Parallel CNN-Deep Learning Clinical-Imaging Signature for Assessing Pathologic Grade and Prognosis of Soft Tissue Sarcoma Patients.

BACKGROUND: Traditional biopsies pose risks and may not accurately reflect soft tissue sarcoma (STS) heterogeneity. MRI provides a noninvasive, comprehensive alternative. PURPOSE: To assess the diagnostic accuracy of histological grading and prognosis in STS patients when integrating clinical-imaging parameters with deep learning (DL) features from preoperative MR images. STUDY TYPE: Retrospective/prospective. POPULATION: 354 pathologically confirmed STS patients (226 low-grade, 128 high-grade) from three hospitals and the Cancer Imaging Archive (TCIA), divided into training (n = 185), external test (n = 125), and TCIA cohorts (n = 44). 12 patients (6 low-grade, 6 high-grade) were enrolled into prospective validation cohort. FIELD STRENGTH/SEQUENCE: 1.5 T and 3.0 T/Unenhanced T1-weighted and fat-suppressed-T2-weighted. ASSESSMENT: DL features were extracted from MR images using a parallel ResNet-18 model to construct DL signature. Clinical-imaging characteristics included age, gender, tumor-node-metastasis stage and MRI semantic features (depth, number, heterogeneity at T1WI/FS-T2WI, necrosis, and peritumoral edema). Logistic regression analysis identified significant risk factors for the clinical model. A DL clinical-imaging signature (DLCS) was constructed by incorporating DL signature with risk factors, evaluated for risk stratification, and assessed for progression-free survival (PFS) in retrospective cohorts, with an average follow-up of 23 ± 22 months. STATISTICAL TESTS: Logistic regression, Cox regression, Kaplan-Meier curves, log-rank test, area under the receiver operating characteristic curve (AUC)，and decision curve analysis. A P-value <0.05 was considered significant. RESULTS: The AUC values for DLCS in the external test, TCIA, and prospective test cohorts (0.834, 0.838, 0.819) were superior to clinical model (0.662, 0.685, 0.694). Decision curve analysis showed that the DLCS model provided greater clinical net benefit over the DL and clinical models. Also, the DLCS model was able to risk-stratify patients and assess PFS. DATA CONCLUSION: The DLCS exhibited strong capabilities in histological grading and prognosis assessment for STS patients, and may have potential to aid in the formulation of personalized treatment plans. TECHNICAL EFFICACY: Stage 2.

Normal bone marrow signal characteristics in whole-body diffusion-weighted images of amateur marathon runners.

Background: Marathon training can reverse bone marrow conversion; however, little is known about the normal bone marrow whole-body diffusion-weighted imaging (WB-DWI) signal characteristics of amateur marathon runners. If marathon training can cause diffuse hyperintensity of bone marrow on WB-DWI is essential for correctly interpreting the diffusion-weighted (DW) images. This study sought to evaluate the WB-DWI signal characteristics of normal bone marrow in amateur marathon runners. Methods: In this prospective cross-sectional study, 30 amateur marathon runners who had trained for over 3 years for regular or half-marathon races and had a running frequency of more than 20 days a month at a distance of more than 100 km per month from the Chengde Marathon Outdoor Sports Association in Hebei, China, and 30 age- and gender-matched, healthy volunteers (the control group) who had no long-term heavy-load sports history were recruited between April 2021 to September 2021. All the subjects underwent WB-DWI (b-value: 0, 800 s/mm2) and lumbar vertebral transverse relaxation time (T2) mapping. The bone marrow WB-DWI signal characteristics were analyzed visually and statistically by chi-square (χ2) tests. The apparent diffusion coefficient (ADC), DWI signal intensity, and T2 values of the bone marrow were quantitatively and statistically analyzed by the independent sample t-test and Mann-Whitney U test. Results: No subjects were excluded from the study. The bone marrow of 30 of the 60 subjects (aged 30-50 years) showed diffuse hyperintensity in the DW images. However, in all 60 subjects, the humeral heads, femoral heads, and great trochanters had low signals. The frequency of diffuse bone marrow DWI hyperintensity was significantly higher in the male amateur marathon runners (50%) than the male controls (5%, P=0.003), but no such significant difference was found between the female amateur marathon runners (100%) and female controls (90%, P>0.99). The DW signal intensity ratios of bone marrow to muscle (SIRBM-muscle) were significantly higher in the male amateur marathon runners than the male controls in the thoracic vertebrae (4.68 vs. 3.57, P=0.021), lumbar vertebrae (4.49 vs. 3.01, P<0.001), sacrum (3.67 vs. 2.62, P=0.002), and hip (3.45 vs. 2.50, P=0.002), but were only significantly higher in the female amateur marathon runners than the female controls in the thoracic vertebrae (7.69 vs. 5.87, P=0.029) and hip (4.76 vs. 3.92, P=0.004). The mean T2 values of the lumbar vertebrae were significantly higher in the male amateur marathon runners than the male controls (116.76 vs. 97.63 ms, P=0.001), but no such significant difference was observed between the female amateur marathon runners and the corresponding controls (118.58 vs. 124.10 ms, P=0.386). Conclusions: Marathon training resulted in diffuse hyperintensity in the bone marrow based on WB-DWI in 50% of the male amateur marathon runners aged 30-50 years. Thus, when WB-DWI is used for bone marrow disease screening, marathon training history should be considered to avoid false-positive diagnoses.

