![]() ![]() Prone 201Tl myocardial perfusion SPECT has been shown to improve left ventricular inferior wall counts compared to supine imaging, thus minimizing diaphragmatic attenuation. Filling the stomach with water caused no marked differences in Tc-99m MPS with or without AC.Ī stomach filled with large amounts of water causes (mild) infero-lateral wall defects in Tl-201 MPS a stomach filled with air causes a strong scintigraphic overexpression of the infero-lateral wall in both Tl-201 and Tc-99m MPS which can be compensated with AC. In Tc-99m MPS, filling the stomach with air also resulted in a higher activity in the infero-lateral wall, which normalized when AC was applied. In Tl-201 MPS, filling the stomach with air caused an increase of activity in the infero-lateral wall, whereas filling the stomach with 1 l of water resulted in a slight decrease of activity in the infero-lateral wall. For Tc-99m, transmission scans for attenuation correction (AC) were also obtained. MPS was recorded with an empty stomach, a stomach filled with 0.5 or 1 l of water, or with 0.5 or 1 l of air. To study the effect of a 'cold stomach', caused by either air or water, on Tl-201 and Tc-99m myocardial perfusion single-photon emission computed tomography (MPS).Ī stomach insert was created in a thorax phantom. Therefore, it is feasible to enable AC for a dedicated cardiac SPECT or SPECT standalone scanners. The proposed attenuation maps showed good agreement with the CT-based attenuation map. Proposed attenuation correction and computed tomography based attenuation correction average myocardial perfusion count was significantly higher than that in non-AC in the mid-inferior, mid-lateral, basal-inferior, and lateral regions (p<0.001). The mean, and standard deviation of the mean square error and structural similarity index measure of the female stress phase between the proposed attenuation maps and the CT attenuation maps were 6.99☑.23% and 92☒.0%, of the male stress were 6.87☓.8% and 96☑.0%. Segmental myocardial counts of a 17-segment model from these databases were compared based on the basis of the paired t-test. The CT-based attenuation maps were used for validation with which cardiac SPECT/CT data of 38 patients were included. Pre-defined attenuation coefficients for given photon energies were assigned to generate attenuation maps. ![]() In-house developed non-rigid registration algorithm automatically aligns the XCAT- phantom with cardiac SPECT image to precisely segment the contour of organs. This study presented a new method for generating an attenuation map directly from emission data by segmentation of precisely non-rigid registration extended cardiac-torso (XCAT)-digital phantom with cardiac SPECT images. Recently developed dedicated cardiac SPECT do not support CT, and thus, scans on these systems are vulnerable to attenuation artifacts. The significance of this new imaging method is discussed and various avenues of research are proposed.Īttenuation correction (AC) using transmission scanning-like computed tomography (CT) is the standard method to increase the accuracy of cardiac single-photon emission computed tomography (SPECT) images. These benefits may also apply to other sorts of cardiac radionuclide imaging. An additional benefit is lessening of artifact by extracardiac activity. It was observed that two-thirds demonstrated moderate or marked lessening of attenuation. With this improved understanding, effervescent granules were given as a clinical, nonresearch measure to nine patients during myocardial scanning. The explanation is based on gravity and anatomy. Despite the historically held view, analysis and review of the literature suggest the defect is likely not diaphragmatic but rather primarily due to attenuation by nearby stomach wall. In radionuclide cardiac imaging, an inferior wall artifactual defect, so called "diaphragmatic attenuation", is particularly common and vexing. Avoidance of falsely positive results depends on distinguishing reality from artifact, in turn depending on images of highest quality. ![]()
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