University of Twente Student Theses


Experimental validation of absolute SPECT/CT quantification for response monitoring in patients with end-stage coronary artery disease

Burgt, A. van de (2019) Experimental validation of absolute SPECT/CT quantification for response monitoring in patients with end-stage coronary artery disease.

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Abstract:Myocardial perfusion scintigraphy (MPS) is based on visual qualitative interpretation and hence interobserver variability might affect clinical decision-making for the patient. Quantification of single photon emission computed tomography (SPECT) imaging enables absolute measurement of treatment efficacy. The aim of this experimental study is to assess quantitative accuracy and precision of iterative image reconstruction (Evolution; Q.Metrix package; GE Healthcare, Little Chalfont, UK), making use of both phantom and patient studies, for potential application of 99mTc-tetrofosmin SPECT/CT in coronary artery disease (CAD) patients. This research consists of a phantom study and an experimental validation study with patient data. An anthropomorphic torso phantom with cardiac insert was filled with technetium (99mTc) and acquired on a SPECT/CT gamma (Discovery 670 Pro; GE Healthcare). Seven sets of 6 acquisitions were evaluated containing a cardiac insert with various defect sizes and configurations. Subsequently, volumes‐of‐interest of the defects were manually drawn on CT to assess the recovery coefficient (RC). Bull’s eye plots were composed to evaluate the uptake per segment. Finally, 99mTc-tetrofosmin SPECT/CT scans were collected retrospectively in ten CAD patients after bone marrow cell treatment and evaluated using Evolution. The phantom study shows that the activity concentration converged after seven iterations (ten subsets) using Evolution. SPECT/CT data were reconstructed with and without Butterworth post-filtering. The average repeatability deviation of all configurations was 2.66% and 2.90% (%SD mean) for the filtered and unfiltered data, respectively. The accuracy after Butterworth post-filtering was lower compared to the unfiltered data with a mean(SD) RC of 0.66 ± 0.06 and 0.71 ± 0.05, respectively (p<0.05). The most artificial defects were found on Bull’s eye plots created with the unfiltered data. Ten patients were included in the patient study. Four patients showed corresponding changes in standardized uptake value pre- and post- BMC injection as to their clinical reported outcome. For the phantom study, absolute quantification of 99mTc related SPECT/CT for CAD patients seems feasible when seven iterations (ten subsets), Butterworth postfiltering and CT-delineation are used. The findings show higher accuracy in larger defects compared to smaller defects. In addition, all defects were visible using either CT-delineation or Bull’s eye plots. The patient study shows insufficient evidence for the use of Evolution in clinical practise. Therefore, further clinical trials with more patients should be performed to investigate the clinical application of Evolution in CAD patients.
Item Type:Essay (Master)
Faculty:TNW: Science and Technology
Subject:33 physics, 44 medicine, 50 technical science in general
Programme:Technical Medicine MSc (60033)
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