Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 5 uppsatser.

Thesis (M. Med. Sc.)--University of Hong Kong, 2004. / Also available in print.

Cardiovascular diseases (CVDs) constitute a leading cause of death, including premature death, in the developed world. The early diagnosis and treatment of CVDs is therefore of great importance. Modern imaging modalities enable the quantification and analysis of the cardiovascular system and provide researchers and clinicians with valuable tools for the diagnosis and treatment of CVDs. In particular, echocardiography offers a number of advantages, compared to other imaging modalities, making it a prevalent tool for assessing cardiac morphology and function. However, cardiac ultrasound images can suffer from a range of artifacts reducing their image quality and diagnostic value. As a result, there is great interest in the development of processing techniques that address such limitations. This thesis introduces and quantitatively evaluates four methods that enhance clinical cardiac ultrasound data by utilising information which until now has been predominantly disregarded. All methods introduced in this thesis utilise multiple partially uncorrelated instances of a cardiac cycle in order to acquire the information required to suppress or enhance certain image features. No filtering out of information is performed at any stage throughout the processing. This constitutes the main differentiation to previous data enhancement approaches which tend to filter out information based on some static or adaptive selection criteria. The first two image enhancement methods utilise spatial averaging of partially uncorrelated data acquired through a single acoustic window. More precisely, Temporal Compounding enhances cardiac ultrasound data by averaging partially uncorrelated instances of the imaged structure acquired over a number of consecutive cardiac cycles. An extension to the notion of spatial compounding of cardiac ultrasound data is 3D-to-2D Compounding, which presents a novel image enhancement method by acquiring and compounding spatially adjacent (along the elevation plane), partially uncorrelated, 2D slices of the heart extracted as a thin angular sub-sector of a volumetric pyramid scan. Data enhancement introduced by both approaches includes the substantial suppression of tissue speckle and cavity noise. Furthermore, by averaging decorrelated instances of the same cardiac structure, both compounding methods can enhance tissue structures, which are masked out by high levels of noise and shadowing, increasing their corresponding tissue/cavity detectability. The third novel data enhancement approach, referred as Dynamic Histogram Based Intensity Mapping (DHBIM), investigates the temporal variations within image histograms of consecutive frames in order to (i) identify any unutilised/underutilised intensity levels and (ii) derive the tissue/cavity intensity threshold within the processed frame sequence. Piecewise intensity mapping is then used to enhance cardiac ultrasound data. DHBIM introduces cavity noise suppression, enhancement of tissue speckle information as well as considerable increase in tissue/cavity contrast and detectability. A data acquisition and analysis protocol for integrating the dynamic intensity mapping along with spatial compounding methods is also investigated. The linear integration of DHBIM and Temporal Compounding forms the fourth and final implemented method, which is also quantitatively assessed. By taking advantage of the benefits and compensating for the limitations of each individual method, the integrated method suppresses cavity noise and tissue speckle while enhancing tissue/cavity contrast as well as the delineation of cardiac tissue boundaries even when heavily corrupted by cardiac ultrasound artifacts. Finally, a novel protocol for the quantitative assessment of the effect of each data enhancement method on image quality and diagnostic value is employed. This enables the quantitative evaluation of each method as well as the comparison between individual methods using clinical data from 32 patients. Image quality is assessed using a range of quantitative measures such as signal-to-noise ratio, tissue/cavity contrast and detectability index. Diagnostic value is assessed through variations in the repeatability level of routine clinical measurements performed on patient cardiac ultrasound scans by two experienced echocardiographers. Commonly used clinical measures such as the wall thickness of the Interventricular Septum (IVS) and the Left Ventricle Posterior Wall (LVPW) as well as the cavity diameter of the Left Ventricle (LVID) and Left Atrium (LAD) are employed for assessing diagnostic value.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 4 uppsatser.

