***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 —Both whole-heart magnetic resonance coronary angiography ( WH-MRCA ) and multidetector computed tomography ( MDCT ) have been proposed for the noninvasive identification of the coronary stenosis . The authors sought to directly compare the diagnostic accuracy of these noninvasive imaging techniques using the invasive quantitative coronary angiography as a reference st and ard . Methods and Results —Seventy-seven consecutive patients ( 56 men , 61±14 years ) prospect ively underwent  WH-MRCA and 40- or 64-slice MDCT before the quantitative coronary angiography .  Diagnostic accuracy of WH-MRCA and MDCT for the visual identification of > 50 % diameter stenosis in segments of > 1.5 mm size was compared using the quantitative coronary angiography as a reference . According to the quantitative coronary angiography , 49 of 992 coronary segments > 1.5 mm diameter had > 50 % diameter stenosis . MDCT had a higher success rate ( 100 % versus 88 % , P<0.001 ) and enabled identification of more segments ( 963 versus 726 , P<0.001 ) than did WH-MRCA . On a per-segment basis , WH-MRCA had similar sensitivity ( 47/49 or 96 % versus 48/49 or 98 % , P=0.9 ) but significantly lower specificity ( 644/943 or 68 % versus 863/943 or 92 % , P<0.001 ) and accuracy ( 691/992 or 70 % versus 911/992 or 92 % , P<0.001 ) for the detection of > 50 % diameter stenosis  than did MDCT . On a per-patient basis , the sensitivity was similar ( 17/17 or 100 % versus 16/17 or 94 % , P=0.9 ) , but specificity ( 43/60 or 72 % versus 53/60 or 88 % , P=0.024 ) and diagnostic accuracy ( 60/77 or 78 % , versus 69/77 or 90 % , P=0.044 ) of WH-MRCA for the detection of > 50 % diameter stenosis were significantly lower than of MDCT . Conclusions —Because of the higher success rate and higher number of interpretable segments , 40- or 64-slice MDCT performs better than WH-MRCA Objectives We evaluated the potential of prospect ively ECG-triggered high-pitch spiral acquisition with low tube voltage and current in combination with iterative reconstruction to achieve coronary CT angiography with sufficient image quality at an effective dose below 0.1 mSv . Methods Contrast-enhanced coronary dual source CT angiography ( 2 × 128 × 0.6 mm , 80 kV , 50 mAs ) in prospect ively ECG-triggered high-pitch spiral acquisition mode was performed in 21 consecutive individuals ( body weight < 100 kg , heart rate ≤60/min ) . Images were reconstructed with raw data -based filtered back projection ( FBP ) and iterative reconstruction ( IR ) . Image quality was assessed on a 4-point scale ( 1 = no artefacts , 4 = unevaluable ) . Results Mean effective dose was 0.06 ± 0.01 mSv . Image noise was significantly reduced in IR ( 128.9 ± 46.6 vs. 158.2 ± 44.7 HU ) . The mean image quality score was lower for IR ( 1.9 ± 1.1 vs. 2.2 ± 1.0 , P < 0.0001 ) . Of 292 coronary segments , 55 in FBP and 40 in IR ( P = 0.12 ) were grade d “ unevaluable ” . In patients with a body weight ≤75 kg , both in FBP and in IR , the rates of fully evaluable segments were significantly higher in comparison to patients > 75 kg . Conclusions Coronary CT angiography with an estimated effective dose < 0.1 mSv may provide sufficient image quality in selected patients through the combination of high-pitch spiral acquisition and raw data -based iterative reconstruction . Key Points• Coronary CT angiography with an estimated effective dose < 0.1 mSv is possible.• Combination of high-pitch spiral acquisition with iterative reconstruction achieves sufficient image quality .