 Just as we employ thin-section imaging in CT scanning, we have to employ thin-section imaging on MRI as well. And usually, these are sequences that are T2-weighted, that is, that have bright CSF signal. The reason why we want bright CSF signal is so that way we can see the endolymph and the perilymph within the cochlea and vestibular system. The pulse sequences that are typically used are referred to as fiesta in the GE scanner, 3D cysts in Siemens, and TFV or turbo-fueled echo with Philips. So you will hear these terms, fast imaging employing steady-state acquisition, fiesta, constructive interference, steady-state, cyst imaging with Siemens, some people call it KISS, depending upon how romantic they are that day. But I refer to it as cyst imaging. And then we have the turbo-fueled echo or TFV with Philips. This is an example of a fiesta GE pulse sequence. As you see, the CSF is bright. And if we look at the cochlea and vestibular, we are also seeing bright signal dominating. Now, what's nice about this is that we can therefore see the cranio nerves very nicely outlined by the cerebral spinal fluid. So we can see that this cranio nerve that I'm going to mark as number one is anteriorly located. And depending upon whether we're at the upper portion of the internal artery canal or the lower portion of the internal artery canal, we would say, all right, well, if it's anterior and inferior, it's going to be the cochlea nerve. Whereas if it's anterior but superior, it's going to be one of the superior vestibular nerves. What's posterior here, and I'll mark it as two, in the internal artery canal, posterior and inferior is going to be a portion of the inferior vestibular nerve. So inferior and posterior inferior vestibular nerve, superior and posterior is going to be the superior vestibular nerve, anterior inferior, cochlear nerve, anterior superior, seventh cranio nerve. You also see on the right-hand side a pretty nice example of the medialis. Remember the skeleton of the cochlea is referred to as the medialis. And we can see the separation into the, this is actually the middle turn and the apical turn of the cochlea with its internal anatomy being the skeleton being the medialis. We're also seeing portion of the vestibular system and in this section we are also seeing a portion of the posterior semi-circular canal cut in cross-section. As with CT, these fiesta cis-turbo-fieldeco scans can be reconstructed in multi-planar view. So this is an example of use of 3D fiesta to look for superior semi-circular canal dehiscence. In this case, we've taken our axial anatomy in the fiesta sequence and we've reconstructed it in an oblique fashion to look at the semi-circular canals. And what you have here is a reconstruction through the beautifully demonstrated superior semi-circular canal coming to the vestibule. And we note that there is bone above the superior semi-circular canal between it and the brain and therefore there is no superior semi-circular canal dehiscence in this example. And these sections can be taken not only in multi-planar view but we can even reconstruct in a 3D format and make NIP images or 3D volumetric images. And here you're nicely seeing that superior semi-circular canal, the lateral semi-circular canal, the posterior semi-circular canal, the turns of the cochlea even. And this is, again, turns of the cochlea in a three-dimensional reconstruction. I want to just point out one other portion of the anatomy that is important and that is the spiral lamina. The spiral lamina divides the cochlea into the scala vestibule and the scala timpani. And this is another portion of the anatomy that is important with respect to congenital abnormalities of the cochlea and vestibule but also may be part of the problem associated with Meniere's disease. Frankly, with Meniere's disease, we really don't have great anatomic correlation with the patient's symptomatology but people are looking at this fine anatomy within the turns of the cochlea known as the spiral lamina. Here is an example of the use of cis or fiesta or turbo field echo scanning to look for cochlear nerve absence or aplasia in a patient who had congenital sensing or oral hearing loss. So this is the example, if you will, of the anatomy here the separation superior to inferior being the crystal falceiformis that I mentioned and then the separation of the anatomy anterior to posterior being Bill's bar. So again, anterior superior, seventh cranial nerve people refer to that as seven up. Cochlear nerve anterior and inferior so cochlear down, posteriorly separate into superior vestibular and inferior vestibular nerves. So let's look at that anatomy doing cross sections oblique to the internal artery canal. In this example, we can see this is the anterior the front of the face is here posteriorly with the cerebellum is here and we can see anterior and superior the seventh cranial nerve anterior and inferior the cochlear nerve and these are the superior and inferior vestibular nerves more posteriorly within the internal auditory canal. Let's shift to this patient. This patient we don't see the same anatomy we're not exactly through the same slice and in point of fact we have these anterior superior seventh cranial nerve seven up but we are missing the cochlear nerve. We have the superior vestibular nerve and the inferior vestibular nerve but we are missing this nerve which is the cochlear nerve. This is a patient who has congenital sensory neural hearing loss due to cochlear nerve apresia. Nicely demonstrated on this Cis fiesta turbo field echo three dimensional pulse sequence with the three dimensional reconstruction in an oblique coronal plane.