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Yoon WJ, Rodriguez VM, Lee CJ. Insights on Bridging Stent Grafts in Fenestrated and Branched Aortic Endografting. Vasc Specialist Int 2021; 37:14. [PMID: 34135130 PMCID: PMC8209487 DOI: 10.5758/vsi.210025] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/27/2021] [Accepted: 05/28/2021] [Indexed: 11/20/2022] Open
Abstract
Major branches of the aortic arch and visceral aorta pose a particular challenge for endovascular repair of aneurysms involving these regions. To preserve perfusion through these essential branches, fenestrated and branched endografts have been used. Current fenestrated and branched aortic endografts have evolved into modular devices in which the aortic main body provides appropriate access to the target branch vessel either through reinforced fenestrations or directional cuffs as the hinge point for bridging stent grafts (BSGs). BSGs are used to connect the aortic main body and target branch vessel, and must provide both unhindered flow and a seal. Appropriate selection of BSG for target vessels in branched and fenestrated endovascular aortic repair is critical for technical success and durability. At present, there are no dedicated devices for use as BSGs, and a variety of stent grafts are currently used off-label. In this report, we review the available published series on the performance of presently available BSGs in relation to their design and selection.
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Affiliation(s)
- William J Yoon
- Division of Vascular Surgery, Department of Surgery, University of California-Davis, Sacramento, CA, USA.,Section of Vascular Surgery, Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Victor M Rodriguez
- Division of Vascular Surgery, Department of Surgery, University of California-Davis, Sacramento, CA, USA.,Division of Cardiothoracic Surgery, Department of Surgery, University of California-Davis, Sacramento, CA, USA
| | - Cheong Jun Lee
- Division of Vascular Surgery, Department of Surgery, NorthShore University HealthSystem, University of Chicago Pritzker School of Medicine, Evanston, IL, USA
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Huang IKH, Renani SA, Morgan RA. Complications and Reinterventions After Fenestrated and Branched EVAR in Patients with Paravisceral and Thoracoabdominal Aneurysms. Cardiovasc Intervent Radiol 2018; 41:985-997. [PMID: 29511866 DOI: 10.1007/s00270-018-1917-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 02/21/2018] [Indexed: 12/17/2022]
Abstract
The application of endovascular strategies to treat aneurysms involving the abdominal and thoracoabdominal aorta has evolved significantly since the inception of endovascular aneurysm repair. Advances in endograft technology and operator experience have enabled the management of a wider spectrum of challenging aortic anatomy. Fenestrated endovascular and branched endovascular aneurysm repair represent two technical innovations, which have expanded endovascular treatment options to include patients with paravisceral and thoracoabdominal aortic aneurysms. Although similar in many ways to standard aortic endografts, fenestrated and branched endografts have specific short- and long-term complications due to their unique modular endograft design and their sophisticated deployment mechanisms. This article aims to examine the commonly encountered complications with these devices and the endovascular reintervention strategies.
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Affiliation(s)
- Ivan Kuang Hsin Huang
- Department of Radiology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.
| | | | - Robert A Morgan
- Department of Radiology, St. George's Hospital NHS Trust, London, UK
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3
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Abstract
The authors report a case of renal artery stent restenosis exacerbated by the likely displacement of multiple bare metal stents that had been contiguously deployed 3 months previously. The unusual features of this case are discussed along with putative mechanisms of stent displacement in visceral arteries. The restenotic disease was successfully treated with excimer laser atherectomy and cutting balloon atherotomy.
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Affiliation(s)
- Adil Waheed
- Department of Endovascular Medicine, Deborah Heart and Lung Center, Browns Mills, NJ 08015, USA
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4
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Suh GY, Choi G, Herfkens RJ, Dalman RL, Cheng CP. Three-Dimensional Modeling Analysis of Visceral Arteries and Kidneys during Respiration. Ann Vasc Surg 2016; 34:250-60. [PMID: 27116907 DOI: 10.1016/j.avsg.2016.04.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 02/17/2016] [Accepted: 04/14/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND Visceral arteries are commonly involved in endovascular repair of complex abdominal aortic aneurysms (AAAs). To improve repair techniques and reduce long-term complications involving visceral arteries, it is crucial to understand in vivo arterial geometry and the deformations due to visceral organ movement with respiration. This study quantifies deformation of the celiac, superior mesenteric (SMA), and renal arteries during respiration and correlates the deformations with diaphragmatic excursion. METHODS Sixteen patients with small AAAs underwent magnetic resonance angiography during inspiratory and expiratory breathholds. From geometric models of the aorta and visceral arteries, vessel length, branch angle, curvature, and positions were computed, along with degree of diaphragmatic excursion as indicated by kidney translation. RESULTS From inspiration to expiration, the celiac artery exhibited axial shortening of 4.8 ± 6.4% (P < 0.001) and a mean curvature increase of 0.03 ± 0.02 mm(-1), greater than other visceral arteries (P < 0.01). With expiration, the SMA, left and right renal arteries (LRA and RRA) angled upward by -9.8 ± 6.4°, -6.4 ± 6.4°, and -5.2 ± 5.0°, respectively (P < 0.005). All vessels translated superiorly (P < 0.0005) and posteriorly (P < 0.01), and the SMA translated rightward additionally (P < 0.005). The left and right kidneys translated by 22 ± 9 mm and 21 ± 9 mm, mostly superiorly (P < 0.001). Translations of all visceral arteries were moderately correlated to the right kidney (R > 0.50). Correlation of the LRA with the left kidney was greater than that of the RRA with the right kidney. CONCLUSIONS The celiac artery exhibited less branch angle change, and greater axial and curvature deformations than the other visceral arteries, due to the vicinity to the liver and influence of the median arcuate ligament. Correlation between visceral arteries and kidney translations revealed that diaphragmatic excursion affects vessel mobility. Weaker correlation of the RRA to the right kidney indicates mechanical shielding from the inferior vena cava.
