The incidence of cardiac failure continues to increase despite improvements

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1 Dign Interv Rdiol 2007; 13:33-38 Turkish Society of Rdiology 2007 CARDIOVASCULAR IMAGING ORIGINAL ARTICLE Comprison of short nd long xis methods in crdic MR imging nd echocrdiogrphy for left ventriculr function Tuncy Hzıroln, Brış Tşbş, Merve Gülbiz Dğoğlu, Murt Cnyiğit, Gülcn Ablı, Kudret Aytemir, Ali Oto, Ferhun Blkncı PURPOSE The purpose of this study ws to compre long xis nd short xis methods in crdic mgnetic resonnce imging (MRI), nd echocrdiogrphy for the evlution of left ventriculr function nd mss. MATERIALS AND METHODS The study included 15 ptients with history of myocrdil infrction nd 5 ptients with norml ventriculr function who were exmined with crdic MRI nd echocrdiogrphy. Left ventriculr function nd mss nlyses clculted with Simpson s method from short xis imges were compred to the results of horizontl long xis, verticl long xis, nd combined xes methods. In ddition, results obtined from echocrdiogrphy were compred to the short xis method in crdic MRI. RESULTS In the ptient group, there ws no significnt difference between ejection frction clculted by modified Simpson s nlysis in echocrdiogrphy nd short xis imging in crdic MRI. In crdic MRI, there ws significnt difference between ejection frctions ssessed from both horizontl nd verticl long xis imges, nd those ssessed from short xis imges. There ws no significnt difference in both ptient nd control groups between end-distolic volume determined from short xis nd end-distolic volume determined by horizontl long xis, verticl long xis, nd combined long xes. Significnt difference between the ptient nd control groups ws observed in end-distolic volume clculted by modified Simpson s echocrdiogrphic method. CONCLUSION The present study demonstrted tht there were no significnt dvntges of simplified MRI techniques over modified Simpson s method echocrdiogrphy. Therefore, ptients who cnnot be evluted by echocrdiogrphy optimlly should be evluted by short xis cine MRI sequence. Key words: mgnetic resonnce imging echocrdiogrphy ventriculr function, left From the Deprtments of Rdiology (T.H. tuncyhziroln@ yhoo.com, B.T., M.G.D., M.C., F.B.) nd Crdiology (G.A., K.A., A.O.), Hcettepe University School of Medicine, Ankr, Turkey. Received 13 September 2006; revision requested 12 November 2006; revision received 25 December 2006; ccepted 23 Jnury The incidence of crdic filure continues to increse despite improvements in medicl nd interventionl crdiology (1). In order to ccurtely dignose, nd ssess the prognosis nd the need for interventionl tretment, it is importnt to evlute ventriculr mss nd functions in precise nd reproducible wy. In ddition to being ble to follow-up ventriculr functions in these ptients with seril imging, it positively ffects mortlity nd morbidity, providing clinicins the opportunity to overview nd modify the ongoing tretment. Although echocrdiogrphy is widely vilble, inexpensive, nd noninvsive method, it is opertor-dependent nd the coustic window is limited in some ptients. Even in ptients for whom the coustic window is sufficient, inferobsl segments of the myocrdium re hrd to evlute. Moreover, lthough geometric ssumptions used in the quntifiction of ventriculr functions in echocrdiogrphy do not ffect the results in norml ventricles, it is less ccurte with ventricles tht hve undergone remodeling. Unlike echocrdiogrphy, short xis ssessment in crdic mgnetic resonnce imging (MRI) is independent of geometric ssumptions nd informtion bout the entire myocrdium cn be obtined; therefore, dignostic ccurcy with crdic MRI is greter. Currently, crdic MRI hs become the gold stndrd for evluting crdic functions. Ventriculr end-systolic nd end-distolic volumes, ejection frction, stroke volume, systolic nd distolic wll thickness, nd systolic thickening re determined by 8 12-slice short xis imges involving the entire ventricle, from the pex to mitrl