CASE 
REPORT 
Annals of Nuclear Medicine Vol. 3, No. 2, 89-98, 1989 
Scintigraphic imaging of a case of congenitally corrected transposition of the great vessels and an adult case of single atrium and single ventricle 

Hitoko OGATA,* Tomoaki NAKATA,* Akita ENDOH,* Kazufumi TSUCHIHASHI, Shuji YONEKURA,* Shigemichi TANAKA,* Takatoshi TSUDA,** Masahiro KUBOTA,** and Osamu IIMURA *The Second Department of Internal Medicine, and **Department of Radiology, Sapporo Medical College 

We report on the clinical utility of radionuclide angiography and gated blood pool single emission computed tomography (gated blood pool SPECT) in two patients having congenital heart disease. Both conventional equilibrium radionuclide angiography and gated blood pool SPECT demonstrated the connection of the great vessels with both ventricles in a 15-year-old male patient with a congenitally corrected transposition of the great vessels. In particular, the latter procedure could provide very useful information about the ventricular morphology and inversion which is important for diagnosing this disorder. The second case is an extremely rare 42-year-old female patient with a single atrium and single ventricle. She underwent first-pass and multiple gated blood pool angiography from the anterior, right and left oblique views. The combination of these scintigraphic techniques revealed an insufficiency in anatomical correlations among the single atrium, atrioventricular valve, single ventricle and the great vessels in addition to the connection of superior vena cava with the single atrium, and the atrioventricular valve. Thus, conventional equilibrated angiography from multiple views and gated blood pool SPECT seems to be very reliable not only for anatomical evaluation but also for clinical course observation in patients with complicated congenital heart disease. 
Key words: Congenitally corrected transposition of great vessels, Single atrium and single ventricle, Radionuclide angiography, Gated blood pool tomography 

INTRODUCTION 
RADIONUCLIDE angiography seems an established method to diagnose various cardiac disorders and to evaluate cardiac function. However, there are few reports about scintigraphic imagings of congenital heart disease. Although congenitally corrected transposition of the great vessels was assessed by means of radionuclide techniques by some investigators,1-5 there has not been a blood pool tomographic study 
Received April 8, 1988; revision accepted August 31, 1988. For reprint contact : Hitoko Ogata, Second Department of Internal Medicine, Sapporo Medical College, S 1 , W 16, Chio-ku, Sapporo 060, JAPAN. 
of this disorder. Furthermore, the scintigraphic imaging of single atrium and single ventricle, which is an unusual cardiac disease, is rarely found in adults. We encountered two adult patients with these cardiac malformations the scintigraphic analysis of which was very useful. 
Case 1: A 15-year-old male was admitted to our hospital for further examination of a heart murmur and electrocardiographic abnormalities. He had no symptoms and his physical development was found to be normal. However, he had developed a cardiac murmur at three years of age. On admission, physical examinations revealed a regular heart rhythm of 78/min and a blood pressure of 108/48 mmHg. A grade 3/6 systolic murmur was best heard at the left basilar area and the second heart sound was accentuated with normal respiratory splitting. The electrocardiogram showed a first-degree atrioventricular block, inverted T wave in leads I and aVL and the absence of Q wave in the left precordial leads. The chest X-ray showed that the right cardiac contour was enlarged. Two-dimensional echocardiography suggested that the aorta was the anterior leftward great artery which arose from the left ventricle with right ventricular morphology. The pulmonary artery was posterior and rightward to the aorta (Fig. 1 ). Radionuclide cardioangiography was carried out with 20 mCi of 99m-Tc red blood cells. Equilibrated radionuclide angiography was obtained from the left anterior oblique view with a gamma camera (LFOV, Seale). It showed that the aorta originated above the left-side ventricle which was morphologically suspected to be the right ventricle (Figure 2, top panel). ECG-gated data were acquired continually with a parallel-hole collimator. They were obtained for 60 seconds in every lOdeg. from the left posterior oblique view to the right anterior oblique view by the 10 frame multigate method. The data were then filtered and back projected. Finally each view was obtained. The gated blood pool tomograms from the vertical long axis more clearly demonstrated that the right-side ventricle had a left ventricular morphology and the left-side ventricle was anatomically a right ventricle with an infundibulum (Fig. 2, middle and bottom panels). No right-to-left shunt was shown by first-pass angiography. These results suggested that his cardiac malformation was congenitally corrected transposition of the great vessels (S.L.LT.). The diagnosis was established morphologically by aorto- and ventriculo-graphy with contrast material. The results of the hemodynamic study revealed that the pressure of each chamber and artery was within the normal range. The end diastolic pressure of the left-side ventricle was 2 mmHg and that of the right side ventricle was O mmHg. 

