Dual-layer spectral detector CT monoenergetic reconstruction improves image quality of non-contrast cerebral CT as compared with conventional single energy CT

Zhao, Xuemei; Wang, Man; Wu, Runze; Dharaiya, Ekta; Feng, Feng; Li, Ming-Li; You, Hui; Wang, Yun; Jin, Zhengyu

doi:10.1016/j.ejrad.2018.04.015

Cited by 21 publications

(26 citation statements)

References 24 publications

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“…Leveraging different monoenergetic reconstructions may help accentuate differences in energy-dependent attenuation differences between similar materials, e.g., normal brain tissue and ischemic/ edematous brain tissue. DECT VMI have demonstrated improved contrast-to-noise profiles and reduced beam-hardening artifact relative to NCT [10][11][12][13][14][15]. The potential of DECT for the visualization of brain edema has been investigated in earlier studies [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Virtual monochromatic dual-energy CT reconstructions improve detection of cerebral infarct in patients with suspicion of stroke

et al. 2020

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Purpose Early infarcts are hard to diagnose on non-contrast head CT. Dual-energy CT (DECT) may potentially increase infarct differentiation. The optimal DECT settings for differentiation were identified and evaluated. Methods One hundred and twenty-five consecutive patients who presented with suspected acute ischemic stroke (AIS) and underwent non-contrast DECT and subsequent DWI were retrospectively identified. The DWI was used as reference standard. First, virtual monochromatic images (VMI) of 25 patients were reconstructed from 40 to 140 keV and scored by two readers for acute infarct. Sensitivity, specificity, positive, and negative predictive values for infarct detection were compared and a subset of VMI energies were selected. Next, for a separate larger cohort of 100 suspected AIS patients, conventional non-contrast CT (NCT) and selected VMI were scored by two readers for the presence and location of infarct. The same statistics for infarct detection were calculated. Infarct location match was compared per vascular territory. Subgroup analyses were dichotomized by time from last-seen-well to CT imaging. Results A total of 80-90 keV VMI were marginally more sensitive (36.3-37.3%) than NCT (32.4%; p > 0.680), with marginally higher specificity (92.2-94.4 vs 91.1%; p > 0.509) for infarct detection. Location match was superior for VMI compared with NCT (28.7-27.4 vs 19.5%; p < 0.010). Within 4.5 h from last-seen-well, 80 keV VMI more accurately detected infarct (58.0 vs 54.0%) and localized infarcts (27.1 vs 11.9%; p = 0.004) than NCT, whereas after 4.5 h, 90 keV VMI was more accurate (69.3 vs 66.3%). Conclusion Non-contrast 80-90 keV VMI best differentiates normal from infarcted brain parenchyma.

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Section: Introductionmentioning

confidence: 99%

Virtual monochromatic dual-energy CT reconstructions improve detection of cerebral infarct in patients with suspicion of stroke

et al. 2020

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“…In recent years, many strategies have been evaluated to improve the quality of CTP scans including adjustment of the amount of contrast agent [130], the acquisition interval [131] and the use of iterative reconstructions [132]. In cerebral non-contrast CT images the use of monoenergetic images from dual energy or spectral CT has shown improved gray-white matter separation and increased CNR compared to conventional singe energy CT [50], but also increased sensitivity for detection of infarct in non-contrast CT images [23,94]. However, to our knowledge there…”

Section: Discussionmentioning

confidence: 99%

“…We did not objectively measure the image quality of the acquired CT images. However, prior studies found that conventional CT images from the DLCT and SLCT are of comparable image quality [41,49,50]. In addition, these scans were used clinically; we therefore concluded that the acquired images are of sufficient image quality for routine diagnostic evaluation.…”

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confidence: 81%

“…Virtual monochromatic images [74][75][76][77] have the potential to increase the conspicuity of cerebral pathology on non-contrast head CT [23,24,43,50,78], by its ability to reduce streak artifacts and beam-hardening artifacts, or to improve contrast attenuation in comparison to conventional CT imaging. However, VMI techniques and reconstruction algorithms vary between manufacturers.…”

Section: Introductionmentioning

confidence: 99%

“…normal brain tissue and ischemic/edematous brain tissue. DECT VMI have demonstrated improved contrast-to-noise profiles and reduced beam hardening artifact relative to NCT [23,24,43,50,78,80]. The potential of DECT for the visualization of brain edema has been investigated in earlier studies [89][90][91].…”

Section: Introductionmentioning

confidence: 99%

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Dual-energy CT and CT perfusion for improved CT stroke imaging

Ommen¹

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Cardiovascular diseases (CVDs) are the leading causes of death in the world. An estimated 17.9 million people died from a CVD worldwide in 2016. The majority, 85% of deaths, is caused by either a heart attack or a stroke[1]. In the Netherlands, 38199 people died of a CVD in 2018, of which 9176 died of a stroke[2]. Not only does stroke significantly contribute to mortality, it is also a leading cause of disability[3]. Because of the aging population, the number of stroke patients is expected to increase[4]. Strokes can be divided into two groups: 1) ischemic strokes caused by an arterial occlusion, for example by a (temporary) clot, and 2) hemorrhagic strokes caused by a rupture of a vessel[5]. In this thesis we will be focusing on ischemic strokes. Currently, treatment options for ischemic strokes are intravenous administration of tissue plasminogen activator (tPA) for clot dissolution, intra-arterial thrombolysis, and endovascular mechanical clot removal[6]. Therapeutic interventions are most effective when initiated in the early stages after a stroke[7-9]. Guidelines state that intravenous thrombolysis should only be administered to patients within 4.5 hours, and endovascular treatment should only be initiated within 6 hours of ischemic stroke symptom onset[10]. Brain tissue damage may be irreversible, and the loss of brain tissue continues while the arterial occlusion persists. Therefore in stroke care the phrase "time is brain" is often used, meaning that the diagnosis and treatment of a stroke should be as fast as possible. This explains why the preferred imaging modality for acute stroke imaging usually is computed tomography (CT)[11]. CT is fast, relatively cheap and widely available. The acute stroke imaging protocol usually consists of noncontrast CT, CT perfusion and CT angiography scans. CT imaging in stroke Non-contrast CT In stroke imaging, the first acquisition is non-contrast CT (NCCT) of the entire brain. The primary goal of NCCT is to differentiate between ischemic and hemorrhagic strokes. Since blood has a higher attenuation than brain tissue, it appears hyperdense on a CT scan and can therefore be easily detected (Figure 1.1A). In addition to differentiating ischemic from hemorrhagic strokes, NCCT also provides some information on the extent of cerebral ischemia. On NCCT, subtle loss of gray-white matter differentiation and evidence of swelling can be first indications of ischemic stroke[12]. The ischemic area appears hypodense on NCCT (Figure 1.1B). Figure 1.3 | Examples of contrast enhancement curves: A) arterial input function (AIF) and venous output function (VOF), B) gray matter (GM) and white matter (WM). The dashed line shows the partial volume corrected AIF. Figure 1.5 | Illustration of three dual-energy CT techniques. A) Dual-source DECT utilizes two X-ray tubes and two detectors to generate low-and high-energy spectra, B) rapid kV switching utilizes one X-ray tube and detector and switches rapidly between a low and high tube voltage and C) detector-based spectral CT utilizes one X-ray...

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