ribe d th e CT find ings a nd c lin ic a ld ata in 21 pa tie nts w ith s ign if ica nt hem orrha gic com plica t ion sa fte r ca the te riz a tio n . H em a tom a was show n by C T in thefo llow ing loca tio ns : re tno pen iton eum (1 2 /2 1 ), pen ito neum (3 /2 1 ), g ro in a nd th igh (8 /2 1 ), an d abdom in a l w a ll (5 /21 ). T hed is tr ibu t ion o f h em a tom as w as exp la ine d b y e la bo ra tio n an dex trapo la t ion o f th e d is cuss ion b y A uh e t a l. [5 ] . T he fem ora lshe a th , con ta in ing the fem o ra l a rte ry and ve in , open s d irec tlyin to the p reves ica l ex trap en itone a l com pa rtm en t. B lood in th ep reve s ica l spa ce can sp rea d supe rio rly and po ste rio rly , de epto the pan ie ta l p en itone um , in to th e in fra rena l re trop erito nea lspace , and th en fu rthe r supe rio rly in to th e pe rirena l, a n te rio rp a ra re na l, pos te rio r pa ra rena l, o r ileop so as com pa rtm en ts .A lte rn a tiv e ly , b lood reach in g the p reves ica l sp ace v ia thefem ora l sh ea th ca n a lso ascend an te rio rly ju s t b enea th thetransve rsa lis fasc ia to the an te rio r ab dom ina l w all. T he re c tu sabdom in is a nd o the r ab dom ina l w a ll m usc le s can be m ored ire c tly in vo lve d ow ing to d irec t ex ten s io n o f th e b lo od , e ithe rth ro ugh the th in tran svensa lis fasc ia o r a long th e ep igas tn icvesse l shea ths pe ne tra tin g th e fasc ia . T h ese specu la tio nsassum e tha t th e e x tra pe ritone a l h em atom as in th ese pa tien tsa re a lw ays due to fem ora l vascu la r in ju ry , w h ich th en sp read sto o the r reg ion s v ia d irec t comm un ica tion . A s m ost o f the sepa tie n ts a re rece iv in g an ticoa gu lan t o r th rom bo ly t ic the rapy ,h ow eve r, one co u ld specu la te th a t a t leas t som e o f the sehem a tom as a re ind uced b y the m ed ica t ions them se lves andm igh t no t o rig ina te in th e fem o ra l she a th .

Psoas M usc leThe psoas m usc le is a frequ en t s ite o f ne tn open itonea l

a bscesse s and hem a tom as, a nd it is in tim a te ly a sso c ia tedw ith the rena l fasc ia an d th e pen ire na l and pa ra rena l sp aces .O rig ina ting from the transve rse p roce sses o f the 12 th tho rac icve rte b ra an d a ll the lum ba r ve rte b rae , th e psoa s m usc le

ex tend s in fen io rly in a p a rasp in a l lo ca t ion . Fus ing w ith theilia cu s m usc le in th e p e lv is , it then pa sses as the ile opsoa sm usc le benea th th e ingu ina l lig am en t to inse rt on the lessentrocha n te r o f th e fem ur [25 ]. B eca use its supe rio r p o rtionp asses b enea th the a rcua te ligam en t o f th e d iap h ragm , thep so as m usc le ex ten ds from th e m ed ia s tinum to the th ig h . Afasc ia l m em bra ne p ro te c ts the pso as m usc le from su rrou nd -ing d isea se : thus th e psoas m usc le is som e tim e s re fe rre d toa s a re tro fasc ia l s tru c tu re . In the u ppe r and m idd le p o rtio nso f the abdom en , the p so as m usc le m arg ina te s th e m ed ia la sp ec t o f th e fa t w ith in the pen in ena l space . It is a lso con tig -u ous , a t som e leve ls an d to a le ssen ex ten t, w ith th e po s te rio rp ara re na l sp ace .

A lth ough o ccas iona lly id iop a th ic , ab sce sses in th e psoasm usc le a re fre quen tly ca used by d ire c t sp read o f ad jacen tin fec tio n , usua lly from th e sp in e o n d is k space o r from thegas tro in tes tina l tra c t in pa tie n ts w ith d ive rtic u lit is , C n ohn sd ise ase , o r com plica ted a ppend ic it is [2 6 ]. R ena l in fec tio nsfrequ en tly ex ten d d ire c tly in to th e ad jacen t pe n in ena l spa ce ,a nd from the re th e in fe c tion can sp read d irec tly th ro ugh thep e riren a l fa t to invo lve the pso as m usc le . T he oppos ite pa th -w ay , sp read o f in fec tion from a p rim a ry ab scess in the psoasm usc le to invo lve the pen ire na l on p ananena l spaces , ra re lyo ccu rs . M os t in fec tions o f th e pso as m usc le a re n ow cau sedby p yo gen ic o rgan ism s ra the r th an by tube rcu los is [2 5 -27 ].

