Magnetic resonance evaluation of renal artery stenosis in a swine model: performance of low-dose gadobutrol versus gadoterate meglumine in comparison with digital subtraction intra-arterial catheter angiography.

PURPOSE: The aim of this study was to compare low-dose imaging with gadobutrol and gadoterate meglumine (Gd-DOTA) for evaluation of renal artery stenosis with 3-T magnetic resonance angiography (MRA) in a swine model. METHOD AND MATERIALS: A total of 12 experimental animals were evaluated using equivalently dosed gadobutrol and Gd-DOTA for time-resolved and static imaging. For time-resolved imaging, the time-resolved imaging with stochastic trajectories (TWIST) technique (temporal footprint, 4.4 seconds) was used; a dose of 1 mL of gadobutrol was injected at 2 mL/s and a dose of 2 mL of Gd-DOTA was injected at both 2 and 4 mL/s. For a separate static acquisition, doses were doubled. The static scans were used for stenosis gradation and the time-resolved scans for comparison of enhancement dynamics, signal-to-noise ratio (SNR), and qualitative assessments. RESULTS: The average magnitude of difference in the stenosis measurements with static gadobutrol scans relative to digital subtraction intra-arterial catheter angiography (mean [SD], 7.4% [5.6%]) was less than with both the 2 mL/s (10.6% [6.2%]) and 4 mL/s (11.5% [7.8%]) Gd-DOTA MRA protocols. On time-resolved scans, peak signal-to-noise ratio was greatest with the gadobutrol protocol (P < 0.05), and the gadobutrol TWIST scan was preferred to the TWIST Gd-DOTA scan in terms of image quality and stenosis visualization in every case for every reader. CONCLUSION: Low-dose gadobutrol (~0.05 mmoL/kg) contrast-enhanced MRA results in improved accuracy of renal artery stenosis assessments relative to equivalently dosed Gd-DOTA at 3 T.

Persistent increase in cardiac troponin I in Fabry disease: a case report.

BACKGROUND: Hypertrophic cardiomyopathy is a frequent manifestation in Fabry disease (FD) - an X-linked lysosomal storage disorder caused by reduced activity of the enzyme α-galactosidase A. In FD an elevation of specific cardiac biomarkers, such as cardiac troponin I (cTNI) has been reported in case of clinical manifestation suggestive of myocardial ischemia. In diagnosing acute myocardial infarction cTNI is considered the most reliable parameter. CASE PRESENTATION: In the referred case we present a 59 years old female patient with the diagnosis of FD presenting with persistently increased cTNI level (lowest value 0.46 ng/ml, highest value 0.69 ng/ml; normal range <0.05 ng/ml) over a period of 5 months lacking cardiac clinical signs. Since renal insufficiency did not explain the degree of cTNI elevation, this was interpreted as a result of cardiac involvement in FD. Cardiac MRI showed marked left ventricular hypertrophy and focal late Gadolinium enhancement. CONCLUSIONS: Our case report demonstrates a persistent cTNI release in FD with cardiac involvement. Proving the persistence in a symptom free interval, it might be related to a direct damage of myocytes. In FD cTNI could serve as a beneficial long term parameter providing new perspectives for screening strategies.

Fecal elastase 1 measurement compared with endoscopic retrograde cholangiopancreatography for the diagnosis of chronic pancreatitis.

INTRODUCTION: Indirect tests of exocrine pancreatic function are thought to be of little sensitivity and specificity in mild to moderate insufficiency as compared with direct function tests. Direct tests, which are claimed to be the "gold standard" of functional diagnosis, are too complicated to be performed on great numbers of patients and are not standardized. AIMS: To characterize the use of an indirect function test (fecal elastase 1 measurements determined independently from a direct test), in this study we compared it with the gold standard of morphologic diagnosis, endoscopic retrograde cholangiopancreatography (ERCP). METHODOLOGY: Data for 213 patients who underwent ERCP (104 males and 109 females; mean age, 54 years [8-89]) were collected prospectively, including fecal elastase 1 measurements and clinical and ERCP data. RESULTS: Elastase 1 findings correlated with pancreatic duct changes (p < 0.05). At a cutoff point of 200 microg/g, the positive predictive value of elastase 1 measurement for moderate/severe duct changes was 90.4%, and for any duct changes it was 96.8%. The sensitivity was only 45.3% for any duct changes but 76.5% for severe changes. Specificity for moderate/severe changes was 86%. CONCLUSION: Fecal elastase 1 measurements appear to be valuable for characterizing patients at high risk for chronic pancreatitis, even if their sensitivity is lower than that of direct tests.