3 Representative Cases of CT Perfusion and MR Perfusion
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10
Evaluation of Myocardial Ischemia Using Perfusion Study
Fig. 10.9 Diagram of relative upslope (RU) for myocardial perfusion
reserve index (MPRI) using the time-intensity curve
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MR signal
RMU=
Blood pool
MU
S0
x 100 %
LVMU
LVS0
LVMU
Myocardial signal
MU
LVS0
S0
TO
a
TTP
Time
b
c
Fig. 10.10 (a) CT angiography of RCA in rest scan shows >70 % stenosis at the PL (arrow). (b) Stress perfusion CT study shows transmural
perfusion defect at the mid-inferior wall (arrows). (c) Rest scan of CT
d
shows reversibility of perfusion defect. MR stress (d) or rest (e) scan also
shows the same perfusion defect pattern of the inferior wall. (f) Coronary
angiography shows severe total occlusion of proximal PL (arrows)
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e
Fig. 10.10 (continued)
J.-W. Kang and S.M. Ko
f
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Evaluation of Myocardial Ischemia Using Perfusion Study
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10.3.2 Multi-vessel Disease
10.3.3 Microvascular Angina
Figure 10.11
Figure 10.12
a
c
b
d
Fig. 10.11 Three-vessel disease with reversible perfusion defect. CT
coronary angiography of RCA (a), LAD (b), and LCX (c) shows multiple severe stenosis (arrows). CT stress perfusion images show transmural perfusion defect on the basal inferior and inferolateral wall (d)
and the anterior wall, septal wall, and lateral walls on the mid-ventricu-
lar level (arrows) (e). These defects are reversible on the rest scan (f, g).
The perfusion defects are seen in the same segments on stress perfusion
(arrows) (h, i) and rest perfusion (j, k) study using MRI. (Please see
dynamic scans using MRI (h–k) using QR code) (http://extras.springer.
com/2015/978-3-642-36396-2)
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J.-W. Kang and S.M. Ko
e
g
i
Fig. 10.11 (continued)
f
h
j
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Evaluation of Myocardial Ischemia Using Perfusion Study
Fig. 10.11 (continued)
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k
a
b
c
Fig. 10.12 Stress perfusion MRI shows a ring of subendocardial perfusion defect on the entire basal wall (a, b). However, rest perfusion
MRI reveals a normal finding (b). CT angiography reveals normal coronary arteries (c)
J.-W. Kang and S.M. Ko
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10.3.4 Additional Value of CT Perfusion
and MR Perfusion over Coronary
CT Angiography (CCTA)
Figures 10.13 and 10.14
a
c
b
d
e
f
RCA
LAD
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a
Evaluation of Myocardial Ischemia Using Perfusion Study
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b
c
Fig. 10.14 Myocardial ischemia diagnosis and small stent in the
LCX. Low-attenuated lesion at the proximal edge of the LCX stent is
seen which is inconclusive for significant stenosis (arrow) (a). Stress
perfusion image shows transmural perfusion defect on the mid-
inferolateral wall (arrow) (b) (http://extras.springer.com/2015/978-3642-36396-2) and reversible defect on the rest-scan image (c). Coronary
angiography shows severe stenosis at the proximal edge of the LCX
stent (arrow) (d)
Fig. 10.13 Myocardial ischemia diagnosis with severely calcified coronary arteries. CT coronary angiography of RCA (a) and LAD (b) with
heavy calcified plaque failed to demonstrate the coronary artery lumen
clearly due to blooming artifact that resulted from calcified plaque.
Stress perfusion study (c) shows transmural perfusion defect only in the
inferior wall (arrows) and reversible defect on rest study (d). Coronary
angiography shows severe stenosis only in the RCA (arrow) (e). There
was no significant stenosis at LAD (arrow) (f)
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d
J.-W. Kang and S.M. Ko
10.4
Limitations and Artifacts of CT
Perfusion and MR Perfusion
10.4.1 CT Perfusion
Fig. 10.14 (continued)
a
Fig. 10.15 Motion artifact in stress perfusion images. Short-axis views
of 65 % (a) and 46 % (b) of R-R interval are not conclusive for the
perfusion defect. Short-axis view of 87 % (c) provides perfusion defect
• Motion artifact is caused by both cardiac and respiratory
motion. Cardiac motion can lead to the appearance of
focal low-attenuated area alternating with high-attenuated
area, and thus mimicking or masking a perfusion defect.
Using beta-blockers, maximizing temporal resolution,
and selecting motionless images are required for
minimizing the motion artifact. Also, reviewing multiphase images is important; motion artifact is not persistent in all phases (Fig. 10.15).
• Beam-hardening artifact occurs in the contrast-enhanced
left ventricular cavity and the descending thoracic aorta
and in the context of bone (ribs, spine, and sternum). The
typical location is the basal inferior and inferolateral wall
(the left ventricular cavity and the descending thoracic
aorta) and the basal anterior wall (the left ventricular cavity and the ribs). This artifact has also a characteristic triangular shape and does not follow the distribution of the
coronary artery territory. Beam-hardening effect correction algorithm helps in removing the artifact (Fig. 10.16).
• Cone-beam artifact occurs when the center of the patient
does not lie at the isocenter of the scanner. It presents as
low- and high-attenuation bands (Fig. 10.17).
b
of the inferior wall. Coronary angiography shows severe stenosis of the
right coronary artery (d)
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Evaluation of Myocardial Ischemia Using Perfusion Study
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c
d
Fig. 10.15 (continued)
a
b
Fig. 10.16 (a) Beam-hardening artifact at the basal inferior wall (arrow). (b) Beam-hardening effect correction algorithm removes the artifact (arrow)
a
b
Fig. 10.17 Cone-beam artifact in the 2-chamber view (a) and the volume-rendered view (b) (arrows)
