Lecler et al reported an algorithm for the imaging diagnosis of Giant Cell Arteritis (GCA). The authors are from multiple institutions in Paris.
Patient selection: suspected giant cell arteritis (GCA)
EULAR guidelines allow confirmation of GCA by one or more of the following:
(1) ultrasonography
(2) MRI
(3) CT
(4) PET
(5) histology
Protocol: MRI followed by ultrasound and/or retinal angiography
|
MRI Result
|
Secondary Imaging
|
Diagnosis for GCA
|
|
positive
|
NA
|
positive
|
|
indeterminate
|
positive
|
positive
|
|
indeterminate
|
negative
|
negative
|
|
negative
|
NA
|
negative
|
Arterial segments visualized on MRI:
(1) left frontal branches of superficial temporal artery
(2) right frontal branches of superficial temporal artery
(3) left parietal branches of superficial temporal artery
(4) right parietal branches of superficial temporal artery
(5) left occipital artery
(6) right occipital artery
Positive ultrasonography findings - one or both of the following
(1) halo sign
(2) thickened arterial wall in temporal arteries
Positive retinal angiography findings:
(1) delay in choroidal vessel filling on fluorescein angiography (patchy choroidal vessel filling that persists until retinal venous phase was considered pathologic)
(2) presence of non-vascularized choroidal areas o indocyanine green angiography
(3) abnormalities in retinal pigment epithelium in late phase imaging
