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IMAGE INTERPRETATION · CARDIAC IMAGING

Diaphragmatic Attenuation Artifact on Cardiac SPECT

Cardiac SPECT without attenuation correction (top row) vs. with attenuation correction (bottom row)
Cardiac SPECT without attenuation correction (top row) vs. with attenuation correction (bottom row)

Public domain · KieranMaher / Wikimedia Commons · source file

Question

These cardiac SPECT images show an apparent inferior wall perfusion defect on the non-attenuation-corrected images (top) that is no longer visible on the attenuation-corrected images (bottom). What is the most likely cause of the apparent inferior wall defect on the non-corrected images?

  1. ADiaphragmatic attenuation artifact
  2. BRight coronary artery (RCA) territory ischemia
  3. CPrior inferior wall myocardial infarction
  4. DPatient motion during acquisition
Show the answer and explanation

A. Diaphragmatic attenuation artifact

Diaphragmatic attenuation is the most common cause of apparent inferior wall defects on non-corrected cardiac SPECT, particularly in male patients. The diaphragm overlies and attenuates photons from the inferior wall of the left ventricle, creating a false-positive perfusion defect. Attenuation correction (using CT or transmission scan data) compensates for this, and the defect disappears — confirming it as artifact rather than true ischemia or infarction.

More cardiac imaging images

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← Myocardial Perfusion Tracers: Sestamibi and TetrofosminFixed Perfusion Defect: Myocardial Scar on SPECT →

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