***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 —With MRI , an index of myocardial perfusion reserve ( MPRI ) can be determined . We assessed the value of this technique for the noninvasive detection of coronary artery disease ( CAD ) in patients with suspected CAD . Methods and Results —Eighty-four patients referred for a primary diagnostic coronary angiography were examined with a 1.5 T MRI tomograph ( Philips-ACS ) . For each heartbeat , 5 slices were acquired during the first pass of 0.025 mmol gadolinium-diethylenetriamine pentaacetic acid/kg body weight before and during adenosine vasodilation by using a turbo-gradient echo/echo-planar imaging-hybrid sequence . MPRI was determined from the alteration of the upslope of the myocardial signal intensity curves for 6 equiangular segments per slice . Receiver operating characteristics were performed for different criteria to differentiate ischemic and nonischemic segments . Prevalence of CAD was 51 % . Best results were achieved when only the 3 inner slices were assessed and a threshold value of 1.1 was used for the second smallest value as a marker for significant CAD . This approach yielded a sensitivity of 88 % , specificity of 90 % , and accuracy of 89 % . Conclusion —The determination of MPRI with MRI yields a high diagnostic accuracy in patients with suspected CAD Summary Background Real world cardiology is faced with a low diagnostic yield of coronary angiography ( CXA ) in patients presenting with ACC/AHA class II CXA indication . Our aim was to analyze the clinical implication of a Cardiac MR ( CMR ) protocol including adenosine stress perfusion in this patient population . We examined whether CMR could enhance appropriate CXA indication and thus reduce the rate of pure diagnostic CXA . In addition , we compared the relative impact of CMR exam components ( perfusion , function and viability assessment ) in achieving this target . Methods 176 patients were referred for CXA with class II indication . 171 underwent complete additional CMR exam in a 1.5-T whole body CMR-scanner for myocardial function , ischemia and viability prior to CXA . The routine protocol for assessment of CAD consisted of functional imaging ( long and short axes ) , adenosine stress- and rest-perfusion in short axis orientation and “ late enhancement ” imaging in long and short axes . Images were analyzed by two independent and blinded investigators . Interobserver differences were resolved by a third reader . Results There was a high association between CMR results and subsequent invasive findings ( chi square for CMR perfusion deficit and stenosis > 70 % in CXA : 113.7 , p<0.0001 ) . 109 ( 63.7 % ) of our patients had relevant perfusion deficits as seen by CMR and matching coronary artery stenosis > 70 % . Four ( 2.3 % ) patients had false negative CMR findings . In 58 patients ( 33.9 % ) no relevant coronary artery stenosis could be observed , correctly predicted by CMR in 48 cases ; in 10 ( 5.8 % ) patients CMR provided false positive results . Sensitivity of CMR to detect relevant CAD ( > 70 % luminal narrowing ) was 0.96 , specificity 0.83 , positive predictive value 0.92 and negative predictive value 0.92 . Of the CMR components , perfusion deficit was the strongest independent predictor ( odds ratio 132.3 , p < 0.0001 ) . Conclusion In a great number of patients being referred to cath lab with ACC/AHA class II indication for CXA , CMR provides a high accuracy for decision making regarding appropriateness of the invasive exam . CMR prior to CXA could substantially reduce pure diagnostic coronary angiographies in patients with intermediate probability for CAD , in our patient-cohort from approximately 34 % to 6 % . Further studies are warranted to identify rare false negative CMR results BACKGROUND Qualitative interpretation of myocardial contrast echocardiography ( MCE ) improves the accuracy of wall-motion analysis for assessment of coronary artery disease ( CAD ) . We examined the feasibility and accuracy of quantitative MCE for diagnosis of CAD . METHODS Dipyridamole/exercise stress MCE ( destruction-replenishment protocol with real-time imaging ) was performed in 90 patients undergoing quantitative coronary angiography , 48 of whom had significant ( > 50 % ) stenoses .  MCE was repeated with exercise alone in 18 patients .  