Fukushima Daiichi Nuclear Power Plant Accident: Understanding Formation Mechanism of Radioactive Particles through Sr and Pu Quantities.

The Fukushima Daiichi Nuclear Power Plant accident released considerable radionuclides into the environment. Radioactive particles, composed mainly of SiO2, emerged as distinctive features, revealing insights into the accident's dynamics. While studies extensively focused on high-volatile radionuclides like Cs, investigations into low-volatile nuclides such as 90Sr and Pu remain limited. Understanding their abundance in radioactive particles is crucial for deciphering the accident's details, including reactor temperatures and injection processes. Here, we aimed to determine 90Sr and Pu amounts in radioactive particles and provide essential data for understanding the formation processes and conditions within the reactor during the accident. We employed radiochemical analysis on nine radioactive particles and determined the amounts of 90Sr and Pu in these particles. 90Sr and Pu quantification in radioactive particles showed that the 90Sr/137Cs radioactivity ratio (corrected to March 11, 2011) aligned with core temperature expectations. However, the 239+240Pu/137Cs activity ratio indicated nonvolatile Pu introduction, possibly through fuel fragments. Analyzing 90Sr and Pu enhances our understanding of the Fukushima Daiichi accident. Deviations in 239+240Pu/137Cs activity ratios underscore nonvolatile processes, emphasizing the accident's complexity. Future research should expand this data set for a more comprehensive understanding of the accident's nuances.

Refined scan protocol for the evaluation of pulmonary perfusion standardized image quality and reduced radiation dose in dynamic chest radiography.

PURPOSE: Dynamic chest radiography (DCR) is a novel imaging technique used to noninvasively evaluate pulmonary perfusion. However, the standard DCR protocol, which is roughly adapted to the patient's body size, occasionally causes over- or underexposure, which could influence clinical evaluation. Therefore, we proposed a refined protocol by increasing the number of patient body mass index (BMI) categories from three to seven groups and verified its usefulness by comparing the image sensitivity indicators (S-values) and entrance surface doses (ESDs) of the conventional protocol with those of our refined protocol. METHODS: This retrospective observational study included 388 datasets (standing position, 224; supine position, 164) for the conventional protocol (December 2019-April 2021) and 336 datasets (standing position, 233; supine position, 103) for the refined protocol (June-November 2021). The conventional protocol (BMI-3 protocol) divided the patients into three BMI groups (BMI < 17, 17≤BMI < 25, and BMI ≥ 25 kg/m2 ), whereas the refined protocol (BMI-7 protocol) divided the patients into seven BMI groups (BMI < 17, 17 ≤ BMI < 20, 20 ≤ BMI < 23, 23 ≤ BMI < 26, 26 ≤ BMI < 29, 29 ≤ BMI < 32, and BMI ≥ 32 kg/m2 ). The coefficients of variation (CVs) for the S-values and ESDs acquired using the two protocols were compared. RESULTS: The CVs of the S-values in the BMI-7 protocol group were significantly lower than those in the BMI-3 protocol group for the standing (28.8% vs. 16.7%; p < 0.01) and supine (24.5% vs. 17.7%; p < 0.01) positions. The ESDs of patients scanned using the BMI-7 protocol were significantly lower than those scanned using the BMI-3 protocol in the standing (1.3 vs. 1.1 mGy; p < 0.01) and supine positions (2.5 vs. 1.6 mGy; p < 0.01), although the mean BMI of the two groups were similar. CONCLUSION: We introduced the BMI-7 protocol and demonstrated its standardized image quality and reduced radiation exposure in patients undergoing DCR.

Efficacy of Dynamic Chest Radiography for Chronic Thromboembolic Pulmonary Hypertension.

