PURPOSE: Within a clinically acceptable time frame, we obtained the high resolution MR images of the human brain, knee, foot and wrist from 3T whole-body MRI system which was equipped with the world first 3T active shield magnet. MATERIALS AND METHODS: Spin echo (SE) and Fast Spin Echo (FSE) images were obtained from the human brain, knee, foot and wrist of normal subjects using a homemade birdcage and transverse electromagnetic (TEM) resonators operating in quadrature and tuned to 128 MHz. For acquisition of MR images of knee, foot and wrist, we employed a homemade saddle shaped RF coil. Typical common acquisition parameters were as follows: matrix= 512x512, field of view (FOV) = 20 cm, slice thickness = 3 mm, number of excitations (NEX) = 1. For T1-weighted MR images, we used TR= 500 ms, TE = 10 or 17.4 ms. For T2-weighted MR images, we used TR=4000 ms, TE = 108 ms. RESULTS: Signal to noise ratio (SNR) of 3T system was measured 2.7 times greater than that of prevalent 1.5T system. MR images obtained from 3T system revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter. CONCLUSION: The present results demonstrate that the MR images from 3T system could provide better diagnostic quality of resolution and sensitivity than those of 1.5T system. The elevated SNR observed in the 3T high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the microscopic structural level under in vivo conditions. These images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods.
Brain ; Foot ; Humans ; Knee ; Magnetic Resonance Imaging* ; Magnets ; Signal-To-Noise Ratio ; Wrist

PURPOSE: The purpose of this study is to examine the frequency of posterior element injury in patients with traumatic thoraco-lumbar burst fractures and to evaluate the correlation between the MR imaging and CT findings. MATERIALS AND METHODS: The MR images of 38 patients with 39 thoraco-lumbar burst fractures and the results of the CT examinations of 28 patients with 29 fractures were retrospectively analyzed. Both procedures were performed within two weeks of injury. Twenty-one males and 17 females were included ; their average age was 51.3 (range, 11-75) years. MR images were evaluated for injury to the posterior ligamentous complex, comprising the supraspinous ligament(SSL), the interspinous ligament(ISL), the flaval ligament(FL), and the capsule of facets. Analysis of the CT findings focused on the posterior bony elements of the lamina, pedicle, spinous process, and facet joint. RESULTS: MR imaging revealed posterior ligamentous injuries in 18(46.2%) of 39 burst fractures ; there was tearing of the ISL in 15 cases(38.5%), of the SSL in 11(28.2%), of the capsule of facets in 11(28.2%), and of the FL in nine(23.1%). Among the 29 burst fracture cases examined by CT, posterior bony injuries were detected in 13(44.8%). Lamina and facet joint fractures were detected in six cases(20.7%), facet separation or dislocation in six(20.7%), and spinous process and pedicle fracture in one(3.4%). In 29 burst fracture cases, both MRI and CT were performed. Among the 18 cases in which MR imaging revealed posterior ligamentous injuries, CT failed to demonstrate posterior element fractures in seven. On the other hand, among the 13 cases in which CT indicated posterior bony fractures, MR failed to reveal posterior ligamentous injuries in two. CONCLUSION: Posterior element injury is frequently found in patients with traumatic thoraco-lumbar burst fractures demonstrated by MR imaging(46.2%) and CT(44.8%). Both MRI and CT are useful tools for the evaluation of posterior element injury, which determines the degree of instability of traumatic burst fracture.
Dislocations ; Female ; Hand ; Humans ; Ligaments ; Magnetic Resonance Imaging ; Male ; Retrospective Studies ; Zygapophyseal Joint

PURPOSE: With the use of localized, water-suppressed in vivo 1H magnetic resonance spectroscopy (MRS), we evaluated the proton metabolic alterations in patients with chronic alcoholism and healthy normal controls. MATERIALS AND METHODS: Patients with chronic alcoholism (N=10) and normal control subjects (N=10) underwent MRS examinations using a stimulated echo acquisition mode (STEAM) pulse sequence with 2X2X2 cm3 volume of interest (VOI) in the left cerebellum and basal ganglia. Proton metabolite ratios relative to creatine (Cr) were obtained using a Marquart algorithm. RESULTS: The specific feature in patients with chronic alcoholism was a significant decrease of N-acetylaspartate (NAA)/Cr ratio in the left cerebellum, compared with normal controls. No clear correlation of other metabolite ratios such as choline (Cho)/Cr and inositols (Ins)/Cr was established. CONCLUSION: Our preliminary study suggests that the reduction of NAA/Cr ratio may indicate neuronal loss in patients with chronic alcoholism. Thus, in vivo 1H MRS may be a useful modality in the clinical evaluation of patients with chronic alcoholism based on the proton metabolite ratios.
Alcoholism* ; Basal Ganglia ; Cerebellum ; Choline ; Creatine ; Humans ; Inositol ; Magnetic Resonance Spectroscopy* ; Neurons* ; Protons

