CT Procedures for Sinuses and Temporal Bones

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Questions and Answers

What is the primary purpose of performing a CT of the Orbits?

To evaluate spinal alignment

To detect tumors in the lungs

To diagnose conditions related to the eyes and orbital socket (correct)

To assess blood flow in the brain

What is the role of the contrast agent used in an Orbit CT scan?

To provide a clearer image of bone structures only

To enhance the visibility of soft tissues (correct)

To increase the exposure time during the scan

To measure the patient's heart rate

In an Orbit CT scan, what is the imaging window used for assessing bone structures?

Soft Tissue Window

Lateral Window

Bone Window (correct)

Coronal Window

What scan coverage is typically used for an Orbit CT?

From the maxillary sinus to the frontal sinuses Signup and view all the answers

Which of the following parameters is NOT typically adjusted for an Orbit CT scan?

Patient's weight Signup and view all the answers

What is one of the primary uses of a sinus CT scan?

Detecting the presence of inflammatory diseases Signup and view all the answers

What is the recommended thickness of the CT scan for sinuses?

3 mm Signup and view all the answers

During a sinus CT scan, where should the alignment of the scan be positioned?

Perpendicular to the hard palate Signup and view all the answers

What role does the contrast agent Omnipaque 300 IV play in a sinus CT scan?

Allows visualization of soft tissue tumors Signup and view all the answers

Which area does the scan coverage for a sinus CT scan start from?

Maxillary teeth Signup and view all the answers

What does the Bone Window setting (WC: 200, WW: 2000) in a sinus CT scan primarily highlight?

Fractures and dense structures Signup and view all the answers

In the context of sinus CT scans, what is the significance of evaluating fluid levels?

Assists in identifying acute sinusitis Signup and view all the answers

Which anatomical structures are primarily evaluated in a sinus CT scan?

Nasal cavity and sinuses Signup and view all the answers

What is the typical purpose of a temporal bone CT scan?

To assess infection, tumor, or hearing disorders in the ear Signup and view all the answers

What is the recommended thickness of slices for a facial bones CT scan?

2 - 3.5 mm Signup and view all the answers

Which window settings are used for soft tissue in a temporal bone CT scan?

WC: 50, WW: 350 Signup and view all the answers

What coverage is recommended for a temporal bone CT scan?

Above the petrous ridges to the tip of mastoids Signup and view all the answers

Which contrast agent is used for temporal bone CT scans?

Omnipaque 100cc 300 IV Signup and view all the answers

What is the primary utility of a CT scan of the facial bones?

To assist in the diagnosis of facial trauma and malformations Signup and view all the answers

In temporal bone CT scans, how is the patient positioned for the scout image?

Supine position Signup and view all the answers

Which of the following fractures is not typically assessed with a facial bones CT scan?

Temporal bone fracture Signup and view all the answers

Study Notes

Computed Tomography (CT) Procedures

CT scans are used to image sinuses, temporal bones, facial bones, orbits, and other structures.
CT scans of sinuses, facial bones, and orbits can assess for inflammatory diseases, tumors, sinusitis, facial trauma, and malformations.
CT scans of the temporal bones help diagnose infections, tumors, and hearing disorders.
CT scans of the orbit allow for diagnosis of injuries, diseases, and congenital defects.

Sinus CT Scan

Purpose: Detect inflammatory diseases, plan surgery, evaluate fluid-filled sinuses, and diagnose sinusitis.
Scout Image: Patient supine, scan perpendicular to hard palate.
Contrast: 100cc Omnipaque 300 IV contrast medium.
Parameters: kVp/Effective mAs/Rotation Time (sec): 120/130/0.75, FOV: 180 mm, Thickness: 3 mm.
Windows: Bone: WC:200, WW:2000; Soft Tissue: WC:50, WW:350.

Temporal Bone CT Scan

Purpose: Evaluate outer ear, ear bones, inner ear structures for infection, tumors, injuries, and hearing disorders.
Scout Image: Patient supine, scan parallel to orbitomeatal line.
Contrast: 100cc Omnipaque 300 IV, assess for malignant lesions with contrast.
Parameters: kVp/Effective mAs/Rotation time (sec): 120/160/1.0
Reconstruction Filter: Ultra High Bone Algorithm
Thickness: 1 mm
Resolution: High
Windows: Bone: WC: 400, WW: 4000; Soft Tissue: WC: 50, WW: 350

Facial Bones CT Scan

Purpose: Diagnose facial trauma and malformations.
Scout Image: Patient supine.
Parameters: Thin slices, (2-3.5 mm)
Windows: Bone: WC: 200, WW: 2000; Soft Tissue: WC: 50, WW: 350

Orbital CT Scan

Purpose: Diagnose eye and orbital socket injuries, diseases and congenital defects.
Scout Image: Patient supine.
Contrast: 100cc Omnipaque 300 IV, rule out infections/abscesses, orbital tumors, and optic atrophy.
Parameters: kVp/Effective mAs/Rotation Time (sec): 120/170/0.75
Resolution: High
Windows: Bone: WC: 200, WW: 2000; Soft Tissue: WC: 50, WW: 350

Scan Coverage

Sinuses: Maxillary teeth through frontal sinuses, set up to start posterior to the sphenoid sinus, continued anteriorly.
Temporal Bones: Above Petrous ridges to tip of mastoids, set up to start at the top of the anterior arch of C1, continue superiorly to the roof of the mastoid air cells.
Mandible: Below the Mandible through Frontal Sinuses, set up to start below the mandible, continue superiorly through frontal sinuses.

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Description

This quiz covers the essential computed tomography (CT) procedures for imaging sinuses, facial bones, and temporal bones. You will learn about the applications of CT scans in diagnosing diseases and conditions such as sinusitis, tumors, and hearing disorders. Test your knowledge on parameters, techniques, and the importance of scout images.