vlve level. On the other hnd, ptients with deteriorted crdic functions cnnot tolerte n 8 12-slice brethhold period. Decresing the slice number nd shortening the brethhold period will improve ptient complince during the exmintion; however, less complicted evlution method for crdic MRI, which will obtin equivlent or pproximtely equivlent results with short xis imging, hs not yet been demonstrted. In this study, we evluted the vlue of long xes methods in crdic MRI (horizontl long xis, verticl long xis, nd combined long xes) nd echocrdiogrphy in the determintion of left ventriculr functions s compred to short xis methods. Mterils nd methods The study included 20 ptients (3 femles, 17 mles) referred to our center for the evlution of left ventricle systolic function. Ptient ge rnged between yers (men, 55.4 yers), height rnged between cm (men, 170 cm), weight vried between kg (men, 70.1 kg), nd body surfce re ws between m 2 (men, 1.8 m 2 ). All the ptients in the ptient group hd history of myocrdil infrction (MI). The control group included 5 volunteers whose systolic functions were norml. 33

2 b Figure 1., b. Horizontl long xis multi-segmented cine MR imges tken during the end-distolic phse () nd the end-systolic phse (b). b Figure 2., b. Verticl long xis multi-segmented cine MR imges tken during the end-distolic phse () nd the end-systolic phse (b). All ptients were screened for clustrophobi, pcemker, implnted crdioverter, defibrilltor, non-mri comptible surgicl clips nd prostheses; ptients positive for ny one or more of these were excluded. The ptients with low crdic performnce who were not expected to tolerte the exmintion were lso excluded. The time intervl between evlutions by crdic MRI nd echocrdiogrphy rnged between 1 5 dys nd no chnges in their tretments were mde. The study ws pproved by the locl ethics committee nd written informed consent ws obtined. Crdic mgnetic resonnce imging All the ptients were evluted with 1.5 Tesl MRI system (Philips Inter Achiev; Philips Medicl Systems, Best, the Netherlnds). They were scnned in the supine position with ECG nd breth follow-up pd. A 5-element phsed rry crdic coil ws used for signl collection. We used crdic gted multi-seg- mented cine stedy-stte free precession sequence (blnced turbo field echo). Multi-segmented cine imging prmeters were s follows: TR/TE, 3.1/1.56 ms; flip ngle, 60 ; FOV: mm; mtrix, ; slice thickness, 8 mm; gp, 2 mm. While ech imge ws tken, the ptients were required to hold their breth t the end of expirtion. Low-resolution xil survey imges were obtined first. Pseudoverticl long xis imges were cquired from the xil survey imges. Horizontl long xis (4-chmber) imges (Fig. 1) were plnned ccording to the provided pseudoverticl long xis imges, nd verticl long xis (2- chmber) imges (Fig. 2) were plnned ccording to these horizontl long xis imges. Short xis imges (Fig. 3) were plnned ccording to horizontl long xis imges. In totl, 7 13 imges of ech ptient s left ventricle were tken so s to include the entire ventricle. Men MR scn time ws min. All cquired MR imges were sent to worksttion nd were evluted by 2 rdiologists. Endocrdil nd epicrdil borders were contoured mnully, nd functionl nlysis ws performed with dedicted softwre (ViewForum Crdic Pckge Progrm, Version 3.4; Philips Medicl Systems, Best, the Netherlnds). On the short xis imges, verticl long xis imges, nd horizontl long xis imges, end-systolic nd enddistolic endocrdil, nd end-distolic epicrdil borders were contoured. The first imge of the series ws tken during the end-distolic phse. The smllest nd the lrgest ventriculr cvity sizes t the midventriculr level were used in order to determine the end-systolic nd end-distolic phses, respectively. Endocrdil borders were contoured by differentiting hyperintensity of the blood in the cvity nd the intermedite intensity of the myocrdium. Since the ppillry muscles would lengthen the time for nlysis nd would not 34 Mrch 2007 Dignostic nd Interventionl Rdiology Hzıroln et l.

