• Investigative Magnetic Resonance Imaging
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• v.7 no.1
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• pp.39-46
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• 2003

Purpose : To develop a theoretical model for magnetic relaxation behavior of the superparamagnetic nano-particle agent, which demonstrates multi-functionality such as liver- and lymp node-specificity. Based on the developed model, the computer simulation was performed to clarify the relationship between relaxation time and the applied magnetic field strength. Materials and Methods : The ultrasmall superparamagnetic iron oxide (USPIO) was encapsulated with biocompatiable polymer, to develop a relaxation model based on outsphere mechanism, which was resulting from diffusion and/or electron spin fluctuation. In addition, Brillouin function was introduced to describe the full magnetization by considering the fact that the low-field approximation, which was adapted in paramagnetic case, is no longer valid. The developed model describes therefore the T1 and T2 relaxation behavior of superparamagnetic iron oxide both in low-field and in high-field. Based on our model, the computer simulation was performed to test the relaxation behavior of superparamagnetic contrast agent over various magnetic fields using MathCad (MathCad, U.S.A.), a symbolic computation software. Results : For T1 and T2 magnetic relaxation characteristics of ultrasmall superparamagnetic iron oxide, the theoretical model showed that at low field (<1.0 Mhz), $\tau_{S1}(\tau_{S2}$, in case of T2), which is a correlation time in spectral density function, plays a major role. This suggests that realignment of nano-magnetic particles is most important at low magnetic field. On the other hand, at high field, $\tau$, which is another correlation time in spectral density function, plays a major role. Since $\tau$ is closely related to particle size, this suggests that the difference in R1 and R2 over particle sizes, at high field, is resulting not from the realignment of particles but from the particle size itself. Within normal body temperature region, the temperature dependence of T1 and T2 relaxation time showed that there is no change in T1 and T2 relaxation times at high field. Especially, T1 showed less temperature dependence compared to T2. Conclusion : We developed a theoretical model of r magnetic relaxation behavior of ultrasmall superparamagnetic iron oxide (USPIO), which was reported to show clinical multi-functionality by utilizing physical properties of nano-magnetic particle. In addition, based on the developed model, the computer simulation was performed to investigate the relationship between relaxation time of USPIO and the applied magnetic field strength.

• Journal of the Korean Arthroscopy Society
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• v.12 no.3
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• pp.172-179
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• 2008

Purpose: To evaluate the functional and structural results of arthroscopic double-row repair using combined knot-tying and knotless suture anchors in rotator cuff tears. Materials and Methods: From March 2006 to June 2007, twenty-one patients (15 males, 6 females; mean age 55.6 years; range 48 to 67) were included who underwent arthroscopic double-row repair for full-thickness tears of the rotator cuff following conservative treatment for a mean of 6.5 months (range 3 to 11). The tear size was carefully inspected arthroscopically and we found 2 small, 13 medium and 6 large-sized rotator cuff tears, with a mean tear size of 2.5cm(range 1.8 to 3.2). The repair constructs were consisted of horizontal mattress sutures using conventional knot-tying suture anchors medially and simple suture at the same level of medial row stitch with Bioknotless RC anchors (DePuy Mitek, Norwood, MA) as lateral row. Clinical and functional evaluations were made according to the range of motion, the ASES, UCLA scale and the isokinetic strength testing. Postoperative cuff integrity was determined through magnetic resonance imaging. The mean follow-up was 15 months (range 13 to 24). Results: The average clinical outcome scores and strength were all improved significantly at the time of the final follow-up (p < 0.01). Nineteen patients (90%) were satisfied with the result of the treatment. In 17 of 21 patients (81%) were judged to reveal healed tendon on magnetic resonance imaging at a mean of 7 months postoperatively. There were no significant functional differences according to the preoperative tear size (p<0.01), but large-sized tear shows less favorable structural results in 3 out of 6 cases(50%). Conclusion: Our results document the usefulness and variability of arthroscopic double-row rotator cuff repairs comparable to the results of the other types of double-row repairs.

• Clinics in Shoulder and Elbow
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• v.12 no.2
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• pp.173-179
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• 2009

