Effect of Post-Reconstruction Gaussian Filtering on Image Quality and Myocardial Blood Flow Measurement with N-13 Ammonia PET

Document Type: Original Article

Authors

1 Department of Nuclear Medicine, Chonnam National University Hwasun Hospital, Hwasun-Gun, Jeollanamdo, South Korea

2 Department of Nuclear Medicine, Chonnam National University Hospital, Hwasun-Gun, Jeollanamdo, South Korea

3 Department of Cardiology, Chonnam National University Hospital, Hwasun-Gun, Jeollanamdo, South Korea

4 Department of Nuclear Medicine, Chonnam National University Hwasun Hospital, Hwasun-Gun, Jeollanamdo, South Korea

5 Korea Photonics Technology Institute, Gwangju City, South Korea

Abstract

Objective(s): In order to evaluate the effect of post-reconstruction Gaussian filtering on image quality and myocardial blood flow (MBF) measurement by dynamic N-13 ammonia positron emission tomography (PET), we compared various reconstruction and filtering methods with image characteristics.
Methods: Dynamic PET images of three patients with coronary artery disease (male-female
ratio of 2:1; age: 57, 53, and 76 years) were reconstructed, using filtered back projection (FBP) and ordered subset expectation maximization (OSEM) methods. OSEM reconstruction consisted of OSEM_2I, OSEM_4I, and OSEM_6I with 2, 4, and 6 iterations, respectively. The images, reconstructed and filtered by Gaussian filters of 5, 10, and 15 mm, were obtained, as well as non-filtered images. Visual analysis of image
quality (IQ) was performed using a 3-grade scoring system by 2 independent readers, blinded to the reconstruction and filtering methods of stress images. Then, signal-to-noise ratio (SNR) was calculated by noise and contrast recovery (CR). Stress and rest MBF and coronary flow reserve (CFR) were obtained for each method. IQ scores, stress and rest MBF, and CFR were compared between the methods, using Chi-square and Kruskal-Wallis tests.
Results: In the visual analysis, IQ was significantly higher by 10 mm Gaussian filtering, compared to other sizes of filter (PP=0.923 and 0.855 for readers 1 and 2, respectively). SNR was significantly higher in 10 mm Gaussian filter. There was a significant difference in stress and rest MBF
between several vascular territories. However CFR was not significantly different according to various filtering methods.
Conclusion: Post-reconstruction Gaussian filtering with a filter size of 10 mm significantly enhances the IQ of N-13 ammonia PET-CT, without changing the results of CFR calculation.
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Keywords


1. Lang K, Mosinger J, Wagnerová D. Photophysical properties of porphyrinoid sensitizers noncovalently bound to host molecules; models for photodynamic therapy. Coordination chemistry reviews. 2004;248:321‐50.

2. Bonnett R, Martı́nez G. Photobleaching of sensitisers used in photodynamic therapy.Tetrahedron. 2001;57: 9513‐47.

3. Andrade SM, Costa S. Spectroscopic studies on the interaction of a water soluble porphyrin and two drug carrier proteins. Biophys J. 2002;82:1607‐19.

4. Berenbaum M, Akande S, Bonnett R, Kaur H, Ioannou S, White R, et al. Meso‐Tetra(hydroxyphenyl) porphyrins, a new class of potent tumor photosensitisers with favorable selectivity. Br J Cancer. 1986;54:717.

5. Lambrechts SA, Aalders MC, Verbraak FD, Lagerberg JW, Dankert JB, Schuitmaker JJ. Effect of albumin on the photodynamic inactivation of microorganisms by a cationic porphyrin. J Photochem Photobiol B. 2005;79:51‐7.

6. Gantchev TG, Ouellet R, van Lier JE. Binding interactions and conformational changes induced by sulfonated aluminum phthalocyanines in human serum albumin. Arch Biochem Biophys. 1999;366:21‐30.

