***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Purpose This study evaluated the effectiveness of  contrast-enhanced ultrasound ( CEUS ) , performed immediately after percutaneous ethanol injection ( PEI ) or radiofrequency thermal ablation ( RFTA ) , by comparing results with the computed tomography ( CT ) follow-up . Material s and methods Sixty-nine consecutive patients with a diagnosis of hepatocellular carcinoma ( HCC ) were included in this prospect i ve study . All patients underwent PEI or RFTA . After treatment , three CEUS enhancement patterns were observed : isovascular , hypovascular and avascular , which were compared with the CT findings . Sensitivity of the avascular pattern at CEUS and effectiveness of the ablative procedures were evaluated and compared with the chi-square test . Results Ninety hypervascular HCCs , with a mean diameter of 2.6 cm ( 0.5–4.9 cm ) , underwent PEI ( n=54 ) and RFTA ( n=36 ) . In the first group , CT identified complete necrosis in 28/54 ( 52 % ) lesions , 21 ( 75 % ) of which had avascular , one ( 4 % ) isovascular and six ( 21 % ) hypovascular patterns at CEUS . In the second group , CT showed complete necrosis in 31/36 ( 86 % ) lesions , all ( 100 % ) of which had a corresponding avascular pattern at CEUS . Sensitivity , specificity , positive predictive value , negative predictive value and accuracy of the avascular pattern at CEUS compared with CT findings were 75 % , 69 % , 72 % , 72 % and 72 % for PEI and 100 % , 20 % , 89 % , 100 % and 89 % , for RFTA , respectively . A statistically significant difference ( p<0.05 ) between the sensitivity of CEUS after PEI and after RFTA and between the necrosis obtained by RFTA and PEI were observed . Conclusions CEUS performed immediately after percutaneous ablation of hepatocellular carcinoma to evaluate treatment efficacy is compulsory in the case of RFTA but not for PEI.RiassuntoObiettiviStimare l’efficacia dell’ecografia con mezzo di contrasto ( CEUS ) eseguita immediatamente dopo iniezione percutanea di etanolo ( PEI ) o termoablazione con radiofrequenza ( RFTA ) , confront and o i risultati con la tomografia computerizzata ( TC ) di follow-up . Material i e metodiSessantanove pazienti consecutivi con diagnosi di epatocarcinoma ( HCC ) sono stati studiati prospetticamente . Le lesioni sono state trattate con PEI o RFTA . Sono stati descritti tre pattern di enhancement alla CEUS ( 1 , isovascolare ; 2 , ipovascolare ; 3 , avascolare ) e quindi confrontati con la TC di follow-up . La sensibilitá nel riconoscimento del pattern CEUS avascolare dopo PEI e RFTA e l’efficacia delle procedure ablative sono state valutate e confrontate tra loro con il test del gC2.RisultatiNovanta HCC ipervascolari , con diametro medio di 2,6 cm ( 0,5–4,9 cm ) , sono stati sottoposti a PEI ( 54 ) e RFTA ( 36 ) . Nel primo gruppo , la TC ha evidenziato necrosi completa in 28/54 ( 52 % ) lesioni , di cui 21 ( 75 % ) con pattern CEUS avascolare , 1 ( 4 % ) isovascolare e 6 ( 21 % ) ipovascolare . Nel secondo gruppo , la TC ha mostrato necrosi completa in 31/36 ( 86 % ) lesioni , tutte ( 100 % ) con pattern CEUS avascolare . Sensibilità , specificità , valore predittivo positivo e negativo ed accuratezza diagnostica per necrosi completa alla TC del pattern CEUS avascolare sono 75 % , 69 % , 72 % , 72 % e 72 % dopo PEI , 100 % , 20 % , 89 % , 100 % e 89 % dopo RFTA . La differenza tra la sensibilita della CEUS dopo PEI o RFTA e la differenza tra l’efficacia dei trattamenti è risultata statisticamente significativa ( p<0,05 ) . Conclusion iLa CEUS al termine della procedura ablativa dell’epatocarcinoma ai fini della valutazione del successo terapeutico è m and atoria dopo RFTA , ma non dopo PEI The purpose of this study was to assess the efficacy of conventional ultrasound ( US ) and contrast-enhanced ultrasound ( CEUS ) in guiding and assessing early therapeutic response to radiofrequency ( RF ) ablation for hepatocellular carcinomas ( HCCs ; up to 3 lesions , each ≤3 cm in diameter ) and to report the short-term follow-up results . Between September 2011 and January 2013 , 63 patients with 78 HCCs ( ≤3 cm ) underwent conventional US- and CEUS-guided percutaneous RF ablation .  