Interactive drawing of the left ventricular borders from cine magnetic resonance images

Right ventricular volumes and ejection fraction with fast cine MR imaging in breath-hold technique: applicability, normal values from 52 volunteers, and evaluation of 325 adult cardiac patients

Our goal was to establish right ventricular (RV) volume and ejection fraction (EF) values in normal volunteers with fast magnetic resonance (MR) imaging using a breath-hold technique, to assess the frequency and severity of RVEF abnormality in cardiac patients and to compare RV with left ventricular (LV) data. We performed simultaneously derived RV and LV fast cine measurements in 52 normals and 325 patients with coronary artery disease (CAD), acquired valvular disease (VD), cardiomyopathy (CM), or congenital heart disease (CHD). RVEF was reduced in 31% (102) of all patients, in 50% dilated CM, 39% CHD, 34% CAD, and 22% acquired VD patients. Solitary abnormally low RVEF was found in only 15/325 (5%) of all patients, whereas combined with LVEF deterioration in 87/172 (51%) patients. RVEF reduction was mild in 64%, moderate in 25%, and severe in 11%. Although RVEF correlated significantly (r = 0.55, P < 0.001) with LVEF, the predictive value of LVEF for RVEF was low. We conclude that RV volumes can be routinely assessed with fast MRI and should be performed in addition to LV evaluation in CHD, in right-sided VD, and in all patients with an abnormal LVEF.J. Magn. Reson. Imaging 1999; 10:908-918.

Experimental validation of an automated edge-detection method for a simultaneous determination of the endocardial and epicardial borders in short-axis cardiac MR images: application in normal volunteers

The goal of this study was to put together several techniques of image segmentation to provide a reliable assessment of the left ventricular mass with short-axis cardiac MR images. No initial manual input was required for this process based on region growing, gradient detection, and adaptive thresholding. A comparison between actual mass and automatic assessment was implemented with 9 minipigs that underwent spin-echo MR imaging. Fifteen normal volunteers were studied with a fast-gradient-echo sequence. The automatic segmentation was then controlled by three trained observers. Actual mass and automatic segmentation were strongly correlated (r = .97 with P < .01). For normal volunteers, the standard error of estimation of the automatic assessment (12 g) compared well with the average myocardial mass (120 +/- 30 g) and the interobserver reproducibility of the manual assessment (9 g). These results allow the application of this method to the quantification of the left ventricular function and mass in clinical practice.

Comparison between qualitative and quantitative wall motion analyses using dipyridamole stress breath-hold cine magnetic resonance imaging in patients with severe coronary artery stenosis

Breath-hold cine magnetic resonance imaging (MRI) at rest and during dipyridamole infusion was used to study wall motion abnormalities in patients with severe coronary artery stenosis proven by coronary angiography. Sixteen patients without myocardial infarction but at least one major coronary artery with > or = 70% diameter narrowing were included. Qualitative "visual" assessment of wall motion, as well as quantitative measurement "wall thickening changes (%)" were compared using receiver operating characteristic curve analysis. 201Tl-single-photon emission computed tomography (SPECT) was also studied for comparison. Using qualitative analysis, coronary artery disease detection rate was comparable when assessing wall motion abnormalities with dipyridamole-MRI (79%) and with dipyridamole-induced perfusion defects with 201-thallium-SPECT (75%). Furthermore, sensitivity and specificity for identification of all diseased coronary territories were comparable for both imaging modalities (sensitivity of dipyridamole-MRI and 201thallium-SPECT, 80% vs. 69%; specificity, 75% vs. 80%). The quantitative method has a substantially higher sensitivity than the qualitative method in identifying all diseased territories (Az = 0.81, p < 0.01 vs. Az = 0.55 and 0.59). In addition, we demonstrated that the quantitative method had higher performance than the qualitative one in identifying the diseased vessels territories related to 1-vessel, 2-vessel, and each of individual coronary artery stenoses.