Magnetic resonance imaging as a tool to assess reliability in simulating hemodynamics in cerebral aneurysms

Magnetic resonance imaging as a tool to assess reliability in simulating hemodynamics in cerebral aneurysms

Magnetic resonance imaging as a tool to assess reliability in simulating hemodynamics in cerebral aneurysms with a dedicated computational fluid dynamics prototype: preliminary results
Christof Karmonik1, Y. Jonathan. Zhang1, Orlando Diaz2, Richard Klucznik2, Sasan Partovi3, Robert G. Grossman1, Gavin W. Britz1

Review of MRI-based measurements of pulse wave velocity

Review of MRI-based measurements of pulse wave velocity

Review of MRI-based measurements of pulse wave velocity: a biomarker of arterial stiffness
Andrew L. Wentland1,2, Thomas M. Grist1,2, Oliver Wieben1,2

4D flow imaging with MRI

4D flow imaging with MRI

4D flow imaging with MRI
Zoran Stankovic1, Bradley D. Allen1, Julio Garcia1, Kelly B. Jarvis1, Michael Markl1,2
1Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago, USA; 2Department Biomedical Engineering, McCormick School of Engineering, Northwestern University, Chicago, USA

Dynamic contrast-enhanced magnetic resonance imaging: fundamentals and application to the evaluation of the peripheral perfusion

Dynamic contrast-enhanced magnetic resonance imaging: fundamentals and application to the evaluation of the peripheral perfusion

Dynamic contrast-enhanced magnetic resonance imaging: fundamentals and application to the evaluation of the peripheral perfusion
Authors: Yaron Gordon, Sasan Partovi, Matthias Müller-Eschner, Erik Amarteifio, Tobias Bäuerle, Marc-André Weber, Hans-Ulrich Kauczor, Fabian Rengier

Usefulness of MRI in takotsubo cardiomyopathy: a review of the literature

Usefulness of MRI in takotsubo cardiomyopathy: a review of the literature

Usefulness of MRI in takotsubo cardiomyopathy: a review of the literature
Andres Alejandro Kohan1, Ezequiel Levy Yeyati1, Luciano De Stefano2, Laura Dragonetti1, Marcelo Pietrani1, Diego Perez de Arenaza2, Cesar Belziti2, Ricardo Daniel García-Mónaco1

Reflections on renal denervation.

Reflections on renal denervation.

J Am Coll Cardiol. 2014 Apr 15;63(14):1452-3. doi: 10.1016/j.jacc.2014.03.001.
Reflections on renal denervation.
Demaria AN.

Tools for cardiovascular magnetic resonance imaging

Tools for cardiovascular magnetic resonance imaging

Tools for cardiovascular magnetic resonance imaging
Ramkumar Krishnamurthy, Benjamin Cheong, Raja Muthupillai
Department of Diagnostic and Interventional Radiology, CHI St. Luke’s Health, Texas Medical Center, Houston, Texas 77030, USA
Correspondence to: Raja Muthupillai. Department of Diagnostic and Interventional Radiology, St. Luke’s Hospital, Texas Medical Center, 6720 Bertner Avenue, Houston, Texas 77030, USA. Email: rmuthupillai@stlukeshealth.org.

Cardiac CT Made Easy: An Introduction to Cardiovascular Multidetector Computed Tomography, Second Edition

Cardiac CT Made Easy: An Introduction to Cardiovascular Multidetector Computed Tomography, Second Edition

Features

 

    • Describes the principles of multidetector computed tomography (MDCT) for cardiovascular applications

 

    • Examines practical aspects of scan acquisition and interpretation

 

 

    • Reviews clinical indications and imaging protocols

 

 

    • Discusses clinical findings of common cardiovascular disease conditions

 

 

    • Compares MDCT with other imaging modalities such as conventional angiography, intravascular ultrasound, magnetic resonance imaging, and echocardiography

 

 

    • Contains a large number of selected images highlighting key findings

 

 

    • Includes online access to imaging video clips

 

 

Summary

 

Obtaining and interpreting images of the heart is critical to the successful management of any cardiac disorders. Several imaging modalities are used to help cardiologists correctly diagnose these disorders and initiate the most appropriate form of treatment.

 

Since the first publication of this book, the use of cardiovascular CT imaging has increased exponentially. Revised and updated, Cardiac CT Made Easy: An Introduction to Cardiovascular Multidetector Computed Tomography, Second Edition* captures these advances in CT scanner technology and clinical experience. For the first time, this new edition includes online access to imaging video clips.

 

Combining the expertise of leading cardiovascular imaging groups in North America, Europe, and Asia, this second edition continues to serve as a comprehensive introduction to the field. It focuses on the principles of multidetector computed tomography (MDCT) for cardiovascular applications, practical aspects of scan acquisition and interpretation, clinical indications and imaging protocols, and clinical findings of common cardiovascular disease conditions. The book is an essential resource for those new to the field and a trustworthy reference for those needing answers to specific questions or looking to update their knowledge.

