Download Ejection Fraction and Segmental Wall Motion

CIRCULATION
326
22. Ahumada G, Roberts R. Sobel BE: Evaluation of myocardial infarction
with enzymatic indices. Prog Cardiovasc Dis 18: 405, 1976
23. Maroko PR, Libby P, Covell JW, Sobel BE, Ross J Jr, Braunwald E:
Precordial S-T segment elevation mapping: an atraumatic method for
assessing alterations in the extent of myocardial ischemic injury. The
effects of pharmacologic and hemodynamic interventions. Am J Cardiol
29: 223, 1972
24. Muller JE, Maroko PR, Braunwald E: Evaluation of precordial elec-
VOL 57, No 2, FEBRUARY 1978
trocardiographic mapping as a means of assessing changes in myocardial
ischemic injury. Circulation 52: 16, 1975
25. Hillis LD, Askenazi J, Braunwald E, Radvany P, Muller JE, Fishbein
MC, Maroko PR: Use of changes in the epicardial QRS complex to
assess interventions which modify the extent of myocardial necrosis
following coronary artery occlusion. Circulation 54: 591, 1976
26. Maroko PR, Braunwald E: Modification of myocardial infarction size
after coronary occlusion. Ann Intern Med 79: 720, 1973
Evaluation of Left Ventricular Function
(Ejection Fraction and Segmental Wall Motion)
by Single Pass Radioisotope Angiography
JAMES A. JENGO, M.D., ISMAEL MENA, M.D.,
ARNOLD BLAUFUSS, M.D., AND J. M. CRILEY, M.D.
Downloaded from http://circ.ahajournals.org/ by guest on June 15, 2017
SUMMARY Changes in ejection fraction (EF) and segmental wall
motion (SWM) have been shown to be sensitive indicators of left ventricular (LV) function. This information is only obtainable by contrast angiography or gated blood pool scans. Gated studies assume a
fixed geometry for the LV for EF determinations, are lengthy and
limited primarily to the LAO projection. We correlated contrast and
Tc-99m pertechnetate angiograms by single pass radioisotope angiography (immediately preceding the contrast study) in 12 patients.
EF was calculated from the LV time/activity curve and values ranged
from .21 to .72. Angiographic correlation yielded r = 0.97. Regional
LV wall motion was evaluated by dividing a summated cardiac cycle
into 16 frames and dynamically and sequentially displaying these
frames. Regional wall motion evaluation of four LV quadrants correlated well with angiography (r = 0.97). For quantitation these images were divided into four anterior and four inferior segments and
the areas of respective segments were compared and expressed as a
shortening fraction. SWM compared favorably with angiographic
determinations (r ranged from 0.70 to 0.99). Thus, single pass radioisotopic determinations of EF and SWM in the RAO projection correlate well with the angiographic values and provide essential quantitative information on LV function otherwise unobtainable at the
bedside.
THE ABILITY TO monitor hemodynamics in a critically
ill patient, at the bedside, has increased our understanding of
the pathophysiology of heart disease and the effects of
therapeutic interventions on myocardial performance. Indices of left ventricular function which are usually measured
include pulmonary artery wedge pressure, arterial pressure
and cardiac output.1 2 However, none of these parameters
are dependent entirely upon the absolute level of left ventricular function. They are affected by changes in ventricular
compliance and/or fluctuations of the central volume."'
Therefore, measurements of these parameters of left ventricular function are often confusing and may even be misleading.
Ejection fraction has been reported to be a sensitive indicator of left ventricular function4 but it can also be misleading since it varies with changes in both afterload and
preload, independent of changes in left ventricular function.5
Segmental wall motion has been shown to be one of the most
sensitive indicators of left ventricular function"8 but until
recently 'has only been obtainable during cardiac
catheterization.
Gated cardiac blood pool scans have been shown to be
useful in determining ejection fraction and qualitatively
evaluating regional wall motion.9 These studies are limited
by assuming a fixed geometry for the left ventricular ejection
fraction calculation, and by requiring lengthy acquisition
times and a stable cardiac rhythm. They also are limited
primarily to the left anterior oblique projection. The
technique of single pass radioisotope angiography provides
rapid bedside determination of ejection fraction and quantitation of segmental wall motion in the critically ill patient.
From the Divisions of Cardiology and Nuclear Medicine, Harbor General
Hospital, Torrance, California.
