[New solutions for an old problem : Current developments in oral contrast agents]

BACKGROUND

Several radiological societies in Europe have so far spoken out in favor of MRI of the small intestine over CT, since MRI is said to provide more detailed image information. Due to the limited availability of MRI machines, long waiting times arise for many patients who clinically require small bowel imaging.

OBJECTIVES

These circumstances guided our search for an improved CT technique that would provide scans that mimic the image impression of T1 sequence in MRI, i.e. with IV contrast-enhanced intestinal wall versus low/no signal lumen.

MATERIAL AND METHODS

The oral use of fat or oil is poorly tolerated by patients, as is the placement of a naso-duodenal tube for air insufflation. We have now succeeded in creating a foamy drink with 44% air content, which is kept stable by protein together with buffers, and can be easily administered orally. CT with the Lumentin® beverage as bowel filling agent has been tested on healthy adult volunteers; oncology patients; and Crohn's disease patients who, for comparison, also underwent MRI of the small bowel with conventional oral contrast.

RESULTS

The results so far with Lumentin® show a very good distribution throughout the entire small intestine with good lumen distension, images with strongly enhanced contrast of the intestinal mucosa, and lesions that are detected at the same or increased frequency as compared with MRI. Side effects were few and mild, and overall fewer than with commonly used oral agents. Lumentin's foamy consistency was unfamiliar to a few patients, but it wasn't difficult to drink.

CONCLUSIONS

The new and innovative luminal HU-negative contrast agent Lumentin® improves the diagnostic CT image quality. In addition, Lumentin® experimental MRI tests have provided promising results, which are currently leading to further clinical MRI studies.

[Noninvasive mapping for catheter ablation of arrhythmias using the CardioInsight™ ECG vest]

BACKGROUND

CardioInsight™ is a noninvasive three-dimensional mapping system technology which offers a unique method for arrhythmia characterization and localization. With a 252-lead ECG vest on the patient's torso and a noncontrast CT scan, epicardial potentials are detected and by means of reconstruction algorithms activation and phase maps are created, offering a deeper understanding of localization and mechanisms of arrhythmias including atrial fibrillation without the need for an endocardial catheter.

MATERIALS AND METHODS

The system has proven to be accurate and applicable in the clinical setting of accessory pathways, premature ventricular contractions (PVC), atrial tachycardias and atrial fibrillation. Beat-to-beat analysis offers detection and thus a therapeutic approach for arrhythmias which occur only paroxysmally such as supraventricular extrasystoles, atrial bursts or PVCs. Another advantage is the simultaneous display of various heart chambers such as the left and right atrium. However, major multicenter prospective randomized data are still lacking.

CONCLUSION

If in the future noninvasive mapping could be achieved with MRI and if the technology was compatible with invasive mapping systems so that catheter positioning and noninvasive maps can be merged, the authors believe that this would represent a new dimension of mapping technology and ablation strategy of arrhythmias.