Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.

Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.

Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.

Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.

Magnetic resonance imaging (MRI)-related techniques can provide information related to the electrical properties of the body. Understanding the electrical properties of human tissues is crucial for developing diagnostic tools and therapeutic approaches for various medical conditions. This study reviewed the principles, development, and application of electrical conductivity mapping using MRI. To review the magnetic resonance electrical properties tomography (MREPT)-based conductivity mapping technique and its application to brain imaging, first, we explain the definition and fundamental principles of electrical conductivity, some factors that influence changes in ionic conductivity, and the background of mapping cellular conductivities. Second, we explain the concepts and applications of magnetic resonance electrical impedance tomography (MREIT) and MREPT. Third, we describe our recent technical developments and their clinical applications. Finally, we explain the benefits, impacts, and challenges of MRI-based conductivity in clinical practice. MRI techniques, such as MREIT and MREPT, enabled the measurement of conductivity-related properties within the body. MREIT assessed low-frequency conductivity by applying a lowfrequency external current, whereas MREPT captured high-frequency conductivity (at the Larmorfrequency) without applying an external current. In MREIT, the subject’s safety should be ensuredbecause electrical current is applied, particularly around sensitive areas, such as the brain, or in subjects with implanted electronic devices. Our previous studies have highlighted the potential ofconductivity indices as biomarkers for Alzheimer’s disease. MREPT is usually applied to humansrather than MREIT. MREPT holds promise as a noninvasive tool for characterizing tissue properties and understanding pathological conditions.

BACKGROUND: Bone growth factors, particularly bone morphogenic protein-2 (BMP-2), are required for effective treatment of significant bone loss. Despite the extensive development of bone substitutes, much remains to be desired for wider application in clinical settings. The currently available bone substitutes cannot sustain prolonged BMP-2 release and are inconvenient to use. In this study, we developed a ready-to-use bone substitute by sequential conjugation of BMP to a three-dimensional (3D) poly(L-lactide) (PLLA) scaffold using novel molecular adhesive materials that reduced the operation time and sustained prolonged BMP release. METHODS: A 3D PLLA scaffold was printed and BMP-2 was conjugated with alginate-catechol and collagen. PLLA scaffolds were conjugated with different concentrations of BMP-2 and evaluated for bone regeneration in vitro and in vivo using a mouse calvarial model. The BMP-2 release kinetics were analyzed using ELISA. Histological analysis and microCT image analysis were performed to evaluate new bone formation. RESULTS: The 3D structure of the PLLA scaffold had a pore size of 400 lm and grid thickness of 187–230 lm. BMP-2 was released in an initial burst, followed by a sustained release for 14 days. Released BMP-2 maintained osteoinductivity in vitro and in vivo. Micro-computed tomography and histological findings demonstrate that the PLLA scaffold conjugated with 2 lg/ml of BMP-2 induced optimal bone regeneration. CONCLUSION The 3D-printed PLLA scaffold conjugated with BMP-2 enhanced bone regeneration, demonstrating its potential as a novel bone substitute.

Purpose: This study reports on a series of patients with chronic lateral ankle instability that underwent the Broström procedure with suture tape augmentation and allowed early unrestricted weight-bearing in a simple stirrup brace. Materials and Methods: This retrospective study was conducted on 36 patients (22 males and 14 females of mean age 34 years [range 23~48 years]) with chronic lateral ankle instability treated using the Broström procedure using suture tape augmentation and inferior extensor retinaculum reinforcement with a fiber-wire connected to a SwiveLock screw inserted into the talus. When possible, patients started unrestricted weight-bearing in a stirrup brace from the third postoperative day. Demographics and functional outcomes, including American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot, visual analogue scale (VAS), and satisfaction scores, were recorded. In addition, varus stress radiographs obtained before and 24 months after surgery were compared. Patients were followed for a mean 29 months (range 25~40 months). Results: Mean AOFAS ankle-hindfoot scores increased from 51 points preoperatively to 92 points at final follow-up, and mean VAS decreased from 6.8 to 1.2 points. Mean patient satisfaction scores were 8.7 at 12 months and 9.6 at 24 months. Stress radiographs demonstrated that talar tilt decreased from a mean 18 degrees preoperatively to 7 degrees at 24 months. Conclusion Early unrestricted weight-bearing in a stirrup brace following the Broström procedure with suture tape augmentation is a successful protocol for treating chronic lateral ankle instability.

