CT Scan Protocols (PDF)

COMPUTED TOMOGRAPHY  SINUSES CT SCAN  Prepared By: Ahmed Jasem Abass MSC Medical Imaging  BY AHMED JASEM ABASS  MSC of Medical  Imaging Screening Sinus CT  CT of the sinuses primarily is used to: 1.Detect the presence of inflammatory diseases. 2.Plan for surgery by defining anatomy...

COMPUTED TOMOGRAPHY  SINUSES CT SCAN  Prepared By: Ahmed Jasem Abass MSC Medical Imaging  BY AHMED JASEM ABASS  MSC of Medical  Imaging Screening Sinus CT  CT of the sinuses primarily is used to: 1.Detect the presence of inflammatory diseases. 2.Plan for surgery by defining anatomy or giving further information about tumors of the nasal cavity and sinuses. 3.Evaluate sinuses that are filled with fluid or thickened sinus membranes. 4.Help diagnose sinusitis.  Scout image: Patient is placed supine. The alignment of the scan is perpendicular to the hard palate. Contrast: 100cc Omnipaque 300 IV, R/O sinus or nasal cavity tumor  kVp / Effective mAs / Rotation time (sec) 120 / 130 / 0.75  FOV : 180 mm.  Thickness: 3 mm.  Bone Window: WC : 200, WW : 2000  Soft Tissue Window: WC : 50, WW : 350 Scan Coverage: Maxillary teeth through frontal sinusesThe scan is set up to start posterior to the sphenoid sinus and continued anteriorly through the frontal sinuses and anterior face. Maxillary Sinus Ethmoid Sinus Sphenoid Sinus Coronal reconstructions Sagittal reconstructions (back of sphenoid sinus through (through all sinuses) nose) CT axial view shows a A computed well-defined expansile tomography lesion (black arrow) sagittal view of a with sclerotic margin frontal sinus active ( red arrow), scattered ossifying fibroma. calcification within the CT coronal view shows lesion (yellow arrow). an expansile lesion in the right maxilla exhibiting features of calcification, presence of teeth displaced due to the lesion (black arrow) and involving the floor of the maxillary sinus. Axial image with arrow Axial image demonstrating Coronal image with pointing to air-fluid level additional case of acute arrow pointing to in maxillary sinus in acute sinusitis with arrows pointing right maxillary sinusitis. to air-fluid levels in the sinus Mucus Ethmoid and sphenoid Retention Cyst sinuses (MRC). Coronal image with arrow pointing to maxillary sinus polyp. Often on imaging a polyp and mucus retention cyst cannot be differentiated TEMPORAL BONE CT SCAN Temporal Bone CT  Temporal bone CT, also known as mastoid bone CT is typically ordered to evaluate the outer ear, bones of the ear and inner ear structures for infection, tumor, injury or congenital or acquired hearing disorders.  Scout Image: The patient is placed supine. The alignment of the plane is parallel to the Orbitomeatal line. kVp / Effective mAs / Rotation time (sec): 120 / 160 / 1.0  Contrast: 100cc Omnipaque 300 IV, R/O Some Malignant Lesions.  Reconstruction Filter: Ultra High Bone Algorithm.  Thickness : 1 mm.  Resolution : High.  Bone Window: WC: 400, WW: 4000  Soft Tissue Window: WC: 50, WW: 350  Submit images in bone and soft tissue algorithm.  Scan Coverage: Above Petrous ridges to tip of mastoids, This is set up to start at the top of the anterior arch of C1, and scan superiorly to the roof of the mastoid air cells. Mandibular Condyle External Auditory Canals Mastoid Air Cells Temporal Bone Fracture FACIAL BONE CT SCAN Facial Bones CT (also use for mandible protocol)  A CT of the Facial Bones is an exam that takes thin slice (2 - 3.5 mm) images of the facial bone structure, including the jaw, nose, eye sockets and cheek bones. These images are helpful in the diagnosis of facial trauma and malformations.  Scout Image: Patient is placed supine. Bone Window: WC : 200, WW : 2000  Soft Tissue Window: WC : 50, WW : 350  Submit images in bone and soft tissue algorithm. Scan Coverage: below the Mandible through Frontal Sinuses. The scan is set up to start below the mandible and continue superiorly through the frontal sinuses. Coronal reconstructions Sagittal reconstructions external auditory canals through Zygomatic arches through nasal bones (a) Simple nasal fracture. (b) Complex nasal fracture, note the fracture of the nasal septum. three-dimensional (3-D) model made 3-dimensional reconstruction from a CT scan showing a broken of the fracture under the eye- (fractured) cheekbone that extends socket on the right side of the into the gum of the mouth. image. Orbit CT  A CT of the Orbits is an exam that takes thin slice images of the eyes and orbital socket at three different angles. This allows for the diagnosis of a range of conditions such as injury, disease and congenital defects.  Scout Image: Patient is placed supine. Contrast: 100cc Omnipaque 300 IV, R/O infection/abscess; assess orbital tumor; R/O lacrimal gland pathology; optic atrophy.  kVp / Effective mAs / Rotation Time (sec) 120 / 170 / 0.75  Resolution: High.  Bone Window: WC : 200, WW : 2000  Soft Tissue Window: WC : 50, WW : 350  Submit images in bone and soft tissue algorithm. Scan Coverage: Mid maxillary sinus to frontal sinuses. The scan is set up to start at the hard palate and continue superiorly through the orbits above Frontal Sinuses.. Coronal reconstructions Sagittal reconstructions Orbit CT – Soft Tissue Window (Axial Plane) Orbit CT – Bone Window (Axial Plane)  Orbit CT – Bone Window (Coronal Plane) Orbit CT – Soft Tissue Window (Coronal Plane) Orbit CT – Soft Tissue Window (Sagittal Plane) Orbit CT – Bone Window (Sagittal Plane)  ORBIT CT (with contrast) Right orbital blow-out fracture on CT-scan; coronal reformat Thank You BEST WISHES FOR ALL