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Affiliation(s)
- Ga-Young Suh
- Department of Surgery, Stanford University, Stanford, CA.
| | - Gilwoo Choi
- Department of Surgery, Stanford University, Stanford, CA
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5
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Wang LC, Scott DJ, Clemens MS, Hislop SJ, Arthurs ZM. Mechanism of Stent Failure in a Patient with Fibromuscular Dysplasia following Renal Artery Stenting. Ann Vasc Surg 2015; 29:123.e19-21. [DOI: 10.1016/j.avsg.2014.08.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 07/03/2014] [Accepted: 08/29/2014] [Indexed: 11/30/2022]
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6
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Zhang Y, Xing Z, Liu Y, She D, Zeng Z, Cao D. Nonenhanced renal MR angiography using steady-state free precession (SSFP) and time-spatial labeling inversion pulse (Time-SLIP): repeatability and comparison of different tagging location. ABDOMINAL IMAGING 2014; 39:1000-8. [PMID: 24687245 DOI: 10.1007/s00261-014-0126-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To prospectively determine the repeatability of noncontrast-enhanced renal arterial angiography with steady-state free precession (SSFP) and time-spatial labeling inversion pulse (Time-SLIP), and to compare the visibility of renal artery and its branches when different locations of tagging pulse were placed. METHODS Thirty-six young healthy volunteers were enrolled in this study and were twice examined by noncontrast-enhanced renal arterial angiography with SSFP and Time-SLIP in 1.5T MR scanner. Measurement error and repeatability were assessed for each of the five major parameters [vessel-to-kidney ratio (VKR), grade of renal arterial branching, grading of image quality, diameter and area of the main renal artery] using the Bland-Altman plot. Two independent observers recorded the values of the parameters; Inter- and intra-observer agreement was assessed using the intraclass correlation coefficients (ICCs). The same parameters, acquired at the tagging pulse placed just above the superior poles of both kidneys or closer to the main renal arteries, were compared using the Wilcoxon signed-rank test. RESULTS Grading of arterial branching by the Time-SLIP SSFP was satisfactorily reproducible with the mean score of greater 3.83 indicating the visibility of branches within the renal parenchyma. The image quality was excellent for Segment I (the main trunk of renal artery) and good for Segment II (segmental branches pre renal parenchyma) and III (vessels within the renal parenchyma) with a satisfying repeatability between two examinations and a good inter- and intra-observer agreement. The ICCs for the inter- and intra-observer measurements of both diameter and area of the main arteries ranged from 0.781 to 0.934, indicating very good agreement. The repeatability of VKR was poor between the two examinations and at the two different tagging pulse locations. The position of tagging pulse in the origination of the main renal arteries was better than in the superior poles of kidneys as it provided a better visualization of arterial branches. CONCLUSION Noncontrast-enhanced renal artery angiography with SSFP and Time-SLIP yields reliable and reproducible visualization of normal renal arteries. Localization of the tagging pulse closer to the main renal arteries provides better visibility of renal artery and its branches than the tag placement just above the superior poles of both kidneys.
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Affiliation(s)
- Yuyang Zhang
- Department of Radiology, First Affiliated Hospital of Fujian Medical University, 20 Cha-Zhong Road, Fuzhou, 350005, Fujian, China
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Xie Y, Fan Z, Saouaf R, Natsuaki Y, Laub G, Li D. Adaptive online self-gating (ADIOS) for free-breathing noncontrast renal MR angiography. Magn Reson Med 2014; 73:312-7. [PMID: 24478221 DOI: 10.1002/mrm.25121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 12/15/2013] [Accepted: 12/16/2013] [Indexed: 11/11/2022]
Abstract
PURPOSE To develop a respiratory self-gating method, adaptive online self-gating (ADIOS), for noncontrast MR angiography (NC MRA) of renal arteries to overcome some limitations of current free-breathing methods. METHODS A NC MRA pulse sequence for online respiratory self-gating was developed based on three-dimensional balanced steady-state free precession (bSSFP) and slab-selective inversion-recovery. Motion information was derived directly from the slab being imaged for online gating. Scan efficiency was maintained by an automatic adaptive online algorithm. Qualitative and quantitative assessments of image quality were performed and results were compared with conventional diaphragm navigator (NAV). RESULTS NC MRA imaging was successfully completed in all subjects (n = 15). Similarly good image quality was observed in the proximal-middle renal arteries with ADIOS compared with NAV. Superior image quality was observed in the middle-distal renal arteries in the right kidneys with no NAV-induced artifacts. Maximal visible artery length was significantly longer with ADIOS versus NAV in the right kidneys. NAV setup was completely eliminated and scan time was significantly shorter with ADIOS on average compared with NAV. CONCLUSION The proposed ADIOS technique for noncontrast MRA provides high-quality visualization of renal arteries with no diaphragm navigator-induced artifacts, simplified setup, and shorter scan time.