Background While current guidelines require lung ventilation-perfusion (V/Q) scanning as the first step to diagnose chronic pulmonary embolism in pulmonary hypertension (PH), its use may be limited by low availability and/or exposure to ionizing radiation. Purpose To compare the performance of dynamic chest radiography (DCR) and lung V/Q scanning for detection of chronic thromboembolic PH (CTEPH). Materials and Methods Patients with PH who underwent DCR and V/Q scanning in the supine position from December 2019 to July 2021 were retrospectively screened. The diagnosis of CTEPH was confirmed with right heart catheterization and invasive pulmonary angiography. Observer tests were conducted to evaluate the diagnostic accuracy of DCR and V/Q scanning. The lungs were divided into six areas (upper, middle, and lower for both) in the anteroposterior image, and the number of lung areas with thromboembolic perfusion defects was scored. Diagnostic performance was compared between DCR and V/Q scanning using the area under the receiver operating characteristic curve. Agreement between the interpretation of DCR and that of V/Q scanning was assessed using the Cohen kappa coefficient and percent agreement. Results A total of 50 patients with PH were analyzed: 29 with CTEPH (mean age, 64 years ± 15 [SD]; 19 women) and 21 without CTEPH (mean age, 61 years ± 22; 14 women). The sensitivity, specificity, and accuracy of DCR were 97%, 86%, and 92%, respectively, and those of V/Q scanning were 100%, 86%, and 94%, respectively. Areas under the receiver operating characteristic curve for DCR and V/Q scanning were 0.92 (95% CI: 0.79, 0.97) and 0.93 (95% CI: 0.78, 0.98). Agreement between the consensus interpretation of DCR and that of V/Q scanning was substantial (κ = 0.79 [95% CI: 0.61, 0.96], percent agreement = 0.9 [95% CI: 0.79, 0.95]). Conclusion Dynamic chest radiography had similar efficacy to ventilation-perfusion scanning in the detection of chronic thromboembolic pulmonary hypertension. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Wandtke and Koproth-Joslin in this issue.

Establishment and validation of an electron inelastic mean free path database for narrow bandgap inorganic compounds with a machine learning approach.

Narrow bandgap inorganic compounds are extremely important in many areas of physics. However, their basic parameter database for surface analysis is incomplete. Electron inelastic mean free paths (IMFPs) are important parameters in surface analysis methods, such as electron spectroscopy and electron microscopy. Our previous research has presented a machine learning (ML) method to describe and predict IMFPs from calculated IMFPs for 41 elemental solids. This paper extends the use of the same machine learning method to 42 inorganic compounds based on the experience in predicting elemental electron IMFPs. The in-depth discussion extends to including material dependence discussion and parameter value selections. After robust validation of the ML method, we have produced an extensive IMFP database for 12 039 narrow bandgap inorganic compounds. Our findings suggest that ML is very efficient and powerful for IMFP description and database completion for various materials and has many advantages, including stability and convenience, over traditional methods.

Assessment of bone health in patients with prostate cancer using cancer staging computed tomography.

PURPOSE: To evaluate the utility of vertebral Hounsfield unit (HU) values from computed tomography (CT) in cancer staging as a supplementary screening tool for bone health among prostate cancer (PCa) patients. METHODS: T-scores of bone mineral density (BMD) in each lumbar vertebra (L1-L4) and hip for newly diagnosed PCa patients (N = 139) were measured using dual-energy X-ray absorptiometry (DXA). The degenerative changes in each lumbar vertebra were assessed, and the HU values of trabecular bone in axial CT images of each vertebral body (vertebral CT-HU value) were measured using staging CT. RESULTS: 556 vertebrae were analyzed. 326 of 556 (59%) lumbar vertebrae had degenerative changes. The vertebral CT-HU value was positively correlated with the lumbar BMD T-score, with higher correlation coefficients observed in vertebrae without degenerative changes (r = 0.655, N = 230) when compared to vertebrae with degenerative changes (r = 0.575, N = 326). The thresholds matching BMD T-scores of - 2.0 and - 1.5 set by cancer treatment-induced bone loss guidelines were 95 HU and 105 HU, respectively. Based on the intervention threshold (lumbar BMD T-score < - 1.5), 15.1% of PCa patients required osteoporosis treatment; and, this value increased to 30.9% when L1-L4 CT-HU thresholds that corresponded to BMD T-score < - 1.5 were used. CONCLUSION: Lumbar BMD values from DXA may not reflect true bone health in PCa patients who often have lumbar degenerative diseases. Thresholds based on the vertebral CT-HU value can be used as a supplementary method to identify PCa patients who need anti-osteoporosis drugs.

Low serum albumin concentration is associated with increased risk of osteoporosis in postmenopausal patients with rheumatoid arthritis.