• Diagnostic accuracy remains to be assessed in future trials Background —Whole-heart coronary magnetic resonance angiography ( MRA ) is a promising method for noninvasive , radiation-free detection and exclusion of obstructive coronary artery disease ; however , the required imaging time and robustness of the technique are not yet satisfactory . We evaluated the value of whole-heart coronary MRA at 3.0 T using a 32-channel cardiac coil , which reduces image-acquisition times and hence allows to increase the clinical throughput . Methods and Results —A total of 110 consecutive patients with suspected coronary artery disease referred for clinical ly indicated conventional coronary angiography  were included in this prospect i ve study . Acquisition of 3.0 T coronary MRA data was done by using 32-channel receiver coils . An ECG-triggered , navigator-gated , inversion-recovery prepared , segmented gradient-echo sequence was used for image acquisition with an acceleration factor of 3 in the phase-encoding direction using generalized auto calibrating partially parallel acquisitions reconstruction . Acquisition of coronary MRA was successfully completed in 101 of 110 ( 92 % ) patients with average imaging time of 7.0±1.8 minutes . The sensitivity , specificity , positive and negative predictive value of coronary MRA on a patient-based analysis were 95.9 % ( 47/49 , 95 % CI , 86.0%–99.4 % ) , 86.5 % ( 45/52 , 95 % CI , 74.2%–94.4 % ) , 87.0 % ( 47/54 , 95 % CI , 75.1%–94.6 % ) and 95.7 % ( 45/47 , 95 % CI , 85.4%–99.4 % ) , respectively . Conclusions —Whole-heart coronary MRA at 3.0 T using a 32-channel cardiac coil allows high overall accuracy for detecting significant coronary artery disease with reduced imaging time . It has potential to be a robust and alternative technique for ruling out significant coronary artery disease . Clinical Trial Registration —URL : http://www.chictr.org . Unique identifier : ChiCTR-DDT-07000121 Summary Background In patients with suspected coronary heart disease , single-photon emission computed tomography ( SPECT ) is the most widely used test for the assessment of myocardial ischaemia , but its diagnostic accuracy is reported to be variable and it exposes patients to ionising radiation . The aim of this study was to establish the diagnostic accuracy of a multiparametric cardiovascular magnetic resonance ( CMR ) protocol with x-ray coronary angiography as the reference st and ard , and to compare CMR with SPECT , in patients with suspected coronary heart disease . Methods In this prospect i ve trial patients with suspected angina pectoris and at least one cardiovascular risk factor were scheduled for CMR , SPECT , and invasive x-ray coronary angiography . CMR consisted of rest and adenosine stress perfusion , cine imaging , late gadolinium enhancement , and MR coronary angiography . Gated adenosine stress and rest SPECT used 99mTc tetrofosmin . The primary outcome was diagnostic accuracy of CMR  . This trial is registered at controlled-trials.com , number IS RCT N77246133 . Findings In the 752 recruited patients , 39 % had significant CHD as identified by x-ray angiography . For multiparametric CMR the sensitivity was 86·5 % ( 95 % CI 81·8–90·1 ) , specificity 83·4 % ( 79·5–86·7 ) , positive predictive value 77·2 % , ( 72·1–81·6 ) and negative predictive value 90·5 % ( 87·1–93·0 ) . The sensitivity of SPECT was 66·5 % ( 95 % CI 60·4–72·1 ) , specificity 82·6 % ( 78·5–86·1 ) , positive predictive value 71·4 % ( 65·3–76·9 ) , and negative predictive value 79·1 % ( 74·8–82·8 ) . The sensitivity and negative predictive value of CMR and SPECT differed significantly ( p<0·0001 for both ) but specificity and positive predictive value did not ( p=0·916 and p=0·061 , respectively ) . Interpretation CE-MARC is the largest , prospect i ve , real world evaluation of CMR and has established CMR 's high diagnostic accuracy in coronary heart disease and CMR 's superiority over SPECT . It should be adopted more widely than at present for the investigation of coronary heart disease . Funding British Heart Foundation OBJECTIVES This national multicenter study determined the diagnostic performance of 1.5-T whole-heart coronary magnetic resonance angiography ( MRA ) in patients with suspected coronary artery disease ( CAD ) . BACKGROUND