1,721,006 research outputs found
Biomarcatori imaging di composizione corporea tra cui fegato grasso, sarcopenia e distribuzione del grasso corporeo: ruolo diagnostico e prognostico in diverse patologie metaboliche, infettive ed oncologiche.
No full textRazionale: i test di imaging possono essere utilizzati per ottenere biomarcatori di composizione corporea.
Imaging nella valutazione della steatosi epatica non alcolica (NAFLD)
Per capire il ruolo dei biomarcatori di imaging nella valutazione della NAFLD, è stata condotta una revisione sistematica per valutare le linee guida, concentrandosi sugli approcci di screening nei pazienti ad alto rischio. Delle 14 linee guida incluse, quelle britanniche e quelle del Nord America avevano i punteggi più alti.
Applicando un algoritmo di valutazione basato su queste linee guida, 272 pazienti consecutivi con diabete di tipo 2 sono stati prospetticamente stratificati sulla base dei test di funzionalità epatica (LFT) e di scores di steatosi/fibrosi, generando 106 (39%) invii all’epatologo e 32 (11,8%) invii a biopsia epatica. Le 14 biopsie eseguite sono risultate in 12 NASH e 1 fibrosi significativa.
Un algoritmo simile è stato applicato a 3 coorti prospettiche di pazienti HIV (totale 1534 pazienti), 313 (20,4%) con diabete o obesità, richiedendo quindi lo screening NAFLD. Tra questi 313 pazienti, 123 (39,3%) sono stati indirizzati all'epatologo. L’estensione dell'algoritmo anche a pazienti con altre comorbidità metaboliche (totale 1062 pazienti), richiederebbe l’invio all’epatologo in 341 (32,1%) pazienti.
Una seconda revisione sistematica con l'obiettivo di valutare l'accuratezza dell'imaging rispetto alla biopsia nella diagnosi di NASH ha compreso 58 studi e diverse tecniche di imaging, con l'ecografia e la RM (elastografia e tecniche non elastografiche) che davano i risultati più promettenti (AUROC 0.80- 1), ma derivanti da singoli studi senza validazione indipendente.
In uno studio prospettico 18 pazienti NAFLD inviati a biopsia (4 fibrosi significative e 15 NASH) sono stati sottoposti a ecografia con US-Fatty Liver Index e Shear Wave Elastography e RM epatica multiparametrica senza mezzo di contrasto. L’US ha dimostrato una scarsa performance nella diagnosi di NASH (sensibilità 50%, specificità 25%), ma ha permesso di escludere fibrosi significativa. Il T1-mapping in RM ha dimostrato sensibilità-specificità del 67%-79% per fibrosi e del 38%-80% per NASH.
Steatosi epatica in pazienti oncologici
In uno studio retrospettivo di 283 pazienti con cancro del retto in stadio II-IV, 90 (31,8%) avevano steatosi epatica alla TC baseline. La prevalenza di metastasi epatiche sincrone (LM) era maggiore nei pazienti con steatosi, ma l'incidenza di LM metacrone era simile. In una piccola analisi di 63 pazienti senza steatosi al basale e trattati con chemioterapia neoadiuvante, il danno epatico indotto dalla chemioterapia (definito sulla base di TC e LFT) era associato a maggiore incidenza di LM e peggiore sopravvivenza.
Sarcopenia e grasso ectopico
-COVID-19
In uno studio di 318 pazienti COVID-19 che hanno eseguito la TC torace al pronto soccorso, la densità del muscolo pettorale, le aree di tessuto adiposo totale, viscerale e intermuscolare (TAT, IVA e IMAT) all’altezza di T7-T8 sono state misurate retrospettivamente. Nei modelli multivariati, la diminuzione della densità muscolare, l'aumento di TAT, IVA e IMAT erano fattori di rischio per ricovero e ventilazione meccanica o morte. Parte dell'effetto dell'età sulla morte era mediato dalla sarcopenia.
Linfoma diffuso a grandi cellule B (DLBCL)
In uno studio retrospettivo su 116 pazienti con DLBCL, lo skeletal muscle index (SMI) e la densità (SMD) e l'IMAT a livello di L3 e della coscia prossimale (PT) sono stati ottenuti dalla TC baseline. Una bassa qualità (L3-SMD), ma non una bassa quantità muscolare (L3-SMI), era associata alla cessazione precoce della terapia, e a più brevi OS/PFS. Nei modelli multivariati, L3-SMD è rimasta associata a OS e l'aumento di PT-IMAT era un fattore prognostico sfavorevole per OS/PFS.Rationale: Imaging tests may be used to obtain different biomarkers describing body composition.
