Training intensity of robot-assisted gait training in children with cerebral palsy.

AIM: We compared three different intensities of robot-assisted gait training (RAGT) for achieving favourable outcomes in children with cerebral palsy (CP). METHOD: This study was conducted using a randomized controlled, single-blind design. Thirty children (19 males and 11 females; mean age 6 years 1 month, SD 2 years) with CP classified in Gross Motor Function Classification System levels II and III were assigned to three different RAGT intensity groups: high-intensity (fastest walking speed and lowest body weight support [BWS]), low-intensity (slowest speed and highest BWS), and comfortable intensity (intermediate speed and intermediate BWS). The RAGT intervention was performed three times a week for 6 weeks. Outcome measures included the 88-item Gross Motor Function Measure, stability index, spatiotemporal parameters of gait analysis, paediatric functional independence measure, and the Canadian Occupational Performance Measure. RESULTS: The 88-item Gross Motor Function Measure was significantly improved after training in the high-intensity (D Δ8.3 ± 15.6; E Δ3.8 ± 4.1) and comfortable intensity (D Δ2.9 ± 3.1; E Δ1.2 ± 2.0) groups, whereas gait speed was improved in the comfortable intensity group, without statistically significant group differences. Only the low-intensity group showed improvement on the stability index (Δ -0.6 ± 0.9, p = 0.05). Everyday functional performance significantly improved in all three groups, with the comfortable intensity group showing the greatest improvement. INTERPRETATION: Different training intensities produced improvement in different areas; individualized RAGT intensity adjustment is therefore needed based on the rehabilitation goal.

Association between Low Blood Pressure and Subsequent Risk of Parkinson's Disease in Older Adults Aged ≥75 Years.

INTRODUCTION: The association between blood pressure (BP) and incidence of Parkinson's disease (PD) in older adults remains uncertain. Therefore, this study aimed to investigate the association between BP (high or low) and PD incidence in adults aged ≥75 years. METHODS: In this nationwide population-based cohort study, we enrolled participants aged ≥75 years without a prior PD diagnosis who had undergone health examination provided by the Korean National Health Insurance Service at least once from January 1, 2009, to December 31, 2012. The participants were followed up until December 31, 2019, or the date of their death. The Cox proportional hazards model was used to assess the risk of PD depending on systolic BP (SBP), diastolic BP (DBP), and pulse pressure. RESULTS: Overall, 963,525 participants were enrolled in the analysis and followed up until December 31, 2019, or the date of death (40.7% male, mean age 78.5 ± 3.6 years). The mean SBP and DBP were 131.4 ± 16.7 and 77.9 ± 10.3 mm Hg, respectively. During the 10-year follow-up period, 16,414 (1.7%) newly diagnosed cases of PD were reported. A significant inverse dose-response association was found between SBP and PD incidence. In the subgroup analysis, this association was maintained for most variables, including sex, use of antihypertensive medication, comorbidities, alcohol consumption, physical activity, and body mass index, except for smoking status. CONCLUSION: Lower SBP and DBP were associated with a higher PD incidence in older adults. These results may have substantial implications for determining the optimal BP control target in adults aged ≥75 years.

Medical service utilization by children with physical or brain disabilities in South Korea.

BACKGROUND: Children with physical or brain disabilities experience several functional impairments and declining health complications that must be considered for adequate medical support. This study investigated the current medical service utilization of children expressing physical or brain disabilities in South Korea by analyzing medical visits, expenses, and comorbidities. METHODS: We used a database linked to the National Rehabilitation Center of South Korea to extract information on medical services utilized by children with physical or brain disabilities, the number of children with a disability, medical visits for each child, medical expenses per visit, total medical treatment cost, copayments by age group, condition severity, and disability type. RESULTS: Brain disorder comorbidities significantly differed between those with mild and severe disabilities. Visits per child, total medical treatment cost, and copayments were higher in children with severe physical disabilities; however, medical expenses per visit were lower than those with mild disabilities. These parameters were higher in children with severe brain disabilities than in mild cases. Total medical expenses incurred by newborns to three-year-old children with physical disorders were highest due to increased visits per child. However, medical expenses per visit were highest for children aged 13-18. CONCLUSION: Medical service utilization varied by age, condition severity, and disability type. Severe cases and older children with potentially fatal comorbidities required additional economic support. Therefore, a healthcare delivery system for children with disabilities should be established to set affordable medical costs and provide comprehensive medical services based on disability type and severity.

