Publications
411 results found
Johansson B, Babu-Narayan SV, Kilner PJ, et al., 2010, 3-dimensional time-resolved contrast-enhanced magnetic resonance angiography for evaluation late after the Mustard operation for transposition, CARDIOLOGY IN THE YOUNG, Vol: 20, Pages: 1-7, ISSN: 1047-9511
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- Citations: 5
Johansson B, Babu-Narayan SV, Kilner PJ, et al., 2010, 3-dimensional time-resolved contrast-enhanced magnetic resonance angiography for evaluation late after the mustard operation for transposition., Cardiol Young, Vol: 20, Pages: 1-7
PURPOSE: Cardiovascular magnetic resonance assessment of adults late after an atrial redirection operation for transposition is demanding and time consuming. We hypothesised that the relatively fast and standardised 3-dimensional time-resolved contrast-enhanced magnetic resonance angiography, or dynamic angiography, would be valuable in the periodic follow-up of these patients. METHODS: We investigated prospectively 36 adults with transposition using dynamic angiography, comparing our results against a comprehensive but non-contrast cardiovascular magnetic resonance protocol. We acquired 6 dynamic angiographic datasets after injection of contrast. The primary aim was to detect significant obstruction of the pathways for venous flow. RESULTS: In 4 patients (11%), we found evidence of moderate-to-severe, and thus clinically important, obstruction of systemic venous channels on standard cardiovascular magnetic resonance. All these patients were correctly identified by dynamic angiography. In 4 additional patients, we found mild and haemodynamically insignificant obstructions in the systemic venous channels. Of the 8 (22%) patients with any obstruction, 6 were detected by angiography. There were no false positives reported, giving sensitivity of 75% and specificity of 100%, a positive predictive value of 100%, and negative predictive value of 93%. In 1 patient, there was a moderate obstruction of the pulmonary venous compartment which was not readily seen by dynamic angiography. CONCLUSIONS: 3-dimensional dynamic angiography is a useful method for detecting anatomically moderate-to-severe, but not mild, obstructions in the systemic venous channels following Mustard repair for transposition. This technique can be used as a single imaging method and/or as complimentary to standard two dimensional cardiovascular magnetic resonance techniques for detection of clinically important obstructions in the systemic venous channels.
Wilkins MR, Ali O, Bradlow W, et al., 2010, Simvastatin as a Treatment for Pulmonary Hypertension Trial (SiPHT)., Am J Respir Crit Care Med
RATIONALE: In animal models of pulmonary hypertension, simvastatin has been shown to reduce pulmonary artery pressure and induce regression of associated right ventricular (RV) hypertrophy. OBJECTIVES: To assess the therapeutic value of simvastatin in patients with pulmonary arterial hypertension (PAH). METHODS: Forty-two patients with PAH were randomised to receive either simvastatin (80mg/day) or placebo in addition to current care for 6 months, and thereafter offered open-label simvastatin. The primary outcome was change in RV mass, assessed by cardiac magnetic resonance (CMR). MEASUREMENTS AND MAIN RESULTS: At 6 months, RV mass decreased by 5.2 +/- 11 g in the statin group (p=0.045) and increased 3.9 +/- 14 g in the placebo group. The treatment effect was -9.1 g (p=0.028). NT-proBNP levels fell significantly in the statin group (-75 +/- 167 fmol.ml(-1), p=0.02) but not the placebo group (49 +/- 224 fmol.ml(-1), p=0.43, overall treatment effect -124 fmol.ml(-1), p=0.041). There were no significant changes in other outcome measures (including 6 minute walk test, cardiac output and circulating cytokines). From 6 to 12 months, both RV mass and NT-proBNP increased towards baseline values in 16 patients on active treatment who continued with simvastatin but remained stable in 18 patients who switched from placebo to simvastatin. Two patients required a reduction in dose but not cessation of simvastatin. CONCLUSION: Simvastatin added to conventional therapy produces a small and transient early reduction in RV mass and NT-proBNP levels in PAH patients but this is not sustained over 12 months. Clinical Trials Registration Information: URL: http://www.clinicaltrials.gov Unique identifier: NCT00180713.
