Related Experiment Videos
Subtraction gated computed tomography with the dynamic spatial reconstructor: simultaneous evaluation of left and
Insights
This study introduces a novel three-dimensional (3-D) dynamic computed tomography method using the dynamic spatial reconstructor (DSR) to accurately visualize both sides of the heart simultaneously for cardiovascular function studies.
Area of Science:
- Cardiovascular imaging
- Medical physics
- Diagnostic radiology
Background:
- Traditional methods for simultaneous visualization of both heart sides in cardiovascular studies have drawbacks.
- The dynamic spatial reconstructor (DSR) offers a potential solution to these limitations.
Purpose of the Study:
- To develop and validate a novel 3-D dynamic computed tomography technique for simultaneous visualization of the right and left heart chambers.
- To assess the accuracy of this technique in estimating left ventricular muscle mass.
Main Methods:
- Utilized the DSR to acquire 60/s scans during dextro- and levophases after contrast injection in anesthetized dogs.
- Generated sequential 3-D volume images and employed digital subtraction of right and left heart phases.
- Developed a method to combine modified right and left ventricular phase images for enhanced visualization.
Main Results:
- The DSR technique successfully generated sequential 3-D volume images representing cardiac cycles.
- Subtraction and addition of phase images resulted in equally enhanced left and right ventricular chambers.
- LV muscle mass estimation showed a high correlation (0.999) with postmortem measurements, with a mean discrepancy of 2.3%.
Conclusions:
- The developed 3-D DSR imaging technique enables accurate, simultaneous visualization of both heart ventricles.
- This method facilitates retrospective analysis, including static and dynamic oblique planar imaging.
- The high accuracy in LV muscle mass estimation validates the technique for cardiovascular function studies.
Abstract:
Three-dimensional (3-D) dynamic computed tomography of the heart with the dynamic spatial reconstructor (DSR) is being used for studies of cardiovascular function. Formerly, continuous infusion of bilateral bolus injections of contrast medium were required to visualize both sides of the heart simultaneously. The DSR was used to circumvent many of the drawbacks of these methods. In anesthetized dogs a bolus of 1 ml/kg body weight contrast medium was injected into the superior vena cava and 60/s scans were performed during the dextro- and levophases of the resulting angiogram. The recorded scan data were used to generate successive volume (3-D) images with a scan aperture time of 0.06 s each. Each scanned cardiac cycle was thus represented by sequential volume images with either the right or left chambers opacified. Matching equal time intervals from the R wave of the electrocardiogram, the volume images of the left heart phase were digitally subtracted (voxel for voxel) from the images of the right heart phase, with all resulting negative voxel values set to zero. Only the contrast enhanced right ventricle (RV) chamber remained in the subtraction images, whose brightness was then scaled to match the brightness of the opacified left ventricle (LV). The modified RV phase images were then added to the LV phase images. The resulting volume images contain equally enhanced LV and RV chambers and can be used for retrospective analysis, including display of static and dynamic oblique planar images. Verification of the accuracy of this technique was made by estimation of LV muscle mass in five dogs. Dynamic spatial reconstructor estimates from subtracted gated images were compared with postmortem measurements. The correlation was 0.999 with a mean discrepancy of 2.3 +/- 0.4% SEM.