Magnetic Resonance–Based Attenuation Correction for PET/MR Hybrid Imaging Using Continuous Valued Attenuation Maps

@article{Navalpakkam2013MagneticRA,
  title={Magnetic Resonance–Based Attenuation Correction for PET/MR Hybrid Imaging Using Continuous Valued Attenuation Maps},
  author={Bharath K. Navalpakkam and Harald Braun and Torsten Kuwert and Harald Quick},
  journal={Investigative Radiology},
  year={2013},
  volume={48},
  pages={323–332}
}
ObjectivesAttenuation correction of positron emission tomographic (PET) data is critical in providing accurate and quantitative PET volumes. Deriving an attenuation map (&mgr;-map) from magnetic resonance (MR) volumes is a challenge in PET/MR hybrid imaging. The difficulty lies in differentiating cortical bone from air from standard MR sequences because both these classes yield little to no MR signal and thus shows no distinguishable information. The objective of this contribution is 2-fold: (1… 
MR-Based Attenuation Correction Using Ultrashort-Echo-Time Pulse Sequences in Dementia Patients
TLDR
A fully automatic method to estimate the μ map, including bone tissue using only MR information, is presented and shows significantly reduced errors in quantification, and therefore delivered more accurate PET image quantification for an improved diagnostic workup in dementia patients.
Attenuation Correction Synthesis for Hybrid PET-MR Scanners: Application to Brain Studies
TLDR
The aim of the proposed work is to improve attenuation correction for PET/MR scanners by generating synthetic CTs and attenuation maps through a multi-atlas information propagation scheme, locally matching the MRI-derived patient's morphology to a database of MRI/CT pairs, using a local image similarity measure.
Impact of MR-Based Attenuation Correction on Neurologic PET Studies
TLDR
MR-based attenuation correction led to underestimation of PET activity for most parts of the brain, with a small overestimation for deep brain regions, and SUVR measurements obtained from the 2 attenuation-correction methods were strongly correlated.
Evaluation of zero-echo-time attenuation correction for integrated PET/MR brain imaging—comparison to head atlas and 68Ge-transmission-based attenuation correction
TLDR
ZTE-AC shows to be a more robust technique than atlas-AC in terms of both intra- and inter-patient variability, but bias was similar for both methods.
PET/MR brain imaging: evaluation of clinical UTE-based attenuation correction
TLDR
The results indicate that the performance of the UTE method as implemented in VB20P is close to the theoretical maximum of such an MRAC method in the brain, while it does not perform satisfactorily in the neck or face/nasal area.
Simultaneous carotid PET/MR: feasibility and improvement of magnetic resonance-based attenuation correction
TLDR
Techniques to improve carotid vascular PET/MR quantification by adding a bone tissue compartment to MRAC maps and deriving continuous Dixon-based MRAC (MRACCD) maps are demonstrated.
Tissue Probability-Based Attenuation Correction for Brain PET/MR by Using SPM8
TLDR
A tissue-probability based attenuation correction (TPB-AC) is proposed, which employs the commonly available neurological toolbox SPM8 to derive a subject-specific MR-based μ-map by segmentation of T1-weighted MR images, showing improvement of visual quality and quantitative accuracy of positron emission tomography (PET) images when TPB- AC μ- map is used in PET/MR image reconstruction.
Segmentation-Based Attenuation Correction in Positron Emission Tomography/Magnetic Resonance: Erroneous Tissue Identification and Its Impact on Positron Emission Tomography Interpretation
TLDR
Attenuation map artifacts that occur in a considerable percentage of PET/MR data sets have the potential to falsify PET quantification and visual PET interpretation and no change in diagnosis would have been caused by &mgr;-map artifacts.
Accurate hybrid template–based and MR-based attenuation correction using UTE images for simultaneous PET/MR brain imaging applications
TLDR
A novel attenuation correction method for PET data reconstruction is proposed that shows improvements in the quantitative accuracy of the reconstructed PET images compared to other state-of-the-art AC methods for simultaneous PET/MR scanners.
Region specific optimization of continuous linear attenuation coefficients based on UTE (RESOLUTE): application to PET/MR brain imaging
TLDR
The proposed MR-AC method with patient specific continuous-valued linear attenuation coefficients in bone is clinically feasible, reducing both the global and local errors on the reconstructed PET images, as well as limiting the number and extent of the outliers.
...
...