Bradlow WM, Hughes ML, Keenan NG, et al., 2010, Measuring the Heart in Pulmonary Arterial Hypertension (PAH): Implications for Trial Study Size, JOURNAL OF MAGNETIC RESONANCE IMAGING, Vol: 31, Pages: 117-124, ISSN: 1053-1807
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- Citations: 41
Perera R, Yadav R, Babu-Narayan S, et al., 2010, Pitfalls of Pectus Repair in Marfan Syndrome: a Case of Successful Re-operation on an Infected Ascending Aortic Graft in a Marfan Patient 20 Years After an Aortic Valve Sparing Root Replacement and Multiple Pectus Repair Operations, Publisher: AMER THORACIC SOC, ISSN: 1073-449X
Soloperto G, Keenan NG, Sheppard MN, et al., 2010, Combined imaging, computational and histological analysis of a ruptured carotid plaque: A patient-specific analysis., Artery Research, Vol: 4, Pages: 59-65
Background: Rupture of carotid plaques is an important cause of cerebrovascularevents. Several factors, including wall shear stress (WSS), plaque morphology and peak capstress, have been associated with plaque vulnerability. The aim of this study was to investigatethe relationship between these factors in an in vivo human ruptured carotid plaque.Methods: A 74-year-old male presenting with a transient ischemic attack underwent carotidmagnetic resonance imaging (MRI), which indicated a ruptured plaque, followed by carotidendarterectomy, from which plaque histology was assessed. The carotid bifurcation was reconstructedfrom the MRI data, and three-dimensional flow simulations were performed usingcomputational fluid dynamics to determine WSS and related parameters. Plaque vulnerabilitywas assessed using a biomechanical method based on modified Glagov criteria.Results: The plaque rupture was just distal to the site of maximum stenosis in a region of lowWSS, where MRI and histology both demonstrated fibrous cap thinning, a large lipid pool andcalcification in the shoulder region. Plaque vulnerability analysis indicated critically vulnerableplaque at the rupture site by a wide margin.Conclusions: Both low and high WSS have been associated with plaque vulnerability, and highmechanical stress in the cap has been linked to plaque rupture, but these parameters are notroutinely assessed clinically. This study demonstrates a complete analysis by combiningimaging, histology and bio-fluid and biomechanical modelling.
Soloperto G, Keenan N, Sheppard M, et al., 2009, A COMBINED IMAGING, COMPUTATIONAL AND HISTOLOGICAL ANALYSIS OF A RUPTURED CAROTID ARTERY, Spring Meeting of the British-Society-for-Cardiovascular-Research, Publisher: B M J PUBLISHING GROUP, ISSN: 1355-6037
Keenan NG, Sheppard MN, Nott DM, et al., 2009, Carotid plaque rupture, LANCET, Vol: 374, Pages: 1703-1703, ISSN: 0140-6736
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- Citations: 5
Asgar AW, Rana B, Rubens M, et al., 2009, Imaging options for the selection of anatomically suitable patients for transcatheter aortic valve implantation, EUROPEAN HEART JOURNAL, Vol: 30, Pages: 431-431, ISSN: 0195-668X
Chen SSM, Mohiaddin RH, 2009, Complications of aortic coarctation repair assessed using cardiovascular magnetic resonance, EUROPEAN HEART JOURNAL, Vol: 30, Pages: 314-315, ISSN: 0195-668X
Alpendurada F, Kiotsekoglou A, Wong J, et al., 2009, Marfan's cardiomyopathy: a novel entity from a well-known disease?, EUROPEAN HEART JOURNAL, Vol: 30, Pages: 547-548, ISSN: 0195-668X
Soloperto G, Keenan NG, Chan C, et al., 2009, Comparison between ruptured and intact atherosclerotic plaques: flow- modelling study of in vivo carotid arteries by cardiovascular magnetic resonance, EUROPEAN HEART JOURNAL, Vol: 30, Pages: 763-763, ISSN: 0195-668X
Deac MO, Sheppard MN, Moat N, et al., 2009, From Uterus to Pulmonary Embolus An Uncommon Association, CIRCULATION, Vol: 120, Pages: E16-E19, ISSN: 0009-7322
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- Citations: 6
Locca D, Hughes M, Mohiaddin R, 2009, Cardiovascular magnetic resonance diagnosis of a previously unreported association: Cor triatriatum with right partial anomalous pulmonary venous return to the azygos vein, INTERNATIONAL JOURNAL OF CARDIOLOGY, Vol: 135, Pages: E80-E82, ISSN: 0167-5273
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- Citations: 4
Karima R, Mohiaddin R, Rueckert D, 2009, Left atrium pulmonary veins: segmentation and quantification for planning atrial fibrillation ablation, ISSN: 1605-7422
The paper presents a technique for detecting detecting left atrium as well as the pulmonary veins of the left atrium by tracing out their centerlines. A vessel detection and traversal process is initiated from the venoatrial junctions. Pulmonary veins draining into the left atrium via these junctions are thus detected, also enabling the detection of the ostium. Ostial diameters are measured from the detected centerlines using a best-fitting ellipse. Quantitative validation of the techniques are reported on nine patient datasets. In only two of the datasets, mis-detections were identified. The ostial diameter measurements indicated an error of at most 5% in most of the cases. We envisage that the techniques presented will facilitate in planning the non-pharmacological treatment of atrial fibrillation using radio-frequency ablation therapy. © 2009 SPIE.