Made available in DSpace on 2016-01-26T18:55:35Z (GMT). No. of bitstreams: 1 Mariana Paz Rodrigues.pdf: 560276 bytes, checksum: ef29af82731e0fa25f9dc58ae50f2640 (MD5) Previous issue date: 2012-09-28 / This study evaluates acupuncture effect in the prevention of arrhythmias induced by epinephrine crescent doses in rats. Were studied 26 Wistar rats, healthy males were divided into 2 groups: Group 1 (G1) - acupuncture for 30 minutes, points Pericardium 6 (Pc6) and Heart 7 (C7) before the intravenous administration of epinephrine, Group 2 (G2) - adrenaline, without performing acupuncture (control). In both groups, epinephrine was administered at an initial dose of 10 ug / kg by adding 5 ug / kg every 5 minutes until the final dose of 40 ug / kg. The ECG was recorded on continuous monitoring comparing the number of records changes in both groups. It was observed that the main changes produced by adrenaline were the occurrence of atrioventricular block of second degree (BAV2) (G1: 92.3% and G2: 100%) and bradycardia (G1: 69.2% and G2: 92.3%) in two groups. Less frequently, there was occurrence of nonsustained ventricular tachycardia (VT) (G1, G2 7.7% and 23.1%), extrasystoles (ES) isolated (G1: 92.3% - 14.5 ± 11.7 and G2: 100% - 24.9 ± 13.9) (p <0.5) and premature atrial complexes (PAC) (G1: 92.3% - 5.6 ± 7.2 and G2: 84.6% - 12.5 ± 9.5). During episodes of bradycardia and BAV2, we measured the time (in seconds) to restore the heart ratre to physiological levels (G1: 137.3 ± 117.4 and G2: 253.5 ± 151.1) (p <0, 5). It was concluded that acupuncture is effective in reducing occurrences of ES, and mitigate the effects of the Bezold-Jarisch reflex, being able to delay the occurrence of bradycardia and BAV2 and reduce recovery time until physiological rhythm, showing up as a promising tool in the prevention of cardiac arrhythmias. / Este estudo avalia o efeito da acupuntura na prevenção de arritmias induzidas por doses crescentes de adrenalina em ratos. Foram estudados 26 ratos Wistar, hígidos, machos, divididos em 2 grupos: Grupo 1 (G1) - acupuntura por 30 minutos, nos pontos Pericárdio 6 (Pc6) e Coração 7 (C7), antes da administração intravenosa de adrenalina; Grupo 2 (G2) administração de adrenalina, sem realização de acupuntura (controle). Em ambos os grupos, foi realizada a administração de adrenalina, na dose inicial de 10 ug/Kg, adicionando-se 5 ug/Kg, a cada 5 minutos, até a dose final de 40 ug/Kg. Realizou-se eletrocardiograma em monitorização contínua, comparando-se o número de registros de alterações em ambos os grupos. Observou-se que as principais alterações produzidas pela adrenalina foram ocorrência de bloqueio átrio-ventricular de 2º grau (BAV2) (G1: 92,3% e G2: 100%) e bradicardia (G1: 69,2% e G2: 92,3%) nos 2 grupos. Em menor frequência, verificou-se ocorrência de taquicardia ventricular (TV) não sustentada (G1: 7,7% e G2: 23,1%), extra-sístoles (ES) isoladas (G1: 92,3% - 14,5±11,7 e G2:100% - 24,9±13,9) (p<0,05) e complexos atriais prematuros (CAP) (G1: 92,3% - 5,6±7,2 e G2: 84,6% - 9,5±12,5). Durante os episódios de BAV2 e bradicardia, foi avaliado o tempo (em segundos) para restauração da frequência cardíaca a níveis fisiológicos (G1: 137,3±117,4 e G2: 253,5±151,1) (p<0,05). Conclui-se que a acupuntura é eficaz em reduzir ocorrências de ES, além de atenuar os efeitos do reflexo de Bezold-Jarisch, sendo capaz de retardar a ocorrência de BAV2 e bradicardia e reduzir o tempo de recuperação para ritmo fisiológico, mostrando-se como ferramenta promissora na prevenção de arritmias cardíacas.

