Cementless total knee arthroplasty (TKA) has regained attention in younger, active, and obese patients, supported by advances in implant design, porous coating, and 3D printing technologies. However, the success of cementless fixation depends on adequate initial mechanical stability and subsequent osseointegration, making the assessment of bone quality at the implant–bone interface essential. Although central dual-energy X-ray absorptiometry (DXA) is useful for evaluating systemic bone health, it has been reported to inadequately reflect the localized peripheral bone quality of the distal femur and proximal tibia. Therefore, cementless TKA candidate selection requires direct evaluation of the bone quality around the knee joint, particularly at the bone resection site. This narrative review summarizes the preoperative and intraoperative methods available for knee-specific bone quality assessment in the context of cementless TKA selection. Various X-ray-based methods are accessible but limited by two-dimensional projection and protocol variability. Peripheral DXA allows localized bone mineral density measurement but lacks standardization and remains two-dimensional. Magnetic resonance imaging (MRI) has potential for assessing marrow composition and trabecular microarchitecture, but evidence supporting its use in cementless TKA selection remains limited. By contrast, computed tomography (CT)-based assessment is considered the most practical modality, offering three-dimensional evaluation and region-specific analysis. Hounsfield unit analysis on conventional CT can be readily integrated into the routine preoperative workflow, while quantitative CT and dual-energy CT provide more quantitative evaluation through volumetric bone mineral density measurement. Intraoperative assessment has the advantage of directly evaluating the implant bed; however, conventional tactile assessment remains subjective, and visual grading systems and device-based assessments have been proposed to overcome this limitation. Nevertheless, no standardized method has yet been established, and further research is needed. CT-based assessment is the most practical current modality, and intraoperative assessment is gaining objectivity. The integration of these methods with artificial intelligence-driven multi-modal assessment is expected to enable more precise and patient-specific cementless TKA candidate selection.

BACKGROUND:With the increasing utilization of newer-generation cementless total knee arthroplasty (TKA), the preoperative prediction of bone quality has emerged as a significant concern. Recognizing such limitations of central bone mineral density, attention has turned to Hounsfield units (HU), a measure of the standardized linear attenuation coefficient in computed tomography (CT) imaging, known for its ability to estimate bone marrow density specifically around the knee joint. Consequently, this study aims to investigate the correlation between preoperative dual-energy CT (DECT) HU measurements of the distal femur and the actual bone strength. We hypothesized that DECT-derived HU would (1) significantly correlate with biomechanical bone strength and (2) serve as a reliable tool for identifying suitable candidates for cementless TKA. MATERIALS AND METHODS:In this prospective study, 190 knees that underwent primary posterior stabilized TKA between May 2022 and May 2023 were included. HU of the distal femur was assessed using DECT scan, which utilizes material decomposition to differentiate bone from soft tissue or bone marrow, providing more accurate bone quality assessment than conventional CT, and the actual bone strength of the corresponding bone fragment was measured using an indentation test that serves as a validated surrogate for traditional compression testing. The association between HU and actual bone strength was evaluated using correlation and linear regression analyses. To further assess its diagnostic utility in identifying candidates for cementless TKA, receiver operating characteristic (ROC) curve analysis with calculation of the area under the curve (AUC) was performed to determine both accuracy and the optimal cutoff value. RESULTS:The DECT HU value in coronal plane showed significant correlations with bone strength measured by indentation testing (r = 0.67, p < 0.01). In linear regression analysis, coronal HU was independently predictive of bone strength (β = 0.62, R² = 0.45, p < 0.01). Furthermore, coronal HU showed good discriminative ability for identifying candidates suitable for cementless TKA (AUC = 0.82, 95% CI 0.766-0.880), with an optimal cutoff of 72 HU yielding sensitivity of approximately 73% and specificity of 74%. CONCLUSIONS:This study demonstrates that DECT HU is a promising marker for periarticular bone quality, given its strong correlation with distal femoral bone strength and excellent performance in predicting suitability for cementless TKA. However, considering our simplified model, ethnic diversity, and CT scanner variability, these factors should be taken into account before using this threshold as a definitive clinical guide. LEVEL OF EVIDENCE:II; Prospective diagnostic study.

