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Ένα από τα βασικά χαρακτηριστικά της ομόζυγης β-θαλασσαιμίας είναι η οστεοπάθεια, η οποία αποτελεί μία πολυπαραγοντική διαταραχή, που δεν έχει πλήρως διευκρινισθεί. Μελετήσαμε τους οσφυϊκούς σπονδύλους 48 ασθενών με τις μεθόδους Dual-Energy X-ray Absorptiometry (DXA) και Quantitative Computed Tomography (QCT), και εστιάσαμε στις δομικές οστικές ιδιότητες, όπως προσδιορίζονται από την υψηλής ευκρίνειας Υπολογιστική τομογραφία (HRCT). Οι τιμές της οστικής πυκνότητας (BMD values) εκφράσθηκαν ως Z-scores και τα αποτελέσματα συσχετίσθηκαν. Εκτιμήθηκε η επίδραση της ηλικίας, του φύλου, του τύπου της θαλασσαιμίας και των ορμονικών παραγόντων στις τιμές ΒΜD. Αξιολογήσαμε, με βάση την HRCT, την ακεραιότητα του φλοιού και τον αριθμό και πάχος των δοκίδων της σπογγώδους ουσίας. Με βάση τον αριθμό των δοκίδων ταξινομήσαμε τους ασθενείς σε κλίμακα τριών βαθμίδων. Τα αποτελέσματά μας έδειξαν ότι ο συνολικός επιπολασμός της οστεοπόρωσης με την μέθοδο DXA ήταν 44 % και με την QCT 6 %. Και οι δύο μέθοδοι έδειξαν μία αρνητική συσχέτιση μεταξύ της ηλικίας και της BMD, ενώ οι ορμονικοί παράγοντες παρουσίασαν συσχετίσεις τόσο με τις μετρήσεις της QCT όσο και με τις αντίστοιχες της DXA. Ο συντελεστής συσχέτισης μεταξύ της BMD της DXA και της σπογγώδους BMD της QCT ήταν 0,545 (p<0,001) ενώ η αντίστοιχη τιμή για τα Ζ-scores ήταν 0,491 (p<0,001). Η ομαδοποίηση των ασθενών σε φυσιολογικούς, οστεοπενικούς και οστεοπορωτικούς, με βάση το Ζ της QCT, ήταν σε καλύτερη συμφωνία με την ταξινόμηση με βάση τον αριθμό των δοκίδων (K=0,209, p=0,053), σε σύγκριση με την ομαδοποίηση σύμφωνα με το Ζ της μεθόδου DXA (K=0,145, p=0,120). Η εκτίμηση του φλοιού με την HRCT έδειξε διακοπές στη συνέχειά του σε 15 ασθενείς. Και οι δύο μέθοδοι δείχνουν μία επιδείνωση της οστεοπόρωσης με την πρόοδο της ηλικίας. Η ανεπάρκεια των ορμονών συσχετίζεται με την θαλασσαιμική οστεοπόρωση, ενώ η οτπική εκτίμηση του φλοιώδους οστού δείχνει ότι οι ενδιάμεσου τύπου θαλασσαιμικοί πάσχουν σε μεγαλύτερο βαθμό από τους ασθενείς με μείζονα μορφή θαλασσαιμίας. Με τον αριθμό των δοκίδων ως δείκτη οστεοπόρωσης, φαίνεται ότι η QCT μπορεί να εκτιμήσει την οστεοπάθεια καλύτερα από την DXA. Δεδομένου ότι η QCT έχει την ικανότητα να μετρήσει την οστική πυκνότητα του σπογγώδους και φλοιώδους οστού, ξεχωριστά, μπορεί να παρέχει πρώιμη ένδειξη του ποιο από τα δύο μεταβάλλεται πιο γρήγορα και σε τι βαθμό. - / Osteopathy, as a major feature of homozygous beta-thalassaemia, is a multifactorial disorder, not fully understood. We studied the lumbar vertebrae of 48 patients using Dual-Energy X-ray Absorptiometry (DXA) and Quantitative Computed Tomography (QCT), and we focused on structural properties, assessed by High Resolution Computed Tomography (HRCT). Bone Mineral Density (BMD) values were expressed as Z scores and the results were correlated. The effect of age, sex, type of thalassaemia and hormonal factors on BMD was assessed. We estimated, with HRCT, the cortex integrity and the number and thickness of trabeculae; the latter were classified to a three-grade scale. Our results showed the overall prevalence of osteoporosis to be 44 % with DXA and 6 % with QCT. Both techniques revealed an inverse correlation between age and BMD, whereas hormonal factors demonstrated associations with QCT and DXA measurements. The correlation coefficient between DXA’s BMD and QCT’s trabecular BMD was 0.545 (p<0.001) whereas the corresponding value for Z scores was r=0.491 (p<0.001). The classification of the patients into normal, osteopenic and osteoporotic categories, using QCT’s Z, was in better agreement with the assignment based on trabecular number (K=0.209, p=0.053) than the classification using DXA’s Z (K=0.145, p=0.120). Cortex evaluation by HRCT showed discontinuity in 15 patients. Both methods indicate a progression of osteoporosis with age. Hormonal deficiency is associated with thalassaemic osteoporosis whereas the visual estimation of cortex indicate that TI could be more affected than TM. Using the trabecular number as an indicator of osteoporosis, it seems that QCT may evaluate osteopathy better than DXA. Since the former has the ability to measure trabecular and cortical BMD separately, it could give early indication of which changes more rapidly and to what degree.

