***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: Abstract Objectives To prospect ively compare the diagnostic performance of ultrasound ( US ) , multidetector computed tomography ( MDCT ) and contrast-enhanced magnetic resonance imaging ( MRI ) in cirrhotic patients who were c and i date s for liver transplantation . Methods One hundred and forty consecutive patients with 163 hepatocellular carcinoma ( HCC ) nodules underwent US , MRI and MDCT .  Diagnosis of HCC was based on pathological findings or substantial growth at 12-month follow-up . Four different image data sets were evaluated : US , MDCT , MRI unenhanced and dynamic phases , MRI unenhanced dynamic and hepatobiliary phase .  Diagnostic accuracy , sensitivity , specificity , PPV and NPV , with corresponding 95 % confidence intervals , were determined . Statistical analysis was performed for all lesions and for three lesion subgroups ( < 1 cm , 1 - 2 cm , > 2 cm ) . Results Significantly higher diagnostic accuracy , sensitivity and NPV was achieved on dynamic + hepatobiliary phase MRI compared with US , MDCT and dynamic phase MRI alone . The specificity and PPV of US was significantly lower than that of MDCT , dynamic phase MRI and dynamic + hepatobiliary phase MRI . Similar results were obtained for all sub-group analyses , with particular benefit for the diagnosis of smaller lesions between 1 and 2 cm . Conclusions Dynamic + hepatobiliary phase MRI improved detection and characterisation of HCC  in cirrhotic patients . The greatest benefit is for diagnosing lesions between 1 and 2 cm . Key Points• US , CT and MRI can all identify HCC in cirrhotic patients • US has good sensitivity but suffers from false-positive findings • Dynamic CT and MR have similar diagnostic performance for diagnosing HCC • Dynamic + hepatobiliary phase MRI significantly improves detection and characterisation of HCC • The greatest benefit is for the diagnosis of lesions between 1 and 2 PURPOSE To compare two different injection rates for gadoxetic acid-enhanced hepatic arterial phase images on hepatic dynamic MRI . MATERIAL S AND METHODS Hepatic arterial phase images were obtained after an intravenous bolus injection of gadoxetic acid at a rate of 1 mL/second in 62 patients and 2 mL/second in 64 patients on a 3 Tesla MR scanner using a test-bolus injection method . The signal-to-noise ratios ( SNR ) of the liver , portal vein , hepatic vein , aorta , spleen and pancreas were measured . The contrast-to-noise ratio ( CNR ) of hypervascular hepatic tumors was calculated . Two radiologists independently scored items to evaluate image quality of hepatic arterial phase and detected hypervascular hepatocellular carcinoma ( HCC ) . RESULTS The SNR of the aorta on the arterial phase images was significantly higher in the 1 mL/second group ( 235.43 + /- 82.59 ) than in the 2 mL/second group ( 190.94 + /- 96.90 , P < 0.05 ) . The SNRs of the liver , spleen and pancreas , the CNRs of hypervascular hepatic tumors , the detection rate of hypervascular HCC and subjective ratings for the optimal arterial enhancement were comparable between the two groups . CONCLUSION Injection rates of 2 mL/second and 1 mL/second provided comparable image qualities on arterial phase images of hepatic dynamic MRI using gadoxetic acid BACKGROUND & AIMS To prospect ively assess the diagnostic accuracy of the incorporation of additional magnetic resonance imaging ( MRI ) parameters in those based on contrast enhancement pattern for the diagnosis of solitary nodules between 5 and 20 mm , detected during surveillance in patients with cirrhosis . METHODS Between November 2003 and January 2010 , we prospect ively included 159 cirrhotic patients with a newly detected solitary nodule between 5 and 20 mm in diameter by screening ultrasonography ( US ) . Hepatic MRI and fine-needle biopsy were performed in all patients . RESULTS Final diagnoses were hepatocellular carcinoma ( HCC ) ( n=103 ) , other malignant lesions ( intrahepatic cholangiocarcinoma/metastases ) ( n=4 ) , and benign lesions ( n=52 ) . The specific enhancement