Search

Background Beta-blockers are the recommended medical treatment for slowing ascending aorta (AAo) dilation in patients with bicuspid aortic valve (BAV). Wall shear stress (WSS) has been shown to promote endothelial cell dysfunction [1] and AAo WSS may play a role in aortic aneurysm growth. Time-resolved 3D phase contrast (4D flow) MRI allows for the quantification of 3D WSS regionally in the thoracic aorta. The aim of this study was to assess changes in thoracic aorta WSS associated with b-blocker therapy in BAV patients.

We present pre- and postoperative imaging findings in a 29-year-old man with a bicuspid aortic valve (BAV) with fusion of the right and left coronary leaflets and a 6.1 cm × 6.3 cm ascending aorta aneurysm (Figure 1). The patient underwent a valve-sparing aortic root replacement with a 34-mm Dacron graft and BAV repair with resection of the raphe of the fused leaflet and leaflet shortening of the noncoronary cusp. Figure 1. Sagital ( A ) and axial ( B ) preoperative MRI demonstrating a 6.1×6.3 cm ascending aorta (AAo) aneurysm. To better understand the preoperative flow characteristics in the large aneurysm and the impact of surgical repair and reconstruction on thoracic aorta hemodynamics, time-resolved 3-dimensional phase contrast (4D flow) MRI was performed before and after surgery. The MRI examinations (pre: 3.0 T Skyra, post: 1.5 T Avanto, Siemens, Germany) included both 4D flow MRI (velocity sensitivity pre:150 cm/s, post: 250 cm/s, spatial/temporal resolution pre: 3.14×2.13×3.2 mm3/39 ms, post: 2.88×2.13×2.15 mm3/38ms) and dynamic 2-D cine imaging of the heart (steady-state free precession, spatial/temporal resolution pre: 1.25×1.25×6 mm3/29 ms post:1.8×1.8×6 mm3/39 ms). The study was approved by the local institutional review board, and informed consent was obtained from the patient. Blood flow patterns within the thoracic aorta were visualized using time-resolved 3D pathlines to illustrate complex blood flow dynamics over the entire cardiac cycle (EnSight, CEI). In addition, 3D velocity streamlines drawn tangent to the time-resolved velocity field were used to illustrate instantaneous flow dynamics in the thoracic aorta. Forward and …

To investigate the influence of atherosclerotic plaques on femoral haemodynamics assessed by two-dimensional (2D) phase-contrast (PC) magnetic resonance imaging (MRI) with three-directional velocity encoding. During 1 year, patients with peripheral artery disease and an ankle brachial index

A sophisticated understanding of the rapidly changing field of oncology, including a broad knowledge of oncologic disease and the therapies available to treat them, is fundamental to the interventional radiologist providing oncologic therapies, and is necessary to affirm interventional oncology as one of the four pillars of cancer care alongside medical, surgical, and radiation oncology. The first part of this review intends to provide a concise overview of the fundamentals of oncologic clinical trials, including trial design, methods to assess therapeutic response, common statistical analyses, and the levels of evidence provided by clinical trials.

Background Cardiac Magnetic Resonance (CMR) imaging is increasingly recognized as the gold standard for evaluating left ventricular function (LVF). Measurement of LVF is typically done manually by tracing endocardial and epicardial borders on a stack of short axis (SA) cine images of the heart and is based on the modified Simpson assumption that the left ventricle approximates a spherical shape. A drawback of this method is that it is laborious and timeconsuming. The recent introduction of computer-based inline VF software that allows for automatic assessment raised the prospect for significant reductions in CMR post processing times. Initial results have found that fully automatic analysis is unreliable as compared to manual calculations. However, usually only 1 or 2 contours are inaccurate using the automatic software suggesting that, if these are corrected manually, a semi-automatic approach may be helpful. This study sought to compare fully automatic inline VF tracking to this semi-automatic method using the manual technique as gold standard.