Deep learning-based fully automated body composition analysis of thigh CT: comparison with DXA measurement.

OBJECTIVES: To compare volumetric CT with DL-based fully automated segmentation and dual-energy X-ray absorptiometry (DXA) in the measurement of thigh tissue composition. METHODS: This prospective study was performed from January 2019 to December 2020. The participants underwent DXA to determine the body composition of the whole body and thigh. CT was performed in the thigh region; the images were automatically segmented into three muscle groups and adipose tissue by custom-developed DL-based automated segmentation software. Subsequently, the program reported the tissue composition of the thigh. The correlation and agreement between variables measured by DXA and CT were assessed. Then, CT thigh tissue volume prediction equations based on DXA-derived thigh tissue mass were developed using a general linear model. RESULTS: In total, 100 patients (mean age, 44.9 years; 60 women) were evaluated. There was a strong correlation between the CT and DXA measurements (R = 0.813~0.98, p < 0.001). There was no significant difference in total soft tissue mass between DXA and CT measurement (p = 0.183). However, DXA overestimated thigh lean (muscle) mass and underestimated thigh total fat mass (p < 0.001). The DXA-derived lean mass was an average of 10% higher than the CT-derived lean mass and 47% higher than the CT-derived lean muscle mass. The DXA-derived total fat mass was approximately 20% lower than the CT-derived total fat mass. The predicted CT tissue volume using DXA-derived data was highly correlated with actual CT-measured tissue volume in the validation group (R2 = 0.96~0.97, p < 0.001). CONCLUSIONS: Volumetric CT measurements with DL-based fully automated segmentation are a rapid and more accurate method for measuring thigh tissue composition. KEY POINTS: • There was a positive correlation between CT and DXA measurements in both the whole body and thigh. • DXA overestimated thigh lean mass by 10%, lean muscle mass by 47%, but underestimated total fat mass by 20% compared to the CT method. • The equations for predicting CT volume (cm3) were developed using DXA data (g), age, height (cm), and body weight (kg) and good model performance was proven in the validation study.

Dual-Layer Detector CT With Virtual Noncalcium Imaging: Diagnostic Performance in Patients With Suspected Wrist Fractures.

OBJECTIVE. The purpose of this study was to evaluate the diagnostic utility of dual-layer CT (DLCT) for evaluating wrist injuries and to compare it with MRI. MATERIALS AND METHODS. The cases of 62 patients with suspected wrist fractures who underwent imaging with both DLCT and MRI from January 2018 through February 2019 were retrospectively reviewed. By means of a calcium suppression algorithm, virtual noncalcium (VNCa) image reconstruction was performed, and the images were reviewed by two readers to identify fractures, bone contusions, and nontraumatic lesions in the radius, ulna, and carpal bones. Sensitivity, specificity, PPV, and NPV were calculated and compared between standard CT and VNCa images with a combination of standard CT and MRI as the reference standard. RESULTS. Use of DLCT with VNCa reconstruction increased the sensitivity of diagnosis of fractures in the radius and carpal bones over that of standard CT alone; occult fractures were detected that were not seen with standard CT. The sensitivity and specificity for detecting radius fracture were 98.1% and 93.8% for DLCT and 96.3% and 93.8% for standard CT. For detecting carpal bone fracture, sensitivity and specificity were 100% and 98.9% for DLCT and 93.8% and 100% for standard CT. VNCa reconstruction also had good diagnostic accuracy with regard to diagnosing nonfracture bone contusions in carpal bones. The accuracy was comparable to that of MRI with sensitivity of 92.9% and specificity of 94.5%. Interreader agreement in interpreting VNCa images was generally good to excellent. CONCLUSION. DLCT with VNCa reconstruction is a promising tool for identifying occult wrist fractures and nonfracture contusion injuries in patients with wrist trauma.

Virtual reality rehabilitation in children with brain injury: a randomized controlled trial.

