Motion Correction of ¹⁸F-NaF PET for Imaging Coronary Atherosclerotic Plaques

Abstract

Ruptured coronary atherosclerotic plaques commonly cause acute myocardial infarction. It has recently been shown that active microcalcification in the coronary arteries, one of the features that characterizes vulnerable plaques at risk of rupture, can be imaged using 18 F-NaF PET. We aimed to determine whether a motion correction technique applied to gated 18 F-NaF PET images could enhance image quality and improve uptake estimates. Methods: Seventeen patients with myocardial infarction (n 5 7) or stable angina (n 5 10) underwent 18 F-NaF PET and prospective coronary CT angiography. PET data were reconstructed in 4 different ways: the first was 1 gated bin (end-diastolic phase with 25% of the counts), the second was 4 gated bins (consecutive 25% segments), the third was 10 gated bins (consecutive 10% segments), and the fourth was ungated. Subsequently, with data from either 4 or 10 bins, gated PET images were registered using a local, nonlinear motion correction method guided by the extracted coronary arteries from CT angiography. Global noise levels and target-to-background ratios (TBR) defined on manually delineated coronary plaque lesions were compared to assess image quality and uptake estimates. Results: Compared with the reference standard of using only 1 bin of PET data, motion correction using 10 bins of PET data reduced image noise by 46% (P , 0.0001). TBR in positive lesions for 10-bin motion-corrected data was 11% higher than for 1-bin data (1.98 [interquartile range, 1.70-2.37] vs. 1.78 [1.58-2.16], P 5 0.0027) and 33% higher than for ungated data (1.98 [1.70-2.37] vs. 1.49 [1.39-1.88], P , 0.0001). Conclusion: Motion correction of gated 18 F-NaF PET/coronary CT angiography is feasible, reduces image noise, and increases TBR. This improvement may allow more reliable identification of vulnerable coronary artery plaques using 18 F-NaF PET.

Cardiac αVβ3integrin expression following acute myocardial infarction in humans

“…PET/CT scanning with 18 F-fluciclatide and CMR were performed in three groups of participants recruited from Royal Infirmary of Edinburgh between July 2013 and February 2015. Exclusion criteria were age <40 years, women of childbearing potential not taking contraception, severe renal failure (serum creatinine >2.8 mg/dL) or hepatic failure (Child-Pugh grade B or grade C), atrial fibrillation, contrast allergy, inability to undergo scanning and inability to provide informed consent.…”

“…In this study, we investigated the expression of α v β 3 integrin following MI using the novel α v β 3 integrin-selective radiotracer, 18 F-fluciclatide, combined with cardiac positron emission tomography (PET), CT and cardiovascular MRI (CMR). The study aims to describe and characterise the uptake of this radiotracer and to correlate it with clinical markers of disease severity and functional recovery in patients with recent MI.…”

Motion-Corrected Imaging of the Aortic Valve with 18F-NaF PET/CT and PET/MRI: A Feasibility Study

“…Cardiac motion correction was performed using an anatomically-guided automated registration algorithm, similar to our method described previously (7,12). First, a three-dimensional sphere was drawn to define the aortic valve region.…”

Imaging of atherosclerosis

“…Alternatively, postprocessing methods for PET image motion correction include data-driven correction respiratory gating using deformation fields generated from 4D PET, 207 and cardiac motion frozen technique. 208 Motion correction of gated 18 F-NaF coronary PET images is feasible and has been shown to reduce noise and increase tissue-to-background ratio compared with ungated and single-bin data (Figure 8). 208 Such advances will, in future, help to facilitate translation of atherosclerosis imaging techniques on the horizon to routine clinical practice.…”

“…208 Motion correction of gated 18 F-NaF coronary PET images is feasible and has been shown to reduce noise and increase tissue-to-background ratio compared with ungated and single-bin data (Figure 8). 208 Such advances will, in future, help to facilitate translation of atherosclerosis imaging techniques on the horizon to routine clinical practice.…”