T he pso as m usc le is com m on ly the s ite o f a s ign ific an tre tro pe ritone a l h em atom a, esp ec ia lly in pa tien ts w ith a b lee d -in g d ia thes is o r w ho a re rece iv in g an tico agu lan t m ed ica tion s .R a re ly , a ru p tu re d abdom ina l ao rtic a neu rysm can b leedd irec tly in to the psoa s m usc le ra th e r than the p en inen a l spa ce .H em o rrh age in the a d ja cen t p en irena l o r p ana rena l com pa rt-m en ts is som e tim es a sso c ia ted w ith a hem a tom a in th e p soa smusc l e .

O n C T scans , the p rese nce o f a h em a tom a on abscess inthe pso as m usc le is usu a lly a ssoc ia ted w ith d if fu se e n la rge -m en t o f the m usc le . A n a cu te hem a tom a w ill ty p ica lly have a

F ig . 1 1 .-F lu id in p rev es ic a l s pa ce .A an d B, Sag i t t a l d iag ram (A ) o f low er ab dom en and pe lv is sh ow s um bil ico ve s ic a l fa sc ia , p reve s ica l sp ace , a nd p erives ic a l sp ace . A x ia l d iag ram (B )sh ow s la rg e flu id co llec tio n d is te nd in g an d en la rg in g p re ves ica l s pac e, p ro du cin g a c ha ra cte ris tic m ola r-to oth c on fig ura tio n. B oth d iag ram s m od ified fro m

Auh et a l. [5 ]. R = rec tum , U = u te rus , B = b lad de r, C = cecum , S = s igmo id , do tte d lin e = per i t oneum.C , CT scan show s flu id (F ) in p rev es ica l sp ace , an te rio r and la te ra l to gas-con ta in in g b la dd er (B ). Um b ilic ov es ica l fas c ia fo rm s po ste rio r and m ed ia l

m arg in s o f th es e co llec tio ns .


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F ig . 1 2 .-E xtrap er ito nea l h em ato ma asso ci-a ted w ith fem ora l va scu la r ca th eter iz a tio n an dant i c oagu la t lon .

A , C T scan show s hem atom a (H ) in le ft s ideo f p re ve sic al s pac e ab u tting an d obs cu rin g le f tfem ora l ve sse ls (v ) . F lu id (F ) Is p re sen t In retro-re cta l p re sa cra l ex ten sio n o f p re ve sic al s p a c ea lso .

B, CT scan shows tha t hem a tom a (H ) a lsoinvo lv es le f t pos te rio r p ararena l sp ace .

fo ca l reg ion o f h igh a ttenu a tion to ind ica te th e p re sen ce o ffresh b lo od , w he re as an absce ss w ill u sua lly show a cen tra llow -den s ity a rea , espec ia lly o n co n tras t-en han ced scan s . A l-thou gh uncomm on ly see n , gas b ubb les in a p soa s flu id co l-le c tion a re v irtua lly p a tho gnom on ic o f a bscess . W hen anabscess in th e pso as m usc le is caused b y d ire c t e x te ns ion o fa ren a l ab scess , the CT find ing s typ ica l o f a re na l a nd pe riren a lin flamm a to ry le s io n shou ld b e v is ib le . A ny neop lasm tha to rig ina tes in o r m e ta s ta s izes to the ne trope riton eum caninvo lve the psoa s m usc le e ithe r by b lo od -b o rne m e tas tas is o rby e x te ns ion from ad jacen t m a lign an t lym ph nodes , andoccas ion a lly such a m a lig nan t les ion , e sp ec ia lly if n ecro tic ,can be in d is tin gu isha b le on C T scans from an absce ss o r ah em a tom a in th e p soa s m usc le .

REFERENCES1 . M ey ers M A , W ha len JP , P ee lle K , Be rne A S . R ad io log ic fe a tu res o f

e xtra pe rito ne al e ffu sio ns . Rad io logy 1972 ;104 :249 - 2572 . M eyers M A . D ynam ic ra d io log y o f the ab dom en : no rm a l and p a th o lo g ic

ana tomy , 3 rd ed . N ew Y ork : Sp rin ge r-v e rla g , 19 883 . L ove L , M eyers M A , Church ill R J , R eynes C J, M on cada A , G ib so n D .

