A training program for primary care physicians improves the effectiveness of ultrasound surveillance of hepatocellular carcinoma.

BACKGROUND AND AIMS: Cirrhosis is the main risk factor of hepatocellular carcinoma (HCC), but only a minority of cirrhotic patients are referred to the hepatologist by primary care physicians (PCP) and receive regular ultrasound surveillance. The aim of this study was to determine whether a training program targeted to PCP could enhance the effectiveness of surveillance in a real-life setting. PATIENTS AND METHODS: A total of 120 PCP in an Italian area with a high incidence of HCC were trained to identify cirrhotic patients, to refer them to the Hepatology Centers of the area, and to start regular ultrasound surveillance. Clinical characteristics, outcome of treatments, and survival of 190 consecutive HCC patients in the same centers after training were compared with 244 HCC referred from the same area before training, and to 232 HCC referred by untrained PCP from other areas. RESULTS: Trained PCP referred significantly more HCC patients detected under surveillance and at an early stage (Barcelona Clinic Liver Cancer-A), suitable for radical treatments. In the intervention area, the 3 and 5-year survival of HCC patients increased after training from 35 to 48% and from 20 to 40%, respectively (P<0.05). In contrast, survival was unchanged in the other areas. At multivariate analysis, independent predictors adversely affecting survival were Child-Pugh B-C, α-fetoprotein more than 10 ng/dl, nonviral etiology, intermediate/advanced Barcelona Clinic Liver Cancer stage, and referral by an untrained PCP. CONCLUSION: Specific training of PCP aimed at the identification and referral of cirrhotic patients efficiently improves HCC survival.

Head-to-head comparison of transient elastography (TE), real-time tissue elastography (RTE), and acoustic radiation force impulse (ARFI) imaging in the diagnosis of liver fibrosis.

BACKGROUND: Real-time tissue elastography (RTE), acoustic radiation force impulse (ARFI) imaging, and transient elastography (TE) are new technologies that are used for liver stiffness evaluation. The aim of this study was to compare these methods in the same population and to determine their diagnostic accuracy in the prediction of liver fibrosis. METHODS: Forty-five consecutive, previously biopsied, patients with chronic liver disease and 27 normal subjects underwent TE, RTE, and ARFI on the right liver lobe. Correlation coefficients between measurements, Metavir fibrosis stage, and histological necro-inflammatory activity (adjusted for fibrosis stage) were evaluated via Spearman's rank order correlation coefficients. Areas under the receiver operating characteristic curve (AUROCs) were calculated to predict each fibrosis stage. RESULTS: Failure or inconsistent results occurred in 12.5% of the attempts at TE, but in none of the attempts at RTE and ARFI. The three methods showed high correlation with fibrosis and poor correlation with necro-inflammatory activity. TE and ARFI exhibited high diagnostic accuracy (AUROCs ≥0.9) in diagnosing cirrhosis (F4 Metavir). All three methods presented fair (AUROCs >0.7) to good (AUROCs >0.8) diagnostic accuracy in diagnosing fibrosis (F1-4 Metavir) and significant fibrosis (F2-4 Metavir), with TE showing the best performance (AUROCs were 0.878 for fibrosis and 0.897 for significant fibrosis). CONCLUSIONS: TE and ARFI provide high diagnostic accuracy in the diagnosis of cirrhosis. When feasible, TE may perform better than RTE and ARFI in predicting fibrosis and significant fibrosis, but larger studies are needed.

Novel Helmholtz-based photoacoustic sensor for trace gas detection at ppm level using GaInAsSb/GaAlAsSb DFB lasers.

A new and compact photoacoustic sensor for trace gas detection in the 2-2.5 microm atmospheric window is reported. Both the development of antimonide-based DFB lasers with singlemode emission in this spectral range and a novel design of photoacoustic cell adapted to the characteristics of these lasers are discussed. The laser fabrication was made in two steps. The structure was firstly grown by molecular beam epitaxy then a metallic DFB grating was processed. The photoacoustic cell is based on a Helmholtz resonator that was designed in order to fully benefit from the highly divergent emission of the antimonide laser. An optimized modulation scheme based on wavelength modulation of the laser source combined with second harmonic detection has been implemented for efficient suppression of wall noise. Using a 2211 nm laser, sub-ppm detection limit has been demonstrated for ammonia.

Application of antimonide diode lasers in photoacoustic spectroscopy.

First investigations of photoacoustic (PA) spectroscopy (PAS) of methane using an antimonide semiconductor laser are reported. The laser fabrication is made in two steps. The structure is firstly grown by molecular beam epitaxy, then a metallic distributed-feedback (DFB) grating is processed. The laser operates at 2371.6 nm in continuous wave and at room temperature. It demonstrates single-mode emission with typical tuning coefficients of 0.04 nm mA(-1) and 0.2 nm K(-1). PA detection of methane was performed by coupling this laser into a radial PA cell. A detection limit of 20 ppm has been achieved in a preliminary configuration that was not optimised for the laser characteristics.