AIM: To investigate the efficacy of a virtual reality rehabilitation system of wearable multi-inertial sensors to improve upper-limb function in children with brain injury. METHOD: Eighty children (39 males, 41 females) with brain injury including cerebral palsy aged 3 to 16 years (mean age 5y 8mo, SD 2y 10mo) were assessed as part of a multicentre, single-blind, randomized controlled trial. The intervention group received a 30-minute virtual reality intervention and a 30-minute session of conventional occupational therapy while the control group received 60 minutes of conventional occupational therapy per session, with 20 sessions over 4 weeks. The virtual reality rehabilitation system consisted of games promoting wrist and forearm articular movements using wearable inertial sensors. The Melbourne Assessment of Unilateral Upper Limb Function-2 (MA-2), Upper Limb Physician's Rating Scale, Pediatric Evaluation of Disability Inventory Computer Adaptive Test, and computerized three-dimensional motion analysis were performed. RESULTS: Both groups (virtual reality, n=40; control, n=38) significantly improved after treatment compared to baseline; however, the virtual reality group showed more significant improvements in upper-limb dexterity functions (MA-2, virtual reality group: Δ=10.09±10.50; control: Δ=3.65±6.92), performance of activities of daily living, and forearm supination by kinematic analysis (p<0.05). In the virtual reality group, children with more severe motor impairment showed significant improvements compared to those with less severe impairment. INTERPRETATION: The virtual reality rehabilitation system used in this study, which consists of wearable inertial sensors and offers intensive, interactive, and repetitive motor training, is effective in children with brain injury. WHAT THIS PAPER ADDS: Both virtual reality rehabilitation and conventional occupational therapy were effective for upper-limb training. Virtual reality training was superior in improving dexterity, performance of activities of daily living, and active forearm supination motion. The effect of virtual reality training was significant in children with more severe motor impairments.

Relationship between the more-affected upper limb function and daily activity performance in children with cerebral palsy: a cross-sectional study.

BACKGROUND: There are differences in roles between the more-affected and less-affected upper limb of children with cerebral palsy (CP). However, there is a lack of studies of the relationship between the more-affected limb function and activities of daily living (ADL) in children with CP. Thus, the aim of this prospective cross-sectional study was to investigate the relationship between more-affected upper limb function and ADL in children with CP. METHODS: Children with spastic CP (unilateral CP n = 28, bilateral CP n = 31; 34 males, 25 females; mean age ± SD, 6.8 ± 3.1y [range, 3-14y]) participated in this study. Function of the more-affected upper limb was measured using the Melbourne Assessment of Unilateral Upper limb Function, version 2 (MA2) and the Upper Limb Physician's Rating Scale (ULPRS). Performance of daily living activities was measured using the Pediatric Evaluation of Disability Inventory-Computer Adaptive Test (PEDI-CAT). RESULTS: The range, accuracy and fluency dimension of MA2 and ULPRS total scores were moderately correlated with the daily activity domain (r = 0.47, 0.47, 0.56 for MA2 and r = 0.50 for ULPRS, respectively; P < 0.001) rather than the mobility, social/cognitive, and responsibility domains of the PEDI-CAT. ULPRS scores for elbow extension, supination in extension, supination in flexion, and two-handed function were moderately correlated with the PEDI-CAT daily activity domain (r = 0.44, 0.43, 0.41, and 0.49, respectively; P < 0.01). Finger opening and thumb-in-palm deformity of the ULPRS did not correlate with any PEDI-CAT domain. CONCLUSIONS: The MA2 range, accuracy, and fluency domains (rather than dexterity) had the strongest correlations with the PEDI-CAT daily activity domain. Elbow extension, forearm supination, and two-handed function (rather than wrist and finger movements) of the ULPRS had the strongest correlations with the PEDI-CAT daily activity domain.

Fat-suppressed T2 mapping of human knee femoral articular cartilage: comparison with conventional T2 mapping.

BACKGROUND: There is paucity of studies applying fat suppressed (FS) technique to T2 mapping to overcome chemical shift artifacts. The purpose of the study is to difference between FS T2 and conventional T2 mapping and reproducibility of FS T2 mapping in the femoral articular cartilage. METHODS: Eighteen patients who had normal-looking femoral cartilage and underwent knee MRI with conventional T2 and FS T2 mapping were included. T2 values of each mapping were measured by two readers independently from nine regions in the medial femoral condyle (MFC) and lateral femoral condyle (LFC). Each anatomical region was divided by lines at ± 10°, 30°, 50°, 70°, 90°, and 110°. Comparisons of T2 values between conventional and FS T2 mapping were statistically analyzed. The T2 values between FS and conventional T2 mapping in the anterior, central and posterior femoral condyles were compared. RESULTS: The overall femoral condyle T2 values from the FS T2 map were significantly lower than those from the conventional T2 map (48.5ms vs. 51.0ms, p < 0.001). The differences in the T2 values between the two maps were significantly different among the three divisions of the LFC (p = 0.009) and MFC (p = 0.031). The intra-class correlation coefficients indicated higher agreement in the FS T2 map than in the conventional T2 map (0.943 vs. 0.872). CONCLUSIONS: The T2 values of knee femoral cartilage are significantly lower on FS T2 mapping than on conventional T2 mapping. FS T2 mapping is a more reproducible method for evaluating knee femoral cartilage.