Address for reprints: James A. Jengo, M.D., Harbor General Hospital,
Division of Cardiology, 1000 West Carson Street, Torrance, California
90509.
Received May 16, 1977; revision accepted September 1, 1977.
Methods and Materials
Twelve patients, age 27 to 67 (mean 51) years, were
studied. Three patients had valvular heart disease, and nine
patients had symptomatic coronary artery disease. All
patients required cardiac catheterization for diagnosis and
evaluation of coronary artery disease and/or evaluation of
myocardial function.
The studies were performed in the cardiac catheterization
laboratory. Using standard techniques a Swan-Ganz
catheter was positioned in the right pulmonary artery and
another catheter in the body of the left ventricle. The patient
was placed in the 300 right anterior oblique projection.
Twenty-five millicuries of Technetium-99m (2 ml of sodium
pertechnetate) was placed in an extension tube connected to
the distal lumen of the Swan-Ganz catheter. Ten milliliters
of 5% dextrose solution was then rapidly injected through
the extension tubing to achieve a bolus injection of the Tc99m pertechnetate.
Imaging was accomplished using an Ohio Nuclear por-
SINGLE PASS ISOTOPE ANGIOGRAPHY/Jengo et al.
327
Data Analysis
Downloaded from http://circ.ahajournals.org/ by guest on June 15, 2017
FIGURE 1. Composite image of the left ventricle and aorta in enddiastole (RAO projection). Isocontours are superimposed on the
image demonstrating a "pinch' or break in the isocontour defining
the level of the aortic valve. A region of interest (white line) is then
drawn through the aortic valve plane to encompass the approximate
area of the left ventricle. The mitral valve plane is approximated by
connecting the right border of the aortic valve to the inferobasilar
outline immediately below it.
table scintillation camera (series 120) equipped with a low
energy high resolution parallel hole collimator. Data were
recorded onto one-half inch magnetic tape at a speed of 50
inches per second, resulting in a data density of approximately 30,000 counts per second. The data were acquired for 30 seconds and then the scintillation camera was
removed and a contrast left ventriculogram performed
without changing the position of the patient. The contrast
ventriculogram was performed at a filming speed of 60
frames per second no more than 3-5 minutes after completion of the radioisotope angiogram.
The raw data were then transferred from magnetic tape to
a digital computer (Informatek SIMIS-3) and stored on the
disc in list (event-to-event) mode. The list mode acquisition
was then summed and the resulting composite image displayed on the computer's television monitor in an interpolated 512 X 512 matrix. A region of interest was then
defined encompassing the approximate area of the left ventricle using a keyboard controlled light pen. From this
region of interest a preliminary time-activity curve was
generated. The unit of time was 40 msec. Since changes in
count rate represent changes in ventricular volume the
peaks, or points of highest activity, represent the time of the
largest blood volumes, that is, end diastole. The frames corresponding to the peaks from four successive cardiac cycles
are then added together to yield a composite end-diastolic
image which is displayed on the television monitor. Sequential isocount contours are automatically and sequentially
generated and displayed superimposed on the end-diastolic
image (fig. 1). An indentation or "pinch" results from this
technique and corresponds to an interface or area of low activity between two areas of high activity. This indentation
correlates well with the anatomic location of the aortic
valve. A new "true" region of interest is then manually
drawn through the level of the aortic valve to surround the
area of the left ventricle. The plane of the mitral valve is approximated by extending the region of interest straight down
from the right border of the aorta to the inferobasilar border
of the left ventricle. The true left ventricular time-activity
curve (40 msec time unit) is then plotted and displayed (fig.
2). The ejection fraction is then computed using the technique of sinusoidal analysis.'3 Using this method no correction for background activity need be made since by injecting
the radioisotope into the right pulmonary artery with the
patient in the RAO projection, no activity appears in the
right heart or left lung and therefore there is no background
radioactivity surrounding or overlying the left ventricle.
I~~~~~~~~
FIGURE 2. Radioactivity (y axis) vs time (40 msec units) graph
from the true left ventricular region of interest. Five full cardiac
cycles can be seen where the peaks represent end-diastolic radioactivity and the valleys represent end systole.
FIGURE 3. Left ventricular volume curve with radioactivity (y axis) plottedfor the 16 frames making up the composite cardiac cycle.
The first frame of highest activity corresponds to end diastole,
proceeding through systole to end systole which is represented as the
frame with the lowest activity.
32&8
0l|-~ ~1ftIre Ie.