C om pu ted tom og rap hy o f e x trap e riton ea l s pac es . AJ R 1981;136 :7 81 - 78 9

4 . K nee la nd JB , Auh YH , R ub ens te in W A , e t a l. P eriren a ls paces: C T ev id en cefo r c om mun ic a tion ac ro s s th e m id lin e . Rad io logy 1987 ;164 :657 - 664

5 . Auh YH , R ub en ste in W A , Schn e id er M , ReCk le r JM , Wha l e n JP , K azam E .E xtra pe n to ne a l p a rave s ic a l s pac es : C T d eline atio n w ith U S co rre la t ion .Rad io logy 1986;159 :319 -328

6. Chesb r ough RM , B urkha rd TK , M ar tine z AJ , B urk s D D . G ero ta ve rsu sZucke r k and l : t h e r e na l f a s ci a r e vi s i te d .Rad io logy 1989 :173 :845 - 846

7. Pari enty RA, Pradel J, Picard J D, Duc ellier R, Lu brano J, Smolarski N.v is ib i l i ty and t hickening of the renal fascia on compu ted t omograms.Rad io logy 1981;139 :119 -124

8. Trerotola SO , Kuh lman JE, Fishman EK. B le e di ng c om p li ca ti on s of f emora lc a th e t er i za t io n : C T e v a lu a ti o n. Rad io logy 1990174 :37 - 40

9 . R ap t op ou lo s v , Kleinman PK , Mar ks 5, S nyder M, Silve rman P M. Renal

fas c ia l pa thw ay : p os te r io r ex ten s io n o f p an c re a tic e ffu s io ns w ith in thean te rio r p ara re na l s p ace . Rad io logy 1986:158 :367 -374

1 0. F eld be rg MAM , K oeh ler PR , van W aes PFGM . P so as com partm en t d is ea ses tu die d b y c om pu ted tom og ra phy . Rad io logy 1983 ;148 :505 - 512

1 1 . Rose n A , Ko rob k in M , S ilv e rm an PM , M oo re AV , D u nn ic k NR . C T d iag no s iso f ru p tu re d ab dom ina l ao rtic a ne u ry sm . AJ R 1984 :143 :265 - 268

12 . H o pp e r K D , S he rm an JL , G hae d N . Ao rtic ru p tu re in to re trope ritone um( let ter ) . Ai R 1985 :145 :435 - 437

1 3 . V ibh ak a r SD , L ee H , P e trus ch ak M , Be llo n EM . Ao rtic an eu ry sm p res en tin ga s p so as e nla rg em e nt. J Com pu t A ss is t T om og r 1981:5 : 925 -928

1 4 . Fe ldb erg M AM . C om puted tom og rap hy o f th e re tro pe ritoneum : an an atom -ic a l an d pa tho log ic a l a t las w ith em phas is o n the fa s c ia l p lan es . B os ton :M a rtin us N ho ff, 1 98 3 :55

1 5. K un in M . B rid g in g s ep ta o f the pe rin eph ric s pa ce : an a tom ic , pa tho log ic ,a nd d ia gn os tic c on sid era tio ns . Rad io logy 1986;158 :361 -365

16 . M cC len nan B L , L ee JK T , Pe te rs o n R R . A na tom y o f th e pen re na l a re a .Rad io logy 1986 :158 :555 - 557

17 . R ap top ou los V , C umm in gs T , Sm ith E H . C om pu te d tom ogra ph y o f life -th rea ten ing com plic a tio ns o f abd om in a l a o rt ic a ne u ry sm : the d is rup tedaor t ic wal l . In ve st R ad io l 1987 :22 :372 - 376

18 . B osn ia k M A . S po n ta ne ou s sub ca ps u la r an d pe rirena l h em a tom a s (ed ito -r ia l) . Rad io logy 1989:172 :601 -60219 . B e lv ille J S , M orge n ta le r A , Lou gh lin KR , T um eh 5 5 . Sp on tan eo us pe ri-

nephr ic an d s ub ca psu la r re na l h em orrha ge : e va lua tio n w ith CT , US , andang iog r aphy . Rad io logy 1989:172 :733 -738

20 . H ea ly M E , T on g 5 5 . M os s AA . U rin ite rou s p se udo c y s t: c om pu ted to n ic -g ra ph ic f in din gs . Rad io logy 1984 :153 :757 - 762

21 . M eyers M A. l.k in if ero us p erir en al p se ud oc ys t: n ew o b s er v at io n s . Rad io logy1975:117:539-545

22 . F ned enbe rg RM , M oo reh ou se H , G ade M . Ifrm n om as sec on da ry to pye lo -s in us b ac kf lo w. U ro l R ad io l 1983 ;5 :23 - 29

23 . D od ds W J , D a rw ees h AM A , Law s on TL , e t a l. Th e re trop e riton ea l s p ace srev is ited. A iR 1986:147 :1155-1161

24 . R ub en ste in W A, W halen JP . E xtrape riton ea l s paces ( c ommen ta r y ) . Ai R1 9 86 ; 14 7 :1 1 6 2- 1 16 4

25 . J e ffre y R B , C a lle n PW , F ed e rle M P . C om pu te d tom ogra ph y o f pso asabs ces ses . J Com pu t A ss is t Tom ogr 1990 :4 :639 - 641

26 . M ende z G , Is iko ff MB , H il l M C. Re tro pe ritonea l p roc esses in vo lv ing th ep so as d em o ns tr ate d by c om pu te d to mo gra ph y. J Com pu t Ass is t T om og r1980 ;4 :78 - 82