Orientador: Guilherme de Paula Nogueira / Banca: Yuri Tani Utsunomiya / Banca: Marco Antonio Rodrigues Fernandes / Resumo: O objetivo desse estudo foi inferir a Densidade Mineral óssea (DMO) a partir da imagem radiográfica (Raios-X) usando como referência a DMO de uma escada de alumínio mensurada por Absorciometria por de Duas-Energias (DXA). Para isso foram utilizadas 30 amostras de tecido ósseo cortical e 30 amostras de tecido ósseo trabecular de osso bovino "in vitro". Foram mensurados neste estudo a Densidade Mineral Óssea (DMO), o Conteúdo Mineral Ósseo (CMO) ambos obtidos pelo densitômetro LUNAR®-DPX ALPHA; a Quantidade Mineral Óssea (QMO) massa das cinzas após a calcinação das amostras; a densidade real das amostras (dReal=massa/volume). Foram feitas 10 tomadas de RX com as 60 amostras, entremeadas pela escada de alumínio (referencial densitométrico). A correlação entre as técnicas (DR-tons de cinza e DXA g/cm2) gerou equações de regressão para cada uma das dez radiografias e permitiu inferir a densidade mineral óssea (DMODR), obtida através da conversão dos tons de cinza em densidade radiográfica pelo software ImageJ® para cada uma das 10 tomadas radiográficas; calculou-se então a média da densidade mineral óssea calculada pela densitometria radiográfica (XDMODR) de todas as dez radiografias. Foi observado que a média da densidade real das amostras foi de 2,2±0,23g/cm2 e 1,05±0,09g/cm2 enquanto que a média da densidade mensurada pelo DXA foi de 0,73±0,11g/cm2 e 0,22±0,11g/cm2, observou que a media da DMODR ficou em 0,93±0,11g/cm2 e 0,34±0,14 g/cm2 para o osso cortical e trabecular respect... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of this study was to infer the bone mineral density (BMD) from the radiographic image (X-X) with reference to the BMD of an aluminum step wedge measured by absorptiometry Dual-energy (DXA). For this we used 30 samples of cortical bone 30 and cancellous bone tissue samples of bovine bone "in vitro". Were measured in this study Bone Mineral Density (BMD), bone mineral content (BMC) both obtained by densitometer LUNAR® DPX-ALPHA; Volume Bone Mineral (QMO) mass of ash after calcination of the samples; the real density of the samples (dReal = mass / volume). 10 taken RX were made with the samples 60, interspersed by aluminum step wedge (densitometric reference). The correlation between the techniques (gray DR-tones and DXA g / cm 2) generated regression equations for each of the ten X-rays and allowed to infer bone mineral density (DMODR) obtained by converting grayscale radiographic density by ImageJ® for each of the 10 radiographic taken. It was then calculated average bone mineral density calculated by X-ray densitometry (XDMODR) radiographs of all ten. Was observed that the average true density of the samples was 2.2±0.23g/cm2 and 1.05±0.09g/cm2 while the average density measured by DXA was 0.73±0.11g/cm2 and 0.22±0.11g/cm2 interesting that the average DMODR was 0.93±0.11g/cm2 and 0.34±0.14g/cm2 for cortical and cancellous bone respectively. The average of the BMC was 0.19±0.08g and 0.9±0.02g, and the average QMO 0.14±0.04g and 0.05±0 03g for cortical and cancellous bo... (Complete abstract click electronic access below) / Mestre

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Atenciosamente Ederson Vasconcelos Pereira on 2019-01-29T12:46:31Z (GMT) / Submitted by Rodrigo Antonio Fernandes (rodrigoantoniofernandes@yahoo.com.br) on 2019-01-29T13:37:47Z No. of bitstreams: 2 Fernandes_RA dissert.pdf: 2677985 bytes, checksum: 59bf1c4dbeabd618fa2d4e2bfe9922fa (MD5) ata e aprovação.pdf: 653292 bytes, checksum: bcfcb8279087f3106d7831c31b686782 (MD5) / Approved for entry into archive by Ederson Vasconcelos Pereira null (edersonpereira@fmva.unesp.br) on 2019-01-29T18:18:15Z (GMT) No. of bitstreams: 1 fernandes_ra_me_araca_int.pdf: 2718642 bytes, checksum: 4dea3e0dc607519bbdbdb41a172e9277 (MD5) / Made available in DSpace on 2019-01-29T18:18:15Z (GMT). No. of bitstreams: 1 fernandes_ra_me_araca_int.pdf: 