ABSTRACT
<p><b>BACKGROUND</b>Magnetic resonance imaging (MRI) is prone to be deformed by artifacts caused by the presence of metallic materials. The aim of this study was to evaluate the artifacts from galvano-ceramic and metal-ceramic crowns in MRI, in order to analyze their influences on diagnostic interpretation of MRI.</p><p><b>METHODS</b>Galvano-ceramic and metal-ceramic crowns (Bio98, Wiron99, SP-78, BioKC97) were fabricated with the same model. All materials were imaged by means of 1.5T MRI apparatus with three different sequences, T1-weighted spin-echo (T1-weighted SE), T2-weighted spin-echo (T2-weighted SE) and Gradient echo (GE). Mean and standard deviation of distilled water signal intensity (SI) around the sample in the region of interest (500 mm2) enclosing the whole artifacts were determined, and compared for evaluation of the homogeneity of signal intensity. Images around the sample were acquired and evaluated.</p><p><b>RESULTS</b>There were statistically significant differences in the values of signal intensity between acrylic resin control and BioKC97, Wiron99 in the three sequences (P<0.001). The mean values of signal intensity for Bio98, SP-78 were significantly different from that of acrylic resin control (RE) in GE sequence (P<0.001). No difference was showed between acrylic resin control and galvano-ceramic crown (P>0.05). Images showed that the greatest artifact was a 25 mm ring with distortion in Wiron99 in GE sequence.</p><p><b>CONCLUSIONS</b>This in vitro study suggested that galvano-ceramic crown had no influence on the MRI, while metal-ceramic crowns caused moderate artifacts in the MRI. Therefore, galvano-ceramic restoration is a valuable alternative in dentistry.</p>
Subject(s)
Humans , Artifacts , Ceramics , Crowns , Dental Alloys , Magnetic Resonance Imaging , Methods , MetalsABSTRACT
Objective To analyze CT findings correlated with pathologic findings in ectopic pancreas of the stomach.Methods CT scans of 15 surgically proven cases of ectopic pancreas of the stomach were reviewed,and enhanced CT scan was performed in 11 cases.CT findings were correlated with the pathologic findings.Results All cases had single lesion,and all lesions showed homogeneous density on plain scans without cystic or malignant changes.The size ranged from 1.3 to 3.1 cm,with mean diameter of (1.9? 0.2)cm.The lesions were round or oval in shape with broad base against the gastric wall.Two showed central umbilication sign.Only 2 cases were correctly diagnosed prior to operation and the rest were misdiagnosed or diagnosed indistinctly.The locations were in the gastric antrum in 11 cases,in the body in 3,and in fundus in one;The ectopic pancreas located in the greater curvature in 10,and in the lesser curvature in 5.Homogeneous or inhomogeneous strong enhancement similar to the pancreas was seen in 8 cases and they consisted mainly of pancreatic acini with the same histologic features as the pancreas.Three cases showed poor enhancement and consisted mainly of ducts and hypertrophied muscle,pancreatic acini were a minor component.Conclusion Ectopic pancreas of the stomach showed characteristic locations with the findings of snhmucosal diseases.Different enhancing patterns were correlated with their pathologic findings.
