An essential prelude to image interpretation is to review the planar images which form the raw data of the tomograms. Although the planar images have few counts and only coarse detail can be seen, it is at this stage that potential artefacts are most easily detected. A cine display of the planar images gives the impression of the patient rotating and allows both clinical and technical details to be assessed. Excessive lung uptake, the prognostic importance of which is discussed later in this chapter, can easily be judged. Motion of the patient during the acquisition can be seen and upward creep may also be apparent (case 76).1,2 The phenomenon of upward creep is sometimes seen in stress images following vigorous exercise. As the cardiovascular system returns to the resting state there are changes in heart rate, respiratory rate and redistribution of blood through the body. The mean position of the diaphragm rises and this pushes the heart up. This can lead to an apparent defect which will not be present in the redistribution images, thus simulating a reversible perfusion defect. If there is any doubt whether upward creep has occurred, then the planar images can be summed to show the outline of the heart moving cranially through the acquisition. Another artefact that is easily detected by reviewing the planar images is attenuation from the breast (case 3) or from metallic objects (case 77).
KeywordsSingle Photon Emission Compute Tomographic Myocardial Perfusion Inferior Wall Reversible Defect Reversible Perfusion Defect
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- 2.Mester J, Welle R, Claussen M et al. Upward creep of the heart in exercise thallium 201 single photon emission tomography: clinical relevance and a simple correction method. Eur J Nucl Med 1991 (in press).Google Scholar
- 14.Bonow RO, Dilsizian V, Cuocolo A, Bacharach SL. Identification of viable myocardium in patients with chronic coronary artery disease and left ventricular dysfunction. Comparison of thallium scintigraphy with reinjection and PET imaging with 18F-fluorodeoxyglucose. Circulation 1991;83:26–37.PubMedGoogle Scholar
- 29.Mannting F. Pulmonary thallium uptake: correlation with systolic and diastolic left ventricular function at rest and during exercise. Am Heart J 1990;119:1137–46.,Google Scholar