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Affiliation(s)
- Yibin Xie
- University of California, Los Angeles, Department of Bioengineering, Los Angeles, California, USA.,Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Department of Biomedical Sciences, Los Angeles, California, USA
| | - Zhaoyang Fan
- Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Department of Biomedical Sciences, Los Angeles, California, USA
| | - Rola Saouaf
- Cedars-Sinai Medical Center, Department of Imaging, Los Angeles, California, USA
| | | | - Gerhard Laub
- Siemens Medical Solutions, Los Angeles, California, USA
| | - Debiao Li
- University of California, Los Angeles, Department of Bioengineering, Los Angeles, California, USA.,Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Department of Biomedical Sciences, Los Angeles, California, USA
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Suh GY, Choi G, Herfkens RJ, Dalman RL, Cheng CP. Respiration-induced deformations of the superior mesenteric and renal arteries in patients with abdominal aortic aneurysms. J Vasc Interv Radiol 2013; 24:1035-42. [PMID: 23796090 PMCID: PMC3694359 DOI: 10.1016/j.jvir.2013.04.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 04/01/2013] [Accepted: 04/02/2013] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To quantify respiration-induced deformations of the superior mesenteric artery (SMA), left renal artery (LRA), and right renal artery (RRA) in patients with small abdominal aortic aneurysms (AAAs). MATERIALS AND METHODS Sixteen men with AAAs (age 73 y ± 7) were imaged with contrast-enhanced magnetic resonance angiography during inspiratory and expiratory breath-holds. Centerline paths of the aorta and visceral arteries were acquired by geometric modeling and segmentation techniques. Vessel translations and changes in branching angle and curvature resulting from respiration were computed from centerline paths. RESULTS With expiration, the SMA, LRA, and RRA bifurcation points translated superiorly by 12.4 mm ± 9.5, 14.5 mm ± 8.8, and 12.7 mm ± 6.4 (P < .001), and posteriorly by 2.2 mm ± 2.7, 4.9 mm ± 4.2, and 5.6 mm ± 3.9 (P < .05), respectively, and the SMA translated rightward by 3.9 mm ± 4.9 (P < .01). With expiration, the SMA, LRA, and RRA angled upward by 9.7° ± 6.4, 7.5° ± 7.8, and 4.9° ± 5.3, respectively (P < .005). With expiration, mean curvature increased by 0.02 mm(-1) ± 0.01, 0.01 mm(-1) ± 0.01, and 0.01 mm(-1) ± 0.01 in the SMA, LRA, and RRA, respectively (P < .05). For inspiration and expiration, RRA curvature was greater than in other vessels (P < .025). CONCLUSIONS With expiration, the SMA, LRA, and RRA translated superiorly and posteriorly as a result of diaphragmatic motion, inducing upward angling of vessel branches and increased curvature. In addition, the SMA exhibited rightward translation with expiration. The RRA was significantly more tortuous, but deformed less than the other vessels during respiration.
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Affiliation(s)
- Ga-Young Suh
- Department of Surgery, Stanford University, Stanford, California 94305-5642, USA.
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Suh GY, Choi G, Draney MT, Herfkens RJ, Dalman RL, Cheng CP. Respiratory-induced 3D deformations of the renal arteries quantified with geometric modeling during inspiration and expiration breath-holds of magnetic resonance angiography. J Magn Reson Imaging 2013; 38:1325-32. [PMID: 23553967 DOI: 10.1002/jmri.24101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 02/06/2013] [Indexed: 11/12/2022] Open
Abstract
PURPOSE To quantify renal artery deformation due to respiration using magnetic resonance (MR) image-based geometric analysis. MATERIALS AND METHODS Five males were imaged with contrast-enhanced MR angiography during inspiratory and expiratory breath-holds. From 3D models of the abdominal aorta, left and right renal arteries (LRA and RRA), we quantified branching angle, curvature, peak curve angle, axial length, and locations of branch points. RESULTS With expiration, maximum curvature changes were 0.054 ± 0.025 mm(-1) (P < 0.01), and curve angle at the most proximal curvature peak increased by 8.0 ± 4.5° (P < 0.05) in the LRA. Changes in maximum curvature and curve angles were not significant in the RRA. The first renal bifurcation point translated superiorly and posteriorly by 9.7 ± 3.6 mm (P < 0.005) and 3.5 ± 2.1 mm (P < 0.05), respectively, in the LRA, and 10.8 ± 6.1 mm (P < 0.05) and 3.6 ± 2.5 mm (P < 0.05), respectively, in the RRA. Changes in branching angle, axial length, and renal ostia locations were not significant. CONCLUSION The LRA and RRA deformed and translated significantly. Greater deformation of the LRA as compared to the RRA may be due to asymmetric anatomy and mechanical support by the inferior vena cava. The presented methodology can extend to quantification of deformation of diseased and stented arteries to help renal artery implant development.
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Affiliation(s)
- Ga-Young Suh
- Department of Surgery, Stanford University, Stanford, California, USA
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10
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Worters PW, Saranathan M, Xu A, Vasanawala SS. Inversion-recovery-prepared dixon bSSFP: initial clinical experience with a novel pulse sequence for renal MRA within a breathhold. J Magn Reson Imaging 2012; 35:875-81. [PMID: 22095672 PMCID: PMC3290713 DOI: 10.1002/jmri.23503] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 10/20/2011] [Indexed: 11/10/2022] Open
Abstract
PURPOSE To evaluate the capability of a new breathhold non-contrast-enhanced MRA method (Non-contrast Outer Radial Inner Square k-space Scheme, NORISKS) to visualize renal arteries by comparing the method with a routine clinical but significantly longer non-contrast-enhanced (non-CE) MRA technique. MATERIALS AND METHODS Eighteen subjects referred for abdominal MRI were examined with NORISKS and a routine non-contrast-enhanced MRA technique. Two versions of NORISKS were evaluated: with and without ECG gating. The images were then scored independently and in blinded manner by two radiologists on 5-point scales for visualization of the proximal and distal renal arteries and quality of fat suppression. RESULTS No statistically significant difference was detected between NORISKS and routine clinical non-CE MRA in all categories except for visualization of the distal renal arteries where ungated NORISKS performed poorer than the routine non-CE MRA (P < 10(-4) ). CONCLUSION We have demonstrated a promising non-CE MRA method for acquiring renal angiograms within a breathhold without any compromise in spatial resolution or coverage. ECG-gated NORISKS is able to acquire renal angiograms that are comparable to a routine clinical non-CE MRA method (Inhance IFIR, GE Healthcare), which requires approximately seven times the scan time of NORISKS.
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Affiliation(s)
- Pauline W Worters
- Department of Radiology, Stanford University, Stanford, California, USA.
