Photon-counting cine-cardiac CT in the mouse

Abstract

12The maturation of photon-counting detector (PCD) technology promises to 13 enhance routine CT imaging applications with high-fidelity spectral information. In this 14 paper, we demonstrate the power of this synergy and our complementary reconstruction 15 techniques, performing 4D, cardiac PCD-CT data acquisition and reconstruction in a 16 mouse model of atherosclerosis, including calcified plaque. Specifically, in vivo cardiac 17 micro-CT scans were performed in four ApoE knockout mice, following their development 18 of calcified plaques. The scans were performed with a prototype PCD (DECTRIS, Ltd.) 19 with 4 energy thresholds. Projection sampling was performed with 10 ms temporal 20 resolution, allowing the reconstruction of 10 cardiac phases at each of 4 energies (40, 3D 21 volumes per mouse scan). Reconstruction was performed iteratively using the split 34 detected during slow moving phases of the cardiac cycle. Given these preliminary results, 35 we believe that PCD technology will enhance dynamic CT imaging applications with high-36 fidelity spectral and material information. 37 42 Philips (dual-layer). These DE scanners are associated with several routine imaging 43 applications, including plaque differentiation, myocardial perfusion, and kidney stone 44 characterization [5]. Preclinically, spectral CT has been utilized in several additional 3 45 applications, including differential imaging of vasculature and vascular permeability in 46 sarcoma [6] and lung [7] tumors, and with several preclinical contrast agents based on 100 gene [22], show a marked increase in total plasma cholesterol levels, and are prone to 101 develop atherosclerotic lesions [23]. At 8-12 weeks of age, the ApoE-/-mice were 102 exposed to 25 fractions of 2 Gy partial-heart irradiation, mimicking cardiac radiation 103 exposure of breast cancer patients treated with radiation therapy [24]. After irradiation, 104 the mice were kept on a regular diet for a year prior to imaging. Three days before 105 imaging, the mice were intravenously injected with gold nanoparticle contrast agent (15 106 nm AuroVist, www.nanoprobes.com) at a dose of 0.004 mL/g mouse, with gold 107 accumulation expected at the site of any myocardial injury [24]. Notably, with an 80 kVp 108 source spectrum, K-edge imaging of gold (edge at 80.7 keV) was not possible. Three 109 days later, immediately prior to imaging, the same mice were injected with a liposomal 110 iodinated contrast agent (described in [8]; 0.012 mL/g mouse) to measure cardiac 111 functional metrics. The free-breathing mice were scanned while under anesthesia 112 induced with 1-2% isoflurane delivered by nose cone. Both ECG and respiratory signals 6 113 were recorded during scanning (average heart rate: 448 ± 50 bpm; average respiratory 114 rate: 142 ± 19 breaths/min.). The ECG signal was used for retrospective projection 115 weighting during reconstruction. Respiratory gating was not performed. 116 Multi-channel image reconstruction 117Following from our past work on data-adaptive, iterative reconstruc...

Deep learning models for rapid denoising of 5D cardiac photon-counting micro-CT images

“…For this study, we acquired PCD scans on our dual-source micro-CT imaging system with an EID and a PCD (Dectris Santis 1604, 150 μm pixel size, 4 energy thresholds) [12]. We scanned in vivo mice of various apolipoprotein E genotypes that were injected with liposomal Iodine (Lip-I) at a dosage of 0.012 ml/g of body weight [13]. The x-ray source settings were: 80 kVp tube voltage, 4 mA tube current, 10 ms/exposure.…”