Congenital heart defects involving an Anomalous Origin of the

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1 Dign Interv Rdiol 2012; 18: Turkish Soiety of Rdiology 2012 CARDIOVASCULAR IMAGING CASE REPORT Progressive intr-individul rdition dose redution during CT surveillne of ptient with ALCAPA syndrome Mthis Meyer, U. Joseph Shoepf, Christin Fink, Anthony M. Hlvek, Thoms Henzler ABSTRACT We present the se of young ptient with Anomlous Origin of the Left Coronry Artery from the Pulmonry Artery ( ALCAPA) syndrome who underwent reonstrutive surgery nd multiple rdi omputed tomogrphy ngiogrphy (CTA) studies for pre-surgil evlution nd follow-up. Throughout ptient s linil ourse, progressive implementtion of rdition dose-sving tehniques signifintly lowered the rdition dose y 95%. This se highlights the pilities of developing rdition protetion strtegies tht drstilly lower rdition exposure during CTA. Key words: oronry rtery pulmonry rtery X-ry omputed tomogrphy rdition dosge reonstrutive surgil proedures From the Divisions of Hert nd Vsulr Center (M.A., U.J.S. shoepf@mus.de, T.H.), nd Peditri Crdiology (A.M.H.), Medil University of South Crolin, Chrleston, South Crolin, USA; the Institute of Clinil Rdiology nd Nuler Mediine (C.F.), Heidelerg University, Medil Fulty Mnnheim, Mnnheim, Germny. Reeived 18 Deemer 2011; revision requested 12 Jnury 2012; revision reeived 6 Mrh 2012; epted 9 Mrh Pulished online 13 June 2012 DOI / DIR Congenitl hert defets involving n Anomlous Origin of the Left Coronry Artery from the Pulmonry Artery (ALCAPA) re rre ut hve serious linil implitions. ALCAPA syndrome, whih ws first desried in 1866 nd is lso known s the Blnd-White- Grlnd syndrome, is estimted to our in one of every live irths, representing etween 0.24% nd 0.46% of ll ongenitl rdi nomlies (1). Speifi omputed tomogrphy (CT) findings of this disese efore nd fter reonstrutive surgery hve een investigted (2, 3). We desried the se of young ptient with ALCAPA syndrome, efore nd fter reonstrutive surgery, tht highlights the pilities of developing rdition protetion strtegies tht drstilly lower rdition exposure during rdi CT ngiogrphy (CTA). Cse report An 18-yer-old womn with ALCAPA syndrome who hd undergone prior surgil re-implnttion of her nomlous left oronry rtery (LCA) into the orti root ws referred to us for CTA due to the suspeted stenosis of her nstomosis. She hd een dignosed with ALCAPA t the ge of 17 fter two-yer history of intermittent hest pin. Throughout the ptient s linil ourse of five months, her medin ody mss index (BMI) ws 22.0 kg/m 2 (rnge, kg/m 2 ). The initil dignosis hd een onfirmed y CTA study (Fig. 1) performed t n outside institution; this CTA ws performed on dulsoure CT (DSCT) snner (Somtom Definition, Siemens Helthre, Forhheim, Germny) using routine dult retrospetively ECG-gted quisition protool with mm detetor ollimtion, 330 ms gntry rottion time, nd 120 kv tue voltge for oth tues with n effetive tue urrent-time produt of 834 mas eff. These prmeters resulted in n effetive rdition dose (ED) of 14.1 msv sed on hestspeifi onversion oeffiient ( =0.014 msv Gy -1 m -1 ). No pre-medition ws neessry s the ptient hd hert rte of 61 ets per min (pm). The ptient ws referred to our