SU-FF-I-135: Breast Density Measurement with Cone-Beam CT and MRI: A Post Mortem Study

Purpose. To develop a dual energy imaging method to improve the accuracy of electron density measurement with a cone-beam CT (CBCT) device.Materials and Methods. The imaging system is the XVI CBCT system on Elekta Synergy linac. Projection data were acquired with the high and low energy X-ray, respectively, to set up a basis material decomposition model. Virtual phantom simulation and phantoms experiments were carried out for quantitative evaluation of the method. Phantoms were also scanned twice with the high and low energy X-ray, respectively. The data were decomposed into projections of the two basis material coefficients according to the model set up earlier. The two sets of decomposed projections were used to reconstruct CBCT images of the basis material coefficients. Then, the images of electron densities were calculated with these CBCT images.Results. The difference between the calculated and theoretical values was within 2% and the correlation coefficient of them was about 1.0. The dual energy imaging method obtained more accurate electron density values and reduced the beam hardening artifacts obviously.Conclusion. A novel dual energy CBCT imaging method to calculate the electron densities was developed. It can acquire more accurate values and provide a platform potentially for dose calculation.

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Imaging artifacts of Onyx and PHIL on conventional CT, cone-beam CT and MRI in an animal model

Interventional Neuroradiology ◽

10.1177/1591019918782692 ◽

2018 ◽

Vol 24 (6) ◽

pp. 693-701 ◽

Cited By ~ 11

Author(s):

Dominik F Vollherbst ◽

Ruth Otto ◽

Thuy Do ◽

Hans U Kauczor ◽

Martin Bendszus ◽

...

Keyword(s):

Cone Beam Ct ◽

Cone Beam ◽

Embolic Agent ◽

In Vivo Model ◽

Ethylene Vinyl Alcohol ◽

Embolic Agents ◽

Liquid Embolic ◽

Conventional Ct ◽

Ct And Mri

Background and purpose A frequently reported drawback of ethylene vinyl alcohol copolymer-based liquid embolic agents is the production of artifacts in diagnostic imaging. New embolic agents, such as Precipitating hydrophobic injectable liquid (PHIL; MicroVention, Tustin, CA, USA), are supposed to induce significantly fewer artifacts. The purpose of this study is to assess the degree of artifacts induced by the liquid embolic agents Onyx (Medtronic Neurovascular, Irvine, CA, USA) and PHIL in conventional computed tomography (CT), cone-beam CT and magnetic resonance imaging (MRI) in an experimental in vivo model. Materials and methods In 10 pigs the rete mirabile was embolized with Onyx ( n = 5) or PHIL ( n = 5). After embolization, conventional CT, cone-beam CT and MRI were performed. The degree of artifacts was graded qualitatively (five-point scale; for CT and MRI) and quantitatively (HUs of well-defined regions of interest (ROIs); for CT only). Results Artifacts were significantly more severe for Onyx both in the qualitative (e.g. conventional CT: 2 versus 5 (medians); p = 0.008) and in the quantitative image analysis (e.g. cone-beam CT: standard deviation of a ROI near to the embolic agent cast, 94 HU versus 38 HU (medians); p = 0.008). Neither Onyx nor PHIL produced any apparent artifacts in MRI. Conclusion PHIL produces fewer artifacts than Onyx in conventional CT and cone-beam CT in an experimental in vivo model.

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