Made available in DSpace on 2016-07-18T17:53:10Z (GMT). No. of bitstreams: 1 Mariana Paz Rodrigues.pdf: 560276 bytes, checksum: ef29af82731e0fa25f9dc58ae50f2640 (MD5) Previous issue date: 2012-09-28 / This study evaluates acupuncture effect in the prevention of arrhythmias induced by epinephrine crescent doses in rats. Were studied 26 Wistar rats, healthy males were divided into 2 groups: Group 1 (G1) - acupuncture for 30 minutes, points Pericardium 6 (Pc6) and Heart 7 (C7) before the intravenous administration of epinephrine, Group 2 (G2) - adrenaline, without performing acupuncture (control). In both groups, epinephrine was administered at an initial dose of 10 ug / kg by adding 5 ug / kg every 5 minutes until the final dose of 40 ug / kg. The ECG was recorded on continuous monitoring comparing the number of records changes in both groups. It was observed that the main changes produced by adrenaline were the occurrence of atrioventricular block of second degree (BAV2) (G1: 92.3% and G2: 100%) and bradycardia (G1: 69.2% and G2: 92.3%) in two groups. Less frequently, there was occurrence of nonsustained ventricular tachycardia (VT) (G1, G2 7.7% and 23.1%), extrasystoles (ES) isolated (G1: 92.3% - 14.5 ± 11.7 and G2: 100% - 24.9 ± 13.9) (p <0.5) and premature atrial complexes (PAC) (G1: 92.3% - 5.6 ± 7.2 and G2: 84.6% - 12.5 ± 9.5). During episodes of bradycardia and BAV2, we measured the time (in seconds) to restore the heart ratre to physiological levels (G1: 137.3 ± 117.4 and G2: 253.5 ± 151.1) (p <0, 5). It was concluded that acupuncture is effective in reducing occurrences of ES, and mitigate the effects of the Bezold-Jarisch reflex, being able to delay the occurrence of bradycardia and BAV2 and reduce recovery time until physiological rhythm, showing up as a promising tool in the prevention of cardiac arrhythmias. / Este estudo avalia o efeito da acupuntura na prevenção de arritmias induzidas por doses crescentes de adrenalina em ratos. Foram estudados 26 ratos Wistar, hígidos, machos, divididos em 2 grupos: Grupo 1 (G1) - acupuntura por 30 minutos, nos pontos Pericárdio 6 (Pc6) e Coração 7 (C7), antes da administração intravenosa de adrenalina; Grupo 2 (G2) administração de adrenalina, sem realização de acupuntura (controle). Em ambos os grupos, foi realizada a administração de adrenalina, na dose inicial de 10 ug/Kg, adicionando-se 5 ug/Kg, a cada 5 minutos, até a dose final de 40 ug/Kg. Realizou-se eletrocardiograma em monitorização contínua, comparando-se o número de registros de alterações em ambos os grupos. Observou-se que as principais alterações produzidas pela adrenalina foram ocorrência de bloqueio átrio-ventricular de 2º grau (BAV2) (G1: 92,3% e G2: 100%) e bradicardia (G1: 69,2% e G2: 92,3%) nos 2 grupos. Em menor frequência, verificou-se ocorrência de taquicardia ventricular (TV) não sustentada (G1: 7,7% e G2: 23,1%), extra-sístoles (ES) isoladas (G1: 92,3% - 14,5±11,7 e G2:100% - 24,9±13,9) (p<0,05) e complexos atriais prematuros (CAP) (G1: 92,3% - 5,6±7,2 e G2: 84,6% - 9,5±12,5). Durante os episódios de BAV2 e bradicardia, foi avaliado o tempo (em segundos) para restauração da frequência cardíaca a níveis fisiológicos (G1: 137,3±117,4 e G2: 253,5±151,1) (p<0,05). Conclui-se que a acupuntura é eficaz em reduzir ocorrências de ES, além de atenuar os efeitos do reflexo de Bezold-Jarisch, sendo capaz de retardar a ocorrência de BAV2 e bradicardia e reduzir o tempo de recuperação para ritmo fisiológico, mostrando-se como ferramenta promissora na prevenção de arritmias cardíacas.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2006. / Härtill 4 uppsatser.

