Hi, this is Sagar Wagle one of the musculoskeletal radiology fellows at Stanford University We have a case of a 17 year old male athlete with low back pain for four months These are oblique radiographs of the spine on the left We do see this lucency that corresponds to L5 parsed defect on the right We do see this lucency as well But there is overlying ball gas and this is unclear if this is just overlying ball gas or actually a fracture Spine radiographs are insensitive for fractures The appearance of posterior elements of spine on Oblique spine radiograph is also called scotty dog appearance Let's learn about that anatomy in this 3d image generated from CT The nose of the dog is the transverse process The ear of the dog is the superior articular process The neck of the dog is the parse so the parse fracture appears as fracture of the neck The leg of the dog is the inferior articular process The body of the dog is the lamina and the spinous process. Let's look at the level of the fracture nose of the dog the transverse process Superior articular process the ear of the dog and we don't see the neck. There's a big defect in the neck So this is our parse fracture. Let's look at the radiograph. This is the nose Superior articular process and this is the neck and we see the fracture of the neck. So this is a parse fracture The eye of the dog is the pedicle This is lateral view of the spine and this is the pedicle and you can imagine that if you were to look at the Pedicle posteriorly you just see this as a circle So the pedicle would be somewhere over here So this is the pedicle Patient also had a SPECT scan We see radiotracer uptake bilaterally more on the left and the left Uptake corresponds to the fracture, but we did not see a fracture on the right, but the patient still has injury on the right side So SPECT is more sensitive than CT for fractures However, we lack the anatomic detail that we see on CT. So while SPECT is more sensitive We lack the anatomic detail. So it's pretty uncommon for people to do SPECT CT for suspected cases for fractures CT and MRI are a lot more common I have another case of a 22 year old male with six months of low back pain and We have an MRI as you scroll through the images This is L4 vodule body and we see the normal parse This is the L5 vodule body and we see that there is a parse fracture Fracture of the parse is also called Spondylolisis and if there is movement of the vodule body anterior listhesis, we call that Spondylolisthesis. In young patients Spondylolisthesis occurs mainly after fractures. In old people Spondylolisthesis can occur from arthritis of the fascia joint without having a fracture. As you scroll through the image We do see that there is mild Anterior listhesis of L5 on S1. So this case has Spondylolisthesis and Spondylolisthesis. As we go on the other side So this is L4. We do see a normal parse. On L5 the parse look normal But it is not so clear. In acute cases MRI is really sensitive for fractures because we can see the bone marrow edema But in old fractures the sensitivity of the MRI goes down and one reason is because the slice thickness The slice thickness of MRI is usually 3 millimeter But on CT the slice thickness can be made low 0.75 millimeter 1 millimeter 2 millimeter So old fractures are sometimes easy to see on CT and difficult to see on MRI But new fractures while we can see them both on CT or MRI It can be easy to see on MRI because of all the edema Patient had persistent pain and we got repeat imaging after three months. On the radiograph We can see the parse fracture. We can also see the anterior listhesis. On the CT on the right and left We can see the parse fracture Thank you for watching the video

3rd Edition, CASE 54

3rd Edition

Spine

musculoskeletal radiology

spinal fractures

imaging techniques

spondylolysis

spondylolisthesis