Myocardial blood flow ( A*beta ) was obtained from blood volume ( A ) and time to refill ( beta ) . RESULTS Quantification of flow reserve was feasible in 88 % . The mean A*beta reserve in the anterior wall was significantly impaired for patients with left anterior descending coronary artery disease ( n = 28 ) compared with those with no disease ( 1.6 + /- 1.2 vs 4.0 + /- 2.5 , P < or = .001 ) . This reflected impaired beta reserve , with no difference in the A reserve . Applying a receiver operating characteristic curve derived cutoff of 2.0 for A*beta reserve , quantitative MCE was 76 % sensitive and 71 % specific for the diagnosis of significant left anterior descending coronary artery stenosis . Posterior circulation results were similar , with 78 % sensitivity and 59 % specificity for detection of posterior CAD . Overall , quantitative MCE was similarly sensitive to qualitative approach for diagnosis of CAD ( 88 % vs 93 % ) , but with lower specificity ( 52 % vs 65 % , P = .07 ) . In 18 patients restudied with pure exercise stress , the mean myocardial blood flow reserve was less than after combined stress ( 2.1 + /- 1.6 vs 3.7 + /- 1.9 , P = .01 ) . CONCLUSION Quantitative MCE is feasible for the diagnosis of CAD with dipyridamole/exercise stress . Dipyridamole prolongs postexercise hyperemia , augmenting the degree of hyperemia at the time of imaging To investigate prospect ively , in patients with suspicion of coronary artery disease ( CAD ) , the added value of coronary calcium scoring ( CS ) as adjunct to cardiac magnetic resonance ( CMR ) for the diagnosis of morphological coronary stenosis in comparison to catheter angiography ( CA ) . Sixty consecutive patients ( 8 women ; 64 ± 10 years ) referred to CA underwent CMR ( 1.5 T ) including perfusion and late gadolinium-enhancement imaging as well as CS with computed tomography .  Diagnostic performance was evaluated for CMR and CS separately , and for both methods combined , with CA as reference st and ard . Best CS threshold combined with a specificity > 90 % to predict significant stenosis in patients without abnormalities on CMR was determined from receiver operator characteristics ( ROC ) analysis . Abnormal CMR results were considered to indicate significant stenosis regardless of CS ; CS above threshold reclassified patients to have CAD regardless of CMR . CA identified 104/960 ( 11 % ) coronary segments with coronary artery stenosis > 50 % in 36/60 ( 60 % ) patients . ROC revealed an area-under-the-curve of 0.83 ( 95%CI : 0.68 - 0.99 ) with the best CS threshold of 495 Agatston score ( sensitivity 50 % ) . CMR depicted 128/960 ( 13 % ) myocardial segments with abnormalities in 31/60 ( 52 % ) patients . Sensitivity , specificity , negative ( NPV ) and positive predictive value ( PPV ) of CMR were 78 , 88 , 72 and 90 % . When adding CS to CMR  , sensitivity and NPV increased to 89 and 83 % , while specificity and PPV slightly decreased to 83 and 89 % . Accuracy of the combined approach ( 87 % ) was significantly ( P < 0.05 ) higher than that of CMR ( 82 % ) alone . Adding CS to CMR  improves the accuracy for the detection of morphological CAD UNLABELLED The purpose of this study was to prospect ively evaluate the diagnostic accuracy of a cardiovascular magnetic resonance ( MR ) k-space and time ( k-t ) broad-use linear acquisition speed-up technique ( BLAST ) accelerated perfusion sequence for depicting clinical ly relevant coronary artery disease ( CAD ) , with use of coronary angiography as the reference st and ard . The local ethics committee approved this study , and informed consent was obtained from 40 patients ( 28 men , 12 women ; mean age , 61 years + /- 8 [ st and ard deviation ] ) scheduled for coronary catheterization . A balanced steady-state free precession pulse sequence ( 2.6 x 2.6 x 10 mm ) with a net k-t acceleration factor of 3.8 ( repetition time msec/echo time msec , 3.2/1.6 ; flip angle , 50 degrees ) was applied . Visual analysis of perfusion images and quantitative analysis of signal-time curves obtained in the myocardium were performed by using segmental myocardial upslope , peak enhancement , and their respective ratios . Visual analysis revealed sensitivity , specificity , and diagnostic accuracy of 86 % , 78 % , and 83 % , respectively , in the detection of coronary stenoses with at least 50 % luminal narrowing . Significant ( P < .05 ) changes