Potential of Integrated [<sup>18</sup>F] Fluorodeoxyglucose Positron-Emission Tomography/CT in Identifying Vulnerable Carotid Plaques

Kwee, Robert M.; Truijman, Martine T. B.; Mess, W.H.; Teule, G. J. J.; Berg, Johannes W.M. ter; Franke, Cees L.; Korten, Arthur G. G. C.; Meems, Bé J.; Prins, Martin H.; Engelshoven, Jos M. A. van; Wildberger, Joachim E.; Oostenbrugge, Robert J. van; Kooi, M. Eline

doi:10.3174/ajnr.a2381

Cited by 44 publications

(40 citation statements)

References 19 publications

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“…Our correlation coefficient for blood background of 0.75 inevitably increases the inter-observer variability of all background-corrected values. Other 18 F-FDG uptake reproducibility studies in localized carotid artery plaques have reported moderate (background corrected) 28 to excellent (with and without background correction) 22,29 inter-observer agreement. The slightly inferior inter-observer agreement for background-corrected values found in our study could be related to differences in the placement of the ROI in the jugular vein as the diameter of the jugular vein often was small, making the measurement susceptible to image noise.…”

Section: Discussionmentioning

confidence: 99%

18F-FDG PET/CT for the quantification of inflammation in large carotid artery plaques

Johnsrud

Skagen

Seierstad

et al. 2019

Journal of Nuclear Cardiology

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Background. There is currently no consensus on the methodology for quantification of 18 F-FDG uptake in inflammation in atherosclerosis. In this study, we explore different methods for quantification of 18 F-FDG uptake in carotid atherosclerotic plaques and correlate the uptake values to histological assessments of inflammation.Methods and Results. Forty-four patients with atherosclerotic stenosis ‡70% of the internal carotid artery underwent 18 F-FDG PET/CT. Maximum standardized uptake values (SUV max ) from all plaque-containing slices were collected. SUV max for the single highest and the mean of multiple slices with and without blood background correction (by subtraction (cSUV) or by division (target-to-background ratio (TBR)) were calculated. Following endarterectomy 30 plaques were assessed histologically. The length of the plaques at CT was 6-32 mm. The 18 F-FDG uptake in the plaques was 1.15-2.66 for uncorrected SUVs, 1.16-3.19 for TBRs, and 0.20-1.79 for cSUVs. There were significant correlations between the different uptake values (r 5 0.57-0.99, P < 0.001). Methods with and without blood background correction showed similar, moderate correlations to the amount of inflammation assessed at histology (r 5 0.44-0.59, P < 0.02).Conclusions. In large stenotic carotid plaques, 18 F-FDG uptake reflects the inflammatory status as assessed at histology. Increasing number of PET slices or background correction did not change the correlation. (J Nucl Cardiol 2017)

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Section: Discussionmentioning

confidence: 99%

18F-FDG PET/CT for the quantification of inflammation in large carotid artery plaques

Johnsrud

Skagen

Seierstad

et al. 2019

Journal of Nuclear Cardiology

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“…53,58,66 FDG imaging of carotid plaques shows the most promise when used as an adjunct to other imaging modalities, especially MRI. A number of investigators have examined the value of the combination of FDG-PET to detect active inflammation and MRI to identify worrisome morphological features for the optimization of risk stratification.…”

mentioning

confidence: 99%

Contemporary carotid imaging: from degree of stenosis to plaque vulnerability

Brinjikji¹,

Huston²,

Rabinstein

et al. 2016

JNS

290

172

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abbreviatioNs AHA = American Heart Association; CAS = carotid artery stenting; CEA = carotid endarterectomy; CEUS = contrast-enhanced ultrasonography; CTA = CT angiography; DCE = dynamic contrast-enhanced; DSCT = dual-source CT; FDG = fluorodeoxyglucose; FSE = fast spin echo; Gd = gadolinium; HU = Hounsfield units; IPH = intraplaque hemorrhage; LRNC = lipid-rich necrotic core; MDCT = multidetector-row CT; MDCTA = MDCT angiography; MES = microembolic signal; MMP-9 = matrix metalloproteinase-9; MRA = MR angiography; PDW = proton density-weighted; SUV = standardized uptake value; SUVmax = maximal SUV; TBR = target-to-background ratio; TCD = transcranial Doppler ultrasonography; TIA = transient ischemic attack; TOF = time of flight; USPIO = ultrasmall superparamagnetic iron oxide. Carotid artery stenosis is a well-established risk factor of ischemic stroke, contributing to up to 10%-20% of strokes or transient ischemic attacks. Many clinical trials over the last 20 years have used measurements of carotid artery stenosis as a means to risk stratify patients. However, with improvements in vascular imaging techniques such as CT angiography and MR angiography, ultrasonography, and PET/CT, it is now possible to risk stratify patients, not just on the degree of carotid artery stenosis but also on how vulnerable the plaque is to rupture, resulting in ischemic stroke. These imaging techniques are ushering in an emerging paradigm shift that allows for risk stratifications based on the presence of imaging features such as intraplaque hemorrhage (IPH), plaque ulceration, plaque neovascularity, fibrous cap thickness, and presence of a lipid-rich necrotic core (LRNC). It is important for the neurosurgeon to be aware of these new imaging techniques that allow for improved patient risk stratification and outcomes. For example, a patient with a low-grade stenosis but an ulcerated plaque may benefit more from a revascularization procedure than a patient with a stable 70% asymptomatic stenosis with a thick fibrous cap. This review summarizes the current state-of-the-art advances in carotid plaque imaging. Currently, MRI is the gold standard in carotid plaque imaging, with its high resolution and high sensitivity for identifying IPH, ulceration, LRNC, and inflammation. However, MRI is limited due to time constraints. CT also allows for high-resolution imaging and can accurately detect ulceration and calcification, but cannot reliably differentiate LRNC from IPH. PET/CT is an effective technique to identify active inflammation within the plaque, but it does not allow for assessment of anatomy, ulceration, IPH, or LRNC. Ultrasonography, with the aid of contrast enhancement, is a cost-effective technique to assess plaque morphology and characteristics, but it is limited in sensitivity and specificity for detecting LRNC, plaque hemorrhage, and ulceration compared with MRI. Also summarized is how these advanced imaging techniques are being used in clinical practice to risk stratify patients with low- and high-grade carotid artery stenosis....