Purpose: On the hypothesis that the acromion morphology is changed according to the its site, we identified the morphology of the acromion on the oblique slices of MRI and we investigated the association of the acromial shape with the clinical stages of rotator cuff disorder on the magnetic resonance (MR) images. In addition, we compared the acromion morphology on MRI and simple X-rays. Material and Methods: The MR images of seventy one patients with rotator cuff disorder and who underwent arthroscopic surgery were compared with that of a control group of sixteen patients who didn't have rotator cuff disorder on MRI. On three subsequent oblique sagittal slices from the lateral edge of the acromion (S1, S2 and S3), each acromion morphology on the MRI slices was classified according to Epstein et al: flat, curved or hooked. We investigated the changing parttern of the acromion shape and we compared the acromion shape on MRI and that on simple X-rays. We classified the rotator cuff tear by the severity: bursitis, partial thickness tear or full thickness tear. We investigated which acromial type on the MRI oblique slice was associated with the severity of rotator cuff disease. Results: Changes of the acromial shape occurred in 54 patients (76.1%). The most frequent pattern was that the types are same on S1 and S2 and different on S3 (22 cases, 31.0%). The acromial type on S1 and S2 was significantly associated with the severity of rotator cuff disorder (p=0.001 and 0.022), respectively. There was no reliability of the acromial shape on MRI and roentgenography (p>0.05) Conclusion: The type of acromion changed from lateral to medial. Among the three positions, the shape of the acromion on S1 and S2 had meaningful correlation with the clinical stage of rotator cuff disorder. There was no statistical correlation of the acromial shape between MRI and simple X-ray.

• Journal of the Korean Society of Radiology
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• v.81 no.6
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• pp.1412-1423
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• 2020

Purpose Some patients with neonatal seizures show diffuse, symmetric diffusion-restricted lesions in the cerebral white matter. The aim of this study was to describe clinical and imaging findings of patients with neonatal seizures who had diffuse, symmetric diffusion-restricted lesions without any structural or metabolic etiology. Materials and Methods A total of 56 neonates aged less than 1 week underwent brain magnetic resonance imaging (MRI) for evaluation of seizures from November 2008 to February 2017. After excluding 43 patients, 13 patients showed diffuse white matter abnormality on diffusion-weighted imaging. Initial and follow-up clinical and MRI findings were analyzed retrospectively. Results All 13 patients were born at full term. Among the ten patients who underwent a stool test for viruses, six were positive for rotavirus and one for astrovirus. MRI revealed diffuse, symmetric diffusion-restricted lesions distributed along the cerebral white matter, thalami, and midbrain variably. Conclusion Diffuse, symmetric diffusion-restricted lesions involving the cerebral white matter can be seen in patients with neonatal seizures without any structural or metabolic etiology. Rotavirus is commonly but not exclusively detected in these patients. Nevertheless, viral infection-associated encephalopathy should be considered for patients with characteristic clinical and MRI findings.

• The Journal of Korean Orthopaedic Ultrasound Society
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• v.1 no.2
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• pp.78-85
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• 2008

Purpose: The findings of preoperative magnetic resonance imaging (MRI) and ultrasonography (US) examination in the diagnosis of rotator cuff tear were then compared with the findings of arthroscopic examination, and to evaluate the postoperative integrity of rotator cuff using serial US examination. Methods: Between February and May 2008, 29 patients with rotator cuff tear had undergone preoperative US and MRI examination and subsequent arthroscopic examination. And the results of MRI and US were compared with intra-operative results of the arthroscopic examination. We observed the postoperative integrity of rotator cuff using serial (postoperative 2 weeks, 6 weeks, 3 months) US examination. Results: The sensitivity of US and MRI for identifying rotator cuff tear were 100% and 100%. The sensitivity of US and MRI were 95% and 82% in full thickness tear, and 50%, 33% in partial thickness tear, respectively. Overall accuracy of US and MRI were 86%, 69%. Among 22 patients were operated for full thickness tear, intra-operative gap formation was identified in 11 patients (50%, small to medium 2 cases, large to massive 9 cases) which were identified at 2 weeks postoperative US. We could find 5 re-tears (23%, small to medium 1 case, large to massive 4 cases) on 6 weeks postoperative US after passive range of motion (ROM) exercise, and could also find 7 re-tears (32%, small to medium 2 cases, large to massive 5 cases)on 3 months postoperative US after active ROM exercise. Conclusion: Serial US after arthroscopic rotator cuff repair was useful to differentiate intra-operative gap formation from postoperative re-tear. We found 5 retears (23%) at 6 weeks and 7 retears (32%) at 3 months postoperative US, it was useful to make treatment plan during postoperative rehabilitation.

• Neonatal Medicine
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• v.18 no.2
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• pp.310-319
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• 2011

