Imaging Sciences Interesting Cases
Case 186
Samuel Madoff, MD
Clinical Presentation: Patient is a 55-year-old male with congestive heart failure.
Imaging Findings See figure legends.
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| Figure 1: Short-axis contrast-enhanced inversion recovery MR image at the base demonstrates abnormal delayed enhancement involving the inferior and anterolateral walls. A combination of transmural (red arrow) and subendocardial (yellow arrow) enhancement is present. (Move mouse over image to view labels.) |
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| Figure 2: Short-axis contrast-enhanced inversion recovery MR image at the mid-cavity demonstrates abnormal delayed enhancement involving the inferior and anterolateral walls. A combination of transmural (red arrow) and subendocardial (yellow arrow) enhancement is present. (Move mouse over image to view labels.) |
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| Figure 3: Short-axis contrast-enhanced inversion recovery MR image at the apex demonstrates abnormal delayed subendocardial enhancement involving the lateral wall (yellow arrow). (Move mouse over image to view labels.) |
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| Figure 4: Four-chamber steady state free precession MR image demonstrates an abnormally dilated left ventricle. Functional imaging revealed an 18% left ventricle ejection fraction. The right ventricle and atria are also enlarged (not shown). |
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| Figure 5: Seventeen segment model of the left ventricle (AHA). Courtesy of http://www.pmod.com/technologies/doc/pcard/3594.htm |
Diagnosis: Ischemic cardiomyopathy
Discussion: Ischemic cardiomyopathy results from coronary artery disease and subsequent myocardial wall infarction. Cardiac magnetic resonance may provide evaluation of cardiac perfusion, function and viability. Function is evaluated on dynamic images, which display wall motion and chamber size throughout the cardiac cycle. Ejection fraction and other parameters are calculated from this data.
Viability is evaluated on delayed imaging with a gadolinium based contrast agent. Delayed enhancement is compatible with non-viable tissue (i.e. infracted) and is described as either subendocardial or transmural. A hypokinetic wall segment that does not enhance may be hibernating (i.e. hypoxic) and benefit from intervention. Non-ischemic cardiomyopathies demonstrate other patterns of enhancement beyond the scope of this case presentation.
For imaging evaluation, the left ventricle has traditionally been divided into seventeen segments, spiraling counterclockwise from the base to the apex (see Fig. 5).
Typically, the left anterior descending artery supplies the anterior, anteroseptal and inferoseptal segments at the base; anterior and anteroseptal segments at the mid-cavity; anterior, septal and apex segments apically.
The right coronary artery supplies the inferior segment at the base; inferoseptal and inferior segments at the mid-cavity; inferior segment at the apex.
The left circumflex artery supplies the inferolateral and anterolateral segments at the base; inferolateral and anterolateral segments at the mid-cavity; lateral segment at the apex.
Notably, considerable variation in these distributions exists.
Our patient has transmural infarction in the right coronary artery distribution extending from the base to the mid-cavity. Subendocardial infarction is present in the left circumflex artery distribution extending from the base to the apex.
References:
- Bogaert J, Dysmarkowski S, Taylor AM. Clinical Cardiac MRI. Springer, 2005:173-216.