An observational study in Giant Cell Arteritis, Anterior Ischemic Optic Neuropathy and Optic Neuropathy, Ischemic, sponsored by Centre Integre Universitaire de Sante et Services Sociaux du Nord de l'ile de Montreal. Recruiting at 7 sites in Canada. Open to participants aged 50 Years to 99 Years. Per ClinicalTrials.gov, last updated 2026-10-21.
Sponsored by Centre Integre Universitaire de Sante et Services Sociaux du Nord de l'ile de Montreal · Observational
The Sonographic Assessment of the Optic Nerve Sheath in Giant Cell Arteritis (SONIC-GCA) study will evaluate the performance of the optic nerve sheath diameter (ONSD), measured via ultrasound, to diagnose and monitor GCA. SONIC-GCA builds upon our previous pilot studies and will answer the following questions:
SONIC-GCA is a prospective cohort and validation study conducted in centers of the Canadian Vasculitis Research Network (CanVasc).
147 studies on the registry are indexed under Giant Cell Arteritis; 49 are open to participants now.
This study's planned enrollment of 285 is above the median of 128 across 78 observational studies indexed under Giant Cell Arteritis.
Browse Giant Cell Arteritis studies →Centre Integre Universitaire de Sante et Services Sociaux du Nord de l'ile de Montreal is the lead sponsor of 34 studies on the registry; 16 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Consecutive participants referred for suspected new-onset GCA.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Our population of interest is patients referred from any settings for suspected, new-onset GCA.
Inclusion criteria:
To be included in SONIC-GCA, participants must meet all the following criteria:
Exclusion criteria:
An individual who meets any of these criteria will be excluded from SONIC-GCA:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Ascertainment of GCA will occur 6 months after study inclusion and will require all the following features: 1) initial symptoms and clinical evolution consistent with GCA; 2) at least one positive diagnostic test for GCA, including ultrasound of temporal arteries, temporal artery biopsy, cranial MRI or cranial PET; and 3) satisfies the 2022 ACR-EULAR classification criteria for GCA. Study visits : Baseline - Month 3, 6, 12, 18 and 24 + relapse visit (if applicable)
Diagnostic Test: Optic nerve sheath ultrasound · Diagnostic Test: Standardized GCA assessment
Participants who do not meet the composite clinical test validation for GCA (above). Study visits : Baseline and Month 6 (phone follow-up)
Diagnostic Test: Optic nerve sheath ultrasound · Diagnostic Test: Standardized GCA assessment
The patients are examined in a supine relaxed position. The probe is gently placed on the closed eyelid with a standard ultrasound gel and adjusted to a suitable angle to display the optic nerve entry into the eyeball. Measurements are done 3mm distal to the posterior aspect of the ocular globe. Ultrasosonographic 14L5 probe is used with a safe thermal index, mechanical index and intensity limit. All patients will also undergo a bedside fundoscopic examination. Official ophthalmology consultation will be requested in patients with visual symptoms or abnormal fundoscopy.
Clinical assesment, blood test review, temporal/axillary artery ultrasound
Diagnostic performance of ONSD to identify new-onset GCA
The primary outcome of SONIC-GCA is to determine the optimal ONSD cutoff for identifying GCA at the baseline visit and to assess its diagnostic performance, including sensitivity, specificity, positive and negative predictive values, and accuracy.
Time frame: Baseline
ONSD in patients with and without GCA
At baseline, ONSD measurements (in mm) of the left and right eyes of each participant will be recorded and used to calculate the mean ONSD for patients with and without GCA.
Time frame: Baseline
ONSD changes over time
The main secondary outcome will determine whether ONSD dynamically correlates with relapse risk over the follow-up period in patients with GCA, providing insight into its potential as a biomarker for disease monitoring.
Time frame: Up to 2 years
The associations between ONSD changes and GCA relapses
The association between ONSD changes and GCA relapses will be assessed during the follow-up period, in patients with GCA.
Time frame: Up to 2 years
Evaluation of the performance of ONSD to detect a GCA relapse
We will assess the diagnostic performance of the initial ONSD cutoff (from the primary objective) at each follow-up visit to differentiate between relapse and remission. This analysis will determine whether the established cutoff remains a reliable marker for monitoring disease status in GCA over time.
Time frame: Up to 2 years
Intra- and Inter- observer reliability
Intra- and interobserver reliability of ONSD measurements
Time frame: Baseline
Association between ONSD and Retinal Changes
The association between ONSD and the presence/absence of GCA-related retinal findings on digital fundoscopy in patients with GCA.
Time frame: Up to 2 years
Plan to share: No
Started Aug 2025 (actual). Primary completion is estimated for Dec 2027, 28 months after the start.
Of 44 observational studies under Giant Cell Arteritis, half reached primary completion within 45 months of starting (the median), counting those still running; a quarter within 33 and three quarters within 164. This study's planned 28 months is below that.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Centre Integre Universitaire de Sante et Services Sociaux du Nord de l'ile de Montreal