CEUS was repeated after 20 - 30 min to assess therapeutic response , and local efficacy was further confirmed by contrast-enhanced magnetic resonance imaging ( MRI ) 1 mo after tumor ablation . Patients were followed periodically to look for local tumor or disease progression . Survival probability was estimated with the Kaplan-Meier method . Complete ablation was achieved for 76 ( 97.4 % ) of 78 HCCs in one ( n = 73 ) or two ( n = 3 ) sessions . No major complications were observed in any patient . The overall concordance in assessment of therapeutic efficacy of RF ablation between CEUS and MRI was 97.4 % ( 76/78 tumors ) . The concordance test gave a value of κ = 0.74 ( p < 0.001 ) , indicating that CEUS had a high diagnostic agreement with MRI . During a mean follow-up of 20 mo , the local tumor progression rate was 5.3 % ( 4/76 tumors ) . The 1- , 1.5- and 2-y cumulative survival rates were 98.4 % , 96.1 % and 92.6 % , respectively . Although CEUS has some intrinsic limitations , the combined use of conventional US and CEUS provides a safe and efficient tool to guide RF ablation for HCCs 3 cm or smaller , with encouraging results in terms of survival rate and minimal complications . Moreover , the immediate post-procedural CEUS can be a reliable alternative to contrast-enhanced MRI for assessing the early therapeutic response to RF ablation Abstract Background : Radiofrequency ablation ( RFA ) is increasingly used for the local destruction of unresectable hepatic malignancies . There is little information on its optimal approach or potential complications . Methods : Since late 1997 , we have undertaken 91 RFA procedures to ablate 231 unresectable primary or metastatic liver tumors in 84 patients .  RFA was performed via celiotomy ( n=39 ) , laparoscopy ( n=27 ) , or a percutaneous approach ( n=25 ) . Patients were followed with spiral computed tomographic ( CT ) scans at 1 to 2 weeks postprocedure and then every 3 months for 2 years . Results : Intraoperative ultrasound ( IOUS ) detected intrahepatic disease not evident on the preoperative scans of 25 of 66 patients ( 38 % ) undergoing RFA via celiotomy or laparoscopy . In 38 of 84 patients ( 45 % ) , RFA was combined with resection or cryosurgical ablation ( CSA ) , or both . RFA was used to treat an average of 2.8 lesions per patient , and the median size of treated lesions was 2 cm ( range , 0.3–9 cm ) . The average hospital stay was 3.6 days overall ( 1.8 days for percutaneous and laparoscopic cases ) . Ten patients underwent a second RFA procedure ( sequential ablations ) and , in one case , a third RFA procedure for large ( one patient ) , progressive ( seven patients ) , and /or recurrent ( three patients ) lesions . Seven ( 8 % ) patients had complications : one skin burn ; one postoperative hemorrhage ; two simple hepatic abscesses ; one hepatic abscess associated with diaphragmatic heat necrosis following sequential percutaneous ablations of a large lesion ; one postoperative myocardial infa rct ion ; and one liver failure . There were three deaths , one ( 1 % ) of which was directly related to the RFA procedure . Three of the complications , including one RFA-related death , occurred after percutaneous RFA . At a median follow-up of 9 months ( range , 1–27 months ) , 15 patients ( 18 % ) had recurrences at an RFA site , and 36 patients ( 43 % ) remained clinical ly free of disease . Conclusions : Celiotomy or laparoscopic approaches are preferred for RFA because they allow IOUS , which may demonstrate occult hepatic disease . Operative RFA also allows concomitant resection , CSA , or placement of a hepatic artery infusion pump , and isolation of the liver from adjacent organs . Percutaneous RFA should be reserved for patients at high risk for anesthesia , those with recurrent or progressive lesions , and those with smaller lesions sufficiently isolated from adjacent organs . Complications may be minimized when these approaches are applied selectively BACKGROUND AND OBJECTIVE