1,720,973 research outputs found
TISSUE CLASSIFICATION AS NON- INVASIVE ASSESSMENT METHODS FOR LIVER STEATOSIS
No full textHepatic steatosis (HS) is one of the most important organ donor characteristics that can
influence negatively graft function and so liver transplantation (LT) outcome. Despite
histopathological analysis of liver tissue is currently the gold reference standard for
diagnosis and grading of HS in liver grafts, it is invasive, time-consuming and expensive.
Due to the short time availability between liver procurement and transplantation, the
surgeon usually performs HS assessment through clinical evaluation (medical history,
blood tests) and qualitative visual liver graft assessment.
In this context, visual liver texture analysis is recognized as crucial in grading HS: livers
that cannot be transplanted due to high HS are usually characterized by inhomogeneous
texture and are more yellowish than the transplantable ones. It is nonetheless recognized
that the precise estimation of HS remains challenging even in experienced surgeon’s hands.
The automatic image-based intraoperative tissue classification is a valuable solution to
provide decision support to the liver surgeon and context awareness intra-operatively.
The surgical data science (SDS) community is focusing more and more on machine
learning (ML) to perform tissue classification in the operating room (OR). However,
several technical challenges as noise in the image, varying illumination level, different
camera pose with respect to the tissues, and intra- and inter-patient tissue variability,
are still present, hampering the clinical translation of the developed methodology in the
clinical practice.
On this background, the overall goal of this PhD thesis was to tacke most of theese
issues by developping an hardware device able to allow high-quality standard intraoperative
image acquisition and a framework for ML-based SDS algorithms for robust and
reliable tissue classification for intraoperative images.
In particular, the contributions of this PhD work are:
1. A new tool for intraoperative RGB images acquisition
2. A new method for reliable hepatic tissue classification that utilised images acquired
with the new device and non-invasive biomarkers donor’s data
3. A machine-learning based evaluation of non-invasive biomarkers donor’s data with
the goal of estimate the real value of clinical and biochemical donor’s features in
HS classification
4. A new method for hepatic tissue classification arising from human visual cortex
method, that utilised only images acquired with the new device designed
This PhD thesis work lies in the wider research field of SDS, which aims at providing
the surgeons with decision support and context awareness during interventional medicine
procedures. The methodologies presented in this PhD thesis demonstrated the feasibility
of using SDS ML-based algorithms for intra-operative hepatic tissue classification in liver
transplantation setting. The methodological progress made in this work highlights the
potential of SDS ML-based algorithms in extracting useful information implicitly contained
in intra-operative optical images, overcoming challenges typical of intra-operative
tissue classification to support surgeons during liver transplanatation procedures
Total laparoscopic right colectomy: The duodenal window first approach
Full text linkBackground Total laparoscopic right colectomy (TLRC) is a demanding procedure requiring laparoscopic skills and expertise in surgical oncology. Identifying the correct plane of dissection may be difficult. A correct management of ileocecal and right colic vascular pedicles is pivotal to achieve an oncological resection and the adequate blood supply of ileal and colic stumps. Methods We describe a technique for TLRC with a duodenum-first approach. Using three ports, dividing the "duodenal window", ileocecal and right colic vascular pedicles, and the right ureter are easily identified. The procedure is completed with an intracorporal stapled side-by-side anastomosis. Results In 2014, 19 patients underwent TLRC using this technique. The median operative time was 178 min (132-237 min) and median intraoperative blood loss reached 60 mL (10-400). Conversion rate was 15.8%. No urinary tract, vascular, duodenal injury or anastomotic fistula were reported. Fifteen patients (79%) underwent a colectomy for cancer with a median of 16 (7-27) harvested lymph-nodes and 100% of R0-resection. Minor morbidity (Clavien-Dindo I-II) was 52.6% mainly related to cardiopulmonary complications (26.3%). Severe morbidity (Clavien-Dindo ≥ III) was 10.5% (two patients), including one reoperation (due to a sepsis related to an intra-abdominal abscess) and one death (due to complications of an aortic aneurism). Median hospital stay was 7 days (2-23 days). Long-term outcomes are unremarkable. Conclusions Using three trocars, the "duodenal window" approach to TLRC is technically feasible and safe, with good outcomes. The early access to the duodenum and the exposure of ilea-cecal and right colic pedicles rationalizes the procedure
Letter to the Editor: Objective evaluation of liver steatosis in donor organs—Potential usefulness of noninvasive assessment
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Reappraisal of primary hepatic lymphoma: Is surgical resection underestimated?
No full textPrimary hepatic lymphoma (PHL) is defined as a lympho-proliferative disorder limited to the liver without any involvement of the spleen, lymph nodes, bone marrow or blood. Diffuse large B-cell lymphoma (DLBCL) is the most common histological type counting more than 60-80% of all PHL. Usually, it occurs in middle-aged men with aspecific symptoms and diagnosis is confirmed by histopathology. In order to expand current knowledge and to investigate an optimal therapeutic strategy, a systematic review of literature was conducted in February 2016. A total of 274 articles were retrieved, and after exclusion, 55 were retained, reporting 147 cases of PHL. Patients were mainly men (64.9%) with a median age at diagnosis of 57 years (range: 17-92) and right hepatic lobe involvement (69.6%). Among the 147 patients, 9% received no therapy while 77% underwent treatment including chemotherapy, surgery and radiotherapy in 64%, 26% and 1% of cases, respectively. Mean follow-up was 22.6 months (range: 0.2-360). Overall mortality was 29.2% with a 90-day mortality of 26%. Risk factors for increased mortality include; bilobar lesions (p = 0.001), right lobe localisation (p = 0.003) and non-surgical approach or the absence of any treatment (p = 0.001). A trend towards favourable outcomes for young patients (mean = 50.4 years) with a large liver lesion was achieved by surgical management of PHL but this did not achieve statistical significance. Statistical analysis indicates that in cases of resectable disease, an aggressive surgical approach in selected patients leads to increase long-term survival. Thus, two hypotheses should be assessed in further randomized studies: 1°) resectable PHL is a less severe form or 2°) hepatectomy is an effective treatment for PHL
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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