Stress echocardiography or stress SPECT

Both stress echocardiography and stress myo-cardial perfusion imaging are feasible and effective alternatives to treadmill exercise testing in suitable patients. As indicated previously, imaging studies should be used selectively in patients who will benefit most from the technology, which is associated with considerable additional expense. Both stress echo-cardiography and stress SPECT imaging studies have advantages and disadvantages. The choice between the two tests depends on many factors, including these relative advantages and disadvantages, the individual patient, local expertise, and the anticipated impact of an

Figure 30.4.

Comparison of segmental activity on a resting technetium-99m sestamibi scan with segmental activity on the redistribution image from a resting thallium-201 scan in segments with abnormal contractile function. There was a significant correlation (r = 0.78) between segmental activity on the two scans, although there was some variability. More importantly, activity in those segments with dysfunction which improved after revascularisation generally exceeded 60% of peak counts on both scans. In contrast, dysfunctional segments that did not improve following revascularisation, presumably because they were fibrotic, generally had activity at less than 60% of peak counts on both scans. Reproduced from Udelson et al. Predicting recovery of severe regional ventricular dysfunction. Comparison of resting scintigraphy with thallium-201 and technetium-99m sestamibi. Circulation 1994;89:2552, with permission of the American Heart Association.

Relative advantages of stress echocardiography and SPECT perfusion imaging

• Echocardiography

- higher specificity

- availability/convenience

- structural/valvar evaluation

- lower cost

- higher sensitivity

- higher success rate

- better evaluation of ischaemia in presence of regional dysfunction

- greater evidence base

Modified from ACC/AHA/ACP-ASIM guidelines for the management of patients with stable angina3

Relative advantages of thallium-201 and technetium-99m

- lower cost

- greater evidence base

- assessment of lung uptake

- less bowel/liver uptake

- detection of ischaemia at rest

- better images

- assessment of left ventricular ejection fraction/regional function

- better quantification

- faster imaging protocols imaging study on clinical decision making. Ongoing technical developments related to both techniques should lead to improved diagnostic accuracy.

Choice of radiopharmaceutical Both thallium-201 and technetium-99m based perfusion agents are widely available. Although some laboratories have chosen to use one or the other exclusively, the clinician is often faced with a choice between the two. Most of the advantages of technetium-99m perfusion agents have been better established for sesta-mibi, although they should also theoretically apply equally well to tetrofosmin. In general, the better image quality and ventricular function assessment that is achieved with technetium-99m perfusion agents are the most important considerations, and account for the increasing use of these agents in most nuclear cardiology laboratories.

The Donts of Treadmill Buying

The Donts of Treadmill Buying

Though competitive runners are advised to run on the road, there are several reasons why you should buy treadmills anyway. You might have a family which means that your schedule does not have the flexibility it once had.

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