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Xu JL, Shi DP, Li YL, Zhang JL, Zhu SC, Shen H. Non-enhanced MR angiography of renal artery using inflow-sensitive inversion recovery pulse sequence: A prospective comparison with enhanced CT angiography. Eur J Radiol 2011; 80:e57-63. [DOI: 10.1016/j.ejrad.2010.08.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2010] [Revised: 07/27/2010] [Accepted: 08/02/2010] [Indexed: 10/19/2022]
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Oshin OA, How TV, Brennan JA, Fisher RK, McWilliams RG, Vallabhaneni SR. Magnitude of the Forces Acting on Target Vessel Stents as a Result of a Mismatch Between Native Aortic Anatomy and Fenestrated Stent-Grafts. J Endovasc Ther 2011; 18:569-75. [DOI: 10.1583/11-3471.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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13
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Khoo MMY, Deeab D, Gedroyc WMW, Duncan N, Taube D, Dick EA. Renal artery stenosis: comparative assessment by unenhanced renal artery mra versus contrast-enhanced MRA. Eur Radiol 2011; 21:1470-6. [DOI: 10.1007/s00330-011-2086-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 12/01/2010] [Accepted: 01/03/2011] [Indexed: 11/30/2022]
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14
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Binser T, Thoeny HC, Eisenberger U, Stemmer A, Boesch C, Vermathen P. Comparison of physiological triggering schemes for diffusion-weighted magnetic resonance imaging in kidneys. J Magn Reson Imaging 2010; 31:1144-50. [DOI: 10.1002/jmri.22156] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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Muthupillai R, Douglas E, Huber S, Lambert B, Pereyra M, Wilson GJ, Flamm SD. Direct comparison of sensitivity encoding (SENSE) accelerated and conventional 3D contrast enhanced magnetic resonance angiography (CE-MRA) of renal arteries: effect of increasing spatial resolution. J Magn Reson Imaging 2010; 31:149-59. [PMID: 20027583 DOI: 10.1002/jmri.22002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
PURPOSE To assess the effect of attaining higher spatial resolution in contrast-enhanced magnetic resonance angiography (MRA) of renal arteries using parallel imaging, sensitivity encoding (SENSE), by comparing the SENSE contrast-enhanced (CE) MRA against a conventional CE-MRA protocol with identical scan times, injection protocol, and other acquisition parameters. MATERIALS AND METHODS Numerical simulations and a direct comparison of SENSE-accelerated versus conventional acquisitions were performed. A total of 41 patients (18 male) were imaged using both protocols for a direct comparison. Both protocols used fluoroscopic triggering, centric encoding, breath-holding, equivalent injection protocol, and lasted approximately 30 seconds. RESULTS Simulated point-spread functions were narrower for the SENSE protocol compared to the conventional protocol. In the patient study, although the SENSE protocol produced images with lower signal-to-noise ratio (SNR), image quality was better for all segments of the renal arteries. In addition, ringing of kidney parenchyma and renal artery blurring were significantly reduced in the SENSE protocol. Finally, reader confidence improved with the SENSE protocol. CONCLUSION Despite a reduction in SNR, the higher-resolution SENSE CE-MRA provided improved image quality, reduced artifacts, and increased reader confidence compared to the conventional protocol.
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Affiliation(s)
- R Muthupillai
- Department of Radiology, St. Luke's Episcopal Hospital, Houston, Texas, USA.
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Wilson GJ, Maki JH. Non-contrast-enhanced MR imaging of renal artery stenosis at 1.5 tesla. Magn Reson Imaging Clin N Am 2009; 17:13-27. [PMID: 19364597 DOI: 10.1016/j.mric.2009.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Balanced steady-state free precession (Bal-SSFP) techniques produce excellent anatomic images of renal arteries without the use of contrast agents and are relatively flow-insensitive. Electrocardiography (ECG)-triggered and non-ECG-triggered sequences have been shown to be quite sensitive for detection of regional arterial stenosis (RAS), and the already high specificity is likely to increase with further refinement of the techniques. Bal-SSFP sequences can be used as a screening tool or as an alternative to contrast-enhanced (CE) magnetic resonance angiography (MRA) when contrast agents are contraindicated. In addition to morphologic imaging of RAS, non-CE techniques can be used in functional assessment of hemodynamic significance. The complimentary tools can be used alone or in combination with CE-MRA for MR imaging of renal vascular hypertension.
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Affiliation(s)
- Gregory J Wilson
- Department of Radiology (AA010-J), University of Washington, 1959 NE Pacific Street, Seattle, WA 98195, USA; Philips Healthcare, Cleveland, OH, USA.
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17
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Jin N, Lewandowski RJ, Omary RA, Larson AC. Respiratory self-gating for free-breathing abdominal phase-contrast blood flow measurements. J Magn Reson Imaging 2009; 29:860-8. [PMID: 19306414 DOI: 10.1002/jmri.21711] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PURPOSE To demonstrate the feasibility of using a free-breathing (FB) respiratory self-gated (RSG) approach for abdominal phase-contrast (PC) blood flow measurements. MATERIALS AND METHODS PC-magnetic resonance imaging (MRI) flow measurements were performed within the right renal artery, common hepatic artery, and main portal vein during breath-hold (BH) and FB with both signal averaging and RSG in eight healthy volunteers. The resultant images were qualitatively scored by two independent reviewers blinded to acquisition techniques. Blood flow volume and cross-sectional vessel size measurements were compared for three techniques. RESULTS The overall efficiency for the RSG-PC sequence was 38.9% +/- 4.7%. Images acquired with RSG effectively mitigated respiratory motion artifacts, which were clearly evident within FB signal-averaged images. RSG produced similar image quality to that of BH techniques (P > 0.146) and resulted in similar vessel size measurements (P = 0.694). Flow results for both FB RSG and signal-averaged reconstructions correlated well with BH flow measurements (r = 0.97 and 0.92, P < 0.001). However, only the RSG methods demonstrated excellent absolute agreement with BH-PC flow measurements (P = 0.600), with signal-averaged methods resulting in significant overestimations. CONCLUSION RSG methods can limit respiratory motion artifacts to reduce flow measurement inaccuracies during free-breathing PC measurements in the abdomen.
