Normal perfusion of the left ventricular myocardium using 320 MDCT

Area of Science:

• Cardiovascular Imaging
• Radiology
• Medical Diagnostics

Background:

• Computed tomography (CT) myocardial perfusion imaging is an emerging technique.
• It relies on density measurements of contrast-enhanced left ventricular (LV) myocardium.

Purpose of the Study:

• To evaluate contrast-enhancement patterns in the LV myocardium in normal individuals using 320-MDCT.
• To investigate the consistent observation of lower Hounsfield unit (HU) values in the lateral LV myocardium.

Main Methods:

• Retrospective evaluation of 21 clinical cases with normal coronary CT angiography.
• Acquisition of scans using a 320-slice MDCT unit.
• Measurement of HU values in 8 regions of the LV myocardium (basal, middle, apical) using standardized ROIs.

Main Results:

• The lateral LV myocardial wall showed significantly lower HU densities compared to the anterior, septal, and inferior walls across all evaluated locations (basal, middle, apical).
• Middle slice lateral wall HU: 79.4 vs. 103.9 (P < 0.001).
• Basal slice lateral wall HU: 82.3 vs. 94.9 (P < 0.001). Apical slice lateral wall HU: 79.9 vs. 100.9 (P < 0.001).

Conclusions:

• Normal LV myocardial enhancement on 320-slice MDCT exhibits significantly lower densities in the lateral wall.
• These variations in density must be considered during CT myocardial perfusion studies to prevent misinterpretation.
• Caution is advised to avoid misrepresenting lower lateral wall densities as perfusion defects.