hospitl for surgil orretion three months fter the initil dignosis. The norml left min oronry rtery ws exised on utton of pulmonry rtery tissue nd re-implnted in the sending ort ove the orti vlve. A postopertive ehordiogrm showed turulene suspiious for stenosis in the re of nstomosis nd wll-motion normlities suggesting myordil infrtion. For further evlution of these findings (inluding rdi funtion), we hose prospetively ECG-triggered dul-pulse CTA protool on seond-genertion DSCT snner (Somtom Definition Flsh, Siemens Helthre). With this tehnique, short, full-nominl tue urrent X-ry pulse ws pplied during predefined 547

2 d Figure 1. d. Retrospetively ECG-gted CTA t 120 kv of n 18-yer-old womn with intermittent hest pin. Three-dimensionl volume rendering (, ), mximum intensity projetions (), nd urved multiplnr reonstrutions (d) show n nomlous origin of the left min oronry rtery from the pulmonry rtery (white rrows). The effetive rdition dose of this study ws 14.1 msv. Ao, ort; Cx, irumflex oronry rtery; LAD, left nterior desending oronry rtery; PA, pulmonry rtery; RCA, right oronry rtery. phse of the rdi yle (75% RR in this ptient) while onurrent X-ry emission window t 20% of the nominl tue urrent overed the mjority of the rdi yle (30% 90% RR in this ptient). This tehnique dereses the totl rdition dose while llowing evlution of the left ventriulr funtion y inlusion of end-systoli nd end-distoli rdi phses. Aquisition prmeters were individully dpted to mm detetor ollimtion, 280 ms gntry rottion time, 100 kv tue voltge, nd 320 mas urrent-time produt. This tehnique, t 100 kv, resulted in n ED of 2.8 msv, whih represents rdition dose redution of ~80% ompred with the initil, routine protool. Agin no pre-medition ws neessry, s the ptient hd hert rte of 65 pm. This CTA study (Fig. 2) reveled right-dominnt oronry rtery system with the right oronry rtery (RCA) ppering lrge nd tortuous throughout its ourse. Severl oronry rtery fistule were present (Fig. 3) etween the RCA nd the right ventrile, s well s the LCA nd the left ventrile. A non-ostrutive reltive mismth in size etween the new orti ostium of the LCA nd the reminder of the vessel ws seen. On funtionl ine evlution, there ws evidene of hroni pil left ventriulr infrtion with hypokinesis of the ffeted segments nd mild mitrl vlve prolpse. Two months lter, the ptient experiened severl episodes of hest pin during exertion. The findings of the flow disturnes from ehordiogrphy were gin onerning for post-surgil omplitions t the nstomosis site. Evlution with oronry theter ngiogrphy ws onsidered, ut ultimtely, repet of CTA ws onsidered preferle. Beuse no funtionl ssessment ws deemed neessry t the time, we hose highpith, prospetively ECG-triggered spirl quisition protool (Fig. 4). Agin, no pre-medition ws neessry s the ptient hd hert rte of 85 pm. The following individulized prmeters were seleted: 280 ms gntry rottion time, mm detetor ollimtion, nd 370 mas effetive tue urrent t 100 kv tue voltge. Bsed on the ECG signl, the elertion of the tle nd initition of dt olletion were triggered to over the hert in the lte distoli phse. The pith of 3.4 (tle feed, 46 m/s) inherent to 548 Novemer Deemer 2012 Dignosti nd Interventionl Rdiology Meyer et l.