pattern ( arterial enhancement followed by washout ) yielded a sensitivity and specificity of 58.3 % and 96.4 % , respectively . Peritumoral capsule was present in 43 HCC and in 2 non-HCC lesions . Intralesional fat was detected in 24 nodules ; 5 nodules were non-HCC . Finally , the presence of both capsule and fat was observed in 10 cases , all of them HCC ( 100 % specificity ) , but all of them also displayed the specific enhancement pattern , thus adding no sensitivity or specificity . CONCLUSIONS Conclusive non-invasive diagnosis of HCC in cirrhosis should be based only on the contrast enhancement pattern , while other characteristics at MRI do not increase the diagnostic accuracy PURPOSE To prospect ively compare gadoxetate disodium-enhanced magnetic resonance ( MR ) imaging with multiphasic 64-section multidetector computed tomography ( CT ) in the detection of hepatocellular carcinoma ( HCC ) in patients with cirrhosis . MATERIAL S AND METHODS Institutional review board approval and informed patient consent were obtained for this prospect i ve study . Fifty-eight patients ( 39 men , 19 women ; mean age , 63 years ; age range , 35 - 84 years ) underwent gadoxetate disodium-enhanced MR imaging and multiphasic 64-section multidetector CT .  The imaging examinations were performed within 30 days of each other . The two sets of images were qualitatively analyzed in r and om order by three independent readers in a blinded and retrospective fashion . Using strict diagnostic criteria for HCC , readers classified all detected lesions with use of a four-point confidence scale . The reference st and ard was a combination of pathologic proof , conclusive imaging findings , and substantial tumor growth at follow-up CT or MR imaging ( range of follow-up , 90 - 370 days ) . The diagnostic accuracy , sensitivity , and positive predictive value were compared between the two image sets . Interreader variability was assessed . The accuracy of each imaging method was determined by using an adjusted modified chi(2 ) test . RESULTS Eighty-seven HCCs ( mean size + /- st and ard deviation , 1.8 cm + /- 1.5 ; range , 0.3 - 7.0 cm ) were confirmed in 42 of the 58 patients . Regardless of lesion size , the average diagnostic accuracy and sensitivity for all readers were significantly greater with gadoxetate disodium-enhanced MR imaging ( average diagnostic accuracy : 0.88 , 95 % confidence interval [ CI ] : 0.80 , 0.97 ; average sensitivity : 0.85 , 95 % CI : 0.74 , 0.96 ) than with multidetector CT ( average diagnostic accuracy : 0.74 , 95 % CI : 0.65 , 0.82 ; average sensitivity : 0.69 , 95 % CI : 0.59 , 0.79 ) ( P < .001 for each ) . No significant difference in positive predictive value was observed between the two image sets for each reader . Interreader agreement was good to excellent . CONCLUSION Compared with multiphasic 64-section multidetector CT , gadoxetate disodium-enhanced MR imaging yields significantly higher diagnostic accuracy and sensitivity in the detection of HCC in patients with cirrhosis BACKGROUND & AIMS To determine the optimal imaging scan or combinations in terms of diagnostic performance and re source utilization for 1 - 2 cm nodules found on surveillance for hepatocellular carcinoma . METHODS Eighty-four cirrhotic patients with 101 , 1 - 2 cm nodules ( 34 malignant , 67 non-malignant ) prospect ively underwent st and ardized contrast-enhanced ultrasound , CT , and MRI scans .  Sensitivity/specificity and potential imaging/biopsy utilization of individual imaging modalities and two-modality combinations performed at the same time ( coincidental ) or in sequence were measured . Final diagnosis was determined by biopsy ( 23 ) , growth ( 10 ) , recurrence ( 1 ) , or stability in size for ≥ 18 months ( 67 ) . RESULTS For single imaging scans , sensitivities/specificities ranged between 53 - 62 % and 91 - 100 % . When two scans were combined requiring both to be positive , sensitivities/specificities ranged between 29 - 41 % and 99 - 100 % . When two scans were combined sequentially , requiring only one to be positive , sensitivities/specificities ranged between 74 - 89 % and 91 - 99 % . When comparing combination of two positive tests ( MRI and CT ) to MRI alone , there was a significant drop in sensitivity ( 41 % vs. 62 % , p=0.02 ) , no change in specificity ( both 100 % ) , with twice as many scans performed , and 9 % rise in potential biopsies or 7 % rise in follow-up scans . When comparing the combination of MRI then CT ( if MRI negative ) to MRI alone , there was an insignificant rise in sensitivity ( 74 % vs. 62 % , p=0.13 ) , drop in specificity ( 97 % vs. 100 % ) , with 77 % more scans performed , and 6 % drop in potential biopsies or 7 % drop in potential follow-up scans . CONCLUSIONS Single imaging scans have similar specificity to two coincidental positive scans with much less re source utilization . Sequential imaging provides the best sensitivity but with diminished specificity Objective To prospect ively assess the additional value of the hepatobiliary ( HB ) phase of Gd-EOB-DTPA-MRI in identifying and characterising small ( ≤2 cm ) hepatocellular carcinomas ( HCCs ) undetermined in dynamic phases alone because of their atypical features , according to the AASLD criteria . Methods 127 cirrhotic patients were evaluated with Gd-EOB-DTPA-MRI in two sets : unenhanced and dynamic phases ; unenhanced , dynamic and HB phases . Sixty-two out of 215 nodules ( 29 % ) were atypical in 42 patients ( 33 % ) . Results 62 atypical nodules were reported at histology : high- grade dysplastic nodules (HGDN)/early HCC ( n = 20 ) , low- grade DN ( LGDN ) ( n = 21 ) , regenerative nodules ( n = 17 ) and nodular regenerative hyperplasia ( n = 4 ) . The sensitivity , specificity , accuracy , positive and negative predictive value ( PPV , NPV ) were increased by the addition of the HB phase : 88.4–99.4 % , 88–95 % , 88–98.5 % , 97–99 % , and 65–97.5 % , respectively . Twenty atypical nodules were malignant ( 32 % ) , 19 of which were characterised only during the HB phase . Conclusions The HB phase is 11 % more sensitive in the classification of HGDN/early HCC than dynamic MRI , with an added value of 32.5 % in the NPV . The high incidence ( 33 % ) of atypical nodules and their frequent malignancy ( 32 % ) suggest the widespread employment of Gd-EOB-DTPA-MRI in the follow-up of small nodules ( ≤2 cm ) in cirrhosis In a prospect i ve study , we examined the impact of arterial hypervascularity , as established by the European Association for the Study of the Liver ( EASL ) recommendations , as a criterion for characterizing small ( 1‐3 cm ) nodules in cirrhosis . A total of 72 nodules ( 1‐2 cm , n = 41 ; 2.1‐3 cm , n = 31 ) detected by ultrasonography in 59 patients with cirrhosis were included in the study . When coincidental arterial hypervascularity was detected at contrast perfusional ultrasonography and helical computed tomography , the lesion was considered to be hepatocellular carcinoma ( HCC ) according to EASL criteria . When one or both techniques showed negative results , ultrasound‐guided biopsy was performed . In cases with negative results for malignancy or high‐ grade dysplasia , biopsy was repeated when an increase in size was detected at the 3‐month follow‐up examination . Coincidental hypervascularity was found in 44 of 72 nodules ( 61 % ; 44 % of 1‐2‐cm nodules and 84 % of 2‐3‐cm nodules ) . Fourteen nodules ( 19.4 % ) had negative results with both techniques ( hypovascular nodules ) . Biopsy showed HCC in 5 hypovascular nodules and in 11 of 14 nodules with hypervascularity using only one technique . All nodules larger than 2 cm finally result ed to be HCC . Not satisfying the EASL imaging criteria for diagnosis were 38 % of HCCs 1 to 2 cm ( 17 % hypovascular ) and 16 % of those 2 to 3 cm ( none hypovascular ) . In conclusion , the noninvasive EASL criteria for diagnosis of HCC are satisfied in only 61 % of 
    Output:
    
In conclusion , Gd-EOB-DTPA-enhanced MRI  demonstrated higher sensitivity and overall diagnostic accuracy than MDCT , and thus should be the preferred imaging modality for diagnosing small HCCs measuring up to 2 cm .