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Affiliation(s)
- Ning Jin
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, USA
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18
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Correlación arteriográfica en 30 pacientes con patología vascular renal diagnosticada mediante TC multicorte. RADIOLOGIA 2008; 50:393-400. [DOI: 10.1016/s0033-8338(08)76054-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Guzman R, Lovblad KO, Altrichter S, Remonda L, de Koning P, Andres RH, El-Koussy M, Kelly ME, Reiber JHC, Schroth G, Oswald H, Barth A. Clinical validation of an automated vessel-segmentation software of the extracranial-carotid arteries based on 3D-MRA: a prospective study. J Neuroradiol 2008; 35:278-85. [PMID: 18707758 DOI: 10.1016/j.neurad.2008.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVES To determine the accuracy of automated vessel-segmentation software for vessel-diameter measurements based on three-dimensional contrast-enhanced magnetic resonance angiography (3D-MRA). METHOD In 10 patients with high-grade carotid stenosis, automated measurements of both carotid arteries were obtained with 3D-MRA by two independent investigators and compared with manual measurements obtained by digital subtraction angiography (DSA) and 2D maximum-intensity projection (2D-MIP) based on MRA and duplex ultrasonography (US). In 42 patients undergoing carotid endarterectomy (CEA), intraoperative measurements (IOP) were compared with postoperative 3D-MRA and US. RESULTS Mean interoperator variability was 8% for measurements by DSA and 11% by 2D-MIP, but there was no interoperator variability with the automated 3D-MRA analysis. Good correlations were found between DSA (standard of reference), manual 2D-MIP (rP=0.6) and automated 3D-MRA (rP=0.8). Excellent correlations were found between IOP, 3D-MRA (rP=0.93) and US (rP=0.83). CONCLUSION Automated 3D-MRA-based vessel segmentation and quantification result in accurate measurements of extracerebral-vessel dimensions.
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Affiliation(s)
- R Guzman
- Department of Neurosurgery, Inselspital, Bern, Switzerland
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Muhs BE, Vincken KL, Teutelink A, Verhoeven ELG, Prokop M, Moll FL, Verhagen HJM. Dynamic Cine-Computed Tomography Angiography Imaging of Standard and Fenestrated Endografts: Differing Effects on Renal Artery Motion. Vasc Endovascular Surg 2008; 42:25-31. [DOI: 10.1177/1538574407308200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Different endograft configurations (fenestrated, transrenal, infrarenal) may varyingly affect aortic side branch movement. Renal artery motion was evaluated with 64-slice dynamic cine-computed tomography angiography before and after endovascular aneurysm repair in 16 patients (46 renal arteries). Center-of-mass displacement of the renals was determined per heartbeat for before repair for 3 different endografts; differences were compared, with significance at P < 0.5. Preoperative renal artery motion is significant (1.2 [SD 0.5] mm, range, 0.6-2.). Neither transrenal nor infrarenal endografts alter renal artery motion compared with before repair ( P < .05). Renal artery motion after fenestrated endovascular repair with renal stents reduces motion to 25% of the preoperative value (0.3 [SD, 0.1] mm, range, 0.2-0.5 mm; P = .01). Endograft implantation without stented side branches does not change renal artery motion, potentially allowing significant movement of the renal artery relative to the fenestration. Routine stenting of fenestrations limits postoperative renal artery motion to 0.3 mm, thereby preventing significant branch movement in relation the fenestration.
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Affiliation(s)
- Bart E. Muhs
- Department of Vascular Surgery University Medical Center Utrecht, Division of Vascular Surgery Yale University School of Medicine, New Haven, Connecticut
| | - Koen L. Vincken
- Department of Image Science Institute University Medical Center Utrecht
| | - Arno Teutelink
- Department of Vascular Surgery University Medical Center Utrecht
| | | | | | - Frans L. Moll
- Department of Vascular Surgery University Medical Center Utrecht
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21
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Laskowski I, Verhagen HJM, Gagne PJ, Moll FL, Muhs BE. Current state of dynamic imaging in endovascular aortic aneurysm repair. J Endovasc Ther 2008; 14:807-12. [PMID: 18052589 DOI: 10.1583/07-2116.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Dynamic imaging, in which the time dimension has a specific function in data (image) interpretation, is becoming increasingly important when contemplating endovascular aneurysm repair. Clinical parameters and complications, including proper sizing, successful aneurysm sac exclusion, optimal stent-graft design, endoleaks, graft migration, and stent fracture are beginning to be better understood through dynamic magnetic resonance, ultrasound, and dynamic computed tomography. The current practice using static 3-dimensional reconstructions for the planning and follow-up of aortic aneurysm endograft treatment will most likely evolve, and the use of dynamic aortic imaging will continue to increase. Validation of these imaging modalities in larger scale trials is needed.
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Affiliation(s)
- Igor Laskowski
- Division of Vascular Surgery, New York University School of Medicine, New York, NY, USA
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22
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Kramer U, Wiskirchen J, Fenchel MC, Seeger A, Laub G, Tepe G, Finn JP, Claussen CD, Miller S. Isotropic high-spatial-resolution contrast-enhanced 3.0-T MR angiography in patients suspected of having renal artery stenosis. Radiology 2008; 247:228-40. [PMID: 18270376 DOI: 10.1148/radiol.2471070565] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The purpose of this study was to prospectively evaluate the diagnostic performance of contrast material-enhanced magnetic resonance (MR) angiography performed at 3 T for assessment of renal artery stenosis (RAS) by using parallel acquisition techniques with high acceleration factors and with digital subtraction angiography (DSA) as the reference standard. The study was institutional review board approved, and written informed consent was obtained from all patients. Twenty-nine patients (18 men, 11 women; mean age, 57.1 years +/- 14.3 [standard deviation]) suspected of having RAS underwent MR angiography. Images were evaluated qualitatively and quantitatively. The interobserver variability, sensitivity, specificity, and positive and negative predictive values of 3-T MR angiography, as compared with DSA (performed in 15 patients), were calculated. All examinations yielded good or excellent image quality. The sensitivity and specificity of MR angiography in grading significant (>75%) stenosis were 94% and 96%, respectively. Owing to its high sensitivity, contrast-enhanced 3-T MR angiography can be used reliably to exclude RAS and can serve as a useful screening method in the diagnostic work-up of patients with arterial hypertension.