References

SHOWING 1-10 OF 31 REFERENCES
Automatic, three-segment, MR-based attenuation correction for whole-body PET/MR data
TLDR
A fully automated approach that uses a dedicated T1-weighted MR sequence in combination with a customized image processing technique to derive attenuation maps for whole-body PET and offers similar correction accuracy as offered by segmented CT.
MRI-Based Attenuation Correction for Hybrid PET/MRI Systems: A 4-Class Tissue Segmentation Technique Using a Combined Ultrashort-Echo-Time/Dixon MRI Sequence
TLDR
The UTE triple-echo (UTILE) MRI sequence enables the generation of MRI-based 4-class μ-maps without anatomic priors, yielding results more similar to CT-based results than can be obtained with 3-class segmentation only.
MRI-Based Attenuation Correction for PET/MRI: A Novel Approach Combining Pattern Recognition and Atlas Registration
TLDR
A combination of local pattern recognition and atlas registration is used to predict pseudo-CT images from a given MR image, which allows reliable MRI-based attenuation correction for human brain scans and enables PET quantification with a mean error of 3.2%.
Quantitative accuracy of attenuation correction in the Philips Ingenuity TF whole-body PET/MR system: a direct comparison with transmission-based attenuation correction
TLDR
The MR-based attenuation correction implemented on the Philips Ingenuity PET/MR provides reasonable quantitative accuracy, and deviations from TRAC-based results are small, but due to interindividual variability of the segmentation quality, deviations of more than 20 %  can occur.
Image artifacts from MR-based attenuation correction in clinical, whole-body PET/MRI
  • S. KellerS. Holm T. Beyer
  • Medicine, Physics
    Magnetic Resonance Materials in Physics, Biology and Medicine
  • 2012
TLDR
A clinical adoption of integrated PET/MRI should entail the joint image display and interpretation of MR data, MR-based attenuation maps and uncorrected plus attenuation-corrected PET images in order to recognize potential pitfalls from MR-AC and to ensure clinically accurate image interpretation.
Toward Implementing an MRI-Based PET Attenuation-Correction Method for Neurologic Studies on the MR-PET Brain Prototype
TLDR
The segmented CT AC method was established as the silver standard for the segmented MRI-based AC method and could be used for quantitative neurologic MR-PET studies.
Diffusion Tensor Imaging in a Human PET/MR Hybrid System
TLDR
Diffusion tensor imaging may be combined with simultaneous PET data acquisition, offering additional important morphologic and functional information for treatment planning in patients with brain tumors.
Attenuation correction for a combined 3D PET/CT scanner.
TLDR
The proof of principle of CT-based attenuation correction of 3D positron emission tomography (PET) data is demonstrated by using scans of bone and soft tissue equivalent phantoms and scans of humans to conclude that using CT information is a feasible way to obtain attenuation Correction factors for 3D PET.
The effect of errors in segmented attenuation maps on PET quantification.
TLDR
When using a segmented attenuation map, at least five different tissue types should be considered: cortical bone, spongeous bone, soft tissue, lung, and air, and the interpatient variability of lung attenuation coefficients should be taken into account.
Comparison of lesion detection and quantitation of tracer uptake between PET from a simultaneously acquiring whole-body PET/MR hybrid scanner and PET from PET/CT
TLDR
PET/MR showed equivalent performance in terms of qualitative lesion detection to PET/CT and quantitation of tracer uptake, and a more detailed study of the quantitative accuracy of PETMR and the factors governing it is needed to ultimately assess its accuracy in measuring tissue tracer concentrations.
...
...