Dataset Information

Application of speCtraL computed tomogrAphy to impRove specIficity of cardiac compuTed tomographY (CLARITY study): rationale and design.

ABSTRACT: INTRODUCTION:Anatomic stenosis evaluation on coronary CT angiography (CCTA) lacks specificity in indicating the functional significance of a stenosis. Recent developments in CT techniques (including dual-layer spectral detector CT [SDCT] and static stress CT perfusion [CTP]) and image analyses (including fractional flow reserve [FFR] derived from CCTA images [FFRCT] and deep learning analysis [DL]) are potential strategies to increase the specificity of CCTA by combining both anatomical and functional information in one investigation. The aim of the current study is to assess the diagnostic performance of (combinations of) SDCT, CTP, FFRCT and DL for the identification of functionally significant coronary artery stenosis. METHODS AND ANALYSIS:Seventy-five patients aged 18 years and older with stable angina and known coronary artery disease and scheduled to undergo clinically indicated invasive FFR will be enrolled. All subjects will undergo the following SDCT scans: coronary calcium scoring, static stress CTP, rest CCTA and if indicated (history of myocardial infarction) a delayed enhancement acquisition. Invasive FFR of ?0.80, measured within 30 days after the SDCT scans, will be used as reference to indicate a functionally significant stenosis. The primary study endpoint is the diagnostic performance of SDCT (including CTP) for the identification of functionally significant coronary artery stenosis. Secondary study endpoint is the diagnostic performance of SDCT, CTP, FFRCT and DL separately and combined for the identification of functionally significant coronary artery stenosis. ETHICS AND DISSEMINATION:Ethical approval was obtained. All subjects will provide written informed consent. Study findings will be disseminated through peer-reviewed conference presentations and journal publications. TRIAL REGISTRATION NUMBER:NCT03139006; Pre-results.

SUBMITTER: van Hamersvelt RW

PROVIDER: S-EPMC6429912 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Application of speCtraL computed tomogrAphy to impRove specIficity of cardiac compuTed tomographY (CLARITY study): rationale and design.

van Hamersvelt Robbert Willem RW Išgum Ivana I de Jong Pim A PA Cramer Maarten Jan Maria MJM Leenders Geert E H GEH Willemink Martin J MJ Voskuil Michiel M Leiner Tim T

BMJ open 20190301 3

<h4>Introduction</h4>Anatomic stenosis evaluation on coronary CT angiography (CCTA) lacks specificity in indicating the functional significance of a stenosis. Recent developments in CT techniques (including dual-layer spectral detector CT [SDCT] and static stress CT perfusion [CTP]) and image analyses (including fractional flow reserve [FFR] derived from CCTA images [FFR<sub>CT</sub>] and deep learning analysis [DL]) are potential strategies to increase the specificity of CCTA by combining both ...[more]

PMID: 30826767

Similar Datasets

Project description:RationaleAbout one-third of ischaemic strokes are caused by cardioembolism, and a substantial proportion of cryptogenic strokes likely also originate from the heart or aortic arch. Early determination of aetiology is important to optimise management. Computed Tomography-angiography of the heart is emerging as an alternative to echocardiography to detect cardio-aortic sources of embolism in stroke patients, but its diagnostic yield in acute ischaemic stroke has not been thoroughly assessed.Hypothesis: We hypothesise that electrocardiography-gated computed tomography-angiography of the heart and aortic arch, acquired in the acute phase in patients with ischaemic stroke, has a higher diagnostic yield than transthoracic echocardiography as a first-line screening method for detection of cardio-aortic sources of embolism.Methods and designMind the Heart is a single-centre prospective observational cohort study. We will include consecutive adult patients with acute ischaemic stroke who are potentially eligible for reperfusion therapy. Patients undergo non-electrocardiography-gated computed tomography-angiography of the aortic arch, cervical and intracranial arteries, directly followed by prospective sequential electrocardiography-gated cardiac computed tomography-angiography. Routine work-up for cardioembolism including 12-leads electrocardiography, Holter electrocardiography and transthoracic echocardiography is performed as soon as possible. The primary endpoint is the proportion of patients with a predefined high-risk cardio-aortic source of embolism on computed tomography-angiography versus transthoracic echocardiography in patients who underwent both investigations. Based on an expected 5% additional yield of computed tomography-angiography, a sample size of 450 patients is required.ConclusionsThe Mind the Heart study will generate a reliable estimate of the diagnostic yield of echocardiography-gated cardio-aortic computed tomography-angiography performed in the acute phase of ischaemic stroke.

