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154 results on '"Mortensen, Kristian H."'

1. Real-time Assessment of Right and Left Ventricular Volumes and Function in Children Using High Spatiotemporal Resolution Spiral bSSFP with Compressed Sensing

Author

Steeden, Jennifer A., Kowalik, Grzegorz T., Tann, Oliver, Hughes, Marina, Mortensen, Kristian H., and Muthurangu, Vivek

Subjects
Physics - Medical Physics
Abstract

Background: Real-time (RT) assessment of ventricular volumes and function enables data acquisition during free-breathing. However, in children the requirement for high spatiotemporal resolution requires accelerated imaging techniques. In this study, we implemented a novel RT bSSFP spiral sequence reconstructed using Compressed Sensing (CS) and validated it against the breath-hold (BH) reference standard for assessment of ventricular volumes in children with heart disease. Methods: Data was acquired in 60 children. Qualitative image scoring and evaluation of ventricular volumes was performed by 3 clinical cardiac MR specialists. 30 cases were reassessed for intra-observer variability, and the other 30 cases for inter-observer variability. Results: Spiral RT images were of good quality, however qualitative scores reflected more residual artefact than standard BH images and slightly lower edge definition. Quantification of Left Ventricular (LV) and Right Ventricular (RV) metrics showed excellent correlation between the techniques with narrow limits of agreement. However, we observed small but statistically significant overestimation of LV end-diastolic volume, underestimation of LV end-systolic volume, as well as a small overestimation of RV stroke volume and ejection fraction using the RT imaging technique. No difference in inter-observer or intra-observer variability were observed between the BH and RT sequences. Conclusions: Real-time bSSFP imaging using spiral trajectories combined with a compressed sensing reconstruction is feasible. The main benefit is that it can be acquired during free breathing. However, another important secondary benefit is that a whole ventricular stack can be acquired in ~20 seconds, as opposed to ~6 minutes for standard BH imaging. Thus, this technique holds the potential to significantly shorten MR scan times in children.

Published
2018

7. Bone Mineral Density and Vascular Calcification in Children and Young Adults With CKD 4 to 5 or on Dialysis

Author

Lalayiannis, Alexander D., primary, Crabtree, Nicola J., additional, Ferro, Charles J., additional, Wheeler, David C., additional, Duncan, Neill D., additional, Smith, Colette, additional, Popoola, Joyce, additional, Varvara, Askiti, additional, Mitsioni, Andromachi, additional, Kaur, Amrit, additional, Sinha, Manish D., additional, Biassoni, Lorenzo, additional, McGuirk, Simon P., additional, Mortensen, Kristian H., additional, Milford, David V., additional, Long, Jin, additional, Leonard, Mary D., additional, Fewtrell, Mary, additional, and Shroff, Rukshana, additional

Published
2022
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9. Enhanced 3D visualization for planning biventricular repair of double outlet right ventricle: a pilot study on the advantages of virtual reality

Author

Milano, Elena Giulia, primary, Kostolny, Martin, additional, Pajaziti, Endrit, additional, Marek, Jan, additional, Regan, William, additional, Caputo, Massimo, additional, Luciani, Giovanni Battista, additional, Mortensen, Kristian H, additional, Cook, Andrew C, additional, Schievano, Silvia, additional, and Capelli, Claudio, additional

Published
2021
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10. The burden of subclinical cardiovascular disease in children and young adults with chronic kidney disease and on dialysis

Author

Lalayiannis, Alexander D, primary, Ferro, Charles J, additional, Wheeler, David C, additional, Duncan, Neill D, additional, Smith, Colette, additional, Popoola, Joyce, additional, Askiti, Varvara, additional, Mitsioni, Andromachi, additional, Kaur, Amrit, additional, Sinha, Manish D, additional, McGuirk, Simon P, additional, Mortensen, Kristian H, additional, Milford, David V, additional, and Shroff, Rukshana, additional

Published
2021
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18. Additional file 2 of Rapid whole-heart CMR with single volume super-resolution

Author

Steeden, Jennifer A., Quail, Michael, Gotschy, Alexander, Mortensen, Kristian H., Hauptmann, Andreas, Arridge, Simon, Jones, Rodney, and Muthurangu, Vivek

Abstract

Additional file 2. Flow diagram showing the steps taken to convert the high-resolution WH-bSSFP data, to synthetic low-resolution WH-bSSFP data used to train/test the residual U-Net.

