***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 
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    ***EXAMPLES*** 
    Input: Background —We prospect ively evaluated the incremental prognostic value of transient ischemic dilation ( TID ) in patients with type 2 diabetes mellitus during long-term follow-up and estimated cardiac death and nonfatal myocardial infa rct ion ( MI ) using traditional approaches of prognostication to more recent methods . Methods and Results —A total of 672 consecutive diabetic patients with available rest and stress gated myocardial perfusion single-photon emission computed tomographic data were enrolled . Stepwise Cox regression analysis was used to estimate cardiac death or nonfatal MI . Risk reclassification was calculated , and an exploratory analysis was performed to evaluate the effect of coronary revascularization on event-free survival . Adding TID to a multivariable model , including age , history of MI , stress type , poststress left ventricular ejection fraction , and stress-induced myocardial ischemia , improved discrimination of cardiac death or nonfatal MI ( C statistic , 0.74–0.82 ; P=0.01 ; adjusted hazard ratio , 3.6 ; P<0.0001 ) and led to a net reclassification improvement of 0.39 ( 95 % confidence interval , 0.14–0.64 ) . Revascularization had a significant effect on event-free survival ( adjusted hazard ratio , 0.25 ; P<0.001 ) , with significant interactions between revascularization and poststress left ventricular ejection fraction , revascularization and stress-induced myocardial ischemia , and revascularization and TID ( all P<0.01 ) Conclusions —TID provides independent and incremental prognostic information for the prediction of cardiac death or nonfatal MI in patients with diabetes mellitus . The addition of TID to a prediction model based on cardiovascular risk factors , left ventricular ejection fraction , and ischemia significantly improves risk discrimination and reclassification for incident cardiac events . The effect of revascularization seems to be influenced by left ventricular systolic function , stress-induced myocardial ischemia , and TID UNLABELLED Transient ischemic dilation of the left ventricle found on SPECT myocardial perfusion imaging ( MPI ) is an accepted marker of severe and extensive coronary artery disease ( CAD ) and poor prognosis . The influence of other clinical variables on the incidence of transient ischemic dilation is less certain . The aim of this study was to investigate clinical factors that may influence the incidence of transient ischemic dilation . In particular , we looked at factors that may independently affect subendocardial perfusion , such as left ventricular hypertrophy ( LVH ) and diabetes . METHODS MPI studies of 103 consecutive patients who had undergone recent coronary angiography ( < or = 6 mo ) and transthoracic echocardiography within a year of stress electrocardiography-gated MPI  were retrospectively analyzed . Transient ischemic dilation was assessed quantitatively using a software program . A ratio cutoff of > or = 1.22 was considered to represent transient ischemic dilation . Summed stress score and summed difference score ( ischemia score ) were determined using the st and ard 17-segment 5-point scoring system to quantify myocardial ischemia . LVH was defined as a left ventricular wall thickness of > 11 mm on M-mode echocardiography . Severe CAD was defined as severe stenosis ( > or = 90 % ) of either the left anterior descending artery or both the right coronary and lateral circumflex arteries . RESULTS Nineteen ( 18 % ) of the 103 patients had transient ischemic dilation , 19 ( 18 % ) had LVH , and 23 ( 22 % ) were diabetic . A high percentage had severe CAD ( 46/103 [ 45 % ] ) , whereas 57 of 103 ( 55 % ) had less severe CAD ( 30/103 [ 29 % ] ) or nonsignificant CAD ( 26/103 [ 25 % ] ) . Severe CAD ( P < 0.001 ) , diabetes ( P < 0.0001 ) , LVH ( P < 0.003 ) , and the ischemia score ( P < 0.023 ) were independent predictors of transient ischemic dilation by multivariate logistic regression . In patients with severe CAD , the effect of LVH on the incidence of transient ischemic dilation was additive , increasing the incidence from 21 % ( 8/38 ) without LVH to 75 % ( 6/8 ) with LVH ( P < 0.006 ) . Likewise , with severe CAD , the incidence of transient ischemic dilation rose from 21 % ( 7/33 ) in patients without diabetes to 54 % ( 7/13 ) in those with diabetes ( P < 0.04 ) . CONCLUSION The presence of transient ischemic dilation on myocardial perfusion SPECT is associated