Importance of attenuation correction in PET/MR image quantification: Methods and applications

Abstract Recent emerging hybrid technology of positron emission tomography/magnetic resonance (PET/MR) imaging has generated a great need for an accurate MR image-based PET attenuation correction. MR image segmentation, as a robust and simple method for PET attenuation correction, has been clinically adopted in commercial PET/MR scanners. The general approach in this method is to segment the MR image into different tissue types, each assigned an attenuation constant as in an X-ray CT image. Machine learning techniques such as clustering, classification and deep networks are extensively used for brain MR image segmentation. However, only limited work has been reported on using deep learning in brain PET attenuation correction. In addition, there is a lack of clinical evaluation of machine learning methods in this application. The aim of this review is to study the use of machine learning methods for MR image segmentation and its application in attenuation correction for PET brain imaging. Furthermore, challenges and future opportunities in MR image-based PET attenuation correction are discussed.

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Simplified approach to MR image quantification of the rheumatoid wrist: a pilot study

Skeletal Radiology ◽

10.1007/s00256-010-0935-z ◽

2010 ◽

Vol 40 (1) ◽

pp. 65-74 ◽

Cited By ~ 6

Author(s):

Tamotsu Kamishima ◽

Kazuhide Tanimura ◽

Yuko Aoki ◽

Naoki Kosaka ◽

Masato Shimizu ◽

...

Keyword(s):

Pilot Study ◽

Image Quantification ◽

Mr Image ◽

Simplified Approach ◽

Rheumatoid Wrist

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MR Image Reference Maps Out RA Pathology

Internal Medicine News ◽

10.1016/s1097-8690(05)70166-9 ◽

2005 ◽

Vol 38 (6) ◽

pp. 26-27

Author(s):

KERRI WACHTER

Keyword(s):

Mr Image

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Myocardial perfusion scintigraphy in Germany

Nuklearmedizin ◽

10.1055/s-0037-1621023 ◽

2007 ◽

Vol 46 (02) ◽

pp. 49-55 ◽

Cited By ~ 7

Author(s):

W. Burchert ◽

F. M. Bengel ◽

R. Zimmermann ◽

J. vom Dahl ◽

W. Schäfer ◽

...

Keyword(s):

Nuclear Medicine ◽

Myocardial Perfusion ◽

Attenuation Correction ◽

Working Group ◽

Primary Care Physicians ◽

Gated Spect ◽

Myocardial Perfusion Scintigraphy ◽

German Society ◽

University Hospitals ◽

Perfusion Scintigraphy

SummaryThe working group Cardiovascular Nuclear Medicine of the German Society of Nuclear Medicine (DGN), in cooperation with the working group Nuclear Cardiology of the German Cardiac Society (DGK), decided to conduct a national survey on myocardial perfusion scintigraphy (MPS). Method: A questionnaire to evaluate MPS for the year 2005 was sent. Results: 346 completed questionnaires had been returned (213 private practices, 99 hospitals and 33 university hospitals). MPS of 112 707 patients were reported with 110 747 stress and 95 878 rest studies. The majority (>75%) was performed with 99mTc-MIBI or tetrofosmin. 201Tl stress-redistribution was used in 22 637 patients (20%). The types of stress were exercise in 78%, vasodilation with adenosine or dipyridamol in 21% and dobutamine in 1%. 99.97% of all MPS were SPECT studies. Gated SPECT was performed in 36% of the stress and in 32% of the rest studies. An attenuation correction was used in 21%. 29 institutions (8%) performed gated SPECT (stress and rest) and attenuation correction. 47% of all MPS were requested by ambulatory care cardiologists, 17% by internists, 12% by primary care physicians, 21% by hospital departments and 2% by others. Conclusion: In Germany, MPS is predominantly performed with 99mTc-perfusion agents. The common type of stress is ergometry. Gated SPECT and attenuation correction do not yet represent standards of MPS practice in Germany, which indicates some potential of optimization.

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F-18-FDG Positron Imaging in Oncological Patients: Gamma Camera Coincidence Detection versus Dedicated PET

Nuklearmedizin ◽

10.1055/s-0038-1632201 ◽

1999 ◽

Vol 38 (04) ◽

pp. 108-114 ◽

Cited By ~ 3

Author(s):

H.-J. Kaiser ◽

U. Cremerius ◽

O. Sabri ◽

M. Schreckenberger ◽

P. Reinartz ◽

...

Keyword(s):

Attenuation Correction ◽

Spatial Resolution ◽

Gamma Camera ◽

Lesion Detection ◽

Coincidence Detection ◽

System Sensitivity ◽

Oncological Patients ◽

Phantom Studies ◽

Pet System ◽

Dedicated Pet

Summary Aim of the present study was to investigate the feasibility of 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) imaging in oncological patients with a dual head gamma camera modified for coincidence detection (MCD). Methods: Phantom studies were done to determine lesion detection at various lesion-to-background ratios, system sensitivity and spatial resolution. Thirty-two patients with suspected or known malignant disease were first studied with a dedicated full-ring PET system (DPET) applying measured attenuation correction and subsequently with an MCD system without attenuation correction. MCD images were first interpreted without knowledge of the DPET findings. In a second reading, MCD and DPET were evaluated simultaneously. Results: The phantom studies revealed a comparable spatial resolution for DPET and MCD (5.9 × 6.3 × 4.2 mm vs. 5.9 × 6.5 × 6.0 mm). System sensitivity of MCD was less compared to DPET (91 cps/Bq/ml/cmF0V vs. 231 cps/ Bq/ml/cmFOv). At a lesion-to-background ratio of 4:1, DPET depicted a minimal phantom lesion of 1.0 cm in diameter, MCD a minimal lesion of 1.6 cm. With DPET, a total of 91 lesions in 27 patients were classified as malignant. MCD without knowledge of DPET results revealed increased FDG uptake in all patients with positive DPET findings. MCD detected 72 out of 91 DPET lesions (79.1 %). With knowledge of the DPET findings, 11 additional lesions were detected (+12%). MCD missed lesions in six patients with relevance for staging in two patients. All lesions with a diameter above 18 mm were detected. Conclusion: MCD FDG imaging yielded results comparable to dedicated PET in most patients. However, a considerable number of small lesions clearly detectable with DPET were not detected by MCD alone. Therefore, MCD cannot yet replace dedicated PET in all oncological FDG studies. Further technical refinement of this new method is needed to improve image quality (e.g. attenuation correction).

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