***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: Background In humans with normal hearts multi-slice computed tomography ( MSCT ) based volumetry was shown to correlate well with the gold st and ard , cardiac magnetic resonance imaging ( CMR ) . We correlated both techniques in patients with various degrees of heart failure and reduced ejection fraction ( HFREF ) result ing from cardiac dilatation . Methods Twenty-four patients with a left ventricular end-diastolic volume ( LV-EDV ) of ≥ 150 ml measured by angiography underwent MSCT and CMR scanning for left and right ventricular ( LV , RV ) volumetry . MSCT based short cardiac axis views were obtained beginning at the cardiac base advancing to the apex . These were reconstructed in 20 different time windows of the RR-interval ( 0–95 % ) serving for identification of enddiastole ( ED ) and end-systole ( ES ) and for planimetry . ED and ES volumes and the ejection fraction ( EF ) were calculated for LV and RV . MSCT based volumetry was compared with CMR . Results MSCT based LV volumetry significantly correlates with CMR as follows : LV-EDV r = 0.94 , LV-ESV r = 0.98 and LV-EF r = 0.93 , but significantly overestimates LV-EDV and LV-ESV and underestimates EF ( P < 0.0001 ) . MSCT based RV volumetry significantly correlates with CMR as follows : RV-EDV r = 0.79 , RV-ESV r = 0.78 and RV-EF r = 0.73 , but again significantly overestimates RV-EDV and RV-ESV and underestimates RV-EF ( P < 0.0001 ) . Conclusion When compared with CMR a continuous overestimation of volumes and underestimation of EF needs to be considered when applying MSCT in HFREF patients Background Right ventricular ( RV ) function is a powerful predictor of survival in patients with pulmonary hypertension ( PH ) , but noninvasively assessing RV function remains a challenge . The aim of this study was to prospect ively compare gated 18F-fluorodeoxyglucose positron emission tomography ( 18F-FDG PET ) myocardial imaging ( gated PET ) , cardiac magnetic resonance ( CMR ) , and cardiac computed tomography ( CCT ) for the assessment of RV volume and ejection fraction in patients with PH . Methods Twenty-three consecutive patients aged more than 16 years diagnosed with PH were included . All patients underwent gated PET , CMR , and CCT within 7 days . Right ventricular end-diastolic volume ( RVEDV ) , right ventricular end-systolic volume ( RVESV ) , and right ventricular ejection fraction ( RVEF ) were calculated by three imaging modalities . RV 18F-FDG uptake was determined as RV-corrected st and ardized uptake value ( SUV ) , and the ratio of RV to left ventricular (LV)-corrected SUV ( Corrected SUV R/L ) . Results Gated PET showed a moderate correlation ( r = 0.680 , P < .001 ) for RVEDV , good correlation for RVESV ( r = 0.757 , P < .001 ) and RVEF ( r = 0.788 , P < .001 ) with CMR , and good correlation for RVEDV ( r = 0.767 , P < .001 ) , RVESV ( r = 0.837 , P < .001 ) , and RVEF ( r = 0.730 , P < .001 ) with CCT . Bl and -Altman analysis revealed systematic underestimation of RVEDV and RVESV and overestimation of RVEF with gated PET compared with CMR and CCT . The correlation between RVESV ( r = 0.863 , P < .001 ) , RVESV ( r = 0.903 , P < .001 ) , and RVEF ( r = 0.853 , P < .001 ) of CMR and those of CCT was excellent ; Bl and -Altman analysis showed only a slight systematic variation between CMR and CCT . There were statistically significant negative correlations between RV-corrected SUV and RVEF-CMR ( r = −0.543 , P < .01 ) , Corrected SUV R/L and RVEF-CMR ( r = −0.521 , P < .05 ) , RV-corrected SUV and RVEF-CCT ( r = −0.429 , P < .05 ) , Corrected SUV R/L and RVEF-CCT ( r = −0.580 , P < .01 ) , respectively . Conclusion Gated PET had moderate-to-high correlation with CMR and CCT in the assessment s of RV volume and ejection fraction . It is an available method for simultaneous assessing of RV function and myocardial glucose metabolism in patients with PH In clinical measurement comparison of a new measurement technique with an established one is often needed to see whether they