PURPOSE: To analyze the radiologic findings of metastatic tumors of the breast. MATERIALS AND METHODS: We retrospectively analyzed the findings of mammography (n=12), ultrasonography (n=9) and CT (n=4) of 13 patients with metastatic tumors of the breast. Methods for confirmation were biopsy (n=8) and clinical follow-up (n=5). The patient's ages ranged from 24 to 63 (mean 43) years. RESULTS: Primary malignancies were contralateral breast cancer (n=3), non-Hodgkin's lymphoma (n=3), stomach cancer (n=2), uterine cervix cancer (n=1), laryngeal cancer (n=1), esophageal melanoma (n=1), malignant thymoma (n=1), and lung cancer (n=1). Patterns of metastasis from contralateral breast cancer and the stomach cancer were diffuse and infiltrative, while metastasis from other cancers was of the focal massforming type. The radiologic findings of metastasis from contralateral breast cancer (n=3) were diffuse skin thickening and increased density or echogenicity in the medial aspect of the breast, while in cases involving metastasis from stomach cancer (n=2) radiographs revealed extensive skin thickening, increased density or echogenicity, lymphedema and ipsilateral lymphadenopathy in the left breast. In cases of metastatic tumors to the breast in which focal masses were seen on mammography (n=7), marginal spiculation or microcalcification of the tumors was not present. In six such cases, ultrasonography revealed well-defined margin, posterior acoustic shadowing or an irregular thick echogenic boundary was not seen. In two patients who underwent CT scanning, well-defined masses with moderate contrast enhancement were present. CONCLUSION: Radiographs of metastatic tumors to the breast from contralateral breast cancer and stomach cancer showed diffuse infiltration. The metastatic tumors with focal masses showed oval to round, smooth-marginated, well-defined masses without spiculation or microcalcification on mammography, and a well-defined mass without posterior acoustic shadowing or irregular thick echogenic boundary on ultrasonography.
Acoustics ; Biopsy ; Breast Neoplasms ; Breast* ; Cervix Uteri ; Female ; Follow-Up Studies ; Humans ; Laryngeal Neoplasms ; Lung Neoplasms ; Lymphatic Diseases ; Lymphedema ; Lymphoma, Non-Hodgkin ; Mammography ; Melanoma ; Neoplasm Metastasis ; Retrospective Studies ; Shadowing (Histology) ; Skin ; Stomach Neoplasms ; Thymoma ; Tomography, X-Ray Computed ; Ultrasonography

PURPOSE: The purpose of this study was to find the optimum TE value for enhancing T2* weighting effect and minimizing the SNR degradation and to compare the BOLD effects according to the changes of TE in 1.5T and 3.0T MRI systems. MATERIALS AND METHODS: Healthy normal volunteers (eight males and two females with 24-38 years old) participated in this study. Each volunteer was asked to perform a simple finger-tapping task (sequential opposition of thumb to each of the other four fingers) with right hand with a mean frequency of about 2Hz. The stimulus was initially off for 3 images and was then alternatively switched on and off for 2 cycles of 6 images. Images were acquired on the 1.5T and 3.0T MRI with the FLASH (fast low-angle shot) pulse sequence (TR : 100ms, FA : 20degrees, FOV : 230mm) that was used with 26, 36, 46, 56, 66, 76ms of TE times in 1.5T and 16, 26, 36, 46, 56, 66ms of TE in 3.0T MRI system. After the completion of scan, MR images were transferred into a PC and processed with a home-made analysis program based on the correlation coefficient method with the threshold value of 0.45. To search for the optimum TE value in fMRI, the difference between the activation and the rest by the susceptibility change for each TE was used in 1.5T and 3.0T respectively. In addition, the functional T2* map was calculated to quantify susceptibility change. RESULTS: The calculated optimum TE for fMRI was 61.89+/-2.68 at 1.5T and 47.64+/-13.34 at 3.0T. The maximum percentage of signal intensity change due to the susceptibility effect in activation region was 3.36% at TE 66ms in 1.5T and 10.05% at TE 46ms in 3.0T, respectively. The signal intensity change of 3.0T was about 3 times bigger than that of 1.5T. The calculated optimum TE value was consistent with TE values which were obtained from the maximum signal change for each TE. CONCLUSION: In this study, the 3.0T MRI was clearly more sensitive, about three times bigger than the 1.5T in detecting the susceptibility due to the deoxyhemoglobin level change in the functional MR imaging. So the 3.0T fMRI is more useful than 1.5T.
Female ; Hand ; Healthy Volunteers ; Humans ; Magnetic Resonance Imaging* ; Male ; Thumb ; Volunteers