Treasure T, Gallivan S, Golesworthy T, et al., 2009, Unknown unknowns: the aorta through the looking glass, EUROPEAN JOURNAL OF CARDIO-THORACIC SURGERY, Vol: 35, Pages: 925-926, ISSN: 1010-7940
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- Citations: 4
He T, Smith GC, Gatehouse PD, et al., 2009, On Using <i>T</i><sub>2</sub> to Assess Extrinsic Magnetic Field Inhomogeneity Effects Myocardial Siderosis on <i>T</i><sub>2</sub>* Measurements in in Thalassemia, MAGNETIC RESONANCE IN MEDICINE, Vol: 61, Pages: 501-506, ISSN: 0740-3194
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- Citations: 19
Bradlow WM, Gatehouse PD, Hughes RL, et al., 2009, Transit-Time Method to Demonstrate Whether or Not an Impedance Matching Occurs at the Pulmonary Junction Response, JOURNAL OF MAGNETIC RESONANCE IMAGING, Vol: 29, Pages: 499-499, ISSN: 1053-1807
Kafka H, Mohiaddin RH, 2009, Cardiac MRI and Pulmonary MR Angiography of Sinus Venosus Defect and Partial Anomalous Pulmonary Venous Connection in Cause of Right Undiagnosed Ventricular Enlargement, AMERICAN JOURNAL OF ROENTGENOLOGY, Vol: 192, Pages: 259-266, ISSN: 0361-803X
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- Citations: 34
Tan FPP, Torii R, Borghi A, et al., 2009, Analysis of flow patterns in a patient-specific thoracic aortic aneurysm model, Publisher: Elsevier, Pages: 680-690
In this study, a newly developed two-equation transitional model was employed for the prediction of blood flow patterns in a thoracic aortic aneurysm (TAA) where the growth and progression are closely linked to low and oscillating wall shear stresses. Laminar–turbulent transition in the dilated vessel can alter the flow structure, shear stress and pressure distribution within the aneurysm. A patient-specific TAA model was reconstructed from magnetic-resonance (MR) images and measured velocity waveform was used as the inflow condition. Laminar flow and a correlation-based transitional version of Menter’s hybrid k /k x Shear Stress Transport (SST Tran) model were implemented in pulsatile simulations from which WSS distribution was obtained throughout a cardiac cycle and velocity profiles were compared with MR measurements. The correlation-based transitional model was found to produce results in closer agreement with the MR data than the laminar flow simulation.
Tan FPP, Torii R, Borghi A, et al., 2009, Fluid-structure interaction analysis of wall stress and flow patterns in a thoracic aortic aneurysm, International Journal of Applied Mechanics, Vol: 1, Pages: 179-199
In this study, fluid-structure interaction (FSI) simulation was carried out to predict wall shear stress (WSS) and blood flow patterns in a thoracic aortic aneurysm (TAA) where haemodynamic stresses on the diseased aortic wall are thought to lead to the growth, progression and rupture of the aneurysm. Based on MR images, a patient-specific TAA model was reconstructed. A newly developed two-equation laminar-turbulent transitional model was employed and realistic velocity and pressure waveforms were used as boundary conditions. Analysis of results include turbulence intensity, wall displacement, WSS, wall tensile stress and comparison of velocity profiles between MRI data, rigid and FSI simulations. Velocity profiles demonstrated that the FSI simulation gave better agreement with the MRI data while results for the time-averaged WSS (TAWSS) and oscillatory shear index (OSI) distributions showed no qualitative differences between the simulations. With the FSI model, the maximum TAWSS value was 13% lower, whereas the turbulence intensity was significantly higher than the rigid model. The FSI simulation also provided results for wall mechanical stress in terms of von Mises stress, allowing regions of high wall stress to be identified.