between ischemic and remote segments could be shown for all perfusion indexes applied . Use of myocardial perfusion imaging with k-t BLAST for accelerated data acquisition is feasible in the identification of patients with substantial CAD ( coronary stenosis > or= 50 % ) . SUPPLEMENTAL MATERIAL http://radiology.rsnajnls.org/cgi/content/full/245/3/863/DC1 The coronary artery calcium ( CAC ) score is a readily and widely available tool for the noninvasive diagnosis of atherosclerotic coronary artery disease ( CAD ) . The aim of this study was to investigate the added value of the CAC score as an adjunct to gated SPECT for the assessment of CAD in an intermediate-risk population . Methods : Seventy-seven prospect ively recruited patients with intermediate risk ( as determined by the Framingham Heart Study 10-y CAD risk score ) and referred for coronary angiography because of suspected CAD underwent stress 99mTc-tetrofosmin SPECT myocardial perfusion imaging ( MPI ) and CT CAC scoring within 2 wk before coronary angiography . The sensitivity and specificity of SPECT alone and of the combination of the 2 methods ( SPECT plus CAC score ) in demonstrating significant CAD ( ≥50 % stenosis on coronary angiography ) were compared . Results : Forty-two ( 55 % ) of the 77 patients had CAD on coronary angiography , and 35 ( 45 % ) had abnormal SPECT results . The CAC score was significantly higher in subjects with perfusion abnormalities than in those who had normal SPECT results ( 889 ± 836 [ mean ± SD ] vs. 286 ± 335 ; P < 0.0001 ) . Similarly , with rising CAC scores , a larger percentage of patients had CAD . Receiver-operating-characteristic analysis showed that a CAC score of greater than or equal to 709 was the optimal cutoff for detecting CAD missed by SPECT . SPECT alone had a sensitivity and a specificity for the detection of significant CAD of 76 % and 91 % , respectively . Combining SPECT with the CAC score ( at a cutoff of 709 ) improved the sensitivity  of SPECT ( from 76 % to 86 % ) for the detection of CAD , in association with a nonsignificant decrease in specificity ( from 91 % to 86 % ) . Conclusion : The CAC score may offer incremental diagnostic information over SPECT data for identifying patients with significant CAD and negative MPI results Myocardial flow reserve ( MFR ) is not routinely assessed in myocardial perfusion imaging ( MPI ) studies but has been hypothesized to affect test accuracy when assessing disease severity by coronary vessel lumenography . Magnetic resonance imaging ( MRI ) is an emerging diagnostic technique that can both perform MPI and assess MFR . We studied women ( n = 184 ) enrolled in the Women 's Ischemia Syndrome Evaluation ( WISE ) study with symptoms suggesting ischemic heart disease . Tests performed were coronary angiography and MPI by both MR and gated radionuclide single photon emission computed tomography ( gated-SPECT ) . The MFR index was calculated using the MR data acquired at baseline and under vasodilation ( dipyridamole ) conditions . The study was structured with a pilot and an implementation phase . During the pilot phase ( n = 46 ) data were unmasked and an MFR threshold was defined to divide patients into those with an adequate ( AMFRI ) or inadequate ( IMFRI ) MFR index . During the implementation phase , the MFR index threshold was prospect ively applied to patients ( n = 138 ) . In the implementation phase , MPI ischemia detection accuracy compared to severe ( > or = 70 % ) coronary artery diameter narrowing by angiography was higher in the AMFRI vs. the IMFRI group for MRI ( 86 % vs. 70 % , p < 0.05 ) and gated-SPECT ( 89 % vs. 67 % , p < 0.01 ) . The IMFRI group ( n = 55 , 30 % of study population ) had a higher resting rate-pressure product compared with the AMFRI group ( 10,599 + /- 2871 vs. 
    Output:
    
Conclusion Our results suggest that MRI is superior for the diagnosis of obstructive CAD compared with ECHO and SPECT .
ECHO and SPECT demonstrated similar diagnostic performance .
Key Points• MRI can assess myocardial perfusion.• MR perfusion diagnoses coronary artery disease better than echocardiography or SPECT.• Echocardiography and SPECT have similar diagnostic performance.•  MRI can save coronary artery disease patients from more invasive tests.• MRI and SPECT show evidence of publication bias , implying possible overestimation