Comparison of the reproducibility of quantitative cardiac left ventricular assessments in healthy volunteers using different MRI scanners: a multicenter simulation.

PURPOSE: To derive reproducibility assessments of ejection fraction (EF) and left ventricular mass (LVM) from short-axis cardiac MR images acquired at single and multiple time-points on different 1.5T scanner models. MATERIALS AND METHODS: Images of 15 healthy volunteers were acquired twice using a Magnetom Avanto scanner (Siemens, Erlangen, Germany) and once using a Signa Excite scanner (General Electric, Milwaukee, WI, USA) over four months, and analyzed using ARGUS and MASS Analysis+ software, respectively. Two physicists independently segmented the myocardial borders in order to derive intra- and interobserver assessments of EF and LVM for single and multiple time-points on the same and different scanners. RESULTS: For EF, the coefficient of repeatability (CoR) increased as different observers, multiple time-points, and different scanners were introduced. The CoR ranged from 2.8% (intraobserver measurements, single time-point, same scanner) to 10.0% (interobserver measurements, different time-points, different scanners). For LVM, intraobserver CoR parameters were consistently smaller than interobserver values. The CoR ranged from 7.8 g (intraobserver measurements, single time-point, same scanner) to 39.5 g (interobserver measurements, different time-points, different scanners). CONCLUSION: Reproducible EF data can be obtained at single or multiple time-points using different scanners. However, LVM is notably susceptible to interobserver variation, and this should be carefully considered if similar evaluations are planned as part of multicenter or longitudinal investigations.

Contrast-enhanced magnetic resonance cholangiography using mangafodipir compared with standard T2W MRC sequences: a pictorial essay.

Mangafodipir, a manganese-containing hepatobiliary contrast agent, is excreted in bile. We review the principles and practice of a contrast-enhanced MRC technique using mangafodipir and compare it with standard T2-weighted magnetic resonance cholangiography (MRC) sequences. Potential applications include the evaluation of leaks and strictures; the assessment of drainage in normal, surgically by-passed, stented and obstructed biliary systems; the diagnosis of cholecystitis; and the evaluation of normal and variant biliary anatomy.

Spiral laminar flow in the abdominal aorta: a predictor of renal impairment deterioration in patients with renal artery stenosis?

BACKGROUND: Spiral or helical arterial blood flow patterns have been widely observed in both animals and humans. The absence of spiral flow has been associated with carotid arterial disease. The aim of this study was to detect the presence of aortic spiral flow using magnetic resonance imaging (MRI) and to evaluate the relationship of the presence of spiral aortic flow with renal arterial disease and renal function in the follow-up of patients with suspected renal atheromatous disease. METHODS: Prospective study of 100 patients with suspected renal arterial disease and 44 patient controls. Using a 1.5 T MRI unit (Siemens Symphony), phase contrast flow quantification and three-dimensional contrast enhanced MR angiography of the abdominal aorta were performed. Renal arterial stenoses (RAS) were classified minimal, moderate or severe. Renal function was followed at 3 months before and 6 months after MRI. RESULTS: Non-spiral flow was more prevalent in patients with more severe RAS. Renal impairment progressed significantly in severe RAS without spiral flow (P = 0.0065), but did not progress significantly in severe RAS with spiral flow (P = 0.12). In minimal or moderate RAS with or without spiral flow there was no significant progression (P = 0.16, 0.13, 0.47, 0.092, respectively). CONCLUSIONS: Aortic spiral blood flow can be assessed with MRI. Lack of aortic spiral blood flow in patients with severe RAS is associated with significant short-term renal function deterioration. Determination of blood flow patterns may be a useful indicator of renal impairment progression in patients with suspected renal artery stenosis.