Purpose: We investigated whether response classification after total thyroidectomy and radioactive iodine (RAI) therapy could be affected by serum levels of recombinant human thyrotropin (rhTSH)-stimulated thyroglobulin (Tg) measured at different time points in a follow-up of patients with papillary thyroid carcinoma (PTC). Methods: A total of 147 PTC patients underwent serum Tg measurement for response assessment 6 to 24 months after the first RAI therapy. Serum Tg levels were measured at 24 h (D1Tg) and 48–72 h (D2-3Tg) after the 2nd injection of rhTSH. Responses were classified into three categories based on serum Tg corresponding to the excellent response (ER-Tg), indeterminate response (IR-Tg), and biochemical incomplete response (BIR-Tg). The distribution pattern of response classification based on serum Tg at different time points (D1Tg vs. D2-3Tg) was compared. Results: Serum D2-3Tg level was higher than D1Tg level (0.339 ng/mL vs. 0.239 ng/mL, P < 0.001). The distribution of response categories was not significantly different between D1Tg-based and D2-3Tg-based classification. However, 8 of 103 (7.8%) patients and 3 of 40 (7.5%) patients initially categorized as ER-Tg and IR-Tg based on D1Tg, respectively, were reclassified to IR-Tg and BIR-Tg based on D2-3Tg, respectively. The optimal cutoff values of D1Tg for the change of response categories were 0.557 ng/mL (from ER-Tg to IR-Tg) and 6.845 ng/mL (from IR-Tg to BIR-Tg). Conclusion D1Tg measurement was sufficient to assess the therapeutic response in most patients with low level of D1Tg. Nevertheless, D2-3Tg measurement was still necessary in the patients with D1Tg higher than a certain level as response classification based on D2-3Tg could change.

Purpose: We investigated the clinical role of F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography(PET-CT) in the identification of the primary site and the selection of the optimal biopsy site in patients with suspectedbone metastasis of unknown primary site. Methods: The patients with suspected bone metastasis who underwent PET-CT for evaluation of primary site were enrolled inthis study. The primary sites were identified by the histopathologic or imaging studies and were classified according to the FDGuptake positivity of the primary site. To evaluate the guiding capability of PET-CT in biopsy site selection, we statisticallyanalyzed whether the biopsy site could be affected according to the presence of extra-skeletal FDG uptake. Results: Among 74 enrolled patients, 51 patients had a metastatic bone disease. The primary site was identified in 48 of 51patients (94.1%). Forty-six patients were eligible to test the association of clinical choice of biopsy site with PET positivity ofextra-skeletal lesion. The extra-skeletal biopsies were done in 42 out of 43 patients with positive extra-skeletal uptake lesions.Bone biopsies were inevitably performed in the other three patients without extra-skeletal uptake lesions. The association cameout to be significant (Fisher’s exact test, P< 0.001). Conclusion F-18 FDG PET-CT significantly contributed not only to identify the primary site but also to suggest optimal biopsysites in patients with suspected bone metastasis.

PURPOSE: Thyroglobulin (Tg) may be released from damaged residual thyroid tissues after radioactive iodine (RAI) therapy in patients with differentiated thyroid carcinoma (DTC). We investigated whether altered levels of serum Tg after recombinant human thyrotropin (rhTSH)-aided RAI therapy could be a prognostic marker in patients with DTC.METHODS: We evaluated 68 patients who underwent RAI therapy after total thyroidectomy. Serum Tg levels were measured just before RAI administration (D0Tg) and 7 days after RAI therapy (D7Tg). Patients with a D0Tg level greater than 2.0 ng/mL were excluded to more precisely evaluate the injury effect of RAI in small remnant tissues. The ratioTg was defined as the D7Tg level divided by that on D0Tg. The therapeutic responses were classified as acceptable or non-acceptable. Finally, we investigated which clinicopathologic parameters were associated with therapeutic response.RESULTS: At the follow-up examination, an acceptable response was observed in 50 patients (73.5%). Univariate analysis revealed significant differences in N stage (P = 0.003) and ratioTg (acceptable vs. non-acceptable responses, 21.9 ± 33.6 vs. 3.8 ± 6.5; P = 0.006). In multivariate analysis, only ratioTg significantly predicted an acceptable response (odds ratio 1.104; 95% confidence interval 1.005–1.213; P = 0.040). A ratioTg above 3.5 predicted an acceptable response with a sensitivity of 66.0%, specificity of 83.3%, and accuracy of 70.6% (area under the curve = 0.718; P = 0.006).CONCLUSIONS: Altered levels of serum Tg after RAI therapy, calculated as the ratioTg (D7Tg/D0Tg), significantly predicted an acceptable response in patients with DTC.
Follow-Up Studies ; Humans ; Iodine ; Multivariate Analysis ; Sensitivity and Specificity ; Thyroglobulin ; Thyroid Gland ; Thyroid Neoplasms ; Thyroidectomy ; Thyrotropin