Background Cardiac MR (CMR) is the accepted gold standard for the assessment of myocardial scar and biventricular systolic function. Bright blood cine imaging with phase-contrast mitral inflow assessment has shown promise for the evaluation of left ventricular (LV) diastology. The purpose of this study is to evaluate the accuracy of LV diastolic function grading by CMR, using Doppler echocardiography as the reference standard. We hypothesize that quantitative CMR analysis of diastolic function coupled with left atrial volume (LAV) assessment is accurate in characterizing LV diastology. Methods 83 patients without mitral valve disease (47 men, average age 53 years) underwent CMR imaging on a 1.5T scanner for evaluation of myocardial viability or infiltrative heart disease. All patients underwent 2-D phase-contrast (PC) imaging of the mitral valve (TR/TE 48/2.2, FA 30 degrees, VENC 80 cm/s, 20 phases, bw 554). Brightblood (BB) 4- and 2-chamber cine imaging was performed (TR/TE 13/1.1, FA 69 degrees, 40 to 50 phases, BW 933) for lateral mitral annular and left atrial volume (LAV) assessment. Peak E and A velocities were obtained from PC data. 4-chamber BB cine images were analyzed using prototype software evaluating deformation fields to automatically identify and track the mitral base plane at the lateral and septal insertions, extracting lateral e’ values (Siemens Corp., Corporate Technology, Princeton, New Jersey). LAV was obtained using the lengtharea method. LV diastolic function was graded using established echocardiographic criteria. Differences in means were assessed using the student’ st -test. Results

Background Non-ischemic dilated cardiomyopathy (DCM) is a relatively common cause of left ventricular dysfunction. Microscopic scar may be a cause of regional and global left ventricular dysfunction in DCM patients. The aim of this study was to evaluate changes in regional myocardial structure, function, and dyssynchrony using a novel noninvasive MR imaging protocol. Methods Eleven patients with suspected non-ischemic cardiomyopathy underwent cardiac MRI (CMR) on a 1.5T magnet (Magnetom Avanto or Aera, Siemens Healthcare, Erlangen, Germany). In addition to the conventional CMR viability protocol, patients underwent both tissue phase mapping (TPM) and T1 mapping with a modified look-locker inversion recovery (MOLLI) technique pre and between 10 and 25 minutes post 0.2 mmol/kg adminstration of an extracellular gadolinium agent. These sequences were performed through the left ventricle in the short axis orientation at basal, mid-chamber, and apical levels. The hematocrit was collected within 48 hours of the CMR to calculate segmental ECV values as described by Kellman, et al., as a marker of microscopic fibrosis. TPM analysis was used to determine the degree of segmental wall motion abnormality. Radial, longitudinal and absolute velocities

Persons with human immunodeficiency virus (HIV) have greater risks for myocardial infarction and sudden cardiac death (SCD) than the general population. Associations between coronary artery disease (CAD) and myocardial fibrosis - a mediator of SCD - in the setting of HIV are unknown. We hypothesized

Summary The purpose of the study is to evaluate a fully automated motion corrected first pass myocardial perfusion (FPMP) MRI with semi quantitative perfusion parameter maps in patients with suspected ischemic heart disease. Background Coronary heart disease is the leading cause of death and disability in the US. FPMP MRI is increasingly used to assess ischemic heart disease; however respiratory motion is one of the major problems for myocardial blood flow quantification. An algorithm for motion correction, surface coil correction, temporal denoising and robust pixel-wise parameter map generation model was previously desribed [Xue H et al MICCAI 2009).This work evaluates automated workflow in a clinical setting to diagnose ischemic heart disease comparing free breathing and motion correcteted images and corresponding pixel-wise parameter map. Methods Stress and rest FPMP images were acquired using a 1.5T scanner (MAGNETOM Avanto, Siemens Healthcare) in 39 patients with suspected ischemic heart disease. Short axis slices were acquired during infusion of 0.075 mMol/kg of Gadolinium (Magnevist, Bayer HealthCare Pharmaceuticals, USA) and adenosine (Adenoscan, AstellasPharma, USA) infusion (0.14 mg/kg/min; duration: 4 min) was administrated to induce stress. Free breathing, motion-corrected images and corresponding perfusion maps were assessed by 2 radiologists independently using the AHA 16 model and evaluated using a four point Likert scale (poor to excellent) to evaluate image quality and confidence level in presence or absence of hypo-perfusion regions. Upslope index of both free breathing and motion corrected images during stress and rest were manually calculated in nonischemic and ischemic areas and compared to the corresponding pixel-wise parameter map generated based on motion corrected images. FPMP MRI results were subsequently compared to coronary angiogram, stress echocardiography, or SPECT.

