Multi-modality Imaging of Ischemia With 18F-FDG PET and CTA

Direct Imaging of Ischemia With 18F-FDG PET Imaging Combined With Coronary Anatomy From CT Coronary Angiography

Coronary artery disease results in narrowing of the blood vessels supplying oxygenated blood to the heart muscle. Diagnosis in patients with symptoms of chest pain is now quickly done with CT coronary angiography. This x-ray test can show narrowed blood vessels but has limited ability to predict the severity of the narrowings in some cases. We have described a new approach using PET exercise 18F-FDG imaging as a method to image areas of heart muscle not getting enough blood during exercise stress. The 18F-FDG images are co-registered with the CT anatomy from the CTA to provide direct evidence of the consequences of the narrowing.

The Investigators and others have demonstrated direct imaging of myocardial ischemia using 18F-Fluorodeoxyglucose (18FDG) with exercise or dipyridamole stress and positron emission tomography (PET) or single photon emission computed tomography (SPECT). This approach with "hot-spot" imaging may have greater diagnostic accuracy for ischemia than conventional "cold-spot" myocardial perfusion imaging. Recent advances in multi-modality imaging permit fusion of CTA images with PET or SPECT perfusion images and functional assessment of anatomical CAD. Registration of the 2 data sets can be optimized using the CT acquired with the PET or SPECT15. 18FDG uptake as a marker for ischemia can be directly related to the coronary anatomy and guide revascularization.

Radiopharmaceutical, 18FDG PET, CTA, Multi-modality imaging, Metabolic Imaging of Ischemia, Myocardial blood flow, Myocardial blood flow reserve

Positron Emission Tomography nuclear stress scan following either pharmacologic or treadmill stress test with radiopharmaceutical injection at peak stress or within 1 hour following peak stress.

Exercise Stress Testing. All patients will undergo a symptom-limited exercise treadmill test using the Bruce protocol after a 24 hour high fat, low carbohydrate diet and an overnight fast. Persantine Stress Testing: Subjects who have undergone Persantine stress protocol for the PET or SPECT will follow the same protocol. A high fat, low carbohydrate diet for 24 hours and a 12 hour overnight fast will precede the study stress scan. Anti-anginal medications will be withheld on the morning of the exercise test. 18FDG (370 mBq) will be injected at either peak exercise or within 1 hour of peak. Patients will be imaged 60 minutes after radiotracer injection in the supine position in a Discovery 690/VCTLYSO PET system (GE Healthcare, Milwaukee, Wisconsin)

Inclusion Criteria: Patients with suspected CAD referred for CTA and found to have moderate CAD stenoses and 20 normal volunteers with less than 5% probability of CAD. Age ≥ 18 years Exclusion Criteria: Inability to undergo stress protocol due to co-morbidities Pregnancy

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