Imaging in Non-Alcoholic Fatty Liver Disease (NAFLD) assessment
To understand which role imaging biomarkers may have in NAFLD assessment, firstly a systematic review was conducted to appraise NAFLD guidelines, focusing on screening approaches in high-risk patients. Of the 14 guidelines included, British and North America guidelines had the highest scores.
By applying a NAFLD assessment algorithm based on these guidelines, 272 consecutive type-2 diabetes patients at their first diagnosis were prospectively enrolled and stratified based on liver function tests (LFT) and steatosis/fibrosis scores, generating 106 (39%) hepatologist referrals and 32 (11.8%) liver biopsy referrals. The 14 biopsies performed resulted in 12 steatohepatitis and 1 significant fibrosis.
A similar algorithm was applied to 3 prospective cohorts of HIV patients (total 1534 patients), 313 (20.4%) with diabetes or obesity, thus requiring NAFLD screening. Among these 313 patients, 123 (39.3%) were referred to the hepatologist. When extending the algorithm also to patients with other metabolic comorbidities (total 1062 patients), 341 (32.1%) would require hepatologist referral.
A second systematic review with the aim of evaluating accuracy of imaging vs biopsy in diagnosing steatohepatitis (NASH) among NAFLD patients included 58 studies and several imaging techniques, with US and MR elastography and non-elastographic techniques having the most promising results (AUROC 0.80-1), but results derived mostly from single studies without independent validation.
In an ongoing prospective study, 18 high-risk NAFLD patients referred for liver biopsy (4 significant fibrosis and 15 NASH) were enrolled and underwent US including US-Fatty Liver Index (US-FLI) and Shear Wave Elastography (SWE), and multiparametric liver non-contrast-enhanced MR. US resulted in poor accuracy for NASH diagnosis (sensitivity 50%, specificity 25%), but ruled out significant fibrosis. MR-T1 mapping resulted in 67% sensitivity and 79% specificity for significant fibrosis, and 38% sensitivity and 80% specificity for NASH.
Fatty Liver in oncologic patients
In a retrospective study including 283 stage II-IV rectal cancer patients, 90 (31,8%) patients had baseline CT-defined liver steatosis. The prevalence of synchronous liver metastasis (LM) was higher in patients with steatosis (19% vs 13%), but the incidence of metachronous LM was similar, without any significant association. In a small analysis of 63 patients without baseline steatosis and treated with neoadjuvant chemotherapy, chemotherapy-induced liver damage (defined based on CT and LFT) was associated with higher incidence of LM and worst survival.
Sarcopenia and ectopic fat
-COVID-19
In a study including 318 consecutive COVID-19 patients who performed chest CT scan at emergency room, pectoralis muscle density, total, visceral, and intermuscular adipose tissue areas (TAT, VAT, and IMAT) at T7-T8 vertebrae were retrospectively measured. In multivariate models, decreased muscle density, increased TAT, VAT, and IMAT were risk factors for hospitalization and mechanical ventilation or death. Part of the effect of age on death was mediated by sarcopenia.
Diffuse large B-cell lymphoma (DLBCL)
In a retrospective study of 116 consecutive DLBCL patients, skeletal muscle index (SMI) and density (SMD) and IMAT at L3 vertebra and proximal thigh (PT) were obtained from baseline CT scan. Low muscle quality (L3-SMD), but not low muscle quantity (L3-SMI), was associated with early therapy termination, shorter overall and progression-free survivals (OS, PFS). In multivariable models, L3-SMD remained associated with OS, and increasing PT-IMAT was a poor prognostic factor for OS/PFS
HIV patients exhibit similar rates of emphysema progression observed in older HIV-uninfected patients with higher cumulative smoke exposure.
