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This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Beer, A. Articles by Schwaiger, M. PubMed Articles by Beer, A. Articles by Schwaiger, M.

Imaging of vβ3 in human carotid plaques by [18F]galacto-RGD PET/CT

¹ Nuclear Medicine; ² TU Munich, Munich, Germany

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Objectives: Neovascularization substantially contributes to plaque vulnerability. As the integrin vβ3 is a key player in angiogenesis, we evaluated, if imaging of vβ3 in carotid plaques in patients is feasible with [18F]Galacto-RGD PET/CT.

Methods: 9 patients with carotid stenosis were examined preoperatively before endarterectomy with PET/CT 90 min. after injection of [18F]Galacto-RGD. SUVs were derived over the plaques or in case of no stenosis, over the carotid bifurcation using CT for anatomic correlation (n=18). Blood pool activity was measured in the common carotid artery. Stenosis-to-blood (S/B) ratios were correlated with the degree of stenosis (scaled from 0 to 4) and with the flow velocity (Vmax) in Doppler ultrasound. The resection specimens were examined immunohistochemically for vβ3 expression (LM609), neovascularization (CD31) and macrophage infiltration (CD68).

Results: [18F]Galacto-RGD PET/CT demonstrated elevated tracer uptake in stenotic sites (SUV 1.5+/-0.2; range 1.2-1.9) compared to blood pool (mean SUV 1.2+/-0.2; range 0.7-1.7). S/B ratios in high grade stenosis (grade 2-4) were significantly higher (26+/-17%) compared to none or low grade stenosis (10+/-5%; p=0.04) and were significantly higher in lesions with Vmax >150 cm/sec (29+/-17% versus 8+/-4%; p=0.01). No difference was found between symptomatic and asymptomatic lesions (p=0.70). Immunohistochemistry demonstrated elevated levels of neovascularization and macrophage infiltration in plaques with pronounced tracer uptake, with vβ3 found on endothelial cells as well as macrophages.

Conclusions: [18F]Galacto-RGD PET/CT can identify elevated levels of vβ3 in highly vascularized, inflammatory carotid plaques in patients. Future studies will show, if this information is of prognostic relevance concerning plaque vulnerability and neurologic symptoms.

This Article Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Beer, A. Articles by Schwaiger, M. PubMed Articles by Beer, A. Articles by Schwaiger, M.