Reliable diagnosis of liposarcoma by magnetic resonance imaging (MRI) is essential for surgical planning. The purpose of this study was to correlate radiologists' certainty of the diagnosis of liposarcoma on musculoskeletal MRI with pathology results.Between January 2001 and February 2009, 105 patients who radiologically suggested liposarcoma on their MRI reports were retrospectively reviewed. Among them, pathologically confirmed 64 patients (benign, 42; malignant, 22) were included. Two musculoskeletal radiologists reviewed MR reports and classified these into 3 groups according to the degree of certainty of liposarcoma (CL) by consensus: C1, high; C2, undetermined; and C3, low. Classified data were compared with pathology results.The number of cases in each group was C1, 32; C2, 12; and C3, 20. Group C1 included 17 liposarcomas (53%), 7 lipomas, 4 other sarcomas, 2 hibernomas, 1 abscess, and 1 epidermal cyst. There were 11 lipomas (92%) and one liposarcoma in C2. In C3, all patients had lipomas. Fifteen (47%) of 32 variable benign or malignant tumors were incorrectly diagnosed as liposarcomas.On the diagnosis of liposarcoma, the radiologists' high degree of CL showed high agreement. However, nonadipose tumors were sometimes misdiagnosed as liposarcomas with a high CL. Therefore, we should consider other soft tissue tumors and benign lipomas for the differential diagnosis of liposarcoma.
Self-distillation (SD) is the process of training a student model using the outputs of a teacher model, with both models sharing the same architecture. Our study theoretically examines SD in multi-class classification with cross-entropy loss, exploring both multi-round SD and SD with refined teacher outputs, inspired by partial label learning (PLL). By deriving a closed-form solution for the student model's outputs, we discover that SD essentially functions as label averaging among instances with high feature correlations. Initially beneficial, this averaging helps the model focus on feature clusters correlated with a given instance for predicting the label. However, it leads to diminishing performance with increasing distillation rounds. Additionally, we demonstrate SD's effectiveness in label noise scenarios and identify the label corruption condition and minimum number of distillation rounds needed to achieve 100% classification accuracy. Our study also reveals that one-step distillation with refined teacher outputs surpasses the efficacy of multi-step SD using the teacher's direct output in high noise rate regimes.
Background Plain radiography serves a pivotal role in diagnosing axial spondyloarthritis. However, a broad range of diagnostic performance of plain radiography has been reported. Purpose To perform a systematic review and meta-analysis to measure the diagnostic performance of plain radiography for sacroiliitis in patients suspected of having axial spondyloarthritis using magnetic resonance imaging (MRI) findings as the reference standard. Material and Methods Studies comparing radiography and MRI in the diagnosis of sacroiliitis in patients suspected of having axial spondyloarthritis were searched in PubMed and EMBASE. Additionally, studies analyzed SPondyloaArthritis Caught Early (SPACE), DEvenir des Spondylarthropathies Indifferenciées Récentes (DESIR), GErman Spondyloarthritis Inception Cohort (GESPIC), and South Swedish Arthritis Treatment Group (SSATG) cohorts were manually searched. Pooled sensitivity and specificity of radiography were calculated by using a bivariate random-effects model. Meta-regression analyses were performed to identify the sources of heterogeneity. Results Eight eligible studies with 1579 patients were included. The pooled sensitivity and specificity of radiography were 0.55 (95% confidence interval [CI] = 0.40–0.69) and 0.87 (95% CI = 0.72–0.95). The meta-regression analyses showed prospective study design and criteria for MRI positivity considering only active bone marrow edema were associated with lower sensitivity. Conclusion The plain radiography showed low sensitivity and reasonable specificity in diagnosis of sacroiliitis in patients suspected of having axial spondyloarthritis.
The various pathologic conditions detected at CT and MRI and subsumed by the term sacral tumor include primary bone tumors, sacral canal tumors and metastases. Among these, metastases are much more common than primary bone tumors, of which chordoma is the most common. Although the imaging findings of sacral tumors are nonspecific, a patient's age and sex, and specific findings such as calcification or fluid-fluid levels, can help radiologists in their differential diagnosis. We describe the imaging findings of primary sacral tumors, emphasizing the MRI findings.
