Current implementations of coronary artery magnetic resonance angiography (MRA) suffer from limited coverage of the coronary arterial system. Whole-heart coronary MRA was implemented based on a free-breathing steady-state free-precession (SSFP) technique with magnetization preparation. The technique was compared to a similar implementation of conventional, thin-slab coronary MRA in 12 normal volunteers. Three thin-slab volumes were prescribed: 1) a transverse slab, covering the left main (LM) artery and proximal segments of the left anterior ascending (LAD) and left circumflex (LCX) coronary arteries; 2) a double-oblique slab covering the right coronary artery (RCA); and 3) a double-oblique slab covering the proximal and distal segments of the LCX. The whole-heart data set was reformatted in identical orientations. Visible vessel length, vessel sharpness, and vessel diameter were determined and compared separately for each vessel. Whole-heart coronary MRA visualized LM/LAD (11.7 ؎ 3.4 cm) and LCX (6.9 ؎ 3.6 cm) over a significantly longer distance than the transverse volume (LM/ LAD, 6.1 ؎ 1.1 cm, P < 0.001; LCX, 4.2 ؎ 1.2 cm, P < 0.05). Improvements in visible vessel length for RCA and LCX in the whole-heart approach vs. their respective targeted volumes were not significant. It is concluded that the whole-heart coronary MRA technique improves visible vessel length and facilitates high-quality coronary MRA of the complete coronary artery tree in a single measurement.Magn The cornerstone of a definitive diagnosis of coronary artery disease, and its treatment, has for several decades been selective x-ray angiography. However, about 10 -15% of coronary angiograms disclose normal or near normal coronary artery morphology. Moreover, in many patients with a strong risk for coronary artery disease or known noncoronary-artery obstructive disease, coronary angiography is employed to exclude severe coronary artery disease prior to non-coronary vascular surgery. Selective angiography is also used in circumstances where the likelihood of destructive disease is low to moderate but certitude is essential, such as in preoperative evaluations of older patients undergoing non-coronary cardiac surgery, and in patients with dilated cardiomyopathy. Consequently, coronary MRA was developed as an alternative to selective angiography in some of these clinical scenarios.MR methods to image the coronary arteries and suspected lesions have been under development for more than a decade. In recent years, methodological improvements involving both breath-hold and free-breathing methods with different contrast mechanisms have been made (1). A recent multicenter study (2), which included 109 patients, demonstrated a relatively good ability to detect or exclude significant stenoses (Ͼ50%) of the left main (LM) artery, as well as the proximal segments of the left anterior descending (LAD), the left circumflex (LCX), and the right coronary (RCA) arteries. That study employed a magnetization-prepared, free-breathing spoiled turbo-field echo (TFE...

Background and Purpose-Evolution of intracranial aneurysmal disease is known to be related to hemodynamic forces acting on the vessel wall. Low wall shear stress (WSS) has been reported to have a negative effect on endothelial cells normal physiology and may be an important contributor to local remodeling of the arterial wall and to aneurysm growth and rupture. Methods-Seven patient-specific models of intracranial aneurysms were constructed using MR angiography data acquired at two different time points (mean 16.4Ϯ7.4 months between the two time points). Numeric simulations of the flow in the baseline geometries were performed to compute WSS distributions. The lumenal geometries constructed from the two time points were manually coregistered, and the radial displacement of the wall was calculated on a pixel-by-pixel basis. This displacement, corresponding to the local growth of the aneurysm, was compared to the time-averaged wall shear stress (WSS TA ) through the cardiac cycle at that location. For statistical analysis, radial displacement was considered to be significant if it was larger than half of the MR pixel resolution (0.3 mm). Results-Mean

Purpose: To determine the diagnostic performance of liver apparent diffusion coefficient (ADC) measured with conventional diffusion-weighted imaging (CDI) and diffusion tensor imaging (DTI) for the diagnosis of liver fibrosis and inflammation. Materials and Methods:Breathhold single-shot echo-planar imaging CDI and DTI with b-values of 0 and 500 second/mm 2 was performed in 31 patients with chronic liver disease and 13 normal volunteers. Liver biopsy was performed in all patients with liver disease with a median delay of two days from MRI. Fibrosis and inflammation were scored on a 5-point scale (0 -4). Liver ADCs obtained with CDI and DTI were compared between patients stratified by fibrosis stage and inflammation grade. Receiver operating characteristic (ROC) curve analyses were conducted to evaluate the utility of the ADC measures for prediction of fibrosis and inflammation. Results:Patients with liver fibrosis and inflammation had significantly lower liver ADC than subjects without fibrosis or inflammation with CDI and DTI. For prediction of fibrosis stage Ն 1 and stage Ն 2, area under the ROC curve (AUC) of 0.848 and 0.783, sensitivity of 88.5% to 73.7%, and specificity of 73.3% to 72.7% were obtained, for ADC Յ1.40 ϫ 10 -3 mm 2 /second and Յ1.30 ϫ 10 -3 mm 2 /second (using CDI), respectively. For prediction of inflammation grade Ն 1, AUC of 0.825, sensitivity of 75.0%, and specificity of 78.6% were obtained using ADC Յ 1.30 ϫ 10 -3 mm 2 /second (using CDI). CDI performed better than DTI for diagnosis of fibrosis and inflammation. Conclusion:Liver ADC can be used to predict liver fibrosis and inflammation with acceptable sensitivity and specificity.