Optimal gating compared to 3D and 4D PET reconstruction for characterization of lung tumours

Elmpt, Wouter van; Hamill, James; Jones, J.P.; Ruysscher, Dirk De; Lambin, Philippe; Öllers, Michel

doi:10.1007/s00259-010-1716-6

Cited by 113 publications

(95 citation statements)

References 34 publications

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“…Images were acquired using a Siemens Biograph 40 mCT PET/CT scanner with optimized, amplitude-based respiratory gating (HDÁChest) (12). The PET scanner has an extended axial field of view of 216 mm with 4 lutetium oxyorthosilicate detector rings.…”

Section: Image Acquisitionmentioning

confidence: 99%

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Comparison of a Free-Breathing CT and an Expiratory Breath-Hold CT with Regard to Spatial Alignment of Amplitude-Based Respiratory-Gated PET and CT Images

Vos

Grootjans

Meeuwis

et al. 2014

Journal of Nuclear Medicine Technology

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Respiratory motion during PET has a significant effect on the quantification of radiotracer uptake in PET images. Even when respiratory motion is considered using PET gating techniques, inaccuracies in standardized uptake values can be caused by inappropriate attenuation correction due to a spatial mismatch between PET and CT. In this study, the effect of breath-hold CT imaging on the spatial match between CT and amplitude-based respiratory-gated PET images is investigated. Methods: Wholebody 18 F-FDG PET/CT imaging was performed in 52 patients with 125 lung lesions. 18 F-FDG PET was performed using optimized, amplitude-based respiratory gating. For CT, 36 patients were randomly assigned to the free-breathing (FB) group and 16 to the restexpiratory breath-hold (BH) group. Spatial mismatch between the PET and CT images was quantified by measuring the distance between the centroids of PET and CT lesions and calculating the Jaccard similarity coefficient (JSC). Results: In the upper lobes, the average distance between the centroids of the PET and CT lesions was 4.7 ± 3.1 and 6.0 ± 3.0 mm for the FB and BH groups, respectively (P 5 0.11). For the middle and lower lobes, the distances were 5.8 ± 4.3 and 5.1 ± 2.9 mm (P 5 0.70), respectively, and for the central region 4.8 ± 4.6 and 5.6 ± 2.0 mm (P 5 0.24), respectively. The JSC for the upper lobes was 0.28 ± 0.17 and 0.28 ± 0.19, for the FB and the BH group, respectively (P 5 0.83). For the middle and lower lobes, the JSC was 0.22 ± 0.16 and 0.28 ± 0.18 (P 5 0.20), respectively, and for the central region 0.39 ± 0.17 and 0.13 ± 0.04 (P 5 0.04), respectively. Conclusion: Providing breathing instructions to the patients during the CT acquisition did not improve the spatial alignment between the respiratory-gated PET images and the CT images. The difficulty experienced in using this clinical protocol, such as patient compliance and operator dependence, emphasizes the need for other strategies.Key Words: amplitude-based optimal respiratory gating; lung tumors; standardized uptake value; breath hold CT; spatial alignment PET combined with CT is an essential multimodality molecular imaging method for accurate staging and diagnosis of a variety of diseases, particularly in oncology (1,2). The advantage of combined PET/CT imaging is that it provides both anatomic and molecular information on the patient, improving detection, localization, and characterization of disease (2). Furthermore, the CT scan can be used for PET attenuation correction. Quantitative indices in PET, such as the standardized uptake value (SUV) (3), metabolic volume, and total lesion glycolysis (4,5), can be used to diagnose the disease, to provide prognostic and predictive information, and to optimize radiotherapy planning. Furthermore, it has been established that molecular imaging with PET is valuable in the early assessment of therapy response of several tumor types (6-9).During PET acquisition, patients are instructed to breathe freely because of the relatively long image acquisition times. As a cons...

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Section: Image Acquisitionmentioning

confidence: 99%

“…As a consequence, respiratory motion can result in significant blurring of structures within the thorax and upper abdomen, reducing quantitative accuracy of radiotracer uptake and accurate volume definition in PET images (10)(11)(12)(13). Different strategies have been developed in an attempt to correct PET images for respiratory motion.…”

mentioning

confidence: 99%

Comparison of a Free-Breathing CT and an Expiratory Breath-Hold CT with Regard to Spatial Alignment of Amplitude-Based Respiratory-Gated PET and CT Images

Vos

Grootjans

Meeuwis

et al. 2014

Journal of Nuclear Medicine Technology

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“…In the thoracic-abdominal region, respiratory motion is a major challenge for PET imaging (1)(2)(3). Correction methodologies involve the use of gated frames that are of low signal-to-noise ratio since each frame contains only part of the counts available in a motion-averaged PET study (4)(5)(6).…”

mentioning

confidence: 99%

Reconstruction-Incorporated Respiratory Motion Correction in Clinical Simultaneous PET/MR Imaging for Oncology Applications

