High-resolution computed tomography

June, 2018

Exam: CT Thorax for interstitial lung disease

Protocol:
- Oral Contrast: none
- IV Contrast: none

- Acquisitions:

1) Supine, Inspiration


Breathing instructions for inspiratory scout and CT acquisition:
“For the first part of this study I am going to give you specific breathing instructions. Try to follow as best you can.”
“Take in a deep breath….and let it out.”
“Take in another deep breath….and let it out.”
“Take in another deep breath, and hold your breath in. Keep holding your breath!”


Scout views: PA and Lateral to include all of chest
Scan Range: Lung apices to base

Inspiratory CT acquisition parameters

Detector Collimation

 

kV

mAs

Pitch

Rotation

Tube current modulation

 

Helical 1.2mm

120 (may be lower as tolerated by interpreting physician

230 (may be lower as tolerated by interpreting physician

~1.0

0.5sec (or faster)

on


Image reconstruction parameters

Image Processing Plane

 

Field of view

Reconstruction algorithm

Slice reconstruction thickness

 

Slice reconstruction interval

 

Window

Source

Axial

Variable

Soft tissue (e.g. Siemens B31f, GE standard, Philips B, Toshiba Body Std.)


3 mm

3 mm

Mediastinum

raw

Axial thin section

≤ 2 cm beyond lung margin

Moderate edge- enhancing algorithm (e.g. Siemens B45f, GE Bone, Philips D or YB, Toshiba lung std.)

1 mm

1 mm

Lung

raw


Optional Axial thick section

≤ 2 cm beyond lung margin

Moderate edge- enhancing algorithm (e.g. Siemens B45f, GE Bone, Philips D or YB, Toshiba lung std.)

 

3 mm

3 mm

Lung

raw

Axial MIP

≤ 2 cm beyond lung margin

Moderate edge- enhancing algorithm (e.g. Siemens B45f, GE Bone, Philips D or YB, Toshiba lung std.)

 

6 mm

3 mm

Lung

raw

Coronal

≤ 2 cm beyond lung margin

Moderate edge- enhancing algorithm (e.g. Siemens B45f, GE Bone, Philips D or YB, Toshiba Lung Std.)

2.5 mm

2.5 mm

Lung

raw

Sagittal

≤ 2 cm beyond lung margin

Moderate edge- enhancing algorithm (e.g. Siemens B45f, GE Bone, Philips D or YB, Toshiba Lung Std.)

 

2.5 mm

2.5 mm

Lung

raw


* Technologist must review scans immediately after acquisition and repeat as appropriate if there is motion artifact or inadequate inspiration (in clearly non-diagnostic cases) or must contact a radiologist immediately while the patient is on the scanner gantry to determine whether repeating or adding any additional scans is necessary. Also perform prone scans if there is dependent density on supine images.

2) Supine, Expiration

Breathing instructions for expiratory scout and CT acquisition:
“For the next part of this study we will ask you to breathe out and hold your breath.”
“Take in a deep breath….and let it out.” “Take in another deep breath….and let it out.”
“Take in another deep breath, let it out and hold your breath out! Do not breathe!”
Scout views: PA and Lateral to include all of chest
 
Scan Range
2cm below lung apices to base

Expiratory CT acquisition parameters

Detector collimation

 

kV

mAs

Scan interval

 

rotation

Tube current modulation

 

Axial 2 x 1.0mm

120

150

20 mm

1.0 sec

on


* Technologist must review scans immediately after acquisition and repeat as appropriate if there is motion artifact or inadequate expiration.

Image reconstruction parameters

Image Processing Plane

 

Field of view

 

Reconstruction algorithm

Slice reconstruction thickness

 

Slice reconstruction interval

 

Window

Source

Axial thin section

≤ 2 cm beyond lung margin

Moderate edge- enhancing algorithm (e.g. Siemens B45f, GE Bone, Philips D or YB, Toshiba Lung Std.)

 

2 mm

20 mm

Lung

raw

3) Prone, Inspiration (do this series only if dependent density noted on HRCT)

Breathing instructions for prone inspiratory scout and CT acquisition:

“Take in a deep breath….and let it out.” “Take in another deep breath….and let it out.”
“Take in another deep breath, and hold your breath in. Keep holding your breath!”


Scout views: PA and Lateral to include all of chest
Scan Range: Carina to lung base
Prone Inspiratory CT acquisition parameters

Detector Collimation

kV

mAs

Scan interval

 

rotation

Tube current modulation

 

Axial 2 x 1.0mm

 

120

150

20 mm

1.0 sec

on


Image reconstruction parameters

Image Processing Plane

 

Field of View

 

Reconstruction algorithm

Slice reconstruction thickness

 

Slice reconstruction interval

 

Window

Source

Axial thin section

≤ 2 cm beyond lung margin

Moderate edge- enhancing algorithm (e.g. Siemens B45f, GE BonePhilips D or YB, Toshiba Lung Std.)

2 mm

20 mm

Lung

raw


* Technologist must review scans immediately after acquisition and repeat as appropriate if there is motion artifact or inadequate inspiration.

 

footer_txt_bblBook a PFF Ambassador for your event.   Call 844.TalkPFF >