Ultrasound shows potential for early diagnosis of large vessel giant cell arteritis
medwireNews: Vascular ultrasound could be a contender as a first-line imaging test for diagnosing large vessel giant cell arteritis (GCA), suggests research.
Presenting the findings at the 2018 ACR/ARHP Annual Meeting in Chicago, Illinois, USA, Berit Dalsgaard Nielsen, from Aarhus University Hospital in Denmark, highlighted the potential of this type of imaging given its “availability and its low price” and the fact that it does not require patient preparation. But she acknowledged that not all blood vessels can be assessed using this technique, which is possible with the more expensive and less readily available positron emission tomography (PET) scan.
Nielsen and team screened 102 patients with suspected GCA prior to glucocorticoid treatment and included in their trial the 90 who were aged 50 years or older, had C-reactive protein levels above 15 mg/L or an erythrocyte sedimentation rate above 40 mm/hour, and cranial symptoms, new-onset claudication, protracted constitutional symptoms, or polymyalgia rheumatica symptoms.
Of these, 42 were diagnosed with large vessel GCA and concomitant cranial GCA, four with isolated large vessel GCA, and 10 with isolated cranial GCA based on clinical diagnosis and an 18F-fluorodeoxyglucose (FDG)-PET/computed tomography that showed aortic and/or subclavian/axillary artery FDG uptake over liver uptake. The remaining 34 patients without GCA formed a control group.
Ultrasounds of the carotid arteries of the neck and the axillary arteries under the arm were carried out by a sonographer blinded to the PET results.
They found that 78% of patients with confirmed large vessel GCA also tested positive on ultrasound and these patients could be diagnosed with 100% specificity, as none of the patients in the control group had a positive axillary ultrasound result.
These patients also had temporal arteries evaluated, which alone identified 73% of the 46 patients with large vessel GCA, but if ultrasound assessment of the large arteries was also included, this increased to 91%, with a specificity of 97% in both cases.
Nielsen noted that agreement between the sonographers was “almost perfect,” at 90% for the large vessels and 83% for temporal arteries.
“These results implicate that ultrasound should not only be a first-line imaging test in patients presenting with cranial symptoms, but also patients suspected of GCA presenting with constitutional symptoms,” she recommended.
“And if this examination is included in the standard examinations in the fast track clinics it may overcome the delay in diagnosis and patients can be treated earlier,” and may spare them from unneeded examinations.
By Lucy Piper
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