2 7. R al ls P W, Bo sw ell W , H en de rs o n A, R ogers W , Bo ge r D , Halls J. CT ofin flamm ato ry d is e as e o f th e pso as m usc le . Ai R 1980 ;134 :767 - 770


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Book R ev iew

Bas ic D opp le r P hys ic s . B y H ans -J# {2 48 }rg en Sm ith an d Jam es A . Zagzebsk i. M ad iso n , W I: M ed ica l P hys ic s P ub lis h ing ,12 1 pp ., 199 1 . $ 39

Th is book is in te nd ed fo r re s id en ts , ra d io log is ts , an d s on og rap he rsw ho a re fam ilia r w ith B -m ode so no g raph y bu t h av e litt le o r noknow ledge o f D opp le r phy s ic s , o r phys ic s in gene ra l. It is d iv id ed in totw o m ajo r s ec tio ns : b as ic Dopp ler ph ys ics and co lo r f low im ag ing .Tw e lv e o f th e 17 chap te rs dea l w ith ba s ic D op p le r ph y s ic s . E ac h o fthe cha p te rs is b rie f an d d ea ls w ith a s ing le ba s ic c on cep t. Th e bookp rog re s ses chap te r b y chap te r from firs t p r in c ip le s to m ore com pli-ca ted e xp lan a tions o f D op p le r ph y s ic s , s ig na l p ro ce s s ing , a nd sp ec -tra l a na ly s is . N um e rou s d ia g ram s he lp c la rify s u ch ph enom ena a sa lia s in g a nd the fac to rs tha t d ic ta te pu ls e re pe titio n fre qu en c y . Ause fu l d iscu s s ion o f m ethods to p re ven t a lia s in g is in c lu ded . C hap te r6 con ta ins a b rie f bu t com p rehens iv e d iscu ss ion o f D opp le r s ig na lp rocess ing .

C hap te rs 9 , 1 0 , and 1 1 d iscus s S hannon s sam p lin g theory andh ow it re la te s to the ph en om enon o f D op p le r a lias ing . C h ap te r 12dea ls w ith the te chn iques and sou rce s o f e rro r in he ren t in vo lum etr icb lo od -flo w c alc ula tio ns .

Th e s ec ond se c tio n , w h ic h d ea ls w ith c o lo r flow im ag ing , be g in sw ith an in trodu c t ion to the ins trum en ta tio n o f B -m ode g ray -s c a le rea l-tim e im ag ing . D iffe ren t t ran sd uce r an d s ig na l-p roc es s in g c on fig u ra -t io n s a re d iag ram ed , and the bas ic w o rk in g p r in c ip le s a re exp la in ed .Scann ing speed a nd fra me ra te lim ita tio ns a re d esc rib ed . T he co nce pto f d ynam ic fo cus ing is p re sen ted w ith he lp fu l d ia g ram s. C o lo r flowa lia sin g is p re se nte d in C hap te r 16 . A ll co lo r flow im ages in th isd iscu ss ion w e re ob ta in ed by us ing a Dopp le r phan tom . T he fin a lch ap te r d ea ls w ith th e fa irly rec e n t c on ce p t o f tim e -dom a in co rre la t ionas a m ethod o f e s tim atin g b lood -flow ve lo c ity . T h is p ro ces s , w h ich isa va r ia tio n o f th e tec h n iq ue s u sed in c o lo r v e lo c ity im ag ing , ha srecently been in tro duc ed in a comm erc ia lly a va i lab le u n it . T h is tec h -n iqu e u ses a n ana ly s is o f m u ltip le ec ho es tran sm itted a t v e ry s h o rt

in te rva ls . T he pa tte rn o f re fle c to rs ob ta in ed from re tu rn in g pu lse s issu b je c te d to a t im e -d om a in c o rre la tion m e th od , w h ic h is use d toex tra c t a tim e change tha t bes t m a tches echo s igna tu re s fromse qu en t ia l p u ls es . Th e tim e ch an ge is c o rre la ted w ith the D opp le rpu lse ra te in orde r to ob ta in an es tim atio n o f b lo od -flow ve lo c ity . T hepo ten t ia l advan tages o f tim e-dom ain ve lo c ity e s tim atio ns in c lu deim p ro ve d c o lo r D op p le r res o lu t ion an d d ec rea se d o r a bs en t a lias ing .O the r po ten tia l a dva nta ge s in clud e lo w e r pow er ou tpu t a nd thepo ten tia l fo r rea l-tim e vo lum e tric flow es t im a tio ns .

