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To accurately interpret knee MRI, it is important not only to know the basic meniscal anatomy but also to distinguish it from that under pathological conditions. Thus, it would be helpful to know the normal meniscus variants (false positives) that could be mistaken for meniscal tears, and tears that could easily be missed and incorrectly diagnosed as normal (false negatives). False positives include synovial recesses, meniscal flounce, the relationship between the popliteus tendon and lateral meniscus, transverse ligament, the anterior root of the meniscus, and meniscofemoral ligament. False negatives include focal radial tears, flap tears, posterior root tears, meniscocapsular separation, and discoid meniscal tears. In this pictorial essay, we reviewed the imaging data obtained in the aforementioned cases.

To provide high-quality training to residents in a rapidly changing medical environment, it is very important to improve the annual training curriculum centered on competency and ensure that training hospitals maintain an environment suitable for training. The Korean Society of Radiology (KSR) has been steadily improving the training system and has suggested the improvement of the training system by strengthening the competency-based evaluation and faculty development. Currently, KSR was selected for the second annual training curriculum systematization construction project in July 2021, and developed entrustable professional activities, core competencies, and assessment guidelines required by the construction project. Therefore, the development process and assessment guidelines will be introduced to residents and the faculty.

Parosteal lipoma is a rare type of lipoma, the incidence being approximately 0.3% of all lipomas. Moreover, parosteal lipoma coexisting with osteochondroma is extremely rare. A few cases with coexistence of osteochondroma and parosteal lipoma have been reported and they were thought to be reactive changes of adjacent bone by parosteal lipoma. However, temporal relationship of these tumors could not be explained. Here, we report a case of parosteal lipoma associated with osteochondroma of the right ilium developed over 6 years, with follow-up radiographs.

Sesamoid bones and accessory ossicles are normal anatomic variants with varying morphological appearances and incidences. They are usually small osseous fragments with well-corticated margins located adjacent to the joint space and bone. Patients with sesamoid bones and accessory ossicles are usually asymptomatic and commonly encountered in clinical practice. These sesamoids and accessory bones are occasionally painful because of fractures, dislocations, degenerative changes, avascular necrosis, accessory bone infections, or abnormalities of the adjacent tissue, such as nerve entrapment, tenosynovitis, or soft tissue impingement. This article aimed to illustrate the imaging features of symptomatic sesamoids bones and accessory ossicles at various anatomic locations and describe their clinical features and radiological differential diagnosis.

Purpose To determine the reliability of edema grading of the psoas and paraspinal muscles on axial T2-weighted magnetic resonance (MR) image (T2WI) for the detection of lumbar transverse process (TP) fractures. Materials and Methods A retrospective review of lumbar spine MR images of 56 patients (mean age = 56.1 years, age range = 17–87 years, male:female = 28:28) was conducted by 2 radiologists. Based on the axial T2WI at the disc level, the paraspinal muscles were classified into 4 compartments and muscle edema (increased signal intensity on axial T2WI) grading performed for each quadrant. Results A total of 486 TPs (with fracture: 24, without fracture: 462) of 56 patients were evaluated. Muscle edema grade showed moderate correlation with the presence of TP fracture (ρ = 0.466). When the total score of muscle edema was 2.50, the receiver operating characteristic curve showed a sensitivity of 72.7% and a specificity of 90.7%. A higher edema grade had a significantly higher probability of concomitant TP fracture [any sided (total): odds ratio = 1.704 (95% confidence interval = 1.410–2.060)]. Conclusion Edema grading of the psoas and paraspinal muscles on axial T2WI of lumbar spine can be helpful in the detection of TP fracture.

Musculoskeletal (MSK) infections, such as osteomyelitis, infectious arthritis and spondylitis have variable radiographic findings depending on their underlying cause and clinical infection stage. Other disease entities, ranging from simple degenerative lesions to tumorous bone conditions, in which there is no evidence of infectious origin, can share similar radiographic findings. It is important to be aware, when interpreting radiographic features that are typically associated with MSK infections, that a non-infectious MSK disease may be mimicking the radiographic findings of infectious diseases.

