Renal Arteries: Isotropic, High-Spatial-Resolution, Unenhanced MR Angiography with Three-dimensional Radial Phase Contrast

François, Christopher J.; Lum, Darren P.; Johnson, Kevin M.; Landgraf, Benjamin R; Bley, Thorsten Alexander; Reeder, Scott B.; Schiebler, Mark L.; Grist, Thomas M.; Wieben, Oliver

doi:10.1148/radiol.10100443

Cited by 50 publications

(36 citation statements)

References 23 publications

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“…A slab-selective radiofrequency excitation with a limited field of view, a variabledensity readout gradient, and sampling during the readout at twice the Nyquist rate were used to improve image quality of the lung parenchyma (23). We used an adaptive respiratory gating method with a respiratory bellows signal (23,24). Total imaging time was 5-6 minutes, depending on respiratory rate.…”

Section: Quantitative Image Analysesmentioning

confidence: 99%

Pulmonary Embolism Detection with Three-dimensional Ultrashort Echo Time MR Imaging: Experimental Study in Canines

Bannas¹,

Bell²,

Johnson³

et al. 2016

Radiology

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q RSNA, 2015 Purpose:To demonstrate the feasibility of free-breathing three-dimensional (3D) radial ultrashort echo time (UTE) magnetic resonance (MR) imaging in the simultaneous detection of pulmonary embolism (PE) and high-quality evaluation of lung parenchyma. Materials andMethods:The institutional animal care committee approved this study. A total of 12 beagles underwent MR imaging and computed tomography (CT) before and after induction of PE with autologous clots. Breath-hold 3D MR angiography and freebreathing 3D radial UTE (1.0-mm isotropic spatial resolution; echo time, 0.08 msec) were performed at 3 T. Two blinded radiologists independently marked and graded all PEs on a four-point scale (1 = low confidence, 4 = absolutely certain) on MR angiographic and UTE images. Image quality of pulmonary arteries and lung parenchyma was scored on a four-point-scale (1 = poor, 4 = excellent). Locations and ratings of emboli were compared with reference standard CT images by using an alternative free-response receiver operating characteristic curve (AFROC) method. Areas under the curve and image quality ratings were compared by using the F test and the Wilcoxon signed-rank test. Results:A total of 48 emboli were detected with CT. Both readers showed higher sensitivity for PE detection with UTE (83% and 79%) than with MR angiography (75% and 71%). The AFROC area under the curve was higher for UTE than for MR angiography (0.95 vs 0.89), with a significant difference in area under the curve of 0.06 (95% confidence interval: 0.01, 0.11; P = .018). UTE image quality exceeded that of MR angiography for subsegmental arteries (3.5 6 0.7 vs 2.9 6 0.5, P = .002) and lung parenchyma (3.8 6 0.5 vs 2.2 6 0.2, P , .001). The apparent signal-to-noise ratio in pulmonary arteries and lung parenchyma was significantly higher for UTE than for MR angiography (41.0 6 5.2 vs 24.5 6 6.2 [P , .001] and 10.2 6 1.8 vs 3.5 6 0.8 [P , .001], respectively). The apparent contrast-to-noise ratio between arteries and PEs was higher for UTE than for MR angiography (20.3 6 5.2 vs 15.4 6 6.7, P = .055). Conclusion:In a canine model, free-breathing 3D radial UTE performs better than breath-hold 3D MR angiography in the detection of PE and yields better image quality for visualization of small vessels and lung parenchyma. Free-breathing 3D radial UTE for detection of PE is feasible and warrants evaluation in human subjects.q RSNA, 2015

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Section: Quantitative Image Analysesmentioning

confidence: 99%

Pulmonary Embolism Detection with Three-dimensional Ultrashort Echo Time MR Imaging: Experimental Study in Canines

Bannas¹,

Bell²,

Johnson³

et al. 2016

Radiology

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“…Navigator-based respiratory gating, as well as continuously adapting respiratory gating with bellows, has allowed for 4D PC data sets to be collected during free breathing (11-13). However, respiratory gating further prolongs the already lengthy acquisitions.…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the high demands for spatial resolution and large volume coverage needed to assess the complicated anatomy of the abdominal vasculature (Figure 1) have hampered the use of 4D PC MRI in the abdomen. Radial undersampling has been promising as a means to overcome these limitations; radial undersampling has allowed for the assessment of renal flow in addition to the acquisition of high quality PC angiograms without the need for an external contrast agent (11, 12). Given the potential for artifacts arising from respiratory and peristaltic motion in abdominal exams, further evaluation is needed to assess the performance of 4D PC techniques in the abdomen.…”

