scholarly journals Flow Dynamics in the Aortic Arch and Its Effect on the Arterial Input Function in Cardiac Computed Tomography

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Parastou Eslami ◽  
Jung-Hee Seo ◽  
Albert C. Lardo ◽  
Marcus Y. Chen ◽  
Rajat Mittal
Keyword(s):  
Computed Tomography ◽  
Aortic Arch ◽  
Rise Time ◽  
Arterial Input Function ◽  
Cardiac Computed Tomography ◽  
Time Lag ◽  
Input Function ◽  
Patient Specific ◽  
Descending Aorta ◽  
Coronary Ostia

The arterial input function (AIF)—time-density curve (TDC) of contrast at the coronary ostia—plays a central role in contrast enhanced computed tomography angiography (CTA). This study employs computational modeling in a patient-specific aorta to investigate mixing and dispersion of contrast in the aortic arch (AA) and to compare the TDCs in the coronary ostium and the descending aorta. Here, we examine the validity of the use of TDC in the descending aorta as a surrogate for the AIF. Computational fluid dynamics (CFD) was used to study hemodynamics and contrast dispersion in a CTA-based patient model of the aorta. Variations in TDC between the aortic root, through the AA and at the descending aorta and the effect of flow patterns on contrast dispersion was studied via postprocessing of the results. Simulations showed complex unsteady patterns of contrast mixing and dispersion in the AA that are driven by the pulsatile flow. However, despite the relatively long intra-aortic distance between the coronary ostia and the descending aorta, the TDCs at these two locations were similar in terms of rise-time and up-slope, and the time lag between the two TDCs was 0.19 s. TDC in the descending aorta is an accurate analog of the AIF. Methods that use quantitative metrics such as rise-time and slope of the AIF to estimate coronary flowrate and myocardial ischemia can continue with the current practice of using the TDC at the descending aorta as a surrogate for the AIF.

scholarly journals The Role of Computed Tomography in the Diagnosis of Rare Congenital Heart Disease: Interrupted Aortic Arch

2021 ◽  
Author(s):  
Yusen Feng ◽  
Lijuan Wang ◽  
Hui Liu ◽  
Guifang Sun ◽  
Bin Liu ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Pulmonary Artery ◽  
Aortic Arch ◽  
Type A ◽  
Left Pulmonary Artery ◽  
Imaging Features ◽  
Type B ◽  
Descending Aorta ◽  
Trunk Diameter ◽  
Right Pulmonary Artery

Abstract Background: Interrupted aortic arch (IAA) is a rare congenital anomaly of the aortic arch and an anatomical interruption of the lumen between the ascending and descending aorta. Computed tomography (CT) has become a reliable noninvasive diagnostic method for congenital IAA .The purpose of this study was to To investigate the imaging features of IAA and improve the understanding and diagnosis of the disease. Methods: The imaging features and postoperative pathological data of 25 patients with IAA confirmed by dual-source computed tomography (DSCT) angiography were analyzed in this retrospective study. Results: Among the 25 patients with IAA, 15 were type A, 7 were type B, 0 were type C and D, and 2 were type E. The diameter of the pulmonary artery trunk in type A was larger than that in type B (P < 0.05). However, there were no significantly different between type A and type B abomg the ascending aorta diameter; descending aorta; ascending aorta/ descending aorta ratio; left pulmonary artery main trunk diameter; right pulmonary artery main trunk diameter; left pulmonary artery trunk/ pulmonary artery trunk ratio; right pulmonary artery trunk/pulmonary artery trunk ratio; left pulmonary artery trunk/right pulmonary artery trunk ratio.Conclusion: The imaging findings of IAA have typical and specific signs, and the types of IAA are not comprehensive. One type of patient identification can be added: patients who are dissected between the left common carotid artery and left subclavian artery opening, and the descending aorta is circulated by the chest collaterals. Patients with wide pulmonary artery in the IAA are usually type A patients. Patients with IAA after surgical repair require lifetime follow-up, mainly to monitor left ventricular outflow tract obstruction and recurrent aortic coarctation.