agree sufficiently for the new to replace the old . Such investigations are often analysed inappropriately , notably by using correlation coefficients . The use of correlation is misleading . An alternative approach , based on graphical techniques and simple calculations , is described , together with the relation between this analysis and the assessment of repeatability BACKGROUND Cardiac magnetic resonance ( CMR ) accurately quantifies right ventricular ( RV ) and left ventricular ( LV ) volumes and function . Limited availability of CMR and increasing use of MR-incompatible cardiovascular devices underscore the potential utility of cardiac computed tomography ( CT ) for ventricular quantification . This study quantified biventricular size and systolic function with multi-detector row CT compared with CMR imaging . METHODS Twenty-six subjects prospect ively underwent CT and CMR examinations on a 16-detector CT and 1.5 T MR scanner , respectively ; claustrophobia in one and nongated CT imaging in another precluded complete imaging in 2 subjects . Contiguous multiphase short-axis images were generated from axial CT data , and steady-state free precession cine MR produced contiguous short-axis cines . Semiautomated software generated ventricular borders to calculate volume , mass , and ejection fraction ( EF ) from both sets of images . Blinded observers completed quantification and wall motion analyses of 23 CMR and CT data sets independently . RESULTS All measures of LV size and function by cardiac CT correlated well with CMR over a wide range of LV function ( LVEF 30%-72 % by CMR ) , including end-diastolic volume ( r = 0.97 ) , end-systolic volume ( r = 0.97 ) , EF ( r = 0.97 ) , and mass ( r = 0.95 ) . Of 24 cases , 6 had inadequate contrast opacification of the RV precluding RV segmentation . In the remaining 18 CMR-CT data pairs , RVEF showed moderate agreement ( r = 0.86 ) , and RV volumes correlated well ( r = 0.97 and 0.94 for RV end-diastolic volume and RV end-systolic volume , respectively ) . Ten percent of LV segments visualized by CT were inadequate for wall motion assessment due to motion artifact or inadequate contrast between myocardium and endocardium . For segments adequately visualized by both techniques , the mean kappa statistic was 0.88 ( range 0.78 - 1.0 ) , consistent with good agreement . CONCLUSION Cardiac CT accurately quantifies LV size and function ; RV quantification with cardiac CT requires optimized contrast opacification of the RV OBJECTIVES We sought to study the relationship between survival and right ventricular ejection fraction ( RVEF ) in a subgroup of patients with moderate congestive heart failure ( CHF ) . BACKGROUND It has been demonstrated that RVEF is an independent predictor of survival in patients with advanced CHF . METHODS Cardiopulmonary exercise testing and radionuclide angiography ( to determine right and left ventricular ejection fraction ) were prospect ively performed in 205 consecutive patients with moderate CHF ( 140 patients in New York Heart Association [ NYHA ] class II , 65 in class III ) . RESULTS Left ventricular ejection fraction was 29.3%+/-10.1 % , RVEF was 37.5%+/-14.6 % and peak oxygen consumption ( VO2 ) was 16.2+/-5.4 ml/min/kg ( 60.2%+/-19 % of maximal predicted VO2 ) . After a median follow-up period of 755 days , there were 44 cardiac-related deaths , 3 deaths from noncardiac causes and 15 transplantations of whom 2 were urgent ; 1 patient was lost to follow-up . Multivariate analysis showed that three variables-NYHA classification , percent of maximal predicted VO2 and RVEF-were independent predictors of both survival and event-free cardiac survival . Left ventricular ejection fraction and peak VO2 normalized to body weight had no predictive value . The event-free survival rates from cardiovascular mortality and urgent transplantation at 1 year were 80 % , 90 % and 95 % in patients with an RVEF < 25 % , with a RVEF > or = 25 % and < 35 % and with a RVEF > or = 35 % , respectively . At 2 years , survival rates were 59 % , 77 % and 93 % in the same subgroups , respectively . CONCLUSIONS In addition to the NYHA classification and to the percent of maximal predicted VO2 , RVEF is an independent predictor of survival in patients with moderate CHF BACKGROUND This study prospect ively compared the accuracy of a sixty-four slice multidetector row CT ( 64-MDCT ) in cardiac magnetic resonance imaging ( MRI ) for the assessment of right ventricular ( RV ) dysfunction and  dilatation in patients with mitral regurgitation . METHODS Eighty-four patients underwent ECG-gated 64-MDCT for the assessment of RV dysfunction and dilatation ; 54 of these patients had known mitral regurgitation .  End-diastolic and end-systolic volumes , stroke volume , and ejection fraction were measured using the 64-MDCT , and these results were retrospectively compared to the results of MRI ( reference st and ard ) . Agreement between the 64-MDCT and MRI results was investigated using linear regression and Bl and -Altman analyses . Receiver operating characteristic analyses calculated the sensitivity and specificity of RV dilatation on 64-MDCT scans for the prediction of mitral regurgitation severity and dysfunction , respectively . RESULTS No significant differences in RV function parameters were calculated between 64-MDCT and MRI ( r=0.87 to 0.94 ; all p<0.001 ) . Good intertechnique agreement was obtained using linear regression and Bl and -Altman analyses . ROC analyses revealed that RV enlargement ( > 33 mm ) on 64-MDCT scans predicted the RV dysfunction of mitral regurgitation with a sensitivity of 92.9 % and a specificity of 82.9 % . CONCLUSIONS ECG-gated 64-MDCT accurately and reliably assessed RV function in patients with and without mitral regurgitation . Moreover , the presence of RV dilatation on the 64-MDCT scan assisted in the prediction of RV dysfunction and mitral regurgitation severity OBJECTIVE To prospect ively evaluate the accuracy of left and right ventricular function and myocardial mass measurements based on a dual-step , low radiation dose protocol with prospect ively ECG-triggered 2nd generation dual- source CT ( DSCT ) , using cardiac MRI ( cMRI ) as the reference st and ard . MATERIAL S AND METHODS Twenty patients underwent 1.5 T cMRI and prospect ively ECG-triggered dual-step pulsing cardiac DSCT .  This image acquisition mode performs low-radiation ( 20 % tube current ) imaging over the majority of the cardiac cycle and applies full radiation only during a single adjustable phase . Full-radiation-phase images were used to assess cardiac morphology , while low-radiation-phase images were used to measure left and right ventricular function and mass . Quantitative CT measurements based on contiguous multiphase short-axis reconstructions from the axial CT data were compared with short-axis SSFP cardiac cine MRI . Contours were manually traced around the ventricular borders for calculation of left and right ventricular end-diastolic volume , end-systolic volume , stroke volume , ejection fraction and myocardial mass for both modalities . Statistical methods included independent t-tests , the Mann-Whitney U test , Pearson correlation statistics , and Bl and -Altman analysis . RESULTS All CT measurements of left and right ventricular function and mass correlated well with those from cMRI : for left/right end-diastolic volume r=0.885/0.801 , left/right end-systolic volume r=0.947/0.879 , left/right stroke volume r=0.620/0.697 , left/right ejection fraction r=0.869/0.751 , and left/right myocardial mass r=0.959/0.702 . Mean radiation dose was 6.2±1.8mSv . CONCLUSIONS Prospect ively ECG-triggered , dual-step pulsing cardiac DSCT accurately quantifies left and right ventricular function and myocardial mass in comparison with cMRI with substantially lower radiation exposure than reported for traditional retrospective ECG-g 
    Output:
    
Conclusion CT can assess RVF with accuracy comparable to that of MRI .
Thus , CT is a valid alternative to MRI.Key Points• CT could help clinicians to assess RVF as accurately as MRI can , with satisfactory repeatability