Environmental Enrichment Enhances Cav 2.1 Channel-Mediated Presynaptic Plasticity in Hypoxic-Ischemic Encephalopathy.

Hypoxic-ischemic encephalopathy (HIE) is a devastating neonatal brain condition caused by lack of oxygen and limited blood flow. Environmental enrichment (EE) is a classic paradigm with a complex stimulation of physical, cognitive, and social components. EE can exert neuroplasticity and neuroprotective effects in immature brains. However, the exact mechanism of EE on the chronic condition of HIE remains unclear. HIE was induced by a permanent ligation of the right carotid artery, followed by an 8% O2 hypoxic condition for 1 h. At 6 weeks of age, HIE mice were randomly assigned to either standard cages or EE cages. In the behavioral assessments, EE mice showed significantly improved motor performances in rotarod tests, ladder walking tests, and hanging wire tests, compared with HIE control mice. EE mice also significantly enhanced cognitive performances in Y-maze tests. Particularly, EE mice showed a significant increase in Cav 2.1 (P/Q type) and presynaptic proteins by molecular assessments, and a significant increase of Cav 2.1 in histological assessments of the cerebral cortex and hippocampus. These results indicate that EE can upregulate the expression of the Cav 2.1 channel and presynaptic proteins related to the synaptic vesicle cycle and neurotransmitter release, which may be responsible for motor and cognitive improvements in HIE.

Combined use of virtual monochromatic images and projection-based metal artifact reduction methods in evaluation of total knee arthroplasty.

OBJECTIVES: To evaluate the effect of the combined use of virtual monochromatic imaging (VMI) and projection-based metal artifact reduction (PB-MAR) methods on further artifact reduction and image quality in total knee arthroplasty (TKA) patients. METHODS: Fifty-seven knee joints from 36 patients who had a previous history of TKA for bilateral or unilateral knee joints were included in this study. Four sets of images were compared between non-MAR, PB-MAR, VMI, and VMI + PB-MAR. For quantitative analysis, the area, mean attenuation, artifact index (AI), and contrast-to-noise ratio (CNR) were calculated for each protocol. Regarding qualitative analysis, overall artifact and depiction of soft tissue and bony structure were compared using relative visual grading analysis. RESULTS: In the femoral region, the VMI + PB-MAR protocol showed the best MAR performance in quantitative measures including area, mean attenuation, and AI (p < .001). However, MAR protocols with VMI showed significantly lower CNRs than did the protocols without VMI in the tibial region (p < .001). On qualitative analysis, VMI + PB-MAR also showed fewer overall artifacts than did the other two MAR protocols. Soft tissue was best depicted in VMI + PB-MAR protocol, and PB-MAR showed the best performance for the depiction of bony structure (p < .001). CONCLUSIONS: The combined use of VMI and PB-MAR showed better MAR performance than did PB-MAR or VMI alone. In areas with severe metal artifacts, the VMI + PB-MAR and PB-MAR protocols were useful for the evaluation of soft tissue and bone structure, respectively. KEY POINTS: • The combination of artifact reduction methods is effective in reducing metal artifacts in CT. • Soft tissue was best depicted in the combined protocol of projection- and dual-energy-based methods, and projection-based protocol showed the best performance for the depiction of bone structure in case of severe metal artifacts.

Radiographic Follow-Up of Fibrous Dysplasia in 138 Patients.

OBJECTIVE. The purpose of this study was to explore the temporal changes in fibrous dysplasia (FD) at radiographic follow-up. MATERIALS AND METHODS. A total of 138 patients with FD who had undergone extremity radiography at least twice with a minimum 12-month interval between examinations were enrolled in this study. FD was monostotic in 99 patients and polyostotic in 39 patients. Patients were also classified according to skeletal maturity as follows: Patients 16 years old or younger were classified in the skeletally immature group (n = 34), and patients 17 years old or older were classified in the skeletally mature group (n = 104). We compared the initial and follow-up radiographs for the following findings: lesion size, opacity, sclerotic rim, calcification, and trabeculation. RESULTS. Of the 138 patients, radiographic follow-up showed no change in lesion size in 101 patients (73.2%), progression in 31 (22.5%), and regression in six (4.3%). FD in immature bones progressed more often than FD in mature bones (23/34 [67.6%] vs 8/104 [7.7%], respectively; p = 0.000), and polyostotic FD had a greater chance of regressing than monostotic FD (4/39 [10.3%] vs 2/99 [2.0%]; p = 0.032). A temporal change in FD lesion opacity was noticed in a minority of patients (19/138, 13.8%). Variable changes were observed in the sclerotic rim, calcification, and trabeculation. CONCLUSION. The radiographic follow-up of FD showed that approximately a quarter of lesions changed in size over time. Regardless of the change in lesion size, opacity and several morphologic features of FD changed during the follow-up period, which might reflect the histopathologic evolution of FD.