Background To quantify myocardial T2 value in patients with myocarditis and correlate the distribution of abnormal T2 values with the extent of macroscopic late gadolinium enhancement (LGE). Methods 25 patients with myocarditis were retrospectively evaluated for the utility of T2 mapping in diagnosing myocarditis. Patients with elevated troponins, negative coronary angiogram, and atypical LGE were diagnosed as acute myocarditis. Patients with normal troponins and macroscopic LGE at the time of cardiac MRI were diagnosed as remote myocarditis. As per our institutional protocol, T2 mapping sequences were performed in all cases with suspected myocarditis in addition to standard LGE images on 1.5 T scanner (Magnetom Aera and Avanto, Siemens medical solutions). T2 mapping was performed on three short axis images (base, mid chamber, and apex), yielding 16 myocardial segments for analysis (AHA segments). Single 4 chamber view image was obtained in addition. Minimum, peak and mean segmental T2 values were calculated by the first reader. Average segmental T2 values were documented along with documentation of the number of segments with elevated T2 values. The presence or absence of LGE was documented by a second reader blinded to the T2 results. Average segmental T2 values were then correlated with troponin levels at the time of the MRI examination. Results In patients with acute myocarditis, mean T2 values were elevated in segments showing LGE (average T2 value of 70 msec). The T2 values were also elevated in myocardial segments with no macroscopic LGE (avg 60 msec). On an average, there were 6 additional segments that showed elevated T2 values and no macroscopic LGE. In patients with remote myocarditis, the T2 values were normal in areas of LGE.

Magnetic resonance imaging (MRI) is intrinsically sensitive to flowing blood. The earliest investigators of MRI recognized that blood flow altered the intraluminal magnetic resonance signal. MRI techniques in imaging blood flow have been principally directed toward interrogation of the arterial system. However, the same techniques that have made magnetic resonance angiography such a useful clinical tool have also been applied to the venous system.

Magnetic resonance angiography (MRA) is an accepted modality for arterial imaging of the lower extremities. Lower extremity MRA (LE-MRA) primarily relies on subtracted gadolinium-enhanced three-dimensional spoiled gradient echo sequences. The modality has evolved with the evolution of low-dose time-resolved gadolinium-enhanced angiography sequences. LE-MRA has also benefited from the continued evolution of noncontrast angiography techniques, enabling safe and accurate arterial imaging in patients with renal insufficiency.

MRI is the accepted gold standard for assessment of left ventricular systolic function; however, no standards are available to assess diastolic function at MRI. E/A and E/e’ ratios are currently used in echocardiography to evaluate left ventricular diastolic function. Measuring these ratios with phase contrast MRI may provide a complementary approach to assessing left ventricular function.

A novel method for determining a correlate of Tissue Doppler Imaging (TDI) parameters from cine TrueFisp data. Using the velocity of automatically identified and tracked landmarks,time/velocity data and hence s', e' and a' can be derived.

To analyze the effectiveness of pre-study questionnaires in identifying at-risk patients as well as estimate the prevalence of chronic kidney disease (CKD), nephrogenic systemic fibrosis (NSF) risk factors, and other co-morbidities in patients scheduled to undergo magnetic resonance angiography (MRA) gadonlinium-based contrast agents (GBCA) studies.

Depiction of pericardial disease using Cardiac MR can bedifficult, even in the presence of significant pericardialthickening. One essential requirement is the homogenousand consistent suppression of fat to facilitate the distinc-tion of pericardial fat from parietal pericardium. The con-ventional chemical-shift selective fat-saturationapproaches often result in non-uniform fat-suppressiondue to field variations at tissue interfaces. Alternativemethods such as the use of inversion recovery reduce sig-nal strength in the resultant images. Multi-echo Dixonapproaches utilizing iterative decomposition have beenshown to provide robust fat-water separation even in thepresence of large field inhomogeneities and are likely tobe particularly beneficial in this area of pericardial imag-ing.