Primary neurolymphoma (NL) involving the peripheral nervous system is a rare disease that involves the invasion of a nerve or nerve plexus by neoplastic lymphocytes. Although there have been a few reported clinical and pathological cases presenting as primary NL involving the peripheral nerve, the detailed radiological features of NL have not yet been discussed. In this report, we present a case of primary NL involving the tibial nerve and describe the detailed imaging findings on MRI including features used for differential diagnosis.

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) converts inactive cortisone to the active cortisol. 11β-HSD1 may be involved in the resolution of inflammation. In the present study, we investigate the anti-inflammatory effects of 2-(3-benzoyl)-4-hydroxy-1,1-dioxo-2H-1,2-benzothiazine-2-yl-1-phenylethanone (KR-66344), a selective 11β-HSD1 inhibitor, in lipopolysaccharide (LPS)-activated C57BL/6J mice and macrophages. LPS increased 11β-HSD1 activity and expression in macrophages, which was inhibited by KR-66344. In addition, KR-66344 increased survival rate in LPS treated C57BL/6J mice. HO-1 mRNA expression level was increased by KR-66344, and this effect was reversed by the HO competitive inhibitor, ZnPP, in macrophages. Moreover, ZnPP reversed the suppression of ROS formation and cell death induced by KR-66344. ZnPP also suppressed animal survival rate in LPS plus KR-66344 treated C57BL/6J mice. In the spleen of LPS-treated mice, KR-66344 prevented cell death via suppression of inflammation, followed by inhibition of ROS, iNOS and COX-2 expression. Furthermore, LPS increased NFκB-p65 and MAPK phosphorylation, and these effects were abolished by pretreatment with KR-66344. Taken together, KR-66344 protects against LPS-induced animal death and spleen injury by inhibition of inflammation via induction of HO-1 and inhibition of 11β-HSD1 activity. Thus, we concluded that the selective 11β-HSD1 inhibitor may provide a novel strategy in the prevention/treatment of inflammatory disorders in patients.

Various musculoskeletal findings incidentally detected on abdominopelvic computed tomography (CT) images have risen with the increasing use of abdominopelvic CT; however, it is not uncommon for radiologists to overlook the musculoskeletal system when they examine abdominopelvic CT images. Some musculoskeletal lesions may have more clinical significance than abdominopelvic lesions, although most lesions are of little to no significance. Many osseous lesions can be diagnosed using the bone window setting and reconstructed images. The purpose of this article was to review the wide variety of musculoskeletal lesions depicted on abdominopelvic CT images and to emphasize the use of the bone window setting.

Background: The purposes of the present study were (1) to create a magnetic resonance imaging (MRI)-based classification system for septic shoulder arthritis and to show the results of arthroscopic debridement based on the classification in eradicating the infection, and (2) to determine the distribution of the Gächter stages, which are determined on the basis of arthroscopic findings only, in each grade of the novel classification system.Methods: The present study included 31 patients who underwent arthroscopic debridement for the treatment of acute septic arthritis of the shoulder between January 2001 and December 2015. The mean duration of follow-up was 2.3 years. The included patients were assessed with use of a novel classification system based on preoperative radiographic and MRI findings. MRI findings were classified as Grade I (only synovitis or joint effusion), Grade II (marrow edema in the bare area of the humeral head), Grade III (cartilaginous erosion), Grade IV (osseous erosion), and Grade V (osseous erosion on MRI also observed on radiographs). No changes on radiographs were observed in Grades I to IV. The intraclass correlation coefficients (ICCs) for interobserver and intraobserver reliability were calculated.Results: The overall reinfection rate was 54.8% (17 of 31). Among patients with Grade-I, II, III, IV, and V involvement, the reinfection rates were 0 of 4, 1 of 6, 2 of 4, 9 of 12, and 5 of 5, respectively. A diverse distribution of Gächter stages were found in each grade of the novel classification system, with the exception of Grade V. The ICCs for interobserver and intraobserver reliability were 0.81 and 0.80 for the novel classification system. The ICCs for interobserver and intraobserver reliability were 0.75 and 0.78 for Gächter stages.Conclusions: This novel classification system for the grading of acute shoulder infections on the basis of radiographs and MRI allows preoperative grading of septic arthritis to be performed objectively. Patients who were classified as Grade III or higher in the novel classification system had higher reinfection rates than those who were classified as Grade I or II and required more aggressive treatment to eradicate the infection. [ABSTRACT FROM AUTHOR]

