 This is a wonderful illustrative example of some pathology that I want to point out. So this was a patient who had a fall from a ladder and had extensive soft tissue injury to the scalp. That was demonstrated, as you can see, more posteriorly, both on the right side and the left side. Notice that the patient has some surgical staples here, which are from the correction of the lacerations that the patient had and has active hemorrhage in the scalp. However, as you scroll through here, you notice that there doesn't seem to be all that much with regard to the brain injury, despite the scalp abnormality. This is a case where you have to be pretty sharp to pick up the abnormality. I'm going to go from the thick sections to the thin sections. I'm happy to report that I detected the abnormality at the time of the original CT scan, and what one sees is just a small amount of intraventricular hemorrhage. It seems to be just on the left side. So how is it that a patient who has had significant head trauma is showing just a small amount of intraventricular hemorrhage? Well, this is a usesome pearl. If you see intraventricular hemorrhage and no other area of hemorrhage in the brain to explain it, the reason for the hemorrhage is a shearing injury of the corpus callosum. Now, I can't demonstrate for you that shearing injury of the corpus callosum, you may wonder, is it a little bit low density here in the corpus callosum at the top? I cannot demonstrate it, but I can assure you that on subsequent MRI scans, you will find a shearing injury of the corpus callosum if you have a patient with head trauma that only has intraventricular hemorrhage. Sometimes you'll see intraventricular hemorrhage in association with a parenchymal hemorrhage that perforates into the ventricular system, or sometimes you'll have blood in the ventricles in a patient who has diffuse subarachnoid hemorrhage and it gets resorbed into it. In this case, we don't see any subarachnoid hemorrhage. We don't see a subdural hematoma. We don't see a parenchymal hematoma. All we have is a small amount of intraventricular hemorrhage. When you see that, order an MRI with susceptibility-weighted imaging on this patient. Let's check the MRI. On your MRI scan, you want to look at the susceptibility-weighted images. Why is that? Subtle hemorrhage may be missed on FASPINECHO scanning because of the refocusing 180 degree pulses with FASPINECHO imaging that actually leads to decreased sensitivity to blood prox. This, although there is motion artifact, this is our patient's susceptibility-weighted scan. What one sees is the hemorrhage that was detected on the CT scan in the ventricle. Not only that, but as we go further superiorly, sure enough, as Dr. Usum predicted, there is this dark signal intensity at the top of the corpus callosum and in the spleenium of the corpus callosum. This is deoxyhemoglobin demonstrated on a susceptibility-weighted scan within the top of the corpus callosum and spleenium of the corpus callosum, identifying this patient as having had a significant shearing injury that tore the largest white matter track in the brain, the corpus callosum. You also note on the susceptibility-weighted scan that there are additional areas of dark signal intensity here at the gray-white matter junction in the right frontal lobe, in the left parietal lobe, in the left occipital lobe, and more superiorly in the frontal lobe. Again, at the typical locations for a shearing injury, the gray-white junction, which we'll talk about shortly when we talk about rotational injuries and diffusaxonal injury, but my point really was to remember intraventricular hemorrhage, isolated intraventricular hemorrhage in the face of head trauma is due to a tear in the spleenium of the corpus callosum until proven otherwise, recommend MRI.