BACKGROUND: The risk of osteoporosis in patients with rheumatoid arthritis (RA) is frequently overlooked, and investigating a simple indicator in routine care may be beneficial to motivate osteoporosis examination. The aim of this retrospective, case-controlled study was to identify the correlation between serum albumin concentrations and the prevalence of osteoporosis in postmenopausal patients with RA. METHODS: This study enrolled 197 patients who underwent dual-energy X-ray absorptiometry of lumbar spine (LS) and proximal femur without osteoporosis treatment [mean age, 67.5 years; disease duration, 12.8 years; Disease Activity Score assessing 28 joints with C-reactive protein, 2.0; prednisolone dose, 4.9 mg/day (usage, 42.6%); and LS T-score, -1.9]. Patients were classified into 2 groups: osteoporosis, defined as ≥ 1 part bone mineral density T-score ≤ -2.5 or history of fragility fracture of the vertebra or proximal femur (121 patients), and non-osteoporosis (76 patients). Groups were then matched by propensity score using clinical backgrounds affecting bone metabolism. RESULTS: In non-matched model, serum albumin concentration was significantly associated with osteoporosis-related factors such as aging, inflammation, physical disability, and glucocorticoid dose. Multivariate logistic regression revealed that serum albumin concentration was independently and significantly associated with osteoporosis risk (odds ratio = 0.22, 95% confidence interval = 0.08, 0.61, p = 0.0033). After propensity score matching, 57 patients for each group showed that in addition to the LS and femoral neck T-scores (p < 0.001), serum albumin concentrations (p = 0.01) remained lower in the osteoporosis group compared to non-osteoporosis group. Receiver operating characteristic curve analysis in non-matched model revealed that when cut-off value of serum albumin concentration for indicating osteoporosis was set at 4.2 g/dl, the area under the curve was 0.69, sensitivity 0.74, and specificity 0.58. CONCLUSIONS: Low serum albumin concentration was significantly and independently associated with the prevalence of osteoporosis, which may be considered as one of the osteoporosis-related factors in postmenopausal patients with RA.

Impact of surgical resection on survival in patients with metastatic soft tissue sarcoma and comparison between synchronous and metachronous metastases.

BACKGROUND: The role of local surgery in patients with metastatic soft tissue sarcoma (STS) remains unknown. The study aims to assess the clinical outcomes and impact of surgical resection on survival in patients with metastatic STS and elucidate the survival differences between synchronous and metachronous metastatic groups. METHODS: Among the 272 patients with STS treated between 2000 and 2018, 84 with synchronous or metachronous metastasis were included. Associations between overall survival and primary tumor resection and metastasectomy were assessed using multivariate Cox regression analyses to adjust for baseline differences between surgically and non-surgically treated patients. Propensity score matching was applied to compare synchronous and metachronous metastasis. RESULTS: Among the 84 patients included, 69 (82%) and 41 (49%) underwent primary tumor resection and metastasectomy, respectively. The 2- and 5-year overall survivals of all patients after first detection of metastasis were 51.1% and 24.4%, respectively. Multivariate analysis showed that size <8 cm, grade <3, and number of metastases <4 were associated with longer overall survival. After adjusting for baseline demographic and tumor characteristics, primary tumor resection and metastasectomy still had favorable effects on survival. Tumor subtypes, grade, and number of metastases differed significantly between synchronous and metachronous groups. However, after adjusting for these valuables, both groups exhibited comparable survival. CONCLUSIONS: Approximately one fourth of the patients with metastatic STS survived for >5 years. Our results showed that surgical resection of primary tumors or metastatic lesions had favorable impact on survival even after adjusting for patient backgrounds, with comparable survival observed between those with synchronous and metachronous metastases.

Effects of iguratimod on glucocorticoid-induced disorder of bone metabolism in vitro.

INTRODUCTION: Glucocorticoids are widely used to treat various diseases including rheumatoid arthritis (RA); however, one of the most frequent and severe adverse effects is glucocorticoid-induced osteoporosis (GIOP). Iguratimod (IGU) is a novel conventional synthetic disease-modifying anti-rheumatic drug developed in Japan. The aim of this study is to investigate the effects of IGU on glucocorticoid-induced disorder of bone metabolism in vitro. MATERIALS AND METHODS: In osteoclastogenesis of mouse bone marrow-derived cells, tartrate-resistant acid phosphatase staining, resorption pit assay, western blotting, real-time polymerase chain reaction (PCR), and mRNA sequencing were performed. In osteoblastogenesis of MC3T3-E1 cells, alkaline phosphatase (ALP) staining and activity, alizarin red staining, and mRNA sequencing were performed, and real-time PCR and western blotting were conducted in MC3T3-E1 cells and murine osteocyte-like cell line MLO-Y4 cells. RESULTS: IGU significantly suppressed a dexamethasone-induced increase in osteoclasts, differentiation, and bone resorption activity by inhibition of the receptor activator of the nuclear factor kappa-B (RANK)/tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6)/nuclear factor kappa-B (NFκB)-p52 pathway. In MC3T3-E1 cells, IGU significantly upregulated dexamethasone-induced downregulation of ALP activity, bone mineralization, and osteoblast-related gene and protein expression. In MLO-Y4 cells, IGU significantly upregulated dexamethasone-induced downregulation of the gene expression of ALP and osteocalcin, and also downregulated receptor activator of NFκB ligand (RANKL)/osteoprotegerin gene expression ratio without dexamethasone. CONCLUSION: These results suggest that IGU may improve glucocorticoid-induced disorder of bone metabolism and may exhibit positive effects against GIOP associated with RA.