:f;00~~~~~~~~~~~a
VOL 57, No 2, FEBRUARY 197800
CIRCULATION
I
FC
me
an
Ali
lowe
Downloaded from http://circ.ahajournals.org/ by guest on June 15, 2017
FIGURE 4. a) End-iastolic aind end-systolic Images ofthe lef ventricle. The "~pinch" in the serial i'socontours
demonstrates he level of the aor ~valve plane. A regoiono interest is drawvn throug,h the level of the aortic valve and en-.
cogmpasses the body ofthe L V. The "break points" of the chimney-like projection are used to defne the isocoun width o
the aorta. b) Superimposed end-diastolic and end-systolic otInes. Uniform -wall motion can be seen over the anterior,~~~
aipical and ineoailrwlsoftelf ventrce
Inoder evaut
to
left
ventriculawllmto each
of
foursUccessive cardiac cycles is dividdn 16 frames andthe coqrresponding frames of each cycle ar aded together to
yield one summated or~composite crdiac cyce. The
radio~a_ictivityJfrom the lef veticular rgoof interest fOm
each
of the 16
fraimes sequaentially
yielding,atie
for
cycle, hat is, left ventricular
is
plotted,
a
activity curveJ one cardiac t
volume curve (fig. 3). T'he highest activity corresponds to thie
end-diastolic volum adtelwSt activity to the, endsysofic Voue The highest and lowest points are te
disoe eostae lw(ed ewe h ara of1 th leftl atiumadlfeticl,btnlwbtentelfeti
cln aota Residul acivt (r1ed) ca sillb eni h otcro rmtepeeigcce h peihmg
(iooui ytle hw esto offlowbtentearu n vetil_eacaigtelvl of th irlvle
ytle
hw la uln fteari
FThr is stlnFoulwbtentevnrceadaot.Telwrrgtpnl(n
selcte ;im
f
t 1 m
c
t c
c
root.
329
SINGLE PASS ISOTOPE ANGIOGRAPHY/Jengo et al.
Downloaded from http://circ.ahajournals.org/ by guest on June 15, 2017
selected by the computer as representing end-diastole and
end-systole. The true end-diastolic image thus obtained is
displayed on the television monitor in a 512 X 512 matrix. A
color scale (242 levels) and isocontours are used to define the
level of the aortic valve and the approximate contour of the
ventricle. A region of interest is then drawn through the aortic valve plane to encompass the region of the left ventricle.
A chimney-like projection is drawn over the aortic valve
plane such that the two "break points" correspond to an
isocount width of the aortic valve. Next, the end-systolic image is processed in the same manner taking care to redefine
the level of the aortic valve during end-systole (figure 4a).
Since the heart moves in the thorax with each contraction, it
is important to define carefully the level of the aortic valve
during diastole and during systole, that is, not to assume
that the level of the aortic valve remains the same during the
entire cardiac cycle.
The edge of the ventricle is then found for the area enclosed within these regions of interest. The technique consists of finding the second derivative of the matrix in two dimensions and displaying these points with all others set to 0.
Regional wall motion can then be qualitatively assessed in
two ways. First, the end-diastolic and end-systolic outlines
can be superimposed on the television monitor yielding the
familiar image of wall motion (fig. 4b). Regional wall motion is assessed by dividing the RAO silhouette into four
regions: anterobasal, anteroapical, inferoapical and posterobasal. Wall motion in these segments is compared with that
of the angiographic image and rated as normal, hypokinetic, akinetic or dyskinetic. Independent observations
from three observers were used in evaluating 48 segments
from the 12 patients.
For dynamic evaluation of regional wall motion, the 16
frames or images of the summated cardiac cycle are then
rapidly and sequentially displayed producing a cine display
(fig. 5). The true edge of each of these 16 sequential frames
can be highlighted and the observer thus obtain a cine image
of the "beating edge" of the ventricle.
Quantitation of left ventricular segmental wall motion is
then accomplished. The long axis of the ventricle for end
diastole and end systole is computed by connecting the midpoint of the aortic width (the "break points" of the chimneylike projection) to the apex of the ventricle. The long axis is
then quadrisected, yielding eight segments (four anterior and
four inferoposterior) (fig. 6). This process is carried out
separately for the end-diastolic and end-systolic images. The
area of each of the eight segments is then determined for end
diastole and end systole and the difference in areas is expressed as percent contraction. The same technique is used
for analysis of the contrast-angiographically determined images.