Case 2: A 42-year-old female patient was admitted to our hospital because of severe cyanosis, dyspnea, and orthopnea. She had often suffered from these symptoms since childhood. The diagnosis of a single atrium and single ventricle was made when the second surgical repair was attempted sixteen years after the first surgical procedure which was a Blalock-Taussig's shunt operation on the diagnosis of Tetralogy of Fallot at the age of 14. After that, despite conservative therapy she gradually became worse. On admission, her exercise tolerance was a grade 4/4 of the NYHA classification. The physical examinations revealed a regular heart rhythm of 90/min, blood pressure of 132176 mmHg and respiratory rate of 1 7/min with severe cyanosis and clubbed fingers. There was severe hepato-splenomegaly. The jugular vein was markedly dilated. A grade 5/6 harsh systolic murmur was audible at the right basilar area and a grade 3/6 holosystolic murmur was present at the right mammary area. The second heart sound was single and the third heart sound was heard. The chest X-ray showed dextrocardia and was compatible with severe pulmonary hypertension (Fig. 3). The electrocardiogram revealed an incomplete left bundle branch block and T wave inversion in leads V5R and V6R. The laboratory data showed marked hypoxemia, polycythemia and renal dysfunction. Radionuclide cardiography was carried out with 20 mCi of 99m-Tc red blood cells. First-pass angiograms from the anterior projection demonstrated a connection of the superior vena cava with the left-side cardiac chamber and the left-to-right shunt (Fig. 4). In addition, the retention of radioactive blood pool seemed to show the presence of valvular insufficiency. Gated blood pool scintigraphy was performed from three different angles (Fig. 5). The wall motion analysis revealed that the left-side chamber had the atrial performance and the right-side chamber showed a ventricular contraction during the systole. Although the two chambers seemed to be well separated, no other cardiac cavities were detected by any imagings. The pulmonary trunk was visualized at the back of the aorta. These scintigraphic findings suggested that this patient had a single atrium and single ventricle, where the great vessels originated, and atrio-ventricular valve insufficiency. The diagnosis was confirmed by contrast angiography (Fig. 6). The single ventricle had well developed trabeculae. The aorta arose in front of the pulmonary artery with a subaortic conus. The pulmonary valve was markedly stenotic. In spite of the recovery from congestive heart failure, she suddenly died. An autopsy supported these findings and revealed that the walls of the single ventricle were markedly hypertrophied with well developed trabeculae but no residual septum. The atrioventricular valve was tricuspidal and insufficient. The Blalock-Taussig's shunt was occluded and pulmonary stenosis was evident. 

