Objective: To assess effects of bisection nephrotomy on renal function, size, and morphology in cats over a period of 12 weeks. Study Design: Controlled, randomized, blinded experiment. Sample Population: Ten adult female cats. Methods: Glomerular filtration rate (GFR), as determined by quantitative renal scintigraphy using 99mTc-DTPA, urinalysis, urine culture, and sonographic measurement of renal size were performed pre-operatively. A left or right nephrotomy (five randomly assigned cats in each group) was performed. Total and individual kidney GFRs were determined in each cat 2, 28 and 84 days post-operatively. Both kidneys were measured sonographically 28 and 86 days postoperatively and an ultrasound-guided biopsy of each kidney was obtained 86 days postoperatively. Results: No significant differences in mean GFR and kidney size of the operated versus un-operated kidneys were observed at any time period. Individual GFR and renal size of all except one of the cats remained within normal limits. Two additional cats had evidence of transient ureteral obstruction in the immediate post-operative period. No significant histologic abnormalities were observed in any biopsy. Conclusions: Bisection nephrotomy in normal cats did not adversely affect renal function or morphology over the three month post-operative period. Clinical Relevance: Bisection nephrotomy can be safely performed in normal feline kidneys without causing a significant deleterious effect on renal function. Studies in animals with pre-existing renal insufficiency are needed to insure no adverse effects would occur in clinical cases where this surgical procedure is warranted. / Master of Science

Electrophoresis is the technique used to characterize proteins, oligonucleotides, and DNA. Methods employed to date include gel and capillary electrophoresis. Most samples can be characterized by these methods. However, large DNA molecules do not separate well with either method. A newer electrophoresis method involves the use of the Doppler effect to determine a particle’s characteristics. This thesis is concerned with the design and development of an open geometry Doppler electrophoresis instrument for macromolecular characterization in solution where gel characteristics and electroosmotic flow need not be considered. / Master of Science

O objetivo do presente trabalho foi avaliar o valor diagnóstico e o impacto na modificação da conduta terapêutica do ultra-som intra-operatório (UIO) na cirurgia por neoplasia de fígado, vias biliares e pâncreas, comparando-se achados da avaliação pré-operatória de rotina com métodos de imagem convencionais (tomografia computadorizada e ressonância magnética) com achados obtidos por meio da exploração cirúrgica (inspeção e palpação). Foram analisados, retrospectivamente, exames realizados em 49 pacientes, sendo 15 portadores de neoplasia hepática secundária; 14, de neoplasia hepática primária; 14, de tumor neuroendócrino pancreático e seis de neoplasia cística pancreática. No grupo de pacientes com neoplasia hepática e de vias biliares, a TC identificou 65% dos tumores; a exploração cirúrgica, 69,5% e o UIO, 95,2%. Houve mudança da conduta, em decorrência dos achados do UIO, em 34,4% dos pacientes. No grupo de tumores neuroendócrinos pancreáticos, a TC identificou corretamente 44,4% dos tumores; a RM, 60,9%; a exploração cirúrgica com palpação, 72,7% e o UIO, 100%. Houve mudança de conduta em 42,9% dos pacientes. No grupo de neoplasia cística, o UIO não acrescentou informação adicional relevante em relação à TC e à RM, exceto no paciente com neoplasia papilífera intraductal. Apesar do grande avanço nos métodos de avaliação por imagem pré-operatórios e mesmo com toda a expertise do cirurgião, os resultados mostram que o UIO modifica positivamente o planejamento cirúrgico em um número significativo de pacientes, devendo, portanto fazer parte integrante da avaliação intra-operatória dos pacientes candidatos à ressecção hepática por neoplasia primária ou secundária e da cirurgia de neoplasia endócrina pancreática / Intraoperative sonography (IOU) is an imaging modality that has been showing rapid growth in the last decade that can has a variety of applications in different surgical specialities, particularly in abdominal surgery. The purpose of this study was to analyze the use o IOU in the setting of surgery for liver, biliary and pancreatic malignancies. To achieve that, the