A lthough the des ign and con ten t o f th is tex t m ake i t a p ote ntia llyus e fu l tex t fo r b eg inn e rs , the e n tire m anus c rip t is filled w ith m is s pe ll-in g s , in co rre c t te rm ino log y , and in co rre c t s ta tem en ts . A fte r I h ad readth is m anuscrip t w ith som e conce rn and d ism ay ove r th e appa ren tla ck o f p roo fread ing tha t re su lte d in the se in co r rec t an d m is le ad ings ta tem en ts , a tw o-page e rra ta s ta tem en t a rr ived from the pub lishe r.T he pub lishe r has s ta ted tha t it in te nds to append th is e rra ta shee tto the fron t o f th e te x t. I f in d th is qu ite d is tu rb in g and th in k it is u nfa irto a sk a reade r to re fe r to an e rra ta shee t m o re than 50 tim es dur in gthe read ing o f a te x t th a t is on ly 1 21 pages long . F u rth e rm o re , abeg inn ing s tuden t o f D opp le r phys ics m igh t no t re cogn iz e an in co rre c ts ta tem en t and the re fo re w ou ld no t au tom atic a lly k now to re fe r to thee rra ta shee ts . C onsequen tly , th e po ten tia l reade r w ou ld be fo rced tota ke the e rra ta shee t and go th rough the book co rrec tin g m is ta ke s.T h is is unaccep tab le . T he au tho rs and pub lishe r s hou ld com bine the ire ffo rts to co rre c t a ll the se obv iou s e rro rs and com e up w ith a secondedit ion.

Ba rb a ra A . C arro l lD uke U nive rs ity

D urham , N C 27710


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944 G RANT ET AL . AJR :i59 , N o vem be r 1 99 2

the p rop e r hep a tic a rte ry w ith the po rta l ve in and comm onb ile duc t in to the po rta hepa tis . In m os t ca ses , th e hepa tica rte ry lie s an te rom ed ia l to the po rta l ve in . A lm o st 50% o fp a tien ts , how eve r, h ave som e fo rm o f ana tom ic va ria tion o rabe rran t o rig in o f th e hepa tic a rte ry . A b e rran t he pa tic a rte rie styp ica lly take one o f tw o fo rm s: a ccesso ry o r re p la ced . Th efo rm e r im p lies the p re se nce o f an ex tra h epa tic a rte ry ,w he reas th e la tte r is m e re ly a subs titu te fo r th e no rm a lvesse l. O f the tw o , re p la ced a rte ries a re m ore comm on , andin b o th case s , the a nom a lo us o rig in van es , d epend ing o nw he the r the righ t o r le ft hepa tic a rte ry is a ffec ted . O n therigh t, th e supe rio r m esen te ric a rte ry m ost com m on ly g ivesris e to the a be rra n t a rte ry ; on the le ft, the a rte ry a lm os ta lw a ys a rises from the le ft ga s tr ic a rte ry . A be rran t hep a tica rte ries o ften lie do rsa l to the po rta l ve in [2 ].

T he ex tra hepa tic po rt ion s o f the hepa tic a rte ry a re o fte nbe s t v isua liz ed by de tec ting th e ce lia c ax is an te rio r to theao rta an d fo llow in g the b ra nch tha t ru ns to th e righ t. I f thea rte ry is lo ca ted benea th the po rta l ve in , a n abe rran t o rig inshou ld be cons ide red . In the po rta he pa tis , the com m onhepa tic a rte ry is ea s ily v isu a lized in m ost ca ses an te rio r tothe p o rta l ve in when scann in g is don e from an ob lique in te r-cos ta l a pp roa ch . W ith in the liv e r, the b ran ch es o f the hepa tica rte ry fo llow the ir a tte ndan t po rta l ve ins a nd a re v is ib le w e llin to the p e riph e ry if the co lo r D opp le r techn iqu e is op tim ized .T he hepa tic a rte ry can be d is t ing u ished from the ad jace n tve in b y its pu ls a tili ty , h ig he r ve lo c ity (o fte n d is p la yed in ad iffe ren t sh ade o f co lo r), and sm a lle r s ize . S pe c tra l a na lys isa llow s ab so lu te d is tin c tion be tw een a rte ry and ve in and w illc on firm pa te ncy o f th e hepa tic a rte ry .