 

*Now includes an identical eBook version from VitalSource with access to video material

Paradoxical low-flow, low-gradient aortic stenosis despite preserved left ventricular ejection fraction: new insights from weights of operatively excised aortic valves.

Paradoxical low-flow, low-gradient aortic stenosis despite preserved left ventricular ejection fraction: new insights from weights of operatively excised aortic valves.

We reported that patients with small aortic valve area (AVA) and low flow despite preserved left ventricular ejection fraction (LVEF), i.e. ‘paradoxical‘ low flow (PLF), have worse outcomes compared with patients with normal flow (NF), although they generally have a lower mean gradient (MG). The aortic valve weight (AVW) excised at the time of valve replacement is a flow-independent marker of stenosis severity. The objective of this study was to compare the AVW of patients with PLF and MG<40 mmHg with the AVW of patients with NF and MG≥40 mmHg.

METHODS AND RESULTS:

We recruited 250 consecutive patients undergoing valve replacement (Cohort A) for severe stenosis. Among them, 33 (13%) were in PLF [LVEF > 50% but stroke volume index (SVi) ≤ 35 mL/m2] with MG < 40 mmHg (PLF-LG group) and 105 (42%) were in NF (LVEF > 50% and SVi > 35 mL/m2) with MG ≥ 40 mmHg (NF-HG group). Despite a much lower MG (29 ± 7 vs. 53 ± 10 mmHg; P < 0.0001), patients in the PLF-LG group had a similar AVA (0.73 ± 0.12 vs. 0.69 ± 0.13; P = 0.19) compared with those in the NF-HG group. The AVW [median (interquartile): 1.90 (1.63-2.50) vs. 2.60 (1.66-3.32)] and prevalence of bicuspid phenotype (15 vs. 42%) were lower in the PLF-LG group than in the NF-HG group. However, AVWs analysed separately in the tricuspid and bicuspid valves were similar in both groups [tricuspid valves: 1.80 (1.63-2.50) vs. 2.30 (1.58-3.00) g; P = 0.26 and bicuspid valves: 2.72 (1.73-3.61) vs. 2.60 (2.10-3.55) g; P = 0.93]. When using cut-point values of AVW established in another series of non-consecutive patients (n = 150, Cohort B) with NF and concordant Doppler-echocardiographic findings, we found that the percentage of patients with evidence of severe stenosis in Cohort A was 70% in patients with PLF-LG and 86% in patients with NF-HG.

CONCLUSION:

The aortic valve weight data reported in this study provide evidence that a large proportion of patients with PLF and low-gradienthave a severe stenosis and that the gradient may substantially underestimate stenosis severity in these patients. A multi-parametric approach including all Doppler-echocardiographic parameters of valve function as well as other complementary diagnostic tests may help correctly identify these patients.

KEYWORDS:

Noninvasive pressure difference mapping derived from 4D flow MRI in patients with unrepaired and repaired aortic coarctation Authors: Fabian Rengier, Michael Delles, Joachim Eichhorn, Yoo-Jin Azad, Hendrik von Tengg-Kobligk, Julia Ley-Zaporozhan, Rüdiger Dillmann, Hans-Ulrich Kauczor, Roland Unterhinninghofen, Sebastian Ley

Noninvasive pressure difference mapping derived from 4D flow MRI in patients with unrepaired and repaired aortic coarctation Authors: Fabian Rengier, Michael Delles, Joachim Eichhorn, Yoo-Jin Azad, Hendrik von Tengg-Kobligk, Julia Ley-Zaporozhan, Rüdiger Dillmann, Hans-Ulrich Kauczor, Roland Unterhinninghofen, Sebastian Ley

Abstract
Purpose: To develop a method for computing and visualizing pressure differences derived from time-resolved velocity-encoded three-dimensional phase-contrast magnetic resonance imaging (4D flow MRI) and to compare pressure difference maps of patients with unrepaired and repaired aortic coarctation to young healthy volunteers.
Methods: 4D flow MRI data of four patients with aortic coarctation either before or after repair (mean age 17 years, age range 3-28, one female, three males) and four young healthy volunteers without history of cardiovascular disease (mean age 24 years, age range 20-27, one female, three males) was acquired using a 1.5-T clinical MR scanner. Image analysis was performed with in-house developed image processing software. Relative pressures were computed based on the Navier-Stokes equation.
Results: A standardized method for intuitive visualization of pressure difference maps was developed and successfully applied to all included patients and volunteers. Young healthy volunteers exhibited smooth and regular distribution of relative pressures in the thoracic aorta at mid systole with very similar distribution in all analyzed volunteers. Patients demonstrated disturbed pressures compared to volunteers. Changes included a pressure drop at the aortic isthmus in all patients, increased relative pressures in the aortic arch in patients with residual narrowing after repair, and increased relative pressures in the descending aorta in a patient after patch aortoplasty.
Conclusions: Pressure difference maps derived from 4D flow MRI can depict alterations of spatial pressure distribution in patients with repaired and unrepaired aortic coarctation. The technique might allow identifying pathophysiological conditions underlying complications after aortic coarctation repair.