INTRODUÇÃO: Muitos procedimentos cirúrgicos e endoscópicos bariátricos realizados atualmente diminuem o volume da luz gástrica de forma isolada ou associados a intervenção sobre o intestino. Uma forma de invaginação ou plicatura gástrica associada ao envolvimento protético do estômago foi usada para tratamento cirúrgico da obesidade. O procedimento foi abandonado devido à elevada taxa de complicações e re-intervenções causadas pelo contato da prótese com as vísceras abdominais. A fundoplicatura a Nissen usada para tratamento de refluxo gastroesofágico leva a emagrecimento pequeno, mas significativo. Na fundoplicatura a Nissen não são usados (e, portanto, não há complicações relacionadas a) secção, grampeamento, anastomose, bandas, anéis ou corpos estranhos. Neste trabalho formulamos a hipótese que a invaginação da grande curvatura gástrica levaria a perda de peso em ratos (Série A - primeira série de experimentos). Confirmada esta hipótese, testamos se a invaginação da parede gástrica anterior teria efeito semelhante (Série B - segunda série de experimentos). A invaginação da parede gástrica anterior evitaria a mobilização do grande omento. MÉTODO: Na Série A, trinta ratos foram sorteados em três grupos. Os dez ratos do primeiro grupo, chamado ACTR- ANEST, foram anestesiados e pesados. Aos dez ratos do segundo grupo, chamado A-CTR-LAP, foram adicionadas laparotomia e manipulação visceral à anestesia. Ao terceiro grupo, chamado A-INV-CURV, foi adicionada uma invaginação da grande curvatura gástrica à anestesia e laparotomia. Os animais da Série A foram pesados novamente no sétimo dia após os procedimentos; pesados, sacrificados e necropsiados no vigésimo - primeiro dia após os procedimentos. Na segunda série de experimentos (Série B), vinte ratos foram sorteados em dois grupos. A parede gástrica anterior foi invaginada em dez ratos no primeiro grupo (B-INV-ANT). A grande curvatura gástrica foi invaginada em dez ratos no segundo grupo (B-INV-CURV). Nesta Série B, os ratos foram pesados semanalmente por quatro semanas, sacrificados e necropsiados no vigésimo - oitavo dia após os procedimentos. RESULTADOS: Na Série A, a média de pesos corporais do grupo A-INV-CURV (311,41g) tornou-se menor que a dos grupos A-CTR-LAP (346,18g) e A-CTR-ANEST (362,48), p<0,001 (ANOVA medidas repetidas). A média de pesos das gorduras peri-testiculares foi significativamente diferente somente entre os grupos A-INV-CURV (4364mg) e A-CTR-ANEST (5059mg), p<0,02 (teste de Dunn). Na Série B, a média de pesos corporais do grupo B-INV-CURV (341,90g) tornou-se menor que a do grupo B-INV-ANT (370,56g) no vigésimo - primeiro dia após os procedimentos, p<0,03 (ajuste de Tukey). Os pesos das gorduras peri-testiculares e os volumes gástricos luminais não foram diferentes no vigésimo - oitavo dia após os procedimentos (sacrifício). CONCLUSÃO: A invaginação da grande curvatura gástrica leva a redução de peso em ratos quando comparada a anestesia isolada, a anestesia seguida de laparotomia, e a invaginação da parede gástrica anterior. / BACKGROUND: Many bariatric endoscopic or surgical procedures performed today reduce gastric luminal volume, alone or in combination with a distal enteric intervention. A form of prosthetic wrap of the folded (or plicated) stomach was used in the past for treating obesity with a high rate of prosthesis-related reintervention. Nissen gastric fundoplication used in the treatment of gastroesophageal reflux disease induces a small but significant weight loss without gastric stapling, partitioning, or prosthesis-related morbidity. We hypothesized greater gastric curvature invagination would lead to weight loss in rats (first series of experiments named Set A). Once confirmed this hypothesis, we compared anterior gastric wall and greater gastric curvature invaginations for weight loss (second series of experiments - Set B). The anterior invagination would be technically easier as it would avoid mobilization of the greater omentum. METHODS: In Set A, 30 rats were randomly divided into 3 groups. 