Towards estimating fiducial localization error of point-based registration in image-guided neurosurgery

Abstract

Abstract. Fiducial Localization Error (FLE) is one of the major reasons of inaccuracy in point-based spatial registration of Image-Guided Neurosurgery System (IGNS), and minimizing FLE is the fundamental way to improve spatial registration accuracy. A reliable estimation of FLE is needed, as it cannot be measured directly in real application of IGNS. In this paper, we propose a method to estimate the FLE in a point-based registration of IGNS. Test fiducial point sets were generated in one coordinate system around the given fiducial point set by utilizing simple random sampling. Further, these points were registered to the fiducial point set in the other coordinate system. The average position of the test fiducial point sets with small FRE are calculated and its displacement from the given fiducial point set is the parameter used to estimate the FLE of each fiducial point. The correlation between the displacement and the FLE of each fiducial point is greater than 0.75 when nine or more fiducial points were utilized. This correlation gradually increases up to 0.9 with the increase of the number of fiducial points.

Comparison of different fiducial markers to guide SPECT and CT image registration

“…Because of this heterogeneity, the second configuration, the 131 I + cotton sphere (CO) in the needle cap, was analysed for image uniformity and fiducial point errors. Although these assembly images were more homogenous than the first and they presented dpr values less than a SPECT voxel size, they could not be seen adequately on CT, producing heterogeneous regions for this modality and impacting fiducial coordinate determination in the software by operator [17].…”

“…The image registration error calculation was performed based on the Fiducial Registration Error (FRE), which is the distance between the fiducials' spatial coordinates after registration [17,18]. The parameters of spatial transformation and the coordinates of fiducials before registration were used to calculate the markers' coordinates after the process using MATLAB.…”

“…While it showed dpr values lower than a voxel size, which is about 6.5 to 6.6 mm for this hybrid device scan, there occurred a non-favourable deviation in SPECT-CT coregistration, as the content flow caused a heterogeneous fiducial SPECT image that might influence the marker location to start the registration process. Our data are according to Zhi (2015), so it was not possible to register two coordinate systems precisely due to imprecisions in fiducial spatial determination [17]. These heterogeneous markers could introduce problems in the centroid calculation or in visually choosing the intensity centre of the fiducial by operator.…”

Integration of Real-Time Image Fusion in the Robotic-Assisted Treatment of Hepatocellular Carcinoma

“…TRE is usually the most clinically relevant error. Since FLE is the basic cause of TRE, estimation of FLE in a single instance of registration is very important in the optimization of point-based registration [15,16].…”

Avaliação da viabilidade do corregistro de imagens SPECT e CT utilizando marcas fiduciais em pacientes com carcinoma diferenciado de tireoide

“…Existem algumas maneiras de avaliar as incertezas associadas ao processo de corregistro de imagens, dentre as quais o erro quadrático médio (Mean Square Error-MSE) pode ser utilizado (24). Entretanto, para o desenvolvimento deste estudo, foram calculadas as incertezas por ponto para cada marca fiducial baseadas no Erro Fiducial do Corregistro (53,54), o qual é definido como a distância entre as coordenadas das marcas fiduciais após o processo de corregistro. Este cálculo levou em consideração o corregistro rígido das imagens, no qual são empregadas apenas transformações globais do tipo rotação e translação.…”