3 Figure 2.. Prospetively ECG-triggered dulpulse CTA study t 100 kv. Volume-rendered disply (, ) shows the sme ptient one month fter reimplnttion surgery; the origin of the left oronry rtery now rises from the orti root. Curved multiplnr reformtion () shows the reltive mismth in size etween the new orti ostium of the left oronry rtery nd the reminder of the vessel (white rrow). The effetive rdition dose of this study ws 2.8 msv, whih represents rdition dose redution of ~80% ompred with the initil CTA. Ao, ort; Cx, irumflex oronry rtery; LAD, left nterior desending oronry rtery; PA, pulmonry rtery; RCA, right oronry rtery. this sn mode voided overlpping rdition nd sustntilly redued the rdition dose to the ptient. This high-pith spirl quisition protool resulted in n ED of 0.7 msv, representing dose redution of 95% ompred with the ptient s first retrospetively ECG-gted protool t 120 kv nd redution of 75% ompred with the seond prospetively ECG-triggered dul-pulse CTA study. The study gin reveled the previously oserved size mismth etween the lier of the LCA t the ostium nd the reminder of the vessel; however, there ws no evidene of stenosis or other omplitions. The RCA ws lso dilted, nd extensive ollterl vessels were seen, whih were ssoited with oth the left nd right systems. Disussion This se illustrtes oth the dilemm nd emerging mitigtion strtegies onerning repet dignosti testing nd umultive rdition exposure in young ptients. While the dditive Figure 3. Axil retrospetively ECG-gted CTA imge t 120 kv shows multiple fistuls rossing through the interventriulr septum into the right ventrile. Volume 18 Issue 6 Progressive intr-individul rdition dose redution during CT surveillne of ptient with ALCAPA syndrome 549

4 Figure 4.. Prospetively ECG-triggered high-pith spirl CTA quisition t 100 kv two months fter the seond study. Curved multiplnr reformtions () nd volumerendered reonstrutions (, ) show similr imge qulity ompred to the first nd seond studies despite 95% nd 75% rdition dose redution, respetively. Ao, ort; Cx, irumflex oronry rtery; LAD, left nterior desending oronry rtery; RCA, right oronry rtery. rdition effets of seril follow-up exmintions re prolemti, suh tests re often n unvoidle linil relity in the ontext of surgil repir of omplex hert disese, espeilly if symptoms re onerning the post-surgil omplitions. However, if CT is deemed neessry, our se lso demonstrtes tht the ongoing evolution of CT tehnology, when omined with reful, individulized dpttion of CT protools to oth the ptient nd linil senrio, llows sustntil redution in rdition exposure without detriment to the dignosti yield. Hemodynmi onsequenes of ALCAPA pper in the neontl period, when the pulmonry pressure flls elow the systemi pressure, nd the dutus rteriosus loses. Blood from the high-pressure RCA territory fills the LCA vi extensive ollterls nd trvels in retrogrde diretion to exit into the min pulmonry rtery. Ptients who do not develop signifint interoronry ollterls soon fter irth re onsidered to hve infntile type ALCAPA, nd they present with filure to thrive during the first three months of life; these ptients my go on to develop myordil ishemi, left ventriulr dysfuntion, nd/ or mitrl insuffiieny. Left untreted, 90% of these hildren die in the first yer of life (4). The dult-type ALCAPA is omprtively rre nd represents the 10% 15% of survivors who hve well-estlished interoronry ollterls nd often no overt myordil ishemi (5). Unfortuntely, mlignnt rrhythmis re ommon, nd 90% of suh ptients die suddenly, t men ge of 35 yers (4, 5). Our ptient hd no symptoms until the ge of 15 yers, when she strted experiening intermittent hest pin. Trditionlly, invsive oronry theteriztion is used for definitive dignosis nd surveillne following surgil repir of this disorder. As demonstrted in our se nd onfirmed y other studies, the emergene nd ongoing refinements of CTA inresingly enle replement of invsive testing with non-invsive, omprehensive CT ssessment of rdi morphology nd funtion, whih rguly hs greter effiy thn oronry theteriztion for demonstrting the ostil origin nd proximl ourse of nomlous oronry rteries (2, 3, 6). A mjor onern with CTA is the ssoited rdition exposure, whih hs een ritiized nd ddressed s signifint urden. The estimted verge effetive dose using retrospetive 550 Novemer Deemer 2012 Dignosti nd Interventionl Rdiology Meyer et l.