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Affiliation(s)
- Ulrich Kramer
- Department of Diagnostic Radiology, University of Tuebingen, Hoppe-Seyler-Str 3, 72076 Tuebingen, Germany.
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23
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Wyttenbach R, Braghetti A, Wyss M, Alerci M, Briner L, Santini P, Cozzi L, Di Valentino M, Katoh M, Marone C, Vock P, Gallino A. Renal Artery Assessment with Nonenhanced Steady-State Free Precession versus Contrast-enhanced MR Angiography. Radiology 2007; 245:186-95. [PMID: 17717326 DOI: 10.1148/radiol.2443061769] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To prospectively assess the diagnostic accuracy of nonenhanced three-dimensional (3D) steady-state free precession (SSFP) magnetic resonance (MR) angiography for detection of renal artery stenosis (RAS), with breath-hold contrast material-enhanced MR angiography performed as the reference standard. MATERIALS AND METHODS The study was local ethics committee approved; all patients gave written informed consent. Fifty-three patients (30 male, 23 female; mean age, 58 years) with arterial hypertension and suspected of having RAS were examined with 1.5-T 3D SSFP renal MR angiography. Stenosis grade, maximal visible vessel length, and subjective image quality were compared. Sensitivity, specificity, accuracy, and negative predictive value (NPV) were calculated on artery-by-artery and patient-by-patient bases. The significance of the results was assessed with the paired two-sided t test for continuous variables and with the marginal homogeneity test for categorical variables. Cohen kappa statistics were used to estimate interobserver agreement. RESULTS One hundred eight renal arteries with 20 significant (>or=50%) stenoses were detected with contrast-enhanced MR angiography. At artery-by-artery analysis, sensitivity, specificity, accuracy, and NPV of nonenhanced SSFP MR angiography for RAS detection were 100%, 93%, 94%, and 100%, respectively, for observer 1 and 95%, 95%, 95%, and 99%, respectively, for observer 2. Corresponding patient-by-patient values were 100%, 92%, 94%, and 100%, respectively, for observer 1 and 100%, 95%, 96%, and 100%, respectively, for observer 2. Overestimation of stenosis grade with SSFP MR angiography resulted in six and four false-positive findings for readers 1 and 2, respectively. Mean maximal visible lengths of the renal arteries were 69.9 mm at contrast-enhanced MR angiography and 61.1 mm at SSFP MR angiography (P<.001). Both techniques yielded good to excellent image quality. CONCLUSION Slab-selective inversion-prepared 3D SSFP MR angiography had high sensitivity, specificity, accuracy, and NPV for RAS detection, without the need for contrast material. However, RAS severity was overestimated in some patients.
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Affiliation(s)
- Rolf Wyttenbach
- Department of Radiology, Ospedale San Giovanni Bellinzona, CH-6500 Bellinzona, Switzerland, and Department of Radiology, University of Aachen, Aachen, Germany.
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24
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Wilson GJ, Eubank WB, Vasbinder GBC, Kessels AGH, Hoogeveen RM, Muthupillai R, Maki JH. Utilizing SENSE to reduce scan duration in high-resolution contrast-enhanced renal MR angiography. J Magn Reson Imaging 2006; 24:873-9. [PMID: 16941607 DOI: 10.1002/jmri.20691] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To evaluate the use of sensitivity encoding (SENSE) to reduce scan time and decrease detrimental artifacts arising from motion and bolus profile effects during contrast-enhanced MR angiography (CE-MRA) of the renal arteries (RAs). MATERIALS AND METHODS A direct comparison of conventional and SENSE (acceleration factor 2) CE-MRA protocols was performed on 20 patients. Each patient underwent both scans. Both protocols achieved the same resolution, but the SENSE protocol was 50% faster and utilized a faster injection than the conventional scan. Three radiologists graded the images for image quality, artifact levels, and reader confidence. RESULTS While the signal-to-noise ratio (SNR) decreased (26+/-5 vs. 30+/-10; P=0.04) with the SENSE protocol, the image-quality scores for four identified segments of the RAs increased or were unchanged. The largest improvements in image quality occurred in the more distal segments of the RAs. Parenchymal ringing (P=0.005) and RA blurring (P=0.006) were significantly reduced, and there was a trend toward improvement of RA ringing despite the increased injection rate. CONCLUSION The faster SENSE scan maintained nearly the same SNR (due to faster injection of Gd-chelate), reduced artifact levels, and improved image quality ratings for the distal renal vessels.
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Affiliation(s)
- Gregory J Wilson
- Department of Radiology, Puget Sound VA Health Care System, Seattle, University of Washington 98109, USA, and Maastricht University Hospital, The Netherlands.
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Muhs BE, Teutelink A, Prokop M, Vincken KL, Moll FL, Verhagen HJM. Endovascular Aneurysm Repair Alters Renal Artery Movement: A Preliminary Evaluation Using Dynamic CTA. J Endovasc Ther 2006; 13:476-80. [PMID: 16928161 DOI: 10.1583/05-1794mr.1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
PURPOSE To observe the natural renal artery motion during cardiac cycles in patients with abdominal aortic aneurysm (AAA) and how the implantation of stent-grafts may distort this movement. METHODS Data on 29 renal arteries from 15 male patients (mean age 72.6 years, range 66-83) treated with Talent or Excluder stent-grafts were acquired using an electrocardiographically (ECG)-gated dynamic 64-slice CT scanner. ECG-triggered retrospective reconstructions were made at 8 equidistant time points over the R-R cardiac cycle. The gated datasets were reconstructed perpendicular to the center flow lumen of each renal artery at 1.2 and 2.4 cm from the renal ostium. Center of mass displacement was determined per cardiac cycle for pre- and post-EVAR renal arteries and compared. RESULTS Normal renal artery motion in AAA patients was impressive, with up to 3-mm movement both near and distant from the aorta (mean 2.0+/-0.6 mm, range 1.1-3.0). EVAR inhibited proximal renal motion, resulting in a 31% decrease in maximal movement (mean 1.4+/-0.7 mm, range 0.7-2.0; p < or = 0.05). Distal renal artery motion was unaffected by EVAR, with motion similar to the pre-EVAR state. CONCLUSION ECG-gated dynamic CTA is feasible on a 64-slice scanner with a standard radiation dose and can detect potentially serious consequences of EVAR. EVAR alters renal artery motion by limiting proximal motion while leaving distal motion unaffected.
