PURPOSE: Numerous studies have been performed about the various safety consideration of magnetic resonance(MR). Multiple investigators have failed to reveal any deleterious defects of MR. On the other hand, several studies have demonstrated detectable biologic effects of high-field MR produces any morphologic changes on the cell membrane and intracellular ultrastructures in human peripheral blood lymphocytes in vitro. MATERIALS AND METHODS: Lymphocytes were isolated from peripheral blood of normal human adults by Ficoll-Hypaque density centrifugation. Exposure to MR was performed with 4.69T and 11.74T MR spectrometer with a radio frequency(RF) pulse of 200MHz and 500MHz. Exposure times varyed from 30 minutes to 3 hours. The cells were fixed immediately, 1, 3, 7 days after MR exposure. Morphologic evaluation was examined by transmission electron microscopy(TEM). RESULTS: Under TEM there was cell transformation including cellular membrane, nucleus and intracellular microorganelles on lymphocytes exposed to MR. The percentage of transformed lymphocytes was not significantly increased after 4.69T MR exposure, whereas the percentage of transformed lymphocytes was significant increased after 11.74T MR exposure(P<0.05) compared with that of control. The percentage of transformed lymphocytes was significantly increased at the long incubation period in control and MR exposure group(P<0.05). No change according to MR exposure time and RF pulse sequence was noted. CONCLUSION: Exposure to high-field MR induces morphologic transformations of lymphocytes in vitro. Additional studies have to be performed before definitive conclusion can be reached about the safety of high-field MR.
Adult ; Cell Membrane ; Centrifugation ; Hand ; Humans* ; Lymphocytes* ; Membranes ; Research Personnel

PURPOSE: Traumatic rupture of the diaphragm is not easy to diagnose and often delayed. Delayed diagnosis of diaphragmatic rupture accompanied by higher chances of strangulation of herniated viscera which may result in higher morbility and mortality. The purpose of this study was to evaluate diagnostic accuracy of spiral CT, MRI and US for the diagnosis of diaphragmatic rupture in an animal model. MATERIALS AND METHODS: Small, medium, and large sized transabdominal diaphragmatic ruptures were surgically made in experimental rabbits and then followed up with spiral CT, MRI, and US at 1 day, 3 day, and 1 week after operation. RESULTS: US was superior to MRI or spiral CT in diagnosis of diaphragmatic rupture(P<0.05). The sensitivity and specificity were 94.4% and 92.9% for US, 54.0% and 85.7% for MRI, and 46.0% and 78.6% for spiral CT, respectively. The size of laceration was not related to diagnostic sensitivity in US. Sensitively of MRI and spiral CT increased as the size of laceration were larger, but no statistical significant was present(P>0.05). All experimental animals developed pleural effusion or hemothorax one day after operation. In acute phase. US and MRI were more sensitive than spiral CT in detecting diaphragmatic rupture. Spinal CT was more sensitive than US and MRI in delayed phase but without statistical significance(P>0.05) In the experimental rabbits with accompanying visceral hernia through the diaphragmatic defect, diagnostic accuracy was found equally high among three image modalities(P>0.05). CONCLUSION: This study indicates that US is the most accurate diagnostic method in detecting injury to the diaphragm in a rabbit model. The findings obtained in this experimental study can be applied to the diaphragmatic rupture of human being.
Animals ; Delayed Diagnosis ; Diagnosis* ; Diaphragm ; Hemothorax ; Hernia ; Humans ; Lacerations ; Magnetic Resonance Imaging ; Models, Animal ; Mortality ; Pleural Effusion ; Rabbits ; Rupture* ; Sensitivity and Specificity ; Tomography, Spiral Computed* ; Ultrasonography* ; Viscera