Background and Objectives: Adequate bone quality is essential for promoting initial bone ingrowth and preventing early migration during cementless total knee arthroplasty (TKA). However, gold-standard criteria for identifying suitable bone strength have yet to be established. Dual-energy computed tomography (DECT)-based volumetric bone mineral density (vBMD) is an emerging tool for assessing bone quality. This study aimed to determine whether DECT-derived vBMD can accurately predict suitable bone strength for cementless TKA. Materials and Methods: A total of 190 patients undergoing primary TKA with a standardized posterior-stabilized implant were prospectively enrolled. Prior to TKA, DECT-derived vBMD was measured in the femoral box region. Actual bone strength was evaluated using an indentation test on resected femoral box specimens. Correlation and linear regression analyses were performed to assess the relationship between DECT vBMD and actual bone strength. Receiver operating characteristic (ROC) curve analysis and area under the curve (AUC) calculations were used to determine the optimal cut-off value and diagnostic accuracy of DECT vBMD in identifying candidates suitable for cementless TKA. Results: DECT-derived vBMD exhibited a strong correlation with actual bone strength (correlation coefficient = 0.719, p < 0.01), while linear regression analysis revealed a moderate association (R2 = 0.51, p < 0.01). In addition, it demonstrated excellent diagnostic performance in predicting adequate bone quality for cementless TKA, yielding an AUC of 0.984, with a sensitivity of 91.9% and a specificity of 92.0%. Conclusions: DECT-derived vBMD is a reliable and accurate tool for assessing bone strength around the knee and predicting the suitable bone quality for cementless TKA.

The efficacy of an MRI-based deep learning algorithm (DLA) for detecting acute ischemic stroke (AIS) was evaluated across readers with diverse medical backgrounds, because DLA performance may be user-dependent. This retrospective, multi-reader, multi-case crossover study included 407 MRI scans obtained from a single institution between April and June 2021. Nine readers with different backgrounds— radiology residents (1–2 years of radiology training), clinicians (no radiology training), and board-certified non-neuroradiologists (completed residency training)—independently read MRI scans, both with and without DLA detection probability. The ground truth was established by consensus among three neuroradiologists. The area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, specificity, diagnostic confidence (0–4), and inter-reader agreement were compared between the groups with and without DLA. In total, 407 patients (mean age, 66 years ± 16; 200 men) with 95 AIS (23

Background and Objectives: The use of cementless total knee arthroplasty (TKA) is increasing, but established methods for assessing bone quality to prevent early failure remain undefined. Current preoperative assessments using central bone mineral density (BMD) do not accurately reflect peripheral bone quality, and intraoperative evaluation is subjective. This study aimed to establish objective assessment methods by analyzing the correlations between a novel visual grading system, CT Hounsfield units (HU), and actual bone strength. Materials and Methods: This prospective study included 131 patients undergoing posterior-stabilized TKA. We developed a novel visual grading system (Excellent, Good, Fair, Poor) based on femoral cutting surface characteristics. CT HUs were measured preoperatively by an assisting surgeon in the box bone area. Femoral box specimens underwent indentation testing to determine their actual bone strength. Minimum Required Strength (MRS) was defined at 2.5-fold the patient’s body weight, and Estimated Withstanding Strength (EWS) was determined by scaling first failure load using area ratios. Patients were classified as “cementless suitable” (EWS > MRS) or “cemented mandatory” (EWS < MRS). Correlations were assessed using Spearman’s rank correlation for visual grade and Pearson correlation for Hounsfield units. ROC curve analysis determined diagnostic accuracy. Results: Visual grade exhibited an exceptionally robust relationship to bone strength (Spearman ρ = 0.903, p < 0.01), whereas HU showed substantial correlation (Pearson r = 0.660, p < 0.01, R2 = 0.435). Visual grading achieved excellent diagnostic accuracy (AUC = 0.974, sensitivity 95.1%, specificity 95.9%) using “Good” grade as cutoff. HU demonstrated AUC of 0.938 with 92.7% sensitivity and 81.6% specificity at a cutoff value of 65.2. Conclusions: Our novel visual grading system and CT HU demonstrated excellent correlations with actual distal femoral bone strength and outstanding diagnostic performance for identifying cementless TKA candidates. Unlike traditional subjective intraoperative assessments such as the “thumb test”, this system provides objective visual criteria directly correlated with actual bone strength. Preoperative HU screening with intraoperative visual grading can help prevent early failure.

