Diagnostic yield of combined cranial and large vessel PET/CT, ultrasound and MRI in giant cell arteritis: A systematic review and meta-analysis.

Objectives: To estimate the diagnostic accuracy of combined cranial and large vessel imaging by PET/CT, ultrasound and MRI for giant cell arteritis (GCA).

Methods: PubMed, Embase, Cochrane and Web of Science databases were searched from inception till August 31, 2022. Studies were included if they involved patients with suspected GCA and assessed the diagnostic accuracy of combined cranial and large vessel imaging by PET/CT, ultrasound or MRI with the final clinical diagnosis as reference standard.

Results: Eleven (1578 patients), 3 (149 patients) and 0 studies were included for the diagnostic accuracy of ultrasound, PET/CT and MRI, respectively. Combined cranial and large vessel ultrasound had a sensitivity of 86% (76-92%) and specificity of 96% (92-98%). PET/CT of both cranial and large vessels yielded a sensitivity of 82% (61-93%) and specificity of 79% (60-90%). No studies assessed both PET/CT and ultrasound, which precluded head-to-head comparison. Addition of large vessel ultrasound to ultrasound of the temporal arteries (7 studies) significantly increased sensitivity (91% versus 80%, p < 0.001) without decrease in specificity (96% versus 95%, p = 0.57). Evaluating cranial arteries in addition to large vessels on PET/CT (3 studies) tended to increase the sensitivity (82% versus 68%, p = 0.07) without decrease in specificity (81% versus 79%, p = 0.70).

Conclusion: Combined cranial and large vessel ultrasound and PET/CT provided excellent accuracy for the diagnosis of GCA. Either PET/CT or ultrasound may be preferred depending on setting, expertise and clinical presentation. The diagnostic accuracy of combined cranial and large vessel MRI needs to be determined in future studies.