PURPOSE: To evaluate the diagnostic role of a three-dimensional MR cholangiopancreatography(MRCP) over endoscopic retrograde cholangio- pancreatography(ERCP) in various extrah-epatic biliary disease. MATERIALS AND METHODS: MRCP and ERCP were performed in 45 consecutive patients with suspected extrahepatic biliary diseases. MRCP was obtained using a reverse fast imaging with a steady-state free precession (reverse FISP : PSIF) sequences, and then images were reconstructed by standard MIP algorithm. The predictability of biliary dilatation and level of obstruction of MRCP was evaluated using ERCP as a gold standard. The accuracy distinguishing malignant from benign lesions, and overall diagnostic accuracy were compared between MRCP and ERCP. RESULTS: The sensitivity, specificity and accuracy of MRCP in predicting biliary dilatation were 94.6%, 75.0% and 91.1%, respectively. The level of obstruction was accurate in 87.0% with MRCP. The sensitivity, specificity and accuracy MRCP and ERCP in distinguishing malignant from benign lesions were 76.2%, 87.5% and 82.2% and 71.4%, 83.3% and 77.8%, respectively. The overall diagnostic accuracy was 60.0% with MRCP and 55.6% with ERCP. CONCLUSION: 3D MRCP shows a good diagnostic value compared to that of ERCP, and can replace a ERCP.
Cholangiopancreatography, Endoscopic Retrograde* ; Dilatation ; Humans ; Sensitivity and Specificity

PURPOSE: To compare the effectiveness of the in-phase(IP) sequence and the opposed-phase(OP) sequence in the detection of focal hepatic lesions in the single breath-hold hepatic MR imaging with fast gradient T1-weighted pulse sequences. MATERIALS AND METHODS: If and OP T1-weighted breath-hold imaging was performed using fast gradient echo sequences in 45 patients referred for known focal hepatic lesions, in which 78 lesions were detected. There blind readers independently reviewed the images for lesion detectability. The signal-to-noise ratio(SNR) of the liver, the lesion-to-liver contrast-to-noise ratio(CNR) and the liver-to-spleen CNR were also compared. A consensus was reached by three readers to determine which sequence is better in image quality. RESULTS: On OP images, 61(78%), 61(78%), and 63(89%) lesions were correctly identified for reader 1, 2 and 3, respectively. On IP images, 66(85%), 65(83%), and 65(93%) lesions were detected for each reader, respectively. When two image sets were combined, 71(91%), 69(88%), and 76(97%) lesions respectively were detected for each reader. In cases of hepatocellular carcinoma, liver-to-lesion CNR was greater on the OP images(p<0.05), but in other lesions significant differences was not demonstrated. Liver-to-spleen CNR was higher in OP images(p<0.1), but the SNR of the liver was higher on the If images. CONCLUSION: Use of both If and OP imaging can be helpful to avoid erroneous missing of some focal hepatic lesions.
Carcinoma, Hepatocellular ; Consensus ; Humans ; Liver* ; Magnetic Resonance Imaging*

PURPOSE: To assess the usefulness of breath-hold fast MR imaging of liver with fat suppression (FS) by application of chemical saturation technique in the diagnosis of regional fatty changed suspected in sonography. MATERIALS AND METHODS: Thirteen patients who had focal lesions with diffuse, homogeneous signal changes after FS through chemical saturation technique without additional changes of imaging parameter during MR imaging of liver were selected. T1-weighed fast low-angle shot and T2-weighted turbo spin-echo sequences were obtained with or without FS during each single breath-holding session. Subjective changes of signal intensity between the pre-FS and the FS images were compared with the sonographic findings in each lesion. RESULTS: Seven lesions of decreased signal intensity after FS on T1 or T2-weighted images, including three lesions only at FS T1 images, were regarded as focal fat infiltration. All seven lesions had compatible sonographic findings as homogenously echogenic areas. Another six lesions of subjectively increased signal intensity including two lesions only at FS T2 images were regarded as focal fat sparing. All six lesions had sonographic findings as homogenous echo poor areas suggesting focal fat sparing. In cases regarded as fat infiltration, score changes were more prominent at FS T1 images than FS T2 images(p=0.0002). In cases regarded as fat sparing, score changes were more prominent at FS T2 images than FS T1 images(p=0.042). CONCLUSION: Breath-hold fast T1 and T2-weighted MR imaging with and without chemical saturation pre-pulse may be sufficient for characterization of regional fatty changes in the different ferential diagnosis of focal hepatic lesion found at sonography.
Diagnosis ; Humans ; Liver* ; Magnetic Resonance Imaging* ; Ultrasonography

