Technetium-99m Gated SPECT Imaging for Evaination of Global and Regional Left

(1)

Technetium-99m Gated SPECT Imaging for Evaination of Global and Regional Left

Ventricular Function: Comparison to Quantitative Echocardiography

Metin GÜRSÜRER, M.D., Ayşe EMRE, M.D., Mehmet AKSOY, M.D., Hakan GERÇEKOGLU, M.D., Selçuk GÖRMEZ, M.D., Kemal YEŞİLÇİMEN, M.D, Birsen ERSEK, MD

Siyami Ersek Thoracic and Cardiovascular Surgery Center, İstanbul, Turkey

GLOBAL VE BÖLGESEL SOL VENTRiKÜL FONKSİYONUNUN DEGERLENDİRİLMESİNDE GATED TEKNESYUM-99m SPECT GÖRÜNTÜ- LEME: KANTiTATiF EKOKARDiYOGRAFi İLE

KARŞILAŞTIRILMASI

ÖZET

Gated SPECT görüntülemeyle, sol ventrikü/ global ve bölgesel

fonksiyonlarının değerlendirilmesindeki

güve-

nilirliğini

ekokardiyografi ile

karşılaştırmak amacıyla,

35 hasta

çaltşnıaya alındı.

Hastalara aym günde olacak

şekilde

gated Tc-99m sestamibi SPECT görüntüleme ve ekokardiyografi

uygulandı.

14 hasta daha önce miyokard infarktüsü (Ml)

geçirmişti.

Ekokardiyografik duvar hare- keti

değerlendirmesi

16 segment/i modelde 4

puan/ı

sis- teme göre

yaptldı.

Bu 16 s egmente uyan gated SPECT görüntü/erde, duvar hareketi ve sisto/ik

kalm-laşma

da 4

puan/ı

sistemlere göre

(sırasıyla

] =normal, O=akine- zildiskinezi; ve ] =normal,

O=kalmlaşma

yok)

değerlendirilerek

ekokardiyografi ile

karşılaşun/dı.

Gat- ed SPECT

lıorizonta/

uzun eksen görüntüler video kamera ile görüntü/enerek

kayıt

aym ekokardiyografi

cihazında

izlendi. Tüm hastalarda planimetrik olarak Simpson meto- du ile EF ölçüldü. Gated SPECT ve ekokardiyograf i

arasında

duvar hareketi (%74, kappa=0.43, p<0.001) ve sisto/ik

kaluılaşma

(%73, kappa =0.43, p<0.001)

açısmdan

oldukça iyi bir segmenter skor

uyumlu/uğu

saptandt. Yine, duvar hareketi ve sisto/ik

katınlaşma

yönünden iki yöntem arasmda belirlenen korelasyon oldukça iyi idi (r=0.93 ve r=0.97). Gatec/ SPECT görüntülerele EF ölçümünün

tekrarlam/abi/irliği

oldukça yüksekti (ay m gözlemcide r=0 .97,

farklı

gözlemciler

arasında

r=0.93). Sonuçta; Gatec/ SPECT görüntülerneyle

kullandığımız

teknik, bölgesel sol ventrikül fonksiyonunun

değerlendirilmesi

ve EF ölçümünde ekokardiyografi ile iyi bir uyum göstermektedir.

Anahtar kelime/er: Gated SP E CT, sol ventrikül fonksiyo- nu, ekokardiyograf i

Received: 6 November 200 I, accepted

ı

3 March 200

ı

Address for correspondence: Metin Gürsürer, MD, Zonguld ak Karaelmas Üniversites i

Tıp

Fakü ltesi

Araştırma

Hastanesi, Kar- diyoloji ABD, 67600 Kozlu, Zonguldak

This study has been presented as a poster presentation in XXth European Congress of Cardiology (Yienna, August 22-26, 1 998).

298 Technetium-99m sestamibi has recently been intro- duced for use with SPECT imaging for evaluation of coronary artery disease

(1-4).

Tc-99m sestamib i ma y be given in high doses due to its short half-life com - pared to thallium-201 and together with its higher energy result in improved image quality (5 ,6). Th e high count density in each image and the stable m- yocardial distribution allow acquisition of gated to- mograms sychronized to the electrocardiogram for assessment of global and segmental myocardial con- traction. The accuracy of gated SPECT imaging for evaluation of regional and global left ventri cular function has been investigated in the last decade

(7,8). Regiona l wall motion and systolic thickening data from gated myocardial perfu sion SPECT has shown good correlation with two-dimensio nal echo- cardiography (7 ,8) . Several studies have shown that left ventric ular ejection fraction can be measured from gated Tc-99m sestamibi SPECT imaging using either automatic quantitation or manual trac ing o f endocardial borders (9- 11 ). In the present study, seg- mental a nd global left ventricular funct ional data from gated SPECT imaging was compared to quanti- tative echocardiographic data and a new technique was developed for calculation of left ventricular ejec tion fraction.