In order to assess the reproducibility of the technique, six
sequential first pass radioisotope angiograms were performed at two minute intervals in each of five patients using
the radioisotope Krypton-8 lm. The technique was similar to
the preceding with the exception that a catheter was first
placed in the left atrium via the transatrial septal route and
the Krypton injected into the left atrium.
Krypton-8 I m is an ultrashort-lived radioisotope, the
product of the decay of Rubidium-81. Krypton-81m has a
half-life of 13 seconds thereby making repeat isotope
angiograms possible within two minutes after the initial in-
END - SYSTOLE
END - DIASTOLE
FIGURE 6. The outlines of the left ventricle (RA O projection) are
seen in both end diastole and end systole. The long axis is
automatically generated connecting the midpoint of the aortic valve
with the apex of the ventricle. The long axis is then automatically
quadrisected for both end diastole and end systole and the areas of
the produced segments are calculated.
jection. The administration was carried out in the following
manner: A specially designed generator was made consisting
of 40 mCi of Rubidium-81 adsorbed onto an ion exchange
column in series with a second isotope-free ion exchange
column. These two columns were housed within a lead container with 4 Fr entrance and exit tubes attached to stopcocks. The system was purged free of air with a 5% solution
of dextrose in water and connected in series to the left atrial
catheter. At the time of injection approximately 2 ml of the
5% dextrose solution was flushed through the generator into
the left atrial catheter and then the resulting activity in the
catheter flushed into the patient's left atrium with a bolus of
5% dextrose solution. The acquisition and processing of the
data were handled the same as for the Technetium-99m
studies.
The student's t-test for paired data, the two-sample rank
test and standard regression analysis for calculating correlation coefficients were used for statistical analysis.1'
Results
Ejection Fraction
The results of ejection fraction determinations in the 12
patients are listed in table 1. These results are compared to
ejection fractions determined from the RAO cineventriculogram in figure 7. Ejection fractions varied from 21% to
72% and the correlation between the two techniques was
good (r = 0.97). The slope of the regression line was 0.81
compared to the ideal value of 1.00.
TABLE 1. Ejection Fraction Determination
Patient
YP
KP
NM
BK
GP
VK
CN
RZ
MB
BR
BN
NL
Radioisotope
angiogram
Contrast
angiogram
.48
.44
.27
.21
.30
.47
.37
.57
.51
.25
.54
.50
.54
.26
.17
.35
.54
.32
.63
.53
.21
.58
.76
.72
CIRCULATION
330
VOL 57, No 2, FEBRUARY 1978
.70-
I.6
40Q .30-/
4
.
n
t
*12
r-0.97
20-
10
.10
.20
40
.60
.70
.30
.SO
EJECTION FRACTION (CONTRAST ANGIOGRAM)
.90
FIGURE 7. Comparison of ejection fractions determined by contrast angiography and single pass radioisotope angiography.
Regression equation: y = 0.81 x + 0.06.
Regional Wall Motion
ISOTOPE ANGIOGRAM
CONTRAST ANGIOGRAM
FIGURE 8. Comparison of regional wall motion by isotope
angiography and contrast angiography. Uniform wall motion is
seen throughout the entire cardiac silhouette by both techniques.
reproducibility with a mean standard deviation of 2.0%.
These data are listed in table 4.
Downloaded from http://circ.ahajournals.org/ by guest on June 15, 2017
Discussion
Results of qualitative assessment of regional wall motion
are listed in table 2. The rank correlation with contrast
angiography for the two techniques is excellent. Examples of
the correlation of the two techniques can be seen in figures 8
and 9.
Segmental Wall Motion
The results of quantitative wall motion analysis are listed
in table 3. The comparison of segmental wall motion for
segments 2 through 7 revealed good correlation (r ranging
from 0.70 to 0.99) and is plotted in figure 10. Poor correlation was found for segments 1 and 8 and can be explained by
the artificial "hand-drawn" superior border for those
segments made when the region of interest is drawn through
the aortic valve plane. The fact that the left atrium occupies
a variable portion of segment number 8 also affected the correlation.
There is good general correlation throughout the entire
range of segmental wall motion: from - 1% to + 62% contractility with areas of dyskinesis being represented as well
as areas of hyperkinesis.
Reproducibility
Determinations in five patients in each of whom six sequential studies were performed showed good
Hemodynamic monitoring at the bedside has increased
our understanding of the pathophysiology of heart disease
and allowed us to make objective measurements of cardiac
function before and after therapeutic interventions.
