CT TEMPORAL BONES

INDICATIONS: WithOut: Cholesteatoma, tinnitus, hearing loss, otalgia, otitis media

With: Tumor, unable to have MRI

PATIENT PREP: WithOut: No Prep

With: NPO for solid foods, water only, for 4 hours prior to scan

IV CONTRAST: Perform as directed by the supervising radiologist.

WithOut: None

With: 80mL Isovue 370 @ 2.0 mL/second.

ORAL CONTRAST: None

POSITIONING: Head First Supine. Position head to superimpose the base of the skull and acanthion.

TOPOGRAMS: AP. Range: Above petrous bone through mastoid tips. 25 mA, 110 kV.

Lateral. Range: Above petrous bone through mastoid tips. 25 mA, 110 kV.

SCAN TYPE: Spiral/Helical

NOTES: Scan Bilateral Ears and send Bilateral Axials to PACs. Then reconstruct each ear separately andsend to PACs.

CT Temporal Bones usually performed Without contrast. On rare occasions, if referring physician orders With and WithOut contrast, our

Radiologists usually say to perform the exam just With contrast in order to reduce the radiation dose.Check with the Radiologist. If exam performed

both With and WithOut contrast,PerformJust the Axial Bone reformations on the Noncontrast scan, but perform ALL of the reconstructions on the

With Contrast scan.

ALARA – Keep radiation dose As Low As Reasonably Achievable.

TEMPORAL BONES - WITHOUT

Scan
Range / ScanDirection
Scan Type / Respiration / Scan
Delay
(Seconds) / CARE
DOSE
4D / Effective
mAs / kV / Detector Configuration
Slices Per Tube Rotation / Pitch
Table Increment/Speed:(mm/rotation) / Rotation
Time
(Seconds) / SFOV
(cm)
Top of petrous
Bonethrough Mastoidtips / Craniocaudal
Spiral/Helical / Quiet
Respiration / 3
Seconds / OFF / 130 / 130 / Detectors: 4 x 0.6 mm
Slices Per Tube Rotation: 4 / Pitch: 0.45
Table Increment/Speed: 1.08 mm/rotation / 1.0
Seconds / 30
cm
Plane / Slice
Thickness / Interval / Kernal / Window
Width/Level / DFOV
(cm)
RECON – SEND TO PACS
Axial Bilateral Ears-Bone / Axial Bilateral Ears: Top of petrous bonethrough mastoid tips.
Position patient to superimposebase of skull and acanthion / 0.6 mm / 0.3 mm / H70s
Sharp FR / Osteo
1500/450 / 18
cm
RECON
Axial Right Ear-Bone / Axial Right Ear: Top of petrous bonethrough mastoid tips.
Position patient to superimposebase of skull and acanthion / 0.6 mm / 0.3 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Axial Left Ear-Bone / Axial Left Ear: Top of petrous bonethrough mastoid tips.
Position patient to superimposebase of skull and acanthion / 0.6 mm / 0.3 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Coronal Right Ear-Bone / Coronals Right Ear: Mandibular condyles through mastoid.
Perpendicular to petrous bone / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Coronal Left Ear-Bone / Coronals Left Ear: Mandibular condyles through mastoid.
Perpendicular to petrous bone / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Sagittal Right Ear-Bone / Sagittals Right Ear: Auricle through Right Temporal Bone.
Straight Sagittal / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Sagittal Left Ear-Bone / Sagittals Left Ear: Auricle through Left Temporal Bone.
Straight Sagittal / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Stenvers Right Ear -Bone / Stenvers Right Ear: Parallel to the Axis of the Temporal Bone.
Perpendicular to the Course of the Superior Semicircular Canal. / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Stenvers Left Ear -Bone / Stenvers Left Ear: Parallel to the Axis of the Temporal Bone.
Perpendicular to the Course of the Superior Semicircular Canal. / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Poschl Right Ear - Bone / Poschl Right Ear: Perpendicular to the Long Axis of the Temporal Bone.
Parallel to the Course of the Semicircular Canal. / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/4500 / 10
cm
RECON
Poschl Left Ear - Bone / Poschl Left Ear: Perpendicular to the Long Axis of the Temporal Bone.
Parallel to the Course of the Semicircular Canal. / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm

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TEMPORAL BONES - WITH

Scan
Range / ScanDirection
Scan Type / Respiration / Scan
Delay
(Seconds) / CARE
DOSE
4D / Effective
mAs / kV / Detector Configuration
Slices Per Tube Rotation / Pitch
Table Increment/Speed: (mm/rotation) / Rotation
Time
(Seconds) / SFOV
(cm)
Top of petrous
Bonethrough Mastoid tips / Craniocaudal
Spiral/Helical / Quiet
Respiration / 60 Seconds / OFF / 130 / 130 / Detectors: 4 x 0.6 mm
Slices Per Tube Rotation: 4 / Pitch: 0.45
Table Increment/Speed: 1.08 mm/rotation / 1.0
Seconds / 30
cm
Plane / Slice
Thickness / Interval / Kernal / Window
Width/Level / DFOV
(cm)
RECON – SEND TO PACS
Axial Bilateral Ears-Bone / Axial Bilateral Ears: Top of petrous bonethrough mastoid tips.
Position patient to superimposebase of skull and acanthion / 0.6 mm / 0.3 mm / H70s
Sharp FR / Osteo
1500/450 / 18
cm
RECON
Axial Right Ear-Soft Tissue / Axial Right Ear: Top of petrous bonethrough mastoid tips.
Position patient to superimposebase of skull and acanthion / 0.6 mm / 0.3 mm / U40u
Medium / Mediastinum
400/40 / 10
cm
RECON
Axial Left Ear-Soft Tissue / Axial Left Ear: Top of petrous bonethrough mastoid tips.
Position patient to superimposebase of skull and acanthion / 0.6 mm / 0.3 mm / U40u
Medium / Mediastinum
400/40 / 10
cm
RECON
Axial Right Ear-Bone / Axial Right Ear: Top of petrous bonethrough mastoid tips.
Position patient to superimposebase of skull and acanthion / 0.6 mm / 0.3 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Axial Left Ear-Bone / Axial Left Ear: Top of petrous bonethrough mastoid tips.
Position patient to superimposebase of skull and acanthion / 0.6 mm / 0.3 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Coronal Right Ear-Bone / Coronals Right Ear: Mandibular condyles through mastoid.
Perpendicular to petrous bone / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Coronal Left Ear-Bone / Coronals Left Ear: Mandibular condyles through mastoid.
Perpendicular to petrous bone / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Sagittal Right Ear-Bone / Sagittals Right Ear: Auricle through Right Temporal Bone.
Straight Sagittal / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Sagittal Left Ear-Bone / Sagittals Left Ear: Auricle through Left Temporal Bone.
Straight Sagittal / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Stenvers Right Ear -Bone / Stenvers Right Ear: Parallel to the Axis of the Temporal Bone.
Perpendicular to the Course of the Superior Semicircular Canal. / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Stenvers Left Ear -Bone / Stenvers Left Ear: Parallel to the Axis of the Temporal Bone.
Perpendicular to the Course of the Superior Semicircular Canal. / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm
RECON
Poschl Right Ear - Bone / Poschl Right Ear: Perpendicular to the Long Axis of the Temporal Bone.
Parallel to the Course of the Semicircular Canal. / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/4500 / 10
cm
RECON
Poschl Left Ear - Bone / Poschl Left Ear: Perpendicular to the Long Axis of the Temporal Bone.
Parallel to the Course of the Semicircular Canal. / 1.0 mm / 1.0 mm / H70s
Sharp FR / Osteo
1500/450 / 10
cm

*The operator must check the CTDIvol before and after the scan to ensure it is within the allowed dose range. Scans performed outside of the allowed range must be

documented and reviewed by the designated radiologist and/or physicist.

Allowed CTDIvol Dose Ranges:4 mGy – 60 mGy

XR29 Dose Notification Value (CTDIvol):60 mGy

NETWORK:Exam to PACS

Page 2 of 3

STENVERS REFORMATIONPOSCHL REFORMATION

Parallel to the Axis of the Temporal Bone.Perpendicular to the Long Axis of the Temporal Bone.

Perpendicular to the Course of the SuperiorParallel to the Course of the Semicircular Canal.

Semicircular Canal.

12/2017Page 3 of 3