Marked changes in intervertebral disc morphology in ochronosis of alkaptonuria (AKU): a quantitative analysis of lumbar spine MR images

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1 Marked changes in intervertebral disc morphology in ochronosis of alkaptonuria (AKU): a quantitative analysis of lumbar spine MR images Poster No.: C-2314 Congress: ECR 2011 Type: Authors: Keywords: DOI: Scientific Exhibit A. Todd-Pokropek; London/UK Spine, Musculoskeletal bone, Musculoskeletal joint, Musculoskeletal spine, MR, Computer Applications-Detection, diagnosis, Congenital /ecr2011/C-2314 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 7

2 Purpose This study aims at quantifying the effect of Alkaptonuria (AKU) on intervertebral disc morphology by analysing lumbar spine MRI. But what is AKU? It is a rare metabolic disease caused by the lack of enzyme homogentisate 1, 2 dioxygenase -HGD. It is the first human disorder to be shown to follow a pattern of Mendelian inheritance. In AKU, the amino acids tyrosine and phenylalanine cannot be fully metabolized, but are broken down to homogentisic acid -HGA. The high circulating HGA is converted to a polymeric pigment which damages cartilage -Ochronosis. In the spine, AKU results in severe spondyloarthropathy. The FindAKUre project of the University of Liverpool looks into the causes of Alkaptonuria aiming to provide a fundamental understanding of the disease and to develop potential therapies. This poster presents a quantitative diagnostic tool which is intended to support disease follow-up and the assesment of treatment. Images for this section: Page 2 of 7

3 Fig. 1: T2 weight MR images: (left) 60 years old AKU patient and (right) matched control Page 3 of 7

4 Methods and Materials 10 AKU patients data (age years) and 10 age- and sex-matched non-aku subjects (age years) are analyzed in this study. Specifically: Saggital T2 weighted MR images were obtained in the MARIARC centre using standardized acquisition protocols on an 1.5 Tesla Siemens Symphony scanner. A custom made computerized tool was exploited for disc segmentation and quantification from MRI (see Figure). Morphological information representing intervertebral disc height, area and shape compactness was extracted from the MR images. For each subject 5 discs were analysed and a mean calculated, and AKU and control groups were compared by t-test. Images for this section: Fig. 1: Outline of the quantification method Page 4 of 7

5 Results In comparison to controls the AKU discs displayed: reduced area and height indicating advanced disc degeneration specifically AKU disc area is 262 ± 103 mm 2 for the controls, while AKU disc height is 8.7±2.5 mm versus 12.8 ± 2.1 mm. versus 392 ± 94 mm reduced compactness consistent with end plate damage and osteophytosis specifically AKU disc compactness is 0.73 ± 0.10 versus 0.84 ± 0.08 for the controls Statistical analysis revealed significant differences between AKU and control discs morphology (p<0.01) Images for this section: Fig. 1: Comparative example illustrating the morphological differences between the AKU and control discs. AKU discs have reduced area, height and compactness which indicating a severe degenerative profile. Page 5 of 7

6 Conclusion This study presented a computer aided tool for the analysis of AKU. The quantitative analysis of MR images indicated a severe disc degenerative profile in AKU compared to age-matched controls. The proposed quantitative tool will support disease follow-up in a precise and objective manner. In future, we will apply this method for monitoring the new AKU treatment currently being investigated in the FindAKUre project. References 1. Alkaptonuria- a Review of Surgical and Autopsy Pathology. Helliwell TR, Gallagher JA, Ranganath L. Histopathology Alkaptonuria Presenting with Ochronotic Spondyloarthropathy. Al-Mahfoudh R, Clark S. Buxton N. British Journal of Neurosurgery Texture-Based.Quantification of Lumbar Intervertebral Disc degeneration from Conventional T2-weighted MRI, Michopoulou, S., Costaridou, L., Vlychou, M., Speller, R., Todd-Pokropek, A., Acta Radiologica Computer Aided Quantification of Lumbar Intervertebral Disc Degeneration in MRI. Michopoulou, S., Costaridou, L., Kazantzi, A., Panagiotopoulos, E., Speller, R., Panayiotakis, G., Todd-Pokropek, A. UK Radiological Conference (UKRC), Personal Information Sofia Michopoulou / Andrew Todd-Pokropek Department of Medical Physics and Bioengineering, University College London s.michopoulou@ucl.ac.uk, a.todd@ucl.ac.uk Page 6 of 7

7 Valerie Adams / Graham J Kemp Magnetic Resonance and Image Analysis Research Centre (MARIARC), University of Liverpool VAdams@liverpool.ac.uk / G.J.Kemp@liverpool.ac.uk Lakshminarayan Ranganath Department of Clinical Biochemistry and Metabolic Medicine, Royal Liverpool University Hospital lrang@liverpool.ac.uk James A Gallagher Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of Liverpool J.A.Gallagher@liverpool.ac.uk Page 7 of 7