findings of routine preoperative state-of the-art imaging modalities (CT and MRI) and the findings of surgical exploration (inspection and palpation) were compared to those of IOU. The impact of IOU on preoperative plans based on CT and MRI and on management after surgical exploration were studied as well 49 patients were retrospectively studied. Of those 15 had metastatic liver disease and 14 primary liver cancer; 14 had pancreatic neuroendocrine tumours and 6 had cystic pancreatic neoplasms. In the group of hepatic and biliary malignancies CT identified 65% of the tumours, surgical exploration identified 69.5% and IOU 95.2% (including 3 false positives). IOU determined a change in management in 34.4% of the patients. In the group of pancreatic neuroendocrine tumours the rates of identification were 27.3% for CT, 60.9% for MRI, 72.7% for surgical exploration and 100% for IOU, with an alteration in surgical plans in 42.9% of patients after IOU. In the case of patients with cystic pancreatic neoplasia, IOUS did not add any relevant additional information in relation to CT or MRI, with exception to one patient that had a papiliferous intraductal neoplasia. In spite of the great advances on preoperatory imaging modalities and of the possibility of direct surgical exploration, IOU has shown that it positively modifies surgical planning. For that reason, it should be included as an essential adjunct in the intraoperatory evaluation of patients with pancreatic endocrine neoplasia and of candidates for hepatic resection in cases of primary and secondary malignancies

INTRODUÇÃO: O duplex-Doppler e a ultrassonografia com contraste são métodos pouco estudados em lesões mamárias. No entanto, em outros órgãos, têm se mostrado úteis na distinção entre lesões benignas e malignas. O objetivo deste trabalho é caracterizar os achados ao Doppler colorido pré e pós-contraste nos nódulos sólidos de mama, correlacionando-os com os resultados anatomopatológicos. MATERIAL E MÉTODOS: Setenta nódulos sólidos da mama foram avaliados por meio de ultrassonografia convencional e duplex-Doppler colorido antes e após a injeção do meio de contraste (ultrassonografia contrastada), no período compreendido entre março de 2007 e janeiro de 2008, e seus resultados foram comparados à análise histológica (padrão-ouro). Todas as pacientes assinaram o Termo de Consentimento Livre e Esclarecido, aprovado pelo Comitê de Ética da FMUSP. O estudo ultrassonográfico modo B avaliou a morfologia do nódulo e o classificou conforme o léxico BI-RADS. Ao duplex-Doppler colorido observou-se a vascularização nodular, descrevendo-se o número de vasos presentes (0 = avascularizado; 1 ou 2 = hipovascularizado, 3 = hipervascularizado), sua morfologia (regular ou tortuoso) e sua distribuição (periférica ou central). Os índices de resistividade e a presença de vaso penetrante também foram avaliados. A partir de dados da literatura criou-se um critério de classificação que permitiu estratificá-los entre provavelmente benigno (nódulos avasculares ou hipovasculares, com vasos regulares e distribuição periférica), provavelmente maligno (nódulos hipervasculares, com vasos tortuosos e distribuição central) ou suspeitos (qualquer outra associação desses fatores). No estudo contrastado foram realizadas análises cinética (avaliando-se os tempos de início da contrastação e do clareamento do nódulo, além da análise da intensidade da contrastação, de maneira subjetiva) e morfológica (utilizando-se os mesmos critérios da análise com Doppler). RESULTADOS: A análise histológica resultou em 25 lesões malignas e 45 lesões benignas. A classificação BI-RADS teve sensibilidade de 100%, especificidade de 66,6%, valor preditivo positivo (VPP) de 62,5% e valor preditivo negativo (VPN) de 100%. A análise com Doppler mostrou sensibilidade de 88%, especificidade de 57,7%, VPP de 53,6% e VPN de 89,9%. Após a injeção do meio de contraste, esses valores passaram para: 92%, 46,6%, 48% e 91%, respectivamente. Os índices de resistividade foram significativamente mais altos em lesões malignas na análise com Doppler colorido ( < 0,001). Houve relação estatística significante entre a presença de vaso penetrante e malignidade ( < 0,001). A associação entre os critérios de classificação BI-RADS e Doppler colorido mostrou sensibilidade de 100%, especificidade de 86,6%, VPP de 80,7% e VPN de 100%. A associação entre BI-RADS e ultrassonografia contrastada