A rapid diagnostic test (RDT) kit was developed to detect non-structural protein 1 (NS1) of yellow fever virus (YFV) using monoclonal antibody. NS1 protein was purified from the cultured YFV and used to immunize mice. Monoclonal antibody to NS1 was selected and conjugated with colloidal gold to produce the YFV NS1 RDT kit. The YFV RDTs were evaluated for sensitivity and specificity using positive and negative samples of monkeys from Brazil and negative human blood samples from Korea. Among monoclonal antibodies, clones 3A11 and 3B7 proved most sensitive, and used for YFV RDT kit. Diagnostic accuracy of YFV RDT was fairly high; Sensitivity was 0.0% and specificity was 100% against Dengue viruses type 2 and 3, Zika, Chikungunya and Mayaro viruses. This YFV RDT kit could be employed as a test of choice for point-of-care diagnosis and large scale surveys of YFV infection under clinical or field conditions in endemic areas and on the globe. [ABSTRACT FROM AUTHOR]

Background: The diagnosis of clinically important instability following isolated supination-external rotation (SER) distal fibular fractures is a challenge. The purpose of this study was to investigate the accuracy of clinical findings including medial tenderness, swelling, and ecchymosis, combined with the gravity stress test and magnetic resonance imaging (MRI), in the assessment of ankle mortise stability in association with isolated SER-type lateral malleolar fractures. The external rotation (ER) stress test was used as the reference with which the methods of assessment were compared.Methods: Thirty-seven patients were enrolled prospectively. Using the ER stress test as a reference, we evaluated the sensitivity, specificity, likelihood ratio (LR), and post-test probability of instability when using clinical examination, the gravity stress test, and MRI for diagnosing ankle mortise instability after an isolated SER lateral malleolar fracture.Results: The positive LR for clinical findings ranged from 1.45 to 2.54, and the negative LR ranged from 0.25 to 0.70, shifting the pre-test probability to a rarely important degree. In contrast, the positive LR for the gravity stress test was 5.71 with a 95% confidence interval (CI) of 1.52 to 21.48, a moderate shift from the pre-test probability, and the negative LR was 0.33 (95% CI = 0.16 to 0.66), indicating a small shift. In cases with a deep deltoid ligament disruption identified on MRI, the positive LR was 3.05 (95% CI = 1.03 to 9.02) and the negative LR was 0.53 (95% CI = 0.31 to 0.91), demonstrating a small but sometimes important shift.Conclusions: The gravity stress test is a reliable method for diagnosing ankle mortise instability in patients with an isolated SER lateral malleolar fracture. Nevertheless, this test alone would not qualify as a replacement for the ER stress test. However, when the gravity stress test result is consistent with the clinical or MRI findings, its diagnostic value is almost equivalent to that of the ER stress test.Level Of Evidence: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Primary bone lymphoma (PBL) is an uncommon type of extranodal lymphoma involvement. An anaplastic large-cell lymphoma (ALCL) is an extremely rare type of PBL, and it remains unclear whether ALCLs that primarily involve the bone exhibit favourable or unfavourable biological behaviour, and whether they are similar to ALCLs in general, or not. We reported a case of ALKpositive ALCL with primary bone involvement, and reviewed the clinicopathological features of 22 previously reported cases. An ALCL with primary bone involvement mostly affects younger patients with a preponderant towards the involvement of axial-bone. The prognosis of an ALCL that primarily involves bone is unfavourable, compared with PBL generally. The ALK-positive ALCLs in PBLs had less decedents than the ALK-negative ALCLs with a statistical non-significance (p=0.198). [ABSTRACT FROM AUTHOR]

