Metal Artifact Reduction Algorithm enables reduce metal artifact and recover low contrast CT value : A Phantom Study

Congress:

ECR 2013

Poster Number:

C-1222

Type:

Scientific Exhibit

Keywords:

CT, Pelvis, Extremities, Abdomen, Comparative studies, Artifacts

Authors:

T. Fujioka¹, T. Osonoi¹, K. Fukuda¹, H. Osakabe², D. Suzuki¹, A. Koizumi¹, M. Igarashi¹, F. Nakagawa¹; ¹Minatoku, Tokyo/JP, ²Tokyo/JP

DOI:

10.1594/ecr2013/C-1222

DOI-Link:

https://dx.doi.org/10.1594/ecr2013/C-1222

Fig. 1: Structure of the phantom

Fig. 2: Placed ROI for MAI Measurement

Fig. 3: FBP Image

Fig. 4: O-MAR Image

Fig. 5: Reference Image

Fig. 6: each low contrast module of CT value and SD

Fig. 7: CT Value , SD & Metal Artifact Index in each image

Purpose

Introduction In the last 4 decades X-ray computed tomography (CT) has continually matured, and it now constitutes a powerful tool in medical diagnostics. As a non-invasive imaging technique, the use of CT has become essential, especially since the advent of Multi Detector-law CT (MDCT) in the 2000s, which led to shorter scan times and improved 3D spatial resolution. However, the quality of images generated with a CT scanner can still be deteriorated by the presence of metal objects in the field of view. Images of...

Methods and Materials

CT data acquisition and Materials This evaluation was performed by phantom (Multi Slice CT Phantom MHT Type: Low Contrast phantom, Kyoto Kagaku, Ltd.) which has 4 low contrast modules (3mm, 5mm, 7mm, 10mm diameters; Reference CT value of low contrast module and base module were 65HU and 50HU.) between 2 metal objects . (Fig1) We scanned phantom with 128 Slice CT (Ingenuity CT, PHILIPS Healthcare). Scan parameters were fixed to 120kV and 400mAs. The image was reconstructed by O-MAR and FBP. In addition, we scanned...

Results

Result 1（Visual evaluation of Low contrast detectability） All low contrast Modules was not detected in imaging with FBP. All readers' score was the same. (fig.3) In case of imaging with O-MAR, low contrast Modules were detected 5mm, 7mm, 10mm. All readers' score was the same. (fig.4) In case of imaging with Reference FBP, low contrast Modules were detected 5mm, 7mm, 10mm. All readers' score was the same. (fig.5) Result 2（Measurement CT Value and standard deviation of Low contrast Modules）(fig.6) In case of FBP image compared...

Conclusion

O-MAR enables to reduce metal artifact and recover CT value. Therefore, O-MAR can restore low contrast modules of FBP images by reducing metal artifacts. In conclusion, O-MAR has usefulness in the diagnosis of internal organs with implanting metal object subcutaneously.

References

1. Oliver Watzke., Willi A. Kalender. A pragmatic approach to metal artifact reduction in CT:　merging of metal artifact reduced images. Eur Radiol (2004) 14:849–856 2. Hua Li., Camille Noel. et al. Clinical evaluation of a commercial orthopedic metal artifact reduction tool for CT simulations in radiation therapy. Med. Phys. 39 (12), December 2012:7508-7517 3. Metal Artifact Reduction for Orthopedic Implants (O-MAR). Philips HealthCare System 2012　[available　URL　:http://clinical.netforum. healthcare.philips.com/us_en/Explore/White-Papers/CT/Metal-Artifact-Reduction-for-Orthopedic-Implants-(O-MAR)]. 4. Xiao Zhu Lin., Fei Miao,. et al. High-Definition CT Gemstone Spectral Imaging of the...

Personal Information

Taisuke Fujioka Radiographer. Department of CT Application, Philips Electronics Japan,Ltd. Minato-ku.Tokyo.Japan. E-mail:[email protected]