To develop and validate a deep-learning-based algorithm for automatic identification of anatomical landmarks and calculating femoral and tibial version angles (FTT angles) on lower-extremity CT scans. In this IRB-approved, retrospective study, lower-extremity CT scans from 270 adult patients (median age, 69 years; female to male ratio, 235:35) were analyzed. CT data were preprocessed using contrast-limited adaptive histogram equalization and RGB superposition to enhance tissue boundary distinction. The Attention U-Net model was trained using the gold standard of manual labeling and landmark drawing, enabling it to segment bones, detect landmarks, create lines, and automatically measure the femoral version and tibial torsion angles. The model’s performance was validated against manual segmentations by a musculoskeletal radiologist using a test dataset. The segmentation model demonstrated 92.16

RATIONALE AND OBJECTIVES:To determine whether virtual noncontrast (VNC) images derived from three-phase dynamic dual-energy CT (DECT) imaging can reliably substitute true noncontrast (TNC) images in assessing muscle and fat with automatic segmentation software. MATERIALS AND METHODS:The data from 476 dynamic liver DECT examinations performed between April 2019 and December 2020 were retrospectively analyzed. VNC images were generated from arterial (VNCa), portal-venous (VNCp), and delayed (VNCd) phase images. Automated software measured muscle, visceral fat (VF), and subcutaneous fat (SF) areas. Sarcopenia was defined using muscle-related indices. Differences in muscle and fat measurements, as well as sarcopenia prevalence, between TNC and VNC images were assessed using paired t tests and McNemar tests, respectively. RESULTS:The average age of the 476 patients (307 men) was 58.4±12.5years. Muscle density and area differed significantly between the TNC and VNC images; TNC images showed higher mean muscle density and smaller skeletal muscle area (SMA) than all VNC images (P<0.001). VF and SF attenuations were significantly lower on TNC images than on all VNC images (P<0.001). The proportions of sarcopenic patients did not differ significantly between TNC and VNCp or VNCd, regardless of the muscle index used. CONCLUSION:Despite significant differences in muscle and fat attenuations between TNC and VNC images, VNCp and VNCd may be acceptable alternatives for measuring muscle and fat areas. However, TNC and VNC images should not be used interchangeably for assessing tissue attenuation or specific muscle components such as LAMA or NAMA.

