Rodrigo Tejos

Intrahepatic portal vein blood volume estimated by non-contrast magnetic resonance imaging for the assessment of portal hypertension.

PURPOSE To investigate the feasibility of estimating the portal vein blood volume that flows into the intrahepatic volume (IHPVBV) in each cardiac cycle using non-contrast MR venography technique as a surrogate marker of portal hypertension (PH). MATERIALS AND METHODS Ten patients with chronic liver disease and clinical symptoms of PH (40% males, median age: 54.0, range: 44-73 years old) and ten healthy volunteers (80% males, median age: 54.0, range: 44-66 years old) were included in this study. A non-contrast Triple-Inversion-Recovery Arterial-Spin-Labeling (TIR-ASL) technique was used to quantify the IHPVBV in one and two cardiac cycles. Liver (LV) and spleen volumes (SV) were measured by manual segmentation from anatomical MR images as morphological markers of PH. All images were acquired in a 1.5T Philips Achieva MR scanner. RESULTS PH patients had larger SV (P=0.02) and lower liver-to-spleen ratio (P=0.02) compared with healthy volunteers. The median IHPVBV in healthy volunteers was 13.5cm(3) and 26.5cm(3) for one and two cardiac cycles respectively, whereas in PH patients a median volume of 3.1cm(3) and 9.0cm(3) was observed. When correcting by LV, the IHPVBV was significantly higher in healthy volunteers than PH patients for one and two cardiac cycles. The combination of morphological information (liver-to-spleen ratio) and functional information (IHPVBV/LV) can accurately identify the PH patients with a sensitivity of 90% and specificity of 100%. CONCLUSION Results show that the portal vein blood volume that flows into the intrahepatic volume in one and two cardiac cycles is significantly lower in PH patients than in healthy volunteers and can be quantified with non-contrast MRI techniques.

Allowing New Opportunities in Advanced Laparoscopy Training Using a Full High-Definition Training Box

Introduction. Simulated laparoscopy training is limited by its low-quality image. A high-definition (HD) laparoscopic training box was developed under the present necessity of simulating advanced surgery. Objective. To describe and test a new HD laparoscopic training box for advanced simulation training. Methods. We describe the features and image quality of the new training box. The simulator was tested and then evaluated by a group of 76 expert surgeons using a 4-item questionnaire. To assess the effectiveness of training using this simulation box, 15 general surgery residents were trained to perform a laparoscopic jejuno-jejunostomy in a validated simulation program. They were assessed with objective rating scales before and after the training program, and their results were compared with that of experts. Results. The training box was assembled using high-density fiberglass shaped as an insufflated abdomen. It has an adapted full-HD camera with a LED-based illumination system. A manually self-regulated monopod attached to the camera enables training without assistance. Of the expert surgeons who answered the questionnaire, 91% said that the simulation box had a high-quality image and that it was very similar to real laparoscopy. All residents trained improved their rating scores significantly when comparing their initial versus final assessment (P < .001). Their performance after completing the training in the box was similar to that of experts (P > .2). Conclusions. This novel laparoscopic training box presents a high-resolution image and allows training different types of advanced laparoscopic procedures. The simulator box was positively assessed by experts and demonstrated to be effective for laparoscopy training in resident surgeons.

Uniportal video-assisted thoracic surgery lobectomy using a novel perfused ex vivo simulation model

Simulation may provide a solution to acquire advanced skills in thoracic surgery, however to date there are no reports in the English literature about a perfused ex vivo model. We developed a low cost and hi fidelity model using an ex vivo in bloc heart and lung specimen from a swine. The swine was previously used in a non-thoracic experiment, so we extracted the lung and heart for this ex vivo based model to reduce animal use. The cost of the whole model is 70 USD and it can be reused many times changing the ex vivo tissue, so this model may help reduce the costs and animal use associated to this high complexity surgery.

Niveles séricos de alanino-aminotransferasa en población chilena: análisis de los resultados de la encuesta nacional de salud 2009-2010

BACKGROUND Determination of Alanine aminotransferase serum levels ([ALT]s) is a sensitive ana reliable test for liver diseases. AIM To report the prevalence of abnormal [ALT]s in Chilean population and to identify associated variables. METHODS We analyzed data from a random sub-sample of 2,794 adults surveyed during the second Chilean National Health Survey. Abnormal [ALT]s were defined by using three different cut-off values (COV), two fixed COV (COV1: > 30 IU/L in men and > 19 IU/L in women and COV2 pre-defined by the performing laboratory) and a COV adjusted by age, weight and sex (COV3 > 31 IU/L for women and > 44 IU/L and men > 42 IU/L and > 66 IU/L with a BMI > 23). Logistic regression analysis was performed to determine risk factors for elevated [ALT]s. RESULTS Mean [ALT]s values were 30.14 I U/L in men and 22.03 IU/L in women. The observed prevalence of abnormal [ALT]s defined by different COV were 38%, 11.5%, and 8.1% for COV1, COV2 and COV3 respectively. Variables independently associated to abnormal [ALT]s in a multivariate analysis were the following: serum gamma-glutamyl-transpeptidase (OR: 1.055 [95% CI 1.033-1.078]) and body mass index (OR:1.13 [95% CI 1.09-1.17]). Variables inversely associated with abnormal [ALT]s (COV1) were mole gender (OR-.0.976 [95% CI 0.96-0.99) and HDL-cholesterol (OR:0979 [95% CI 0.96-0.99]). CONCLUSIONS Independently of the COV used, Chilean population exhibits a high prevalence of abnormal [ALT]s which may reflect a significant burden of liver disease. Non-alcoholic fatty liver disease could be a major contributor to elevated [ALT]s considering the association of abnormal [ALT]s and metabolic variables.