A controller for registering a magnetic resonance imaging image to a tracking space that includes a tracked ultrasound probe and an organ captured in an ultrasound image generated by the ultrasound probe, comprising: a memory (492, 620, 630) that stores instructions; and a processor (491, 610) that executes the instructions, wherein, when executed by the processor, the instructions cause the controller to execute a process comprising: obtaining (S110, S120, S130, S331) 2-dimensional coordinates of a midsagittal cut through a segmentation of the organ based on an intersection of a 3-dimensional segmented magnetic resonance imaging volume that includes the segmentation of the organ and a midsagittal plane through the organ; controlling (S140, S341) generation of a 3-dimensional ultrasound volume; segmenting (S140, S351) the 3-dimensional ultrasound volume to obtain a segmented 3-dimensional ultrasound volume; identifying (S150, S361) the midsagittal plane of the organ in the segmented 3-dimensional ultrasound volume to identify an ultrasound midsagittal plane; generating (S150, S371), using a tracked ultrasound probe, a tracking position in the tracking space of an ultrasound image of the midsagittal plane of the organ; registering (S170, S381) a 2-dimensional segmented ultrasound representation of the midsagittal plane of the organ provided by the ultrasound midsagittal plane to a 2-dimensional segmented magnetic resonance imaging representation of the midsagittal plane of the organ to obtain an image registration of the midsagittal plane of the organ; and generating (S180, S391) a registration of the 3-dimensional magnetic resonance imaging volume to the tracking space based on the 2-dimensional coordinates of the midsagittal plane of the segmentation of the organ, the image registration of the midsagittal plane of the organ, and the tracking position in the tracking space of the ultrasound image of the midsagittal plane. a memory (492, 620, 630) that stores instructions; and a processor (491, 610) that executes the instructions, wherein, when executed by the processor, the instructions cause the controller to execute a process comprising: obtaining (S110, S120, S130, S331) 2-dimensional coordinates of a midsagittal cut through a segmentation of the organ based on an intersection of a 3-dimensional segmented magnetic resonance imaging volume that includes the segmentation of the organ and a midsagittal plane through the organ; controlling (S140, S341) generation of a 3-dimensional ultrasound volume; segmenting (S140, S351) the 3-dimensional ultrasound volume to obtain a segmented 3-dimensional ultrasound volume; identifying (S150, S361) the midsagittal plane of the organ in the segmented 3-dimensional ultrasound volume to identify an ultrasound midsagittal plane; generating (S150, S371), using a tracked ultrasound probe, a tracking position in the tracking space of an ultrasound image of the midsagittal plane of the organ; registering (S170, S381) a 2-dimensional segmented ultrasound representation of the midsagittal plane of the organ provided by the ultrasound midsagittal plane to a 2-dimensional segmented magnetic resonance imaging representation of the midsagittal plane of the organ to obtain an image registration of the midsagittal plane of the organ; and generating (S180, S391) a registration of the 3-dimensional magnetic resonance imaging volume to the tracking space based on the 2-dimensional coordinates of the midsagittal plane of the segmentation of the organ, the image registration of the midsagittal plane of the organ, and the tracking position in the tracking space of the ultrasound image of the midsagittal plane. obtaining (S110, S120, S130, S331) 2-dimensional coordinates of a midsagittal cut through a segmentation of the organ based on an intersection of a 3-dimensional segmented magnetic resonance imaging volume that includes the segmentation of the organ and a midsagittal plane through the organ; controlling (S140, S341) generation of a 3-dimensional ultrasound volume; segmenting (S140, S351) the 3-dimensional ultrasound volume to obtain a segmented 3-dimensional ultrasound volume; identifying (S150, S361) the midsagittal plane of the organ in the segmented 3-dimensional ultrasound volume to identify an ultrasound midsagittal plane; generating (S150, S371), using a tracked ultrasound probe, a tracking position in the tracking space of an ultrasound image of the midsagittal plane of the organ; registering (S170, S381) a 2-dimensional segmented ultrasound representation of the midsagittal plane of the organ provided by the ultrasound midsagittal plane to a 2-dimensional segmented magnetic resonance imaging representation of the midsagittal plane of the organ to obtain an image registration of the midsagittal plane of the organ; and generating (S180, S391) a registration of the 3-dimensional magnetic resonance imaging volume to the tracking space based on the 2-dimensional coordinates of the midsagittal plane of the segmentation of the organ, the image registration of the midsagittal plane of the organ, and the tracking position in the tracking space of the ultrasound image of the midsagittal plane.