3 b Echocrdiogrphy Echocrdiogrphic evlution ws performed in the left lterl position using Vingmed System Five GE ultrsound mchine (Horten, Norwy), with 2.5 MHz trnsducer. Prsternl long nd short xis, nd picl 4-chmber imges were cquired. Echocrdiogrphy of ll ptients ws performed by the sme crdiologist. Echocrdiogrphic mesurements were tken bsed on the criteri suggested by the Americn Echocrdiogrphy Assocition. Ptients underwent M-mode nd 2D echocrdiogrphic evlution, respectively. In M-mode evlution (t the mitrl vlvulr level perpendiculr to the long xis of the ventricle), the left ventricle end-distolic dimeter, left ventricle end-systolic dimeter, interventriculr septum width, nd posterior wll thickness from the prsternl long xis imges were mesured. The ejection frction ws clculted from these mesurements. Epicrdil borders were contoured in the end-distolic nd end-systolic imges mde from picl 4-chmber imges. End-distolic nd end-systolic volumes, ejection frction, nd left ventriculr mss were clculted ccording to modified Simpson s method. Figure 3., b. Short xis multi-segmented cine MR imges tken during the end-distolic phse () nd the end-systolic phse (b). ffect the mss nd cvity volume significntly, they were not included in the mss. While defining the epicrdil borders, the septum ws included in the left ventricle. Segments in which blood in the cvity ws circumscribed by the myocrdium by more thn 50% were defined s bsl segments nd were included in the ventriculr cvity. Atri were differentited by their wll structure nd by their dilttion in systole in cine imges, nd were excluded from the ventriculr cvity. Ventriculr outlets were not included in the ventriculr cvity. Simpson s method nd the long xis re-length method were used in the evlution of the short xis nd long xis imges, respectively. In ddition, cvity re nd cvity length determined in verticl nd horizontl long xes were combined by using the formul, V = A B 0.85/L, where V = volume, A = verticl long xis endocrdil cvity re, B = horizontl long xis endocrdil cvity re, nd L = shorter cvity length. Tble 1. Comprison of the reference method to the functionl nlysis methods for determining left ventriculr ejection frctions in the ptient group SA Men vlue (%) Men difference SD P vlue HLA VLA HLA+VLA M-mode, echo ECHO Short xis crdic MRI is the reference nlysis method. SD: stndrd devition; SA: short xis; HLA: horizontl long xis; VLA: verticl long xis; HLA+VLA: combined long xes nlysis; M-mode: M-mode echocrdiogrphy; ECHO: modified Simpson s echocrdiogrphic nlysis from picl 4-chmber view. Sttisticl nlysis The men vlue nd stndrd devition were cquired for ech prmeter. Pired smples t-test ws used for the ptient group. P < 0.05 ws considered sttisticlly significnt. The Sttisticl Pckge for Socil Sciences (SPSS) Stndrd Version for Windows ws used s the sttisticl softwre progrm. Non-prmetric two relted smples test ws used for the control group. Results In totl, 6 ptients were excluded from the study; 3 due to clustrophobi nd 3 becuse they could not tolerte brethholding during scnning. However, ll 6 of the ptients could hve been exmined by echocrdiogrphy prior to crdic MRI. Functionl results of short xis imges were tken s the gold stndrd for the left ventricle. In both the control nd ptient groups, there ws no significnt difference between ejection frctions clculted by Simpson s echocrdiogrphic nlysis nd modified Simpson s short xis imge nlysis. Ejection frctions clculted using M-mode echocrdiogrphy were significntly different from short xis imge nlysis. In crdic MRI there ws significnt difference when left ventricle short xis imge nlysis ws compred to horizontl long xis, verticl long xis, nd combined horizontl nd verticl long xes. In the control group there ws no significnt difference in ejection frctions determined from horizontl long xis, verticl long xis, nd combined long xes in comprison to short xis imges (Tble 1). End-distolic volume determined from horizontl long xis, verticl long xis, nd combined long xes showed no significnt difference from those determined from short xis in both the ptient nd control groups. On the other hnd, end-distolic volume clculted by modified Simpson s method Volume 13 Issue 1 MR imging nd echocrdiogrphy for left ventriculr function 35