DISCUSSION 
In almost all cases of congenitally corrected trans-position of the great vessels (CCTGV), operative repair is not necessary. Its diagnosis and clinical course observation is very important because of the possibility of advanced A-V blocks. Several studies of scintigraphic imaging of CCTGV have been reported.1-5 Recently, however, Gal R. et al. (3) showed the usefulness of first-pass and equilibrated radionuclide angiography in CCTGV. The conventional planar angiography does not provide all the precise anatomical information including the morphological assessment of the ventricles. On this point, gated blood pool single photon emission computed tomography (gated blood pool SPECT) appears to be useful in obtaining an accurate delineation of the cardiovascular system and separating the other blood pool from the cardiac chambers.6-8 However, there have been no scintigraphic reports of CCTGV revealed by this particular method. Our study shows that gated blood pool SPECT can contribute to the detailed observation of the morphology of the right and left ventricles and, therefore, is very useful for diagnosing CCTGV. We experienced a very rare adult case with a single atrium and single ventricle.9~12 No scintigraphic assessment of single atrium and single ventricle (SASV) has been reported. Two-dimensional echocardiographic and scintigraphic examinations were very useful in diagnosing it, in particular under the condition of congestive heart failure. First-pass angiography revealed dextrocardia, correlation of the superior vena cava with the single atrium and A-V insufficiency. Gated blood pool angiography from several angles could more clearly demonstrate the anatomical connection of the single atrium, single ventricle and great vessels. The wall motion analysis contributed to the differentiation of an atrium from a ventricle. These scintigraphic observations were compatible with angiographic findings with contrast material and confirmed by autopsy. From these clinical data, we speculate that she had been able to survive till the age of 42 because of pulmonary stenosis and the marked hypertrophy of the single ventricle which was a morphologically the right ventricle despite occlusion of the Blalock-Taussig's shunt. Concerning the long-term compensation of this single ventricle, it cannot always be said that its origin is the right ventricle even if its morphology is like that. In summary, radionuclide angiography can be performed and repeated in patients with severe clinical symptoms without any deleterious side effects. The combination of the first-pass technique, equilibrium radionuclide angiography and gated blood pool SPECT seems to be clinically very useful in diagnosing complicated congenital heart disease and estimating its clinical condition.

REFERENCES 
1 . Attie F, Cuaron A, Marquez M, et al : Quaritative radionuclide angiography in the diagnosis of corrected transposition. AHJ 97: 141-146, 1979 
2. Brendil AJ, Wynchank S, Choussat A, et al : Radionuclide angiography in the diagnosis of congenitally corrected transposition of the great arteries. Clin Nucl Med 9: 383-388, 1984 
3. Gal R, Port SC : Radionuclide angiography in con-genitally corrected transposition of the great vessels in an adult. J Nucl Med 28 : 116-1 18, 1987 
4. Hagan AD, Friedman WF, Ashburn WL, et al : Further application of scintillation scanning techniques to the diagnosis and management of infants and children with congenital heart disease. Circulation 45 : 858-868, 1972 
5. Guit GL, Kroon HM, Chin JG, et al: Radionuclide angiography in the clinical evaluation of cardiac malformations in situs solitus in adults. J Nucl Med 27: 484-490 1986 
6. Moore MD, Murphy PH, Burdine JA : ECG-gated emission computed tomography of the cardiac blood pool. Radiology 134: 233-235, 1980 
7. Barat JL, Brendel AJ, Colle JP, et al : Quantitative analysis of left ventricular function using gated single photon emission tomography. J Nucl Med 25 : 1167-1174, 1984 
8. Nakata T, Murakami H, Inoue M, et al: Qualitative determination of infarct segment by Fourier analysis using gated cardiac pool emission computed tomography. J Cardiogr 16 : 873-884, 1986 (in Japanese)9. Goldberg HL, Sniderman K, Devereux R : Prolonged survival (62 years) with single ventricle. Am J Cardiol 52: 214-215, 1983 
10. Elliott LP, Bream PK, Gessner IH: Single and common ventricle, In Heart disease in Infants, Children and Adolescents, 2nd ed, Moss AJ, Adams FH, Emmanouilides GC (ed), Baltimore, The Williams & Wilkins Co., 1978, pp 381-393 
11 . Moodie DS, Ritter DG, Tajik AJ: Long-term follow-up in the unoperated univentricular heart. Am J Cardiol 53: 1124-1128, 1984 
12. Feigenbaum H : Single ventricle, In Echocardiography, 4th ed, Philadelphia, Lea & Febiger, 1986, pp 430-437