Assessment of 2022 European LeukemiaNet risk classification system in real-world cohort from China.

BACKGROUND: The European LeukemiaNet (ELN) risk classification system for acute myeloid leukemia (AML) patients has been used worldwide. In 2022, the ELN risk classification system modified risk genes including CEBPA mutation status, myelodysplasia-related (MR) gene mutations and internal tandem duplications of FLT3 (FLT3-ITD). METHODS: We include newly diagnosed de novo AML patients at our center from January 2017 to December 2021, regardless of the further treatment received. Clinical data and date of survival were included. Survival analysis were performed using the Kaplan-Meier method, and the log-rank test was used to compare survival between different risk groups. RESULTS: We include 363 newly diagnosed de novo AML patients from 2017 to 2021 to assess the accuracy of the ELN risk classification system. Their survival results show that the ELN-2022 risk classification system is not superior to the ELN-2017 version; for patients with FLT3-ITD mutations but without FLT3 inhibitor treatment, their survival is similar to the ELN-2022 adverse risk group. The ELN-2022 risk classification system cannot accurately clarify ECOG performance status (PS) 2-4 patients, especially in the ELN-2022 favorable risk group. CONCLUSION: The ELN-2022 risk stratification system may not be appropriate for patients unable to receive intensive therapy or FLT3 inhibitor; more real-world data is needed to straify patients with worse ECOG PS and inferior intensive therapy.

Monitoring early responses to neoadjuvant chemotherapy and the factors affecting neoadjuvant chemotherapy responses in primary osteosarcoma.