Publication bias and other sample size effects are issues for meta-analyses of test accuracy , as for r and omized trials . We investigate limitations of st and ard funnel plots and tests when applied to meta-analyses of test accuracy and look for improved methods . METHODS Type I and type II error rates for existing and alternative tests of sample size effects were estimated and compared in simulated meta-analyses of test accuracy . RESULTS Type I error rates for the Begg , Egger , and Macaskill tests are inflated for typical diagnostic odds ratios ( DOR ) , when disease prevalence differs from 50 % and when thresholds favor sensitivity over specificity or vice versa . Regression and correlation tests based on functions of effective sample size are valid , if occasionally conservative , tests for sample size effects . Empirical evidence suggests that they have adequate power to be useful tests . When DORs are heterogeneous , however , all tests of funnel plot asymmetry have low power . CONCLUSION Existing tests that use st and ard errors of odds ratios are likely to be seriously misleading if applied to meta-analyses of test accuracy . The effective sample size funnel plot and associated regression test of asymmetry should be used to detect publication bias and other sample size related effects OBJECTIVE We investigated contrast-enhanced three-dimensional ultrasonography ( CE 3D US ) with contrast agent Sonazoid for evaluating the effect of percutaneous radiofrequency ( RF ) ablation  of hepatocellular carcinomas ( HCCs ) . METHODS 63 HCCs were treated by US-guided percutaneous RF ablation . CE 3D US after bolus injection of 0.2 mL of Sonazoid was performed 5 - 7 days before and 1 day after RF ablation . CE 3D computed tomography ( CT ) was performed 5 - 7 days before and 1 month after the ablation , and during the follow-up period . Multiplanar images in three orthogonal planes and US/CT angiograms were reconstructed on both modalities . Two blinded observers review ed the images on both modalities to evaluate the ablation effects . RESULTS After RF ablation , the evaluation on CE 3D US and that on CE 3D CT achieved concordance in 61 lesions . Among them , 59 lesions were detected with the absence of tumor vessels and tumor enhancement and evaluated as adequate ablation , and the remaining two lesions were detected with residual tumors . The kappa value for agreement between the findings on the two modalities was 0.65 . When 1-month CE 3D CT scans were used as reference st and ard , the sensitivity , specificity , and accuracy of 1-day CE 3D US for detecting adequate ablation were 97 % , 100 % , and 97 % , respectively . CONCLUSION By demonstrating the ablated areas and residual tumors in three dimensions , CE 3D US with Sonazoid was shown to be useful for evaluating the effect of RF ablation of HCCs , and there was good concordance with the results obtained by CE 3D CT PURPOSE To assess the utility of contrast-enhanced agent detection imaging ( ADI ) in the assessment of the therapeutic response to percutaneous radiofrequency ( RF ) ablation in patients with hepatocellular carcinoma ( HCC ) . MATERIAL S AND METHODS Ninety patients with a total of 97 nodular HCCs ( mean , 2.1+/-1.3 cm ; range , 1.0 - 5.0 cm ) treated with percutaneous RF ablation under the ultrasound guidance  were evaluated with contrast-enhanced ADI after receiving an intravenous bolus injection of a microbubble contrast agent ( SH U 508A ) . We obtained serial contrast-enhanced ADI images during the time period from 15 to 90 s after the initiation of the bolus contrast injection . All of the patients underwent a follow-up four-phase helical CT at 1 month after RF ablation , which was then repeated at 2 - 4 month intervals during a period of at least 12 months . The results of the contrast-enhanced ADI were compared with those of the follow-up CT in terms of the presence or absence of residual unablated tumor and local 
    Output:
    
Conclusion This study confirmed that CEUS exhibits high sensitivity and specificity in assessing therapeutic responses to RFA for liver tumors