Figure 4A shows a coronal anatomical slice through the canine brain. The falx (F), cingulate sulcus (CS) and one of the lateral ventricles (LV) are labeled. Figure 4B shows a 3 cm deep B-mode image of the coronal plane also showing the Falx (F), cingulated sulcus (CS) and lateral ventricle (LV) prior to the LV being punctured by a needle. The needle (N) is viewed in Figure 4C after insertion. Figure 4D is an MRI of a para-sagittal plane through a lateral ventricle of a different canine brain. The lateral ventricle (LV) is white in the MRI image. Figure 4E shows the simultaneous orthogonal B-scan to Figure 4B. Again, we see the LV before the needle is inserted. Figure 4F shows the same B-scan plane with the needle (N) inserted into the LV. This plane was obtained simultaneously with Figure 4C and is orthogonal to Figure 4C. Figure 4G is the simultaneous real-time rendered view of the LV before the needle is inserted. We also see the Falx (F) in this image. Figure 4H, displayed simultaneously with Figure 4C and 4F, shows the needle (N) after being inserted into the LV.