Emilio Gómez-González

Optical analysis of computed tomography images of the liver predicts fibrosis stage and distribution in chronic hepatitis C

This study was undertaken to evaluate an image processing method for assessing liver fibrosis in conventional computed tomography (CT) scans in patients with chronic hepatitis C. Two cohorts (designated “estimation,” n = 34; and “validation,” n = 107) of chronic hepatitis C patients were assessed using digitized conventional helical CT. Weighted CT mean fibrosis (Fibro‐CT) was calculated as a nonlinear weighted mean F‐score for each sample. Fibrosis was defined according to Scheuer on the F0 to F4 scale by 2 pathologists blinded regarding the Fibro‐CT data. Fibrosis according to Fibro‐CT correlated with histology‐determined fibrosis (r = 0.69; P < 0.001) and with increasing F‐stage: F0 = 0.23 ± 0.39; F1 = 0.90 ± 0.99; F2 = 1.41 ± 0.94; F3 = 2.79 ± 0.55; F4 = 3.15 ± 0.35 [analysis of variance: P < 0.0001). The receiver operating characteristics curve to diagnose significant fibrosis (≥F2) was 0.83; 95% confidence interval (95%CI), 0.75 to 0.91; and, to diagnose advanced fibrosis (≥F3), was 0.86, 95%CI: 0.80 to 0.93. The correlation between Fibro‐CT and fibrosis was higher in patients with homogeneous distribution of fibrosis than in patients with heterogeneous distribution (r = 0.77 versus r = 0.43; P < 0.05). Conclusion: Optical digital analysis of CT images of the liver is effective in determining the stage and distribution of liver fibrosis in chronic hepatitis C. In patients with homogeneous fibrosis distribution, the correlation between Fibro‐CT and histology was better than in patients with heterogeneous distribution. Fibro‐CT is a simple to use, readily available, and useful method for the diagnosis of fibrosis in patients with chronic hepatitis C. (HEPATOLOGY 2008.)

THE ROLE OF THE ELECTRICAL CONDUCTIVITY AND VISCOSITY ON THE MOTIONS INSIDE TAYLOR CONES

Abstract The role of the electrical conductivity and viscosity on the liquid motions inside Taylor cones has been investigated. The electrical conductivity plays an essential role since it determines the electric tangential stresses acting on the cone surface. Flow visualization shows that two different patterns of the liquid motion can be distinguished. One, for liquids with sufficiently high values of the electrical conductivity and viscosity which corresponds to small values of the Reynolds number and the other for less viscous and less conducting liquids for which the characteristic Reynolds number of the flow is larger than unity. Some theoretical models of the liquid motions are given and compared to the flow patterns observed in the laboratory.

Imaging biomarkers for steatohepatitis and fibrosis detection in non-alcoholic fatty liver disease.

There is a need, in NAFLD management, to develop non-invasive methods to detect steatohepatitis (NASH) and to predict advanced fibrosis stages. We evaluated a tool based on optical analysis of liver magnetic resonance images (MRI) as biomarkers for NASH and fibrosis detection by investigating patients with biopsy-proven NAFLD who underwent magnetic resonance (MR) protocols using 1.5T General Electric (GE) or Philips devices. Two imaging biomarkers (NASHMRI and FibroMRI) were developed, standardised and validated using area under the receiver operating characteristic curve (AUROC) analysis. The results indicated NASHMRI diagnostic accuracy for steatohepatitis detection was 0.83 (95% CI: 0.73–0.93) and FibroMRI diagnostic accuracy for significant fibrosis determination was 0.85 (95% CI: 0.77–0.94). These findings were independent of the MR system used. We conclude that optical analysis of MRI has high potential to define non-invasive imaging biomarkers for the detection of steatohepatitis (NASHMRI) and the prediction of significant fibrosis (FibroMRI) in NAFLD patients.

Initial experience involving treatment and retreatment with carmustine wafers in combination with oral temozolomide: long-term survival in a child with relapsed glioblastoma multiforme.

Background Glioblastomas occur infrequently in children, and the prognosis is better than for glioblastomas seen in adults. Aggressive treatment is justified in pediatric patients. Observations We present the case of a 6-year-old child with malignant posterior temporal glioma treated with surgery, radiotherapy, local chemotherapy with carmustine wafers, and oral therapy with temozolomide, both at initial diagnosis and at relapse 18 months later. After 6 years, the patient seems healthy with no focal neurologic signs, and imaging studies show no evidence of disease. Conclusion Multimodal therapy was found to have a very positive outcome for a child with malignant glioma.

Obtention of meridian caustics and catacaustics by means of stigmatic approximating surfaces

We present an analysis of the problem of determination of meridian caustics and catacaustics by using the method of minimization of functionals. The well known result that a conic is an stigmatic profile for its foci is then reobtained for both refracting and refracting profiles. The original proposed method is to approximate each point P of the reflecting (or refracting) profile by an appropriated conic, whose focus is precisely the caustic point corresponding to P. The equations obtained for caustics and catacaustics go beyond some difficulties inherent to the classical method of envelopes and allow us to obtain caustics and catacaustics of non-analytical surfaces, even with irregularities and perceptible or imperceptible cracks.