Background: This study sought to predict the early responses to neoadjuvant chemotherapy (NACT) of patients with primary conventional osteosarcoma (COS) using the apparent diffusion coefficient (ADC) and to evaluate the factors affecting the tumor necrosis rate (TNR). Methods: The data of 41 patients who underwent magnetic resonance imaging (MRI) and diffusion-weighted imaging sequence scans before NACT, 5 days after the end of the first phase of NACT, after the end of the whole course of chemotherapy, were prospectively collected. ADC1 refers to the ADC before chemotherapy, ADC2 refers to the ADC after the first phase of chemotherapy, and ADC3 refers to the ADC before surgery. The change in values before and after the first phase of chemotherapy was calculated as follows: ADC2-1 = ADC2 - ADC1. The change in values before and after the last phase of chemotherapy was calculated as follows: ADC3-1 = ADC3 - ADC1. The change in values after the first phase and the last phase of chemotherapy was calculated as follows: ADC3-2 = ADC3 - ADC2. We recorded the patient characteristics, including age, gender, pulmonary metastasis, alkaline phosphatase (ALP), and lactate dehydrogenase (LDH). The patients were divided into the following 2 groups based on their histological TNR after postoperative: (I) the good-response group (≥90% necrosis, n=13) and (II) the poor-response group (<90% necrosis, n=28). Changes in the ADCs were compared between the good-response and poor-response groups. The different ADCs between the 2 groups were compared, and a receiver operating characteristic analysis was performed. A correlation analysis was performed to assess the correlations of the clinical features, laboratory features, and different ADCs with patients' histopathological responses to NACT. Results: The ADC2 (P<0.001), ADC3 (P=0.004), ADC3-1 (P=0.008), ADC3-2 (P=0.047), and ALP before NACT (P=0.019) were significantly higher in the good-response group than in the poor-response group. The ADC2 [area under the curve (AUC) =0.723; P=0.023], ADC3 (AUC =0.747; P=0.012), and ADC3-1 (AUC =0.761; P=0.008) showed good diagnostic performance. Based on the univariate binary logistic regression analysis, the ADC2 (P=0.022), ADC3 (P=0.009), ADC2-1 (P=0.041), and ADC3-1 (P=0.014) were correlated with the TNR. However, based on the multivariate analysis, these parameters were not significantly correlated with the TNR. Conclusions: In patients with COS who are undergoing neoadjuvant chemotherapy, the ADC2 is a promisingindicator for predicting tumor response to chemotherapy in early.

Dexamethasone enhances venetoclax-induced apoptosis in acute myeloid leukemia cells.

Acute myeloid leukemia (AML) therapies have been significantly improved by the development of medicines that can target BCL-2. On the other hand, non-recurrent alterations in oncogenic pathways and gene expression patterns have already been linked to therapeutic resistance to venetoclax therapy. Bone marrow mesenchymal stromal cells (BM-MSCs) support leukemic cells in preventing chemotherapy-induced apoptosis by mitochondrial transfer in leukemic microenvironment. In this study, we investigated the enhancement of the antitumor effect of BCL-2 inhibitor venetoclax by dexamethasone. In particular, dexamethasone had no significant effect on the viability of AML cells, but dexamethasone combined with venetoclax could significantly increase the apoptosis of AML cells induced by venetoclax. When AML cells were co-cultured with BM-MSCs, dexamethasone combined with venetoclax showed additional anti-tumor effect compared to venetoclax alone. Venetoclax increased reactive oxygen species level in co-cultured AML cells, contributed to transfer more mitochondria from BM-MSCs to AML cells and protect AML cells from apoptosis. Dexamethasone combined with venetoclax induced more apoptosis, but dexamethasone reduced the venetoclax-induced reactive oxygen species level in AML cells and reduced the transfer of mitochondria from BM-MSCs to AML cells. This may lead to a diminished protective effect of BM-MSCs on AML cells. Together, our findings indicated that venetoclax in combination with dexamethasone could be a promising therapy in AML.

Comparing the blood oxygen level-dependent fluctuation power of benign and malignant musculoskeletal tumors using functional magnetic resonance imaging.