T he hepa tic a rte ry p la ys a ro le su bo rd ina te to th a t o f th epo rta l ve in in p a ren ch ym a l oxyg ena tion . The po rta l ve in su p -p lie s 70 -75% o f in com ing b lood [3 ]. T h is dua l b loo d supp lym ake s hepa tic in fa rc tion ra re in th e na tiv e live r. T he o xygencon ten t o f po rta l ven ous b lood is usua lly su ff ic ien t to a llowno rm a l he pa tic func tio n even in the even t o f com p le te h epa tica rte ry th rom bo s is . A b no rm a litie s o f th e h epa tic a rte ries a rera re ly a cause o f liv e r d isea se . E n la rgem en t o f the hepa tica rte ry , in c rea sed flow , an d a to rtuous co rkscrew a ppea r-an ce a re comm on ly obse rved in pa tien ts w ith c irrhos is a ndpo rta l hype rtens ion [4 ], b u t in c reased vascu la r res is ta nce (a sshow n by an incre ase d res is tive o r p u lsa tility in dex ) ha s n o tbeen a use fu l d ia gno s tic ind ica to r. B ecause o f inc reaseddependen ce on th e a rte ria l sy s tem fo r oxygena tion whenpo rta l hype rtens ion o ccu rs , th e hepa tic a rte ry m ay be de -te c te d w ith co lo r D opp le r im ag ing m o re e as ily than th e po rta lve in is . T h is s itua t ion ca n be pa rtic u la rly tro ub lesom e inpo ten tia l liv e r tran sp lan t rec ip ien ts in w hom th e pa ten cy o fth e p o rta l ve in m ust be es tab lish ed . In add ition , w ith rea l-tim esonog raph y , ec ta t ic h epa tic a rte ries in p a tie n ts w ith c irrho s ism ay be d iffic u lt to d is t ing u ish from d ila ted in tra hepa tic b il ia ryrad ic les [5 ]. T h is p rob lem is e as ily so lved b y us ing co lo r o rdup lex Dopp le r im ag ing , as b ile d uc ts p ro duce no D opp le rs ig na l [6 ] (F ig . 1 ). T he d iffe ren t ia tion b e tw een vascu la r s tru c-tu res and d ila ted b ile duc ts m ay a lso be o f va lue whend ra inage o f a n obs truc tiv e b ilia ry s ys tem is cons id e red a s aposs ib le trea tm en t. C o lo r D opp le r im ag ing can be used tod ire c t the need le to a d ila ted duc t and avo id pun c tu re o f thea dja ce nt v es se l.

C o lo r D opp le r im ag in g has been used to inve s tiga te a rte ria lflow pa tte rns in a nd a round hepa tic m asse s in an e ffo rt toim p rove the spec ific ity o f the sonognaph ic exam in a tion . Th eflow o f hem ang iom as re po rte d ly is too s low to p ro duce aDopp le r sh ift, a nd the re fo re th ey typ ica lly app ea r avascu la r.U n fo rtu na te ly , m e ta s ta se s m ay a lso be a vascu la r, and thetw o canno t b e d iffe re n tia ted [7 ]. T ay lo r e t a l. [7 ] have repo rtedpea k sys to lic D opp le r sh ifts g re a te r tha n 5 kH z a s be ingsp ec ific to hepa to ce llu la r ca rc inom a (HCC ). Tana ka e t a l. [8 ],w ho u sed co lo r D opp le r im ag in g , sug ges ted a baske t pa t-te rn w as a lso typ ica l o f H CC . M ann e t a l. [9 ], h ow eve r,repo rted h igh -ve loc ity flow in c irrh o tic live rs w ith ou t hep a to -m as and a ttr ib u ted such flow pa tte rns to the p rese nce o fsm a ll a rte rio ve nou s m a lfo rm a tion s ra th e r than to tum or. R e -ce n t w o rk suggests tha t co lo r D opp le r p a tte rns a re p roba b lyo f lit tle va lu e in d iffe ren t ia ting va rio us h epa tic les ions . R a Ils[1 0 ] has shown tha t hem ang iom as m ay ha ve in te rn a l va scu -la rity (p ro bab ly the resu lt o f im p rovem en ts in D opp le r sen s i-t iv ity ) and tha t th e pa tte rn s descr ib ed by T anaka e t a l. [8 ] a sspec ific fo r H CC a re comm on ly seen in m e ta s ta ses . A lth ougho f m in im a l va lue a s a d iagn os t ic too l in h epa tic m asses , co lo rD opp le r im ag in g can be used to loca liz e a re as o f s ig n ifican tvascu lan ty if conce rn ex is ts abou t th e op tim um s ite fo r b io p sy .

The sp len ic an d hepa tic a rte ries a re the m ost com m on s itesfo r p seu doaneu rysm s in the abdom in a l ve sse ls . T hese ab -n o rm alit ie s typ ica lly occu r in a ssoc ia tio n w ith traum a o r p an -c rea titis an d m ay appea r as a com p lex o r c ys tic m ass onro u tine nea l-tim e e xam ina tio n [1 1 ]. W hen la rg e, pseud oan eu -rysm s m ay m im ic an absce ss and pe rcu tan eou s p unc tu re o rd ra inag e m ay be cons ide re d . In o rd e r to a vo id po ten tia lca tas troph e , co lo n o r dup lex im ag ing shou ld be pe rfo rm edwhene ve r a p seudoaneu rysm is e ven rem o te ly con s id e red asp a rt o f the d iffe ren tia l d ia gnos is . U nless a pseudoaneu rysmis th rom bosed com p le te ly , th e D opp le r c ha ra c te r is tics a resu ff ic ien tly spec ific th a t a de fin itive d iag nos is ca n be m ade .