However, the conventional measures of left ventricular function do not purely reflect pump function but are affected by
other factors such as central volume status and left ventricular compliance.
Ejection fraction is a sensitive indicator of left ventricular
function but can only be determined accurately by contrast
ventriculography or, more recently, gated cardiac blood
pool scans. However, even ejection fraction may not
faithfully reflect changes in ventricular function during ongoing ischemia (affected by both afterload and preload) nor
may ejection fraction reflect the decreased ventricular function in a scarred ventricle when there is compensatory hypercontractility of the remaining viable myocardium.
Therefore, it is necessary to measure segmental wall motion in addition to ejection fraction and the hemodynamic
parameters of left ventricular function. Changes in segmental wall motion have been shown to be sensitive indicators of
ischemia and, conversely, show the return of contractility
upon reversal of ischemia. Thus, besides augmenting the
previous measures of left ventricular function, segmental
TABLE 2. Regional Wall Motion
Anterobasal
Patient
YP
KP
NM
BK
GP
VK
CN
RZ
MB
BR
BN
NL
Isot Cntst
3
2
2
2
1
3
2
2
2
2
2
2
3
2
2
2
1
3
3
2
2
2
3
3
Anteroapical
Isot Cntst
3
2
2
1
2
3
2
2
2
2
2
3
3
2
2
1
2
3
2
3
2
2
2
3
Inferoapical
Isot Cntst
2
3
1
1
2
2
2
2
3
1
2
2
3
3
1
1
2
2
2
2
3
1
2
2
Inferobasal
Isot Cntst
2
2
1
1
2
2
2
3
2
2
2
3
2
2
1
1
2
2
2
3
2
2
2
3
Abbreviations: Isot = isotope angiogram; Cntst = contrast angiogram;
wall motion: 3 = normal; 2 = hypokinetic; 1 = akinetic.
CONTRAST ANGIOGRAM
ISOTOPE ANGIOGRAM
FIGURE 9. Comparison of regional wall motion by isotope
angiography and contrast angiography. Both techniques revealed
diffuse hypokinesis in this patient with severe triple vessel coronary
artery disease.
331
SINGLE PASS ISOTOPE ANGIOGRAPHY/Jengo et al.
TABLE 3. Segmental Wall Motion Determinations (% Contraction)
3
Isot Cntst
2
Isot Cntst
Patient
YP
KP
NM
BK
GP
VK
CN
RZ
MB
BR
BN
NL
48
24
11
17
11
52
18
28
22
13
25
45
72
33
30
35
21
47
48
21
11
7
20
62
14
32
35
15
31
52
37
52
40
27
55
81
66
33
21
4
34
56
28
63
68
29
60
85
Segment number
4
5
Isot Cntst
Isot Cntst
50
27
26
3
38
33
64
45
31
14
41
79
35
24
8
7
22
41
32
25
18
7
20
43
28 15
46 56
3 22
3 -5
19 30
31 27
27 54
29 55
31 60
6 11
29 55
38 70
6
Isot Cntst
7
Isot Cntst
30 20
44 61
3 22
0 -4
22 37
30 25
17 33
40 72
31 57
6 12
42 74
29 59
25
29
-1
8
28
27
20
32
30
10
27
45
r
0.95
0.96
0.70
0.95
0.80
0.99
0.99
0.95
0.99
0.99
0.97
0.96
22
38
18
5
34
18
42
65
60
22
51
84
Abbreviation9: Isot = isotope angiogram; Cntst = contrast angiogram.
a
4
BR
yP
0
Downloaded from http://circ.ahajournals.org/ by guest on June 15, 2017
0
r*'0.95
r*a0.99
a-.
Cn
0
-_
0
0
zo
c-w
0
zw
9.-
'-CN
BN
KP
z
w
0
w
ra
0)
0
20
40
60
r
0
20
40
a
4
0.95
60
0
20
40
r
0 897
60
80
PERCENT SEGMENTAL CONTRACTILITY (CONTRAST ANGIOGRAM)
FIGURE 10. Comparison of segmental wall motion (percent segmental contractility) for isotope angiography
axis and contrast angiography.
wall motion, in itself, is a powerful indicator of regional
myocardial function.
There have been no previous reports on the quantitation
of segmental wall motion (percent contractility) using single
pass radioisotope angiography. This technique has shown
excellent qualitative and quantitative correlation and
reproducibility in the evaluation of segmental wall motion.
