Experimental application of an automated alignment correction algorithm for geological CT imaging: phantom study and application to sediment cores from cold-water coral mounds
Tóm tắt
In computed tomography (CT) quality assurance, alignment of image quality phantoms is crucial for quantitative and reproducible evaluation and may be improved by alignment correction. Our goal was to develop an alignment correction algorithm to facilitate geological sampling of sediment cores taken from a cold-water coral mount. An alignment correction algorithm was developed and tested with a CT acquisition at 120 kVp and 150 mAs of an image quality phantom. Random translation (maximum 15 mm) and rotation (maximum 2.86°) were applied and ground-truth was compared to parameters determined by alignment correction. Furthermore, mean densities were evaluated in four regions of interest (ROIs) placed in the phantom low-contrast section, comparing values before and after correction to ground truth. This process was repeated 1000 times. After validation, alignment correction was applied to CT acquisitions (140 kVp, 570 mAs) of sediment core sections up to 1 m in length, and sagittal reconstructions were calculated for sampling planning. In the phantom, average absolute differences between applied and detected parameters after alignment correction were 0.01 ± 0.06 mm (mean ± standard deviation) along the x-axis, 0.11 ± 0.08 mm along the y-axis, 0.15 ± 0.07° around the x-axis, and 0.02 ± 0.02° around the y-axis, respectively. For ROI analysis, differences in densities were 63.12 ± 30.57, 31.38 ± 32.10, 18.27 ± 35.57, and 9.59 ± 26.37 HU before alignment correction and 1.22 ± 1.40, 0.76 ± 0.9, 0.45 ± 0.86, and 0.36 ± 0.48 HU after alignment correction, respectively. For sediment core segments, average absolute detected parameters were 3.93 ± 2.89 mm, 7.21 ± 2.37 mm, 0.37 ± 0.33°, and 0.21 ± 0.22°, respectively. The alignment correction algorithm was successfully evaluated in the phantom and allowed a correct alignment of sediment core segments, thus aiding in sampling planning. Application to other tasks, like image quality analysis, seems possible.
Tài liệu tham khảo
McCollough CH, Bruesewitz MR, McNitt-Gray MF et al (2004) The phantom portion of the American College of Radiology (ACR) computed tomography (CT) accreditation program: practical tips, artifact examples, and pitfalls to avoid. Med Phys 31:2423–2442
Titschack J, Baum D, De Pol-Holz R et al (2015) Aggradation and carbonate accumulation of Holocene Norwegian cold-water coral reefs. Sedimentology 62:1873–1898
Titschack J, Fink HG, Baum D, Wienberg C, Hebbeln D, Freiwald A (2016) Mediterranean cold-water corals–an important regional carbonate factory? The Depositional Record 2:74–96
Bahr A, Albuquerque A, Ardenghi N et al (2016) South American hydrological balance and paleoceanography during the Late Pleistocene and Holocene (SAMBA)–cruise no. M125, march 21–April 15, 2016-Rio de Janeiro (Brazil)–Fortaleza (Brazil). METEOR-Berichte. https://doi.org/10.2312/cr_m125
Raddatz J, Liebetrau V, Trotter J et al (2016) Environmental constraints on Holocene cold-water coral reef growth off Norway: insights from a multiproxy approach. Paleoceanography 31:1350–1367
Raddatz J, Rüggeberg A, Liebetrau V et al (2014) Environmental boundary conditions of cold-water coral mound growth over the last 3 million years in the Porcupine Seabight, Northeast Atlantic. Deep Sea Res Part 2 Top Stud Oceanogr 99:227–236
Pahn G, Skornitzke S, Schlemmer HP, Kauczor HU, Stiller W (2016) Toward standardized quantitative image quality (IQ) assessment in computed tomography (CT): a comprehensive framework for automated and comparative IQ analysis based on ICRU report 87. Phys Med 32:104–115
Johnson HJ, McCormick MM, Ibáñez L (2015) The ITK software guide book 2: design and functionality. Kitware, Inc. https://itk.org/ITKSoftwareGuide/html/Book2/ITKSoftwareGuide-Book2.html
Steiding C, Kolditz D, Kalender WA (2014) A quality assurance framework for the fully automated and objective evaluation of image quality in cone-beam computed tomography. Med Phys 41:031901
Torfeh T, Beaumont S, Guédon J, Normand N, Denis E (2007) Software tools dedicated for an automatic analysis of the CT scanner quality control images. Proceedings of the SPIE - medical imaging <https://doi.org/10.1117/12.707343>. <hal-00326646>. https://hal.archives-ouvertes.fr/hal-00326646/document