Introduction: This study aims to evaluate the use of PET/CT compared with temporal artery biopsy (TAB) as a diagnostic tool in patients suspected of giant cell arteritis (GCA) and to determine the influence of glucocorticoid treatment on diagnostic performance.
Methods: This was a retrospective cohort study; 191 patients booked for TAB during a five-year period were screened for inclusion. The study population was divided into two groups. A TAB group containing patients who completed only TAB to assess potential selection bias and a PET/CT + TAB group containing patients with TAB and PET/CT to evaluate the diagnostic performance. The clinical diagnosis of GCA was established after a follow-up period of minimum six months.
Results: A total of 157 patients were included in the study: 77 patients in the TAB group and 80 patients in the PET/CT + TAB group. The result of TAB and PET/CT did not match in 15 cases. Overall, the negative agreement rate of TAB and PET/CT was 19% (95% confidence interval (CI): 11-29%). The sensitivity of PET/CT was 76% (95% CI: 63-90%) compared with the clinical diagnosis. The sensitivity of TAB was lower: 63% (95% CI: 48-78%), but not significantly different (z = 1.26/p = 0.2). The sensitivity of both PET/CT and TAB increased to 85% (95% CI: 72-99%) and 74% (95% CI: 58-91%) if performed within three days of glucocorticoid therapy.
Conclusion: This study strengthens the evidence that conventional PET/CT is a useful imaging modality in the diagnosis of the entire spectrum of GCA, including the assessment of both cranial and extra-cranial arteries.
Funding: None.
Trial registration: Not relevant.
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