Atypical infectious spondylitis with reduced bone marrow enhancement: "black vertebra sign".

BACKGROUND: A few patients suspected of having infectious spondylitis exhibited a reduced enhancement pattern on postcontrast T1-weighted (T1W) magnetic resonance imaging (MRI). PURPOSE: To investigate the characteristics of infectious spondylitis patients who exhibited reduced vertebral enhancement. MATERIAL AND METHODS: From January 2010 to November 2017, 456 patients with findings suspicious for infectious spondylitis on 706 postcontrast T1W imaging were retrospectively evaluated. When an affected vertebra exhibited markedly reduced enhancement compared to normal bone marrow (BM), the vertebra was termed a "black vertebra." MRI and computed tomography (CT) imaging findings within two-week intervals and the patients' clinical characteristics were reviewed. RESULTS: Ten patients (5 men, 5 women; mean age 66.4 years) whose MRI scans revealed the black vertebra sign were included. Among the 10 patients with black vertebrae, six patients exhibited signal voids in or around the affected vertebral bodies on T2-weighted (T2W) images. Eight patients showed air bubbles on CT images, suggestive of emphysematous infection. However, the typical image findings of infectious spondylitis were uncommon, namely, low BM signal intensity (SI) on T1W images (n=1) and intradiscal fluid-equivalent SI on T2W images (n=5) at an early stage. On follow-up MRI (average interval 7.2 weeks from initial MRI), available for five patients, marked progression of infection was evidenced by increased numbers of affected segments (n=3), low T1 SIs of the affected vertebrae (n=5), and increased contrast enhancement (n=3). Five patients underwent surgery to treat infections not controlled by antibiotics. CONCLUSION: A black vertebra sign on postcontrast T1W imaging seems to reflect an early emphysematous infection.

Ultrasound and Magnetic Resonance Imaging Features of Calcifying Aponeurotic Fibromas.

OBJECTIVES: To report characteristic imaging findings of calcifying aponeurotic fibromas (CAFs) on ultrasound (US) and magnetic resonance imaging (MRI). METHODS: Eight patients with CAF based on our institutional pathology database from 2000 to 2019 were consecutively included. Images were assessed as follows: with plain radiographs for the presence of soft tissue calcifications; with US for the presence of microlithiasis (a nonshadowing hyperechoic focus <3 mm) and discrete calcifications, size, location, margin, echogenicity, and relationship with surrounding structures; and with MRI for the presence of MRI microlithiasis (scattered tiny signal-void dots), margin, signal intensity, contrast enhancement pattern, and relationship with surrounding structures. RESULTS: Calcifying aponeurotic fibromas occurred most commonly in the foot (n = 5), followed by the hand, ankle, and knee, respectively. Half of the lesions (n = 4) showed intralesional calcifications on plain radiographs. On US, all lesions showed microlithiasis. They involved the subcutaneous (n = 5), perifascial (n = 2), and intermuscular (n = 1) layers. Margins were circumscribed (n = 3) or irregular (n = 5), whereas the echogenicity of the underlying tumor matrix was hyperechoic (n = 4), isoechoic (n = 2), or hypoechoic (n = 2). All lesions were abutting (n = 7) or encasing (n = 1) an adjacent tendon. On MRI, all CAFs showed tiny signal-void dots and irregular margins. Signal intensity was mostly hyperintense (n = 5) on T2-weighted images and all hypointense on T1-weighted images. Three lesions showed heterogeneous contrast enhancement, and 3 showed uneven marginal enhancement. CONCLUSIONS: A CAF should be considered a differential diagnosis if a soft tissue mass abutting or encasing the tendon or fascia shows US or MRI microlithiasis.

MRI of Cuboid Pulley Lesion.