Impact of mechanical stability on the progress of bone ongrowth on the frame surfaces of a titanium-coated PEEK cage and a 3D porous titanium alloy cage: in vivo analysis using CT color mapping.

PURPOSE: To determine the impact of mechanical stability on the progress of bone ongrowth on the frame surfaces of a titanium-coated polyether ether ketone (TCP) cage and a three-dimensional porous titanium alloy (PTA) cage following posterior lumbar interbody fusion (PLIF) until 1 year postoperatively. METHODS: A total of 59 patients who underwent one- or two-level PLIF for degenerative lumbar disorders since March 2015 were enrolled. Bone ongrowth of all cage frame surfaces (four surfaces per cage: TCP, 288 surfaces and PTA, 284 surfaces) was graded by 6-month and 1-year postoperative computed tomography color mapping (grade 0, 0‒25% of bone ongrowth; grade 1, 26‒50%; grade 2, 51‒75%; and grade 3, 76‒100%). RESULTS: Bone ongrowth (≥ grade 1) was observed on 58.0% and 69.0% of the surfaces of TCP and PTA cages 6 months postoperatively and on 63.5% and 75.0% of those 1 year postoperatively, respectively. In the TCP cages, bone ongrowth grade increased from 6 months to 1 year postoperatively only in the union segments (median, 1 [interquartile range, IQR, 0-2] to 1 [IQR, 0-3], p = 0.006). By contrast, in the PTA cages, it increased at 6 months postoperatively in the union (1 [IQR, 1-2] to 2 [IQR, 1-3], p = 0.003) and non-union (0.5 [IQR, 0-2] to 1 [IQR, 0-2.75], p = 0.002) segments. CONCLUSION: Early postoperative mechanical stability has a positive impact on the progress of bone ongrowth on both the TCP and PTA cage frame surfaces after PLIF.

Different effects of the lateral meniscus complete radial tear on the load distribution and transmission functions depending on the tear site.

PURPOSE: To compare the effect of the lateral meniscus (LM) complete radial tear at different tear sites on the load distribution and transmission functions. METHODS: A compressive load of 300 N was applied to the intact porcine knees (n = 30) at 15°, 30°, 60°, 90°, and 120° of flexion. The LM complete radial tears were created at the middle portion (group M), the posterior portion (group P), or the posterior root (group R) (n = 10, each group), and the same loading procedure was followed. Finally, the recorded three-dimensional paths were reproduced on the LM-removed knees. The peak contact pressure (contact area) in the lateral compartment and the calculated in situ force of the LM under the principle of superposition were compared among the four groups (intact, group M, group P, and group R). RESULTS: At all the flexion angles, the peak contact pressure (contact area) was significantly higher (lower) after creating the LM complete radial tear as compared to that in the intact state (p < 0.01). At 120° of flexion, group R represented the highest peak contact pressure (lowest contact area), followed by group P and group M (p < 0.05). The results of the in situ force carried by the LM were similar to those of the tibiofemoral contact mechanics. CONCLUSION: The detrimental effect of the LM complete radial tear on the load distribution and transmission functions was greatest in the posterior root tear, followed by the posterior portion tear and the middle portion tear in the deep-flexed position. Complete radial tars of the meniscus, especially at the posterior root, should be repaired to restore the biomechanical function.

Factors related to length of hospital stay after two-stage corrective surgery for adult spinal deformity in elderly Japanese.

