Hello, everyone. This video is on skull X-ray. I will review the indications then go through anatomy then the techniques used for skull radiography and finally finish with some common examples identified in skull radiograph. In the past, skull radiographs are used widely with widespread availability of CT and MRI. Skull radiography is used less frequently. In my practice, these are the scenarios in which I'm using skull radiographs. Children with suspected child abuse as a part of skeletal survey in malignancy assessment, post-surgical assessment of hardware, screening before magnetic resonance imaging in patients with cancer and for intraoperative foreign body, screening for suspected retained intraoperative foreign body, and VP shunt catheter assessment. Let's start with the anatomy. Skull is divided into cranium and facial bones. Cranium is the upper and posterior part, which encloses the brain, facial skeleton is the anterior part of the skull. Skull is formed of 22 bones; 21 bones are fixed and one bone is mobile, which is the mandible. These are some of the representative images from 3D model of a pediatric skull. Some of the landmarks which I'm going to show in this 3D model will be useful in understanding skeletal radiograph. Now let's start with the frontal view, identify the frontal bones, orbits, floor of the orbits, nasal cavity, nasal bones, maxilla, upper teeth, lower teeth, mandible. Let's identify the anatomy in the lateral view, identify the frontal bone, parietal bone, temporal bone, occipital bone, between the bones we have the sutures. In this pediatric patient we also have mastoid fontanelle, identify the orbits, nasal bones, floor of the orbit, anterior nasal spine, upper teeth, lower teeth, mento process, opening of the ear external auditory canal. Now, let's look at the skull from the top this is the anterior aspect this is the posterior aspect, frontal bones, parietal bone. Between the frontal and parietal bone, we have the coronal suture, between the parietal bones we have the sagittal suture. Now, looking at the skull from behind we have the occipital bone, we have the parietal bones, then the lambdoid suture. Now, let's identify some of the structures in frontal view of the skull. Frontal sinus, orbits, floor of the orbits, zygomatic process, mandible, odontoid process of C2 vertebral body, mastoid air cells, maxillary sinus. Also, notice microplate and screws in the body of the mandible, and ramus of the mandible in this patient. Let's identify the structures in lateral view. Frontal bone, frontal sinus, nasal bone, ethmoid sinus, maxillary sinus, mandible, occipital bone, mastoid air cells, pituitary fossa, and parietal bone. In terms of assessing the skull, these are some of the standard views which is done in my practice. There are also a lot of supplemental views which were done in the past. These are of limited utility in the current setting due to widespread usage of CT scanners. PA view is a nonangled radiograph, which gives whole of your entire skull. The patient deselect patient's forehead touches the X-ray detector. The line connecting the orbit to the external auditory canal is perpendicular to the detector. The X-ray beam goes through the skull without any angulation. PA view decreases the radiation to the eyes compared to AP view, lesser magnification of the facial bones when compared to the AP view. However, overlap of facial bone structures limits evaluation of the sinuses. AP view is a nonangled radiograph. Again notice there is zero angulation between the line connecting the orbit to the external auditory canal. It gives all view of the entire skull. This view may be necessary in patients who cannot be easily or quickly rotated to obtain PA radiograph. The disadvantages are similar to AP radiograph due to overlap of facial bones, or the sinuses. Also, there is magnification of the facial bones and there is increased radiation to the eyes. Lateral view is a nonangled radiograph, the X-ray beam travels through the skull and hits the detector perpendicularly. This view gives overview of entire skull. Caldwell view is an angled PA radiograph, is better for evaluation of the paranasal sinuses particularly frontal sinus. Waters view is again an angled PA radiograph. In this view the line connecting the mento process to the external auditory canal is perpendicular this view allows better assessment of the sinuses. Now, let's identify some common pathologies. This is a really old patient who was brought to the emergency department with suspected scalp mass. Notice the normal coronal suture and lambdoid suture. There's an additional lucent line which is fracture in the parietal bone. This patient went on to have additional views of the entire skeleton, which shows rib fractures and fractures in the lower extremity consistent with non-accidental injury. This is a three-week-old patient brought to the emergency department with scalps swelling. This kid had a traumatic delivery with use of instruments. Notice calcified hematoma in the left parietal region consistent with cephalohematoma. This is a patient with suspected underlying malignancy. Skull radiograph was obtained as part of skeletal series. Notice [inaudible] fossa in the cranium and mandible consistent with metastatic lesions which turned out to be multiple myeloma. This X-ray is part of skeletal series in this patient with suspected malignancy. Notice multiple cotton wool-like hyperdense lesions in the skull. These lesions are subsequently found to be related to underlying Paget's disease. This is a patient transferred from outside institution that's concern for stroke. CT brain was negative, so clinical team requested MRI examination. Patient had history of facial trauma. That surgery however we did not have access to any of the prior imaging. This X-ray was obtained as a part of screening for MRI, to exclude any intraocular foreign body. Notice hyperdense foreign body projecting in the region of right orbits. This patient could not have MRI examination. This is a patient who had a vestibular schwannoma underwent surgery through suboccipital craniectomy. There was concern for retained micropatties in the lateral view on the zoomed image identifying the foreign body, which was confirmed on the subsequent post-operative CT scan, in the post-surgical fossa. These are two different patients with suspected orbital floor fracture. Identify the normal orbital floor, which is straight. In this patient on the left side notice teardrop shaped fracture of the left orbital floor and in this patient notice discontinuity in the right orbital floor. This is a patient with suspected nasal trauma, notice nasal bone fractures. This is a patient with trauma to the face, notice fractures going through the right side of the body of the mandible through the left side of the ramus of the mandible, also seen in the lateral views. This is a patient with a history of facial trauma who underwent surgery, radiographs are obtained to assess the position of the microplate and screws. Notice multiple microplate and screws in bilateral maxilla, and mandible both in AP and lateral views. This is a patient who complained of facial pain. Radiograph shows bilateral maxillary sinus disease, notice had fluid level in bilateral maxillary sinus. This is a patient with chiari malformation where VP shunt placement came to emergency department with headache and vomiting. Radiographs are obtained to make sure the VP shunt catheter was not disconnected. Frontal view shows left parietal approach VP shunt catheter, lateral view shows there is no discontinuity in the tubing. In summary skull radiographs are performed less frequently due to widespread availability of CT. Skull radiograph still have specific role in assessment of skull pathologies. We reviewed some common indications, discussed anatomy relevant to evaluation of skull radiographs. Finally, reviewed some common pathologies which were identified with skull radiographing. Thanks for your attention.
