OBJECTIVE To determine the relations between left atrial appendage function, spontaneous echo contrast, and thromboembolism in patients with different modes of permanent pacemakers. PATIENTS AND METHODS 88 patients with pacemaker implantation and 25 healthy controls in sinus rhythm had transoesophageal echocardiographic examination of the left atrial appendage. Left atrial size, appendage are...

The principles of contrast mechanisms and fast pulse sequences underlying neurological and neuroradiological application of MRI are introduced in this part of a two-part review. In particular, the relaxation time constants T(1), T(2), and T(2) (*) are introduced, along with pulse sequences harnessing their contrast, spin-echo, fast spin echo (FSE), inversion recovery (IR), gradient recalled ech...

PURPOSE To investigate dextran-coated superparamagnetic iron oxide particles (BMS 180549) as an MR contrast agent for assessing lymph nodes. METHODS Five different doses ranging from 0.3 to 1.7 mg Fe/kg were evaluated in five healthy human male subjects as part of a phase 1 clinical study. T1-, T2-, and proton density-weighted spin-echo images as well as multiplanar gradient-echo and spoiled ...

PURPOSE To determine optimal MR gradient-echo sequences for the visualization of calcium in neurologic MR. METHOD The dependence of signal intensity and image contrast on the imaging parameters repetition time, echo time, flip angle, and spoiling were measured for hydroxyapatite samples. Calculations of signal intensity were shown to correspond to these measures. RESULTS Optimum detectabili...

BACKGROUND AND PURPOSE Current T2-weighted imaging takes >3 minutes to perform, for which the ultrafast transition into driven equilibrium (TIDE) technique may be potentially helpful. This study qualitatively and quantitatively evaluates the imaging of transition into driven equilibrium of the balanced steady-state free precession (TIDE) compared with TSE and turbo gradient spin-echo on T2-weig...

BACKGROUND The number of competitive master athletes (MA, over 40 years) has been rising. Since the incidence of coronary artery disease (CAD) is increasing in this population, cardiovascular pre-participation screening, including a maximum exercise test, is recommended. In this context the addition of contrast to echo could be useful because wall thickening and motion are better markers of myo...

Purpose: Multi-echo Dixon-based methods have recently gained attention for use in contrast-enhanced MR angiography (CE-MRA) due to their ability to suppress the high signal from fat while avoiding subtraction errors due to motion between preand post-contrast images in subtraction CE-MRA. Additionally, multi-echo Dixon CE-MRA provides improved signal-to-noise ratio (SNR) and contrast-to-noise ra...

BACKGROUND AND PURPOSE MR imaging techniques have proved their efficacy in imaging the head and neck region. In this study, we compared T1-weighted, dual T2-weighted, and fat-suppressed MR imaging and unenhanced and contrast-enhanced 3D time-of-flight MR angiography sequences for detection of head and neck paragangliomas. METHODS Thirty-one patients with 70 paragangliomas were examined. Four ...