BACKGROUND: Postoperative recovery of activities of daily living after surgery in elderly patients often takes a longer time because of their frailty. However, it is unclear how long it takes for patients with adult spinal deformity (ASD) to recover their abilities to live their daily lives in their home after corrective fusion surgery. This study aimed to investigate the length of hospital stay required to perform activities of daily living (ADL) in patients undergoing two-stage corrective fusion surgery for ASD in our institution and to detect factors associated with the length of hospital stay. METHODS: Thirty-four consecutive female ASD patients (median age, 70 years) who underwent two-stage corrective fusion surgery (lateral lumbar interbody fusion at the first stage and posterior corrective fusion at the second stage) from T9 or T10 to the pelvis were included. The length of hospital stay from admission to return home was determined, and correlations between length of hospital stay and demographics, skeletal muscle mass, operative invasion and perioperative complications, and spino-pelvic alignment were investigated. RESULTS: The median length of hospital stay was 51 days, exceeding 100 days in 25% of cases. Age at surgery (ρ = 0.545, p = 0.001), estimated glomerular filtration rate (ρ = -0.603, p < 0.001), age-adjusted Charlson comorbidity index (ρ = 0.437, p = 0.01), and preoperative pelvic incidence (ρ = 0.356, p = 0.04) were correlated with length of hospital stay. Preoperative skeletal muscle mass, preoperative spinal imbalance, perioperative changes in spino-pelvic alignment, operative invasion, and perioperative complications were not correlated with length of hospital stay. CONCLUSIONS: After >50 days, ADL performance of each patient reached the extent required for daily living to return home after two-stage corrective fusion surgery for ASD. Factors related to length of hospital stay were age and indices related to frailty.

Effects of follow-on therapy after denosumab discontinuation in patients with postmenopausal osteoporosis.

OBJECTIVES: To clarify the effects of follow-on therapy after denosumab (DMAb) discontinuation. METHODS: In this retrospective, multicenter study, postmenopausal patients with osteoporosis who were previously treated by oral bisphosphonates (BP) (n = 26) or teriparatide (TPTD) (n = 27) were switched to DMAb (administered 2.6 times), and then discontinued. Patients (73.1 years, T-scores of the lumbar spine [LS] - 2.7 and femoral neck [FN] - 2.2) were switched to either (1) raloxifene (RAL) (n = 13) or BP [(2) weekly or monthly BP (wmBP) (n = 29) or (3) zoledronate (ZOL) (n = 11)], based on each physician's decision (mean interval after final DMAb administration was 7.2 months). Bone mineral density (BMD) at final DMAb administration were set as baseline. RESULTS: Changes in LS BMD at 1.5 years after final DMAb administration were -2.7% in the RAL, 0.7% in the wmBP, and 1.9% in the ZOL (p = .31 between groups), and in FN BMD were -3.8%, -0.8%, and 1.8%, respectively (p = .02 between the RAL and ZOL; p = .048 between the RAL and BP). Clinical vertebral fracture incidence during 1.5 years after final DMAb administration was 23.1% in the RAL, 3.4% in the wmBP, and 0.0% in the ZOL (p = .048 between the RAL and ZOL; p = .015 between the RAL and BP). No significant differences were observed in these parameters between the wmBP and ZOL. CONCLUSION: These results may contribute to the selection of adequate follow-on therapy after DMAb discontinuation, although further investigations are required.

Complication rate, functional outcomes, and risk factors associated with carbon ion radiotherapy for patients with unresectable pelvic bone sarcoma.

BACKGROUND: To the authors' knowledge, carbon ion radiotherapy (CIRT) is one of the few curative treatments for unresectable pelvic bone sarcoma. The current study investigated the complications, functional outcomes, and risk factors of CIRT. METHODS: Of 112 patients who were treated with CIRT for unresectable pelvic bone sarcoma, the authors enrolled 29 patients who were without local disease recurrence or distant metastasis. The mean follow-up was 93 months. Complications, functional outcomes, and quality of life scores were assessed. Risk factors were analyzed, including the dose-volume histogram of the femoral head. RESULTS: Femoral head necrosis occurred in approximately 37% of patients, pelvic fractures were reported in 48% of patients, and neurological deficits were noted in 52% of patients. Femoral head necrosis was found to be significantly more prevalent among patients with periacetabular tumors (P = .018). The dose-volume histogram of the femoral head indicated tolerable volume percentages of the femoral head to be <33% for 40 grays (relative biological effectiveness) and 16% for 60 grays ( relative biological effectiveness). The mean Musculoskeletal Tumor Society score and Toronto Extremity Salvage Score were 53% and 64%, respectively, and the mean EuroQol 5 dimensions questionnaire index was 0.587. Patients aged >50 years and those with periacetabular tumors were found to have significantly lower Toronto Extremity Salvage Scores. CONCLUSIONS: Femoral head necrosis, pelvic fracture, and nerve damage are common complications with the use of CIRT for pelvic bone sarcoma. To prevent femoral head necrosis, the radiation dose to the femoral head should be kept below the estimated tolerance curve presented in the current study. The functional outcome is nearly equivalent to that of surgery. CIRT may be a promising alternative to surgery for patients with unresectable pelvic bone sarcoma.