Pulmonary MRA generates high-resolution images of the pulmonary veins (PV) and left atrium (LA), permitting characterization of complex PV anatomy, which is useful in electrophysiologic PV catheter ablation, a proven technique for the treatment of paroxysmal atrial fibrillation (PAF). The purpose of this study was to determine if pre-ablative pulmonary MRA with intra-ablative viewing facilitates ablation by reducing fluoroscopy time. We studied the morphology of the LA and PV at 1.5T (Magnetom Sonata, Siemens Medical Solutions, Erlangen Germany) with breath-held gadolinium-enhanced 3D MRA in 7 patients with PAF undergoing PV ablation. Data was volume rendered (VR) on a stereoscopic workstation. PV ostial diameter and cross-sectional area measurements were obtained on multi-planar reformatted (MPR) images. VR datasets were converted into digital movies and were viewed on a laptop computer adjacent to real-time fluoroscopic images. Fluoroscopy times for patients undergoing pre-ablative MPA mapping were compared with a cohort of 22 consecutive patients diagnosed with PAF who underwent catheter ablation without pre-ablative MRA planning. Mean PV ablation fluoroscopic time with MRA planning versus fluoroscopic imaging alone were 84±20 minutes and 114±20 minutes respectively. Pre-ablative MRA planning resulted in a significant mean fluoroscopy time savings of 26% (p

Magnetic resonance (MR) angiography is becoming widely accepted in the diagnosis of vascular diseases. When used for evaluation of arterial stenoses, aneurysm, thrombosis, or occlusion, MR angiography is a robust and accurate technique. Traditional techniques for contrast-enhanced magnetic resonance angiography (MRA) offer the benefit of high spatial resolution in characterizing vascular malformations, but have lacked the temporal resolution to describe dynamic flow events. The purpose of this project is to demonstrate the potential role of a novel technique, sub-second MRA, in the evaluation of abdominal arteriovenous malformation.

Background Wall shear stress (WSS) may be associated with the onset and development of aortopathy in the presence of bicuspid aortic valve (BAV) [Michelena, JAMA (2011)]. The use of ‘aortic atlases’ of 3D WSS vectors allows for systematic analysis of WSS differences between large patient cohorts. In this study, a comparison is performed between WSS atlases of BAV patients, BAV patients with aortic dilation, patients with BAV stenosis, and healthy controls with tricuspid valves. The aim is to test the hypothesis that WSS atlases can identify regions of significantly altered WSS that are associated with different expression of BAV and aortopathy.

Background The use of gated CMR can be limited by motion artifacts secondary to cardiac and respiratory motion. Imaging is especially challenging in patients with arrhythmias or those who cannot perform adequate breath-holds. Realtime CMR is a non-gated technique that has been successfully applied in scenarios where standard segmented acquisitions break down. In this study, we sought to accelerate real-time acquisition by using sparse sampling with an iterative SENSE reconstruction.

Background Changes in myocardial strain have been shown to precede onset of systolic dysfunction in patients with cardiomyopathy. Traditionally performed with echocardiography, acoustic windows can limit strain evaluation. Preliminary work has shown good agreement between myocardial strain derived from deformation field analysis at balanced steady-state free-precession (bSSFP) cine MRI and speckle tracking echocardiography. The application of a novel prototype iterative SENSE reconstruction with L1 regularization (IRSENSE) to highly accelerated segmented bSSFP cine acquisitions can maintain or improve the effective temporal resolution with a shorter breath-hold. The purpose of this study is to evaluate left- and right-ventricular stain analysis from bSSFP cine acquisitions using conventional GRAPPA and highly accelerated T-PAT with IR-SENSE. We hypothesize that myocardial strain parameters derived from accelerated T-PAT cine acquisitions with IR-SENSE are similar to those obtained using conventional segmented bSSFP with comparable effective temporal resolutions.

