ライフサイエンスコーパス: attenuation correction

1 es were performed using a PET/CT scanner (CT attenuation correction).

2 enuation correction with the ground-truth CT attenuation correction.

3 anche photodiodes and the need for MRI-based attenuation correction.

4 n was significantly lower than that with the attenuation correction.

5 using filtered backprojection with CT-based attenuation correction.

6 , a transmission scan was first acquired for attenuation correction.

7 (ECG)-gated CT scan that is used to perform attenuation correction.

8 of myocardial perfusion SPECT improves with attenuation correction.

9 acquisition parameters that provide adequate attenuation correction.

10 hich offer limited accuracy compared with CT attenuation correction.

11 use of filtered backprojection with CT-based attenuation correction.

12 CT scan provides the attenuation map for PET attenuation correction.

13 ity-maximum image of cine CT for cardiac PET attenuation correction.

14 l respiration-induced misalignment errors in attenuation correction.

15 ntation of CT-based transmission imaging for attenuation correction.

16 a cardiac insert, using a SPECT system with attenuation correction.

17 PET scanner using transmission source-based attenuation correction.

18 n a PET/CT scanner, using the CT portion for attenuation correction.

19 ontrast agent, and the CT data were used for attenuation correction.

20 e chosen method for image reconstruction and attenuation correction.

21 ed methods for both image reconstruction and attenuation correction.

22 T-based attenuation correction (CTAC) to PET attenuation correction.

23 sing iterative reconstruction with segmented attenuation correction.

24 etween images reconstructed with and without attenuation correction.

25 are into PET energy during the process of CT attenuation correction.

26 e appearance of images reconstructed without attenuation correction.

27 pear as photopenic regions in images without attenuation correction.

28 ke disappear in images reconstructed without attenuation correction.

29 at obtained with two-dimensional FBP without attenuation correction.

30 e maximum a posteriori (MAP) algorithm using attenuation correction.

31 with images with two-dimensional FBP without attenuation correction.

32 agent was used for anatomic localization and attenuation correction.

33 mization algorithm that included scatter and attenuation correction.

34 tterAC versus nonuniform, transmission-based attenuation correction.

35 ocessed and applied to the emission data for attenuation correction.

36 l-to-noise ratio generally was improved with attenuation correction.

37 ed variation of 20%-25% in the image with no attenuation correction.

38 ructed using ML, with and without nonuniform attenuation correction.

39 ompared using nonuniform, uniform or even no attenuation correction.

40 tative SPECT images achieved with nonuniform attenuation correction.

41 e myocardium was improved by object-specific attenuation correction.

42 mined for 180 degrees reconstruction without attenuation correction.

43 This bias improved after attenuation correction.

44 field of view with CT from the GeminiTF for attenuation correction.

45 atlas methods by reducing PET error owing to attenuation correction.

46 ient anatomic accuracy for, for example, PET attenuation correction.

47 did not necessitate additional radiation for attenuation correction.

48 ation of bone lesions despite differences in attenuation correction.

49 ollowed by PET/MR imaging with 2-point Dixon attenuation correction.

50 Quantitative PET imaging relies on accurate attenuation correction.

51 he uncertainties associated with scatter and attenuation corrections.

52 sional filtered backprojection (FBP) without attenuation correction (a common clinical protocol), thr

53 es for magnetic resonance (MR) imaging-based attenuation correction (AC) (termed deep MRAC) in brain

54 tional filtered backprojection (FBP) without attenuation correction (AC) and those reconstructed usin

55 We present an approach for head MR-based attenuation correction (AC) based on the Statistical Par

56 CT-based attenuation correction (AC) for myocardial perfusion PET

57 Attenuation correction (AC) for myocardial perfusion SPE

58 e aim of this study was to determine whether attenuation correction (AC) improved the diagnostic perf

59 Metalic implants may affect attenuation correction (AC) in PET/MR imaging.

60 Attenuation correction (AC) is a critical requirement fo

61 Accurate gamma-photon attenuation correction (AC) is essential for quantitativ

62 In routine whole-body PET/MR hybrid imaging, attenuation correction (AC) is usually performed by segm

63 this study was to explore the feasibility of attenuation correction (AC) of myocardial perfusion imag

64 Attenuation correction (AC) of PET images with helical C

65 study was performed to assess the effects of attenuation correction (AC) on overall image uniformity

66 mages were reconstructed with four different attenuation correction (AC) PET with patient CT-based AC

67 ECT reconstructions have been compared using attenuation correction (AC) with various methods for est

68 patients undergoing stress-only imaging with attenuation correction (AC) would validate the safety of

69 es do not correlate directly with PET photon attenuation correction (AC), and inaccurate radiotracer

70 ies when CT instead of germanium is used for attenuation correction (AC).