Published
2020
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21. Rapid whole-heart CMR with single volume super-resolution

Author

Steeden, Jennifer A, Quail, Michael, Gotschy, Alexander, Mortensen, Kristian H, Hauptmann, Andreas, Arridge, Simon, Jones, Rodney, Muthurangu, Vivek, Steeden, Jennifer A, Quail, Michael, Gotschy, Alexander, Mortensen, Kristian H, Hauptmann, Andreas, Arridge, Simon, Jones, Rodney, and Muthurangu, Vivek

Abstract

BACKGROUND Three-dimensional, whole heart, balanced steady state free precession (WH-bSSFP) sequences provide delineation of intra-cardiac and vascular anatomy. However, they have long acquisition times. Here, we propose significant speed-ups using a deep-learning single volume super-resolution reconstruction, to recover high-resolution features from rapidly acquired low-resolution WH-bSSFP images. METHODS A 3D residual U-Net was trained using synthetic data, created from a library of 500 high-resolution WH-bSSFP images by simulating 50% slice resolution and 50% phase resolution. The trained network was validated with 25 synthetic test data sets. Additionally, prospective low-resolution data and high-resolution data were acquired in 40 patients. In the prospective data, vessel diameters, quantitative and qualitative image quality, and diagnostic scoring was compared between the low-resolution, super-resolution and reference high-resolution WH-bSSFP data. RESULTS The synthetic test data showed a significant increase in image quality of the low-resolution images after super-resolution reconstruction. Prospectively acquired low-resolution data was acquired ~× 3 faster than the prospective high-resolution data (173 s vs 488 s). Super-resolution reconstruction of the low-resolution data took < 1 s per volume. Qualitative image scores showed super-resolved images had better edge sharpness, fewer residual artefacts and less image distortion than low-resolution images, with similar scores to high-resolution data. Quantitative image scores showed super-resolved images had significantly better edge sharpness than low-resolution or high-resolution images, with significantly better signal-to-noise ratio than high-resolution data. Vessel diameters measurements showed over-estimation in the low-resolution measurements, compared to the high-resolution data. No significant differences and no bias was found in the super-resolution measurements in any of the great vessels. However, a

Published
2020

28. Coronary plaque burden in Turner syndrome a coronary computed tomography angiography study

Author

Funck, Kristian L., primary, Budde, Ricardo P. J., additional, Viuff, Mette H., additional, Wen, Jan, additional, Jensen, Jesper M., additional, Nørgaard, Bjarne L., additional, Bons, Lidia R., additional, Duijnhouwer, Anthonie L., additional, Dey, Damini, additional, Mortensen, Kristian H., additional, Andersen, Niels H., additional, Roos-Hesselink, Jolien W., additional, and Gravholt, Claus H., additional

Published
2020
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31. Dilation of the ascending aorta in Turner syndrome - a prospective cardiovascular magnetic resonance study

Author

Pedersen Erik M, Hørlyck Arne, Lundorf Erik, Sørensen Keld, Andersen Niels H, Stochholm Kirstine, Hjerrild Britta E, Mortensen Kristian H, Christiansen Jens S, and Gravholt Claus H

Subjects
Diseases of the circulatory (Cardiovascular) system, RC666-701
Abstract

Abstract Background The risk of aortic dissection is 100-fold increased in Turner syndrome (TS). Unfortunately, risk stratification is inadequate due to a lack of insight into the natural course of the syndrome-associated aortopathy. Therefore, this study aimed to prospectively assess aortic dimensions in TS. Methods Eighty adult TS patients were examined twice with a mean follow-up of 2.4 ± 0.4 years, and 67 healthy age and gender-matched controls were examined once. Aortic dimensions were measured at nine predefined positions using 3D, non-contrast and free-breathing cardiovascular magnetic resonance. Transthoracic echocardiography and 24-hour ambulatory blood pressure were also performed. Results At baseline, aortic diameters (body surface area indexed) were larger at all positions in TS. Aortic dilation was more prevalent at all positions excluding the distal transverse aortic arch. Aortic diameter increased in the aortic sinus, at the sinotubular junction and in the mid-ascending aorta with growth rates of 0.1 - 0.4 mm/year. Aortic diameters at all other positions were unchanged. The bicuspid aortic valve conferred higher aortic sinus growth rates (p < 0.05). No other predictors of aortic growth were identified. Conclusion A general aortopathy is present in TS with enlargement of the ascending aorta, which is accelerated in the presence of a bicuspid aortic valve.