scholarly journals Quantifying lumbar vertebral perfusion by a Tofts model on DCE-MRI using segmental versus aortic arterial input function

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yi-Jui Liu ◽  
Hou-Ting Yang ◽  
Melissa Min-Szu Yao ◽  
Shao-Chieh Lin ◽  
Der-Yang Cho ◽  
...  
Keyword(s):  
Arterial Input Function ◽  
Lumbar Vertebrae ◽  
Region Of Interest ◽  
Input Function ◽  
Population Based ◽  
Patient Specific ◽  
Rank Test ◽  
Pharmacokinetic Parameters ◽  
Dce Mri ◽  
Signed Rank Test

AbstractThe purpose of this study was to investigate the influence of arterial input function (AIF) selection on the quantification of vertebral perfusion using axial dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). In this study, axial DCE-MRI was performed on 2 vertebrae in each of eight healthy volunteers (mean age, 36.9 years; 5 men) using a 1.5-T scanner. The pharmacokinetic parameters Ktrans, ve, and vp, derived using a Tofts model on axial DCE-MRI of the lumbar vertebrae, were evaluated using various AIFs: the population-based aortic AIF (AIF_PA), a patient-specific aortic AIF (AIF_A) and a patient-specific segmental arterial AIF (AIF_SA). Additionally, peaks and delay times were changed to simulate the effects of various AIFs on the calculation of perfusion parameters. Nonparametric analyses including the Wilcoxon signed rank test and the Kruskal–Wallis test with a Dunn–Bonferroni post hoc analysis were performed. In simulation, Ktrans and ve increased as the peak in the AIF decreased, but vp increased when delay time in the AIF increased. In humans, the estimated Ktrans and ve were significantly smaller using AIF_A compared to AIF_SA no matter the computation style (pixel-wise or region-of-interest based). Both these perfusion parameters were significantly greater using AIF_SA compared to AIF_A.

scholarly journals Mind the Heart: Electrocardiography-gated cardiac computed tomography-angiography in acute ischaemic stroke—rationale and study design

2020 ◽  
Vol 5 (4) ◽  
pp. 441-448
Author(s):  
Valeria Guglielmi ◽  
Leon A Rinkel ◽  
Nina-Suzanne Groeneveld ◽  
Nick HJ Lobé ◽  
S Matthijs Boekholdt ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Ischaemic Stroke ◽  
Aortic Arch ◽  
Acute Phase ◽  
Acute Ischaemic Stroke ◽  
Computed Tomography Angiography ◽  
Transthoracic Echocardiography ◽  
Diagnostic Yield ◽  
Cardiac Computed Tomography ◽  
Cardiac Computed Tomography Angiography

Rationale About 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 design Mind 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. Conclusions The 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.

scholarly journals Variation in arterial input function in a large multicenter computed tomography perfusion study

2021 ◽  
Author(s):  
Daan Peerlings ◽  
◽  
Edwin Bennink ◽  
Jan W. Dankbaar ◽  
Birgitta K. Velthuis ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Contrast Medium ◽  
Multicenter Study ◽  
Arterial Input Function ◽  
Input Function ◽  
Computed Tomography Perfusion ◽  
Stroke Diagnosis ◽  
Contrast Medium Injection ◽  
Injection Protocol ◽  
The Impact