Objectives To compare the image quality and diagnostic performance of low-dose CT urography to that of concurrently acquired conventional CT using dual-source CT. Methods This retrospective study included 357 consecutive CT urograms performed by third-generation dual-source CT in a single institution between April 2020 and August 2021. Two-phase CT images (unenhanced phase, excretory phase with split bolus) were obtained with two different tube current-time products (280 mAs for the conventional-dose protocol and 70 mAs for the low-dose protocol) and the same tube voltage (90 kVp) for the two X-ray tubes. Iterative reconstruction was applied for both protocols. Two radiologists independently performed quantitative and qualitative image quality analysis and made diagnoses. The correlation between the noise level or the effective radiation dose and the patients' body weight was evaluated. Results Significantly higher noise levels resulting in a significantly lower liver signal-to-noise ratio and contrast-to-noise ratio were noted in low-dose images compared to conventional images (P < .001). Qualitative analysis by both radiologists showed significantly lower image quality in low-dose CT than in conventional CT images (P < .001). Patient's body weight was positively correlated with noise and effective radiation dose (P < .001). Diagnostic performance for various diseases, including urolithiasis, inflammation, and mass, was not different between the two protocols. Conclusions Despite inferior image quality, low-dose CT urography with 70 mAs and 90 kVp and iterative reconstruction demonstrated diagnostic performance equivalent to that of conventional CT for identifying various diseases of the urinary tract. Advances in knowledge Low-dose CT (25% radiation dose) with low tube current demonstrated diagnostic performance comparable to that of conventional CT for a variety of urinary tract diseases.

Background: The purpose of this study is to compare turbo spin echo diffusion-weighted images in radial trajectory (BLADE DWI) with multi-shot echoplanar imaging (RESOLVE DWI) for imaging the metastatic lesion in the pelvic bone to find a correlation between ADC values and standardized uptake values (SUVs) of FDG uptake in PET/CT. The study also seeks to compare the values of metastatic lesions with those of benign bone lesions, specifically red marrow hyperplasia. Methods: The retrospective IRB-approved study included patients with bone metastasis and red marrow hyperplasia in the pelvic bone who underwent 3.0 T MRI with BLADE/RESOLVE DWI sequences and F-18 FDG PET/CT within one month. BVC (best value comparator) was used in determining the nature of bone lesions. Apparent diffusion coefficient (ADC) and standardized uptake value (SUV) were measured by a radiologist and a nuclear medicine physician. MRI image quality was graded with a Likert scale regarding the visualization of the sacroiliac joint, sacral neural foramen, hamstring tendon at ischial tuberosity, and tumor border. Signal-to-noise ratio (SNR) and imaging time were compared between the two DWIs. Mean, peak, and maximum SUVs between metastatic and benign red marrow lesions were compared. SUVs and ADC values were compared. AUROC analyses and cut-off values were obtained for each parameter. Mann–Whitney U, Spearman’s rho, and Kolmogorov–Smirnov tests were applied using SPSS. Results: The final study group included 58 bone lesions (19 patients (male: female = 6:13, age 52.5 ± 9.6, forty-four (75.9%) bone metastasis, fourteen (24.1%) benign red marrow hyperplasia). ADCs from BLADE and RESOLVE were significantly higher in bone metastasis than red marrow hyperplasia. BLADE showed higher ADC values, higher anatomical scores, and higher SNR than RESOLVE DWI (p < 0.05). Imaging times were longer for BLADE than RESOLVE (6 min 3 s vs. 3 min 47 s, p < 0.05). There was a poor correlation between ADC values and SUVs (correlation coefficient from 0.04 to 0.31). The AUROC values of BLADE and RESOLVE MRI ranged from 0.892~0.995. Those of PET ranged from 0.877~0.895. The cut-off ADC values between the bone metastasis and red marrow hyperplasia were 355.0, 686.5, 531.0 for BLADE min, max, and average, respectively, and 112.5, 737.0, 273.0 for RESOLVE min, max, and average, respectively. The cut-off SUV values were 1.84, 5.01, and 3.81 for mean, peak, and max values, respectively (p < 0.05). Conclusions: Compared with RESOLVE DWI, BLADE DWI showed improved image quality of pelvic bone MRI in the aspect of anatomical depiction and SNR, higher ADC values, albeit longer imaging time. BLADE and RESOLVE could differentiate bone metastasis and red marrow hyperplasia with quantifiable cut-off values. Further study is necessary to evaluate the discrepancy between the quantifiers between PET and MRI.

