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.

High-resolution CMR MPR at 3.0-T can be used to detect flow-limiting CAD as defined by FFR, using both visual and quantitative analyses.

Native T1 exhibited comparable ability as ECV measurement in the detection and quantification of histological collagen volume fraction, with high reproducibility, and therefore diffuse myocardial fibrosis in DCM may be reliably assessed by native T1 mapping without the administration of gadolinium contrast agent. In addition, cardiac magnetic resonance-derived ECV showed excellent agreement with histological extracellular space.

No abstract

Background: The dual-bolus protocol enables accurate quantification of myocardial blood flow (MBF) by first-pass perfusion cardiovascular magnetic resonance (CMR). However, despite the advantages and increasing demand for the dual-bolus method for accurate quantification of MBF, thus far, it has not been widely used in the field of quantitative perfusion CMR. The main reasons for this are that the setup for the dual-bolus method is complex and requires a state-of-the-art injector and there is also a lack of post processing software. As a solution to one of these problems, we have devised a universal dual-bolus injection scheme for use in a clinical setting. The purpose of this study is to show the setup and feasibility of the universal dual-bolus injection scheme.

The objectives of this study were to develop a method for quantifying myocardial K 1 and blood flow (MBF) with minimal operator interaction by using a Patlak plot method and to compare the MBF obtained by perfusion MRI with that from coronary sinus blood flow in the resting state. A method that can correct for the nonlinearity of the blood time-signal intensity curve on perfusion MR images was developed. Myocardial perfusion MR images were acquired with a saturation-recovery balanced turbo field-echo sequence in 10 patients. Coronary sinus blood flow was determined by phasecontrast cine MRI, and the average MBF was calculated as coronary sinus blood flow divided by left ventricular (LV) mass obtained by cine MRI. Patlak plot analysis was performed using the saturation-corrected blood time-signal intensity curve as an input function and the regional myocardial time-signal intensity curve as an output function. Dynamic MRI following the bolus injection of gadolinium contrast medium permits the assessment of first-pass myocardial enhancement, which can yield information concerning regional myocardial blood flow (MBF). First-pass myocardial perfusion MR images obtained in patients have been evaluated by visual assessment (1-3) and by semiquantitative approaches such as upslope analysis of the myocardial time-intensity curve (4 -7). The use of fullyquantitative analysis of myocardial first-pass contrast-enhanced MRI allows the absolute quantification of MBF in units of ml/min/100 g and may permit more accurate and objective assessment of altered myocardial perfusion in patients with heart disease. Quantitative analysis of firstpass contrast-enhanced MRI has been performed by either a Fermi function deconvolution method (8 -14) or compartment model analysis (15)(16)(17)(18)(19)(20).Quantitative assessment of myocardial perfusion MRI with a compartmental analysis approach has been investigated by several investigators since the early 1990s. Diesbourg et al. (16) used a modified Kety equation to determine the myocardial tissue distribution and clearance of gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA) from contrast-enhanced MR images (15,16). Larsson et al. (17,18) quantified MBF from contrast-enhanced MR images of the human heart using two-compartment model analysis. The unidirectional influx constant (Ki) of Gd-DTPA across the capillary membrane in human myocardium was quantified by measuring the longitudinal relaxation rate (R 1 ) of the myocardium with contrast-enhanced MRI and obtaining the input function with arterial blood sampling. The Ki value, which is related to the extraction fraction (E) and MBF by the equation Ki ϭ E ⅐ MBF, was 54 Ϯ 10 ml/min/100 g in their study. Vallée et al. (19) modified Larsson et al.'s (17,18) two-compartment model by defining the myocardial capillaries and the extracellular space as a single compartment. A region-ofinterest (ROI) was placed in the left ventricular (LV) chamber to measure the arterial input function from first-pass contrast-enhanced MR images. It should...

There is good correlation between MPR(CMR) and MPR(PET.) For the detection of significant CAD, MPR(PET) and MPR(CMR) seem comparable and very accurate. However, absolute perfusion values from PET and CMR are only weakly correlated; therefore, although quantitative CMR is clinically useful, further refinements are still required.

Entry closure with endovascular stent-graft placement may be a safe and effective method for the treatment of patients with aortic dissection. It could be an alternative to conventional surgical intervention in selected patients with chronic dissection. However, strict patient selection and close follow-up seem mandatory in patients with acute dissection receiving Z stent-based stent-grafts. Stent-graft repair should be delayed for acute type B dissection without complications.