Background Alterations in systolic blood flow are a characteristic finding in patients with obstructive hypertrophic cardiomyopathy (HCM). Echocardiography is the gold standard for hemodynamic assessment in HCM, but this technique is generally limited to measurement of the left ventricular outflow tract (LVOT) pressure gradient and may not provide a complete description of the hemodynamic impact of the disease. In this study, we sought to employ time-resolved, three-dimensional phase contrast (4D flow) MRI to visualize and quantify 3D blood flow patterns in the LVOT and ascending aorta (AAo) in patients with obstructive and nonobstructive HCM. Methods Obstructive (n = 12) and non-obstructive (n = 18) HCM patients as well as 10 normal volunteers were included in this IRB-approved study. Obstruction was defined as LVOT pressure gradient > 30 mmHg on patients’ most recent echocardiography study (ΔPecho). Septal thickness, LVOT diameter and septum/free wall ratio were measured on SSFP cine MRI. 4D flow MRI data analysis included correction for eddy currents and velocity aliasing, followed by flow visualization and quantification in dedicated software (EnSight, CEI, Apex, NC). 3D blood flow patterns within the LVOT and AAo were graded for the presence of helical flow (absent = 0, mild/moderate = 1, severe = 2) by two observers blinded to diagnosis, and the results were averaged. MRI-measured pressure gradient (ΔPMRI) was calculated from the peak systolic 3D blood velocity profile within the LVOT using the simplified Bernoulli equation. (Figure 1) The Mann-Whitney U test was used to compare groups and Spearman’ s( rS) or Pearson’s (r) correlations were used as appropriate. Results

Background Patients with aortic dilation often present an eccentric transvalvular flow jet. The angle of the flow jet from the aorta centerline, or the flow jet angle (FJA), has been reported as a risk factor in bicuspid aortic valve patients [1]. In recent studies we introduced a the jet shear layer detection (JSLD) method for the automated characterization of transvalvular flow structure across the aortic valve [2,3]. The objective of this study was to evaluate FJA in patients with aortic dilation using the 3D JSLD structure obtained from 4D flow MRI.

Background Breath-hold (BH) segmented TURBO FLASH (TFL) is currently used as the gold standard technique to evaluate delayed enhancement (DE) of the myocardium, typically with a phase sensitive inversion recovery (PSIR) approach (1). However, many patients are unable to perform adequate breath-holding resulting in poor image quality and limited diagnostic yield. Free breathing (FB) single shot steady state free precession (SSFP) is used as an alternative approach however respiratory motion artifact with resultant blurring may affect visualization of smaller myocardial scars. FB motion corrected (MOCO) single shot SSFP with averaging (2) has been shown to be equal or superior in detecting myocardial infarction (3), particularly in vulnerable patients. For FB MOCO sequences to replace current BH techniques in the detection of DE, they must be sensitive to the detection of both ischemic and non-ischemic patterns of delayed enhancement.

Background The purpose of this study was to assess the impact of aortic valve morphology on aortic 3D blood flow dynamics and wall shear stress (WSS) in normal and a wide range of congenitally altered aortic valves ranging from unicuspid to quadricuspid morphology. Methods In-vivo aortic 3D hemodynamics were evaluated by MRI in 17 patients with unicuspid (n=3), bicuspid (n=9, 3 true bicuspid, 3 right-left (RL) coronary leaflet fusion, and 3 right-non (RN) coronary leaflet fusion), trileaflet (n=3), and quadricuspid aortic valves (n=2). Valve morphology and dynamics were assessed using 2D CINE MRI. Aortic blood flow was measured using ECG and respiration synchronized 4D flow MRI with full volumetric coverage of the aorta. Data analysis included co-registered visualization of aortic valve morphology with systolic 3D blood flow and grading of valve-specific aortic out-flow patterns. The influence of valve geometry on aortic hemodynamics was quantified by calculation of valve flow angle and segmental distribution of ascending aorta WSS. Results All congenitally altered valves showed marked flow derangement, elevated velocity jets along the aortic wall and distinct flow impingement locations. While all RLBAV valves were associated with flow jets directed towards the right anterior aortic wall, RN-fusion and unicuspid valves showed jet patterns towards the right-posterior wall. Quantitative analysis revealed higher flow angles for unicuspid, true BAV, RN-BAV, RL-BAV, and quadricuspid