10 rats in the first group (A-CTRANEST) were anesthetized and weighed. The rats from the second group (ACTR- LAP) were in addition submitted to a laparotomy plus visceral manipulation. In the third group (A-INV-CURV), invagination of the greater curvature of the stomach was added. All animals were weighed on the 7th and 21st days. They were then autopsied on the 21st day. In Set B, 20 rats were randomized in 2 groups. The anterior gastric wall of 10 rats was invaginated in the first group (B-INV-ANT). The greater gastric curvature of 10 rats was invaginated in the second group (B-INV-CURV). All animals were weighed weekly for 4 weeks. They were then autopsied on the 28th day. RESULTS: In Set A, the mean body weight of the A-INV-CURV (311,41g) group became less than the A-CTR-LAP (346,18g) and A-CTR-ANEST (362,48) groups, p<0,001 (repeated measures ANOVA). The mean weight of the peritesticular fat pad from the A-INV-CURV group (4364mg) was also significantly less than from the A-CTR-ANEST group (5059mg), p<0,02 (Dunn test), the other peritesticular fat comparisons were indifferent. In Set B, the mean body weight of the B-INV-CURV group (341,90g) became less than the B-INV-ANT group (370,56g) at 21 days, p<0,03 (Tukeys adjustment). The mean weight of the peritesticular fat pad and the mean gastric volume were not different at 28 days (sacrifice). CONCLUSION: Greater gastric curvature invagination (plication) significantly reduces weight compared to isolated anesthesia, to anesthesia and laparotomy, and to anterior gastric wall invagination.

INTRODUÇÃO: Muitos procedimentos cirúrgicos e endoscópicos bariátricos realizados atualmente diminuem o volume da luz gástrica de forma isolada ou associados a intervenção sobre o intestino. Uma forma de invaginação ou plicatura gástrica associada ao envolvimento protético do estômago foi usada para tratamento cirúrgico da obesidade. O procedimento foi abandonado devido à elevada taxa de complicações e re-intervenções causadas pelo contato da prótese com as vísceras abdominais. A fundoplicatura a Nissen usada para tratamento de refluxo gastroesofágico leva a emagrecimento pequeno, mas significativo. Na fundoplicatura a Nissen não são usados (e, portanto, não há complicações relacionadas a) secção, grampeamento, anastomose, bandas, anéis ou corpos estranhos. Neste trabalho formulamos a hipótese que a invaginação da grande curvatura gástrica levaria a perda de peso em ratos (Série A - primeira série de experimentos). Confirmada esta hipótese, testamos se a invaginação da parede gástrica anterior teria efeito semelhante (Série B - segunda série de experimentos). A invaginação da parede gástrica anterior evitaria a mobilização do grande omento. MÉTODO: Na Série A, trinta ratos foram sorteados em três grupos. Os dez ratos do primeiro grupo, chamado ACTR- ANEST, foram anestesiados e pesados. Aos dez ratos do segundo grupo, chamado A-CTR-LAP, foram adicionadas laparotomia e manipulação visceral à anestesia. Ao terceiro grupo, chamado A-INV-CURV, foi adicionada uma invaginação da grande curvatura gástrica à anestesia e laparotomia. Os animais da Série A foram pesados novamente no sétimo dia após os procedimentos; pesados, sacrificados e necropsiados no vigésimo - primeiro dia após os procedimentos. Na segunda série de experimentos (Série B), vinte ratos foram sorteados em dois grupos. A parede gástrica anterior foi invaginada em dez ratos no primeiro