4 Tble 2. Comprison of the reference method to the functionl nlysis methods for determining left ventriculr end-distolic volume in the ptient group SA Men vlue (ml) Men difference SD P vlue HLA VLA HLA+VLA ECHO Short xis crdic MRI is the reference nlysis method. SD: stndrd devition; SA: short xis; HLA: horizontl long xis; VLA: verticl long xis; HLA+VLA: combined long xes nlysis; ECHO: modified Simpson s echocrdiogrphic nlysis from picl 4-chmber view. Tble 3. Comprison of the reference method to the functionl nlysis methods for the determintion of left ventriculr end-systolic volume in the ptient group SA Men vlue (ml) Men difference SD P vlue HLA VLA HLA+VLA ECHO Short xis crdic MRI is the reference nlysis method. SD: stndrd devition; SA: short xis; HLA: horizontl long xis; VLA: verticl long xis; HLA+VLA: combined long xes nlysis; ECHO: modified Simpson s echocrdiogrphic nlysis from picl 4-chmber view. Tble 4. Comprison of the reference method to the functionl nlysis methods for the determintion of left ventriculr stroke volume in the ptient group SA Men vlue (ml) Men difference SD P vlue HLA VLA HLA+VLA ECHO Short xis crdic MRI is the reference nlysis method. SD: stndrd devition; SA: short xis; HLA: horizontl long xis; VLA: verticl long xis; HLA+VLA: combined long xes nlysis; ECHO: modified Simpson s echocrdiogrphic nlysis from picl 4-chmber view. Tble 5. Comprison of the reference method to the functionl nlysis methods for the determintion of left ventriculr wll mss in the ptient group SA Men vlue (g) Men difference SD P vlue ECHO Short xis crdic MRI is the reference nlysis method. g: grm; SD: stndrd devition; SA: short xis; ECHO: modified Simpson s echocrdiogrphic nlysis from picl 4-chmber view. 36 Mrch 2007 Dignostic nd Interventionl Rdiology in echocrdiogrphy ws significntly different from the volume determined by short xis, in both the ptient nd control groups (Tble 2). In both ptient nd control groups, end-systolic volume determined by verticl long xis, combined long xes, nd volume clculted by modified Simpson s echocrdiogrphic method did not show significnt difference compred to end-systolic volume determined by short xis imges (Tble 3). As for the stroke volume, there ws no significnt difference between wht ws determined from horizontl long xis nd shot xis imges in both the ptient nd control groups. However, stroke volume determined by verticl long xis nd combined long xes differed significntly from short xis nlysis in the ptient group. Stroke volume clculted by echocrdiogrphic modified Simpson s method ws significntly different between the ptient nd control groups (Tble 4). Moreover, there ws significnt difference in left ventriculr mss determined from echocrdiogrphic 4-chmber imges nd short xis crdic MRI in both of the groups (Tble 5). Discussion In order to determine the prognosis nd tretment regimen for crdic diseses, it is importnt to evlute crdic volumes nd functions. Therefore, it is essentil to determine how the results obtined by other imging methods differ from those obtined by the gold stndrd method, crdic MRI, nd how we cn improve the ccurcy nd ptient complince in crdic MRI (2, 3). Although echocrdiogrphy is the most widely used method in determining ventriculr function, the technicl disdvntges of echocrdiogrphy hve led us to serch for other non-invsive imging methods tht cn nswer clinicl questions in more relible nd rpid fshion (4). Functionl nlysis with crdic MRI, by obtining short xis imges of the ventricles, is independent of geometric ssumption nd is now ccepted s the gold stndrd (5 14). In this study there ws no significnt difference between the ejection frctions obtined by modified Simpson s method, using picl 4-chmber echocrdiogrphic imges, nd the ejection frctions obtined by crdic MRI, from short xis imges, in both the ptient Hzıroln et l.