Purpose: To compare the MR imaging findings of experimentally induced pyogenic arthritis of rabbit knees with the corresponding histopathologic findings. Materials and Methods: Infection was induced in 20 rabbit knees by direct intra-articular injection of Staphylococcus aureus. The animals were divided into four groups of five rabbits each, and spin-echo sagittal T1-and T2-weighted images were obtained 3 days, 1 week, 2 weeks, and 4 weeks, respectively, after staphylococcal inoculation. MR-pathologic correlation was performed, with emphasis on intra-and extra-articular soft tissue lesion characteristics. Soft tissue lesion signal intensity (SI) was classified as low, iso, or high on the basis of that of muscle, and high SI was further subdivided into three categories. Results: At T2-weighted imaging, all soft tissue lesions showed high SI. Pathologic examination revealed the presence of inflammatory cell infiltration (n=2), abscess (n=1), granulation tissue (n=3), fibrosis (n=11), edema (n=4), congestion (n=9), and joint fluid (n=11). Except for the abscess, these lesions were irregular in shape and had variable SI (grade 1-3) and at T2WI could not, therefore, be differentiated. In nine kness, extraarticular soft-tissue lesions were demonstrated at T2WI and correlated with infectious soft tissue lesions such as inflammatory cell infiltration, abscess, granulation tissues and fibrosis; and non-infectious reactive soft tissue changes such as edema and congestion. Conclusion: In pyogenic arthritis, the MR imaging features of soft tissue lesions varied and were nonspecific, depending on the histopathologic abnormalities observed. Our results indicate that in assessing the extent of pyogenic arthritis with MR imaging, caution is required.
To describe the clinical and optical coherence tomography (OCT) features of a macular hole (MH) or its precursor lesion in patients treated with systemic antiestrogen agents.We reviewed the medical history of the patient, ophthalmic examination, and both fundus and OCT findings.Three female patients receiving antiestrogen therapy sought treatment for visual disturbance.All of the patients showed foveal cystic changes with outer retinal defect upon OCT.Visual improvement was achieved through surgery for the treatment of MH in two patients.Antiestrogen therapy may result in MH or its precursor lesion, in addition to perifoveal refractile deposits.OCT examination would be helpful for early detection in such cases.
A retrospective investigation.We evaluated and compared the radiation exposure caused by using the fluoroscopy-guided transforaminal and caudal approaches of lumbosacral epidural steroid injection (ESI).Only a few studies focused on the radiation exposure to patients who underwent lumbosacral ESI for pain management.A total of 228 patients (83 males, 145 females; mean age, 63.3 y) who received lumbosacral ESI were included. Transforaminal ESI was performed in 181 patients (67 males, 114 females; mean age, 61.3 y) and caudal ESI was used in 47 patients (16 males, 31 females; mean age, 69.7 y). All ESIs were performed under a single-plane fluoroscopic guidance by 1 musculoskeletal radiologist. The kerma-area product (KAP) and fluoroscopy time were recorded in all patients. Both measurements were correlated and compared for each approach.KAP was 3.02-1048.2 μGy m (mean, 101.7 μGy m; median, 67.8 μGy m) for transforaminal ESI and 16.0-604.5 μGy m (mean, 101.8 μGy m; median, 54.6 μGy m) for caudal ESI. The fluoroscopy time was 11-161 seconds for transforaminal ESI (mean, 36.0 s; median, 29 s) and 4-78 seconds (mean, 18.2 s; median, 13 s) for caudal ESI. KAP and fluoroscopy time were positively correlated for each approach (P<0.001). Fluoroscopy time was significantly longer for transforaminal ESI (correlation coefficient=-0.77, P=0.000). After correction for the fluoroscopy time, KAP was less in transforaminal ESI than in caudal ESI (correlation coefficient=0.74, P=0.000).The longer the fluoroscopy time, the greater the KAP in both transforaminal and caudal ESIs. The fluoroscopy time for transforaminal ESI was longer than that for caudal ESI. However, KAP of transforaminal ESI was less than that of the caudal ESI, after being corrected for the length of fluoroscopy time.
Background: Diaphragm movement is well correlated with inspired volume of the lung. Dexmedetomidine (DEX) has less effect on respiratory functions than other sedatives. The objective of this study was to investigate diaphragmatic movement using ultrasound (US) during DEX infusion for sedation in spontaneously breathing patients undergoing unilateral upper limb surgery. Methods: A total of 33 consecutive patients were enrolled in this study. Patients were sedated using DEX with ipsilateral axillary brachial nerve plexus block. Diaphragmatic activity was evaluated using diaphragmatic thickening at end-inspiration (TEI), diaphragmatic thickening at end-expiration (TEE), and diaphragmatic thickening fraction (DTF) measured by diaphragmatic US at three time-points; T0, baseline; T1, after DEX sedation; and T2, after DEX recovery. Supplementary oxygen was applied with a simple mask at 5 L/min. Peripheral oxygen saturation (SpO2), end tidal CO2 (EtCO2), and respiratory rate (RR) were recorded. Results: TEI and TEE showed no significant changes during the study period (P = 0.394 and P = 0.205, respectively). DTF was maintained at both T0 and T1 (P = 1.000). At recovery after DEX infusion discontinued, DTF was increased by 3.85%, although such increase was not statistically significant (T0 vs. T2, P = 0.525). SpO2 remained above 99% and EtCO2 remained below 36 mmHg. Desaturation episodes were not observed during the study period. Conclusions: Results of this study showed that DEX sedation did not affect the diaphragmatic movement in situation of decreased RR induced by DEX. This finding implies that DEX-induced sedation does not result in clinically significant respiratory depression.
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