Can fetus feel pain in the second trimester? Lessons learned from a sentinel event

Dear Editor: Current references fail to prove fetal perception of pain before the third trimester and little or no evidence addresses the effectiveness of direct fetal anesthetic or analgesic techniques [1]. However, mortality related to fetal procedures remains over 10–20% [2]. Open fetal surgery (OFS) remains a major procedure for mother and fetus. In such cases, fetus anesthesia/analgesia can be provided by different routes but, in our opinion, direct administration is mandatory [3]. A 24-week fetus undergoing OFS for MMR under a specific protocol [4] for anesthesia and management was designed by our group: rapid sequence induction and placental support with sevoflurane, remifentanil, and phenylephrine. Intramuscular (IM) vecuronium (0.2 μg/kg), atropine (0.01 mg/kg), and fentanyl (10–20 μg/kg) are directly administered to the fetus (Fig. 1). After 4 min of exposure, it developed fetal bradycardia, evident in continuous ultrasonographic heart monitoring. Immediate evaluation confirmed trans-placental flow maintenance and discarded cord compressions, massive loss of amniotic fluid or maternal systemic alterations, but we identified a protocol transgression: fetus anesthesia was not being delivered. Immediately, IM epinephrine was administered together with pre-planned anesthesia and surgical procedure was temporarily stopped. After recovery, completion of the untethering and spinal reconstruction was possible and the postoperative period was uneventful. We retrospectively analyzed our series (11 cases of MMR by OFS). Only the fetus described in this case did not receive parenteral anesthesia and showed signs of stress response to pain. We had no intrauterine or immediate fetal loss for extreme prematurity. The issue whether fetuses are capable of feeling pain, or not, is still controversial [1]. Pain is composed of two parts: a physiologic reaction towards a noxious stimulus, nociception or stress response, and an emotional negative perception. Autonomic effects can be suppressed by the administration of analgesics. The fetal stress response to noxious stimulation that we observed in this case does not prove that the fetus has a conscious perception of pain. However, it is very unlikely that there may be pain perception without a stress response, as it is often used as a surrogate indicator for pain [1]. The immature pain system is capable of mounting behavioral responses to painful stimuli, as seen by the movements of the fetus away from the stimulus during minimal invasive fetal procedures (MIFP). Even if the sensory cortex itself is not fully developed, other structures in the developing brain can act as surrogates for it. Neurons of the subplate zone are particularly susceptible to preterm injuries, and this zone is active in the second-trimester human fetus. As a consequence, fetus may still be able to process the information from nociceptive stimuli and model the developing nervous system in response to pain [1]. One of the key aspects of anesthesia in open fetal procedures is to promote uterine relaxation, maintaining both maternal and fetal circulation stable and, once surgery is completed, to offer perfect analgesic to avoid the contractions due to pain, thus finally reducing the preterm delivery [4]. In this scenario, noxius stimulus may probably be high enough to * María J. Mayorga-Buiza mayorgabuiza@gmail.com

Cardiac pulmonary resuscitation in prone position. The best option for posterior fossa neurosurgical patients

325-377. 3. O’Donnell B, Iohom G. An estimation of the minimum effective anesthetic volume of 2% lidocaine in ultrasound-guided axillary brachial plexus block. Anesthesiology. 2009;111:25-29. 4. Harper GK, Stafford MA, Hill DA. Minimum volume of local anaesthetic required to surround each of the constituent nerves of the axillary brachial plexus using ultrasound guidance: a pilot study. Br J Anaesth. 2010;104:633-636.

Long-term reliability of the telemetric Neurovent-P-tel sensor: in vivo case report

Intracranial pressure (ICP) measurements are imperative for the proper diagnosis and treatment of several neurological disorders. Telemetric sensors have shown their utility for ICP estimation in short-term monitoring in humans. However, their long-term reliability is uncertain. The authors present the case of a 37-year-old woman diagnosed with benign intracranial hypertension and obesity. The patient underwent gastric bypass surgery for ICP control. In order to monitor ICP before and after bariatric surgery, a Neurovent-P-tel sensor was implanted in the left frontal lobe. After gastric bypass, normal ICP values were recorded, and the patients visual fields improved. However, the patient experienced incapacitating daily headaches. The authors decided to implant a Codman Microsensor ICP transducer in the right frontal lobe to assess the long-term reliability of the Neurovent-P-tel measurements. A comparison of the recordings at 24 and 48 hours showed good correlation and reliability during long-term monitoring with the Neurovent-P-tel, with minimal zero drift after 11 months of implantation.

Virtual holographic recognition and its applications in medicine and other fields

Novel digital applications developed from analog holographic recognition techniques are presented. Virtual Holographic Recognition (VHR) substitutes physical processes in matched filtering by digital equations and calculates light distribution on the observation plane. If a certain image is defined as a reference, bright light spots corresponding to coincidences between the searched element and the image under study can be numerically calculated with a high degree of accuracy. Since peak values and radial symmetry of values define the degree of coincidence with the reference, this method can be used to find elements similar-up to any degree- to a given reference in a complex image. Current applications include detection and location of malignant masses and nodules in mammograms, computed-tomography (CT) chest scans and conventional digitized radiographs. If the image taken by a digital video camera is continuously processed and the position of the peak corresponding to a reference is tracked on a screen, it allows for guiding of persons in complex environments. Application to guiding of disabled in sport courts is also described.