71 ruction than with FBP, both with and without attenuation correction (AC).

72 -subset expectation maximization (OSEM) with attenuation correction (AC); OSEM with AC and scatter co

73 The aim of this study was to compare attenuation-correction (AC) approaches for PET/MRI in cl

74 o be considered for implementing an accurate attenuation-correction (AC) method in a combined MR-PET

75 An attenuation correction algorithm was used.

76 change significantly after application of an attenuation correction algorithm.

77 d without application of the iterative Chang attenuation correction algorithm.

78 accuracy and the precision of SPECT images; attenuation correction algorithms correct the bias but c

79 Improved attenuation-correction algorithms and a PET/MR-specific

80 Present attenuation-correction algorithms in whole-body PET/MRI

81 Nonuniform attenuation correction allowed a moderate improvement in

82 nstruction, scatter correction, and CT-based attenuation correction allows quantification of (99m)Tc

83 an integrated x-ray transmission system for attenuation correction, anatomic mapping, and image fusi

84 quence (Dixon) used for MR imaging-based PET attenuation correction and a high-resolution MAVRIC sequ

85 Measured attenuation correction and a standard reconstruction pro

86 rrection, two-dimensional FBP with segmented attenuation correction and a two-dimensional iterative m

87 ause it is not associated with radiation for attenuation correction and allows more accurate dosimetr

88 h-hold examination (VIBE) Dixon sequence for attenuation correction and an unenhanced coronal T1-weig

89 Unenhanced CT scans were acquired for attenuation correction and anatomic coregistration.

90 The integrated CT can be used for attenuation correction and anatomic localization.

91 erpolated breath-hold examination) Dixon for attenuation correction and contrast-enhanced VIBE pulse

92 multaneous PET/MR scanner, using MR for both attenuation correction and depiction of lesion location.

93 to February 2005 has advanced the concept of attenuation correction and electrocardiographic gating i

94 Rb-82 PET or technetium-99m SPECT with both attenuation correction and electrocardiography-gating we

95 data and images reconstructed with CT-based attenuation correction and energy window-based scatter c

96 sisting of stress/rest scans with or without attenuation correction and gated stress/rest images (1,9

97 if the unenhanced CT portion, performed for attenuation correction and lesion localization, provides

98 CT is still frequently used only for attenuation correction and lesion localization.

99 times (3-5 min/field of view) and for CT for attenuation correction and localization with a weight-ba

100 sing (18)F-FDG and a PET/CT scanner (with CT attenuation correction and ordered-subsets expectation m

101 of using 4D NAC PET images for accurate PET attenuation correction and respiratory motion correction

102 of using 4D NAC PET images for accurate PET attenuation correction and respiratory motion correction

103 thod was compared with conventional CT-based attenuation correction and the 3-segment, MR-based atten

104 The simplified narrow-beam attenuation correction and the effective (broad-beam) co

105 ted for attenuation using reference CT-based attenuation correction and the resulting 4-class MRAC ma

106 activity measured with PET/CT when using CT attenuation correction and to report our initial experie

107 cquired transmission data permits nonuniform attenuation correction and when incorporating scatter co

108 SPECT data were reconstructed with CT-based attenuation correction and with full as well as 50% and

109 have shown that, by applying object-specific attenuation corrections and suitable partial-volume corr

110 dium-82 cardiac PET-CT (CT was only used for attenuation correction) and coronary angiography within

111 onal resolution recovery (OSEM-3D), CT-based attenuation correction, and scatter correction.

112 were reconstructed with and without CT-based attenuation correction, and the reconstructed SPECT imag

113 Despite different attenuation correction approaches, tracer uptake in lesi

114 Cervical spine reconstructions without attenuation correction are difficult to interpret, becau

115 The advantages of attenuation correction are quantitative accuracy, wherea

116 ults show that TOF PET can remarkably reduce attenuation correction artifacts and quantification erro

117 luate CT image noise and the adequacy of PET attenuation correction as a function of CT acquisition p

118 st differences were calculated with CT-based attenuation correction as a reference.

119 In comparison to nonuniform attenuation correction as the gold standard, uniform att

120 he patient-dependent accuracy of atlas-based attenuation correction (ATAC) for brain positron emissio

121 cted (UC) ZTAC (ZTACUC) and a CT atlas-based attenuation correction (ATAC).