2718642 bytes, checksum: 4dea3e0dc607519bbdbdb41a172e9277 (MD5) Previous issue date: 2019-01-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo desse estudo foi inferir a Densidade Mineral óssea (DMO) a partir da imagem radiográfica (Raios-X) usando como referência a DMO de uma escada de alumínio mensurada por Absorciometria por de Duas-Energias (DXA). Para isso foram utilizadas 30 amostras de tecido ósseo cortical e 30 amostras de tecido ósseo trabecular de osso bovino “in vitro”. Foram mensurados neste estudo a Densidade Mineral Óssea (DMO), o Conteúdo Mineral Ósseo (CMO) ambos obtidos pelo densitômetro LUNAR®–DPX ALPHA; a Quantidade Mineral Óssea (QMO) massa das cinzas após a calcinação das amostras; a densidade real das amostras (dReal=massa/volume). Foram feitas 10 tomadas de RX com as 60 amostras, entremeadas pela escada de alumínio (referencial densitométrico). A correlação entre as técnicas (DR-tons de cinza e DXA g/cm2) gerou equações de regressão para cada uma das dez radiografias e permitiu inferir a densidade mineral óssea (DMODR), obtida através da conversão dos tons de cinza em densidade radiográfica pelo software ImageJ® para cada uma das 10 tomadas radiográficas; calculou-se então a média da densidade mineral óssea calculada pela densitometria radiográfica (XDMODR) de todas as dez radiografias. Foi observado que a média da densidade real das amostras foi de 2,2±0,23g/cm2 e 1,05±0,09g/cm2 enquanto que a média da densidade mensurada pelo DXA foi de 0,73±0,11g/cm2 e 0,22±0,11g/cm2, observou que a media da DMODR ficou em 0,93±0,11g/cm2 e 0,34±0,14 g/cm2 para o osso cortical e trabecular respectivamente. A média da CMO foi de 0,19±0,9g e 0,08±0,02g e a media da QMO 0,14±0,04g e 0,05±0,03g para o osso cortical e trabecular respectivamente. Foi possível obter bons coeficientes de determinação entre todas as variáveis estudadas: CMO e QMO, R2 =0,747; DMO e dReal com R2 = 0,765; dReal e DMODR; DMO e XDMODR, respectivamente 0,764 e 0,856. Para as correlações foram usadas amostras de dois tecidos ósseos cortical e trabecular, o que sugere distinção entre as amostras com as metodologias utilizadas / The aim of this study was to infer the bone mineral density (BMD) from the radiographic image (X-X) with reference to the BMD of an aluminum step wedge measured by absorptiometry Dual-energy (DXA). For this we used 30 samples of cortical bone 30 and cancellous bone tissue samples of bovine bone "in vitro". Were measured in this study Bone Mineral Density (BMD), bone mineral content (BMC) both obtained by densitometer LUNAR® DPX-ALPHA; Volume Bone Mineral (QMO) mass of ash after calcination of the samples; the real density of the samples (dReal = mass / volume). 10 taken RX were made with the samples 60, interspersed by aluminum step wedge (densitometric reference). The correlation between the techniques (gray DR-tones and DXA g / cm 2) generated regression equations for each of the ten X-rays and allowed to infer bone mineral density (DMODR) obtained by converting grayscale radiographic density by ImageJ® for each of the 10 radiographic taken. It was then calculated average bone mineral density calculated by X-ray densitometry (XDMODR) radiographs of all ten. Was observed that the average true density of the samples was 2.2±0.23g/cm2 and 1.05±0.09g/cm2 while the average density measured by DXA was 0.73±0.11g/cm2 and 0.22±0.11g/cm2 interesting that the average DMODR was 0.93±0.11g/cm2 and 0.34±0.14g/cm2 for cortical and cancellous bone respectively. The average of the BMC was 0.19±0.08g and 0.9±0.02g, and the average QMO 0.14±0.04g and 0.05±0 03g for cortical and cancellous bone respectively. It was possible to obtain good determination coefficients between all variables: BMC and QMO, R2 = 0.747; BMD and dReal with R2 = 0.765; dReal and DMODR; BMD and XDMODR respectively 0.764 and 0.856. For correlations were used two samples of cortical and cancellous bone tissues, suggesting a difference between the samples with the methodologies used.