Myocardial perfusion SPECT imaging, a practical guide

1. Introduction 12
1.1. Technical and clinical development 12
1.2. Myocardial perfusion scintigraphy in Europe 13
1.3. Non-invasive imaging in coronary artery disease 14
2. Fundamentals of CAD and imaging 18
2.1. Coronary artery disease 18
2.2. Coronary stenoses and perfusion 19
2.3. Principle of myocardial perfusion scintigraphy 20
3. Indications for myocardial perfusion scintigraphy 24
3.1. Preliminary remarks 24
3.2. Imaging procedures in CAD diagnosis 24
3.3. Indications on trial - Appropriate Use Criteria 27
3.4. Acute coronary syndrome (ACS) 31
3.5. Assessment of viability 32
4. Performing myocardial perfusion SPECT 38
4.1. Preparatory measures 38
4.1.1. Instruction and patient information 38
4.1.2. Patient preparation 38
4.1.3. Before getting started 38
4.2. Stress testing 39
4.2.1. Exercise stress 41
4.2.2. Pharmacological stress 43
4.2.2.1. Vasodilators (adenosine and dipyridamole) 43
4.2.2.2. Side effects of adenosine and dipyridamole 44
4.2.2.3. Digression: Ischaemia under adenosine or dipyridamole 46
4.2.2.4. Combining adenosine or dipyridamole with exercise 47
4.2.2.5. Catecholamines (dobutamine) 47
4.2.2.6. New developments: selective A2a adenosine receptor agonists 48
4.3. Radiopharmaceuticals 48
4.3.1. Thallium-201 49
4.3.2. Tc-99m perfusion radiopharmaceuticals (sestamibi and tetrofosmin) 51
4.3.3. Radiation exposure and recommended activities 51
4.4. Imaging protocols 51
4.4.1. Protocols for Tl-201 51
4.4.2. Protocols for Tc-99m perfusion radiopharmaceuticals 53
4.4.3. Hybrid protocols 54
5. Acquisition technique 56
5.1. Ungated SPECT 56
5.1.1. Patient positioning 56
5.1.2. Camera orbit 56
5.1.3. Circular and non-circular orbits 56
5.1.4. Pixel size and matrix size 57
5.1.5. Step-and-shoot and continuous acquisition 57
5.1.6. Number of projections 57
5.1.7. Time per projection and total time 57
5.2. Gated SPECT 57
5.2.1. Basics - systole, diastole and gates 57
5.2.2. How does gated SPECT work? 57
5.2.3. Short, long and irregular heartbeats 58
5.2.4. Acquisition strategies for gated SPECT 59
5.2.5. Preparation for gated SPECT 61
5.2.6. Gated SPECT acquisition protocols for a dual-head camera 61
5.2.6.1. Acquisition protocol with acceptance window and extra files 61
5.2.6.2. Acquisition protocol without extra files 62
5.2.6.3. Tracking - following the heart rate 62
5.2.6.4. Sampling with 8 or 16 gates 63
5.2.6.5. Gated SPECT and extrasystoles 64
5.2.6.6. Gated SPECT and absolute arrhythmia 65
5.2.6.7. Gated SPECT with Tl-201 or Tc-99m radiopharmaceuticals 65
5.2.6.8. Gated SPECT: prone or supine position? 65
5.3. Attenuation and attenuation correction 66
5.3.1. Physical basis 66
5.3.2. Absorption problems 66
5.3.3. Principle of attenuation correction and artefacts 67
5.3.4. Clinical value of attenuation correction 69
6. Processing 74
6.1. Raw data check 74
6.2. Filtered back projection 74
6.3. Iterative reconstruction 76
6.4. Reorientation 76
6.5. Evaluation of gated SPECT 77
6.5.1. Quality control 77
6.5.2. Display of results and normal values 78
6.5.3. Digression: partial volume effect 79
6.5.4. Accuracy of volumes and LVEF 80
7. Gated SPECT - why and when? 82
7.1. Motivation for gated SPECT 82
7.2. Gated rest, gated stress - or both? 83
7.3. Impact of gated SPECT on diagnosis 85
8. Findings and documentation 88
8.1. Image display 88
8.2. Polar tomograms 88
8.3. Bases of reporting 89
8.4. Quantitative perfusion analysis 90
8.5. Additional findings 92
8.5.1. Transient ischaemic dilatation 92
8.5.2. Lung-heart quotient 93
9. Diagnostic accuracy of myocardial perfusion SPECT imaging 96
9.1. Sensitivity, specificity, likelihood ratios 96
9.2. The false-positive myocardial perfusion scan 97
10. Risk assessment and prognosis 100
10.1. Objective of risk stratification 100
10.2. Cardiac risk categories 100
10.3. Prognostic value of a normal study 100
10.4. Prognostic value of an abnormal study 102
10.5. Prognosis in high pretest CAD likelihood 102
10.6. Incremental prognostic value of cardiac SPECT imaging 103
10.7. Relationsship between ischaemia and infarction 104
10.8. Added value of gated SPECT 105
10.9. Digression: posttest referral bias in prognostic studies 107
11. Myocardial perfusion imaging and treatment decisions 110
11.1. Setting the course with the summed difference score 110
11.2. Patient management 112
12. Special patient groups 116
12.1. Diabetes mellitus 116
12.1.1. Diagnosis and risk stratification in diabetic patients 116
12.1.2. Evaluation of the asymptomatic diabetic patient 118
12.2. Women 120
12.3. Left-bundle branch block 122
13. Key elements of reporting 126
14. References 130
Index 140