Purpose: The aim of this study is to compare the blood oxygen level-dependent (BOLD) fluctuation power in 96 frequency points ranging from 0 to 0.25 Hz between benign and malignant musculoskeletal (MSK) tumors via power spectrum analyses using functional magnetic resonance imaging (fMRI). Materials and methods: BOLD-fMRI and T1-weighted imaging (T1WI) of 92 patients with benign or malignant MSK tumors were acquired by 1.5-T magnetic resonance scanner. For each patient, the tumor-related BOLD time series were extracted, and then, the power spectrum of BOLD time series was calculated and was then divided into 96 frequency points. A two-sample t-test was used to assess whether there was a significant difference in the powers (the "power" is the square of the BOLD fluctuation amplitude with arbitrary unit) of each frequency point between benign and malignant MSK tumors. The receiver operator characteristic (ROC) analysis was used to assess the diagnostic capability of distinguishing between benign and malignant MSK tumors. Results: The result of the two-sample t-test showed that there was significant difference in the power between benign and malignant MSK tumor at frequency points of 58 (0.1508 Hz, P = 0.036), 59 (0.1534 Hz, P = 0.032), and 95 (0.247 Hz, P = 0.014), respectively. The ROC analysis of mean power of three frequency points showed that the area of under curve is 0.706 (P = 0.009), and the cutoff value is 0.73130. If the power of the tumor greater than or equal to 0.73130 is considered the possibility of benign tumor, then the diagnostic sensitivity and specificity values are 83% and 59%, respectively. The post hoc analysis showed that the merged power of 0.1508 and 0.1534 Hz in benign MSK tumors was significantly higher than that in malignant ones (P = 0.014). The ROC analysis showed that, if the benign MSK tumor was diagnosed with the power greater than or equal to the cutoff value of 1.41241, then the sensitivity and specificity were 67% and 68%, respectively. Conclusion: The mean power of three frequency points at 0.1508, 0.1534, and 0.247 Hz may potentially be a biomarker to differentiate benign from malignant MSK tumors. By combining the power of 0.1508 and 0.1534 Hz, we could better detect the difference between benign and malignant MSK tumors with higher specificity.

The signal intensity characteristics of normal bone marrow in diffusion weighted imaging at various menstrual status women.

PURPOSE: Diffuse hyperintensities of the bone marrow in whole-body diffusion-weighted (DW) imaging (DWI) have been encountered more frequently in females aged 21-50 compared to elder females or men. Therefore, we aimed to visually evaluate DWI among pre-, peri- and postmenopausal women and to verify whether it correlates also quantitatively with hormonal status. METHOD: The prospective study was approved by our institutional review board and informed consent was obtained in a total of 70 healthy premenopausal, perimenopausal, and postmenopausal women aged 40-58 years from February 2017 to October 2017. The bone marrow DW imaging signal characteristics were visually evaluated in comparison to the erector spinae muscle. Imaging data were acquired using a 1.5 T MRI yielding signal intensity values from a DWI-pulse sequence (b-value of 800 s/mm2; apparent diffusion coefficient (ADC) maps from b-values of 0-800 s/mm2), and a T2 mapping sequence covering the L2-L4 lumbar vertebrae. Serous estradiol (E2), follicle stimulating hormone (FSH), and luteinizing hormone (LH) were measured through venous blood assay. The relationship of the mean DW signal intensity (SIDWI) with T2 values, female hormone level, and mean ADC were analyzed using Spearman's rho test. RESULTS: The proportion of diffuse DWI hyperintensities of the bone marrow was significantly higher in premenopausal (91% (21/23)) women compared to peri- (75% (18/24)) and postmenopausal (8% (2/23)) women. A positive correlation was observed for the mean SIDWI (median [interquartile range], 47.33 [30.14]) and mean T2 (mean ± SD, 121.01 ± 13.54) (r = 0.438, p < 0.001) as well as for the mean SIDWI and E2 (median [interquartile range], 52.45 [92.78]) (r = 0.407, p < 0.001). A negative correlation was observed for the mean SIDWI and serous FSH (median [interquartile range], 15.55 [42.08]) as well as for the mean SIDWI and serous LH (median [interquartile range], 6.96 [31.06]) (r = -0.557, p < 0.001; r = -0.535, p < 0.001; respectively), but no significant correlation was found for mean SIDWI and mean ADC (mean ± SD, 599.36 ± 82.70) (r = 0.099, p = 0.415). A negative correlation was also encountered for the mean T2 values and serous FSH (r = -0.339, p = 0.004) as well as for the mean T2 values and serous LH (r = -0.281, p = 0.018). CONCLUSIONS: The mean SIDWI correlates positively with mean T2 and serous E2 values, while there's no significant correlation with mean ADC, indicating that T2 shine-through effects might interfere with bone marrow signaling on DW images. Knowledge of the bone marrow signal characteristics changing in DW images in close relationship with menstrual status is essential to correctly interpret DWI in clinical practice.