5 nd control groups. In contrst, previous studies reported significnt difference between these 2 methods. The reson tht our results were not consistent with those of previous studies could be tht our study included smller number of ptients nd only few of these ptients hd severe ventriculr remodeling, such s n neurysmtic left ventricle (15, 16). In 2-chmber nd 4-chmber imges, slices re tken from only one prticulr prt of the left ventricle, nd unless this prt is the one tht hs undergone remodeling the results obtined my be misleding. In the control group, there ws no significnt difference between the ejection frction nlyses mde with M-mode echocrdiogrphy nd with crdic MRI, wheres there ws significnt difference in the ptient group. In M-mode echocrdiogrphy, ventriculr smple is tken from only one segment nd function is estimted from this one smple. Therefore, in remodeled ventricles tht show signs of locl dysfunction, different results hve been obtined (17). Furthermore, slight devitions in ventriculr dimeter mesurements in M-mode echocrdiogrphy led to significntly different clculted results (18). There ws significnt difference in both the ptient nd control groups between the end-distolic volume mesurements tken with echocrdiogrphic re-length method nd crdic MRI short xis mesurements. Limittions due to the coustic window in echocrdiogrphy mke it hrd to evlute the ventricle in distole becuse of the dilttion of the ventriculr cvity during this phse. Additionlly, while performing echocrdiogrphy, it is more difficult to djust the ultrsound bem so tht it psses from the center of the ventricles during the distolic period (19); therefore, ccurte long xis imges of the ventricles cn not be obtined. In ddition to this, the res tht hve undergone remodeling cn not be evluted unless they re included in the view. All of this contributes to inccurcy while evluting end-distolic volume by the re-length method. There ws no significnt difference in both ptient nd control groups between the end-systolic volume mesurements tken with the echocrdiogrphic re-length method nd crdic MRI short xis mesurements. Unlike the difficulties ssocited with evlution during the distolic period, contrction of the ventricles during systole mkes evlution esier nd, therefore, more ccurte. When the myocrdil mss of the left ventricle ws nlyzed using the crdic MRI short xis method nd echocrdiogrphy, significnt difference between the two ws noted. Two primry resons for this were the chllenge in defining the border of the epicrdium nd endocrdium in echocrdiogrphy, nd the geometric ssumption used in this method. End-distolic volume obtined from crdic MRI t horizontl long xis, verticl long xis, nd combined long xes did not significntly differ from the results obtined with the short xis method. However, results were more pproximte in the ptient group. The men difference between the mesurements tken using the combintion of both long xes imges nd the ones tken by using short xis imges ws only 1.2 ml. In the control group, volumes obtined using combintion methods were 10.4 ml lrger. This shows tht the geometric model determined by using combined long xes imges could be used in remodeled ventricles since it includes slices t lest loclly from pthologic myocrdium segments. There ws no significnt difference between the evlution of left ventricle end-systolic volume using crdic MRI short xis nlysis nd the evlution by crdic MRI verticl long xis nd combined long xes nlysis, nd echocrdiogrphy, either in the control group or in the ptient group. Horizontl long xis nlysis of volume showed no significnt difference in the control group, wheres there ws significnt difference in the ptient group. Therefore, we concluded tht s for the functionl nlysis of end-systolic volume, the geometric model formed by verticl long xis imges would be more ccurte. Left ventricle ejection frction vlues obtined by crdic MRI t horizontl long xis, verticl long xis, nd