with the presence of severe CAD , but this association is modified by the presence of LVH and diabetes UNLABELLED The aim of our study was to derive and to vali date the normal threshold for an automatically measured left ventricular transient ischemic dilation ( TID ) ratio in patients referred for adenosine stress myocardial perfusion SPECT ( MPS )  and to assess the value of integrating TID in detecting severe and extensive coronary artery disease ( CAD ) . METHODS Normal limits for the TID ratio were derived using  dual-isotope MPS data from 38 patients with a low ( < 5 % ) likelihood of CAD . Criteria for abnormality were calculated on the basis of data from 179 consecutive patients who had undergone coronary angiography less than 3 mo after index adenosine MPS : 41 patients ( 23 % ) had severe and extensive CAD ( > or = 90 % stenosis ) in the proximal left anterior descending artery or in 2 or more coronary arteries , 64 ( 36 % ) had no significant CAD ( < 70 % stenosis ) , and 74 ( 41 % ) had mild or moderate CAD . The criteria were then prospect ively vali date d in a cohort of 177 patients , of whom 41 patients ( 23 % ) had severe and extensive CAD , 55 ( 31 % ) had no significant CAD , and 81 ( 46 % ) had mild or moderate CAD . RESULTS By analysis of receiver-operating-characteristic curves , the best threshold for adenosine TID ratio abnormality was the mean adenosine TID ratio in the low-CAD-likelihood patients + 2 SDs ( TID ratio > 1.36 ) . Abnormal TID ratio using this threshold demonstrated high sensitivity and specificity for severe and extensive CAD ( 71 % and 86 % , respectively ) , and similar sensitivity and specificity were observed in the prospect i ve validation group ( 73 % and 88 % , respectively ) . In the combined pilot and validation groups , the absence of both abnormal TID ratio and abnormal perfusion was highly specific for the absence of severe and extensive CAD ; only one ( 1.3 % ) of 79 patients with severe and extensive CAD had neither of these abnormal findings on adenosine MPS . In patients with both abnormal TID ratio and abnormal perfusion , 55 of 84 ( 65 % ) had severe and extensive CAD . When patients had one but not both of these findings , 26 of 193 ( 13 % ) had severe and extensive CAD . CONCLUSION The automatically measured TID ratio is a useful clinical marker that is sensitive and highly specific for identification of severe and extensive CAD in patients undergoing adenosine MPS . Integration of abnormal TID ratio into the dual-isotope MPS image interpretation algorithm improves the identification of severe and extensive CAD in adenosine MPS Background . Diabetes and left ventricular hypertrophy ( LVH ) can cause coronary flow reserve abnormalities in the absence of coronary artery disease ( CAD ) . We sought to evaluate the impact of LVH and diabetes on the relationship between ischemia , severe CAD , and transient ischemic dilation ( TID ) on adenosine myocardial perfusion imaging ( MPI ) . Methods and Results . We prospect ively recruited 157 patients referred for routine single-day adenosine technetium 99 m MPI .  LVH was assessed by use of  transthoracic echocardiography .  A ratio of 1.19 or greater on MPI defined TID in men and 1.31 or greater in women . Summed difference scores were determined by use of a 17-segment 5-point scoring system . TID was present in 22 of 157 patients ( 14 % ) , diabetes in 54 of 157 ( 34 % ) , and LVH in 42 of 157 ( 27 % ) . By multivariate logistic regression , LVH , ischemia ( summed difference score > 2 ) , and diabetes were independently predictive of TID . The incidence of TID was stratified by the presence or absence of diabetes and /or LVH in those with ischemia on MPI ( 8/8 [ 100 % ] vs 0/11 [ 0 % ] , P<.002 ) or severe CAD on angiography ( 5/7 [ 71 % ] vs 0/8 [ 0 % ] , P<.01 ) . All those with TID ( 22/22 [ 100 % ] ) had either diabetes or LVH ( or both ) . Conclusion . Although this study confirms the association between TID and both ischemia and severe CAD , all patients with TID had diabetes , LVH , or frequently , both , suggesting that the pathophysiology of these disease processes may play an integral role in the manifestation of TID on adenosine MPI Several studies have shown the accuracy of gated single photon emission computed tomography ( SPECT ) using thallium-201 and technetium tracers in the assessment of myocardial perfusion and function . Gated SPECT has been successfully utilized to detect post-stress left ventricular ejection fraction ( LVEF ) reduction result ing from post-ischemic stunning in