Extracorporeal shock wave therapy accelerates endochondral ossification and fracture healing in a rat femur delayed-union model.

Extracorporeal shock wave therapy (ESWT) has been demonstrated to accelerate bone healing; however, the mechanism underlying ESWT-induced bone regeneration has not been fully elucidated. This study aimed to examine the effects of ESWT and the process of fracture healing. A rat model of femur delayed-union was established by cauterizing the periosteum. ESWT treatment at the fracture site was performed 2 weeks after the operation and the site was radiographically and histologically evaluated at weeks 4, 6, and 8. The bone union rate and radiographic score of the ESWT group were significantly higher than those of the control group at 8 weeks. Histological evaluation revealed enhanced endochondral ossification at the fracture site. The effects of ESWT on ATDC5 cells were examined in vitro. ESWT promoted chondrogenic differentiation without inhibiting the proliferation of ATDC5 cells. ESWT may induce significant bone healing by promoting endochondral ossification at the fracture site.

Mycobacterium kansasii arthritis of the elbow in an immunocompetent patient with a suspected soft-tissue tumor.

Mycobacterium kansasii is one of the major non-tuberculous mycobacteria species that typically cause pulmonary diseases. M. kansasii is known to cause septic arthritis as an extrapulmonary disease in immunosuppressed patients or chronic skin disease. Herein, we present a case of M. kansasii arthritis involving the elbow of an immunocompetent patient, which was initially suspected to be a soft-tissue tumor. A 70-year-old man presented with a swollen left elbow that had progressed for 18 months with deteriorating arthralgia and limited range of motion. Magnetic resonance imaging revealed filling of the intra-articular space of the elbow and surrounding of the radial head with a soft tissue mass with mixed signal intensity. Initial incisional biopsy was performed via the lateral approach to the elbow joint, and pathological examination of the mass did not reveal any evidence of malignancy. One year after the first operation, arthroscopic surgery was performed to excise the mass following the recurrence of swelling and limited function of the elbow. Pathological examination of the resected synovium revealed epithelioid granulomas containing a multinucleated giant cell and inflammatory cell infiltration, characteristic of mycobacterial infection. M. kansasii was cultured after 2 weeks of incubation of the synovial sample. He experienced full resolution of the swelling and limited function following a combination of synovectomy and multidrug antimycobacterial treatment (rifampin 600 mg/day, clarithromycin 800 mg/day, and ethambutol 750 mg/day). This case highlights the need to consider this rare infection in the differential diagnosis of intra-articular soft tissue tumor-like lesions even in immunocompetent patients.

Resting-state Amplitude of Low-frequency Fluctuation is a Potentially Useful Prognostic Functional Biomarker in Cervical Myelopathy.