122 ation correction and the 3-segment, MR-based attenuation correction available on the TOF PET/MR imagi

123 LROC curves [A(z,LROC)] 0.13) and segmented attenuation correction (average Az 0.59; average Az,LROC

124 9) compared with two-dimensional FBP without attenuation correction (average Az 0.79; average A(z,LRO

125 Attenuation correction based on asymmetric fanbeam TCT s

126 The results of attenuation correction based on TCTs as short as 1 min w

127 tion correction (NC), (b) conventional Chang attenuation correction based on the interactive determin

128 Explicit attenuation correction based on the transmission scan or

129 For pediatric patients, adequate attenuation correction can be obtained with very-low-dos

130 Although a measured attenuation correction can potentially provide an exact

131 MR-based attenuation correction causes biases in quantitative mea

132 T images and reduces error in pelvic PET/MRI attenuation correction compared with standard methods.

133 ntial whole-body (18)F-FDG PET with CT-based attenuation correction, contrast-enhanced (ce) CT, and c

134 First, a whole-body attenuation correction CT scan was obtained.

135 ts are an established limitation of CT-based attenuation correction (CT-AC) in PET/CT.

136 rtery calcium (CAC) from computed tomography attenuation correction (CTAC) scans performed for hybrid

137 TACUC, ZTACSEC, ATAC, and reference CT-based attenuation correction (CTAC) to PET attenuation correct

138 results due to misregistration of PET and CT attenuation correction data-the frequency, cause, and co

139 in PET images can be caused by inappropriate attenuation correction due to a spatial mismatch between

140 T scans performed for anatomic reference and attenuation correction during PET/CT.

141 r-correction error was more significant than attenuation-correction error.

142 , allowed the relative impact of scatter and attenuation-correction errors to be determined.

143 e of respiratory motion causes errors in the attenuation correction factors and artifacts in the atte

144 of errors within the brain was obtained from attenuation correction factors computed from uniform and

145 CT images can be used to generate noiseless attenuation correction factors for the PET emission data

146 troduction of errors due to bad estimates of attenuation correction factors resulting from smoothing

147 Attenuation correction factors were calculated from both

148 ficients to the head model for generation of attenuation correction factors.

149 n maximization (OSEM) without any scatter or attenuation correction (FBP-NATS and OSEM-NATS) or corre

150 hod is described using a (153)Gd-line source attenuation correction for body outline.

151 Further developments in attenuation correction for perfusion imaging and phase-c

152 The literature has validated the concept of attenuation correction for the accurate assessment of at

153 a technique that uses downscatter to provide attenuation correction for these acquisitions and compar

154 In the phantom study, the attenuation correction from helical CT caused a major ar

155 The attenuation correction from the average and from the int

156 the heterogeneous brain phantom, the uniform attenuation correction had errors of 2%-6.5% for regions

157 In PET, transmission scanning for attenuation correction has most commonly been performed

158 ty and attenuation (MLAA) for emission-based attenuation correction has regained attention since the

159 ECG gating and attenuation correction help increase specificity and acc

160 ancers underwent PET/CT with low-dose CT for attenuation correction immediately followed by PET/MR im

161 sed algorithm could improve MR imaging-based attenuation correction in critical areas, when standard

162 odifying Dixon-based MR imaging datasets for attenuation correction in hybrid PET/MR imaging with a m

163 Attenuation correction in hybrid PET/MR scanners is stil

164 serves as a potential solution for accurate attenuation correction in hybrid PET/MR systems.

165 Algorithms for attenuation correction in hybrid SPECT/CT systems have t

166 Nuclear Medicine have recognized the role of attenuation correction in increasing the diagnostic accu

167 metallic implants, to be used for whole-body attenuation correction in integrated PET/MR scanners.

168 sessed the accuracy of 4 methods of MR-based attenuation correction in lesions within soft tissue, bo

169 Apart from drawbacks of MR-based PET attenuation correction in osseous structures and lungs,

170 of uptake on PET images depends on accurate attenuation correction in reconstruction.

171 Thus, the accuracy of MR-based attenuation correction in simultaneously acquired data c

172 The addition of attenuation correction in the presence of extracardiac a

173 mages, confirming the robustness of CT-based attenuation correction in the presence of metallic artif

174 nt a novel technique for accurate whole-body attenuation correction in the presence of metallic endop

175 onsiderable debate about the desirability of attenuation correction in whole-body PET oncology imagin

176 In our series of 13 SLK recipients, attenuation correction increased the measured renal func

177 ifacts do not propagate through the CT-based attenuation correction into the PET images, confirming t

178 dings and may propagate through the CT-based attenuation correction into the PET images.