patients with coronary obstruction . The aim of this study was to evaluate whether the post-stress LVEF impairment could be related to the post-stress end-systolic ventricular dilation result ing from post-ischemic endocardial stunning . Two hundred and eighty-two consecutive patients were studied by conventional diagnostic 2 day stress/rest gated SPECT following injection of 925 MBq of 99mTc-tetrofosmin using a dual-headed SPECT camera . One hundred and forty-seven of these patients ( 52 % ) showed reversible perfusion defects , 69 ( 24 % ) permanent defects and the remaining 66 ( 24 % ) had normal perfusion . One hundred and thirty-eight of these patients had a history of myocardial infa rct ion ( MI ) and 19 % underwent coronary angiography  without an intervening cardiac event . Perfusion was analysed on ungated images using 20 segments scored on a five-point scale ( 0 , normal ; 4 , no uptake ) , while wall thickening ( WT ) was assessed visually on stress/rest end-systolic images using a four-point score ( 0 , normal ; 3 , absence of WT ) . LVEF and volumes were calculated using an automatic algorithm . The post-stress and rest ratios were determined for both end-diastolic ( EDV ) and end-systolic ( ESV ) volume . Normal values for all these parameters were obtained using data from 149 patients with a low likelihood ( < 5 % ) of coronary artery disease ( CAD ) . In 50 of the 147 ( 34 % ) of patients with reversible perfusion defects , post-stress LVEF was > 5 % lower than rest values ( stunned group ) , while the remaining 97 patients did not show a significant LVEF change ( group 2A ) . The percentage of patients who developed exercise-induced angina , the percentage of patients who underwent coronary angiography and the segmental summed perfusion and WT scores were significantly higher in the stunned group compared with group 2A . Only ESV increased significantly post-stress , and this increase occurred only in stunned patients . Both EDV and ESV ratios were significantly higher in the stunned group compared with normal controls ( P = 0.008 and P<0.000001 , respectively ) and with the subgroup 2A ( P = 0.011 and P<10−12 , respectively ) . The ESV stress/rest ratio correlated significantly with the summed WT difference score by univariate analysis in stunned patients . It can be concluded that the post-stress ESV dilation , obtained by stress/rest gated SPECT , seems to be due to endocardial post-ischemic stunning . The stunned patients showed more severe clinical , angiographic , perfusion and function parameters OBJECTIVES This study sought to assess whether a transient ischemic dilation ratio , determined from automatically derived stress and rest left ventricular volumes during stress technetium-99 m ( Tc-99 m ) sestamibi/rest thallium-201 dual-isotope myocardial perfusion single-photon emission computed tomography ( SPECT ) , is useful for the identification of patients with severe and extensive coronary artery disease . BACKGROUND Transient ischemic dilation of the left ventricle on stress/redistribution thallium-201 scintigraphy has been shown to be a clinical ly useful marker of severe and extensive coronary artery disease . However , in practice , its assessment 
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Analysis of outcome data demonstrated increased cardiac event rates in patients with TID and an abnormal MPI .
In otherwise normal perfusion , TID is an indicator of poor prognosis in patients with diabetes and /or a history of coronary disease .
Conclusions Among patients undergoing MPI , the presence of TID is specific for the detection of extensive or severe coronary artery disease .
El análisis de los datos de result ado demostró un aumento de las tasas de eventos cardíacos en pacientes con TID y un EPM anormal .
En la perfusión normal , la TID es un indicador de mal pronóstico en pacientes con diabetes y/o antecedentes de enfermedad coronaria .
Conclusion esEn pacientes que son llevados a un EPM , la presencia de TID es especifico para la detección de enfermedad arterial coronaria extensa o severa .
Une augmentation du nombre d’événements cardiaques est présente chez les patients démontrant une DIT avec étude anormale de perfusion myocardique .
Lorsque la perfusion myocardique est normale , une DIT est également un facteur de mauvais pronostic chez les patients atteints de diabète et/ou d’un antécédent de maladie coronarienne .
Conclusions La présence d’une DIT obtenue par scintigraphie myocardique est spécifique pour la détection de la maladie coronaire étendue ou sévère