Fayad

Schmidt²,

Wuerslin³

et al. 2015

J Nucl Med

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Simultaneous PET and MR imaging is a promising new technique allowing the fusion of functional (PET) and anatomic/functional (MR) information. In the thoracic-abdominal regions, respiratory motion is a major challenge leading to reduced quantitative and qualitative image accuracy. Correction methodologies include the use of gated frames that lead to low signal-to-noise ratio considering the associated low statistics. More advanced correction approaches, previously developed for PET/CT imaging, consist of either registering all the reconstructed gated frames to the reference frame or incorporating motion parameters into the iterative reconstruction process to produce a single motioncompensated PET image. The goal of this work was to compare these two-previously implemented in PET/CT-correction approaches within the context of PET/MR motion correction for oncology applications using clinical 4-dimensional PET/MR acquisitions. Two different correction approaches were evaluated comparing the incorporation of elastic transformations extracted from 4-dimensional MR imaging datasets during PET list-mode image reconstruction to a postreconstruction imagebased approach. Methods: Eleven patient datasets acquired on a PET/MR system were used. T1-weighted 4D MR images were registered to the end-expiration image using a nonrigid B-spline registration algorithm to derive deformation matrices accounting for respiratory motion. The derived matrices were subsequently incorporated within a PET image reconstruction of the original emission list-mode data (reconstruction space [RS] method). The corrected images were compared with those produced by applying the deformation matrices in the image space (IS method) followed by summing the realigned gated frames, as well as with uncorrected motion-averaged images. Results: Both correction techniques led to significant improvement in accounting for respiratory motion artifacts when compared with uncorrected motionaveraged images. These improvements included signal-to-noise ratio (mean increase of 28.0% and 24.2% for the RS and IS methods, respectively), lesion size (reduction of 60.4% and 47.9%, respectively), lesion contrast (increase of 70.1% and 57.2%, respectively), and lesion position (changes of 60.9% and 46.7%, respectively). Conclusion: Our results demonstrate significant respiratory motion compensation using both methods, with superior results from a 4D PET RS approach.

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“…The Biograph 64 mCT Flow PET/CT scanner (Siemens Healthcare) was used at UT. PET images from both scanners were acquired using an optimized, amplitude-based respiratory gating algorithm (HDÁChest) integrated in the PET/CT software (11,17). For the Biograph 40 mCT, the respiratory gating was performed on bed positions covering the thorax and upper abdomen.…”

Section: Pet Acquisition and Respiratory Gatingmentioning

confidence: 99%

“…Van Elmpt et al suggested that respiration-triggered CT could be used for this purpose (17). In the present study, we pursue the triggered CT concept, comparing results based on spiral and triggered CT for improving spatial matching of CT with amplitude-based optimal respiration-gated PET imaging.…”

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confidence: 99%

Improving the Spatial Alignment in PET/CT Using Amplitude-Based Respiration-Gated PET and Respiration-Triggered CT

et al. 2015

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Respiratory motion during PET can cause inaccuracies in the quantification of radiotracer uptake, which negatively affects PETguided radiotherapy planning. Quantitative accuracy can be improved by respiratory gating. However, additional miscalculation of standardized uptake value (SUV) in PET images can be caused by inappropriate attenuation correction due to a spatial mismatch between gated PET and CT. In this study, the effect of respirationtriggered CT on the spatial match between CT and amplitude-based respiration-gated PET images is investigated. Methods: 18 F-FDG PET/CT was performed in 38 patients. Images were acquired on 2 PET/CT scanners, one without and one with continuous bed motion during PET acquisition. The amplitude limits of the amplitude-based respiration-gated PET were used for the respiration-triggered sequential low-dose CT. Both standard (spiral) and triggered CT scans were used to reconstruct the PET data. Spatial mismatch was quantified using the position difference between the lung-liver boundary in PET and CT images, the distance between PET and CT lung lesions' centroids, and the amount of overlap of lesions indicated by the Jaccard similarity coefficient. Furthermore, the effect of attenuation correction was quantified by measuring SUVs in lung lesions. Results: For triggered CT, the average distance between the lung-liver boundary in PET and CT was significantly reduced (4.5 ± 6.7 mm) when compared with standard CT (9.2 ± 8.1 mm) (P , 0.001). The mean distance between the lesions' centroids in PET and CT images was 6.3 ± 4.0 and 5.6 ± 4.2 mm (P 5 0.424), for the standard and triggered CT, respectively. Similarly, the Jaccard similarity coefficient was 0.30 ± 0.21 and 0.32 ± 0.20 (P 5 0.609) for standard and triggered CT, respectively. For 6 lesions, there was no overlap of PET and CT when the standard CT was used; compared with the triggered CT, these lesions showed (partial) overlap. The maximum and mean SUV increase of the PET/CT compared with the PET/triggered CT was 5.7% ± 11.2% (P , 0.001) and 6.1% ± 10.2% (P 5 0.001), respectively. Conclusion: Amplitude-based respiration-gated PET in combination with respiration-triggered CT resulted in a significantly improved match in the area of the liver dome and a significantly higher SUV for lung lesions. However, lesions in the lungs did not show a consistent improvement in spatial match.

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Optimal gating compared to 3D and 4D PET reconstruction for characterization of lung tumours

Cited by 113 publications

References 34 publications

Comparison of a Free-Breathing CT and an Expiratory Breath-Hold CT with Regard to Spatial Alignment of Amplitude-Based Respiratory-Gated PET and CT Images

Comparison of a Free-Breathing CT and an Expiratory Breath-Hold CT with Regard to Spatial Alignment of Amplitude-Based Respiratory-Gated PET and CT Images

Reconstruction-Incorporated Respiratory Motion Correction in Clinical Simultaneous PET/MR Imaging for Oncology Applications

Improving the Spatial Alignment in PET/CT Using Amplitude-Based Respiration-Gated PET and Respiration-Triggered CT

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