OBJECTIVE: The aim of this study was to describe cuboid pulley lesions and associated abnormalities on the basis of clinical findings and the results of MRI examinations of the ankle. MATERIALS AND METHODS: A retrospective search was performed to identify patients who had a cuboid pulley lesion during a 10-year period. A cuboid pulley lesion was defined as bone marrow edema in the lateroplantar ridge of the cuboid that was shown to be wrapped by the peroneus longus tendon on MRI of the ankle. A total of 19 patients (11 men and eight women; mean age, 45.4 years) were included in the group of patients with a cuboid pulley lesion, and 38 age-and sex-matched patients without a cuboid pulley lesion were randomly selected as the control group. We reviewed medical records and assessed MRI findings that could be associated with a cuboid pulley lesion. RESULTS: The mean (± SD) diameter of the cuboid pulley lesion was 8.9 ± 4.7 mm. Cuboid pulley lesions were associated with peroneal tenosynovitis (p < 0.001), Achilles enthesitis (p = 0.004), and a clinical diagnosis of inflammatory arthritis (p < 0.001). Eleven of the 19 patients in the group with cuboid pulley lesions had inflammatory arthritis (either rheumatoid arthritis [n = 7] or spondyloarthritis [n = 4]). The cuboid pulley lesions did not cause localized lateral foot pain and tenderness, except in one patient who had an accompanying stress fracture of the cuboid. CONCLUSION: MRI of the ankle rarely but clearly shows cuboid pulley lesions, which themselves are not likely to cause localized pain, and cuboid pulley lesions show significant associations with peroneal tenosynovitis, Achilles enthesitis, and clinically diagnosed inflammatory arthritis.

Metal Artifact Reduction in Virtual Monoenergetic Spectral Dual-Energy CT of Patients With Metallic Orthopedic Implants in the Distal Radius.

OBJECTIVE: The purpose of this study was to evaluate the image quality of virtual monoenergetic images obtained from dual-layer-detector spectral CT of patients with metallic orthopedic implants of the distal radius. MATERIALS AND METHODS: A retrospective analysis was performed between April 2016 and January 2017. Forty-three consecutively registered patients (33 women, 10 men; mean age, 50.7 ± 15.4 years) with metallic implants for distal radius fractures underwent dual-layer-detector spectral CT. Sixteen virtual monoenergetic image sets ranging from 50 to 200 keV were generated from the single slice with the most pronounced low-attenuation artifact from implants. Image quality was quantitatively assessed on the basis of the attenuation of the artifacts and reference tissue, background image noise, and artifact index. Qualitative assessment included degree of artifact, diagnostic image quality of the periimplant bones, and delineation of fracture lines. The Friedman rank sum test and kappa analysis were used for statistical analysis. RESULTS: There were statistically significant differences in quantitative and qualitative parameters at different monoenergy levels (all p < 0.001). Artifact index was the lowest at 120 keV. Low-attenuation artifacts in the periimplant regions were least pronounced at 110 keV, and the diagnostic image quality of periimplant bone was best at 130 keV. Fracture lines were well delineated in all cases at 80-110 keV (p < 0.001). CONCLUSION: The optimal energy setting for incurring the fewest metallic artifacts and obtaining the best diagnostic image quality from distal radius implants during dual-layer-detector spectral CT is the range of 110-130 keV.

Disproportionate fluid sign as an aid in diagnosing high-grade bursal-sided supraspinatus tendon tear.

Background Deep, high-grade bursal-sided supraspinatus tendon tears are sometimes preoperatively misinterpreted as full-thickness tears on shoulder magnetic resonance imaging (MRI). Purpose To determine the usefulness of disproportionate fluid sign for differentiating high-grade bursal-sided partial-thickness tears from full-thickness tears on conventional MRI. Material and Methods Preoperative MRIs of 198 patients with arthroscopically confirmed high-grade bursal-sided partial-thickness tears and full-thickness tears were independently reviewed by two readers on two occasions. The presence of high-grade bursal-sided partial-thickness tears with a confidence level using a five-point grading scale was assessed based on tear depth alone and also in combination with disproportionate fluid sign, defined as a prominent subdeltoid or subacromial-subdeltoid bursal fluid distension with a relative paucity of effusion in the glenohumeral joint. The sensitivity, specificity, accuracy, and area under the receiver operating characteristic curve (AUC) were calculated, as well as inter-observer reliability. Results The disproportionate fluid sign was identified in 60/74 (81.2%) bursal-sided partial-thickness tears and 9/124 (7.5%) full-thickness tears. The sensitivity and accuracy of the diagnosis of bursal-sided tear were higher when disproportionate fluid sign was used in conjunction with the tear depth, compared with tear depth alone ( P < 0.001). There was excellent inter-observer agreement for disproportionate fluid sign and deep bursal-sided tear. The AUCs were significantly higher in combination with disproportionate fluid sign. Conclusion The disproportionate fluid sign indicates the presence of a deep, high-grade bursal-sided partial-thickness tear, which can be misinterpreted as a full-thickness tear. Thus, it can provide greater diagnostic assistance to less-experienced radiologists and clinicians.