Published
2011
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34. Thoracic aortopathy in Turner syndrome and the influence of bicuspid aortic valves and blood pressure: a CMR study

Author

Hager Alfred, Hørlyck Arne, Hansen Klavs W, Lundorf Erik, Andersen Niels H, Pedersen Erik M, Sørensen Keld E, Mortensen Kristian H, Hjerrild Britta E, Christiansen Jens S, and Gravholt Claus H

Subjects
Diseases of the circulatory (Cardiovascular) system, RC666-701
Abstract

Abstract Background To investigate aortic dimensions in women with Turner syndrome (TS) in relation to aortic valve morphology, blood pressure, karyotype, and clinical characteristics. Methods and results A cross sectional study of 102 women with TS (mean age 37.7; 18-62 years) examined by cardiovascular magnetic resonance (CMR- successful in 95), echocardiography, and 24-hour ambulatory blood pressure. Aortic diameters were measured by CMR at 8 positions along the thoracic aorta. Twenty-four healthy females were recruited as controls. In TS, aortic dilatation was present at one or more positions in 22 (23%). Aortic diameter in women with TS and bicuspid aortic valve was significantly larger than in TS with tricuspid valves in both the ascending (32.4 ± 6.7 vs. 26.0 ± 4.4 mm; p < 0.001) and descending (21.4 ± 3.5 vs. 18.8 ± 2.4 mm; p < 0.001) aorta. Aortic diameter correlated to age (R = 0.2 - 0.5; p < 0.01), blood pressure (R = 0.4; p < 0.05), a history of coarctation (R = 0.3; p = 0.01) and bicuspid aortic valve (R = 0.2-0.5; p < 0.05). Body surface area only correlated with descending aortic diameter (R = 0.23; p = 0.024). Conclusions Aortic dilatation was present in 23% of adult TS women, where aortic valve morphology, age and blood pressure were major determinants of the aortic diameter.

Published
2010
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35. List of Contributors