PURPOSE: To analyze contrast-enhancement pattern of stomach cancer on dynamic MRI and to verify the efficacy of intravenous contrast agent in the evaluation of stomach cancer. MATERIALS AND METHODS: Twelve patients with proven stomach cancer underwent dynamic MRI, By using 1.0T scanner, we obtained precontrast FLASH images, and 30, 60, 90 second delay FLASH images after intravenous contrast injection. All patients ingested on liter of water and had intramuscluar injection of Buscopan just before MR study. For quantitative analysis we measured signal to noise ratio (S/N) of stomach cancer on each image, and signal difference to noise ratio (SD/N) between cancer and intraluminal fluid, cancer and the pancreas. For qualitative analysis two radiologists evaluated lesion conspicuity on each image by grading system(grade 0, 1, 2, 3: poor, fair, good, excellent). RESULTS: S/N of stomach cancer increased gradually by time(precontrast, 30, 60, 90 second delay:38.7, 42.5, 57.4, 65.7). SD/N between cancer and intraluminal fluid significantly increased after contrast enhancement(1.24, 25.01, 39.30, 45.89). SD/Ns between cancer and the pancreas were 10.5, 9.33, 9.99, 10.66 respectively. In qualitative analysis, precontrast images were better than postcontrast images for delineation of stomach cancer, Postcontrast images showed clear endo-luminal side of stomach cancer, but outer margin of stomach cancer was more distinct on precontrast images. CONCLUSION: Precontrast MR images are better than postcontrast MR images in the depiction of stomach cancer. Intravenous contrast agent is not imperative in the evaluation of stomach cancer.
Butylscopolammonium Bromide ; Humans ; Magnetic Resonance Imaging* ; Noise ; Pancreas ; Signal-To-Noise Ratio ; Stomach Neoplasms* ; Water

PURPOSE: The aim of this study was to find correlation between the expression of epidermal growth factor receptor (ECFR) and MR findings in the brain glioma. MATERIALS AND METHODS: MR features including edema, margin, necrosis, heterogeneity, hemorrhage and contrast enhancement were retrospectively analyzed with preoperative MR images in 41 patients with proven brain gliomas (8 low grade astrocytomas, 12 anaplastic astrocytomas, 21 glioblastoma multiformes). Immunohistochemical study of EGFR was done and their expressions were graded by both stained distribution and intensity. Correlation analysis between the MR features and EGFR expressions was done. RESULTS: Peritumoral edema was correlated with both distribution (r=0.71, p=0.00) and stain intensity (r=0.69, p=0.00) of EGFR expression. Other MR features showed no statistical correlation with EGFR expression. CONCLUSION: MRI is useful in evaluation of brain glioma, and peritumoral edema is useful findings that suggests EGFR expression as well as malignant histopathologic grade of the tumor.
Astrocytoma ; Brain ; Edema ; Epidermal Growth Factor* ; Glioblastoma ; Glioma* ; Hemorrhage ; Humans ; Magnetic Resonance Imaging ; Necrosis ; Population Characteristics ; Receptor, Epidermal Growth Factor* ; Retrospective Studies

PURPOSE: To assess the utility of magnetic resonance(MR) cerebral blood volume (CBV) map in the evaluation of brain tumors. MATERIALS AND METHODS: We performed perfusion MR imaging preoperatively in the consecutive 15 patients with intracranial masses (3 meningiomas, 2 glioblastoma multiformes, 3 low grade gliomas, 1 lymphoma, 1 germinoma, 1 neurcyotma, 1 metastasis, 2 abscesses, 1 radionecrosis ). The averages age of the patients was 42 years (22yr-68yr), composed of 10 males and 5 females. All MR images were obtained at 1.5T imager(Signa, GE Medical systems, Milwaukee, Wisconsin). The regional CBV map was obtained on the theoretical basis of susceptibility difference induced by first pass circulation of contrast media.(contrast media: 15cc of gadopentate dimeglumine, about 2ml/sec by hand, staring at 10 second after first baseline scan). For each patient, a total of 480 images (6 slices, 80 images/slice in 160 sec) were obtained by using gradient echo(GE) single shot echo-planar image(EPI) sequence (TR 2000ms, TE 50ms, flip angle 90degree, FOV 240x240, matrix 128x128, slice-thick/gap 5/2.5). After data collection, the raw data were transferred to GE workstation and rCBV maps were generated from the numerical integration of deltaR2* on a voxel by voxel basis, with home made software(deltaR2*=-ln(S/S0/TE). For easy visual interpretation, relative RGB color coding with reference to the normal white matter was applied and color rCBV maps were obtained. The findings of perfusion MR image were retrospectively correlated with Gd-enhanced images with focus on the degree and extent of perfusin and contrast enhancement. RESULTS: Two cases of glioblastoma multiforme with rim enhancement on Gd-enhanced T1 weighed image showed increased perfusion in the peripheral rim and decreased perfusion in the central necrosis portion. The low grade gliomas appeared as a low perfusion area with poorly defined margin, In 2 cases of brain abscess, the degree of perfusion was similar to that of the normal white matter in the peripheral enhancing rim and was low in the central portion. All meningiomas showed diffuse homogeneous increased perfusion moderate or high degree. One each of lymphoma and germinoma showed homogenously decreased perfusion with well defined margin. The central neurocytoma showed multifocal increased perfusion areas of moderate or high degree. A few nodules of the multiple metastasis showed increased perfusion of moderate degree. One radionecrosis revealed multiple foci of increased perfusion within the area of decreased perfusion. CONCLUSION: The rCBV map appears to correlate well with the perfusion state of brain tumor, and may be helpful in discrimination between low grade and high grade glioma. The further study is needed to clarify the role of perfusion MR image in the evaluation of brain tumor.
Abscess ; Blood Volume ; Brain Abscess ; Brain Neoplasms* ; Brain* ; Clinical Coding ; Data Collection ; Discrimination (Psychology) ; Female ; Germinoma ; Glioblastoma ; Glioma ; Hand ; Humans ; Lymphoma ; Magnetic Resonance Imaging* ; Male ; Meningioma ; Necrosis ; Neoplasm Metastasis ; Neurocytoma ; Perfusion* ; Retrospective Studies