5 ECG-gting 64 multidetetor CT snner protool for CTA ws previously reported to rnge etween 7 nd 23 msv, depending on the mnufturer, snning tehnique, nd ptient-relted ftors (7). The lifetime ner risk estimtes from CTA re s high s one in 143 for women who reeive sn t ge 20, nd one in 270 for women who re exposed t ge 40 (8). Consequently, dose redution hs eome n importnt onern for oth equipment mnufturers nd end users of this importnt imging modlity. Advnes in CT rdition protetion strtegies for oth routine CT snning nd funtionl rdi CT studies, hve een developed nd re surprisingly si nd esy to implement, leit often underutilized. In reently pulished study, Feuhtner et l. (9) reported n verge ED of 3.8 msv (rnge, msv) for prospetively ECG-triggered dul-pulse CTA using seond-genertion DSCT. This is in ordne with our ED in the ptient s seond CTA study, where we used the sme tehnique. Regrding the ED of high-pith spirl quisition, Ahenh et l. (10) reported n verge ED of 0.87 msv (rnge, msv) in 50 onseutive ptients with ody weight 100 kg nd sinus rhythm 60 pm, whih is similr to our oserved ED of 0.7 msv using the sme tehnique. The results presented in this se were hieved using seond-genertion DSCT; however, the results of other CT snners my differ, nd the rdition dose tehniques desried here nnot e dopted esily. In onlusion, ongoing tehnil innovtion nd reful dpttion of individulized CT protools n drstilly lower rdition exposure nd improve the enefit-risk profile of this tehnology, espeilly in young ptients with omplex hert disese. Conflit of interest dislosure Authors delred no onflits of interest relted to the present rtile. However, U.J.S. is onsultnt for nd is on the spekers ureu of Byer Helthre, Bro, GE Helthre, Medrd, nd Siemens Helthre; U.J.S. s Institution hs grnts from Byer Helthre, Bro, GE Helthre, Medrd, nd Siemens Helthre. Referenes 1. Hoffmn JI, Kpln S, Lierthson RR. Prevlene of ongenitl hert disese. Am Hert J 2004; 147: de Jonge GJ, vn Ooijen PM, Piers LH, et l. Visuliztion of nomlous oronry rteries on dul-soure omputed tomogrphy. Eur Rdiol 2008; 18: Nmi P, Sengupt R, Cheong BY. Multislie omputed tomogrphy of repired nomlous left oronry rtery rising from the pulmonry rtery. Tex Hert Inst J 2008; 35: Wesselhoeft H, Fwett JS, Johnson AL. Anomlous origin of the left oronry rtery from the pulmonry trunk. Its linil spetrum, pthology, nd pthophysiology, sed on review of 140 ses with seven further ses. Cirultion 1968; 38: Moodie DS, Fyfe D, Gill CC, et l. Anomlous origin of the left oronry rtery from the pulmonry rtery (Blnd- White-Grlnd syndrome) in dult ptients: long-term follow-up fter surgery. Am Hert J 1983; 106: Su CS, Tsi IC, Lin WW, Lin FY, Ting CT, Wng KY. Usefulness of multidetetor-row omputed tomogrphy in dignosis of nomlous origin of left oronry rtery rising from the pulmonry rtery. J Chin Med Asso 2010; 73: Husleiter J, Meyer T, Hermnn F, et l. Estimted rdition dose ssoited with rdi CT ngiogrphy. JAMA 2009; 301: Smith-Bindmn R, Lipson J, Mrus R, et l. Rdition dose ssoited with ommon omputed tomogrphy exmintions nd the ssoited lifetime ttriutle risk of ner. Arh Intern Med 2009; 169: Feuhtner G, Goetti R, Plss A, et l. Dulstep prospetive ECG-triggered 128-slie dul-soure CT for evlution of oronry rteries nd rdi funtion without hert rte ontrol: tehnil note. Eur Rdiol 2010; 20: Ahenh S, Mrwn M, Ropers D, et l. Coronry omputed tomogrphy ngiogrphy with onsistent dose elow 1 msv using prospetively eletrordiogrmtriggered high-pith spirl quisition. Eur Hert J 2010; 31: Volume 18 Issue 6 Progressive intr-individul rdition dose redution during CT surveillne of ptient with ALCAPA syndrome 551