Clinical Presentation

An 85-year-old woman with no known coronary artery disease (CAD) is referred for an exercise myocardial perfusion single-photon emission tomography (SPECT) study to evaluate for nonanginal chest pain. Her cardiac risk factors include hypertension. The resting electrocardiogram (ECG) shows normal sinus rhythm and nonspecific T-wave abnormalities. She is on lisinopril and hydrochlorothiazide at the time of testing.

Fig. 32.1

Technique

• The patient had nothing to eat within 4 hours of the test.

• Rest images were acquired 40 minutes after the intravenous injection of 10 mCi of ^99mTc-sestamibi. Images were acquired in the supine position with a two-headed gamma camera with step-and-shoot rotation, 32 projections over a 90-degree arc for each head (64 projections over a 180-degree arc), 30 seconds per projection, and a 64 × 64 matrix.

• Exercise: 9 minutes, 0 second on a Bruce protocol (10.1 METs [metabolic workloads]).

• A 33 mCi dose of ^99mTc-sestamibi was injected during peak stress.

• At 45 minutes after the exercise injection of radiotracer, image data were acquired with settings similar to those used for rest imaging. Gated images were acquired at 8 frames per cardiac cycle.

• Transverse images were reconstructed with a Butterworth filter (order of 5 and cutoff frequency of 0.792 cycles per pixel) for the rest and stress studies.

Image Interpretation

The heart rate increased from 59 beats/min at rest to a peak of 116 beats/min (86% of the age-predicted maximal heart rate), and the blood pressure increased from 140/60 mm Hg at rest to 160/80 mm Hg at peak exercise (rate-pressure product of 18,560). Exercise was terminated because of fatigue. Baseline ECG was normal. There were no symptoms of ischemia.