7. An W, Jiao Y, Dong C, Yang C, Inoue Y, Shuang S. Spectroscopic and molecular modeling of the binding of meso‐tetrakis (4‐hydroxyphenyl) porphyrin to human serum albumin. Dyes and Pigments. 2009;81:1‐9.

8. Allison BA, Pritchard PH, Levy JG. Evidence for low‐density lipoprotein receptor‐mediated uptake of benzoporphyrin derivative. Br J Cancer. 1994; 69: 833.

9. Rovers J, Saarnak A, Molina A, Schuitmaker J, Sterenborg H, Terpstra O. Effective treatment of liver metastases with photodynamic therapy, using the second‐generation photosensitizer meta‐tetra (hydroxyphenyl) chlorin (mTHPC), in a rat model. Br J Cancer. 1999;81:600‐8.

10. Hambright P, Fawwaz R, Valk P, McRae J, Bearden A. The distribution of various water soluble radioactive metalloporphyrins in tumor bearing mice. Bioinorg Chem. 1975;5:87‐92.

11. Whelan HT, Kras LH, Ozker K, Bajic D, Schmidt MH, Liu Y, et al. Selective incorporation of111Inlabeled PHOTOFRIN™ by glioma tissuein vivo. J Neurooncol. 1994;22:7‐13.

12. Bhalgat MK, Roberts JC, Mercer‐Smith JA, Knotts BD, Vessella RL, Lavallee DK. Preparation and biodistribution of copper‐67‐labeled porphyrins and porphyrin‐A6H immunoconjugates. Nucl Med Biol. 1997; 24:179‐85.

13. Subbarayan M, Shetty S, Srivastava T, Noronha O, Samuel A. Evaluation studies of technetium‐99mporphyrin (T3, 4BCPP) for tumor imaging. J Porphyrins Phthalocyanines. 2001;5:824‐8.

14. Kavali RR, Chul Lee B, Seok Moon B, Dae Yang S, Soo Chun K, Woon Choi C, et al. Efficient methods for the synthesis of 5‐(4‐[18F] fluorophenyl)‐10, 15, 20‐tris (3‐methoxyphenyl) porphyrin as a potential imaging agent for tumor. J Label Compd Radiopharm. 2005;48:749‐58.

15. Das T, Chakraborty S, Sarma H, Banerjee S. A novel [109Pd] palladium labeled porphyrin for possible use in targeted radiotherapy. Radiochimica Acta. 2008;96:427‐33.

16. Yamazaki K, Hirata S, Nakajima S, Kubo Y, Samejima N, Sakata I. Whole‐body Autoradiography of Tumor‐bearing Hamsters with a New Tumor Imaging Agent, Indium‐111‐labeled Porphyrin. Jpn J Cancer Res. 1988;79:880‐4.

17. Quastel M, Richter A, Levy J. Tumour scanning with indium‐111 dihaematoporphyrin ether. Br J Cancer. 1990;62:885. 

18. Sadeghpour H, Jalilian AR, Akhlaghi M, Kamalidehghan M, Mirzaii M. Preparation and Biodistribution of [111In]‐rHuEpo for Erythropoietin Receptor Imaging. J Radioanal Nucl Chem. 2008; 278:117‐122. 

19. Mirzaii M, Afarideh H, Haji‐Saied SM, Ardaneh K.Production of 111 In by irradiation of natural cadmium with deuterons and protons in NRCAM cyclotron. Energy (MeV). 1998; 6: 16. 

20. Sangster J. Octanol‐water partition coefficients of simple organic compounds. Washington DC: American Chemical Society and the American Institute of Physics for the National Institute of Standards and Technology; 1989. 

21. United States Pharmacopoeia 28, 2005, NF 23, p.1009. 

22. United States Pharmacopoeia 28, 2005, NF 23, p.1895. 

23. Bernard C. Chemistry of Metal Radionuclides (Rb,Ga, In, Y, Cu and Tc)