DOI:10.2214/AJR.08.1458
AJR 2009; 192:W75-W76
© American Roentgen Ray Society
Penumbra Imaging as a Prognostic Indicator for Acute Myocardial Infarction Using MDCT
I-Chen Tsai,
Kae-Woei Liang and
Wen-Lieng Lee
Department of Radiology and Cardiovascular Center, Taichung Veterans
General Hospital, Taichung, Taiwan
Cardiovascular Research Center, Department of Medicine, and Institute
of Clinical Medicine, National Yang-Ming University, Taiwan, Taiwan
WEB—This is a Web exclusive article.
In the July issue of the AJR, we published an article that
included a patient undergoing acute myocardial infarction diagnosed at MDCT
[1]. Six months after emergent
percutaneous coronary intervention, we ar ranged a follow-up MDCT (with
informed consent) and found that the initial MDCT images during the episode of
myocardial infarction could be of prognostic value for functional recovery. To
our knowledge, this particular clinical implication has not been reported in
the literature before. We write to share this further information with
AJR readers to inspire further research on this topic.
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Fig. 1A —68-year-old man with episode of acute myocardial infarction.
For complete MDCT and catheter coronary angiography images of this patient,
see reference 1 of this letter.
Short-axis MDCT image during diastole of arterial phase of perfusion imaging
obtained during episode of acute myocardial infarction shows wedge-shaped
perfusion defect (outlined area). For fusion cine loop animation, see
Figure S1A in supplemental data online.
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Fig. 1B —68-year-old man with episode of acute myocardial infarction.
For complete MDCT and catheter coronary angiography images of this patient,
see reference 1 of this letter.
Short-axis MDCT image during diastole of delayed phase of infarction imaging
obtained during episode of acute myocardial infarction shows infarcted area
(outlined area), which is slightly smaller than perfusion defect
shown in A. Difference between perfusion defect and infarction is
considered to be penumbra (hibernating viable myocardium). For left
ventricular motion cine in short-axis cine loop animation, see Figure S1B in
supplemental data online.
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Fig. 1C —68-year-old man with episode of acute myocardial infarction.
For complete MDCT and catheter coronary angiography images of this patient,
see reference 1 of this letter.
Follow-up MDCT 6 months after A and B revealed improvement in
coronary artery enhancement and infralateral wall motion. Multiplanar
reformation image of coronary artery shows stent implantation (arrow)
and good enhancement over distal branches of circumflex artery
(arrowheads).
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Fig. 1D —68-year-old man with episode of acute myocardial infarction.
For complete MDCT and catheter coronary angiography images of this patient,
see reference 1 of this letter.
Short-axis MDCT image obtained during systole shows hypokinesia over
infralateral wall. Note that distance between posterior papillary muscle
(arrowhead) and compact layer of infralateral wall (arrow)
is closer than in Figure 2C of reference
1. For motion cine, see Figure
S1D in supplemental data online. Penumbra identified at MDCT at time of acute
myocardial infarction correctly predicted functional recovery that occurred 6
months after coronary revascularization. Please compare cine loops S1B and S1D
for functional recovery.
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A 68-year-old man presented to our emergency department with typical angina
with radiation to the back [1].
ECG and cardiac enzyme test results were normal. MDCT showed significant
stenosis over the distal circumflex artery with faint distal enhancement and
an akinetic infralateral wall of the left ventricle (ejection fraction,
44.2%). Both a perfusion defect and a delayed defect (probably indicating in
farction with microvascular obstruction
[2]) were identified, with the
perfusion defect slightly larger than the delayed defect
[1] (Figs.
1A and
1B; see also supplemental data
online). The subtracted area indicated the pen umbra (hibernating viable
myocardium) [1,
2]. Myocardial infarction was
diagnosed and was further confirmed by the elevated cardiac troponin-I and new
T-wave inversion on ECG immediately after MDCT. Emergent per cutaneous
coronary intervention was arranged shortly thereafter and confirmed the
diagnosis of thrombotic obstruction
[1].
Six months later, the follow-up MDCT showed a patent distal circumflex
artery after stent implantation (Figs.
1C and
1D). The akinesia of the
infralateral wall improved to hypokinesia. The left ventricular ejection
fraction was also increased from 44.2% to 54.5%. The penumbra identified on
MDCT at the time of acute myocardial infarction correctly predicted the
functional recovery that occurred 6 months after endovascular coronary
revascularization.
Several studies have suggested MDCT as a good technique for viability
imaging
[1–4],
but the clinical significance and prognostic implications of the viable
myocardium identified by MDCT are still unclear
[4]. The present case shows
that the viable myocardium identified at MDCT could be a good prognostic
indicator for functional recovery after re vascularized acute myocardial
infarction. If the clinical significance is further proven by clinical study,
MDCT might become the most convenient and easily available
"one-stop-shop" technique for ischemic heart disease because of
its powerful capability for simultaneous coronary, motion, and viability
imaging.
Acknowledgments
This research was supported in part by Taichung Veterans General Hospital
under grants TCVGH-975506C and TCVGH-975504A.
References
- Tsai IC, Lee WL, Tsao CR, et al. Comprehensive evaluation of
ischemic heart disease using MDCT. AJR2008; 191:64
–72[Abstract/Free Full Text]
- Lardo AC, Cordeiro MA, Silva C, et al. Contrast-enhanced
multidetector computed tomography viability imaging after myocardial
infarction: characterization of myocyte death, microvascular obstruction, and
chronic scar. Circulation 2006;113
: 394–404[Abstract/Free Full Text]
- Mahnken AH, Koos R, Katoh M, et al. Assessment of myocardial
viability in reperfused acute myocardial infarction using 16-slice computed
tomography in comparison to magnetic resonance imaging. J Am Coll
Cardiol 2005; 45:2042
–2047[Abstract/Free Full Text]
- Sato A, Hiroe M, Nozato T, et al. Early validation study of
64-slice multidetector computed tomography for the assessment of myocardial
viability and the prediction of left ventricular remodeling after acute
myocardial infarction. Eur Heart J 2008;29
: 490–498[Abstract/Free Full Text]
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