[Radial long-axis tomography: a new reconstructing algorithm for thallium-201 myocardial SPECT].

Area of Science:

• Nuclear Medicine
• Cardiovascular Imaging
• Medical Physics

Background:

• Conventional long-axis (L-A) tomograms in thallium-201 SPECT are reconstructed parallel to midventricular planes.
• This limits optimal visualization of myocardial distribution, particularly at the cardiac apex.

Purpose of the Study:

• To develop and evaluate a new algorithm for reconstructing rotated L-A tomograms.
• To longitudinally observe thallium-201 myocardial distribution and improve visualization of the cardiac apex.
• To introduce a new analysis technique for thallium-201 distribution in L-A tomograms.

Main Methods:

• Developed a novel algorithm for reconstructing "radial L-A tomograms" by rotating around the L-A axis.
• Transformed short-axis (S-A) tomogram coordinates to polar coordinates for reconstruction.
• Created a 2D polar map by analyzing myocardial count profiles in basal and apical regions.

Main Results:

• Demonstrated the method's usefulness in detecting apical myocardial ischemia using a cardiac phantom.
• Radial L-A tomography provided precise information on perfusion defects, especially in apical regions.
• Application to exercise/redistribution studies in patients with effort angina confirmed its clinical utility.

Conclusions:

• The new radial L-A tomographic method enhances the longitudinal observation of thallium-201 myocardial distribution.
• This technique offers superior visualization of the cardiac apex and improved detection of apical ischemia.
• Radial L-A tomography is valuable for assessing perfusion defects in clinical settings, particularly for effort angina.