Primary malignancy in giant cell tumor of thoracic vertebrae: A case report.

RATIONALE: Primary malignancy in giant cell tumor of bone (PMGCTB) is extremely unusual. PMGCTB in the thoracic vertebrae is particularly rare. PATIENTS CONCERNS: A 23-year-old man was admitted with a chief complaint of chest pain associated with cough for approximately 3 days. Physical examination revealed a palpable, immobile, tender, 7 cm mass in the right paravertebral area of the thoracolumbar spine. DIAGNOSIS: Computed tomography images revealed an osteolytic, expansive, and eccentric lesion on the vertebral bodies and right accessory processes with spinal cord compression in the thoracic vertebra, with right rib also having bone destruction. Magnetic resonance imaging revealed multiple fluid-fluid levels occupying more than one-third of the lesions. On the basis of the imaging and pathological findings, the final pathological diagnosis was PMGCTB with aneurysmal bone cyst. INTERVENTIONS: The patient underwent successful wide spondylectomy of T9/10 to remove the tumor, and adjuvant chemotherapy based on the protocol used for osteosarcoma. OUTCOMES: After 4 years of follow-up, there is no clinical or radiological evidence of recurrence. LESSONS: PMGCTB is difficult to distinguish from giant cell tumor of bone. PMGCTB should be considered when lesions appear with multiple fluid-fluid levels and soft tissue mass.

Synovium as a widespread pathway to the adjacent joint in undifferentiated high-grade pleomorphic sarcoma of the tibia: A case report.

RATIONALE: Undifferentiated high-grade pleomorphic sarcoma (UPS), originated from bone, is a rare tumor, accounting for 2% to 5% of all primary maligment bone neoplasms. Skip lesion can be found in undifferentiated high-grade pleomorphic sarcoma of bone (UPS-B). However, the direct invasion across the articular synovium to bone has not been reported previously. PATIENT CONCERNS: We report an unusual case of a 65-year-old man complained of a year history of pain, swelling, and limitation of activity in the left knee joint. At the proximal tibia, there was extensive invasion of articular synovium, which provides a direct anatomic pathway for the tumor invasion to the adjacent bone, including patella and femoral condyle. DIAGNOSES: Magnetic resonance imaging was important in defining the marrow involvement and joint invasion, including the thickening articular synovium. Subsequent pathological examination confirmed the diagnosis of UPS. INTERVENTIONS: The patient underwent an extensive resection of the knee joint, except for the patellar. OUTCOMES: After operation, routine chemotherapy was performed. Unfortunately, half a year later, soft tissue swelling of whole thigh was found. Then this patient came our hospital again. Positron emission tomography imaging showed there was recurrence of UPS with lung metastasis. A week later, this patient died. LESSONS: In contrast to frequent infiltration pathway, the articular synovium as a media for this tumor spread is rare. This study adds a better understanding of this direct invasion way to the medical literature.

Tumor Tissue Detection using Blood-Oxygen-Level-Dependent Functional MRI based on Independent Component Analysis.

Accurate delineation of gliomas from the surrounding normal brain areas helps maximize tumor resection and improves outcome. Blood-oxygen-level-dependent (BOLD) functional MRI (fMRI) has been routinely adopted for presurgical mapping of the surrounding functional areas. For completely utilizing such imaging data, here we show the feasibility of using presurgical fMRI for tumor delineation. In particular, we introduce a novel method dedicated to tumor detection based on independent component analysis (ICA) of resting-state fMRI (rs-fMRI) with automatic tumor component identification. Multi-center rs-fMRI data of 32 glioma patients from three centers, plus the additional proof-of-concept data of 28 patients from the fourth center with non-brain musculoskeletal tumors, are fed into individual ICA with different total number of components (TNCs). The best-fitted tumor-related components derived from the optimized TNCs setting are automatically determined based on a new template-matching algorithm. The success rates are 100%, 100% and 93.75% for glioma tissue detection for the three centers, respectively, and 85.19% for musculoskeletal tumor detection. We propose that the high success rate could come from the previously overlooked ability of BOLD rs-fMRI in characterizing the abnormal vascularization, vasomotion and perfusion caused by tumors. Our findings suggest an additional usage of the rs-fMRI for comprehensive presurgical assessment.

