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The effect of using a combined intervention on extra-cardiac activity in myocardial perfusion imaging : a randomised controlled trial
Dissertation (MRad (Radiography))--University of Pretoria, 2015.
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| Format: | Thesis |
| Language: | English |
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2026
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| _version_ | 1867613730823471104 |
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| access_status_str | Open Access |
| author2 | Vorster, Martin |
| author_browse | Vorster, Martin |
| author_facet | Vorster, Martin |
| collection | Thesis |
| description | Dissertation (MRad (Radiography))--University of Pretoria, 2015. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/110168 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:46.593Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2026 |
| publishDateRange | 2026 |
| publishDateSort | 2026 |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/110168 The effect of using a combined intervention on extra-cardiac activity in myocardial perfusion imaging : a randomised controlled trial Vorster, Martin pippa.bresser@up.ac.za Makanjee, Chandra Rekha Sathekge, Mike Machaba Bresser, Philippa Lynn Myocardial perfusion imaging interfering extra-cardiac activity volume effect hepatic excretion interventions infra-cardiac activity myocardial to extracardiac ratio. Dissertation (MRad (Radiography))--University of Pretoria, 2015. Background: Myocardial perfusion imaging (MPI) is a non-invasive imaging technique that provides accurate, reliable and important results regarding myocardial perfusion to guide patient management. Interpretation of MPI results is often affected by artifacts related to interfering extra-cardiac activity especially in the region of the inferior wall of the heart. Various interventions have been used in an attempt to reduce the frequency and intensity of interfering extra-cardiac activity. However, the effect of extra-cardiac activity present in MPI remains a challenge. Aim: The aim of the study was to investigate the effect of a combined intervention on the frequency and intensity of interfering extra-cardiac activity. Methodology: A total of 230 patients routinely referred to the Nuclear Medicine Department for a two-day stress-rest myocardial perfusion examination were recruited for this randomised controlled study. Patients were randomly assigned to one of two groups after informed consent was obtained. Group A received a single intervention (diluted lemon juice) prior to stress imaging and a combined intervention (diluted lemon juice and soda water) prior to rest imaging. The interventions for group B were reversed for the stress and rest imaging. Early and delayed planar images were taken at stress and rest for both groups. Three interpreters assessed the planar images from 195 patients in terms of the frequency and intensity of interfering extra-cardiac activity. Results: The use of a combined intervention resulted in a non-significant decrease in the frequency and grading of interfering activity and was more effective in the stress studies. The MYO:EXC ratio between groups for the early and delayed rest studies was not significant (p=0.060 and p=0.059). There was a significant negative correlation between the grading score and the early (p=0.021) and delayed (p=0.031) stress MYO:EXC ratio. Gender, BMI, stress method and use of the x combined intervention were identified as significant predictors of the MYO:EXC ratio. The effect of time on interfering extra-cardiac activity showed a highly significant difference (p≤0.001) in the frequency and intensity of interfering extra-cardiac activity as well as the MYO:EXC ratio between early and delayed studies. The difference between stress and rest studies indicated no significant difference in the frequency and grading score of interfering extra-cardiac activity. Analysis of the MYO:EXC ratio indicated a significant (p≤0.05) difference between the early stress and rest studies when the single intervention was used. Discussion and Conclusion: Using a combined intervention to stimulate hepatic excretion of the radiopharmaceutical while at the same utilising the volume effect to push the bowel loops away from the inferior wall of the myocardium is advantageous in MPI. A combined intervention allows for more accurate comparison to be made between stress and rest studies by reducing the difference of MYO:EXC between the two parts of the study. Hence, the combined intervention can be used in clinical practice to overcome any pre-existing differences between stress and rest studies to allow for more accurate image interpretation. Furthermore, delayed imaging in MPI is advocated, thus utilising time as a complementary intervention for female patients or patients with a low BMI where an increase in interfering activity is predicted. The combination of the MYO:EXC ratio and grading scale proved to be effective tools in quantifying the intensity of interfering extra-cardiac activity. The effect of the use of combined interventions in single-day protocols should be explored in terms of improving image quality and reduction of interfering extra-cardiac activity. Radiography MRad (Radiography) 2026-05-15T17:26:32Z 2026-05-15T17:26:32Z 15/10/15 2015 Dissertation http://hdl.handle.net/2263/110168 en application/pdf |
| spellingShingle | Myocardial perfusion imaging interfering extra-cardiac activity volume effect hepatic excretion interventions infra-cardiac activity myocardial to extracardiac ratio. The effect of using a combined intervention on extra-cardiac activity in myocardial perfusion imaging : a randomised controlled trial |
| title | The effect of using a combined intervention on extra-cardiac activity in myocardial perfusion imaging : a randomised controlled trial |
| title_full | The effect of using a combined intervention on extra-cardiac activity in myocardial perfusion imaging : a randomised controlled trial |
| title_fullStr | The effect of using a combined intervention on extra-cardiac activity in myocardial perfusion imaging : a randomised controlled trial |
| title_full_unstemmed | The effect of using a combined intervention on extra-cardiac activity in myocardial perfusion imaging : a randomised controlled trial |
| title_short | The effect of using a combined intervention on extra-cardiac activity in myocardial perfusion imaging : a randomised controlled trial |
| title_sort | effect of using a combined intervention on extra cardiac activity in myocardial perfusion imaging a randomised controlled trial |
| topic | Myocardial perfusion imaging interfering extra-cardiac activity volume effect hepatic excretion interventions infra-cardiac activity myocardial to extracardiac ratio. |
| url | http://hdl.handle.net/2263/110168 |