179 correction in critical areas, when standard attenuation correction is hampered by metal artifacts, u

180 MR-based attenuation correction is instrumental for integrated PE

181 Attenuation correction is recommended to optimize the pe

182 MR-based attenuation correction led to underestimation of PET act

183 filtered backprojection (FBP) with measured attenuation correction (MAC) or iterative reconstruction

184 otocols: (a). 3 initial consecutive measured attenuation correction (MAC) scans, followed by resting

185 obtained with the ultrashort-echo-time-based attenuation correction maps currently used in the scanne

186 volume, thus allowing us to create accurate attenuation correction maps.

187 This review addresses how CT-based attenuation correction may affect the quantitative analy

188 Therefore, STE with nonuniform attenuation correction may also result in reconstruction

189 Even though images without attenuation correction may be desired, these results sug

190 attenuation-corrected images, images without attenuation correction may have locally enhanced contras

191 However, using pure parametric maps for attenuation correction may lead to bias close to certain

192 ted PET/MR instrumentation, such as MR-based attenuation correction, may particularly affect brain im

193 We have developed an automated attenuation correction method that compensates for subje

194 The transmission-based attenuation correction method was compared with conventi

195 hod and the reference standard continuous CT attenuation correction method.

196 Current MR-based attenuation correction methods for body PET use a fat an

197 This paper reviews recent developments in attenuation correction methods for cardiac SPECT perfusi

198 A scatter correction method and 2 attenuation correction methods, all applied to inhalatio

199 Because existing MR-based attenuation-correction methods were not designed specifi

200 SUVR measurements obtained from the 2 attenuation-correction methods were strongly correlated.

201 on as positive or negative regardless of the attenuation-correction methods.

202 ood expectation maximization with nonuniform attenuation correction (MLAC).

203 the reproducibility of standard, Dixon-based attenuation correction (MR-AC) in PET/MR imaging.

204 endent on reliable and reproducible MR-based attenuation correction (MR-AC).

205 sed algorithm with standard 4-class MR-based attenuation correction (MRAC) implemented on commercial

206 MR attenuation correction (MRAC) is generally conducted by

207 ification errors induced by MR imaging-based attenuation correction (MRAC) using simulation and clini

208 This method is compared with (a) no attenuation correction (NC), (b) conventional Chang atte

209 Stent position on attenuation-correction noncontrast CT and CTA was used t

210 e correction (frequency-distance principle), attenuation correction (nonuniform Chang correction or w

211 tudy were to develop a method for nonuniform attenuation correction of 123I emission brain images bas

212 r compensating for respiratory motion in the attenuation correction of cardiac PET studies.

213 CT images are intended for use in nonuniform attenuation correction of cardiac SPECT data.

214 col for acquiring a fast TCT can be used for attenuation correction of cardiac SPECT imaging.

215 the effects of patient motion on nonuniform attenuation correction of cardiac SPECT when the transmi

216 Attenuation correction of MR/PET images was segmentation

217 have been proposed in the past for MR-based attenuation correction of PET data, because of their abi

218 CT images were then used for attenuation correction of PET emission data.

219 going technologic challenges (e.g., accurate attenuation correction of PET images) but also to the co

220 ative ML-EM algorithm for reconstruction and attenuation correction of the coregistered SPECT images.

221 Fully corrected scans with attenuation correction of the entire chest were availabl

222 Attenuation correction of the filled NEMA phantom was pe

223 for both anatometabolic image formation and attenuation correction of the PET data.

224 n iterative algorithm for reconstruction and attenuation correction of the radionuclide image.

225 , the most prominent being this dataset used attenuation correction of the scintigraphic data.

226 expectation maximization reconstruction, CT attenuation correction) of patients with no known malign

227 a practical transmission scanning system for attenuation correction on a 2-head gamma camera coincide

228 tical approach to TCT imaging for nonuniform attenuation correction on a three-headed SPECT camera.

229 This method provides a way to perform attenuation correction on existing triple-head SPECT sys

230 enuation correction to approximately20% with attenuation correction only).

231 was achieved in the liver using scatter and attenuation corrections only, correction for finite spat

232 Use of segmented attenuation correction or three-dimensional acquisition

233 diopharmaceutical problems, lack of measured attenuation correction, or excessive head movement.

234 dicated this artifact was consistent with an attenuation-correction problem caused by misregistration

235 part be explained by inconsistencies in the attenuation-correction procedures.