METHODS

Study patients: The study group consisted of 35 patients (24 men,

ı ı

women, m ean age 57± 14 years) referred to our nuclear cardiology laboratory. Fourteen patients had previous myocardial infaretio n and fi ve pati ents had prior coronary artery bypass surgery.

SPECT acquisit ion protocol: All patients were investi-

gated according to a one-day rest/stress protocol. For the

rest studies, tomographi c images were obtained 60 min-

utes after the intravenous injection of 8mCi of Tc-99m

(2)

M. Giirsiirer and et al.: Teclmetiwn-99m Gated SPECf lmagi, gfor Evaluation of Global and Regional Left V emricu/ar

Fwıction

sestamibi. An Else int APEX SPX gamma camcra equipped with a low energy, all purpose collimator with a 20% window centered at the 140 keV photopeak of tc-99m was used. Sixty projections of 20 see each were acquired in step and shoot mode over a 180-degree are on 64x64 matrixes with a zooming factor of 1.4. Patients underwent stress testing with a standard Bruce

treadınili

and at peak stress, 22

ınCi

of Tc-99m sestamibi was injected. After 60 minutes, gated SPECT imaging was performed. The same imaging variables as for the re st study were used with the additi o n of ECG-gated projection for

toınoraphic

recon- struction. At each projection, eight ECG-gated frames per cardiac cycle were acquired. The image reconstruction was performed using a Butterworth filter with a cut-off fre- quency of 0.35 Nyquist and an order of 5 for

Tc-99ın

ses- tamibi perfusion imaging and a Metz filler for ECG-gated SPECT imaging. Ho rizontal J o ng ax is images were taken on a video camera to be disp layed subsequently on echo- cardiography.

Image analysis: Left vent ricul ar images we re scored us- ing a four-point scale on the 20-segment model (O=normal, 1 =equivocal, 2=moderate, 3=severe reduction in radioiso- tope uptake; 4=absent uptake)

(12J.

The gated end-systolic and end-diastolic images were interp reted and segmental wall motio n was scored on a four-point scale (O=akine- s ia/dykinesia, l=severe hypok inesia, 2= moderate hypoki- nesia, 3=normal) in the same 20 segments

<12l.

When func- tional assessment could not be performed because of se- vere reduction or absence of radioisotope uptake, these

segnıents

w ere assigned s co res of zero for w all

nıotion (8J.

Echocardiographic study: Two-dimensional echocardio- g rams were performed after the stress Tc-99m sestam ibi acquisition us ing a Yingmed with 2.5 HHz transducer.

Echocardiograms were examined by two cardiologists un- aware of Tc-99m sestamibi findings. Ejection fracti on w as calculated by planimetric tracing in the four-chamber view. W all motion and systolic thickening were gradedon a four-point scoring system similar to Tc-99m sestamibi imageson the

16-segmenı

model. The basa! and midven- tricular short ax is views on gated SPECT were compared w ith the corresponding basa! and midventri cular short axis v icws on echocardiography, the apical s hort axis infero- septal and high lateral segments on SPECT with apical septal and lateral segments on echocardiography and

verıi

cal lo ng-axis in feroapical and anteroapical segments on SPECT with apical in ferior and anterior segments on ech- ocardiography. G lobal wall motion and systolic thickening scores were calc ulated from the sum of scores of all 1 6 segments.

Statistical analysis: Agreement for g lobal and reg io nal wall motio n scores were assessed by kappa analysis. The correlatio n between

gaıed

SPECT and echocardiographic values for global wall motion and systo lic

ıhickening

were analyzed by Pearson correlation analysis. SPSS 7.5 ver- sion was used for statistical analyis.