PURPOSE: To apply a distributed circuit theory, to develop a head-size transverse electromagnetic(TEM) resonator coil for a home-built 3T whole-body MRI system and to report an efficiency of the coil. MATERIALS AND METHODS: The dimension of TEM resonator with 16 cavity element, the diameter of copper rod was 0.63cm and its length was 13.75cm. As raw materials, the purity of copper rod was 98% and the dielectric constant of teflon was 2.08. RESULTS: The TEM head-size resonator with 16cavity elements exhibiting 9-mode resonances was robust to the surrounding influences owing to the self-shielding structure. The isolation of quadrature with a human brain was 364 and the ratio of Q(unloaded/Q(loaded) was 2.9. CONCLUSION: It was successfully demonstrated that the TEM head-size resonator with high Q factor can provide high quality MR images at 3T MRI system. Also, the TEM resonator coil has an advantage for a fine tune with length adjustment of each cavity elements. Thus, it is expected that the TEM resonator at 3T, even higher field could be used in the clinical and research studies in near future.
Brain ; Copper ; Head* ; Humans ; Magnetic Resonance Imaging* ; Polytetrafluoroethylene

PURPOSE: To evaluate the efficacy of power Doppler ultrasonography (PDUS) in depicting renal infarction inrabbits during experimental renal segmental arterial occlusion, and to compare the results with those of CTscanning. MATERIALS AND METHODS: In 28 rabbits weighing 2.5-4kg, the segmental renal artery was occluded throughthe left main renal artery by embolization with Ivalon (Nycomed, Paris, France). Power Doppler ultrasonography andspiral CT scanning were performed before and at 2, 5, 8, 15, and 24 hours, and 3 and 7 days after occlusion of thesegmental renal artery. The location of infarcted areas and collaterals, as seen on PDUS and CT scans, wasevaluated by two radiologists. RESULTS: In all cases, as seen on power Doppler ultrasonography, infaretedareas-when compared with normal parenchyma, clearly demonstrated wedge-shaped perfusion defects in the kidney. Thelocation of the lesion closely corresponded to the location seen during CT scanning. After renal arterialocclusion, transiently congested capsular arteries, which were named 'capsular sign', were seen in 63% ofrabbits in the two and five-hour groups. No significant cortical rim sign was demonstrated on power Dopplerultrasonography, though it was noted on spiral CT at 15 and 24 hours, and 3 and 7 days after renal arterialocclusion. CONCLUSION: Power Doppler ultrasonography was useful for the diagnosis of renal infarction. Congestedcapsular artery seen in the early stage of renal infarction might be a characteristic finding of this condition,as seen on power Doppler ultrasonography.
Animals ; Arteries ; Diagnosis ; Estrogens, Conjugated (USP) ; Infarction ; Kidney ; Perfusion ; Rabbits ; Renal Artery* ; Tomography, Spiral Computed ; Tomography, X-Ray Computed ; Ultrasonography* ; Ultrasonography, Doppler