The R47H coding variant of the triggering receptor expressed on myeloid cells-2 (TREM2) increases the risk of Alzheimer's disease (AD) similar to apolipoprotein E4. TREM2 R47H has recently been shown to have impaired binding to damage-associated lipid or apolipoprotein ligands. However, it is not known how this R47H variant affects the biochemical characteristics of TREM2 and alters the pathogenesis of AD. We previously reported that TREM2-R47H has a slightly different glycosylation pattern from wild-type. A more detailed characterization in our present study confirms that TREM2 R47H has an altered glycosylation pattern and reduced stability. TREM2 R47H shows different glycosylation profiles from analysis using monensin or kifunensine treatment which were confirmed by mass spectrometry. The solubility of TREM2 R47H and its cleaved products such as intracellular domain (ICD) is also decreased, increasing its proteasomal and lysosomal degradation. The different biochemical characteristics of TREM2 R47H, including glycosylation, solubility and processing, may offer insights into a future therapeutic strategy for AD. [ABSTRACT FROM AUTHOR]

Amyloidosis is a disease characterized by the deposition of non-soluble fibrous protein in multiple tissues with a number of possible causes. This protein deposition can occur in any tissue, yet is most commonly seen in kidneys, heart, and gastrointestinal tracts. However, invasion to bone tissues is not often reported. The deposition of amyloid proteins in bone tissues may result in joint pain and pathological fractures; it is important to elucidate the causes and detect early to determine prognosis and treat optimally. In the present case report, with relevant literature review, the authors report a case of total hip arthroplasty in an amyloidosis patient. [ABSTRACT FROM AUTHOR]

Background. The optimal duration of antibiotic treatment for hematogenous vertebral osteomyelitis (HVO) should be based on the patient's risk of recurrence, but it is not well established. Methods. A retrospective review was conducted to evaluate the optimal duration of antibiotic treatment in patients with HVO at low and high risk of recurrence. Patients with at least 1 independent baseline risk factor for recurrence, determined by multivariable analysis, were considered as high risk and those with no risk factor as low risk. Results. A total of 314 patients withmicrobiologically diagnosed HVO were evaluable for recurrence. In multivariable analysis, methicillin- resistant Staphylococcus aureus infection (adjusted odds ratio [aOR], 2.61; 95% confidence interval [CI], 1.16–5.87), undrained paravertebral/ psoas abscesses (aOR, 4.09; 95% CI, 1.82–9.19), and end-stage renal disease (aOR, 6.58; 95% CI, 1.63–26.54) were independent baseline risk factors for recurrence. Therefore, 191 (60.8%) patients were classified as low risk and 123 (39.2%) as high risk. Among highrisk patients, there was a significant decreasing trend for recurrence according to total duration of antibiotic therapy: 34.8% (4–6 weeks [28–41 days]), 29.6% (6–8 weeks [42–55 days]), and 9.6% (≥8 weeks [≥56 days]) (P = .002). For low-risk patients, this association was still significant but the recurrence rates were much lower: 12.0% (4–6 weeks), 6.3% (6–8 weeks), and 2.2% (≥8 weeks) (P = .02). Conclusions. Antibiotic therapy of prolonged duration (≥8 weeks) should be given to patients with HVO at high risk of recurrence. For low-risk patients, a shorter duration (6–8 weeks) of pathogen-directed antibiotic therapy may be sufficient. [ABSTRACT FROM AUTHOR]

Objective : To evaluate whether an early bone marrow edema pattern predicts vertebral deformity types and prognosis in osteoporotic vertebral compression fracture (OVCF). Methods : This retrospective study enrolled 64 patients with 75 acute OVCFs who underwent early MRI and followed up MRI. On early MRI, the low SI pattern of OVCF on T1WI were assessed and classified into 3 types (diffuse, globular or patchy, band-like). On followed up MRI, the vertebral deformity types (anterior wedge, biconcave, crush), degree of vertebral body height loss, incidence of vertebral osteonecrosis and spinal stenosis were assessed for each vertebral fracture types. Results : According to the early bone marrow edema pattern on T1WI, 26 vertebrae were type 1, 14 vertebrae were type 2 and 35 vertebrae were type 3. On followed up MRI, the crush-type vertebral deformity was most frequent among the type 1 OVCFs, the biconcave-type vertebral deformity was most frequent among the type 2 OVCFs and the anterior wedge-type vertebral deformity was most frequent among the type 3 OVCFs (p<0.001). In addition, type 1 early bone marrow edema pattern of OVCF on T1WI were associated with higher incidence of severe degree vertebral body height loss, vertebral osteonecrosis and spinal stenosis on the follow up MRI. Conclusion : Early bone marrow edema pattern of OVCF on T1WI, significant correlated with vertebral deformity types on the follow up MRI. The severe degree of vertebral height loss, vertebral osteonecrosis, and spinal stenosis were more frequent in patients with diffuse low SI pattern. [ABSTRACT FROM AUTHOR]

