PETCT Imaging of Unstable Carotid Plaque with Ga-68 labelled Somatostatin Receptor Ligand.

Wan, Ming Young Simon; Endozo, Raymond; Michopoulou, Sofia; Shortman, Robert; Rodriguez-Justo, Manuel; Menezes, Leon; Yusuf, Syed; Richards, Toby; Wild, Damian; Waser, Beatrice; Reubi, Jean Claude; Groves, Ashley (2017). PETCT Imaging of Unstable Carotid Plaque with Ga-68 labelled Somatostatin Receptor Ligand. Journal of nuclear medicine, 58(5), pp. 774-780. Society of Nuclear Medicine 10.2967/jnumed.116.181438

Text petct_imaging_of_unstable_carotid.pdf - Accepted Version Restricted to registered users only Available under License Publisher holds Copyright. Download (1MB)

BACKGROUND

Ga68 labelled somatostatin receptor ligand PET imaging has recently been shown in preclinical and early human studies to have a potential role in the evaluation of vulnerable arterial plaques. We prospectively evaluated carotid plaque Ga68-DOTATATE uptake in patients with recent carotid events, assessed inter- and intra- observer variability of such measurements, and explored the mechanism of any plaque DOTATATE activity with immunohistochemistry in resected specimens.

MATERIALS & METHODS

20 consecutively consenting patients with recent symptomatic carotid events (transient ischaemic attack [TIA], stroke or amaurosis fugax), due for carotid endarterectomy were prospectively recruited. Ga68-DOTATATE PET/CT of the neck was performed prior to surgery. Ga68-DOTATATE uptake was measured by drawing regions of interest (ROI) along the carotid plaques and contralateral plaques/carotid arteries by experienced radionuclide radiologist and radiographer. Two PET quantification methods with inter- and Intra-observer variability were assessed. Resected carotid plaques were retrieved for sst-2 immunohistochemical stain.

RESULTS

Median time delay between research PET and surgery was 2days. SUV and TBR values for the symptomatic plaques and the asymptomatic contralateral carotid arteries/plaques show no significant difference (n = 19, p-value >0.10), regardless of quantification method. Intraclass correlation coefficient was >0.8 in all measures of carotid artery/plaque uptake (SUV) and >0.6 in almost all measures of target-to-background ratio (TBR). None of the excised plaques were shown to contain cells (macrophages, lymphocytes, vessel-associated cells) expressing sst2 on their cell membrane.

CONCLUSION

Ga68 DOTATATE activity on PET in recently symptomatic carotid plaques is not significantly different to contralateral carotids/plaques. Any activity seen on PET is not shown to be from specific sst2 receptor-mediated uptake in-vitro. It is therefore unlikely that sst2 PET/CT imaging will have a role in the detection and characterization of symptomatic carotid plaques.

Interest & Impact

Downloads

2 since deposited on 18 Jan 2017
0 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item