PURPOSE: The purpose of this study was aimed to evaluate BOLD(blood oxygen level dependent) contrast fMRI(function MR imaging) in the occipital lobe and to compare with the metabolic changes based on 1H MRS(MR spectroscopy) and MRSI(MR spectroscopic imaging) before and after visual stimulation MATERIALS AND METHODS: Healthy human volunteers(eight males and two females with 24-30 year age) participated in this study. All of the BOLD fMRI were acquired on a 1.5T MR with EPI during supervised visual stimulation in the occipital lobe. The red flicker with 8Hz was used for visual stimulation. After imaging acquisition, the MR images were transferred into unix workstation and processed with home made analysis software based on the correlation coefficient method. Proton MRS data sets were acquired from the same location based on the activation map. MRSI(magnetic resonance spectroscopic imaging) was also acquired to analyze the lactate changes before and after stimulation. RESULTS: The activation maps were successfully produced by BOLD effect due to visual stimulation. NAA(N-acetyle aspartate)/Cr(creatine) ratio varied only from 1.790.28 to 1.880.20 in activation area before and after stimulation. However, the signal intensity of lactate was elevated 9.484.38times higher than before activation. Lactate metabolite images were consistent with the activation maps. CONCLUSION: The BOLD contrast fMRI is enough sensitive to detect the activated area in human brain during the visual stimulation. Lactate metabolite map presents the evidence of lactate elevation on the same area of activation.
Brain ; Dataset ; Female ; Humans ; Lactic Acid ; Magnetic Resonance Imaging* ; Male ; Occipital Lobe ; Oxygen ; Photic Stimulation* ; Protons ; Spectrum Analysis*

Diffuse skin thickening of the breast is produced by lymphedema usually secondary to obstruction of theaxillary lymphatics. On physical examination, the affected breast is, due to increased fluid content, larger,heavier, and of higher overall density. Mammography reveals an increased coarse reticular pattern. Thickening ofthe skin can have many causes. It may be a result of tumor invasion or a tumor in the dermal lymphatics; orbecause of lymphatic congestion through obstruction of lymphatic drainage within the breast, in the axilla, orcentrally in the mediastinum. Further causes may be congestive heart failure, benign inflammation, primary skinprocesses such as psoriasis, or systemic diseases which involve the skin. Mammographic appearance is known to benonspecific. Ultrasound can demonstrate skin thickening directly, but despite some reports suggesting that thecause of skin thickening can be inferred from the results of ultrasound, this is not usually of practicalimportance. The purpose of this study is to review the causes of skin thickening of the breast and to usemammography and US to differentiate the causes.
Axilla ; Breast Diseases* ; Breast* ; Diagnosis, Differential* ; Drainage ; Estrogens, Conjugated (USP) ; Heart Failure ; Inflammation ; Lymphedema ; Mammography* ; Mediastinum ; Physical Examination ; Psoriasis ; Skin* ; Ultrasonography*

PURPOSE: To reduce ethanol reflux from the needle channel by injecting rat blood immediately after theinjection of ethanol into rat liver. MATERIALS AND METHODS: The first experiment involved 33 rat livers whichwere divided into four groups (three livers in group 1 ; ten in groups 2, 3, and 4). Group 1 animals were used ascontrols, and 0.1ml saline was injected into the liver ; in group 2, ethanol-Tc-99m-O4- mixed solution (0.1 ml,0.2 mCi) was injected into the liver ; in groups 3 and 4, the needle channel was blocked with 0.02 ml of freshblood and old blood, respectively, after the injection of ethanol. After removing the needle, a 3cm round filterpaper was laid on each injection site to absorb refluxed ethanol-Tc-99m-O4- mixed solution from the liver, andeach paper was then counted by a gamma camera unit. In the second experiment, 33 rats were divided into fourgroups (three rats in group 1 ; ten in groups 2, 3, and 4). Group 1 animals were used as controls, and afterexposing the left lateral lobe of the liver, 0.05 ml of saline was injected; in group 2, 0.05 ml of ethanol wasinjected into the liver in groups 3 and 4 the needle channel was blocked with 0.02 ml of fresh blood and oldblood, respectively, after the injection of ethanol. After ten days, peritoneal adhesions were scoredmacroscopically and microscopically. RESULTS: In the first experiment using ethanol-Tc-99m-O4- mixed solution,groups blocked with blood after the injection of mixed solution showed lower gamma counts than the group injectedwith mixed solution only (p-value = 0.0002). The group blocked with old blood showed the lowest count.Macroscopical and microscopical examination of peritoneal adhesions indicated that the grade of adhesion was lowerin groups blocked with blood than in the group injected with ethanol only (p-value = 0.0261 and 0.0163,respectively). CONCLUSION: The above results suggest that an injection of blood after an injection of ethanol isa very effective way of preventing reflux from the liver.
Animals ; Ethanol* ; Gamma Cameras ; Liver ; Needles ; Rats*