Ultrafast Cardiac Symbia T6 SPECT•CT Imaging with Reversible Anterior Wall Ischemia
Partha Ghosh, MD
Case study data provided by University of Michigan, Ann Arbor, Mich., USA
| Oct 25, 2012
A 65-year-old male patient (225 pounds) with long-standing hypercholesterolemia and a family history of coronary artery disease presented with three month onset of shortness of breath on exertion. Patient was referred for stress myocardial perfusion SPECT study to evaluate for inducible ischemia.
Patient underwent 99mTc-sestamibi myocardial perfusion imaging on a Symbia T6 SPECT•CT system. 99mTc sestamibi was injected at peak heart rate during treadmill stress test followed after one hour by standard SPECT•CT acquisition using low energy high resolution collimator. A low dose CT was performed during free breathing for attenuation correction prior to the SPECT acquisition. LEHR acquisition was followed immediately by an IQ•SPECT acquisition with change of col limator and using Smartzoom collima tors and a cardiocentric SPECT orbit. IQ•SPECT study was performed in total acquisition time of 4 minutes.
The attenuation-corrected IQ•SPECT stress images show severe ischemia in the anterior wall, septum and apex with evidence of partial reversibility in the resting images. The attenuation-corrected LEHR acquisitions show similar extent of ischemia. The LV cavity appears mildly dilated and appears similar in both studies. The calcium score study shows a total calcium score of 1554 with extensive calcification in all three vessels, with maximum involvement of LAD. The extent and severity of anteroseptal ischemia is suggestive of a high grade proximal LAD stenosis. The extent of reversibility suggests that revascularization should lead to significant improvement in perfusion and recovery of wall motion in the LAD territory. The next management step was deemed to be cardiac catheterization for coronary angiography.
This study, although it reflects a relatively straightforward example of reversible LAD territory ischemia demonstrated the diagnostic equivalence of a fast four minute IQ•SPECT study with CT attenuation correction to that of a four times longer standard LEHR SPECT, also with CT attenuation correction.