PARIS — For the diagnosis of giant cell arteritis, cranial ultrasound is more sensitive than temporal artery biopsy, new research shows.
"Giant cell arteritis can cause serious problems but is very treatable with steroid therapy. The key is early diagnosis and initiation of treatment," said lead investigator Adam Croft, PhD, from the Centre for Translational Inflammation Research at the University of Birmingham in the United Kingdom.
"Temporal artery biopsy has been considered the gold standard for diagnosis," he said. However, the invasive procedure is associated with facial nerve injury and can injure the artery. Although it is a specific test, it has a low sensitivity and a false-negative rate of 20%.
"The exciting results of this study suggest that cranial ultrasound may soon replace invasive biopsy for the first-line assessment of patients with a suspected diagnosis of giant cell arteritis in routine clinical practice," Dr. Croft explained.
"Temporal artery biopsy can miss the diagnosis. We are not usually reassured by a negative biopsy. We propose ultrasound as an alternative method for making the diagnosis early," he said.
He presented the results here at the European League Against Rheumatism (EULAR) Congress 2014.
The 87 patients with suspected giant cell arteritis underwent cranial ultrasound from January 2005 to July 2013. At 3-month follow-up, 36 patients had a confirmed diagnosis.
Of the 30 patients with positive results on cranial ultrasound, 29 had a confirmed diagnosis of arteritis at 3 months.
Ultrasound was the strongest predictor of a confirmed diagnosis. In fact, the chance of having a positive diagnosis was 41 times higher with ultrasound than it was with temporal artery biopsy, Dr. Croft reported.
Table. Performance of the 2 Diagnostic Tests
| Measure | Cranial Ultrasound, % | Temporal Artery Biopsy, % |
| Sensitivity | 81 | 53 |
| Specificity | 97 | 100 |
| Positive predictive value | 97 | 100 |
| Negative predictive value | 88 | 47 |
"The high positive and negative predictive value of ultrasound indicates that biopsy could be avoided where the clinical suspicion of giant cell arteritis is either high or low," he continued.
The current EULAR guidelines suggest that ultrasound can be used as a diagnostic tool for giant cell arteritis. Dr. Croft believes that the guidelines will strengthen this recommendation in the future.
However, he cautioned, ultrasound requires that people be well trained and have the expertise to make a diagnosis. "You need to have the infrastructure to do the scan rapidly. If you can't do it rapidly, you may need to perform temporal artery biopsy instead," he said.
A Reliable Tool for Routine Use
This is an important and potentially practice-changing study, said Maya Buch, MD, from the Leeds Institute of Rheumatology and Musculoskeletal Diseases in the United Kingdom.
"The study addressed the clinical needs for patients with giant cell arteritis," she told Medscape Medical News. "With further study, this should become a reliable tool for routine use in clinical practice."
"I am sure we will be hearing more about this in the coming years," she said.
Dr. Croft has disclosed no relevant financial relationships. Dr. Buch reports financial relationships with AbbVie, Bristol-Myers Squibb, Roche-Chugai, and Pfizer.
European League Against Rheumatism (EULAR) Congress 2014: Abstract OP0056. Presented June 12, 2014.
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Cite this: Ultrasound Better Than Biopsy in Giant Cell Arteritis - Medscape - Jun 14, 2014.
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