PURPOSE: Functional MR imaging is the method of demonstrating changes in regional cerebral blood flow produced by sensory, motor, and any other tasks. Functional MR of visual cortex os performed as a patient stares a photic stimulation, so adaptable photic stimulation is necessary. The purpose of this study to evaluate whether the size of photic stimulation can affect the degree of visual cortex activation. MATERIALS AND METHODS: Functional MR imaging was performed in 5 volunteers with normal visual acuity. Photic stimulator was made by 39 light-emitting diodes on a plate ,operating at 8 Hz. The sizes of photic stimulator were full field, half field and focal central field. The MR imager was Siemens 1.5-T Magenton Vision system, using standard head coil. Functional MRI utilized EPI sequence (TR/TE=1.0/51. 0msec, matrix No.=98x128, slice thickness=8mm) with 3sets of 6 imaging during stimulation and 6 imaging during stimulation and 6 imaging during rest, all 36 scanning were obtained. Activated images were obtained using postprocessing software(statistical analysis by Z-zone, and these images were combined with T-1 weighted anatomical images. The activated signals were quantified by numbering the activated pixels, and activation index was obtained by dividing the pixel number of each stimulator size with the sum of the pixel number of 3 study using 3 kinds of stimulators. The correlation between the activation index and the stimulation size was analysed. RESULTS: Mean increase of signal intensities on the activation area using full field photic stimulator was about 9.6%. The activation index was greatest on full field. second on half field and smallest in focal central field in 4, The index of half field was greater than that of full field in 1. The ranges of activation index were full field 43-73%(mean 55%), half field 22-40%(mean 32%), and focal central field 5-24%(13%). CONCLUSION: The degree of visual cortex activation increases with the size of photic stimulator.
Head ; Humans ; Magnetic Resonance Imaging* ; Photic Stimulation ; Visual Acuity ; Visual Cortex* ; Volunteers

PURPOSE: To evaluate the effect of global scaling analysis on brain activation for sensory and motor func-tional MR imaging study. MATERIALS AND METHODS: Four normal subjects without abnormal neurological history were included. Arm extension-flexion movement was used for motor function and 1 KHz pure tone stimulation was used for auditory function. Functional magnetic resonance imaging was performed at 3T MRI (GE, Milwaukee, USA) using BOLD-EPI technique and SPM2 was employed for data analysis. On data analysis, the brain activation images were obtained with and without global scaling by fixing other parameters such as motion correction and realignment. RESULTS: The difference in brain activation between no scaling and global scaling was not large in case of right upper extremity movement (p<0.000001). For auditory test, brain activation with global scaling showed larger activation than that of without global scaling (p<0.05). CONCLUSION: A caution must be taken into account when analyzing functional imaging data with global s-caling especially for functional study of small local BOLD signal change.
Arm ; Brain ; Magnetic Resonance Imaging* ; Statistics as Topic ; Upper Extremity