resultou em sensibilidade de 100%, especificidade de 80%, VPP de 73,5% e VPN de 100%. A análise cinética subjetiva não conseguiu diferenciar entre nódulo benigno e maligno (tempo do início da contrastação = 0,816, tempo de clareamento da lesão = 0,622 e realce da lesão = 0,020). CONCLUSÃO: Os critérios adotados para o duplex-Doppler colorido associados ao BI-RADS fornecem os melhores resultados na distinção entre lesões benignas e malignas da mama. O estudo contrastado não acrescentou informações adicionais às análises prévias. / OBJECTIVE: The duplex-Doppler ultrasound and contrast enhanced ultrasound (CEUS) are poorly studied in breast lesions. However, in the other organs they have been proved to be useful in mass differentiation. Our objective is to characterize the Doppler findings before and after contrast agent injection in solid breast lesions then correlate them with pathological findings in order to evaluate the applicability of these methods in the differentiation of benign and malignant lesions. MATERIALS AND METHODS: Seventy solid breast masses were evaluated by conventional ultrasonography and duplex-color Doppler before and after injection of contrast medium (ultrasound contrast) in the period between March 2007 and January 2008 and their results were compared to histology (gold standard). All patients signed a consent form approved by the Ethics Committee of FMUSP. At gray-scale US the lesions were described and classified according to the BI-RADS lexicon. At duplex-Doppler we observed the lesion vascularity: avascular, hypovascular (one or two arteries) or hypervascular (three or more arteries); distribution (central or peripheral) and shape (regular or tortuous). If there was a penetrating artery, it was reported. We also observed resistive index. Based on literature data criterion was set up for classification which allowed to stratify breast lesions among probably benign (avascular or hypovascular masses, with regular vessels and peripheral distribution); probably malignant (hypervascular masses with tortuous and central vessels) or suspicious (any other combination of those factors). Kinetic analysis (wash in and wash out times, besides mass enhancement, in a subjective manner) and morphological analysis (using the same criteria of analysis with Doppler) were described in contrast study. RESULTS: Percutaneous biopsy revealed 25 malignant and 45 benign lesions. Morphologic analysis using gray-scale sonography and classified according the BI-RADS lexico showed sensitivity of 100% and specificity of 66.6%, positive and negative predictive values of 62.5% and 100% respectively. Doppler sonography, sensitivity, specificity, positive and negative predictive values were 88%; 57.7%; 53.6% and 89.9%. After contrast agent injection sensitivity, specificity, positive and negative predictive values changed to 92%; 46.6%; 48% and 91% respectively. The association among morphological and CDUS analysis findings resulted in a sensitivity of 100%, specificity of 86.6%, PPV 80.7% and NPV 100%. When morphological findings and CEUS analysis were associated values became 100% sensitivity, 80% specificity, 73.5% PPV, and 100% NPV. Resistive index was significantly higher ( < 0,001) in malignant lesions before and after contrast injection. Wash in and wash out times were similar for benign and malignant lesions (wash-in = 0,816, wash-out = 0,622 and intensity = 0,020). CONCLUSION: Duplex-Doppler criteria associated to BI-RADS classification proved to be the best combination to distinguish malignant lesions of the breast. CEUS evaluation did not provide additional information.

Wong Chi Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 74-94). / Abstracts in English and Chinese. / Tittle / Table of contents / Acknowledgment / Abstract / Chapter Chapter 1. --- Introduction --- p.1 / Chapter Chapter 2. --- Literature Reviews --- p.2 / Chapter 2.1 --- Sonographic history --- p.2 / Chapter 2.1.1 --- Definition of ultrasound --- p.2 / Chapter 2.1.2 --- History of general ultrasonography --- p.2 / Chapter 2.1.3 --- Early history of fetal diagnostic ultrasonography --- p.4 / Chapter 2.2 --- Placental sonography --- p.10 / Chapter 2.2.1 --- Development of the placenta --- p.10 / Chapter 2.2.2 --- Sonographic placental development --- p.12 / Chapter 2.2.3 --- Placental grading --- p.14 / Chapter 2.2.3.1 --- Early studies of the placenta --- p.14 / Chapter 2.2.3.2 --- Placental grading --- p.16 / Chapter 2.2.3.3 --- Placental grading and gestational age --- p.18 / Chapter 2.2.3.4 --- Placental grade and neonatal outcome --- p.20 / Chapter 2.2.4 --- Placental thickness --- p.22 / Chapter 2.3 --- Amniotic fluid --- p.24 / Chapter 2.3.1 --- Amniotic fluid dynamics --- p.24 / Chapter 2.3.2 --- Methods of sonographic assessment of amniotic fluid --- p.28 / Chapter 2.3.3 --- Correlation of AFI with clinical oligohydramnios --- p.30 / Chapter 2.3.4 --- Clinical outcome associated with oligohydramnios --- p.32 / Chapter Chapter 3. --- Methodology --- p.34 / Chapter 3.1 --- Introduction --- p.34 / Chapter 3.2 --- Criteria for patients selection --- p.35 / Chapter 3.3 --- Calculation of the gestational age --- p.35 / Chapter 3.3.1 --- Measurement of bipatietal diameter (BPD) --- p.36 / Chapter 3.4 --- Ultrasonic measurements of the placenta and amniotic fluid --- p.37 / Chapter 3.4.1 --- Placental grading --- p.37 / Chapter 3.4.2 --- Placental thickness --- p.38 / Chapter 3.4.3 --- Amniotic fluid index --- p.39 / Chapter 3.5 --- Statistical analysis --- p.39 / Chapter 3.5.1 --- Amniotic fluid index --- p.39 / Chapter 3.5.2 --- Placental thickness --- p.40 / Chapter 3.5.3 --- Clinical outcome --- p.41 / Chapter Chapter 4. --- Results --- p.42 / Chapter 4.1 --- Overall obstetric demographic characteristics of study population --- p.44 / Chapter 4.2 --- "Gestation-related changes in placental grade, placental thickness and amniotic fluid index" --- p.48 / Chapter 4.2.1 --- "Amniotic fluid index, gestational age and maternal characteristics" --- p.48 / Chapter 4.2.2 --- Placental thickness --- p.53 / Chapter 4.2.3 --- Placental grades and gestational age --- p.57 / Chapter 4.3 --- The clinical outcomes and ultrasound parameters --- p.61 / Chapter Chapter 5. --- Discussion --- p.63 / Chapter 5.1 --- Gestation related change of AFI and maternal characteristics --- p.63 / Chapter 5.2 --- Placental grade and gestational age --- p.67 / Chapter 5.3 --- Placental thickness --- p.72 / Chapter Chapter 6. --- Reference --- p.74 / Graphics --- p.95 / Figure 1 Grannum's placental grading system / Figure 2 Amniotic fluid index against gestational age / Figure 3 Placental thickness versus gestational age / Figure 4 Graph of placental grades versus progressing gestational age / Figure 5 Median amniotic fluid index in four populations

INTRODUÇÃO: O duplex-Doppler e a ultrassonografia com contraste são métodos pouco estudados em lesões mamárias. No entanto, em outros órgãos, têm se mostrado úteis na distinção entre lesões benignas e malignas. O objetivo deste trabalho é caracterizar os achados ao Doppler colorido pré e pós-contraste nos nódulos sólidos de mama, correlacionando-os com os resultados anatomopatológicos. MATERIAL E MÉTODOS: Setenta nódulos sólidos da mama foram avaliados por meio de ultrassonografia convencional e duplex-Doppler colorido antes e após a injeção do meio de contraste (ultrassonografia contrastada), no período compreendido entre março de 2007 e janeiro de 2008, e seus resultados foram comparados à análise histológica (padrão-ouro). Todas as pacientes assinaram o Termo de Consentimento Livre e Esclarecido, aprovado pelo Comitê de Ética da FMUSP. O estudo ultrassonográfico modo B avaliou a morfologia do nódulo e o classificou conforme o léxico BI-RADS. Ao duplex-Doppler colorido observou-se a vascularização nodular, descrevendo-se o número de vasos presentes (0 = avascularizado; 1 ou 2 = hipovascularizado, 3 = hipervascularizado), sua morfologia (regular ou tortuoso) e sua distribuição (periférica ou central). Os índices de resistividade e a presença de vaso penetrante também foram avaliados. A partir de dados da literatura criou-se um critério de classificação que permitiu estratificá-los entre provavelmente benigno (nódulos avasculares ou hipovasculares, com vasos regulares e distribuição periférica), provavelmente maligno (nódulos hipervasculares, com vasos tortuosos e distribuição central) ou suspeitos (qualquer outra associação desses fatores). No estudo contrastado foram realizadas análises cinética (avaliando-se os tempos de início da contrastação e do clareamento do nódulo, além da análise da intensidade da contrastação, de maneira subjetiva) e morfológica (utilizando-se os mesmos critérios da análise com Doppler). RESULTADOS: A análise histológica resultou em 25 lesões malignas e 45 lesões benignas. A classificação BI-RADS teve sensibilidade de 100%, especificidade de 66,6%, valor preditivo positivo (VPP) de 62,5% e valor preditivo negativo (VPN) de 100%. A análise com Doppler mostrou sensibilidade de 88%, especificidade de 57,7%, VPP de 53,6% e VPN de 89,9%. Após a injeção do meio de contraste, esses valores passaram para: 92%, 46,6%, 48% e 91%, respectivamente. Os índices de resistividade foram significativamente mais altos em lesões malignas na análise com Doppler colorido ( < 0,001). Houve relação estatística significante entre a presença de vaso penetrante e malignidade ( < 0,001). A associação entre os critérios de classificação BI-RADS e Doppler colorido mostrou sensibilidade de 100%, especificidade de 86,6%, VPP de 80,7% e VPN de 100%. A associação entre BI-RADS e ultrassonografia contrastada resultou em sensibilidade de 100%, especificidade de 80%, VPP de 73,5% e VPN de 100%. A análise cinética subjetiva não conseguiu diferenciar entre nódulo benigno e maligno (tempo do início da contrastação = 0,816, tempo de clareamento da lesão = 0,622 e realce da lesão = 0,020). CONCLUSÃO: Os critérios adotados para o duplex-Doppler colorido associados ao BI-RADS fornecem os melhores resultados na distinção entre lesões benignas e malignas da mama. O estudo contrastado não acrescentou informações adicionais às análises prévias. / OBJECTIVE: The duplex-Doppler ultrasound and contrast enhanced ultrasound (CEUS) are poorly studied in breast lesions. However, in the other organs they have been proved to be useful in mass differentiation. Our objective is to characterize the Doppler findings before and after contrast agent injection in solid breast lesions then correlate them with pathological findings in order to evaluate the applicability of these methods in the differentiation of benign and malignant lesions. MATERIALS AND METHODS: Seventy solid breast masses were evaluated by conventional ultrasonography and duplex-color Doppler before and after injection of contrast medium (ultrasound contrast) in the period between March 2007 and January 2008 and their results were compared to histology (gold standard). All patients signed a consent form approved by the Ethics Committee of FMUSP. At gray-scale US the lesions were described and classified according to the BI-RADS lexicon. At duplex-Doppler we observed the lesion vascularity: avascular, hypovascular (one or two arteries) or hypervascular (three or more arteries); distribution (central or peripheral) and shape (regular or tortuous). If there was a penetrating artery, it was reported. We also observed resistive index. Based on literature data criterion was set up for classification which allowed to stratify breast lesions among probably benign (avascular or hypovascular masses, with regular vessels and peripheral distribution); probably malignant (hypervascular masses with tortuous and central vessels) or suspicious (any other combination of those factors). Kinetic analysis (wash in and wash out times, besides mass enhancement, in a subjective manner) and morphological analysis (using the same criteria of analysis with Doppler) were described in contrast study. RESULTS: Percutaneous biopsy revealed 25 malignant and 45 benign lesions. Morphologic analysis using gray-scale sonography and classified according the BI-RADS lexico showed sensitivity of 100% and specificity of 66.6%, positive and negative predictive values of 62.5% and 100% respectively. Doppler sonography, sensitivity, specificity, positive and negative predictive values were 88%; 57.7%; 53.6% and 89.9%. After contrast agent injection sensitivity, specificity, positive and negative predictive values changed to 92%; 46.6%; 48% and 91% respectively. The association among morphological and CDUS analysis findings resulted in a sensitivity of 100%, specificity of 86.6%, PPV 80.7% and NPV 100%. When morphological findings and CEUS analysis were associated values became 100% sensitivity, 80% specificity, 73.5% PPV, and 100% NPV. Resistive index was significantly higher ( < 0,001) in malignant lesions before and after contrast injection. Wash in and wash out times were similar for benign and malignant lesions (wash-in = 0,816, wash-out = 0,622 and intensity = 0,020). CONCLUSION: Duplex-Doppler criteria associated to BI-RADS classification proved to be the best combination to distinguish malignant lesions of the breast. CEUS evaluation did not provide additional information.

Close integration of front-end electronics and the transducer array within the catheter is critical for successful implementation of CMUT-based intravascular ultrasound (IVUS) imaging catheters to enable next generation imaging tools. Therefore, this research developed and implemented custom-designed electronic circuits and systems integrated with an IC compatible transducer technology for realization of miniature IVUS imaging catheters operating at 10-50 MHz frequency range. In one path of this research, an IC is custom designed in a 0.35-um CMOS process to monolithically integrate with a CMUT array (CMUT-on-CMOS) to realize a single-chip, highly-flexible, forward-looking (FL) IVUS imaging system. The amplifiers that are custom-designed achieved transducer thermal-mechanical noise dominated receive performance in a CMUT-on-CMOS implementation. In parallel to the FL-IVUS effort, for realization of a side-looking IVUS catheter based on an annular phased array, a dynamic receive beamformer IC is custom designed also in a 0.35-um CMOS process. Overall, the circuits and systems developed as part of this dissertation form a critical step in the translation of the research on CMUT-based IVUS catheters into real clinical applications for better management of coronary arterial diseases.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 5 uppsatser.

O objetivo do presente trabalho foi avaliar o valor diagnóstico e o impacto na modificação da conduta terapêutica do ultra-som intra-operatório (UIO) na cirurgia por neoplasia de fígado, vias biliares e pâncreas, comparando-se achados da avaliação pré-operatória de rotina com métodos de imagem convencionais (tomografia computadorizada e ressonância magnética) com achados obtidos por meio da exploração cirúrgica (inspeção e palpação). Foram analisados, retrospectivamente, exames realizados em 49 pacientes, sendo 15 portadores de neoplasia hepática secundária; 14, de neoplasia hepática primária; 14, de tumor neuroendócrino pancreático e seis de neoplasia cística pancreática. No grupo de pacientes com neoplasia hepática e de vias biliares, a TC identificou 65% dos tumores; a exploração cirúrgica, 69,5% e o UIO, 95,2%. Houve mudança da conduta, em decorrência dos achados do UIO, em 34,4% dos pacientes. No grupo de tumores neuroendócrinos pancreáticos, a TC identificou corretamente 44,4% dos tumores; a RM, 60,9%; a exploração cirúrgica com palpação, 72,7% e o UIO, 100%. Houve mudança de conduta em 42,9% dos pacientes. No grupo de neoplasia cística, o UIO não acrescentou informação adicional relevante em relação à TC e à RM, exceto no paciente com neoplasia papilífera intraductal. Apesar do grande avanço nos métodos de avaliação por imagem pré-operatórios e mesmo com toda a expertise do cirurgião, os resultados mostram que o UIO modifica positivamente o planejamento cirúrgico em um número significativo de pacientes, devendo, portanto fazer parte integrante da avaliação intra-operatória dos pacientes candidatos à ressecção hepática por neoplasia primária ou secundária e da cirurgia de neoplasia endócrina pancreática / Intraoperative sonography (IOU) is an imaging modality that has been showing rapid growth in the last decade that can has a variety of applications in different surgical specialities, particularly in abdominal surgery. The purpose of this study was to analyze the use o IOU in the setting of surgery for liver, biliary and pancreatic malignancies. To achieve that, the findings of routine preoperative state-of the-art imaging modalities (CT and MRI) and the findings of surgical exploration (inspection and palpation) were compared to those of IOU. The impact of IOU on preoperative plans based on CT and MRI and on management after surgical exploration were studied as well 49 patients were retrospectively studied. Of those 15 had metastatic liver disease and 14 primary liver cancer; 14 had pancreatic neuroendocrine tumours and 6 had cystic pancreatic neoplasms. In the group of hepatic and biliary malignancies CT identified 65% of the tumours, surgical exploration identified 69.5% and IOU 95.2% (including 3 false positives). IOU determined a change in management in 34.4% of the patients. In the group of pancreatic neuroendocrine tumours the rates of identification were 27.3% for CT, 60.9% for MRI, 72.7% for surgical exploration and 100% for IOU, with an alteration in surgical plans in 42.9% of patients after IOU. In the case of patients with cystic pancreatic neoplasia, IOUS did not add any relevant additional information in relation to CT or MRI, with exception to one patient that had a papiliferous intraductal neoplasia. In spite of the great advances on preoperatory imaging modalities and of the possibility of direct surgical exploration, IOU has shown that it positively modifies surgical planning. For that reason, it should be included as an essential adjunct in the intraoperatory evaluation of patients with pancreatic endocrine neoplasia and of candidates for hepatic resection in cases of primary and secondary malignancies

OBJETIVO: Determinar os valores de referência, e examinar a correlação da área de secção transversa do cordão umbilical, e de seus componentes, com a idade gestacional (IG), em gestações gemelares. Examinar a correlação da área de secção transversa do cordão umbilical com o peso fetal estimado (PFE). MATERIAIS E MÉTODOS: Estudo prospectivo longitudinal envolvendo gestações gemelares dicoriônicas, não complicadas. Medidas ultrassonográficas das áreas de secção transversa do cordão umbilical (ASTCU), da veia (AVU) e artérias umbilicais (AAU), e da geleia de Wharton (AGW) foram obtidas em plano adjacente, próximo ao abdômen fetal, a cada três semanas. A correlação entre os parâmetros avaliados e a idade gestacional foi investigada por meio de modelo de regressão polinomial hierárquica, levando-se em consideração a variância segundo a idade gestacional, entre medidas obtidas em fetos da mesma gestação e, entre diferentes gestações. Para cada parâmetro estudado, foram calculados os valores correspondentes aos percentis 5, 10, 50, 90 e 95, para cada semana gestacional. RESULTADOS: Foram realizadas 334 avaliações ultrassonográficas em 44 gestações gemelares, entre 18 e 33 semanas (média: 3,8 ± 0,7 exames/gestação; intervalo médio entre exames: 3,3 ± 0,9 semanas). Os valores log-transformados de todos os parâmetros avaliados apresentaram correlação significativa (p<0,001) com a idade gestacional: Log(ASTCU) = - 2,287498 + 0,149298 x IG - 0,002302 x IG2, desvio-padrão DP = 0,113, R2 = 0,65; Log (AVU) = - 2,721487 + 0,119853 x IG - 0,001507 x IG2, DP=0,165, R2 = 0,58; Log (AAU) = - 4,223546 + 0,195454 x IG - 0,003080 x IG2, DP=0,163, R2 = 0,57; Log (AGW) = - 2,511648 + 0,157737 x IG - 0,002564 x IG2, DP=0,123, R2 = 0,55. A área de secção transversa do cordão umbilical apresentou correlação significativa com o peso fetal estimado (Log (ASTCU) = -1,602447 + 0,554502 x Log (PFE), R2 = 0,65, p < 0,001). CONCLUSÃO: Em gestações gemelares dicoriônicas, a área de secção transversa do cordão umbilical, e de seus componentes, mostram correlação positiva e significativa com a idade gestacional. A área de secção transversa do cordão umbilical também correlaciona-se significativamente com o peso fetal estimado / OBJECTIVE: To determine reference values, and examine the correlation between the cross-sectional area of the umbilical cord, and its components, with gestational age (GA) in twin pregnancies. To examine the correlation between the cross-sectional area of the umbilical cord with the estimated fetal weight (EFW). MATERIALS AND METHODS: A prospective longitudinal study involving uncomplicated dichorionic twin pregnancies. Sonographic measurements of the cross-sectional areas of the umbilical cord (UCCSA), umbilical vein (UVA) and arteries (UAA) and Wharton\'s jelly (WGA) were obtained in a plane adjacent to the fetal abdomen, every three weeks. The correlation between these parameters and gestational age was examined with hierarchical polynomial regression analysis. This modeling took into account the variance according to gestational age, fetuses within the same pregnancy and changes across different pregnancies. For each parameter, 5th, 10th, 50th, 90th and 95th centiles were calculated for each gestational week. RESULTS: 334 ultrasound scans were performed in 44 twin pregnancies, between 18 and 33 weeks (mean: 3.8 ± 0.7 scans/pregnancy, mean interval between scans: 3.3 ± 0.9 weeks). All umbilical cord log-transformed values showed a significant correlation (p < 0.001) with gestational age: Log (UCCSA) = - 2.287498 + 0.149298 x GA - 0.002302 x IG2, SD = standard deviation 0.113, R2 = 0.65, Log (UVA) = - 2.721487 + 0.119853 x GA - 0.001507 x IG2, SD = 0.165, R2 = 0.58, Log (UAA) = - 4.223546 + IG x 0.195454 - 0.003080 x IG2, SD = 0.163, R2 = 0.57, Log (WGA) = - 2.511648 + 0.157737 x GA - 0.002564 x IG2 , SD = 0.123, R2 = 0.55. The cross-sectional area of the umbilical cord also correlated significantly with the estimated fetal weight (Log (UCCSA) = -1.602447 + 0.554502 x Log (EFW), R2 = 0.65, p < 0.001). CONCLUSION: In dichorionic twin pregnancies, the cross-sectional areas of the umbilical cord, and its components, show a positive and significant correlation with gestational age. The cross-sectional area of the umbilical cord also has correlates significantly with the estimated fetal weight