236 nium-corrected emission PET images, CT-based attenuation correction produced radioactivity concentrat

237 The PET data were reconstructed using attenuation correction provided by both standard CT and

238 so acquired at the end of expiration for PET attenuation correction purposes.

239 s for diagnostic, anatomic localization, and attenuation correction purposes.

240 The CT scans acquired for PET attenuation-correction purposes were used as reference f

241 were compared with their reference CT-based attenuation correction reconstructions.

242 Attenuation correction reduced the artificially high app

243 Appropriate attenuation correction remains a challenge.

244 The necessity for PET attenuation correction required new methods based on MR

245 BEM uniformity (78% and 89% without and with attenuation correction, respectively [ideal value being

246 47 (87%) and 30 (56%) PHVs with and without attenuation correction, respectively, and the pattern wa

247 Attenuation correction results in many changes in the im

248 iterative reconstruction (IR) with segmented attenuation correction (SAC).

249 ure to compensate for subject motion between attenuation correction scans and emission scans preclude

250 In the present attenuation correction schemes, uncorrected MR susceptib

251 andardized uptake value relative to CT-based attenuation correction (SEG1, -2.6% +/- 5.8%; SEG2, -1.6

252 guration, STE reconstruction with nonuniform attenuation correction significantly improved image unif

253 phantom, STE reconstruction with nonuniform attenuation correction significantly improved uniformity

254 gate the impact of using a standard MR-based attenuation correction technique on the clinical and res

255 were demonstrated using the current MR-based attenuation-correction technique.

256 sitions and compare it with other recognized attenuation correction techniques.

257 equivalent to PET/CT despite differences in attenuation-correction techniques.

258 We have developed an automated method for attenuation correction that compensates for subject moti

259 ity was nondiagnostic in 81%; after CT-based attenuation correction this decreased to 55%.

260 th datasets to assess the impact of MR-based attenuation correction to absolute PET activity measurem

261 nd liver activity decreased from 90% without attenuation correction to approximately20% with attenuat

262 tudies should at least be reconstructed with attenuation correction to avoid missing regions of eleva

263 d differences between uniform and nonuniform attenuation correction to be in the range of 6.4%-16.0%

264 between CT and PET images, allowing accurate attenuation correction to be performed for respiration-s

265 cal protocol), three-dimensional FBP without attenuation correction, two-dimensional FBP with segment

266 ion followed by filtered backprojection with attenuation correction using a uniform attenuation map.

267 red the SUVs of the PET image obtained after attenuation correction using the patient-specific CT vol

268 e acquired with a PET/CT scanner, and (68)Ge attenuation correction was applied.

269 No attenuation correction was applied.

270 MR-based PET attenuation correction was compared with CT-derived atte

271 No attenuation correction was performed on these datasets.

272 n transmission reconstruction algorithm, and attenuation correction was performed using Chang's postp

273 ofile was generated for the case in which no attenuation correction was performed.

274 Furthermore, the effect of attenuation correction was quantified by measuring SUVs

275 uantified from SPECT images without CT-based attenuation correction was significantly lower than that

276 tric-mean quantification with background and attenuation correction was used for liver and lung dosim

277 striatum and background, whereas nonuniform attenuation correction was within 1%.

278 F-FDG PET (dual-head coincidence camera with attenuation correction) was performed before and after 1

279 ion Chang algorithm, modified for nonuniform attenuation correction, was used to further process the

280 ng phenomena in images reconstructed without attenuation correction, we performed a series of simulat

281 Using respiration-correlated CT for attenuation correction, we were able to quantitate the f

282 Images with and without attenuation correction were considered for interpretatio

283 The Dixon MRI sequences acquired for attenuation correction were found useful for anatomic al

284 Coregistration and attenuation correction were performed with CT.

285 using CT performed with 80 kVp and 5 mAs for attenuation correction were visually indistinguishable f

286 foci are visible in images with and without attenuation correction, whereas below the critical value

287 effects on ML reconstruction with nonuniform attenuation correction, which depends on the amount of e

288 82)Rb, a 16-slice PET/CT scanner, helical CT attenuation correction with breathing and also at end-ex

289 of 24 subjects were processed using measured attenuation correction with different levels of transmis

290 rror (RMSE) was used to compare the MR-based attenuation correction with the ground-truth CT attenuat

291 ification accuracy of 3 methods for MR-based attenuation correction without (SEGbase) and with bone p

292 ihood (ML) method incorporating a nonuniform attenuation correction would less likely be affected by

293 ajor challenge of zero-echo-time (ZTE)-based attenuation correction (ZTAC) is the misclassification o