RESULTS

The agreement between Tc-99m sestamibi myocar- dial imaging and echocardiograph y for segmental

wall motion and systolic thickening were displayed in Tabtes 1-2. There was a h igh seg me ntal score agreement between gated SPECT and echocardiog- raphy for wall motion (74%, k=0.43, p<O.OO J) and systolic thickening (73%, k=0.43, p<O.OOl ). Pearson correlation analysis also revea led excellent correla- tion between the two me thods for wall motion (r=0.93) and systolic thickening (r=0.97). Repeated measures of ejection fraction on gated SPECT showed high degree of re producibility for the same and different observers (intraobserver r=0.97; inter- observer r=0.93). There was a strong correlation for ejection fraction between gated SPECT an d echocar- diography in patients with and wi thout myocardial infaretion (r=O. 72, r=0.96, respectively). In a su b- group analysis, segmental score agreement between gated SPECT imaging and echocardiography was 0.64 for patients w ith and 0.87 fo r patients without previous myocardia l infarction.

Table 1. Co mparison of segmental score agreement between gated SPECT imaging and echocardiography for wall motion

Gated SPECT Echocardiography

W all Motion Score 3 2

ı

o

3 345 36 5 o

2 56 41 6 o

ı

4 28 8 o

o

ı

4 8 1 8

Table 2. Co mparison of segmental score

agreenıent

between gated SPECT

inıaging

and echocardiography for systolic wall thickening

Gated SPECT Echocardiography

W all Motion Score 3 2

ı

o

Thickening

3 342 44 2 o

2 48 34 6

ı

2 31 16 2

o

^ı

4 6 21

DISCUSSION

An

iınportant

advantage of

technetiuın-99m

sestami- bi over standard

thalliuın-201 iınaging

is the hig h count de nsity whi ch permits gated acquisitio n for evaluation of globa l a nd segme ntal left ventric ular

"'""

(3)

function (5,6)_ Recent studies have investigated the reproducibility and accuracy of technetium-99m ses- tamibi imaging for assessment of left ventricular function. Naj in et al

(13)

showed that the measure- ment of fractional shortening from the diastolic and systolic a nterior technetium-99m sestamibi images correlated well with echocardiographic fractiona l shortening. Tischler et al

(7)

reported that segmental wall motion analysis determined from gated planar technetium-99m sestamibi myocardial imaging was highly reproducible and agreed well with echocardi- ographi c data. Intra- and interobserver agreement was extremely high for global and segmental techne- tium-99m sestamibi wall motion analysis in the ir study . They have suggested that the differe nces in planar versus tomographic technique might be re- sponsible for some of the disagreements between sestamibi im aging and echocardiography and SPECT imaging wou ld be a better approach to com- pare the two techniques. Chua et a l

(8)

also found that gated SPECT imaging showed good correlation with echocardiographic assessment of regional func- tion (r=0.96).

Our results agree with these findings. We found that global and segmental left ventricular function deter- mi ned from gated technetium-99m sestamibi gated SPECT imaging agreed extremely well with echo- cardiography. T here was h igh segmental score

A) r=0.96 GSPECT

75~---~().

70 65 60

55 50

o 8 o

o 00

s ^Cb

o m o

c9

r=0.96

45+---~----~--~----r----r--~

45 50 55 60 65 70 75

ECHOCARDİOGRAPHY

agreement between gated SPECT and echocardiog- raphy for wall motion and systolic thickening in our study (p<O.OOl, p<O.OOI). Moreover, we also found a high degree of intra- and interobserver agreement for global and segmental left ventricular funct ion . Recently, several studies have shown that left ven- tricular ejection fraction can be measured from gated technetium-99m sestamibi SPECT imaging by either automatic ejection fra ction quantitation or by manu- all y tracing the endocardial borders

(9-11).

In these studi es, ejection fraction calc ulated from gated im- ages showed good correlation with standa rd tec h- niques such as radionucl ide angiography and cen- trast ventriculography

(14).

In the present study, re- peated measure s of ejection frac tion on ga ted SPECT showed a high degree of re producibility for the same and different observers. Moreover, the cor- relation for ejection fraction of patie nts with and without myocardial infaretion wa s al so good (r=0.72, r=0.96) (Figure 1).

Our method provides a new technique comparable to for echocard iography determining ejection fraction in patients unde rgoing Gated SPECT.

Stu dy limitations

Assessment of segmental wall motion and systolic wall thickening on gated images mig ht be difficult

B) r=0.72 GSPECT

75~---~

65 o

55 o o

o o

45 o o o o ₀₀ o

35 o

o ^r r=0.72

25+---~~--~----,---,---~

25 35 45 55 65 75

ECHOCARDİOGRAPHY Figure 1.

Correlaıion

for

ejecıion fracıion

between

gaıed

SPECT and echocardiography in patients

wiıhouı

(A) and w i

ılı

myocardial in fare- tion (B).