AbstractBackgroundAlthough sarcopenia has been recognized as a predictor of mortality in elderly patients with hip fracture, the association of thigh fat and muscle with cardiovascular (CV) outcome remains unclear. We examined the impact of computed tomography (CT)‐derived shape features of thigh fat and muscle on major adverse CV events (MACE) in elderly patients with hip fracture.MethodsWe conducted a retrospective analysis of consecutive patients aged ≥65 years who presented with hip fracture confirmed on pelvic bone CT scan and underwent hip fracture surgery at our institution from April 2019 to December 2021. The cross‐sectional area (CSA) and compactness (CM) of both the muscle and fat at the upper‐thigh level were calculated from two‐dimensional CT images using AVIEW Research (v1.1.38, Coreline Soft, Co. Ltd, Seoul, South Korea). The shape features of thigh fat and muscle were categorized into four groups based on the combination of CSA and CM: fat CSA (fat area [FA])/fat CM (FCM), muscle CSA (muscle area [MA])/muscle CM (MCM), FA/MCM and MA/FCM. In each of them, subjects were categorized into four subgroups: high CSA/high CM, high CSA/low CM, low CSA/high CM and low CSA/low CM. The primary outcome was MACE after 30 days of surgery, defined as a composite of all‐cause death, acute myocardial infarction, stroke or hospitalization for heart failure.ResultsOf 356 patients enrolled (median age, 82 years; 76.7% females), 72 (20.2%) had MACE over a median follow‐up of 13.1 months (ranges 5.9–21.0 months). Patients with MACE had a significantly lower median FA (193.7 vs. 226.2 cm2, P < 0.0001) and FCM (0.443 vs. 0.513, P = 0.001) compared with those without MACE, but no significant differences were found in MA, MCM and FA–MA ratio between the two groups. In a multivariate Cox regression analysis, low FA (<240.1 cm2) (adjusted hazard ratio [HR] 2.99, 95% confidence interval [CI] 1.39–6.44, P = 0.005) and low FCM (<0.477) (adjusted HR 2.00, 95% CI 1.10–3.63, P = 0.023) were associated with an increased risk of MACE. Among the shape phenotypes of thigh fat and muscle, the thigh fat phenotype of low FA/low FCM (adjusted HR 3.13, 95% CI 1.81–5.42, P < 0.0001 [reference, high FA/high FCM]) was found to be an independent predictor of MACE.ConclusionsIn elderly patients with fragility hip fracture, thigh CT‐derived measures of FA and FCM may provide useful prognostic information for predicting adverse CV outcomes.

To assess the T1 and T2 values of bone marrow lesions in spine and pelvis derived from magnetic resonance fingerprinting (MRF) and to evaluate the differences in values among bone metastasis, red marrow and fatty marrow. Sixty patients who underwent lumbar spine and pelvic MRI with magnetic resonance fingerprinting were retrospectively included. Among eligible patients, those with bone metastasis, benign red marrow deposition and normal fatty marrow were identified. Two radiologists independently measured the T1 and T2 values from metastatic bone lesions, fatty marrow, and red marrow deposition on three-dimensional-magnetic resonance fingerprinting. Intergroup comparison and interobserver agreement were analyzed. T1 relaxation time was significantly higher in osteoblastic metastasis than in red marrow (1674.6 ± 436.3 vs 858.7 ± 319.5, p < .001). Intraclass correlation coefficients for T1 and T2 values were 0.96 (p < 0.001) and 0.83 (p < 0.001), respectively. T2 relaxation time of osteoblastic metastasis and red marrow deposition had no evidence of a difference (osteoblastic metastasis, 57.9 ± 25.0 vs red marrow, 58.0 ± 34.4, p = 0.45), as were the average T2 values of osteolytic metastasis and red marrow deposition (osteolytic metastasis, 45.3 ± 15.1 vs red marrow, 58.0 ± 34.4, p = 0.63). We report the feasibility of three-dimensional-magnetic resonance fingerprinting based quantification of bone marrow to differentiate bone metastasis from red marrow. Simultaneous T1 and T2 quantification of metastasis and red marrow deposition was possible in spine and pelvis and showed significant different values with excellent inter-reader agreement. T1 values from three-dimensional-magnetic resonance fingerprinting might be a useful quantifier for evaluating bone marrow lesions.