Magnetic resonance imaging follow-up of chondroid tumors: regression vs. progression.

OBJECTIVE: To present magnetic resonance imaging (MRI) evidence of the regression or progression of chondroid tumors and to investigate whether MRI can be used to predict the evolution of chondroid tumors. MATERIALS AND METHODS: Twenty-one patients with enchondromas or atypical cartilaginous tumors who had undergone extremity MRI at least twice with a minimum 12-month interval between the MRIs were enrolled in this study. The diagnosis was based on the radiography and MRI findings. We classified the tumors into the following three groups according to changes between the MRIs: no change (NC), progression (P), and regression (R). We assessed the initial MRI features, including anatomical location, size, endosteal scalloping, peritumoral edema, fat entrapment, and direction of progression or regression. Nineteen of the 21 patients had contrast-enhanced images, and we analyzed the presence of atypical lobular enhancement against typical peripheral or septal enhancement. RESULTS: The R group comprised 11 cases (52%), the P group comprised five cases (24%), and the NC group comprised five cases (24%). None of the MRI features showed statistically significant differences among the groups. Atypical lobular enhancement was observed in the R (6 of 10, 60%) and NC (2 of 5, 40%) groups but not in the P group (0 of 4, 0%), although these differences were not statistically significant. CONCLUSIONS: Chondroid tumors can either regress or progress in the MRI follow-up. Atypical lobular enhancement was seen only in stable or regressing tumors.

Delayed Gadolinium-enhanced MR Imaging of Cartilage: A Comparative Analysis of Different Gadolinium-based Contrast Agents in an ex Vivo Porcine Model.

Purpose To compare the delayed gadolinium-enhanced magnetic resonance (MR) imaging of cartilage (dGEMRIC) indexes acquired with different gadolinium-based contrast agents (GBCAs), with emphasis on the difference in electrical charge, and to evaluate the feasibility of the use of GBCAs other than gadopentetate dimeglumine with a double negative charge (Gd-DTPA2-) as alternatives at dGEMRIC. Materials and Methods Intact porcine patellae (n = 44) were divided into four groups according to GBCA used: Gd-DTPA2-, double negative gadobenate dimeglumine (Gd-BOPTA2-), single negative gadoterate meglumine (Gd-DOTA-), and nonionic gadobutrol (Gd-DT-DO3A). Patellae in each group were further assigned to control (n = 3) or trypsin-treated (n = 8) groups and were immersed in GBCA solutions prepared at a concentration of 2.5 mmol/L. T1 maps were acquired at 10-minute intervals at 0-120 minutes. The difference between postcontrast R1 and precontrast R1 (ΔR) and the time ΔR curves were plotted. Patellae were stained with safranin-O to evaluate the proteoglycan content of the cartilage. A linear mixed-effects model was used to analyze the time ΔR curves, and Student t tests and Mann-Whitney U tests were used to compare dGEMRIC indexes between groups. Results The difference in the estimated slopes of the time ΔR curves between control and trypsin-treated groups were greatest with Gd-BOPTA2-, followed by Gd-DTPA2-, Gd-DOTA-, and Gd-DT-DO3A, with differences in the estimated slopes of 0.037, 0.022, 0.018, and 0.011, respectively. The slope difference between control and trypsin-treated groups was significantly greater with Gd-BOPTA2- (P < .001) and significantly smaller with Gd-DT-DO3A (P = .004) in comparison with that with Gd-DTPA2-. Only the GBCAs with double negative charges showed significant differences in both the T1 measured after equilibration of cartilage with GBCA solution and the ΔR at 90 and 120 minutes between the control and trypsin-treated groups. Conclusion Double negative GBCAs produced better contrast between normal and degenerated cartilage than did those with a single negative charge and nonionic GBCAs at the same concentration for dGEMRIC. Because Gd-BOPTA2-, a high-relaxivity GBCA, showed higher contrast than did Gd-DTPA2-, Gd-BOPTA2-may be useful as an alternative GBCA for dGEMRIC. © RSNA, 2016 Online supplemental material is available for this article.