combined long xes in the ptient group showed significnt difference when compred to vlues obtined using short xis imges. On the other hnd, there ws no significnt difference in the control group. The ssumed ellipsoid geometric model hs led to different results in the ventricles, which hve tken sphericl shpe. In conclusion, the present study demonstrted tht there were no significnt dvntges of simplified crdic MRI methods over modified Simpson s method echocrdiogrphy. Therefore, ptients who cnnot be evluted by echocrdiogrphy, optimlly should be evluted using short xis cine MRI sequence. References 1. Schocken DD, Arriet MI, Leverton PE, Ross EA. Prevlence nd mortlity rte of congestive hert filure in the United Sttes. J Am Coll Crdiol 1992; 20: Reichek N. Mgnetic resonnce imging for ssessment of myocr dil function. Mgn Reson Q 1991; 7: Longmore DB, Klipstein RH, Underwood SR, et l. Dimen sionl ccurcy of mgnetic resonnce in studies of the hert. Lncet 1985; 1: Tsujit-Kurod Y, Zhng G, Sumit Y, et l. Vlidity nd reproducibility of echocrdiogrphic mesurement of left ventriculr ejection frction by coustic quntifiction with tissue hrmonic imging technique. J Am Soc Echocrdiogr 2000; 13: Amico AF, Lichtenberg GS, Reisner SA, et l. Superiority of visul versus computerized echocrdiogrphy estimtion of rdionuclide left ventriculr ejection frction. Am Hert J 1989; 118: Longmore DB, Klipstein RH, Underwood SR, et l. Dimensionl ccurcy of mgnetic resonnce in studies of the hert. Lncet 1985; 1: Rehr RB, Mlloy CR, Filipchuk NG, et l. Left ventriculr volumes mesured by MR imging. Rdiology 1985; 156: Ktz J, Milliken MC, Stry-Gunderson J, et l. Estimtion of humn myocrdil mss with MR imging. Rdiology 1988; 169: Ktz J, Whng J, Boxt LM, Brst RJ. Estimtion of right ventriculr mss in norml subjects nd in ptients with primry pulmonry hypertension by nucler mgnetic resonnce imging. J Am Coll Crdiol 1993; 21: Semelk RC, Tomei E, Wgner S, et l. Norml left ventriculr dimensions nd function: interstudy reproducibility of mesurements with cine MR imging. Rdiology 1990; 174: Semelk RC, Tomei E, Wgner S, et l. Interstudy reproducibility of dimensionl nd functionl mesurements between cine mgnetic resonnce imging studies in the morphologiclly bnorml left ventricle. Am Hert J 1990;119: Pttynm PM, Lmb HJ, vn der Velde EA, et l. Left ventriculr mesurements with cine nd spin-echo MR imging: study of reproducibility with vrince component nlysis. Rdiology 1993; 187: Shpiro EP, Rogers WJ, Beyr R, et l. Determintion of left ventriculr mss by MRI in herts deformed by cute infrction. Circultion 1989; 79: Volume 13 Issue 1 MR imging nd echocrdiogrphy for left ventriculr function 37

6 14. Lorenz CH, Wlker ES, Morgn VL, et l. Norml humn right nd left ventriculr mss, systolic function nd gender differences by cine mgnetic resonnce imging. J Crdiovsc Mgn Reson 1999; 1: Allison JD, Flickinger FW, Wright CJ, et l. Mesurement of left ventriculr mss in hypertrophic crdiomyopthy using MRI: comprison with echocrdiogrphy. Mgn Reson Imging 1993; 11: Bellenger NG, Burgess M, Ry SG, et l. Comprison of left ventriculr ejection frction nd volumes in hert filure by two-dimensionl echocrdiogrphy, rdionuclide ventriculogrphy nd crdiovsculr mgnetic resonnce: re they interchngeble? Eur Hert J 2000; 21: Bellenger NG, Mrcus N, Dvies LC, et l. Left ventriculr function nd mss fter orthotopic hert trnsplnttion: comprison of crdiovsculr mgnetic resonnce with echocrdiogrphy. J Hert Lung Trnsplnt 2000; 19: Teichholz LE, Kreulen T, Hermn MV, Gorlin R. Problems in echocrdiogrphic volume determintions: echocrdiogrphic-ngiogrphic correltions in the presence or bsence of synergy. Am J Crdiol 1976; 37: Kim WY, Sogrd P, Kristensen BO, Egebld H. Mesurement of left ventriculr volumes by 3-dimensionl echocrdiogrphy with tissue hrmonic imging: comprison with mgnetic resonnce imging. J Am Soc Echocrdiogrphy 2001; 14: Mrch 2007 Dignostic nd Interventionl Rdiology Hzıroln et l.