Musculoskeletal pain is a significant contributor to disability. The mechanism and target of the treatment should be optimized by imaging, but currently no accepted gold standard exists to image pain. In addition to end-organ pathology, other mediators also contribute to nociception, such as angiogenesis, axonal extension, immunologic modulation, and central sensitization. Recent research indicates that local inflammation is a significant contributor to pain in the extremities; therefore, we focus here on edema-like marrow signal intensity (ELMSI). We examine both the relevance of ELMSI for pain and novel imaging techniques.

We present a rare case of myoepithelioma in the subcutaneous layer of the shoulder with ultrasonography (US) and magnetic resonance imaging (MRI). US showed a lobulated hyperechoic mass, leading to an impression of lipoma. MRI showed the mass with low signal intensity on T1-weighted images (T1WI), high signal intensity on fat-suppressed T2-weighted images (T2WI), intermediate signal intensity on T2WI, and intense enhancement with adjacent fascial thickening. Imaging findings of soft tissue myoepithelioma have not been established. We report its US and MRI features mimicking features from a lipomatous tumor to infiltrative malignancy. Although soft tissue myoepithelioma has nonspecific image findings to confirm its diagnosis, some findings may help to make the differential diagnosis. Preoperative pathologic confirmation is recommended in a soft tissue neoplasm.

Objectives: This research aims to apply an auditory display for tumor imaging using fluorescence data, discuss its feasibility for in vivo tumor evaluation, and check its potential for assisting enhanced cancer perception. Methods: Xenografted mice underwent fluorescence imaging after an injection of cy5.5-glucose. Spectral information from the raw data was parametrized to emphasize the near-infrared fluorescence information, and the resulting parameters were mapped to control a sound synthesis engine in order to provide the auditory display. Drag–click maneuvers using in-house data navigation software-generated sound from regions of interest (ROIs) in vivo. Results: Four different representations of the auditory display were acquired per ROI: (1) audio spectrum, (2) waveform, (3) numerical signal-to-noise ratio (SNR), and (4) sound itself. SNRs were compared for statistical analysis. Compared with the no-tumor area, the tumor area produced sounds with a heterogeneous spectrum and waveform, and featured a higher SNR as well (3.63 ± 8.41 vs. 0.42 ± 0.085, p < 0.05). Sound from the tumor was perceived by the naked ear as high-timbred and unpleasant. Conclusions: By accentuating the specific tumor spectrum, auditory display of fluorescence imaging data can generate sound which helps the listener to detect and discriminate small tumorous conditions in living animals. Despite some practical limitations, it can aid in the translation of fluorescent images by facilitating information transfer to the clinician in in vivo tumor imaging.

Purpose We aimed to analyze the prevalence, causes, and clinical settings of 4-year critical radiologic reports (CRRs) notified from the musculoskeletal section of the radiology department. Then, we investigated the communication outcomes. Methods This study was approved by our institutional review board. We retrospectively included 175 musculoskeletal CRRs from our database between January 2017 and December 2020. The CRRs were analyzed by two musculoskeletal radiologists, who categorized the CRRs by clinical setting (emergency department(ED) patient, outpatient, and inpatient), body part, type of image modality, reason for CRR, incidental lesion, and clinical outcome. The clinical outcome was retrieved from the electronic medical records. Results The 175 musculoskeletal CRRs accounted for 5.4% of the CRRs (n = 3217) available in the study period. Most CRRs (94.9%, 166/175) corresponded to the musculoskeletal system, while the remaining ones (5.1%, 9/175) corresponded to the non-musculoskeletal system. In addition, the spine, extremities, and thoracic cage accounted for 52.6%, 40.6%, and 1.7% of the musculoskeletal CRRs, respectively. Moreover, most patients presented to the ED (50.3%, 88/175), followed by inpatients (30.9%, 54/175), and outpatients (18.9%, 33/175). The CRR reasons included missed fracture (54.3%), suspected malignancy (16%), clinical emergency (10.3%), unexpected infection/inflammation (11.4%), and others (8%). Furthermore, 11 (6.3%) incidental lesions were not related to the primary imaging purpose. Referring clinicians actively acknowledged 80% of the CRRs. The loss to follow-up action was the highest in the ED patients (35.2%, 31/88; p < 0.001), being significantly higher than that in outpatients (6.1%, 2/33) and inpatients (3.7%, 2/54). Conclusion Missed fractures were the most common cause of musculoskeletal CRRs. ED showed prevalence in musculoskeletal CRRs and reflected the highest loss to follow-up action. ED physicians should pay more attention to CRRs to enhance patient care.