We describe a case of an epiphyseal hemangioma in the humeral head of a 20-year-old man. On plain radiographs, the lesion showed no gross abnormality. The computed tomography images demonstrated the presence of an irregular and lobulating osteolytic lesion with a peripheral sclerotic rim and focal cortical defects. The magnetic resonance images showed an ill-defined low signal intensity on T1-weighted images and mixed low and high signal intensities on T2-weighted images. Additionally, ill-defined marrow enhancement with inner low signal lines was noted in this lesion. The patient was treated with curettage and a bone chip graft. The present case is instructive in the differential diagnosis of epiphyseal bone tumors; furthermore, the possibility of an intraosseous hemangioma should also be considered. [ABSTRACT FROM AUTHOR]

Background. Patients with hematogenous vertebral osteomyelitis (HVO) occasionally require instrumentation for spinal stabilization. However, placing instrumentation in the setting of spinal infection raises concerns about recurrent infection due to bacteria adhering to the foreign material. In this study, we evaluated the therapeutic outcomes of patients with HVO who underwent instrumented surgery. Methods. We conducted a retrospective chart review of adult patients with microbiologically diagnosed HVO who underwent surgical intervention in 5 tertiary care hospitals over an 8-year period. Results. A total of 153 patients with HVO underwent surgical management for their infections. Of these 153 patients, 94 (61.4%) underwent surgical debridement alone (noninstrumented surgery) and 59 (38.6%) underwent surgical debridement and instrumentation (instrumented surgery). The median durations of antibiotic therapy were 66 and 80 days for the noninstrumentation and instrumentation groups, respectively (P = .22). Clinical outcomes were similar between the groups, including rates of infection-related death (2.1% vs 0%; P = .52), primary failure (1.1% vs 5.1%; P = .30), and recurrence (4.8% vs 6.8%; P = .72). Among the instrumentation group, there was a significant decreasing trend for recurrence according to total duration of antibiotic therapy: 22.2% (4-6 weeks), 9.1% (6-8 weeks), and 2.6% (⩾8 weeks; P = .04). Duration of pre-instrumentation antibiotic therapy and single-stage operation (vs 2-stage operation) were not risk factors for recurrence. Conclusions. Spinal instrumentation in patients with HVO may be safe with pathogen-directed prolonged antibiotic therapy and should not be abandoned or delayed solely because of the risk of recurrence. [ABSTRACT FROM AUTHOR]

Epiphyseal involvement of a simple bone cyst (SBC) is rare. Furthermore, its pathological variant is even more uncommon. Herein, we report a case of a 22-year-old woman with an SBC containing unusual mesenchymal tissue proliferation with epiphyseal involvement in the proximal fibula. Magnetic resonance imaging showed a cystic lesion that involved the entire epiphysis as well as some soft tissue components. Hence, our initial differential diagnosis did not include SBC. However, pathology confirmed a SBC. Thus, SBC should be considered in the diagnosis of cystic lesions despite the atypical imaging findings. [ABSTRACT FROM AUTHOR]