BACKGROUND: Cervical MRI is the standard diagnostic imaging technique for patients with cervical myelopathy. However, the utility of conventional cervical MRI as a predictive biomarker for surgical recovery remains unclear, partly because of the limited information obtained from this anatomically small area. Brain resting-state functional MRI (rs-fMRI) may help identify candidate predictive biomarkers. Two analytical methods that assess local spontaneous brain activity are widely used for rs-fMRI: functional connectivity between two brain regions and amplitude of low-frequency fluctuation (ALFF). In our previous analysis of functional connectivity, we discovered that brain functional connectivity may be a predictive biomarker for neurologic recovery in patients with cervical myelopathy; however, the functional connectivity analysis identified a correlation with only one clinical outcome (the 10-second test). To establish a comprehensive prediction measure, we need to explore other brain biomarkers that can predict recovery of other clinical outcomes in patients with cervical myelopathy. QUESTIONS/PURPOSES: We aimed to (1) elucidate preoperative ALFF alterations in patients with cervical myelopathy and how ALFF changes after surgery, with a focus on postoperative normalization and (2) establish a predictive model using preoperative ALFF by investigating the correlation between preoperative ALFF and postoperative clinical recovery in patients with cervical myelopathy. METHODS: Between August 2015 and June 2017, we treated 40 patients with cervical myelopathy. Thirty patients met our prespecified inclusion criteria, all were invited to participate, and 28 patients opted to do so (93%; 14 men and 14 women; mean age: 67 years). The 28 patients and 28 age- and sex-matched controls underwent rs-fMRI (twice for patients with cervical myelopathy: before and 6 months after cervical decompression surgery). We analyzed the same study population that was used in our earlier study investigating functional connectivity. Controls had none of the following abnormalities: neck or arm pain, visual or auditory disorders, cognitive disorder, structural brain disorder, a history of brain surgery, mental and neurologic disorders, and medications for the central nervous system. We performed ALFF comparisons between preoperative patients with cervical myelopathy and controls, analyzed postoperative ALFF changes in patients with cervical myelopathy, and performed a correlation analysis between preoperative ALFF and clinical recovery in these patients. Clinical outcomes in the cervical myelopathy group were assessed using the 10-second test, the Japanese Orthopaedic Association upper-extremity motor (JOA-UEM) score, JOA upper-extremity sensory score (JOA-UES), and Japanese Orthopaedic Association Cervical Myelopathy Evaluation Questionnaire for upper-extremity function (JOACMEQ-UEF) score before and 6 months after surgery, which is when we believe these scores generally reach a plateau. A total of 93% of those enrolled (26 of 28 patients) were analyzed both preoperatively and postoperatively; the other two were lost to follow-up. RESULTS: The cervical myelopathy group had an increase in ALFF in the bilateral primary sensorimotor cortices (right, cluster size = 850 voxels, t-value = 6.10; left, cluster size = 370 voxels, t-value = 4.84) and left visual cortex (cluster size = 556 voxels, t-value = 4.21) compared with the control group. The cervical myelopathy group had a decrease in ALFF in the bilateral posterior supramarginal gyrus (right, cluster size = 222 voxels, t-value = 5.09; left, cluster size = 436 voxels, t-value = 5.28). After surgery, the bilateral sensorimotor cortices (right, cluster size = 468 voxels, t-value = 6.74; left, cluster size = 167 voxels, t-value = 5.40) and left visual cortex (cluster size = 3748 voxels, t-value = 6.66) showed decreased ALFF compared with preoperative ALFF, indicating postoperative normalization of spontaneous brain activities in these regions. However, the bilateral posterior supramarginal gyrus did not show an increase in ALFF postoperatively, although ALFF in this region decreased preoperatively. Greater levels of ALFF at the left and right frontal pole and left pars opercularis of the inferior frontal gyrus before surgery in the cervical myelopathy group were correlated with larger improvements in the JOACMEQ-UEF score 6 months after surgery (r = 0.784; p < 0.001, r = 0.734; p < 0.001 and r = 0.770, respectively; p < 0.001). The prediction formula, based on preoperative ALFF values in the left frontal pole, was as follows: the predicted postoperative improvement in the JOACMEQ-UEF score = 34.6 × preoperative ALFF value - 7.0 (r = 0.614; p < 0.001). CONCLUSIONS: Our findings suggest that preoperative ALFF may be a biomarker for postoperative recovery in that it predicted postoperative JOACMEQ-UEF scores. To establish a comprehensive prediction measure for neurologic recovery in patients with cervical myelopathy, a multicenter study is underway. LEVEL OF EVIDENCE: Level II, diagnostic study.

Clinical outcomes of chondroblastoma treated using synthetic bone substitute: risk factors for developing radiographic joint degeneration.

BACKGROUND: Chondroblastoma (CB) is a rare locally aggressive bone tumor that commonly occurs in the epiphysis or apophysis of long bones. Although surgical treatment of CB carries potential risk for physeal or articular cartilage damage, risk factors for joint degeneration have not been well described. In addition, we have mainly used synthetic bone substitute (SBS) to fill the bone defect after intralesional curettage as treatment for CB. This study thus aimed to evaluate the incidence of and risk factors for adjacent-joint radiographic degeneration after SBS treatment for CB. METHODS: We retrospectively reviewed 48 patients treated for CB at our institutions between 1996 and 2017. Clinical data, radiographic images, treatments, and local recurrence were analyzed. RESULTS: We identified 40 patients [29 males and 11 females with a mean age of 19 years (range, 8-35 years)] who received SBS to fill the defect after curettage with a minimum follow-up of 1 year. The mean follow-up period was 71 months (range, 13-239 months). A total of 8 patients (20%) developed local recurrence. Radiographic analysis showed that 5 patients (16.7%) developed radiographic joint degeneration. Joint degeneration was significantly associated with the affected joint (p = 0.004). CONCLUSIONS: Curettage and SBS filling had been found to be a reasonable treatment method for CB, which commonly occurs in the epiphysis or apophysis. Radiographic joint degeneration was not uncommon after CB treatment, especially in the talus and proximal humerus.