Purpose: This study aimed to conduct a comparison between 2D thin section intermediate-weighted Dixon turbo spin echo (TSE), 3D intermediate-weighted SPACE (sampling perfection with application-optimized contrasts using flip angle evolutions) TSE, and 2D fat-suppressed T2-weighted TSE in terms of their image quality and diagnostic performance for ankle ligament evaluation. Materials and Methods: Thirty-eight ankle MRI studies were retrospectively analyzed. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the multiplanar reformation images of the sequences were obtained. For each sequence, the subjective image quality and the diagnostic performance for ankle ligament tear were analyzed. Results: The Dixon demonstrated the highest CNR both between ligament and fluid and between ligament and bone marrow. The 3D SPACE showed the highest SNR of the ligament. Regarding subjective image quality, it was significantly higher in the T2-weighted image than it was in the SPACE (p < 0.05), while there was no significant difference between the Dixon and the SPACE. The Dixon showed the highest sensitivity for anterior talofibular ligament (ATFL) tear (80.0%; 95% confidence interval [CI], 64.4-92.3) and deep deltoid ligament (DL) tear (86.4%; 95% CI, 65.1-97.1), and it showed the highest specificity for ATFL tear (70.2%; 95% CI, 59.3-79.7). The interobserver agreement was moderate to good (intraclass correlation coefficient [ICC], 0.50-0.93) in most cases except for the SNR of deep DL (ICC of 0.35-0.62). Conclusion: For ankle ligament evaluation, the 2D thin section Dixon provides adequate image quality with high SNR and CNR and the highest sensitivity for detecting tears.

Introduction: Adequate bone quality is essential for long term biologic fixation of cementless total knee arthroplasty (TKA). Recently, vertebral bone quality evaluation using dual-energy computed tomography (DECT) has been introduced. However, the DECT bone mineral density (BMD) in peripheral skeleton has not been correlated with Hounsfield units (HU) or central dual-energy X-ray absorptiometry (DXA), and the accuracy remains unclear. Materials and methods: Medical records of 117 patients who underwent TKA were reviewed. DXA was completed within three months before surgery. DECT was performed with third-generation dual source CT in dual-energy mode. Correlations between DXA, DECT BMD and HU for central and periarticular regions were analyzed. Receiver operating characteristic (ROC) curves were plotted and area under the curve (AUC), optimal threshold, and sensitivity and specificity of each region of interest (ROI) were calculated. Results: Central DXA BMD was correlated with DECT BMD and HU in ROIs both centrally and around the knee (all p < 0.01). The diagnostic accuracy of DECT BMD was higher than that of DECT HU and was also higher when the T-score for second lumbar vertebra (L2), rather than for the femur neck, was used as the reference standard (all AUC values: L2 > femur neck; DECT BMD > DECT HU, respectively). Using the DXA T-score at L2 as the reference standard, the optimal DECT BMD cut-off values for osteoporosis were 89.2 mg/cm3 in the distal femur and 78.3 mg/cm3 in the proximal tibia. Conclusion: Opportunistic volumetric BMD assessment using DECT is accurate and relatively simple, and does not require extra equipment. DECT BMD and HU are useful for osteoporosis screening before cementless TKA.