300

(4)

M. Giirsiirer and et al.:

Teclınetium-99nı

Gated SPECT

lnıagingfor

Evafuarian of Global and Regional Left Ventricu/ar Function

when tracer uptake is severely reduced or absent and this might be responsibl e for some of the disagr ee- ment for wall motion abnormalities between the two methods. An important limitation of post-stress gat- ed myocardial perfu sion SPECT for measuring left ventricular ejection fraction is that a lthough these post-stress im ages accurately define rest left ventric- ular function in patients w ith normal myocardial per- fus ion or only fixed perfusion def ects, these data must be evaluated cautious ly in the setting of rever- s ible m yocardial ischemia (15). Future s tudies in clud- ing a greater population may be planned for compar- ison of wall motion of

ischeınic

segments with the two techniques.

In conclu sion, our data suggest that gated S PECT imaging shows good correlation with echocardiogra- phy for both reg ional and global left ventricular function and calculation of ejection fract ion by this technique shows high degree of reproducibility.

REFERENCES

ı.

Berman DS, Kiat HS, Van Train KF, Germano G , Maddahi J, Friedman JD: Myocardial perfusion imaging with

techneıium-99m

sestamibi: comparative analysis of availabl e imaging protocols. J N uel Med 1994; 35: 68 1-8 2. Van Train KF, Garcia EV, Maddahi J, et al: Multi- center trial validation for

quanıiıaıive

anal ysis of same-day rest-stress

technetiuın-99m

sestamibi myocardial tomo- grams. J Nucl Med 1 994; 35: 609-615

3. Brown KA, Altiand E, Rowen M: Prognostic value of normal technctium-99m sestamibi cardiac imaging. J Nucl Med 1994; 35: 554-7

4. Berman DS, Kiat H, Van Train K, Garcia E, Fried - man J , Maddahi J:

Tc-99nı sestanıibi

imaging in the as- sessment of chronic coronary artery disease.

Senıin

N uel Med 1991; 21:190-212

S. Deutsch E, Vanderheyden J, Gerundini P, et al: De- velopment of nonreducible

technetium-99nı

(III) cations as

nıyocardial

perfusion

^ageııts:

initial experience in hu- mans. J N uel Med 1987; 28: 1870-80

6. Leppo JA, De Puey EG, Johnson LL: A review of cardiac

iınaging

with sestamibi and teboroxime. J Nuc l Med 199 1 ;32:2012-22

7. Tischler MD, Niggel JB, Battle RW, Fairbank JT, Brown KA: Validation of global and segmental left ven- tricular contractile function using gated planar technetium-

99ın

sestamibi myocardial perfusio n

inıaging.

J Am Coll Cardiol 1994;23:141-5

8. Chua T, Kiat H, Germano G, et a l: Gated technetium- 99m sestamibi for simultaneous assessment of stress myo- cardial perfusion, postexercise regional ventricular func- tion and myocardial viability: correlation with echocardi- ography and rest thallium-20 1 scintigraphy. J Am Co ll Cardiol 1994; 23:1107-14

9. De Puey EG, Nichols K, Dobrins ky C: Left ventricu- lar ejection fraction assessed from gated technetium-99m sestamibi SPECT. J N uel Med 1993;34: 1871-6

ıo.

Germano G, Kiat H, Kavanagh PB, et al: Automatic quantitation of ejection frac tion from gated myocardial perfusion SPECT. J Nucl Med 1995;36:2 1 38-47

ll. Boonyaprapa S, Ekmahachi M, Thanachikun N, Jaiprasert W, Sukthomya V, Poramatikul N: Measure- ment of left ventricular ejection fractio n from gated tech-

netium-99nı sestanıibi

myocardial images. Eur J N uel Med 1995; 22: 528-31

12. Berman KS, Kiat H, Friedman TD, et al: Separate acquisition rest thallium/stress technetium-99m sestamibi dua! isotope myocardial perfusion single-photon compu- terized tomography: A el inical validation study. J Am Coll Cardiol 1993; 22: 1455-64

13. Najin YC, Timmis AD, Mai sey MN, et al: The eval- uation of ventricular function using gated myocardial im- aging with Tc-99m MIBI. Eur Heart J 1989; 10:142-8 14. Williams KA, Taillon LA: Left ventricular function in patients with coronary

aıtery

disease assessed by ga ted tomographic myocardial perfusion images: comparison with

assessınent