Author

Adams, Ashok, Addley, Helen, Agosto, Omar, Al Sarraf, Abdullah A., Alobeidi, Farah, Ameli-Renani, Seyed, Argyropoulou, Maria I., Arthurs, Owen, Balériaux, Danielle, Barber, Joy L., Barentsz, Jelle O., Barkhof, Frederik, Barnett, Joseph L., Barras, Christen D., Barrett, Tristan, Beale, Timothy, Beddy, Peter, Beigelman-Aubry, Catherine, Belli, Anna-Maria, Bhalla, Sanjeev, Bhattacharya, Joti Jonathan, Bogaert, Jan, Bomers, Joyce G.R., Boone, Darren, Bordonaro, Veronica, Breen, David J., Brillet, Pierre-Yves, Campbell, Robert S.D., Campion, Tom, Carey, Brian, Caroline, Dina F., Cazzato, Roberto Luigi, Chateil, Jean-François, Choudhury, Ananya, Chun, Joo-Young, Cook, Gary J.R., Copley, Susan J., Dass, Chandra, Davagnanam, Indran, Davies, A. Mark, Davies, Alun, de Rooij, Maarten, de Roos, Albert, Desai, Sujal R., Devaraj, Anand, Doran, Simon P., Easty, Marina, Evans, Andrew J., Fattori, Rossella, Fetita, Catalin I., Franquet, Tomás, Freeman, Alan H., Freeman, Susan, Gallagher, Ferdia A., Gangi, Afshin, Gibson, Robert N., Gillard, Jonathan H., Gleeson, Fergus, Godfrey, Edmund M., Goh, Vicky, Anson, Beatriz Gomez, Grainger, Andrew J., Granata, Claudio, Grenier, Philippe A., Gunny, Roxana S., Hadi, Mohammed, Hakim, Wasim, Hall, Charles B.O., Hamady, Mohamad, Hartmann, Ieneke J.C., Heaney, Roisin M., Hoskin, Peter, Hughes, Philip M., Humphries, Paul D., Jäger, H. Rolf, James, Steven L.J., James, Jonathan J., Javidan-Nejad, Cylen, Jawad, Susan, Johnson, Karl, Jones, Hefin, Jones, Brynmor P., Kapoor, Geeta, Kasthuri, Ram S., Katsanos, Konstantinos, Kavanagh, Richard G., Keeling, Aoife N., Kelly-Morland, Christian, Kenny, Lizbeth M., Kilburn-Toppin, Fleur, Kolokythas, Orpheus, Kopf, Helmut, Kremer, Stéphane, Krestan, Christian R., Kroft, Lucia J.M., Lagha, Eamon, Lalam, Radhesh, Lee, Michael J., Lomas, David J., Lovato, Luigi, MacVicar, David, Maher, Michael M., Mannelli, Lorenzo, Martin, Rachel M., Matys, Tomasz, McLaughlin, Patrick D., McNally, Eugene, Meaney, James F.M., Mehta, Amrish, Meirelles, Gustavo, Micallef, Caroline, Mistry, Alpesh, Miszkiel, Katherine, Morgan, Robert A., Mortensen, Kristian H., Moss, Jonathan G., Murray, Timothy E., Nair, Arjun, Nandra, Gurinder S., Natale, Luigi, O'Connor, Owen J., O'Connor, Philip, O'Donnell, Paul, Offiah, Amaka C., Olsen, Øystein E., Müller, Lil-Sofie Ording, O'Regan, Kevin, Owens, Catherine M., Padley, Simon P.G., Parizel, Paul M., Parkar, Nadeem, Patel, Anish, Patel, Uday, Patsch, Janina M., Pizzini, Francesca Benedetta, Plumb, Andrew, Popat, Sanjay, Power, Stephen P., Prezzi, Davide, Quail, Michael A., Rankine, James J., Ratnam, Lakshmi, Rawal, Bhavin, Reekers, Jim A., Reynolds, John H., Reznek, Rodney H., Riccabona, Michael, Rosendahl, Karen, Rottenberg, Giles, Rovira, Àlex, Rowbotham, Emma L., Russo, Vincenzo, Rutherford, Elizabeth E., Sabharwal, Tarun, Sahdev, Anju, Saifuddin, Asif, Sala, Evis, Saunders, Dawn E., Schima, Wolfgang, Scoffings, Daniel J., Screaton, Nicholas J., Sellon, Edward, Semple, Thomas R., Serrao, Eva M., Shaida, Nadeem, Shakur, Amreen, Sheikh-Bahaei, Nasim, Shepherd, Beth, Siebelink, Hans-Marc J., Silva, Mario, Singh, Jaspreet, Smith, Jan, Sundgren, Pia C., Sutherland, Tom R., Sverzellati, Nicola, Symons, Rolf, Taylor, Andrew M., Taylor, Stuart A., Thakor, Avnesh S., Thurnher, Majda M., Thust, Steffie, Toms, Andoni P., Tsakok, Maria, Tyler, Philippa, Uberoi, Raman, van den Hauwe, Luc, van Goethem, Johan W., Thielen, Thomas Van, Varghese, Sibu, Verma, Hema, Verschakelen, Johny A., Villeirs, Geert M., Vinnicombe, Sarah J., Warbey, Victoria S., Watson, Tom A., Westenberg, Jos J.M., Yadavali, Reddi Prasad, and Yamamoto, Adam Kenji

Published
2021
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38. Continuous measurement of aortic dimensions in Turner syndrome: a cardiovascular magnetic resonance study

Author

Subramaniam, Dhananjay Radhakrishnan, primary, Stoddard, William A., additional, Mortensen, Kristian H., additional, Ringgaard, Steffen, additional, Trolle, Christian, additional, Gravholt, Claus H., additional, Gutmark, Ephraim J., additional, Mylavarapu, Goutham, additional, Backeljauw, Philippe F., additional, and Gutmark-Little, Iris, additional

Published
2017
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40. TIMP3 and TIMP1 are risk genes for bicuspid aortic valve and aortopathy in Turner syndrome.