With the advances being made in the treatment of acute
myocardial infarction with therapeutic modalities that are
potentially deleterious, the need for fast, accurate and
reproducible evaluations of left ventricular function at the
bedside is obvious.
Single pass radioisotope angiography is easily performed,
rapid (requiring only 30 seconds of data acquisition), does
not alter left ventricular function and can be performed in
any projection. If a radioisotope with a short biological halflife is used (for example 99m-Technetium-DTPA) studies
can be repeated after 2-3 hours.
on
the y
This technique correlates well with contrast angiographic
determinations of ejection fraction and segmental wall motion and allows for serial determinations of left ventricular
function, and therefore is especially applicable to evaluating
TABLE 4. Reproducibility of Ejection Fraction
YP
CN
Patients
RZ
BR
NL
.48
.46
.48
.49
.47
.48
.35
.36
.36
.38
.41
.37
.55
.57
.56
.56
.59
.56
.25
.27
.20
.22
.26
.26
.69
.73
.71
Mean SD
.48 0.01 .37
.77
.70
.74
:
:i
0.02 .57
,
Mean standard deviation: 2.0%.
Mean coefficient of variation: 5.0%.
0.01 .24
-
0.03 .72
i
0.03
CIRCULATION
332
critically ill patients and can be incorporated into the
management of these patients in an intensive care unit setting.
6.
7.
Acknowledgment
8.
We gratefully acknowledge the technical expertise given by Dr. Thomas
Nelson and Mr. Sheldon Chelsy and the secretarial assistance of Mrs. Ann
Lubahn and Ms. Joy Morgridge.
9.
10.
References
11.
Downloaded from http://circ.ahajournals.org/ by guest on June 15, 2017
1. Fisher ML, DeFelice CE, Paris AF: Assessing left ventricular filling
pressure with flow-directed (Swan-Ganz) catheters. Chest 68: 542, 1975
2. Forrester JS, Diamond G, Chatterjee K, Swan HJC: Medical therapy of
acute myocardial infarction by application of hemodynamic subsets. N
Engl J Med 295: 1356, 1976
3. Diamond G, Forrester JS: Effect of coronary artery disease in acute
myocardial infarction on left ventricular compliance in man. Circulation
45: 11, 1972
4. Cohn PF, Gorlin R: Dynamic ventriculography in the role of the ejection
fraction. Am J Cardiol 36: 529, 1975
5. Nakhjavan FK, Natarajan G, Goldberg H: Comparison of ejection frac-
12.
13.
14.
VOL 57, No 2, FEBRUARY 1978
tion and zonal mean velocity of myocardial fiber shortening. Circulation
52: 264, 1975
Herman MV, Heinle RA, Klein MD, Gorlin R: Localized disorders in
myocardial contraction. N Engl J Med 277: 222, 1967
Hamilton GW, Murray JA, Kennedy JW: Quantitative angiocardiography in ischemic heart disease. Circulation 45: 1065, 1972
Theroux P, Ross J Jr, Franklin D, Kemper WS, Sasayama S: Regional
myocardial function in the conscious dog during acute coronary occlusion
and responses to morphine, propranolol, nitroglycerin and lidocaine. Circulation 53: 302, 1976
Kostuk WJ, Ehsani AA, KaMliner JS, Ashburn WL, Peterson KL, Ross J
Jr, Sobel BE: Left ventricular performance after myocardial infarction
assessed by radioisotope angiocardiography. Circulation 47: 242, 1973
Rigo P, Murray M, Strauss HW, Taylor D, Kelly D, Weisfeldt M, Pitt
B: Left ventricular function in acute myocardial infarction evaluated by
gated cinephotography. Circulation 50: 678, 1974
Rigo P, Murray M, Strauss HW, Pitt B: Scintiphotographic evaluation
of patients with suspected left ventricular aneurysm. Circulation 50: 985,
1974
Salel AF, Berman DS, DeNardo GL, Mason DT: Radionuclide assessment of nitroglycerin influence on abnormal left ventricular segmental
contraction in patients with coronary heart disease. Circulation 53: 975,
1976
Schelbert HR, Verba JW, Johnson AD, Brock GW, Alazraki NP, Rose
FJ, Ashburn WL: Non-traumatic determination of left ventricular ejection fraction by radionuclide angiocardiography. Circulation 51: 902,
1975
Goldstein A: Biostatistics. New York, Macmillan, 1964
Early Redistribution
of Thallium-201 after Temporary Ischemia
JEFFREY S. SCHWARTZ, M.D., RICHARD PONTO, B.S., PETER CARLYLE, B.S.,
LEE FORSTROM, M.D., AND JAY N. COHN, M.D.