No full textHIV patients face the burden of chronic obstructive pulmonary disease (COPD). How quickly COPD phenotypes such as emphysema progress, what risk factors are associated with COPD progression in an HIV-infected population, and whether this risk of progression is in excess compared to HIV-uninfected patients are unknown
MR quantitative biomarkers of non-alcoholic fatty liver disease: technical evolutions and future trends
No full textNon-alcoholic fatty liver disease (NAFLD) is characterized by hepatic steatosis as the earliest manifestation and hallmark, and ranges from benign fatty liver to non-alcoholic steatohepatitis (NASH). Liver biopsy (LB) is considered the reference standard for NAFLD diagnosis, grading and characterization, but it is limited by its invasiveness and observer-dependence. Among imaging surrogates for the assessment of hepatic steatosis, MR is the most accurate. (1)H MR spectroscopy (MRS) provides a quantitative biomarker of liver fat content (LFC) called proton density fat fraction (PDFF), but it is time-consuming, not widely available and limited in sample size. Several MR imaging (MRI) techniques, in particular fat suppression and in-opposed phase techniques, have been used to quantify hepatic steatosis, mainly estimating LFC from water and fat signal intensities rather than proton densities. Several technical measures have been introduced to minimize the effect of confounding factors, in particular a low flip angle, a multiecho acquisition and a spectral modeling of fat with multipeak reconstruction to address respectively T1 effect, T2* effect, and the multifrequency interference effects of fat protons, allowing to use MRI to estimate LFC based on PDFF. Tang et al. evaluated MRI-estimated PDFF, obtained by applying the above-mentioned technical improvements, in the assessment of hepatic steatosis, using histopathology as the reference standard. The identification of PDFF thresholds, even though to be further explored and validated in larger and more diverse cohorts, is useful to identify steatosis categories based on MRI-based steatosis percentages. MRI, with the new refined techniques which provide a robust quantitative biomarker of hepatic steatosis (PDFF) evaluated on the whole liver parenchyma, is a promising non-invasive alternative to LB as the gold standard for steatosis diagnosis and quantification
Chronic periaortitis presenting with isolated pulmonary artery involvement: description of two cases
No full textMAGNETIC RESONANCE RADIOMIC ANALYSIS FOR THE PREDICTION OF GRAFT FAILURE IN PATIENTS WITH KIDNEY TRANSPLANTATION
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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
Post-transplantation hepatocellular carcinoma recurrence: Patterns and relation between vascularity and differentiation degree
Full text linkAim: To evaluate the relationship between hepatocellular carcinoma (HCC) vascularity and grade; to describe patterns and vascular/histopathological variations of post-transplantation recurrence. Methods: This retrospective study included 165 patients (143 men, 22 women; median age 56.8 years, range 28-70.4 years) transplanted for HCC who had a follow-up period longer than 2 mo. Pre-transplantation dynamic computed tomography or magnetic resonance examinations were retrospectively reviewed, classifying HCC imaging enhancement pattern into hypervascular and hypovascular based on presence of wash-in during arterial phase. All pathologic reports of the explanted livers were reviewed, collecting data about HCC differentiation degree. The association between imaging vascular pattern and pathological grade was estimated using the Fisher exact test. All follow-up clinical and imaging data were reviewed for evidence of recurrence. Recurrence rate was calculated and imaging features of recurrent tumor were collected, classifying early and late recurrences based on timing (< or ≥ 2 years after transplantation) and intrahepatic, extrahepatic and both intrahepatic and extrahepatic recurrences based on location. All intrahepatic recurrences were classified as hypervascular or hypovascular and the differentiation degree was collected where available. The presence of variations in imaging enhancement pattern and pathological grade between the primary tumor and the intrahepatic recurrence was evaluated and the association between imaging and histopatholgical variations was estimated by using the χ2 test. Results: Of the 163 patients with imaging evidence of viable tumor, 156 (95.7%) had hypervascular and 7 (4.3%) hypovascular HCC. Among the 125 patients with evidence of viable tumor in the explanted liver, 19 (15.2%) had grade 1, 56 (44.8%) grade 2, 40 (32%) grade 3 and 4 (3.2%) grade 4 HCC, while the differentiation degree was not assessable for 6 patients (4.8%). A significant association was found between imaging vascularity and pathological grade (P = 0.035). Post-transplantation recurrence rate was 14.55% (24/165). All recurrences occurred in patients who had a hypervascular primary tumor. Three patients (12.5%) experienced late recurrence; the location of the first recurrence was extrahepatic in 14 patients (58.3%), intrahepatic in 7 patients (29.2%) and both intrahepatic and extrahepatic in 3 patients (12.5%). Two patients had a variation in imaging characteristics between the primary HCC (hypervascular) and the intrahepatic recurrent HCC (hypovascular), while 1 patient had a variation of histopathological characteristics (from moderate to poor differentiation), however no association was found between imaging and histopathological variations. Conclusion: A correlation was found between HCC grade and vascularity; some degree of variability may exist between the primary and the recurrence imaging/histopathological characteristics, apparently not correlated
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
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