grupo (B-INV-ANT). A grande curvatura gástrica foi invaginada em dez ratos no segundo grupo (B-INV-CURV). Nesta Série B, os ratos foram pesados semanalmente por quatro semanas, sacrificados e necropsiados no vigésimo - oitavo dia após os procedimentos. RESULTADOS: Na Série A, a média de pesos corporais do grupo A-INV-CURV (311,41g) tornou-se menor que a dos grupos A-CTR-LAP (346,18g) e A-CTR-ANEST (362,48), p<0,001 (ANOVA medidas repetidas). A média de pesos das gorduras peri-testiculares foi significativamente diferente somente entre os grupos A-INV-CURV (4364mg) e A-CTR-ANEST (5059mg), p<0,02 (teste de Dunn). Na Série B, a média de pesos corporais do grupo B-INV-CURV (341,90g) tornou-se menor que a do grupo B-INV-ANT (370,56g) no vigésimo - primeiro dia após os procedimentos, p<0,03 (ajuste de Tukey). Os pesos das gorduras peri-testiculares e os volumes gástricos luminais não foram diferentes no vigésimo - oitavo dia após os procedimentos (sacrifício). CONCLUSÃO: A invaginação da grande curvatura gástrica leva a redução de peso em ratos quando comparada a anestesia isolada, a anestesia seguida de laparotomia, e a invaginação da parede gástrica anterior. / BACKGROUND: Many bariatric endoscopic or surgical procedures performed today reduce gastric luminal volume, alone or in combination with a distal enteric intervention. A form of prosthetic wrap of the folded (or plicated) stomach was used in the past for treating obesity with a high rate of prosthesis-related reintervention. Nissen gastric fundoplication used in the treatment of gastroesophageal reflux disease induces a small but significant weight loss without gastric stapling, partitioning, or prosthesis-related morbidity. We hypothesized greater gastric curvature invagination would lead to weight loss in rats (first series of experiments named Set A). Once confirmed this hypothesis, we compared anterior gastric wall and greater gastric curvature invaginations for weight loss (second series of experiments - Set B). The anterior invagination would be technically easier as it would avoid mobilization of the greater omentum. METHODS: In Set A, 30 rats were randomly divided into 3 groups. 10 rats in the first group (A-CTRANEST) were anesthetized and weighed. The rats from the second group (ACTR- LAP) were in addition submitted to a laparotomy plus visceral manipulation. In the third group (A-INV-CURV), invagination of the greater curvature of the stomach was added. All animals were weighed on the 7th and 21st days. They were then autopsied on the 21st day. In Set B, 20 rats were randomized in 2 groups. The anterior gastric wall of 10 rats was invaginated in the first group (B-INV-ANT). The greater gastric curvature of 10 rats was invaginated in the second group (B-INV-CURV). All animals were weighed weekly for 4 weeks. They were then autopsied on the 28th day. RESULTS: In Set A, the mean body weight of the A-INV-CURV (311,41g) group became less than the A-CTR-LAP (346,18g) and A-CTR-ANEST (362,48) groups, p<0,001 (repeated measures ANOVA). The mean weight of the peritesticular fat pad from the A-INV-CURV group (4364mg) was also significantly less than from the A-CTR-ANEST group (5059mg), p<0,02 (Dunn test), the other peritesticular fat comparisons were indifferent. In Set B, the mean body weight of the B-INV-CURV group (341,90g) became less than the B-INV-ANT group (370,56g) at 21 days, p<0,03 (Tukeys adjustment). The mean weight of the peritesticular fat pad and the mean gastric volume were not different at 28 days (sacrifice). CONCLUSION: Greater gastric curvature invagination (plication) significantly reduces weight compared to isolated anesthesia, to anesthesia and laparotomy, and to anterior gastric wall invagination.