SUMMARY To define the time course of redistribution of
thallium-201 (251TI), ischemia was induced in seven pigs by temporary
occlusion of the circumflex coronary artery. After 1½ min of occlusion 201T1 and labeled microspheres were injected into the left atrium.
Flow was re-established 4 min after occlusion. Prior to reflow, the
relative activities of 201TI and microspheres in the ischemic area were
similar, but as early as 5 min after reflow the relative 201fT activity
was considerably higher than the relative microsphere activity and
from 15 to 105 min after reflow, relative 201TI activity (average 69% of
that in normal myocardium) continued to be higher than relative
microsphere activity (average 6% of normal). Myocardial arteriovenous differences for 201TI were followed sequentially after 201Tl injection in normal dogs and in dogs with temporary coronary
occlusions. The results suggested both loss of 201TI from normal
myocardium beginning 10 min after 205TI injection and increased extraction of 201TI from the blood pool immediately after release of a
transient occlusion. Redistribution of 201TI therefore begins very soon
after relief of myocardial ischemia and even a short delay in initiating myocardial imaging may decrease the sensitivity of the technique
for detecting transient ischemia.
BECAUSE OF ITS FAVORABLE PHYSICAL AND
BIOLOGIC PROPERTIES 201Tl appears to be the best
myocardial perfusion imaging agent presently available for
intravenous use. Resting 201T1 images have been used for the
detection of myocardial infarction,1 and stress images have
been used for the detection of myocardial ischemia.2 The initial distribution of 201T1 has been shown to reflect regional
myocardial perfusion.3
There has been recent clinical evidence, however, that a
perfusion defect on a stress image fills in over several hours.4
Redistribution has also been demonstrated clinically in
patients with variant angina.5 Thallium-201 injected during
angina resulted in large defects in images performed within
10-20 min of injection. Two or three hours later, after relief
of angina, the defects had filled in.
Redistribution has been studied in the experimental
animal by occluding coronary arteries of dogs for 20 min
during which 201TI and labeled microspheres were injected
into the left atrium.4 After 100 min of reperfusion, the
relative 201TI activity in the previously ischemic area was
significantly higher than the microsphere activity indicating
that redistribution of the 201TI had occurred.
The present study was undertaken to better define the
time course and mechanism of 201TI redistribution. The pig
was used as an experimental animal in the initial portion of
this study because it has a less extensive and less variable
collateral circulation than the dog.67
From the Departments of Medicine and Radiology, University of
Minnesota Medical School, Minneapolis, Minnesota.
Supported in part by a Grant-in-Aid from the American Heart Association, Minneapolis Affiliate.
Address for reprints: Jeffrey S. Schwartz, M.D., University of Minnesota
Medical School, Box 258 - Mayo Memorial Building, Minneapolis,
Minnesota 55455.
Received August 1, 1977; revision accepted October 3, 1977.
Evaluation of left ventricular function (ejection fraction and segmental wall motion) by
single pass radioisotope angiography.
J A Jengo, I Mena, A Blaufuss and J M Criley
Downloaded from http://circ.ahajournals.org/ by guest on June 15, 2017
Circulation. 1978;57:326-332
doi: 10.1161/01.CIR.57.2.326
Circulation is published by the American Heart Association, 7272 Greenville Avenue, Dallas, TX 75231
Copyright © 1978 American Heart Association, Inc. All rights reserved.
Print ISSN: 0009-7322. Online ISSN: 1524-4539
The online version of this article, along with updated information and services, is located on
the World Wide Web at:
http://circ.ahajournals.org/content/57/2/326
Permissions: Requests for permissions to reproduce figures, tables, or portions of articles originally
published in Circulation can be obtained via RightsLink, a service of the Copyright Clearance Center, not the
Editorial Office. Once the online version of the published article for which permission is being requested is
located, click Request Permissions in the middle column of the Web page under Services. Further
information about this process is available in the Permissions and Rights Question and Answer document.
Reprints: Information about reprints can be found online at:
http://www.lww.com/reprints
Subscriptions: Information about subscribing to Circulation is online at:
http://circ.ahajournals.org//subscriptions/