Automatic ultrasound–MRI registration for neurosurgery using the 2D and 3D LC2 Metric

To enable image guided neurosurgery, the alignment of pre-interventional magnetic resonance imaging (MRI) and intra-operative ultrasound (US) is commonly required. We present two automatic image registration algorithms using the similarity measure Linear Correlation of Linear Combination (LC2) to align either freehand US slices or US volumes with MRI images. Both approaches allow an automatic and robust registration, while the three dimensional method yields a significantly improved percentage of optimally aligned registrations for randomly chosen clinically relevant initializations. This study presents a detailed description of the methodology and an extensive evaluation showing an accuracy of 2.51 mm, precision of 0.85 mm and capture range of 15 mm (>95% convergence) using 14 clinical neurosurgical cases.

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• Automatic registration using similarity measure Linear Correlation of Linear Combination (LC2).
• 2D and 3D implementation for US slices or US volumes with MRI images.
• Extensive evaluation showing an accuracy of 2.51 mm, precision of 0.85 mm and capture range of 15 mm.
• LC2 exhibits a distinctive extremum when images are optimally aligned.
• LC2 shape provides optimal support in finding this extremum.