Project description:BackgroundIt is difficult to distinguish the pathological grade of lung adenocarcinoma (LUAD) with traditional computed tomography (CT). The aim of this study was to assess tumor differentiation by dual-layer spectral detector CT combined with morphological parameters.MethodsIn this prospective study, a total of 67 patients with pathologically diagnosed LUAD were enrolled: 39 patients in the well- and moderately-differentiated group (14 and 25 patients, respectively) and 28 patients in the poorly-differentiated group. Morphological parameters, non-enhanced CT number, double-enhanced CT number, effective atomic number, monoenergetic CT images (40 and 70 keV), iodine density, and thoracic aorta iodine density of tumors were measured. The slope of the spectral curve and normalized iodine density were calculated. The diagnostic efficiency of the spectral parameters alone, and the combined spectral and morphological parameters were obtained by statistical analysis.ResultsThe morphological signs of LUAD (the vessel convergence sign, bronchus encapsulated air sign, and liquefactive necrosis) were higher in the poorly-differentiated group than in the well-moderately-differentiated group (57.1% vs. 30.8%, 40.0%; 60.7% vs. 28.2%, 32.0%; 64.3% vs. 28.2%, 24.0%; all P<0.05). There were significant differences in normalized iodine density (arterial phase: 0.10±0.04 vs. 0.12±0.05, 0.13±0.04; venous phase: 0.31±0.07 vs. 0.39±0.17, 0.40±0.17) among the poorly-differentiated group and moderately-differentiated group as well as the well-differentiated group (all P<0.05). Receiver operating characteristic (ROC) curves of the poorly-differentiated group and well-moderately-differentiated group showed that the normalized iodine density had the best diagnostic efficiency in the arterial phase, with an area under the curve (AUC) of 0.817, sensitivity of 92.9%, and specificity of 82.1% (P<0.001). The AUC increased to 0.916 when the morphological parameters were included, and sensitivity and specificity were 96.4% and 82.1% (P<0.001), respectively.ConclusionsThe parameters of dual-layer spectral detector CT can help discriminate the pathological grade of LUAD. Among the spectral parameters, the normalized iodine density in the arterial phase has the best diagnostic efficiency, and the combination of spectral and morphological parameters improves the pathological grading of LUAD.

Project description:BackgroundTo explore the feasibility and effectiveness of the metal artifact reduction software (MARs) reconstruction algorithm in reducing metal artifacts of knee prostheses and to explore the optimal monochromatic level of virtual monochromatic spectral (VMS) images for artifact reduction to provide high-quality images and reliable diagnosis in patients after total knee arthroplasty (TKA).MethodsA total of 31 patients underwent gemstone spectral computed tomography. VMS images with MARs and without MARs were obtained at different energy levels (80, 100, 120, and 140 keV). Two observers scored each group of images, and interobserver agreement was evaluated. Artificial indices (AIs), percentage500HU and structural similarity index measure (SSIM) values were calculated in the objective analysis to evaluate the image quality and impact of metal artifacts.ResultsThe consistency of the scores of the 2 observers was good (kappa value =0.78), and the score of the VMS images with MARs was higher than that of VMS images without MARs. AI values and percentage500HU of the MARs group were significantly lower than those of the without MARs group, while SSIM values were significantly higher. In the comparison of different keV images, the AI value decreased with the increase in keV in the range of 80-120 keV, but there was no significant difference between the 120 keV images and 140 keV images. In the group with MARs, the percentage500HU of 100-140 keV images was significantly lower than that of the 80 keV images, but there was no significant difference between 100, 120, and 140 keV images. In the group without MARs, the percentage500HU was significantly different among all keV groups.ConclusionsVMS images combined with the MARs algorithm can significantly reduce the metal artifacts of knee prostheses and improve image quality. At an energy level of 100-120 keV, a good metal artifact removal effect and soft tissue contrast can be achieved, and the best metal artifact removal effect can be achieved at 140 keV.

