Foreign body ingestion among children is common and most usually pass through the gastrointestinal tract without requiring any intervention. Magnets, however, pose a greater threat especially when more than one are ingested. We report a case of multiple bowel perforation secondary to ingestion of magnetic beads in a 3-year-old.
Magnets

Ramping-up is the magnet current injection procedure which is under the control of resistance, voltage, current lead temperature, magnet pressure, temperature and so on. In this procedure, the factors related to the stability of the magnet such as, magnet temperature, pressure and currents are constantly changing. This procedure is the main step which the magnet-quench occurs in. This study uses the data collected during 7 years and SIMENS MRI ramping-up theory, in order to help engineers understand the key factors to reduce the magnet quench during the ramping up procedure.
Magnets ; Temperature

T1-, and T2-weighted imagings and FLAIR (fluid attenuated inversion recovery) imaging are fundamental imaging methods in the brain. T1-weighted imaging is a spin-echo sequence with short TR and short TE and produces the tissue contrast by different T1 relaxation times. In other words, short TR maximizes the difference of the longituidinal magnetization recovery between the tissues. T2-weighted imaging is a spin-echo sequence with long TR and long TE and produces the tissue contrast by different T2 relaxation times. Long TE maximizes the difference of the transverse magnetization decay between the tissues. FLAIR is an inversion recovery sequence using 180 degree inversion pulse. 2500 msec of inversion time is applied to suppress the CSF signal.
Brain ; Magnets ; Relaxation

Although MR imaging is generally applicable to depict knee joint deterioration it, is sometimes occurred to mis-read and mis-diagnose the common knee joint diseases. In this study, we employed magnetization transfer ratio (MTR) method to improve the diagnosis of the various knee joint diseases. Spin-echo (SE) T2-weighted images (TR/TE 3,400-3,500/90?100 ms) were obtained in seven cases of knee joint deterioration, FSE T2-weighted images (TR/TE 4,500-5,000/100?108 ms) were obtained in seven cases of knee joint deterioration, gradient-echo (GRE) T2-weighted images (TR/TE 9/4.56/50degrees flip angle, NEX 1) were obtained in 3 cases of knee joint deterioration, In six cases of knee joint deterioration, fat suppression was performed using a T2-weighted short T1/tau inverse recovery (STIR) sequence (TR/TE =2,894-3,215 ms/70 ms, NEX 3, ETL 9). Calculation of MTR for individual pixels was performed on registration of unsaturated and saturated images. After processing to make MTR images, the images were displayed in gray color. For improving diagnosis, three-dimensional isotropic volume images, the MR tristimulus color mapping and the MTR map was employed. MTR images showed diagnostic images quality to assess the patients' pathologies. The intensity difference between MTR images and conventional MRI was seen on the color bar. The profile graph on MTR imaging effect showed a quantitative measure of the relative decrease in signal intensity due to the MT pulse. To diagnose the pathologies of the knee joint, the profile graph data was shown on the image as a small cross. The present study indicated that MTR images in the knee joint were feasible. Investigation of physical change on MTR imaging enables to provide us more insight in the physical and technical basis of MTR imaging. MTR images could be useful for rapid assessment of diseases that we examine unambiguous contrast in MT images of knee disorder patients.
Knee ; Knee Joint ; Magnets

BACKGROUND: LORETA (Low Resolution Electromagnetic Tomography) produces a three-dimensional current density mapping from digitized EEG (electroencephalography) data. A comparison between visual waveform analysis of scalp EEG and LORETA method may be helpful for the exact localization of epileptiform discharges. METHODS: Digital EEG data from 20 subjects showing epileptiform discharges that were localized in the left or right frontotemporal regions (F7, F8) were studied. Those EEG waves were recorded using international 10~20 system. Phase reversals in bipolar montage were converted to referential montage and waveforms were analyzed visually. Those spike waves were converted into three-dimensional potential density mapping by LORETA method and maximum negative potential density region was determined. RESULTS: The same localization in the frontotemporal region (F7, F8) between two methods was noted in 16 subjects (80.0%). The discordant localization by LORETA method was noted in 4 subjects (20.0%). In different localiza-tion subjects, their locations were frontopolar region (Fp1, Fp 2) in 2 subjects, lateral temporal region (T7, T8) in 1 and posterior temporal region (P7, P8) in 1 subject, respectively. CONCLUSIONS: Even though the localization of epileptiform discharges by visual waveform analysis is a traditional method, electrical potential density mapping by LORETA can be a useful adjunctive localization method. If detailed localization is needed, LORETA method should increase accuracy.
Electroencephalography ; Magnets* ; Scalp

In situ extracorporeal shock wave lithotripsy(ESWL) monotherapy was performed in 75 cases with ureteral stones using the Modulith SL 20 electromagnetic lithotriptor between December 1990 and July 1991. The results obtained were as follows: 1. The locations of stones were upper ureter in 36 (48%) cases, midureter in 4 (5.3%) and lower ureter in 35 (46.7%). 2. The average number of ESWL was 1.27 sessions. 3. The number of ESWL sessions increased in accordance with increment of stone size. 4. The success rate was 97.2% in upper ureteral. 100% in midureteral, and 97.1% in lower ureteral stones. 5. The final success rate according to stone size was not significantly different. 6. Success rate decreased relatively in cases of complete ureteral obstruction by stones. Therefore, in situ ESWL monotherapy is considered to be a convenient safe, and efficient procedure as the first applicable method for the treatment of all ureteral stones regardless of stone size and location, because the multiple repeated ESWL monotherapy increases the success rate without ureteral deterioration.
Magnets ; Shock ; Ureter* ; Ureteral Obstruction

No abstract available.
Magnetic Resonance Spectroscopy ; Magnetics ; Magnets

BACKGROUND: The optimal management of pain using magnetic irradiation modalities continues to attract considerable debate. Therefore, we conducted a randomized, double-blind, placebo-controlled clinical trial to determine the effectiveness of pulsed electromagnetic therapy for the treatment of chronic lower back pain. METHODS: Fifteen-minute sessions of active (n = 20) or placebo (n = 20) electromagnetic therapy were repeated 3 times a week for 3 weeks. Patients were assessed using the 11-point numerical rating scale and the revised Oswestry disability scores for up to 4 weeks after therapy. RESULTS: The active magnetic group showed significantly more pain reduction than the placebo group immediately after therapy and one and four weeks after therapy (P < 0.05). At 4 weeks after therapy percentage changes in NRS from baseline were 22 +/- 24% and 38 +/- 11% in the placebo and magnetic groups, respectively. The revised Oswestry disability percentage in the active magnetic group was also significantly improved (P < 0.05). CONCLUSIONS: Pulsed electromagnetic therapy provided pain relief and ameliorated disability in patients with chronic lower back pain. According to our results, pulsed electromagnetic therapy should be considered an important potential therapeutic tool for the conservative therapy of chronic lower back pain.
Humans ; Low Back Pain* ; Magnets*

No abstract available.
Magnetic Resonance Spectroscopy ; Magnetics ; Magnets

Naviculocuneiform coalition is one of uncommon tarsal coalitions and especially symptomatic cases which need operative treatment are rare. Authors report 2 cases of pediatric naviculocuneiform patients who showed symptomatic condition as mainly pain. Plain radiographs, computed tomography or magnetic resolution imaging study showed bony bridge in naviculo-medial cuneiform joint. After over six months conservative treatment, excision of coalition and interposition Tisseel(R) was performed for motion preservation and relief of pain.
Child ; Humans ; Joints ; Magnetics ; Magnets