A longitudinal tear in the medial meniscal body decreased the in situ meniscus force under an axial load.

PURPOSE: To clarify the effect of longitudinal tears of the medial meniscus on the in situ meniscus force and the tibiofemoral relationship under axial load. METHODS: Twenty-one intact porcine knees were mounted on a 6-degrees of freedom robotic system, and the force and three-dimensional path of the knee joints were recorded during three cycles under a 250-N axial load at 30°, 60°, 90° and 120° of knee flexion. They were divided into three groups of seven knees with longitudinal tears in the middle to the posterior segment of the medial meniscus based on the tear site: rim, outer one-third and inner one-third of the meniscal body. After creating tears, the same tests were performed. Finally, all paths were reproduced after total medial meniscectomy, and the in situ force of the medial meniscus was calculated based on the principle of superposition. RESULTS: With a longitudinal tear, the in situ force of the medial meniscus was significantly decreased at 60°, 90° and 120° of knee flexion, regardless of the tear site. The decrement was greater with a tear in the meniscal body than a tear in the rim. A longitudinal tear in the meniscal body caused a significantly greater tibial varus rotation than a tear in the rim at all flexion angles. CONCLUSION: Longitudinal tears significantly decreased the in situ force of the medial meniscus. Tears in the meniscal body caused a larger decrease of the in situ meniscus force and greater varus tibial rotation than tears in the rim.

Development of spectral decomposition based on Bayesian information criterion with estimation of confidence interval.

We develop an automatic peak fitting algorithm using the Bayesian information criterion (BIC) fitting method with confidence-interval estimation in spectral decomposition. First, spectral decomposition is carried out by adopting the Bayesian exchange Monte Carlo method for various artificial spectral data, and the confidence interval of fitting parameters is evaluated. From the results, an approximated model formula that expresses the confidence interval of parameters and the relationship between the peak-to-peak distance and the signal-to-noise ratio is derived. Next, for real spectral data, we compare the confidence interval of each peak parameter obtained using the Bayesian exchange Monte Carlo method with the confidence interval obtained from the BIC-fitting with the model selection function and the proposed approximated formula. We thus confirm that the parameter confidence intervals obtained using the two methods agree well. It is therefore possible to not only simply estimate the appropriate number of peaks by BIC-fitting but also obtain the confidence interval of fitting parameters.

Tibial tunnel enlargement after anatomic anterior cruciate ligament reconstruction with a bone-patellar tendon-bone graft. Part 2: Factors related to the tibial tunnel enlargement.

BACKGROUND: Factors related to tunnel enlargement after anterior cruciate ligament (ACL) reconstruction should be evaluated by multivariate analysis, because the phenomenon has multifactorial characteristics. The purpose of this study was to elucidate the factors related to the tibial tunnel enlargement rate after anatomic ACL reconstruction with a bone-patellar tendon-bone (BTB) graft using multivariate analysis. METHODS: Eighteen patients with unilateral ACL rupture were included. The anatomic rectangular-tunnel (ART) ACL reconstruction with a BTB autograft was performed. 3D CT models of the tibia, the tibial tunnel, and the bone plug at 3 weeks and 1 year after surgery were reconstructed and superimposed using a surface registration technique. The cross-sectional area (CSA) of the tibial tunnel perpendicular to the tunnel axis was evaluated at the aperture. The CSA was measured at 3 weeks and 1 year after surgery, and the tunnel enlargement rate at the aperture was calculated. Multiple linear regression analysis was performed to detect the significantly related factors to the tibial tunnel enlargement rate at the aperture among potential factors consisting of preoperative demographic factors and predisposing factors with the tibial tunnel. RESULTS: The tibial tunnel enlargement rate at the aperture was 21.9 ± 14.1% (mean ± standard deviation). Multiple linear regression analysis detected the tendon length inside the tunnel as a significantly independent factor related to the tibial tunnel enlargement rate at the aperture (standardized ß = 0.726, P = 0.008). There was no significant relationship between the tibial tunnel enlargement rate at the aperture and postoperative side-to-side difference (SSD) of the anterior knee laxity or Tegner activity level scale under single linear regression analysis. CONCLUSION: The greater tendon length inside the tunnel was independently related to the higher tibial tunnel enlargement rate at the aperture 1-year after anatomic ACL reconstruction with a BTB graft under multiple linear regression analysis.