Author

Corbitt, Holly, Morris, Shaine A., Gravholt, Claus H., Mortensen, Kristian H., Tippner-Hedges, Rebecca, Silberbach, Michael, Maslen, Cheryl L., and null, null

Subjects
AORTIC valve diseases, TURNER'S syndrome, MEDICAL genetics, DISEASE risk factors, ETIOLOGY of diseases
Abstract

Turner syndrome is caused by complete or partial loss of the second sex chromosome, occurring in ~1 in 2,000 female births. There is a greatly increased incidence of aortopathy of unknown etiology, including bicuspid aortic valve (BAV), thoracic aortic aneurysms, aortic dissection and rupture. We performed whole exome sequencing on 188 Turner syndrome participants from the National Registry of Genetically Triggered Thoracic Aortic Aneurysms and Cardiovascular Related Conditions (GenTAC). A gene-based burden test, the optimal sequence kernel association test (SKAT-O), was used to evaluate the data with BAV and aortic dimension z-scores as covariates. Genes on chromosome Xp were analyzed for the potential to contribute to aortopathy when hemizygous. Exome analysis revealed that TIMP3 was associated with indices of aortopathy at exome-wide significance (p = 2.27 x 10−7), which was replicated in a separate cohort. The analysis of Xp genes revealed that TIMP1, which is a functionally redundant paralogue of TIMP3, was hemizygous in >50% of our discovery cohort and that having only one copy of TIMP1 increased the odds of having aortopathy (OR = 9.76, 95% CI = 1.91–178.80, p = 0.029). The combinatorial effect of a single copy of TIMP1 and TIMP3 risk alleles further increased the risk for aortopathy (OR = 12.86, 95% CI = 2.57–99.39, p = 0.004). The products of genes encoding tissue inhibitors of matrix metalloproteinases (TIMPs) are involved in development of the aortic valve and protect tissue integrity of the aorta. We propose that the combination of X chromosome TIMP1 hemizygosity and variants of its autosomal paralogue TIMP3, significantly increases the risk of aortopathy in Turner syndrome. [ABSTRACT FROM AUTHOR]

Published
2018
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41. Coagulation and fibrinolytic disturbances are related to carotid intima thickness and arterial blood pressure in Turner syndrome

Author

Gravholt, Claus H, Mortensen, Kristian H, Andersen, Niels H, Ibsen, Liselotte, Ingerslev, Jørgen, and Hjerrild, Britta E

Abstract

Objective: Turner syndrome (TS) is characterised by growth retardation, hypogonadism and a high risk of cardiovascular complications and atherosclerosis; case reports suggests that thrombo-embolic complications may be present. Design: Cross-sectional study. Patients: 60 women with TS. Measurements: We characterised the activities of the haemostatic system, elucidated by assessment of a panel of clotting factors and thrombosis risk factors, and related these findings to carotid intima thickness (CIMT) and blood pressure. Results: Most (81%) received hormone replacement therapy. The medians of all measured factors and inflammatory parameters were not different from normative data, but many cases displayed values of CRP (40%), fibrinogen (15%), fibrin D-dimer (15%), factor VIII (25%), von Willebrand factor (vWF) (15%), cholesterol and liver parameters that were greater than normative limits. CRP, fibrinogen, vWF, factor VIII and liver parameters were highly and positively correlated. Haemostatic variables were positively related to both CIMT and blood pressure. The Factor V Leiden G1691A gene polymorphism heterozygosity was detected in 12.5%. Conclusion: We describe a significant proportion of individual TS females having high levels of vWF, factor VIII, fibrinogen and CRP (15-40%) and an increased frequency of the Leiden mutation, with important associations to CIMT and blood pressure, suggesting that a subset of TS may have an unfavourable haemostatic balance, which may contribute to the increased risk of premature ischemic heart disease and possibly increase the risk of deep venous and portal vein thrombosis.

Published
2012

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