Purpose: The aim of this study was to investigate the effect of perinatal risk factors on brain maturation and the relationship of brain maturation and neurodevelopmental outcomes with brain maturation scoring system in brain MRI. Methods: ELBWI infants born at the Seoul National University Children's Hospital from January 2006 to December 2010 were included. A retrospective analysis was performed with their medical record and brain MR images acquired at near full term. We read brain MRI and measured maturity with total maturation score (TMS). TMS is a previously developed anatomic scoring system to assess brain maturity. The total maturation score was used to evaluate the four parameters of maturity: (1) myelination, (2) cortical infolding, (3) involution of glial cell migration bands, and (4) presence of germinal matrix tissue. Results: Images from 124 infants were evaluated. Their mean gestational age at birth was 27.1${\pm}$2.1 weeks, and mean birth weight was 781.5${\pm}$143.9 g. The mean TMS was 10.8${\pm}$2.0. TMS was significantly related to the postmenstrual age (PMA) of the infant, increasing with advancing postmenstrual age (P<0.001). TMS showed no significance with neurodevelopmental delay, and with brain injury, respectively. Conclusion: TMS was developed for evaluating brain maturation in conventional brain MRI. The results of this study suggest that TMS was not useful for predicting neurodevelopmental delay, but further studies are needed to make standard score for each PMA and to re-evaluate the relationship between brain maturation and neurodevelopmental delay.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.2
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• pp.61-68
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• 2011

Purpose: We evaluated the clinical outcome after arthroscopic repair in full thickness rotator cuff tears with and without delamination. Materials and Methods: From March 2006 to October 2008, we included 48 consecutive shoulders (31 males, 17 females; mean age 57.6 years; 45~68) who had arthroscopic double row repair for fullthickness tears of the rotator cuff. Mean rotator cuff tear size was 2.8 cm (range: 1.2~3.6) and the techniques of tendon-to-bone fixation varied according to the presence of delamination; separate row fixations of bursal and articular layer were used in delaminated tear. The mean follow-up was 26 months (range: 18~33) and functional and structural results were evaluated by American Shoulder and Elbow Surgeons (ASES), University of California at Los Angeles (UCLA) scale, isokinetic strength testing and magnetic resonance imaging (MRI) obtained mean 8 months (range:6~13) postoperatively. The patterns of delamination, age, sex, symptom duration, size of tear, satisfaction rate, retear rate ware compared and significance was set at p values < 0.05. Results: Postoperative functional shoulder score improved significantly in 44 shoulders (91.7%). Delamination was observed in 15 shoulders (31%) and it extended proximally and posteriorly in the majority of shoulders, and the articular layer was thicker (8/15, 53%) and more retracted (9/15, 60%) compared with the superficial bursal layer. Final follow up functional shoulder scores showed no differences between non-delaminated and delaminated tears and the presence of delamination had no correlations with sex, symptom duration, tear size and satisfaction rate, however, older age had more delaminated tears (p=0.041). Follow up MRI in 29 shoulders revealed that fourteen (48%) shoulders had complete healing; nine (31%), partial healing; six (21%), complete retear but the half of the retear group showed favorable clinical results. 79% (15/19) in non-delaminated tear and 80% (8/10) in delaminated tear were judged as healed tendon on MRI and double-layer double row repairs in delaminated tears resulted in nearly same rate of structural integrity of single-layer double row repairs (p=0.165). Conclusion: The incidence of delamination in our series was 31% and older age had more delaminated tears. Sex, symptom duration, preoperative size of the tear, functional results and satisfaction rate had no significant correlations with the presence of delamination. Nearly the same postoperative structural integrity was noted in both delaminated and non-delaminated tears.

• Journal of the Korean Arthroscopy Society
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• v.15 no.2
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• pp.83-91
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• 2011

Purpose: Microfracture has been used as a first-line treatment to repair articular cartilage defects. In this study, a new technique using an extracelluar matrix biomembrane to cover the cartilage lesions after microfracture was evaluated in terms of cartilage repairability and clinical outcome compared with conventional microfracture technique in a prospective randomized trial. Materials and Methods: A total of 53 patients (59 cases) without osteoarthritis who had focal full thickness articular cartilage lesions were randomly assigned in two group. Seventeen patients (17 cases) underwent conventional microfracture procedure (control group) and thirty-six patients (42 cases) received microfracture and placing biomembrane cover (ArtiFilm$^{TM}$) concomitantly (experimental group). Clinical assessment was done through 6 months postoperatively using the subjective International Knee Documentation Committee IKDC questionnaire, and visual analog scale (VAS) for pain and satisfaction. Magnetic resonance imaging (MRI) was performed at 6 months after the operation in all patients. Results: In clinical outcomes, the significant difference was observed between both groups in IKDC, but not in VAS for pain and for satisfaction (final outcomes of IKDC, p=0.001; VAS for pain, p=0.074; VAS for satisfaction, p=0.194). The MRI showed good to complete defect fill (67 to 100%) in 33 patients (78.6%) of experimental group and 4 patients (23.5%) of control group, respectively. In control group, 9 of 17 patients (52.9%) showed poor defect fill (less than 33%), whereas 5 (11.9%) in experimental group (p=0.001). Assessment of peripheral integration revealed no gap formation in 35 patients (83.3%) in experimental group and 6 patients (35.3%) in control group (p=0.001). No serious complications or adverse effects related to the biomembrane were found. Conclusion: Good short-term follow-up clinical results were obtained in the group whose cartilage defects in the knee joint were covered with biomembrane after the microfracture, with the MRI findings confirming the excellent regeneration of the defective cartilage area. This suggests that the surgery to cover the defective area with biomembrane (ArtiFilm$^{TM}$) after the microfracture procedure is a safe, more effective treatment to induce cartilage regeneration.