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Affiliation(s)
- Bart E Muhs
- Department of Vascular Surgery, University Medical Center, Utrecht, The Netherlands
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26
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Bax L, Bakker CJG, Klein WM, Blanken N, Beutler JJ, Mali WPTRM. Renal blood flow measurements with use of phase-contrast magnetic resonance imaging: normal values and reproducibility. J Vasc Interv Radiol 2005; 16:807-14. [PMID: 15947044 DOI: 10.1097/01.rvi.0000161144.98350.28] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To assess the validity and the direct, short-term, and long-term reproducibility of renal blood flow (RBF) measurements with phase-contrast (PC) magnetic resonance (MR) imaging. MATERIALS AND METHODS In 20 healthy volunteers, RBF measurements were repeated with and without repositioning. Internal validity was assessed by comparing the total RBF with the difference in aortic flow above and below the renal arteries. In 19 healthy volunteers, RBF measurements were performed at two different occasions. In 40 healthy volunteers, RBF measurements were performed to assess normal values as a function of age. Analyses were performed according to Bland and Altman. RESULTS The technical success rate ranged from 78% to 85%. Total RBF and the difference in aortic flow rates showed good agreement (Pearson correlation coefficient, 0.72; P = .002). Directly repeated measurements had a mean difference of 54 mL/min in total RBF with a coefficient of variation (CV) of 17%. For repeated measurements with repositioning, the mean difference in total RBF was 74 mL/min (CV, 23%). Repeated measurements on different occasions showed a CV of 20%. The mean total RBF of the 40 healthy volunteers was 838 mL/min +/- 244 (SD). CONCLUSIONS RBF measurement with PC MR has a success rate greater than 75%. The demonstrated internal reliability of this method and fair reproducibility of the flow parameters is crucial for further studies of the renal artery with MR imaging.
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Affiliation(s)
- Liesbeth Bax
- Department of Radiology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands.
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Katoh M, Spuentrup E, Stuber M, Hoogeveen R, Günther RW, Buecker A. Free-breathing renal magnetic resonance angiography with steady-state free-precession and slab-selective spin inversion combined with radialk-space sampling and water-selective excitation. Magn Reson Med 2005; 53:1228-33. [PMID: 15844141 DOI: 10.1002/mrm.20467] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The impact of radial k-space sampling and water-selective excitation on a novel navigator-gated cardiac-triggered slab-selective inversion prepared 3D steady-state free-precession (SSFP) renal MR angiography (MRA) sequence was investigated. Renal MRA was performed on a 1.5-T MR system using three inversion prepared SSFP approaches: Cartesian (TR/TE: 5.7/2.8 ms, FA: 85 degrees), radial (TR/TE: 5.5/2.7 ms, FA: 85 degrees) SSFP, and radial SSFP combined with water-selective excitation (TR/TE: 9.9/4.9 ms, FA: 85 degrees). Radial data acquisition lead to significantly reduced motion artifacts (P < 0.05). SNR and CNR were best using Cartesian SSFP (P < 0.05). Vessel sharpness and vessel length were comparable in all sequences. The addition of a water-selective excitation could not improve image quality. In conclusion, radial k-space sampling reduces motion artifacts significantly in slab-selective inversion prepared renal MRA, while SNR and CNR are decreased. The addition of water-selective excitation could not improve the lower CNR in radial scanning.
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Affiliation(s)
- Marcus Katoh
- Department of Diagnostic Radiology, University Hospital Aachen, University of Technology (RWTH), Germany.
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28
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Katoh M, Buecker A, Stuber M, Günther RW, Spuentrup E. Free-breathing renal MR angiography with steady-state free-precession (SSFP) and slab-selective spin inversion: Initial results. Kidney Int 2004; 66:1272-8. [PMID: 15327427 DOI: 10.1111/j.1523-1755.2004.00882.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The aim of our study was the investigation of a novel navigator-gated three-dimensional (3D) steady-state free-precession (SSFP) sequence for free-breathing renal magnetic resonance angiography (MRA) without contrast medium, and to examine the advantage of an additional inversion prepulse for improved contrast. METHODS Eight healthy volunteers (mean age 29 years) and eight patients (mean age 53 years) were investigated on a 1.5 Tesla MR system (ACS-NT, Philips, Best, The Netherlands). Renal MRA was performed using three navigator-gated free-breathing cardiac-triggered 3D SSFP sequences [repetition time (TR) = 4.4 ms, echo time (TE) = 2.2 ms, flip angle 85 degrees, spatial resolution 1.25 x 1.25 x 4.0 mm(3), scanning time approximately 1 minute 30 seconds]. The same sequence was performed without magnetization preparation, with a non-slab selective and a slab-selective inversion prepulse. Signal-to-noise ratio (SNR), contrast-to-noise (CNR) vessel length, and subjective image quality were compared. RESULTS Three-dimensional SSFP imaging combined with a slab-selective inversion prepulse enabled selective and high contrast visualization of the renal arteries, including the more distal branches. Standard SSFP imaging without magnetization preparation demonstrated overlay by veins and renal parenchyma. A non-slab-selective prepulse abolished vessel visualization. CNR in SSFP with slab-selective inversion was 43.6 versus 10.6 (SSFP without magnetization preparation) and 0.4 (SSFP with non-slab-selective inversion), P < 0.008. CONCLUSION Navigator-gated free-breathing cardiac-triggered 3D SSFP imaging combined with a slab-selective inversion prepulse is a novel, fast renal MRA technique without the need for contrast media.
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Affiliation(s)
- Marcus Katoh
- Department of Diagnostic Radiology, University Hospital, University of Technology, Aachen, Germany.