Section: Introductionmentioning

confidence: 99%

Repeatability and Internal Consistency of Abdominal 2D and 4D Phase Contrast MR Flow Measurements

2013

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RATIONAL AND OBJECTIVES: The aim of this study was to assess the repeatability and internal consistency of flow measurements in the renal arteries and pararenal aorta with the use of standard 2D and novel 4D phase contrast (PC) magnetic resonance imaging (MRI). MATERIALS AND METHODS: Ten healthy volunteers were imaged with a radially-undersampled 4D PC technique centered over the renal arteries and with four 2D PC slices placed in the supra/infrarenal aorta and the left/right renal arteries; this MR exam was performed twice on each subject. Flow measurements in all four vessels were computed from 2D and 4D PC data sets. Student’s t-tests (p < 0.05) were used to assess differences between in-flow (suprarenal aorta) and out-flow (infrarenal aorta + left renal artery + right renal artery) for the 2D and 4D techniques, to compare in- and out-flow, and to compare repeated measurements of 2D and 4D flow measurements. RESULTS: No significant differences were found in repeated measurements of 2D (p = 0.15) or 4D (p = 0.39) data. No significant difference was found between 2D (3.4 ± 2.8 ml/cardiac cycle) and 4D (3.5 ± 2.7 ml/cardiac cycle) in- and out-flow differences (p = 0.88). Out-flow was greater than in-flow for 2D measurements (p = 0.003); no difference was found for 4D measurements. CONCLUSION: The 2D and 4D techniques demonstrated strong repeatability and internal consistency of flow measurements in the renal arteries and pararenal aorta.

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“…However, patients with compromised kidney function, including kidney transplant donors and recipients, should not receive gadolinium-based contrast agents because of the risk for nephrogenic systemic fibrosis [50]. Radial 4D flow MRI without the use of a contrast agent has been successfully applied to this vascular territory [8, 51]. Free-breathing acquisitions of 10 minutes provide angiograms of both renal arteries and veins with good correlation of diameter measures across various vessel sizes [8] as an alternative to CE-MRA (Fig.…”

Section: Emerging Abdominal Applicationsmentioning

confidence: 99%

“…Radial 4D flow MRI without the use of a contrast agent has been successfully applied to this vascular territory [8, 51]. Free-breathing acquisitions of 10 minutes provide angiograms of both renal arteries and veins with good correlation of diameter measures across various vessel sizes [8] as an alternative to CE-MRA (Fig. 7).…”

Section: Emerging Abdominal Applicationsmentioning

confidence: 99%

Emerging Applications of Abdominal 4D Flow MRI

Roldán‐Alzate

François

Wieben

et al. 2016

American Journal of Roentgenology

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OBJECTIVE Comprehensive assessment of abdominal hemodynamics is crucial for many clinical diagnoses but is challenged by a tremendous complexity of anatomy, normal physiology, and a wide variety of pathologic abnormalities. This article introduces 4D flow MRI as a powerful technique for noninvasive assessment of the hemodynamics of abdominal vascular territories. CONCLUSION Four-dimensional flow MRI provides clinicians with a more extensive and straightforward approach to evaluate disorders that affect blood flow in the abdomen. This review presents a series of clinical cases to illustrate the utility of 4D flow MRI in the comprehensive assessment of the abdominal circulation.

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Renal Arteries: Isotropic, High-Spatial-Resolution, Unenhanced MR Angiography with Three-dimensional Radial Phase Contrast

Cited by 50 publications

References 23 publications

Pulmonary Embolism Detection with Three-dimensional Ultrashort Echo Time MR Imaging: Experimental Study in Canines

Pulmonary Embolism Detection with Three-dimensional Ultrashort Echo Time MR Imaging: Experimental Study in Canines

Repeatability and Internal Consistency of Abdominal 2D and 4D Phase Contrast MR Flow Measurements

Emerging Applications of Abdominal 4D Flow MRI

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