• Journal of the Mineralogical Society of Korea
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• v.29 no.3
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• pp.155-165
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• 2016

Understanding the effect of boron content on atomic structures of boron-bearing multicomponent silicate melts is essential to reveal the atomistic origins of diverse geochemical processes involving silica-rich magmas, such as explosive volcanic eruption. The detailed atomic environments around B and Al in boron-bearing complex aluminosilicate glasses yield atomistic insights into reactivity of nuclear waste glasses in contact with aqueous solutions. We report experimental results on the effect of boron content on the atomic structures of sodium borate glasses and boron-bearing multicomponent silicate melts [malinkoite ($NaBSiO_4$)-nepheline ($NaAlSiO_4$) pseudo-binary glasses] using the high-resolution solid-state NMR ($^{11}B$ and $^{27}Al$). The $^{11}B$ MAS NMR spectra of sodium borate glasses show that three-coodrinated boron ($^{[3]}B$) increases with increasing $B_2O_3$ content. While the spectra imply that the fraction of non-ring species decreases with decreasing boron content, peak position of the species is expected to vary with Na content. Therefore, the quantitative estimation of the fractions of the ring/non-ring species remains to be explored. The $^{11}B$ MAS NMR spectra of the glasses in the malinkoite-nepheline join show that four-coordinated boron ($^{[4]}B$) increases as $X_{Ma}$ [$=NaBSiO_4/(NaBSiO_4+NaAlSiO_4)$] increases while $^{[3]}B$ decreases. $^{27}Al$ MAS NMR spectra of the multicomponent glasses confirm that four-coordinated aluminum ($^{[4]}Al$) is dominant. It is also observed that a drastic decrease in the peak widths (full-width at half-maximum, FWHM) of $^{[4]}Al$ with an addition of boron ($X_{Ma}=0.25$) in nepheline glasses. This indicates a decrease in structural and topological disorder around $^{[4]}Al$ in the glasses with increasing boron content. The quantitative atomic environments around boron of both binary and multicomponent glasses were estimated from the simulation results of $^{11}B$ MAS NMR spectra, revealing complex-nonlinear variation of boron topology with varying composition. The current results can be potentially used to account for the structural origins of the change in macroscopic properties of boron-bearing oxide melts with varying boron content.

• Economic and Environmental Geology
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• v.51 no.4
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• pp.345-358
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• 2018

In this study, we have performed electron probe micro analyzer (EPMA), X-ray differaction (XRD), inductively coupled plasma spectroscopy (ICP), Fourier transform Raman spectroscopy (FT-Raman), far-infrared (FIR), nuclear magnetic resonance (NMR), and pH-DO Analyses for characterizing medicinal mineralogy aspect of the black tourmaline (Shantung, china), black and pink tourmaline (Minas Geraris, Brazil), black touemaline (Daeyu mine, Korea). In addition, heating effects of the tourmaline sauna as well as the effects of tourmaline powder-added soap on skin troubles have been investigated. It has been revealed that chemical composition of the tourmaline is either high in Fe-, Al-, B-rich types. Ratio of the K-Ca, Na-K, and Fe-B reflects the component change property of solid solution. $CaO/CaO+Na_2O$ and MgO/FeO+MgO ratio show high positive correlation. When tourmaline reacts with distilled water, extended reaction time DO values approximately decrease and it stabilizes at DO = 10. Otherwise, pH values increase until 6 hours and it stabilizes at pH = 8 after 24 hours. Distilled water changes to alkaline when it reacts with tourmaline powder and particles. Tourmaline showed lower absorption spectrum strength and transmittance at short wave, where absorption spectrum wavelength and strength were determined by the content of the composition elements and characteristics of crystallography. Increase of the Fe content has been confirmed to be the cause for the reduction of irradiation. For the chemical composition and spectral property of the tourmaline particle samples, it has been found that Si and Fe contents show positive correlation with Far-Infrared irradiation, while Al and Mg contents show negative correlation. For tourmaline powder, it has been confirmed that $^{17}O-NMR$ FWHM (full width at half maximum) decreases when reacts with distilled water. Tourmaline sauna (approximately $100^{\circ}C$) was found to increase $0.5-1.5^{\circ}C$ of body temperature, average of 12 heartbeat, and 10mg Hg of blood pressure. Tourmaline soap had very good aesthetic effect to skin and was confirmed to have above the average improvements to skin troubles (e.g., allergy or atopy).