Project description:BackgroundComputed tomography angiography (CTA) is the recommended diagnostic and follow-up imaging modality for acute aortic dissection (AD). However, the high-contrast medium burden associated with repeated CT aortography follow-ups remains a significant concern. This prospective study aimed to assess whether an ultra-low contrast dose (75% cutoff) aortic CTA protocol on dual-layer spectral CT could achieve comparable image quality with the full dose protocol. We also investigated the image quality of the virtual noncontrast (VNC) images derived from the ultra-low dose protocol.MethodsThis study included 37 consecutive patients who were referred to aortic CTA from May 2022 to August 2022. The enrolled patients underwent full-dose contrast CTA and ultra-low dose (reduced to 25% of conventional) contrast CTA on dual-layer spectral CT in 1 day. Virtual monochromatic images (VMIs) were reconstructed with 40 and 70 keV. The VNC images were reconstructed for both protocols. Objective image quality evaluation, recorded as signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs), was compared between the groups using 1-way analysis of variance and post hoc analysis with Bonferroni correction. Subjective image quality was also compared between the groups. Finally, VNC images derived from the low-dose (VNClow) and full-dose (VNCfull) protocols were compared to the true noncontrast (TNC) images.ResultsNeither CNR nor SNR was lower for the 40-keV images reconstructed from the ultra-low dose group compared to the conventional images. Both were significantly higher than those of the 70-keV images. Regarding subjective image quality, vessel enhancement was not significantly different between the 40-keV VMI and full-dose images [ascending aorta (AAO): 4.37±0.46 vs. 4.57±0.48, P=0.096; brachiocephalic arteries: 4.34±0.45 vs. 4.51±0.49, P=0.152; abdominal aortic side branch: 4.42±0.48 vs. 4.51±0.49, P=0.480]. The VNClow images were similar to the TNC images but significantly different from the VNCfull images (P<0.001).ConclusionsUltra-low contrast aortic CTA with a 75%-reduced iodine dose using dual-layer spectral CT and the derived VNC achieved image quality comparable to that of conventional CTA and TNC images.

Project description:BackgroundComputed tomography is the most frequently used imaging modality in acute stroke imaging protocols. Detection of small volume infarcts in the brain and cardioembolic sources of stroke is difficult with current computed tomography protocols. Furthermore, the role of computed tomography findings to predict recurrent ischemic stroke is unclear. With ENCLOSE, we aim to improve (1) the detection of small volume infarcts with thin slice computed tomography perfusion (CTP) images and thromboembolic source with cardiac computed tomography techniques in the acute stage of ischemic stroke and (2) prediction of recurrent ischemic stroke with computed tomography-derived predictors.Methods/design: ENCLOSE is a prospective multicenter observational cohort study, which will be conducted in three Dutch stroke centers (ClinicalTrials.gov Identifier: NCT04019483). Patients (≥18 years) with suspected acute ischemic stroke who undergo computed tomography imaging within 9 h after symptom onset are eligible. Computed tomography imaging includes non-contrast CT, CTP, and computed tomography angiography (CTA) from base of the heart to the top of the brain. Dual-energy CT data will be acquired when possible, and thin-slice CTP reconstructions will be obtained in addition to standard 5 mm CTP data. CTP data will be processed with commercially available software and locally developed model-based methods. The post-processed thin-slice CTP images will be compared to the standard CTP images and to magnetic resonance diffusion-weighted imaging performed within 48 h after admission. Detection of cardioembolic sources of stroke will be evaluated on the CTA images. Recurrence will be evaluated 90 days and two years after the index event. The added value of imaging findings to prognostic models for recurrent ischemic stroke will be evaluated.ConclusionThe aim of ENCLOSE is to improve early detection of small volume stroke and thromboembolic sources and to improve prediction of recurrence in patients with acute ischemic stroke.

Dataset Information

Application of speCtraL computed tomogrAphy to impRove specIficity of cardiac compuTed tomographY (CLARITY study): rationale and design.

Publications

Application of speCtraL computed tomogrAphy to impRove specIficity of cardiac compuTed tomographY (CLARITY study): rationale and design.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets