12 research outputs found
Non-invasive detection of biliary leaks using Gd-EOB-DTPA-enhanced MR cholangiography: Comparison with T2-weighted MR cholangiography
No full textObjective: To evaluate the added role of T1-weighted (T1w) gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance cholangiography (MRC) compared with T2-weighted MRC (T2w-MRC) in the detection of biliary leaks. Methods: Ninety-nine patients with suspected biliary complications underwent routine T2w-MRC and T1w contrast-enhanced (CE) MRC using Gd-EOB-DTPA to identify biliary leaks. Two observers reviewed the image sets separately and together. MRC findings were compared with those of surgery and percutaneous transhepatic cholangiopancreatography. The sensitivity, specificity and accuracy of the techniques in identifying biliary leaks were calculated. Results: Accuracy of locating biliary leaks was superior with the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC (P 0.05).The mean sensitivities were 79 % vs 59 %, and the mean accuracy rates were 84 % vs 58 % for combined CE-MRC and T2w-MRC vs sole T2w-MRC. Nineteen out of 21 patients with biliary-cyst communication, 90.4 %, and 12/15 patients with post-traumatic biliary extravasations, 80 %, were detected by the combination of Gd-EOB-DTPA-enhanced MRC and T2w-MRC images, P 0.05. Conclusions: Gd-EOB-DTPA-enhanced MRC yields information that complements T2w-MRC findings and improves the identification and localisation of the bile extravasations (84 % accuracy, 100 % specificity, P 0.05). We recommend Gd-EOB-DTPA-enhanced MRC in addition to T2w-MRC to increase the preoperative accuracy of identifying and locating extravasations of bile. Key Points: • Magnetic resonance cholangiography (MRC) does not always detect bile leakage and cysto-biliary communications. • Gd-EOB-DTPA-enhanced MRC helps by demonstrating extravasation of contrast material into fluid collections. • Gd-EOB-DTPA-enhanced MRC also demonstrates the leakage site and bile duct injury type. • Combined Gd-EOB-DTPA-enhanced and T2w-MRC can provide comprehensive information about biliary system. • Gd-EOB-DTPA-enhanced MRC is non-invasive and does not use ionising radiation. © 2013 The Author(s)
Comparison between dynamic gadoxetate-enhanced MRI and <sup>99m</sup> Tc-mebrofenin hepatobiliary scintigraphy with SPECT for quantitative assessment of liver function
No full text Objectives: To compare Gd-EOB-DTPA dynamic hepatocyte-specific contrast-enhanced MRI (DHCE-MRI) with 99m Tc-mebrofenin hepatobiliary scintigraphy (HBS) as quantitative liver function tests for the preoperative assessment of patients undergoing liver resection. Methods: Patients undergoing liver surgery and preoperative assessment of future remnant liver (FRL) function using 99m Tc-mebrofenin HBS were included. Patients underwent DHCE-MRI. Total liver uptake function was calculated for both modalities: mebrofenin uptake rate (MUR) and Ki respectively. The FRL was delineated with both SPECT-CT and MRI to calculate the functional share. Blood samples were taken to assess biochemical liver parameters. Results: A total of 20 patients were included. The HBS-derived MUR and the DHCE-MRI-derived mean Ki correlated strongly for both total and FRL function (Pearson r = 0.70, p = 0.001 and r = 0.89, p < 0.001 respectively). There was a strong agreement between the functional share determined with both modalities (ICC = 0.944, 95% CI 0.863–0.978, n = 20). There was a significant negative correlation between liver aminotransferases and bilirubin for both MUR and Ki. Conclusions: Assessment of liver function with DHCE-MRI is comparable with that of 99m Tc-mebrofenin HBS and has the potential to be combined with diagnostic MRI imaging. This can therefore provide a one-stop-shop modality for the preoperative assessment of patients undergoing liver surgery. Key Points: • Quantitative assessment of liver function using hepatobiliary scintigraphy is performed in the preoperative assessment of patients undergoing liver surgery in order to prevent posthepatectomy liver failure. • Gd-EOB-DTPA dynamic hepatocyte-specific contrast-enhanced MRI (DHCE-MRI) is an emerging method to quantify liver function and can serve as a potential alternative to hepatobiliary scintigraphy. • Assessment of liver function with dynamic gadoxetate-enhanced MRI is comparable with that of hepatobiliary scintigraphy and has the potential to be combined with diagnostic MRI imaging. ImPhys/Quantitative ImagingApplied Science
Precisión Diagnóstica del Gadolinio vs. Contraste Hepatoespecífico en la Caracterización de Lesiones Hepáticas Focales en Resonancia Magnética: Una Revisión Sistemática
No full textMagnetic resonance imaging (MRI) is a highly resolving imaging technique that has become an essential tool for liver evaluation, especially in the diagnosis of focal liver lesions. The use of contrast agents, particularly gadolinium and liver-specific contrast agents, plays a crucial role in improving diagnostic accuracy. Methodology: A systematic review evaluating the diagnostic accuracy of contrast agents in identifying liver conditions focused on research published between 2020 and 2025. Databases such as PubMed, ScienceDirect, and Scielo were used. Original articles and relevant reviews were included, excluding pediatric and non-peer-reviewed studies. Results: The use of gadolinium and liver-specific contrast agents, especially Gd-EOB-DTPA, has proven to be a fundamental tool in MRI for the diagnosis and management of liver lesions. Conclusion: Both types of contrast agents, gadolinium and liver-specific contrast agents, have advantages and limitations in the evaluation of liver lesions. The choice of the appropriate contrast agent must consider the nature of the lesions, the patient's liver status, and the diagnostic objectives. Although gadolinium is useful in clinical practice, liver-specific contrast agents such as Gd-EOB-DTPA and Gd-BOPTA offer additional benefits that improve the diagnosis of focal liver lesions and optimize the management of liver disease.La resonancia magnética (RM) es una técnica de imagen altamente resolutiva que se ha convertido en una herramienta esencial para la evaluación del hígado, especialmente en el diagnóstico de lesiones hepáticas focales. La utilización de agentes de contraste, en particular el gadolinio y los contrastes hepatospecíficos, juega un papel crucial en la mejora de la precisión diagnóstica. Metodología: Revisión sistemática que evalúa la precisión diagnóstica de contrastes en la identificación de condiciones hepáticas, centrada en investigaciones publicadas entre 2020 y 2025. Utilizó bases de datos como PubMed, ScienceDirect y Scielo. Se incluyeron artículos originales y revisiones pertinentes, excluyendo estudios pediátricos y aquellos no revisados por pares. Resultados: El uso de gadolinio y contrastes hepatoespecíficos, especialmente el Gd-EOB-DTPA, ha demostrado ser una herramienta fundamental en la resonancia magnética para el diagnóstico y manejo de las lesiones hepáticas. Conclusión: Ambos tipos de agentes de contraste, gadolinio y contrastes hepatospecíficos, tienen ventajas y limitaciones en la evaluación de lesiones hepáticas. La elección del contraste adecuado debe considerar la naturaleza de las lesiones, el estado del hígado del paciente y los objetivos diagnósticos. Aunque el gadolinio es útil en la práctica clínica, los contrastes hepatospecíficos como Gd-EOB-DTPA y Gd-BOPTA ofrecen beneficios adicionales que mejoran el diagnóstico de lesiones hepáticas focales y optimizan el manejo de enfermedades hepáticas
Precisión Diagnóstica del Gadolinio vs. Contraste Hepatoespecífico en la Caracterización de Lesiones Hepáticas Focales en Resonancia Magnética: Revisión Sistemática
No full textMagnetic resonance imaging (MRI) is a highly resolving imaging technique that has become an essential tool for liver evaluation, especially in the diagnosis of focal liver lesions. The use of contrast agents, particularly gadolinium and liver-specific contrast agents, plays a crucial role in improving diagnostic accuracy. Methodology. A systematic review evaluating the diagnostic accuracy of contrast agents in identifying liver conditions focused on research published between 2020 and 2025. Databases such as PubMed, ScienceDirect, and Scielo were used. Original articles and relevant reviews were included, excluding pediatric and non-peer-reviewed studies. Results. The use of gadolinium and liver-specific contrast agents, especially Gd-EOB-DTPA, has proven to be a fundamental tool in MRI for the diagnosis and management of liver lesions. Conclusion. Both types of contrast agents, gadolinium and liver-specific contrast agents, have advantages and limitations in the evaluation of liver lesions. The choice of the appropriate contrast agent must consider the nature of the lesions, the patient's liver status, and the diagnostic objectives. Although gadolinium is useful in clinical practice, liver-specific contrast agents such as Gd-EOB-DTPA and Gd-BOPTA offer additional benefits that improve the diagnosis of focal liver lesions and optimize the management of liver disease.La resonancia magnética (RM) es una técnica de imagen altamente resolutiva que se ha convertido en una herramienta esencial para la evaluación del hígado, especialmente en el diagnóstico de lesiones hepáticas focales. La utilización de agentes de contraste, en particular el gadolinio y los contrastes hepatospecíficos, juega un papel crucial en la mejora de la precisión diagnóstica. Metodología. Revisión sistemática que evalúa la precisión diagnóstica de contrastes en la identificación de condiciones hepáticas, centrada en investigaciones publicadas entre 2020 y 2025. Utilizó bases de datos como PubMed, ScienceDirect y Scielo. Se incluyeron artículos originales y revisiones pertinentes, excluyendo estudios pediátricos y aquellos no revisados por pares. Resultados. El uso de gadolinio y contrastes hepatoespecíficos, especialmente el Gd-EOB-DTPA, ha demostrado ser una herramienta fundamental en la resonancia magnética para el diagnóstico y manejo de las lesiones hepáticas. Conclusión. Ambos tipos de agentes de contraste, gadolinio y contrastes hepatospecíficos, tienen ventajas y limitaciones en la evaluación de lesiones hepáticas. La elección del contraste adecuado debe considerar la naturaleza de las lesiones, el estado del hígado del paciente y los objetivos diagnósticos. Aunque el gadolinio es útil en la práctica clínica, los contrastes hepatospecíficos como Gd-EOB-DTPA y Gd-BOPTA ofrecen beneficios adicionales que mejoran el diagnóstico de lesiones hepáticas focales y optimizan el manejo de enfermedades hepáticas
Image analysis methods for dynamic hepatocyte-specific contrast enhanced MRI
No full textPatients with colorectal cancer are frequently presented with liver metastases for which (partial) resection is often the best therapy. However, the future remnant liver, the remaining part of the liver after resection, should allow adequate liver function to avoid liver failure. This thesis presents novel methods for the accurate voxel-wise estimation of the future remnant liver’s function based on pharmacokinetic modeling of dynamic contractenhanced (DCE)MRI. The methods comprise a variety of novel techniques for DCE-MRI of the liver: 1) 4D registration of the DCE series; 2) delineation of the liver, the liver vasculature and the liver’s anatomical segments; 3) pharmacokinetic (PK) modeling of the perfusion based on the intra-cellular contrast agent Gd-EOB-DTPA (Primovist); 4) assessment of the relation between DCE-MRI and hepatobiliary scintigraphy (HBS). Spatial alignment of the voxels in the 4D DCE-MRI is an important requirement for PK modeling. We exploit the proximity of deformation fields to sequentially register images in an ordered fashion. The global liver displacement helps in predicting the deformation ‘tendency’ along the time axis. The deformation tendency allows us to obtain a better starting point for the registration. Such a method aims to start the registration optimization close to the optimum and avoid getting trapped in a local minimum. We apply a liver-specific contrast agent, due to which the liver showsImPhys/Quantitative Imagin
Contrast enhancement effect of gadolinium-ethoxybenzyl-DTPA on magnetic resonance imaging of experimentally induced hepatic tumors in rats
No full text의학과/박사[한글]
Gadolinium -ethorsy benzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA)는 간세포에 흡수된 후 담도를 통해 배설되는 간담도 선택적 자기공명조영제로 개발된 약제로서, 간에 대한 자기공명영상(magnetic resonance imaging: MRI)검사에 사용할 경우 정상 간조직은 조영증강이 되는 반면 전이암과 같온 비간세포성 국소병변에는 조영효과를 나타내지 않아 병변의 검출감도를 높이는 것으로 알려져 있다. 그러나 원발성 간암종의 경우에는 정상 간조직 뿐 아니라 암종에 대해서도 조영증강을 일으킬 수 있을 것으로 예측되
어, 이에 대해서도 병변의 검출감도를 높여줄 수 있는 지는 의문이 될 수 있다. 따라서 본 연구는 원발성 간암종의 MRI에서 이 제제의 유용성을 평가하고자하였다.
3'-methyl-4-dimethylaminoazobenzene(3'-Me-DAB)을 투여하여 원발성 간암종을 유발한 12마리의 Sprague-Bawler 계의 흰쥐에 조영제 투여전 및 Gd-EOB-DTPA 25 μmo1/kg 투여후의 T1 강조영상을 1.5T MRI 장치하에서 얻었다. MRI 검사후 적출한 간에서 육안적으로 측정한 암종의 총 수는 125개였으며, 조영전 MRI에서 51개(41%)가 관찰된 반면, 조영후에는 80개(64%)가 발견되어서 암종의 검출감도는 통계적으로 유의하게 상승하였다(p＜0.01). 종괴의 크기를 직경 5mm를 기준으로 나누었을 때, 직경 5mm 미만 92개 중 조영전 23개(25%), 조영후에는 49개(53%)가 발견 되어 유의한 향상을 보였으나(p0.05). 조영후 영상에서 정상간의 신호강도는 761.0±155.6에서 1315.0±249.8로 76±33%의 증가를 보였으며, 암종의 신호강도는 563.9±143.9에서 731.3±221.5로 35±31% 증가하였다. 조영제 투여후 영상 배경의 잡음의 신호강도 또한 85.7±50.3에서 122.2±109.1로써 32±32%의 상승을 보였다. 정상 간의 신호강도대잡음비는 조영전 10.9±4.4에서 조영후 15.6±8.0으로 38±33% 상승하였으나(p＜0.05), 암종의 신호강도대 잡음비는 조영전 8.2±3.7에서 조영후 8.8±5.4로 4±32%만의 상승을 보였다(P>0.05). 정상 간의 조영도는 76±33%이었고, 암종의 조영도는 32±34%였다. 정상 간조직과 암종 사이의 대조도대잡음비는 조영전 5.55±2.88, 조영후 13.25±6.82로, 187±179% 상승하였다(p<0.01).
이상의 결과를 종합하면, 간암종에 대한 MRI 검사에서 Gd-EOB-DTPA의 사용은 정상 간조직 및 원발성 간암종 모두가 조영증강을 일으킬 수 있으나 정상 간조직에서의 조영정도가 더욱 현저하여, Gd-EOB-DTPA 사용이 간암종의 검출감도를 높이는 것을 알 수 있으며, 앞
으로 인체에 대한 안정성 검사가 완료되면, 전이성 암종의 발견을 위한 목적 뿐 아니라 원발성 간암종의 검출감도를 높이기 위한 목적으로도 사용할 수 있을 것으로 생각한다.
[영문]
Gadolinium-ethoxybenzyl-diethylenetriamine-pentaacetic acid (Gd-EOB-DTPA ) is newly developed hepatocyte-directed contrast media for magnetic resonance imaging(MRl). It has been groved to be effective to evaluate metastatic neoplasms in rats because it enhance normal liver but the metastatic lesions. However, it is
suspective whether it may obscure the primary tumor by enhancing the primary tumor tissue not only the normal liver because it can be uptaken by hepatocyte. In the present study, therefore, the author investigated the effectiveness of Gd-EOB-DTPA in the MRI of experimentally induced primary hepatic neoplasms in rats. Primary hepatic tumors had been induced on 12 male Sprague-Dawley rats by administration of the experimental diet containing 3'-methyl-dimethylaminoazobenzene for 12 weeks.
Precontrast and postcontrast T1weighted images after injection of 25 μmol/kg of Gd-EOB-DTPA were obtained on 1.57 system.
In all rats, overall 125 tumors were identified on resected liver, 51(41%) lesions on precontrast images and 80(64%) lesions on postcontrast images, respectively (P0.05). For 92 tumors smaller than
5 mm in diameter, 23(25%) and 49(53%) of the tumors were detected on pre-and postcontrast images respectively (p<0.01). Liver signal was increased by 76±33% from 761.01±155.6 to 1315.0±249.8, and tumor signal was increased by 35±31% from
563.9±143.9 to 731.3±221.5. Background noise was also increased by 32±32% from 85.7±57.3 to 122.7±109.1. Signal to noise ratio(SNR) of tumor was increased by 38±33% from 10.9±4.4 to 15.6±8.0(P<0.05). SNR of tumor was increased by 4±32% from 8.2±3.7 to 8.8±5.4 (p＜0.05). Contrast enhancement of the normal liver was 76±33% and that of tumor was 32±34% in average. Liver to tumor contrast to noise ratio(CNR) was increased by 187 ± 179%, from 5.55±2.88 to 13.25±6.82 (P<0.01).
From the results it is disclosed that Gd-EOB-DTPA may enhance both normal hepatic tissue and primary hepatic tumor, but it is more conspicuous on normal hepatic tissue, therefore, the liver to tumor CNR and the detection rate is increased on postcontrast images. It is expected that, if this agent is approved to being used clinically, Gd-EOB-DTPA will be helpful to evaluate the primary hepatic neoplasm.restrictio
Pengaruh Build Up Angle Untuk Kestabilan Formasi Pada Proses Cabut Rangkaian BHA
No full textDirectional drilling is a method for directing a drilled well along a predetermined path to reach the target. Vertical wells are usually defined as wells with a slope below 5°. Wells with a slope of more than 60° are also called directional wells.Directional drilling is only carried out for certain reasons and circumstances. The reasons for carrying out directional drilling are geographical reasons, geological reasons, and other reasons related to productivity issues.In this thesis the author tries to determine the KOP, azimuth, inclination and EOB points so that the process of extracting the BHA series can run smoothly without having to experience formation collapse or the BHA series being pinched in the formation in the MAR-1 well, followed by comparing the actual data
Holographic imaging of magnetization in a single layer nano-contact spin transfer oscillator
No full textThis is the author accepted manuscript. The final version is available from IEEE via the DOI in this record.Time-averaged images of the magnetization within single layer spin transfer oscillators have been obtained using the holography with extended reference by autocorrelation linear differential operator (HERALDO) technique. Transport measurements on a Pd(5)- Cu(20)- Ni 81 Fe 19 (7)-Cu(2)-Pd(2) (in nm) stack with a 100 nm diameter nano-contact reveal the presence of vortex dynamics. Magnetic images of the device for injected current values of 24mA and -24mA suggest that a vortex has been ejected from the nano-contact and become pinned at the edge of the region that is visible through the Au mask.The author was supported by CONICYT–Becas Chile. P. Keatley was supported by EPRSC grant EP/I038470/1
Localisation and substrate specificities of transglycanases in charophyte algae relate to development and morphology
No full textCell wall-modifying enzymes have been previously investigated in charophyte green algae (CGA) in cultures of uniform age, giving limited insight into their roles. Therefore, we investigated the in situ localisation and specificity of enzymes acting on hemicelluloses in CGA genera of different morphologies and developmental stages. In vivo transglycosylation between xyloglucan and an endogenous donor in filamentous Klebsormidium and Zygnema was observed in longitudinal cell walls of young (1 month) but not old cells (1 year), suggesting that it has a role in cell growth. By contrast, in parenchymatous Chara, transglycanase action occurred in all cell planes. In Klebsormidium and Zygnema, the location of enzyme action mainly occurred in regions where xyloglucans and mannans, and to a lesser extent mixed-linkage beta-glucan (MLG), were present, indicating predominantly xyloglucan: xyloglucan endotransglucosylase (XET) activity. Novel transglycosylation activities between xyloglucan and xylan, and xyloglucan and galactomannan were identified in vitro in both genera. Our results show that several cell wall-modifying enzymes are present in CGA, and that differences in morphology and cell age are related to enzyme localisation and specificity. This indicates an evolutionary significance of cell wall modifications, as similar changes are known in their immediate descendants, the land plants. This article has an associated First Person interview with the first author of the paper
Effects of intraoperative inspired oxygen fraction (FiO2 0.3 vs 0.8) on patients undergoing off-pump coronary artery bypass grafting: the CARROT multicenter, cluster-randomized trial
No full textBACKGROUND: To maintain adequate oxygenation is of utmost importance in intraoperative care. However, clinical evidence supporting specific oxygen levels in distinct surgical settings is lacking. This study aimed to compare the effects of 30% and 80% oxygen in off-pump coronary artery bypass grafting (OPCAB). METHODS: This multicenter trial was conducted in three tertiary hospitals from August 2019 to August 2021. Patients undergoing OPCAB were cluster-randomized to receive either 30% or 80% oxygen intraoperatively, based on the month when the surgery was performed. The primary endpoint was the length of hospital stay. Intraoperative hemodynamic data were also compared. RESULTS: A total of 414 patients were cluster-randomized. Length of hospital stay was not different in the 30% oxygen group compared to the 80% oxygen group (median, 7.0 days vs 7.0 days; the sub-distribution hazard ratio, 0.98; 95% confidence interval [CI] 0.83-1.16; P = 0.808). The incidence of postoperative acute kidney injury was significantly higher in the 30% oxygen group than in the 80% oxygen group (30.7% vs 19.4%; odds ratio, 1.94; 95% CI 1.18-3.17; P = 0.036). Intraoperative time-weighted average mixed venous oxygen saturation was significantly higher in the 80% oxygen group (74% vs 64%; P < 0.001). The 80% oxygen group also had a significantly greater intraoperative time-weighted average cerebral regional oxygen saturation than the 30% oxygen group (56% vs 52%; P = 0.002). CONCLUSIONS: In patients undergoing OPCAB, intraoperative administration of 80% oxygen did not decrease the length of hospital stay, compared to 30% oxygen, but may reduce postoperative acute kidney injury. Moreover, compared to 30% oxygen, intraoperative use of 80% oxygen improved oxygen delivery in patients undergoing OPCAB. Trial registration ClinicalTrials.gov (NCT03945565; April 8, 2019). © 2023. The Author(s).ope
