Acquisition Phase

Phase Included

Scan Delay

Respiration Phase

Anatomical Coverage

Non Contrast

Yes

N/A

N/A

To include mastoid air cells through petrous ridges

Arterial Phase

 N/A

N/A

N/A

N/A

Venous Phase

 N/A

N/A

N/A

N/A

Delayed Phase

 N/A

N/A

N/A

N/A

Scan Comments: Careful positioning is important to avoid unnecessary exposure to the eyes. All scans are performed using the ALARA principle.

 

Technical Parameters

Parameters

kVp

Care kV (ref. kV 120)

Effective mAs

CareDose

Care Dose Reference mAs

230

Time (Rotation)

1.0 sec

Average Acquisition Time

10 sec

Collimation

16 x 0.3mm

Pitch Value

0.85

Scan Direction

Caudocranial

Comments: Decreasing the display field of view for both the right and the left temporal bones will increase spatial resolution. Scan times are significantly longer than routine scans due to a small collimator size coupled with a low pitch value to increase resolution. CareDose is used to limit patient exposure.

 

Reconstruction Parameters

Soft Tissue

Thin Data

Bone

Slice Thickness

2mm

0.4mm

0.5mm

Reconstruction Spacing

2mm

0.4mm

0.5mm

Reconstruction Algorithm

U30u

U70u

U70u

Window Width and Level

350/20

2500/500

2500/500

Reconstruction Comments:  Reconstructions are done both bilaterally and coned down for each temporal bone. Coronal image reconstructions are also performed.

 

Contrast Parameters

Parameters

Contrast Type

 N/A

Contrast Volume

 N/A

Saline Flush

 N/A

Injection Rate

 N/A

Oral Contrast

 N/A

Contrast Volume

 N/A

Comments: IV contrast is not typically necessary for this exam.