scholarly journals Effect of Scatter Limitation Correction with Misregistration between Computed Tomography and Positron Emission Tomography on Scatter Correction: A Physical Phantom Study

2017 ◽  
Vol 73 (3) ◽  
pp. 185-193
Author(s):  
Akihiro Furuta ◽  
Hideo Onishi ◽  
Yoshiharu Kangai ◽  
Yoshinori Shigehiro ◽  
Ikuhiro Kawasaki
Keyword(s):  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Scatter Correction ◽  
Phantom Study ◽  
Emission Tomography ◽  
Positron Emission

Respiratory-gated positron emission tomography and breath-hold computed tomography coupling to reduce the influence of respiratory motion: Methodology and feasibility

2009 ◽  
Vol 50 (2) ◽  
pp. 144-155 ◽  
Author(s):  
J. Daouk ◽  
L. Fin ◽  
P. Bailly ◽  
M.-E. Meyer
Keyword(s):  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Respiratory Motion ◽  
Motion Artifacts ◽  
Phantom Study ◽  
Emission Tomography ◽  
Breath Hold ◽  
Positron Emission ◽  
Gated Pet ◽  
Respiratory Signal

Background: Respiratory motion causes uptake in positron emission tomography (PET) images of chest and abdominal structures to be blurred and reduced in intensity. Purpose: To compare two respiratory-gated PET binning methods (based on frequency and amplitude analyses of the respiratory signal) and to propose a “BH-based” method based on an additional breath-hold computed tomography (CT) acquisition. Material and Methods: Respiratory-gated PET consists in list-mode (LM) acquisition with simultaneous respiratory signal recording. A phantom study featured rectilinear movement of a 0.5-ml sphere filled with 18F-fluorodeoxyglucose (18F-FDG) solution, placed in a radioactive background (sphere-to-background contrast 6:1). Two patients were also examined. Three figures of merit were calculated: the target-to-background ratio profile (TBRP) in the axial direction through the uptake (i.e., the sphere or lesion), full-width-at-half-maximum (FWHM) values, and maximized standard uptake values (SUVmax). Results: In the phantom study, the peak TBRP was 0.9 for non-gated volume, 1.83 for BH-based volume, and varied between 1.13 and 1.73 for Freq-based volumes and between 1.34 and 1.66 for Amp-based volumes. A reference volume (REF-static) was also acquired for the phantom (in a static, “expiratory” state), with a peak TBRP at 1.88. TBRPs were computed for patient data, with higher peak values for all gated volumes than for non-gated volumes. Conclusion: Respiratory-gated PET acquisition reduces the blurring effect and increases image contrast. However, Freq-based and Amp-based volumes are still influenced by inappropriate attenuation correction and misregistration of mobile lesions on CT images. The proposed BH-based method both reduces motion artifacts and improves PET-CT registration.

The Potential Value of Hybrid Positron Emission Tomography/Dual-Source Computed Tomography Imaging in Coronary Bypass Surgery

2011 ◽  
Vol 14 (5) ◽  
pp. 283 ◽  
Author(s):  
Andre Plass ◽  
Maximilian Y. Emmert ◽  
Oliver Gaemperli ◽  
Hatem Alkadhi ◽  
Philipp Kaufmann ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Coronary Artery ◽  
Coronary Angiography ◽  
Myocardial Perfusion ◽  
Predictive Value ◽  
Bypass Surgery ◽  
Emission Tomography ◽  
Positron Emission ◽  
Pet Ct

<p><b>Background:</b> We evaluated how comprehensive assessment of coronary artery lesions and their hemodynamic relevance by means of hybrid positron emission tomography (PET) and computed tomography (CT) imaging would affect decision-making in coronary artery bypass surgery (CABG), compared with using invasive coronary angiography (ICA) alone.</p><p><b>Methods:</b> After undergoing ICA, 27 patients (21 men and 6 women; mean SD age, 66 � 10 years) planned for cardiac surgery were scheduled for myocardial perfusion stress/rest evaluation with [13N]ammonia PET and CT coronary angiography. Only ICA was available to the surgeon. Postoperatively, the performed CABG was compared with the hypothetical strategy based on hybrid PET/CT findings (regional coronary flow reserve [CFR], myocardial perfusion defects). Procedures included CABG (n = 18) alone, CABG combined with valve replacement (n = 6), and CABG combined with isolated valve replacement (n = 3). A total of 56 bypass grafts (28 venous and 28 arterial) and 66 distal anastomoses were placed.</p><p><b>Results:</b> CT evaluation showed 93% concordance (66/71) with ICA regarding significant stenoses, with sensitivity, specificity, positive predictive value, and negative predictive value of 93.1%, 98.7%, 94.4%, and 98.4%, respectively. In the PET scan, 16 patients had 1 ischemic region, and 12 patients had 1 scar region, including 5 patients who presented with mixed conditions (scar and ischemia). One patient had a completely normal myocardium. Compared with the performed surgery, PET/CT fusion evaluation showed that of the performed anastomoses, 48% had documented ischemia (with a CFR <2 in 86%), 38% were nonischemic (although a CFR value <2 was found in 78%), and 14% had scar tissue (fixed perfusion defect).</p><p><b>Conclusions:</b> Although <50% of bypasses were placed to areas with myocardial ischemia, the CFR was low in the majority of nonischemic regions, a finding that may have important prognostic relevance. PET/CT fusion imaging could potentially influence planning for CABG and provide incremental prognostic information.</p>

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