The Giant Cell Arteritis (GCA) Halo score is determined by measuring thickness of various arterial segments using ultrasonography.
Patient selection: giant cell arteritis
Measurement by ultrasonography: thickness of the largest halo in the arterial segment
Arteries:
(1) right temporal artery
(1a) common superficial (CSTA)
(1b) parietal (PTA)
(1c) frontal (FTA)
(2) left temporal artery
(2a) common superficial
(2b) parietal
(2c) frontal
(3) right axillary artery (AA)
(4) left axillary score
|
CSTA
|
PTA
|
FTA
|
AA
|
Grade
|
|
<= 0.3 mm
|
<= 0.2 mm
|
<= 0.1 mm
|
<= 0.5 mm
|
0
|
|
0.4
|
0.3
|
0.2
|
0.6
|
1
|
|
0.5
|
0.4
|
0.3
|
0.7 to 0.8
|
2
|
|
0.6 to 0.7
|
0.5
|
0.4
|
0.9 to 1.5
|
3
|
|
>= 0.8 mm
|
>= 0.6 mm
|
>= 0.5 mm
|
>= 1.6 mm
|
4
|
temporal artery halo score =
= SUM(points for all grades)
axillary artery halo score =
= 3 * ((points for left AA) + (points for right AA))
total halo score =
= (temporal artery halo score) + (axillary artery halo score)
Interpretation:
• minimum scores: 0
• maximum temporal artery halo score: 24
• maximum axillary artery halo score: 24
• maximum total halo score: 48
• The higher the score the greater the risk of GCA and the greater the risk of complications
A modified halo score includes the axillary artery together with the axillary artery on both sides.