The Porta l V enous Sys temThe po rta l ve in and its m a jo r b ranches ca n be ea s ily v isu -

a liz ed in a ll p a tie n ts b y us ing a n igh t lo ng itu d in a l in te rc o s ta lapp ro ach s im ila r to th a t use d to d isp lay the com m on hepa ticd uc t. W hen th is ap p roa ch is used , no rm a l flow in th e m a inp o rta l ve in is inva ria b ly d ire c te d tow a rd th e tran sd uce r a ndd isp la yed in red (a ssum ing a red tow a rd and b lue aw ay co lonsch em e ). F low in th e pos te rio r b ra nch o f th e n igh t po rta l ve in ,h ow eve r, is aw ay from the tra nsduce r an d sh ou ld n o t becon fu sed w ith tha t o f th e nea rb y hepa tic ve in s (a ls o typ ic a llyd isp la yed in b lu e ). I f a qu es t ion ex is ts , the ve sse l can befo llow ed to its o rig in o r eva lua ted w ith spe c tra l D opp le r im -ag i ng .

M an y s ign ific an t abn o rm a litie s o f th e p o rta l veno us sys temare read ily cha ra c te rize d by us ing dup lex and co lon D opp le rim ag ing . A na tom ic ab no rm a litie s a re re la tive ly un usua l, bu td up lic a tio n , an anom a lou s co u rse , a nd aneu rysm s have beendesc rib ed [1 2 , 1 3 ] (F ig . 2 ). In add itio n , fis tu la s m ay a ffe c t th epo rta l venou s sys tem and invo lve e ithe r th e h epa tic a rte ry o rth e hepa tic ve in s . In bo th ca ses , fis tu lous les io ns m ay becongen ita l o r acqu ire d . C om mun ica tions b e tw een th e hepa tic


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F ig . 2 .- Sa g it ta l c olo r D op ple r im age o f apa t i e n t with en d-s tag e liv er d ise ase an d d oc-um en ted po rta l h ypertens ion show s a porta lv ei n a ne ur ys m (ar rows) e xt en di n g o ff p os te ri orma in po r ta l v ei n ( P) . To -a n d- fr o f lo w p atte rnI s s i m i l a r to th at s een in pse ud oa ne u ry sm s andi nd ic at es a v as cu la r c ul -d e -s ac .

A JR :1 5 9, N ov em b er1 99 2 CO LOR DOPPLER IM AG ING O F HEPAT IC VASCU LATURE 945

F ig . 1 .-B il ia ry d ila ta tio n . R ea l- tim e scann ings ho wed n um ero us p ara lle l, tu bu la r an ec ho ic s tru c-tu res in liv e r . Ea riy b ilia ry d ila ta tio n w as su s-p ec ted , b u t en la rge d he pa tic a rte rie s i n t h is pa t ien tw ith c irrho s is w ere a lso a cons id era tio n . Co lo rD opp le r im age th rough one o f th ese a re as show sn o flo w in o ne tu bu lar s tru ctu re , c on firm in g b ilia rydilatat ion. N o te o b vio u s flow In ad jac en t p o rta l v e in( arrow) . C olo r D opp le r im ag in g a llo ws de fin itived iffe ren tia tion be tw een d ila te d d uc ts a nd a dja ce ntvesse ls .

a rte ry and the po rta l ve in ten d to be sym p tom a tic ; be ca useo f th e h igh p re s su re in the a rte ry , la rge quan titie s o f b lo odcan be de liv e red to the p o rta l s ys tem , caus ing se ve re po rta lhype rte n s ion . M os t hepa tic ve in /po rta l ve in fis tu la s , on theo the r ha nd , a re asym p tom a tic un le ss the y a re la rge enoughto d ive rt the m a jo rity o f p o rta l flow and cau se hepa tic ische -m ia . P a tien ts w ith th is typ e o f fis tu la occas ion a lly ha ve en -cepha lop a th y o r h ypog ly cem ia [14 ].

F ind ing s on co lo r D opp le r im ag ing shou ld be de fin itive inbo th va rie tie s o f f is tu la s. In pa t ien ts w ith he pa tic a rte ry /po rta lve in comm un ica tio n s , m a rked ly d ila te d po rta l v enous s tru c -tu nes w ith a bundan t fo rm a tion o f co lla te ra ls a re typ ica l [15 ](F ig . 3 ). P o rta l ve in flow is o fte n reve rsed and a rte ria liz ed .T u rbu len t, h ig h -ve lo c ity , low -re s is ta n ce a rte ria l flow w ith aco lo r D opp le r b ru it (ra ndom co lo r ass ignm en t ou ts ide there g ion o f an ac tua l ve s se l) m ay be p re sen t [1 6 ]. A lth ough ause fu l d ia gnos tic s ig n , a co lo r D opp le r b ru it m ay obscu re thevascu la r a na tom y o f th e fis tu la and can be m in im ize d b yin crea s ing the ve lo c ity sca le o r w all fi lte r. P o rta l ve in /he pa ticve in fis tu las te nd to be less sym p tom atic than a rte ria l le s io ns ,as flow p roceed s from one low -p ressu re sys tem to ano th e r.R e la tiv e ly la rge cys tic spaces m ay be seen in the live r in thea rea o f the com m un ica tio n . C o lo r D opp le r im ag ing can beused to m ake the d iagnos is b y de te c ting flow in the se spaces .W ith co lo r D opp le r im ag in g , it s hou ld a lso be po ss ib le tod e fin e th e a tten dan t vascu la r co nnec tio ns [14 ] (F ig . 4 ).

