Positron emission tomography and computed tomography angiography for the diagnosis of giant cell arteritis

Abstract

The use of 18F-fluoro-deoxyglucose positron emission tomography scan (FDG-PET) and computed tomography angiography (CTA) to improve accuracy of diagnosis of giant cell arteritis (GCA) is a very important clinical need. We aimed to compare the diagnostic performance of FDG-PET and CTA in patients with GCA.FDG-PET and CTA were acquired in all consecutive patients suspected for GCA. Results of FDG-PET and CTA were compared with the final diagnosis based on clinical judgment, temporal artery biopsy (TAB) findings, and ACR criteria. Sensitivity, specificity, and positive and negative predictive values (PPV, NPV) were calculated for each method.Twenty-four patients suspected for GCA were included. Fifteen (62.5%) were ultimately diagnosed as having GCA. Among them, all fulfilled ACR criteria and 6 had biopsy-proven GCA. Strong FDG uptake in large vessels was found in 10 patients who all had GCA. Mean maximal standard uptake values (SUVmax) per patient measured at all the arterial territories were of 3.7 (range: 2.8–4.7). FDG uptake was negative in 14 patients including 9 and 5 patients without and with GCA, respectively. Mural thickening suggestive of aortitis or branch vessel arteritis was observed on CTA in 11 patients with and 2 patients without GCA. No mural thickening was observed in 11 patients including 7 patients without and 4 patients with GCA. Overall, sensitivity was 66.7% and 73.3%, specificity was 100% and 84.6%, NPV was 64.3% and 64.6%, and PPV was 100% and 84.6% of FDG-PET and CTA, respectively.Both FDG-PET and CTA have a strong diagnostic yield for the diagnosis of GCA. FDG-PET appeared to have a higher PPV as compared to CTA and may be the preferred noninvasive technique to explore patients with suspected GCA.

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“…One study found 18F-fluoro-deoxyglucose uptake by large vessels yielded a sensitivity of 66.7% and a specificity of 100% for giant cell arteritis diagnosis 11. However, these patients either had a known diagnosis of the condition or were already suspected of having it.…”

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“…PET/CT is also a useful diagnostic tool for evaluating GCA. PET/CT is known to have a sensitivity of 89.5% and a specificity of 97.7% in GCA diagnoses 11) . Typically, the diagnosis of GCA was based on the presence of high FDG uptake in the vascular wall of the aorta, the supra-aortic branches, and the vertebral, iliac, and femoral arteries 11) .…”

“…Typically, the diagnosis of GCA was based on the presence of high FDG uptake in the vascular wall of the aorta, the supra-aortic branches, and the vertebral, iliac, and femoral arteries 11) . In GCA patients, CT angiography has proven to be effective in showing aortitis, which is characterized by thickening of the vessel wall, inflammatory periaortic soft tissue change, stenosis, or aneurysm 11) . Shoulder pain is a common problem in the elderly.…”

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“… Data on computed tomography angiography (CTA) were from 1 study, using clinical diagnosis as the reference standard . …”