Magnetic resonance cholangiography: past, present and future: a review.

INTRODUCTION: Magnetic resonance cholangio-pancreatography (MRCP) is a valuable method for the evaluation of biliary and pancreatic diseases and a valuable alternative to endoscopic retrograde cholangiopancreatography (ERCP). It is noninvasive and does not require the use of contrast material or ionizing radiation. Since its introduction in 1991, this technique has significantly improved in spatial resolution, now allowing the accurate assessment of the major bilio-pancreatic diseases. STATE OF THE ART: MRCP is commonly performed with heavily T2-weighted sequences in order to highlight static fluids, as those contained in dilated pancreatic and biliary ducts. Newest MR equipments allow to perform MRCP within 10-15 minutes, due to the availability of ultra-fast sequences. Currently, MRCP is widely performed as a primary imaging modality for the assessment of obstructive jaundice and other benign or malignant bilio-pancreatic ducts abnormalities. The primary MRCP application is the evaluation of biliary obstructions due to choledocholithiasis, iatrogenic strictures, cholangiocarcinoma or pancreatic carcinoma. Other MRCP applications include the assessment of the exocrine pancreatic function, following secretin stimulation. Whenever needed, the MRCP may be completed with a conventional contrast-enhanced magnetic resonance imaging (MRI) of the upper abdomen and functional studies as well, thus providing an all-in-one mophological and functional study of the pancreas and biliary system. More recent applications include the possibility of 3D reconstructions and the use of hepato-biliary contrast agents, that provide a higher definition of the biliary tree, both in pathologic and normal conditions. The introduction of 3Tesla magnets could provide higher anatomic detail. CONCLUSIONS: In the next years the role of MRCP will further expand, due to the availability of faster sequences, 3D imaging and functional studies.

Correlation between faecal calprotectin and magnetic resonance imaging (MRI) in the evaluation of inflammatory pattern in Crohn's disease.

BACKGROUND: Calprotectin, a major cytosolic protein of neutrophils, is increased in inflammatory bowel disease (IBD) and may be considered a suitable marker of intestinal inflammation. Abdominal MRI is becoming more frequently used for the evaluation of IBD patients. Aim of this study was to investigate the role of MRI in IBD for the assessment of disease activity in comparison with faecal calprotectin levels. PATIENTS AND METHODS: Twenty-four consecutive hospitalized pts (12 F, 12 M, median age: 56; range: 22-77) with a proven diagnosis of CD were studied. At the time of the MRI examination, pts provided a single stool sample for calprotectin measurement. Calprotectin was measured by ELISA (Calprest(R)). Pathological values were considered more than 50 microg/g. All pts underwent MRI, performed at 1.5 T, with HASTE T2w with and without fat-saturation, FLASH T1w fat-saturated sequences pre and post iv injection of 0.1 ml/kg of Gadolinium. Presence, degree and length of wall inflammation were evaluated. The MRI degree of wall inflammation was graded with a 0-3 scoring system (0=absent 1=light 2=moderate 3=severe) by considering findings observed on T1 post Gd and T2 fat-suppressed images, as well as the degree of wall thickness. The length of extension was considered as less than 15 cm, between 15 cm and 30 cm, or more than 30 cm. Spearman's correlation coefficient was used to evaluated differences in calprotectin levels among the groups obtained by MRI findings. RESULTS: Grade 0 MRI was found in 1 pt with a faecal calprotectin measurement of 206.25 microg/g; Grade 1 MRI was found in 4 pts with a median faecal calprotectin of 100 microg/g (5-325); Grade 2 MRI was found in 10 pts with a median faecal calprotectin of 243.75 microg/g (7.5-606.25); Grade 3 MRI was found in 9 pts with a median faecal calprotectin of 1012.5 microg/g (30-1268.8). A trend of positive correlation was therefore found between MRI scores of activity and calprotectin levels (p less than 0.0001) and between MRI scores of thickening of intestinal involvement and calprotectin levels (p = 0.005). No apparent correlation was observed between faecal calprotectin concentration and length. CONCLUSIONS: Data presenting show that faecal calprotectin levels well correlate with the degree of mucosal inflammation are in agreement with previous studies. Considering the correlation obtained between calprotectin level and MRI findings, we believe that MRI is helpful in assessing and monitoring the degree of disease in Crohn's disease.

Preoperative T and N staging of gastric cancer: magnetic resonance imaging (MRI) versus multi detector computed tomography (MDCT).

BACKGROUND AND AIM: Multi Detector Computed Tomography (MDCT) is widely used in the preoperative staging of gastric cancer. MRI has an emerging role in the evaluation of intestinal diseases, although its role in the staging of gastric cancers is still to be defined. The aim of our study was to compare the diagnostic accuracy of MDCT and Magnetic Resonance Imaging (MRI) in the diagnosis and preoperative staging of gastric cancer, in comparison with histopathology. MATERIALS AND METHODS: Twenty-five patients with an endoscopic diagnosis of gastric cancer underwent preoperative contrast-enhanced MDCT and MRI, blind to the results of endoscopy. MDCT (64 slices) was performed after oral administration of 800-1000 mL of tap water and scopolamine injection five minutes before the examination. The scan was performed in the axial plane before and after intravenous injection of iodinate contrast medium. Multiplanar reconstruction images were obtained on coronal and sagittal planes. MRI was performed with a 1.5 T Magnet, using the same patient's preparation, by acquiring T2-weighted HASTE sequences, with or without fat saturation (FS), True FISP (True fast imaging with steady state precession) and T1-weighted VIBE (Volumetric interpolated breath-hold examination) sequences, with and without FS, before and after contrast agent (gadolinium) i.v. injection. Gold standards (GS) were surgical and histopathological findings. Two groups of radiologists, blind each other, analyzed MRI images and MDCT findings, and related to GS results. RESULTS: Detection rate of gastric lesions and T staging for gastric cancer were similar for MRI and MDCT (92%); MRI imaging was superior than MDCT in staging the T parameter (60% versus 48%); the accuracy of MRI imaging and 64-MDCT did not differ significantly in the evaluation of N staging (68% versus 72%). CONCLUSIONS: Both MRI and MDCT were comparable in staging gastric cancer. MRI was more accurate in evaluation of T stage than MDCT, although both imaging modalities showed low accuracy in detection of early gastric cancer and in differentiation of T2 from T3 stage.