T he po rta l veno us sys tem is an iso la ted va scu la r un it w ithre la tive ly m onophas ic flow . S pe ctra l a na lys is w ill s how on lym ino r flu c tu a tio ns a ssoc ia ted w ith ca rd iac o r resp ira to ry m o-t io n . In cases o f hepa tic ve in /po rta l ve in fis tu la s , th e comm u -n ica tio n be tw een the s ys tem ic and po rta l venous s ys tem s

F ig . 3 .-H e pa tic a r te ry /p o rta l ve in fis tu la in ap a tie n t w ith kn ow n fis tu la an d m ultip le p re v io ushe pa tic a rte ry em bo liz a tio ns . A t tim e o f im ag ing ,p a tie n t h ad rec u rren ce o f p orta l h yp er ten sio n.T ran svers e co lo r D opp ler im age th ro ugh po r t s he-p atis sh ow s area o f h ig h-v elo city , t u r bu len t f low(s tr aig ht a rr ow ) In a n a rte ry ly ing po ste rio r to p orta lv e in . N o te re ve rsa l o f flow In po rta l v e in (cu rvedarrow) . S upe rio r m esen ter ic ar te rio g ram con -firm ed p re se nc e o f he pa tic a rte ry /po rta l v e in f is -tu la a ris in g fro m co lla te ra ls o rig in atin g fro m g as-t ro d uo d en a l a rt er y.

o ften a llow s the trip has ic spec tra l p a tte rn o f th e hepa tic ve in sto be re fle c ted back in to the po rta l v e in , p roduc ing a pa tte rno f po rta l ve in pu lsa til ity . S uch pu lsa til ity is bes t cha ra c te rizedb y us ing sp ec tra l D opp le r im ag ing bu t m ay be ev ide n t on theco lo r exa min ation be ca use o f its a lte rna tin g red /b lu e pa tte rn .Occas io na lly , h ow eve r, p u lsa tile flow m ay be de tec ted in anappa ren t ly no rm al p o rta l ve in . S om e deg re e o f po rta l pu lsa til-ity is o fte n obse rved in con tro l sub je c ts (no hepa tic abno r-m a lities ), b u t th e recen t s tud y by D ue r in c kx e t a l. [1 7 ] show edtha t a g rea te r th an tw o -th ird s change be tw een peak andm in im a l ve loc ity sh ou ld be v iew ed w ith su sp ic ion . A s p rev i-ou s ly d is cusse d , any ana tom ic comm un ica tion be tw een th esys tem ic and po rta l ve in s , in c lud ing su rg ica lly c rea ted po rta -ca va l shun ts o r he pa tic ve in /po rta l ve in fis tu la s , m ay lead toa pu lsa tile po rta l ve in . M o re com m on ly , howe ve r, c lin ica llyre leva n t po rta l ve in p u lsa tility is asso c ia ted w ith rig h t-s idedhea rt fa ilu re (inc reased righ t a tr ia l p re ssu re ) a nd /o r tr icusp idre gu rg ita tion [1 7 , 1 8]. In su ch cases , pa tie n ts w ho have noh is to ry o f h ea rt d ise ase shou ld be re fe rred fo r a ca rd iaceva lu a tio n tha t in c lude s a de ta iled echo ca rd iog ram w ith spe -c ific a tte n tio n to the tr icu sp id va lue .

P o rta l ve in th rom bos is (PVT ) is a ssoc ia ted w ith neop la s ia(H CC in pa rt icu la r), hype rcoagu la b le s ta tes , use o f o ra l con -tra cep tiv es , and b ilia ry a tres ia . M any cases occu r w ith noappa re n t und e rly ing abno rm a lity . T he s igns and sym p tom s o fPVT a re re la tive ly nonspe c if ic a nd inc lud e the on se t o r w ons-en ing o f a sc ites an d abdom in a l pa in o r d is te ns ion . H epa to -m ega ly is no t typ ica l, a nd a lte ra tions in th e resu lts o f liv e rfu n c tio n te s ts a re no t d ia gnos tic . C o lo r D opp le r sonog raphyis u se fu l in th e d iagnos is o f PVT [19 ]. T he h igh n ega tivep red ic tive va lue (0 .98 ) s ugges ts tha t in pa tien ts suspec ted o f

tc, espacion extra peritoneal , normaly colecciones liquidas

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