Background Altered aortic hemodynamics associated with bicuspid aortic valve (BAV) have been implicated in the development of aortopathy in patients with congenitally altered valves[1]. Most studies have focused on the most common “right-left” bicuspid aortic valve (RL-BAV) fusion pattern [2]. This study assessed the effects of valve morphology on aortic 3D blood flow in cohorts with the most common RL-BAV fusion, less common right-noncoronary (RNC-BAV), and normal trileaflet valves.

Background Although contrast-enhanced first-pass MRA (FP-MRA) is frequently used to visualize the thoracic vasculature, it may not be ideal for the assessment of the aortic root due to poor image quality and motion artifact. Bloodpool contrast agents remain within the intravascular space for several hours, allowing vessels to be imaged longer and therefore improving spatial resolution. The purpose of this study is to compare steady-state magnetic resonance angiography (SS-MRA) following injection of a blood-pool contras agent to first-pass MR angiography (FP-MRA) in adults with thoracic aortic disease. Methods 25 patients (14 men, 11 women) with suspect thoracic aortic disease disease underwent MRA on a 1.5 T scanner (Magnetom Aera and Avanto; Siemens Medical Solutions). The MRA protocol consisted of FP-MRA followed by SS-MRA after intravenous injection of gadofosveset trisodium (Ablavar, Lantheus Medical Imaging). FP-MRA consisted of a breath-held ECG-gated FLASH acquisition in a sagittal oblique orientation with the following imaging parameters: TR/TE: 2.8/1.0, flip angle 25°, FOV 343x500 mm, matrix 264x512, slice thickness 1.5 mm, voxel size 1.3 x 1.0 x 1.0 mm, GRAPPA x 2, 20 second acquisition. 0.03 mmol/kg of gadofosveset was injected intravenously at 1cc/sec in an antecubital vein. Contrast bolus timing was achieved using care bolus technique. SS-MRA consisted of free-breathing ECGgated IR-FLASH and IR-SSFP in a sagittal oblique orientation. IR-FLASH had the following parameters: TR/TE/TI: 3.5/1.5/260, flip angle 18°, and IR-SSFP had: TR/TE/TI: 3.3/1.5/260, flip angle 70°. Both sequences had FOV 326x380, matrix 440x512, slice thickness 1.5 mm, voxel 0.7 x 0.7 x 1.0 mm, GRAPPA x 2, and 3 minute acquisition. Respiratory gating was achieved using a navigator acquisition with an average acceptance window of 35%. For quantitative analysis, orthogonal dimensions of the thoracic aorta were measured at several locations. Signal-to-noise ratio (SNR) was also measured for both techniques by placing regions of interest in the aortic root and the ascending aorta. For qualitative analysis, two independent reviewers evaluated both FP-MRA and SS-MRA images separately. The aortic root and the ascending aorta were scored on an image quality scale of 1-4.

Objective To evaluate the potential clinical utility of T2 quantitative mapping for myocardial edema in acute disease pathology - myocarditis, myocardial infarction, TakoTsubo cardiomyopathy, and transplant rejection. Background Edema is ag eneric tissue response to acute myocardial injury and, therefore; a potential marker of impending tissue damage. Currently in clinical use, T2 weighted imaging provides a qualitative technique in assessing myocardial edema. We hypothesize that quantitative T2 mapping in patients with suspected cases of myocarditis, myocardial infarction (AMI), and cardiac transplant rejection will provide a more sensitive and specific diagnostic prediction than with T2W imaging, and add to other imaging techniques. Method

Right heart catheterization (RHC) is required for definitive diagnosis of pulmonary hypertension (PH) and serial echocardiograms or RHC are necessary for long term disease management. However, RHC is invasive, costly and risky for the patient[1]. Echocardiography is a non-invasive alternative but recent studies have questioned its accuracy and reproducibility in the setting of PH[2]. Cardiac magnetic resonance (CMR) has been shown to be helpful in distinguishing PH patients from healthy subjects through visualization of morphologic features such as right atrial and ventricular enlargement, tricuspid regurgitation and abnormal interventricular septal motion[3]. CMR has the additional advantage of producing quantitative measures of right ventricular function, which may have added value in assessing PH.