Whole-heart coronary MRA using steady-state free precession allows noninvasive detection of CAD without the administration of contrast medium . However , the accuracy of this approach has not been determined in a multicenter trial . METHODS Using a 1.5-T magnetic resonance imaging unit , free-breathing steady-state free precession whole-heart coronary MRA images were acquired for 138 patients with suspected CAD at 7 hospitals . The accuracy of MRA for detecting a ≥ 50 % reduction in diameter was determined using X-ray coronary angiography as the reference method . RESULTS Acquisition of whole-heart coronary MRA images was performed in 127 ( 92 % ) of 138 patients with an average imaging time of 9.5 ± 3.5 min . The areas under the receiver-operator characteristic curve from MRA images according to vessel- and patient-based analyses were 0.91 ( 95 % confidence interval [ CI ] : 0.87 to 0.95 ) and 0.87 ( 95 % CI : 0.81 to 0.93 ) , respectively . The sensitivity , specificity , positive and negative predictive values , and accuracy of MRA according to a patient-based analysis were 88 % ( 49 of 56 , 95 % CI : 75 % to 94 % ) , 72 % ( 51 of 71 , 95 % CI : 60 % to 82 % ) , 71 % ( 49 of 69 , 95 % CI : 59 % to 81 % ) , 88 % ( 51 of 58 , 95 % CI : 76 % to 95 % ) , and 79 % ( 100 of 127 , 95 % CI : 72 % to 86 % ) , respectively . CONCLUSIONS Non-contrast-enhanced whole-heart coronary MRA at 1.5-T can noninvasively detect significant CAD with high sensitivity and moderate specificity . A negative predictive value of 88 % indicates that whole-heart coronary MRA can rule out CAD OBJECTIVES The purpose of this study was to prospect ively evaluate the diagnostic performance of 3.0-T contrast-enhanced whole-heart coronary magnetic resonance angiography ( CMRA ) in patients with suspected coronary artery disease ( CAD ) . BACKGROUND A slow-infusion , contrast-enhanced whole-heart CMRA approach has recently been developed at 3.0-T. The accuracy of this technique has not yet been determined among patients with suspected CAD . METHODS The 3.0-T contrast-enhanced whole-heart CMRA was performed in 69 consecutive patients . An electrocardiography-triggered , navigator-gated , inversion-recovery prepared , segmented gradient-echo sequence was used to acquire isotropic whole-heart CMRA with slow infusion of 0.2 mmol/kg gadobenate dimeglumine . The diagnostic accuracy of whole-heart CMRA in detecting significant stenoses ( > or = 50 % ) was evaluated using X-ray angiography as the reference . RESULTS The CMRA examinations were successfully completed in 62 patients .  Acquisition time of whole-heart CMRA procedure was 9.0 + /- 1.9 min . The 3.0-T whole-heart CMRA correctly identified significant CAD in 32 patients and correctly ruled out CAD in 23 patients . The sensitivity , specificity , and accuracy of whole-heart CMRA for detecting significant stenoses were 91.6 % ( 87 of 95 ) , 83.1 % ( 570 of 686 ) , and 84.1 % ( 657 of 781 ) , respectively , on a per-segment basis . These values were 94.1 % ( 32 of 34 ) , 82.1 % ( 23 of 28 ) , and 88.7 % ( 55 of 62 ) , respectively , on a per-patient basis . CONCLUSIONS Contrast-enhanced whole-heart CMRA with 3.0-T allows for the accurate detection of coronary artery stenosis with high sensitivity and moderate specificity Noninvasive coronary angiography with multislice computed tomography ( CT ) scanners is feasible with high sensitivity and negative predictive value . The radiation exposure associated with this technique , however 
    Output:
    
Key Points• MRCA sensitivity and specificity for CAD are below those of CTA.• Contrast administration increased sensitivity to 95 % ( 90–97 % ) , comparable with that of CTA.• Whole-heart mode increased specificity to 78 % ( 72–84 % ) , comparable with that of CTA.• Specificity at 3 T was borderline-significantly higher ( p = 0.067 ) than at 1.5 T.• Whole-heart contrast-enhanced protocol s are the best approach for MRCA