The diagnostic tool for Kümmell’s disease (KD), including the intravertebral vacuum cavity on imaging, is still limited. The purpose of this study was to find other magnetic resonance imaging (MRI) findings that could help the diagnosis of KD. A total of 289 patients (103 males and 186 females with a mean age of 69 ± 15 years) with thoracolumbar compression fracture were included. Medical records were reviewed to note symptom duration. MRIs were analyzed for intraosseous cavities (IOC), prevertebral soft-tissue changes (PreSC), posterior wall fracture (PoF), and posterior ligamentous complex tear (PLCT). KD was diagnosed based on surgical findings or clinical report. MRI findings and symptom duration in the presence or absence of KD were compared with chi-squared test, logistic regression, and Student’s t-test and area under the curve (AUC) analyses. KD was diagnosed in 55 cases. IOC was noted in 33 (60%) cases in the KD group and 82 (35%) cases in non-KD group. Definite PreSC was noted in 44 (80%) cases in the KD group and 94 (40%) cases in the non-KD group. PoF was seen in 36 (65%) and 140 (60%) cases, and PLCT was seen in 7 (13%) and 26 (11%) cases in KD and non-KD groups, respectively. The IOC and PreSC MRI findings were significantly correlated with KD (p < 0.001), but not with PoF (p = 0.539) or PLCT (p = 0.814). AUC of combined IOC and PreSC was 0.72, higher than that of IOC alone (0.63) or PreSC alone (0.69) (both p < 0.001). The average duration of symptom was 64 days in the KD group and 14 days in the non-KD group (p < 0.001). Positive IOC and PreSC findings were associated with longer symptom duration (p < 0.001). Prevertebral soft-tissue changes and intraosseous cavity are associated with KD. Combined findings of prevertebral soft-tissue changes and intraosseous cavity can help the diagnosis of KD.

Purpose This study aimed to stratify risk factors and vein levels for postoperative deep vein thrombosis (DVT) after lower-extremity orthopedic surgery. Methods Ninety-nine patients who underwent Doppler ultrasonography after lower-extremity orthopedic surgery were enrolled. Medical records were reviewed for anesthesia duration, type of surgery, body weight, height, and cardiovascular risk factors (including history of smoking, diabetes mellitus or hypertension, blood pressure, and total cholesterol and high-density lipoprotein [HDL] cholesterol levels), and the DVT treatment. Ultrasound diagnosis of DVT was made according to a routine protocol. The relationships between selected factors and the presence of DVT were assessed using univariate and multivariate regression analyses. Results Thirty-three (33%) patients were found to have calf DVT. The mean age, weight, and height of the non-DVT and postoperative DVT patients were 55.1 years versus 65.4 years, 70.5 kg versus 61.2 kg, and 163.3 cm versus 157.0 cm, respectively. Total cholesterol/HDL levels in the non-DVT and DVT patients were 70.6/20.7 mg/dL and 90.8/26.0 mg/dL, retrospectively. Systolic and diastolic blood pressure in the non-DVT and DVT patients were 133.6/80.2 mm Hg and 132.2/78.1 mmHg, respectively. The mean duration of anesthesia was 173.9 versus 199.9 minutes, and the operative time was 136.4 minutes versus 161.0 minutes. Older age (P=0.005) and lower body weight (P=0.002) were significantly associated with postoperative DVT. No other significant between-group differences were found (P>0.05). The patients with ultrasound-identified DVT received antithrombotic treatment. None of them had distant thromboembolism. Conclusion After lower-extremity orthopedic surgery, the calf veins in elderly patients with low body weight are susceptible to thrombosis; they would most likely benefit from postoperative ultrasonography.