Diagnostic Accuracy of a Fluid-attenuated Inversion-Recovery Sequence with Fat Suppression for Assessment of Peripatellar Synovitis: Preliminary Results and Comparison with Contrast-enhanced MR Imaging.

Purpose To determine the agreement of fat-suppressed (FS) fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) imaging and contrast material-enhanced (CE) T1-weighted MR imaging for the assessment of peripatellar synovitis. Materials and Methods The institutional review board approved this retrospective study and waived the requirement for patient informed consent. Thirty-three patients with knee pain underwent 3-T MR imaging. The protocol consisted of routine clinical sequences followed by the FLAIR FS sequence (inversion time, 2200 msec) and CE T1-weighted imaging. Visibility of the synovium, synovial thickness, and severity of synovitis in five peripatellar regions were assessed with both sequences. Hoffa synovitis on unenhanced MR images was also analyzed. Then, correlations and agreements between FLAIR FS and CE T1-weighted imaging were evaluated. Diagnostic performance statistics of FLAIR FS and Hoffa synovitis were calculated by using CE T1-weighted imaging as the reference standard. Results Peripatellar synovitis on FLAIR FS images was found in 14 patients by reader 1 and in 17 patients by reader 2. Strong correlations were found between FLAIR FS and CE T1-weighted imaging in the assessment of peripatellar synovitis by both readers (correlation coefficient, 0.675-0.973). With CE T1-weighted imaging as the reference standard, FLAIR FS showed relatively good diagnostic performance for the detection of synovitis of any severity (accuracy of 92.1%-93.9% at the site level and 90.9% at the patient level), while Hoffa synovitis on unenhanced MR images showed moderate sensitivity (78.9%-87.5%) and low specificity (47.1%-64.3%) for the detection of peripatellar synovitis. There was good agreement between the two readers for the synovial visibility (weighted κ = 0.81-0.88) and synovitis assessments (intraclass correlation coefficient = 0.95, weighted κ = 0.72-0.79) on FLAIR FS and CE T1-weighted images. Conclusion Our preliminary study shows that FLAIR FS imaging can potentially enable evaluation of inflamed synovium with high sensitivity and specificity, without the injection of a contrast agent. © RSNA, 2016 Online supplemental material is available for this article.

Measurement of fat content in vertebral marrow using a modified dixon sequence to differentiate benign from malignant processes.

PURPOSE: To determine whether fat-signal-fraction (FF) map using a modified Dixon sequence could help differentiate benign from malignant bone lesions. MATERIALS AND METHODS: Spine magnetic resonance images (MRIs) of 120 consecutive patients were studied by using a 3T MRI with standard T1 -weighted image (T1 WI) and modified-Dixon sequence for FF measurement. There were three groups: a control group (n = 51) with normal vertebrae; a benign group (n = 40) with focal red marrow deposition, Schmorl's nodes, benign compression fracture, or Modic type 1 endplate degeneration; a malignant group (n = 29) with spinal malignancies. The following three parameters were measured on T1 WI and FF map by two radiologists independently: T1 signal intensity (SI), FF and T1 SI of normal disc (SI). Then, Lesion-to-disc ratio (LDR = SI of the lesion/SId ) and FF ratio of lesion and normal marrow were calculated. The mean values of the parameters were compared among the groups and Receiver Operating Characteristic (ROC) curves were analyzed. Then a logistic regression was performed. RESULTS: The FF (2.8%) and FF ratio (0.082) of malignancy were lower than benign lesions (P < 0.001). There was no difference in the LDR between malignancy and Schmorl's nodes (P = 0.795) or a benign compression fracture (P = 0.866). The areas under the ROC curves of FF and FF ratio were 93% and 87%, respectively, which were higher than those of the other parameters used for differentiation (P < 0.001). In logistic regression analyses, FF remained a significant variable that could be used to independently differentiate benign from malignant lesions, with an odds ratio of 1.9 (P < 0.001). CONCLUSION: The FF and FF ratio obtained from FF maps using modified-Dixon sequence could be used to distinguish between benign and malignant causes of focal bone marrow abnormalities when difficulty in the qualitative interpretation of conventional MR images arises. LEVEL OF EVIDENCE: 3 J. MAGN. RESON. IMAGING 2017;45:1534-1544.