Selective inhibitors of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) haveconsiderable potential as treatment for osteoporosis as well as metabolic syndrome including type 2 diabetes mellitus. Here, we investigated the anti-diabetic, anti-adipogenic, and antiosteoporotic activity of KR-67500, as a novel selective 11β-HSD1 inhibitor. Cellular 11β-HSD1 activitywas tested based on a homogeneous time-resolved fluorescence method. Oral glucose tolerance test (OGTT) and insulin tolerance test (ITT) levels were measured in diet-induced obese (DIO)-C57BL/6 mice administered KR-67500 (50 mg/kg per day, p.o.) for 28 days and, additionally, its anti-diabetic effectwas evaluated byOGTTand ITT. The in vitro anti-adipogenic effect of KR-67500was determined byOil RedOStaining. The in vitro anti-osteoporotic activity of KR-67500 was evaluated using bone morphogenetic protein 2 (BMP2)-induced osteoblast differentiation and receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation model systems. KR-67500 improved the in vivo glucose tolerance and insulin sensitivity in DIO-C57BL/6mice. KR-67500 suppressed cortisone-induced differentiation of 3T3- L1 cells into adipocytes. KR-67500 enhanced BMP2-induced osteoblastogenesis in C2C12 cells and inhibited RANKL-induced osteoclastogenesis in mouse bone marrow-derived macrophages. KR-67500, a newselective 11β-HSD1 inhibitor, may provide a newtherapeuticwindow in the prevention and/or treatment of type 2 diabetes, obesity, and/or osteoporosis. [ABSTRACT FROM AUTHOR]

The purpose was to assess the significance of herniation pits in the femoral neck for radiographic diagnosis of femoroacetabular impingement (FAI). Eighty hips in 62 patients (bilateral in 18) with neutral pelvic orientation were enrolled. Herniation pits were diagnosed when they were located at the anterosuperior femoral neck, close to the physis, and with a diameter of >3 mm. The five radiographic signs of FAI were used: lateral center edge angle (LCE) >39°, acetabular index (AI) ≤0, extrusion index (EI) <25%, acetabular retroversion, and pistol-grip deformity. Patients with radiographs suggesting FAI were retrospectively correlated with their clinical symptoms. Positive radiographic signs were observed in 7 hips with LCE, 7 with AI, and 80 with EI criteria. Only 3 hips out of 80 (3.8%) showed all of the signs. The acetabular retroversion and pistol-grip deformity were seen in 12/80 and 3/80 hips, respectively. The total number of hips that met radiographic criteria for FAI, including pincer type and cam type, was 18 (23%). However, none of these hips were clinically diagnosed with FAI. All symptomatic hips (11/80) presented only with nonspecific pain, and 2 hips out of 11 showed radiographic signs of FAI. The low frequency of positive radiographic signs suggesting FAI with related symptoms among patients with herniation pits suggests that herniation pits have limited significance in the diagnosis of FAI. Therefore it can be concluded that an incidental finding of herniation pits does not necessarily imply a correlation with FAI. [ABSTRACT FROM AUTHOR]

ObjectiveTo describe the CT findings of focal osteolysis following total hip replacement (THR).Design and patientsCT imaging features of 30 THRs with focal osteolysis visualized on follow-up radiographs and undertaken revision surgery were reviewed. On CT scans, the shape and anatomic location of osteolytic lesions was recorded, as well as their size and number. The presence of cortical disruption or expansion, liner wear, metallosis, and heterotopic ossification was also noted. In each case, surgical and histologic findings were correlated with imaging features.ResultsFocal osteolysis was common in the superior part of acetabular and femoral components. CT features of focal osteolysis were multiple, expansile, oval, or round radiolucencies, which were conglomerated into multilobular shape. The cortex adjacent to the osteolytic lesions revealed irregular thinning and discontinuity (29/30, 97%) accompanied by a few tiny fragments. Liner wear was common (27/30, 90%), and metallosis was frequent (8/30, 26.7%). Pathologic results were foreign body reaction in 20 patients, chronic inflammation in eight, and fibrosis in two.ConclusionCT appearances of focal osteolysis following THR are multilobulated lucent areas with expansile periosteal reaction and cortical abnormalities, mimicking infection or tumor. We consider that CT is useful for the prediction and assessment of the nature and extent of focal osteolysis. [ABSTRACT FROM AUTHOR]

Parosteal osteoma arising from long tubular bone is an extremely rare bone tumor and should be distinguished from parosteal osteosarcoma, whereas osteochondroma is a common benign bone tumor showing an outgrowth of medullary and cortical bone with a cartilaginous cap. This report describes simultaneously detected parosteal osteoma and osteochondroma arising from the distal femur in a single patient. [ABSTRACT FROM AUTHOR]