MR enterography with a new negative oral contrast solution containing maghemite nanoparticles.

AIM: The aim of this study was to test an oral contrast solution with maghemite for the magnetic resonance imaging of small bowel diseases. PATIENTS AND METHODS: The study sample included 3 cohorts: 17 healthy volunteers (group A), 22 patients with small bowel disease (group C). Both groups underwent MR enterography and 24 patients with small bowel disease (group B) underwent magnetic resonance cholecystopancreaticography. Various concentrations in 1000 ml vs 500 ml of experimental solution were tested. All cohorts completed questionnaires evaluating the solution characteristics and side-efects during and after drinking. RESULTS: A maghemite concentration of 800 mg /4 g bentonite in 1000 ml solution was sufficient for proper intraluminal lay-out. An experimental solution of 500 ml was sufficient for magnetic resonance cholecystopancreaticography and 1000 ml for MR enterography. There were no statistically significant differences between groups for taste, taste characteristic or appearance of the experimental solution. Side-effects experienced during drinking were: nausea (29.4%) and eructation (29.4%) in group A, in group B (42%) and diarrhoea (27.3%) in group C. Side-effects 2 h after drinking occured in group A (nausea 17.6%) and in group C (diarrhoea 47%). The best tolerance of experimental solution was found in group B with a higher median patient age than groups A and C. The experimental solution was evaluated more favorably in the older subjects (age over 50 years). CONCLUSION: The experimental oral solution with maghemite was well tolerated in all 3 groups. Our study supports its use in magnetic resonance practice.

Small bowel imaging - still a radiologic approach?

BACKGROUND: In recent years, there has been renewed interest in small bowel imaging using a variety of radiologic or endoscopic techniques. This article gives an overview and comparison of old and new techniques used in small bowel imaging. New imaging methods as computed tomography (CT), CT enteroclysis (CTEc), CT enterography (CTEg), ultrasound (US), contrast-enhanced ultrasound (CEUS), US enteroclysis, US enterography, magnetic resonance imaging (MRI), MR enteroclysis (MREc) and MR enterography (MREg) are compared with the older techniques such as small- bowel follow- through (SBFT), conventional enteroclysis (CE) and endoscopic techniques including push enteroscopy, ezofagogastroduodenoscopy (EGD), sonde enteroscopy, ileocolonoscopy, double-balloon enteroscopy, intraoperative enteroscopy and wireless capsule enteroscopy (WCE). METHODS: Systematic scan of Pubmed, Medline, Ovid, Elsevier search engines was used.. Additional information was found through the bibliographical review of relevant articles. RESULTS: SBFT has only secondary role in small bowel imaging. US is still the method of choice in imaging for pediatric populations. US and CEUS are also accepted as a method of choice especially in inflammatory cases. CE has been replaced by new cross - sectional imaging techniques (CTEc/CTEg or MREc/MREg). CTEc combines the advantages of CT and CE. MREc combines the advantages of MRI and CE. Some authors prefer CTEg or MREg with peroral bowel preparation and they strictly avoid nasojejunal intubation under fluoroscopic control. MREc has better soft tissue contrast, showing it to be more sensitive in detecting mucosal lesions than CTEc in inflammatory diseases. CTEg/MREg are techniques preferred for patients in follow-up of the inflammatory diseases. The radiologic community is not unanimous however about their role in the imaging process. CTEc/MREc as well as CTEg/MREg are superior to endoscopic methods in the investigation of small-bowel tumors. WCE gives unparalleled imaging of the mucosal surface of the small bowel especially in the event of obscure gastrointestinal bleeding and inflammatory diseases. CONCLUSIONS: In a comparison of endoscopic and radiologic approaches, radiologic techniques are less invasive for patients, they take less time to investigate and allow imaging the entire small bowel. Some do not involve radiation exposure (US, MR). Endoscopic methods are more expensive, more invasive, need longer examination time and technical special skills but without radiation exposure. The greatest advantage of some endoscopic methods is the possibility of mucosal biopsy in one step with diagnostic examination (EGD, push enteroscopy, intraoperative enteroscopy, ileocolonoscopy).

Superparamagnetic maghemite nanoparticles from solid-state synthesis - their functionalization towards peroral MRI contrast agent and magnetic carrier for trypsin immobilization.

Nearly monodispersed superparamagnetic maghemite nanoparticles (15-20nm) were prepared by a one-step thermal decomposition of iron(II) acetate in air at 400 degrees C. The presented synthetic route is simple, cost effective and allows to prepare the high-quality superparamagnetic particles in a large scale. The as-prepared particles were exploited for the development of magnetic nanocomposites with the possible applicability in medicine and biochemistry. For the purposes of the MRI diagnostics, the maghemite particles were simply dispersed in the bentonite matrix. The resulting nanocomposite represents very effective and cheap oral negative contrast agent for MRI of the gastrointestinal tract and reveals excellent contrast properties, fully comparable with those obtained for commercial contrast material. The results of the clinical research of this maghemite-bentonite contrast agent for imaging of the small bowel are discussed. For biochemical applications, the primary functionalization of the prepared maghemite nanoparticles with chitosan was performed. In this way, a highly efficient magnetic carrier for protein immobilization was obtained as demonstrated by conjugating thermostable raffinose-modified trypsin (RMT) using glutaraldehyde. The covalent conjugation resulted in a further increase in trypsin thermostability (T(50)=61 degrees C) and elimination of its autolysis. Consequently, the immobilization of RMT allowed fast in-solution digestion of proteins and their identification by MALDI-TOF mass spectrometry.