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Wilson GJ, Hoogeveen RM, Willinek WA, Muthupillai R, Maki JH. Parallel Imaging in MR Angiography. Top Magn Reson Imaging 2004; 15:169-85. [PMID: 15479999 DOI: 10.1097/01.rmr.0000134199.94874.70] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The recently developed techniques of parallel imaging with phased array coils are rapidly becoming accepted for magnetic resonance angiography (MRA) applications. This article reviews the various current parallel imaging techniques and their application to MRA. The increased scan efficiency provided by parallel imaging allows increased temporal or spatial resolution, and reduction of artifacts in contrast-enhanced MRA (CE-MRA). Increased temporal resolution in CE-MRA can be used to reduce the need for bolus timing and to provide hemodynamic information helpful for diagnosis. In addition, increased spatial resolution (or volume coverage) can be acquired in a breathhold (eg, in renal CE-MRA), or in otherwise limited clinically acceptable scan durations. The increased scan efficiency provided by parallel imaging has been successfully applied to CE-MRA as well as other MRA techniques such as inflow and phase contrast imaging. The large signal-to-noise ratio available in many MRA techniques lends these acquisitions to increased scan efficiency through parallel imaging.
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de Koning PJH, Schaap JA, Janssen JP, Westenberg JJM, van der Geest RJ, Reiber JHC. Automated segmentation and analysis of vascular structures in magnetic resonance angiographic images. Magn Reson Med 2003; 50:1189-98. [PMID: 14648566 DOI: 10.1002/mrm.10617] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The accurate assessment of the presence and extent of vascular disease, and planning of vascular interventions based on MRA requires the determination of vessel dimensions. The current standard is based on measuring vessel diameters on maximum intensity projections (MIPs) using calipers. In order to increase the accuracy and reproducibility of the method, automated analysis of the 3D MR data is required. A novel method for automatically determining the trajectory of the vessel of interest, the luminal boundaries, and subsequent the vessel dimensions is presented. The automated segmentation in 3D uses deformable models, combined with knowledge of the acquisition protocol. The trajectory determination was tested on 20 in vivo studies of the abdomen and legs. In 93% the detected trajectory followed the vessel. The luminal boundary detection was validated on contrast-enhanced (CE) MRA images of five stenotic phantoms. The results from the automated analysis correlated very well with the true diameters of the phantoms used in the in vitro study (r = 0.999, P < 0.001). MRA and x-ray angiography (XA) of the phantoms also correlated well (r = 0.895, P < 0.001). The average unsigned difference between the MRA and XA measurements was 0.08 +/- 0.05 mm. In conclusion, the automated approach allows the accurate assessment of vessel dimensions in MRA images.
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Affiliation(s)
- P J H de Koning
- Division of Image Processing, Department of Radiology, Leiden University Medical Center, Leiden, The Netherlands.
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Vasbinder GBC, Maki JH, Nijenhuis RJ, Leiner T, Wilson GJ, Kessels AGH, Lemaire EELE, Kaandorp DW, Ho KYJAM, van Engelshoven JMA, Lemarie EELE. Motion of the distal renal artery during three-dimensional contrast-enhanced breath-hold MRA. J Magn Reson Imaging 2002; 16:685-96. [PMID: 12451582 DOI: 10.1002/jmri.10214] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE To study the potential detrimental effects of renal motion on breath-hold three-dimensional contrast-enhanced (CE) magnetic resonance angiography (MRA). MATERIALS AND METHODS A computer model simulating linear motion was applied to MRA pulse sequences. Subsequently, to study whether renal motion was present, 24 patients being evaluated for possible renovascular hypertension underwent a breath-hold nonenhanced single slice two-dimensional dynamic turbo field-echo magnetic resonance imaging (MRI) scan with a typical duration of 32 seconds. This sequence was followed by breath-hold three-dimensional CE renal MRA. CE-MRA images were evaluated by two independent observers. RESULTS The computer model revealed linear renal motion to cause artifacts. The severity of these artifacts correlated with velocity. Significant (P < 0.001) near linear cranial motion of the kidneys and diaphragm during a sustained breath-hold was found for the right kidney, left kidney, right diaphragm, and left diaphragm (0.26 +/- 0.21 mm/second, 0.25 +/- 0.23 mm/second, 0.43 +/- 0.43 mm/second, and 0.29 +/- 0.33 mm/second [mean +/- SD], respectively). CE-MRA images showed artifacts of the distal renal artery that corroborated the computer model findings. CONCLUSION The observed cranial motion of the kidneys during a breath-hold adversely affects distal renal artery image quality on three-dimensional CE-MRA and jeopardizes reliable clinical evaluation. Shortening scan time may be beneficial for decreasing image degradation caused by this phenomenon.
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Spuentrup E, Buecker A, Meyer J, Günther RW, Stuber M. Navigator-gated free-breathing 3D balanced FFE projection renal MRA: Comparison with contrast-enhanced breath-hold 3D MRA in a swine model. Magn Reson Med 2002; 48:739-43. [PMID: 12353294 DOI: 10.1002/mrm.10271] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A cardiac-triggered, free-breathing, 3D balanced FFE projection renal MR angiography (MRA) technique with a 2D pencil beam aortic labeling pulse for selective aortic spin tagging was developed. For respiratory motion artifact suppression during free breathing, a prospective real-time navigator was implemented for renal MRA. Images obtained with the new approach were compared with standard contrast-enhanced (CE) 3D breath-hold MRA in seven swine. Signal properties and vessel visualization were analyzed. With the presented technique, high-resolution, high-contrast renal projection MRA with superior vessel length visualization (including a greater visible number of distal branches of the renal arteries) compared to standard breath-hold CE-MRA was obtained. The present results warrant clinical studies in patients with renal artery disease.
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Affiliation(s)
- Elmar Spuentrup
- Department of Diagnostic Radiology, Technical University of Aachen, Germany.
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Current awareness. NMR IN BIOMEDICINE 2002; 15:75-86. [PMID: 11840556 DOI: 10.1002/nbm.746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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