Background To systematically investigate the performance and interobserver variability of a new standardized workflow for the analysis of aortic hemodynamics based on 4D-flow MRI in a study with 30 subjects. The semi-automated workflow was developed to ensure faster and standardized data analysis including systematic placement of analysis planes, 3D-flow visualization, and quantification of standard clinical flow parameters.

Cardiac MRI is the accepted gold standard for the assessment of left ventricular systolic function. However, no standards exist for the MRI assessment of left ventricular diastolic function. We hypothesize that the superior morphologic assessment enabled by ultrafast ECG gated cine TrueFISP imaging will enable assessment of left ventricular diastolic function.

Background Time-resolved three-dimensional phase contrast (4D flow) MRI allows for visualization of three-dimensional cardiovascular anatomy and pulsatile flow with full volumetric coverage in a single, easy to prescribe 3D acquisition. The technique provides comprehensive flow visualization and permits retrospective flow quantification at any user-defined region of interest. [1] To our knowledge, no center has incorporated 4D flow MRI as a part of standard clinical cardiovascular MRI (CMR). The goals of this study include: 1) reporting on the incorporation of 4D flow MRI acquisition and processing as part of clinical CMR workflow and 2) better understanding the clinical impact of 3D flow visualization and retrospective flow quantification derived from 4D flow MRI in CMR.

Background Transcatheter aortic valve replacement (TAVR) has emerged as an accepted therapeutic option for moderate and high-risk patients with severe aortic stenosis. In addition to vessel caliber, the presence and configuration of vascular calcifications by the iliofemoral access site is part of routine pre-interventional assessment with CTA and catheter angiography. Non-contrast MR angiography has been proven useful for evaluation of lower extremity peripheral vascular disease, however it cannot identify vascular calcifications using currently available sequences. Neutral contrast 3D and 3D point-wise encoding time reduction (PETRA) are novel MR techniques that can detect vascular calcifications and enable projection-like displays for review, similar to CT. We hypothesized that these techniques, associated with noncontrast Quiescent Interval Slice-Selective (QISS) MRA may be useful alternatives for pre-surgical planning in patients considered for TAVR.

Methods IRB approval was obtained. Twenty patients (age: 54.8 ± 14 years, M:F = 15:5) undergoing non-emergent CMR assessment for myocardial pathology were consecutively recruited. Nine healthy volunteers (age: 44.3 ± 14 years, M:F = 6:3) were also imaged. CMR was performed at 1.5T (MAGNETOM Aera, Siemens Healthcare, Erlangen, Germany). The examination included acquisition of standard segmented SSFP (iPAT2) (GRAPPA accel factor 2, TR 40 msec, 2.1 × 2.1 × 10 mm) cine and two accelerated segmented SSFP acquisitions (TPAT accel factor 4, TR 37.7 msec, 2.1 × 2.1 × 6 mm), one with an investigational prototype inline iterative k-t-sparse SENSE reconstruction with L1 regularization along one spatial and temporal dimension (TPAT4i) (1)and the other with conventional SENSE reconstruction (TPAT4). Each technique was used to acquire a three(3Ch), four-chamber (4Ch), and short axis (SA) series in identical slice positions (Figure 1), with SA coverage of the entire left ventricle (LV) with 10 mm interslice gaps. Individual slice scan times were recorded. Quantitative LV functional analysis was performed. A reviewer blinded to acquisition type scored images for overall image quality, noise, and artifacts using a 5-point Likert scale. Continuous variables were compared between groups using a paired t-test, and ordinal variables were compared using a Wilcoxon signed-rank test.