Abstract Objectives To report the variation in computed tomography perfusion (CTP) arterial input function (AIF) in a multicenter stroke study and to assess the impact this has on CTP results. Methods CTP datasets from 14 different centers were included from the DUtch acute STroke (DUST) study. The AIF was taken as a direct measure to characterize contrast bolus injection. Statistical analysis was applied to evaluate differences in amplitude, area under the curve (AUC), bolus arrival time (BAT), and time to peak (TTP). To assess the clinical relevance of differences in AIF, CTP acquisitions were simulated with a realistic anthropomorphic digital phantom. Perfusion parameters were extracted by CTP analysis using commercial software (IntelliSpace Portal (ISP), version 10.1) as well as an in-house method based on block-circulant singular value decomposition (bSVD). Results A total of 1422 CTP datasets were included, ranging from 6 to 322 included patients per center. The measured values of the parameters used to characterize the AIF differed significantly with approximate interquartile ranges of 200–750 HU for the amplitude, 2500–10,000 HU·s for the AUC, 0–17 s for the BAT, and 10–26 s for the TTP. Mean infarct volumes of the phantom were significantly different between centers for both methods of perfusion analysis. Conclusions Although guidelines for the acquisition protocol are often provided for centers participating in a multicenter study, contrast medium injection protocols still vary. The resulting volumetric differences in infarct core and penumbra may impact clinical decision making in stroke diagnosis. Key Points • The contrast medium injection protocol may be different between stroke centers participating in a harmonized multicenter study. • The contrast medium injection protocol influences the results of X-ray computed tomography perfusion imaging. • The contrast medium injection protocol can impact stroke diagnosis and patient selection for treatment.

scholarly journals Patient-Specific Method of Generating Parametric Maps of Patlak Ki without Blood Sampling or Metabolite Correction: A Feasibility Study

2011 ◽  
Vol 2011 ◽  
pp. 1-12 ◽  
Author(s):  
George A. Sayre ◽  
Benjamin L. Franc ◽  
Youngho Seo
Keyword(s):  
Arterial Input Function ◽  
Therapy Monitoring ◽  
Input Function ◽  
Blood Sampling ◽  
Radiotherapy Planning ◽  
Patient Specific ◽  
Specific Method ◽  
Visual Contrast ◽  
Parametric Maps

Currently, kinetic analyses using dynamic positron emission tomography (PET) experience very limited use despite their potential for improving quantitative accuracy in several clinical and research applications. For targeted volume applications, such as radiation treatment planning, treatment monitoring, and cerebral metabolic studies, the key to implementation of these methods is the determination of an arterial input function, which can include time-consuming analysis of blood samples for metabolite correction. Targeted kinetic applications would become practical for the clinic if blood sampling and metabolite correction could be avoided. To this end, we developed a novel method (Patlak-P) of generating parametric maps that is identical to Patlak Ki (within a global scalar multiple) but does not require the determination of the arterial input function or metabolite correction. In this initial study, we show that Patlak-P (a) mimics Patlak Ki images in terms of visual assessment and target-to-background (TB) ratios of regions of elevated uptake, (b) has higher visual contrast and (generally) better image quality than SUV, and (c) may have an important role in improving radiotherapy planning, therapy monitoring, and neurometabolism studies.

Utility of Pre- and Postoperative Computed Tomography Angiography for the Evaluation of a Complex Vascular Ring

2019 ◽  
Vol 10 (5) ◽  
pp. 654-656
Author(s):  
Philip B. Dydynski ◽  
John S. Austin ◽  
Deborah Kozik ◽  
Bahaaldin Alsoufi
Keyword(s):  
Computed Tomography ◽  
Pulmonary Artery ◽  
Aortic Arch ◽  
Computed Tomography Angiography ◽  
Vascular Ring ◽  
Left Pulmonary Artery ◽  
Aberrant Right Subclavian Artery ◽  
Descending Aorta ◽  
Right Pulmonary Artery ◽  
The Right

We present the case of a neonate born with an unusual complex vascular ring formed by a left-sided aortic arch that had retroesophageal course to join a right-sided descending aorta and a very large right-sided arterial ductus from the right pulmonary artery to the descending aorta. Associated finings included aortic arch hypoplasia, aberrant right subclavian artery, and aberrant origin of the left pulmonary artery from the aorta. We focus on the role of computed tomography angiography in the preoperative and postoperative assessment of this complex anomaly.

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