Soloperto G, Keenan N, Sheppard M, et al., 2009, PLAQUE RUPTURE IN THE CAROTID ARTERY: A COMBINED IMAGING, COMPUTATIONAL AND HISTOLOGICAL ANALYSIS, ASME Summer Bioengineering Conference, Publisher: AMER SOC MECHANICAL ENGINEERS, Pages: 1075-1076
Karim R, Rueckert D, Mohiaddin R, et al., 2009, AUTOMATIC EXTRACTION OF THE LEFT ATRIAL ANATOMY FROM MR FOR ATRIAL FIBRILLATION ABLATION, IEEE International Symposium on Biomedical Imaging - From Nano to Macro, Publisher: IEEE, Pages: 502-+, ISSN: 1945-7928
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- Citations: 1
Keenan NG, Pennell DJ, Mohiaddin RH, 2009, Glagov remodelling in the atherosclerotic carotid artery by cardiovascular magnetic resonance., BMJ Case Rep, Vol: 2009
Chan KM, Wage R, Symmonds K, et al., 2008, Towards comprehensive assessment of mitral regurgitation using cardiovascular magnetic resonance. Chan KM, Wage, J Cardiovasc Magn Reson., Vol: 22
He T, Gatehouse PD, Smith GC, et al., 2008, Myocardial T2* measurements in iron-overloaded thalassemia: An in vivo study to investigate optimal methods of quantification., Magn Reson Med, Vol: 60, Pages: 1082-1089, ISSN: 1522-2594
Reproducible and accurate myocardial T(2) (*) measurements are required for the quantification of iron in heart tissue in transfused thalassemia. The aim of this study was to determine the best method to measure the myocardial T(2) (*) from multi-gradient-echo data acquired both with and without black-blood preparation. Sixteen thalassemia patients from six centers were scanned twice locally, within 1 week, using an optimized bright-blood T(2) (*) sequence and then subsequently scanned at the standardization center in London within 4 weeks, using a T(2) (*) sequence both with and without black-blood preparation. Different curve-fitting models (monoexponential, truncation, and offset) were applied to the data and the results were compared by means of reproducibility. T(2) (*) measurements obtained using the bright- and black-blood techniques. The black-blood data were well fitted by the monoexponential model, which suggests that a more accurate measure of T(2) (*) can be obtained by removing the main source of errors in the bright-blood data. For bright-blood data, the offset model appeared to underestimate T(2) (*) values substantially and was less reproducible. The truncation model gave rise to more reproducible T(2) (*) measurements, which were also closer to the values obtained from the black-blood data. Magn Reson Med 60:1082-1089, 2008. (c) 2008 Wiley-Liss, Inc.
Wechalekar K, Chandrasekaran B, Stirrup J, et al., 2008, SPECT Radionuclide Ventriculography in the Assessment of Advanced Heart Failure Patients: A Comparison of Planar Radionuclide Ventriculography, Transthoracic Echocardiography and Cardiac Magnetic Resonance Imaging, EUROPEAN JOURNAL OF NUCLEAR MEDICINE AND MOLECULAR IMAGING, Vol: 35, Pages: S176-S177, ISSN: 1619-7070
Alpendurada F, Wage R, Mohiaddin R, 2008, Evaluation of a sinus venosus atrial septal defect by magnetic resonance: a case report., Rev Port Cardiol, Vol: 27, Pages: 1317-1321, ISSN: 0870-2551
Although superior sinus venosus is one of the major types of atrial septal defect (ASD), diagnosis is usually more difficult than the more common forms. We report a case in which cardiovascular magnetic resonance (CMR) was useful in evaluating a patient presenting with right heart dilatation. Besides establishing the diagnosis of atrial septal defect, it also documented the anomalous drainage of a pulmonary vein.
Alpendurada F, Mohiaddin R, 2008, Evaluation of marfan syndrome by cardiovascular magnetic resonance, EUROPEAN HEART JOURNAL, Vol: 29, Pages: 498-498, ISSN: 0195-668X
Peake STC, Mason JC, Mittal T, et al., 2008, Growing pains - and a heart attack, LANCET, Vol: 372, Pages: 600-600, ISSN: 0140-6736
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