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“…34 Additionally, high FdG uptake is supposed to be detectable for around 1 month after symptoms, which is much longer than presence of MES. 30,35 Inflammation was predominant in the soft component of the plaque compared with the calcified one, emphasizing thereby the importance of measuring separately uptake within this part of the plaque. This finding was in agreement with an earlier study published by Rudd, which showed among 41 patients that calcification and inflammation rarely overlapped within arteries.…”

Section: Discussionmentioning

confidence: 99%

18fdg-Pet-Ct

Muller

Viaccoz

Fisch

et al. 2014

Stroke

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A lthough the degree of lumen obstruction is a relevant marker of the risk of stroke, the recognition of the role of the vulnerable plaque has opened new insights in the field of atherothrombotic stroke. [1][2][3][4] Vulnerability is dictated in part by plaque morphology, which, in turn, is influenced by pathophysiologic mechanisms at the cellular and molecular level. Thus, a certain number of features of plaque morphology may play an important role in the occurrence of cerebrovascular events. [5][6][7] An unstable plaque, on the one hand, has a thin fibrous cap that contains large numbers of macrophages and T lymphocytes and a small number of smooth muscle cells. A stable plaque, on the other hand, has a thicker cap with larger numbers of smooth muscle cells and less inflammation. [8][9][10] Intensive research has been performed aimed at optimizing different imaging modalities to precisely analyze the arterial wall morphology, plaque composition, and degree of local inflammation. Among them, positron emission tomography (PET) using 18 fluoro-2-deoxy-d-glucose (18FdG) as a radiotracer has shown promise for detection of local inflammation in atherosclerotic plaques.11 Indeed, high levels of glucose metabolism are typically seen in tissue with inflammatory activity. 12 Moreover, significant positive correlations between histopathologic findings and degree of plaque inflammation depicted by 18FdG uptake have been documented. [13][14][15][16][17][18] Accordingly, a few clinical studies suggested a potential role of 18FdG-PET-computed tomography (CT) for the diagnosis of high-risk carotid plaques. Rudd et al 13 showed that PET-CT might be used to image inflammatory cell activity within the carotid plaque. The study involved only 8 patients but was capable to demonstrate that 18FdG uptake was significantly higher within the symptomatic as compared with the contralateral plaque. Another study showed in a retrospective analysis Background and Purpose-We investigated whether uptake of 18 fluoro-2-deoxy-d-glucose (18FdG) positron emission tomography-computed tomography (PET-CT) correlated to clinical symptoms and presence of microembolic signals (MES) detected by transcranial doppler in patients with carotid stenosis. Methods-18FdG-PET-CT and MES detection was performed in consecutive patients with 50% to 99% symptomatic or asymptomatic carotid stenoses. Uptake index was defined by a target to background ratio (TBR) between maximum standardized uptake value of the carotid plaque and the mean standardized uptake value of the jugular veins. End points for analysis were presence of symptoms and presence of MES. 22,23 A recent study showed a correlation between 18FdG-PET-MRI and presence of MES in 16 patients presenting with recent transient ischemic attack or minor stroke and 50% to 99% stenosis of the ipsilateral carotid bifurcation. There was a significant difference in the target to background ratio (TBR) values between MES positive (+) and MES negative (−) patients, reinforcing the notion that embolization occurring dist...

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Potential of Integrated [¹⁸F] Fluorodeoxyglucose Positron-Emission Tomography/CT in Identifying Vulnerable Carotid Plaques

Abstract: BACKGROUND AND PURPOSE:There is a need for improved risk stratification of patients with TIA/ stroke and carotid atherosclerosis. The purpose of this study was to prospectively investigate the potential of integrated 18 F-FDG PET/MDCT in identifying vulnerable carotid plaques.

Cited by 44 publications

References 19 publications

18F-FDG PET/CT for the quantification of inflammation in large carotid artery plaques

18F-FDG PET/CT for the quantification of inflammation in large carotid artery plaques

Contemporary carotid imaging: from degree of stenosis to plaque vulnerability

18fdg-Pet-Ct

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Potential of Integrated [18F] Fluorodeoxyglucose Positron-Emission Tomography/CT in Identifying Vulnerable Carotid Plaques

Abstract: BACKGROUND AND PURPOSE:There is a need for improved risk stratification of patients with TIA/ stroke and carotid atherosclerosis. The purpose of this study was to prospectively investigate the potential of integrated 18 F-FDG PET/MDCT in identifying vulnerable carotid plaques.

Cited by 44 publications

References 19 publications

18F-FDG PET/CT for the quantification of inflammation in large carotid artery plaques

18F-FDG PET/CT for the quantification of inflammation in large carotid artery plaques

Contemporary carotid imaging: from degree of stenosis to plaque vulnerability

18fdg-Pet-Ct

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Potential of Integrated [¹⁸F] Fluorodeoxyglucose Positron-Emission Tomography/CT in Identifying Vulnerable Carotid Plaques