Improve Nuclear Medicine Heart Imaging, Compare MRI Results With Single Photon Emission Computed Tomography Imaging

Currently, up to one-third of all nuclear medicine studies are performed for cardiovascular
disorders, and mostly are myocardial perfusion imaging (MPI) using SPECT acquisition. MPI
aims at detection of acute myocardial ischemia and the scarred myocardium and it is
increasingly used to plan myocardial revascularization and to assess the effectiveness of
medical and surgical interventions. However, nonuniform gamma-ray attenuation in the
thoracic region may severely impair the accuracy of SPECT cardiac imaging and frequently
result in image artifacts. Therefore, attenuation corrected must be applied. We have
derived an algorithm (called EM-IntraSPECT) that is able to reconstruct tomographic
cross-sections of a patient from SPECT studies alone. The reconstructed cross-sections in
turn, may be used for attenuation correction of cardiac SPECT images thus improving quality
analysis based of these images. In this research we intend to continue evaluation of the
new attenuation compensation algorithm and to assess the clinical usefulness of this method.
These goals can be reached by comparing the patient's cross sectional anatomical data
reconstructed by EM-IntraSPECT and obtained from MRI. It is proposed that 10 patients
already undergoing nuclear cardiac imaging for clinical purpose, with 99mTc sestamibi or
99mTc radiolabeled red cells will be selected. These patients would be utilized to
reconstruct transmission images and determination of internal anatomical structures in the
thoracic region from SPECT projections alone. Further, direct and quantitative comparison
of the patient's anatomy obtained by the MRI and the SPECT methods will be performed. The
same algorithm would be used for reconstruction of attenuation compensated emission SPECT
cardiac images. Finally, the accuracy and the clinical usefulness of this new, attenuation
corrected cardiac SPECT image reconstruction would be quantitatively evaluated. All these
procedures apply only to the image data and NOT the patient.

Inclusion Criteria:

- subjects scheduled for cardiac SPECT

- subjects 18 years old or older

Exclusion Criteria:

- Females who are pregnant or think that they are pregnant will be excluded in this
study.

- Subjects who have a pacemaker, internal defibrillator, prostheses, artificial heart
valves, cardiac stents, surgical clips, or TENS (transcutaneous electric nerve
stimulator)

- Subjects who are 300 lbs and over