Atypical pain with positive CTA

and normal myocardial perfusion

F. Mut, M. Kapitan, A. Beltran

Nuclear Medicine Service, Italian Hospital

& CUDIM

Montevideo, Uruguay

• Woman 51 y.o.

• Heavy family history of CAD, no other known risk factors.

• Episodes of atypical chest discomfort.

• Positive exercise test.

• Submitted for CT angiography (CTA), reported as:

Severe proximal LAD stenosis.

No other lesions.

Ca score >1000.

Clinical history

64-slice CT angiography

Cx

3D rendering

LAD lesion (arrow)

• Since Ca score was high, a myocardial perfusion study

was indicated using 99mTc-MIBI with exercise test.

• Patient achieved 101% of maximum predicted heart rate.

• She remained asymptomatic.

• There was a 1 mm ST segment depression.

(see following slide for stress ECG)

aVF V5

Rest

Recovery

Max

Myocardial perfusion study

The perfusion result is consistent with:

a) Small inferior myocardial infarction.

b) Mild anterior myocardial ischemia.

c) Normal.

d) Myocardial infarction + technical artifact.

The perfusion result is consistent with:

a) Small inferior myocardial infarction.

b) Mild anterior myocardial ischemia.

c) Normal.

d) Myocardial infarction + technical artifact.

• The technical quality of the study is adequate.

• No perfusion defects are observed.

What would you do now?

a) Send patient home with medication.

b) Send patient to the cath lab.

c) Indicate stress echocardiography.

d) Hospitalize patient in the coronary care unit.

What would you do now?

a) Send patient home with medication.

b) Send patient to the cath lab.

c) Indicate stress echocardiography.

d) Hospitalize patient in the coronary care unit.

• Despite a normal perfusion study, due to CTA findings and a

positive stress test in a symptomatic patient, coronary

angiography is the most logical option.

LCA - AP LCA - RAO

LCA - LAO

RCA

Angiographic

findings

a) Normal coronary arteries.

b) Multivessel disease.

c) Moderate Cx stenosis.

d) Minimal LAD stenosis.

Coronary angiography shows:

a) Normal coronary arteries.

b) Multivessel disease.

c) Moderate Cx stenosis.

d) Minimal LAD stenosis.

(see next slide)

Coronary angiography shows:

• Mild stenosis (~30%) in proximal LAD can be seen, with

otherwise unremarkable findings.

LCA - AP LCA - LAO

Incomplete visualization of coronary tree

with 64-slice CTA vs. Ca score

N = 1.009

Cheng et al., AHA abstract, Nov 2006

• CTA is sensitive for detecting CAD, however the

technique has limited value in predicting the degree of

stenosis.

• Especially in the presence of arterial calcifications, it is

sometimes difficult to assess the characteristics of a

coronary lesion by CTA.

• Calcium score >300 is associated with poor accuracy of

CTA results (incomplete evaluation of coronary tree).

• Myocardial perfusion has powerful prognostic value and

is not affected by calcium score.

Teaching points

• Zhang S, Levin DC, Halpern EJ, Fischman D, Savage M, Walinsky P.

Accuracy of MDCT in assessing the degree of stenosis caused by

calcified coronary artery plaques. Am J Roentgenol 2008; 191:1676-83.

• Bekkers E, Roos J. Coronary CTA: stenosis classification and

quantification, including automated measures. J Cardiovasc Comput

Tomogr 2009; 3 (Suppl 2):S109-15.

• Halpern EJ, Halpern DJ. Diagnosis of coronary stenosis with CT

angiography comparison of automated computer diagnosis with expert

readings. Acad Radiol 2011; 18:324-33.

• Li JM, Li T, Shi RF, Zhang LR. Comparative analysis between SPECT

myocardial perfusion imaging and CT coronary angiography for

diagnosis of coronary artery disease. Int J Mol Imaging 2012;

2012:253475.

Bibliography