Dysregulation of Fra1 expression by Wnt/ß-catenin signalling promotes glioma aggressiveness through epithelial-mesenchymal transition.

Aberrant expression of Fos-related antigen-1 (Fra1) is commonly elevated in various malignant cancers and is strongly implicated in invasion and metastasis. However, the molecular mechanisms underlying its dysregulation in human glioma remain poorly understood. In the present study, we demonstrate that up-regulation of Fra1 plays a crucial role in the glioma aggressiveness and epithelial-mesenchymal transition (EMT) activated by Wnt/ß-catenin signal pathway. In glioma cells, activation of Wnt/ß-catenin signalling by Wnt3a administration obviously induced EMT and directly activated the transcription of Fra1. Phenotype experiments revealed that up-regulation of Fra1 induced by Wnt/ß-catenin signalling drove the EMT of glioma cells. Furthermore, it was found that the cisplatin resistance acquired by Wnt/ß-catenin signalling activation depended on increased expression of Fra1. Analysis of clinical specimens verified a positive correlation between Fra1 and ß-catenin as well as a poor prognosis in glioma patients with double-high expressions of them. These findings indicate that an aberrant Wnt/ß-catenin signalling leads to the EMT and drug resistance of glioma via Fra1 induction, which suggests novel therapeutic strategies for the malignant disease.

Characterizing the Blood Oxygen Level-Dependent Fluctuations in Musculoskeletal Tumours Using Functional Magnetic Resonance Imaging.

This study characterized the blood oxygen level-dependent (BOLD) fluctuations in benign and malignant musculoskeletal tumours via power spectrum analyses in pre-established low-frequency bands. BOLD MRI and T1-weighted imaging (T1WI) were collected for 52 patients with musculoskeletal tumours. Three ROIs were drawn on the T1WI image in the tumours' central regions, peripheral regions and neighbouring tissue. The power spectrum of the BOLD within each ROI was calculated and divided into the following four frequency bands: 0.01-0.027 Hz, 0.027-0.073 Hz, 0.073-0.198 Hz, and 0.198-0.25 Hz. ANOVA was conducted for each frequency band with the following two factors: the location of the region of interest (LoR, three levels: tumour "centre", "peripheral" and "healthy tissue") and tumour characteristic (TC, two levels: "malignant" and "benign"). There was a significant main effect of LoR in the frequencies of 0.073-0.198 Hz and 0.198-0.25 Hz. These data were further processed with post-hoc pair-wise comparisons. BOLD fluctuations at 0.073-0.198 Hz were stronger in the peripheral than central regions of the malignant tumours; however, no such difference was observed for the benign tumours. Our findings provide evidence that the BOLD signal fluctuates with spatial heterogeneity in malignant musculoskeletal tumours at the frequency band of 0.073-0.198 Hz.

Signal characteristics of normal adult bone marrow in whole-body diffusion-weighted imaging.

BACKGROUND: Knowledge of the signal characteristics of normal adult bone marrow in whole-body diffusion-weighted (DW) images (WB-DWI) is essential for correctly interpreting DW images in clinical practice; however, these factors have not yet been clearly determined. PURPOSE: To evaluate the signal characteristics of normal adult bone marrow in WB-DWI, to correlate these characteristics with age and gender, and to determine the causes of these phenomena. MATERIAL AND METHODS: Ninety-eight healthy volunteers underwent WB-DWI (b = 0 and 800 s/mm(2)). Two radiologists visually evaluated the signal characteristics of bone marrow in DW images separately. One radiologist measured the apparent diffusion coefficient (ADC) of the thoracic and lumbar vertebrae, bilateral femur (including head, neck, and proximal and distal femoral shaft), bilateral humeral head, ilium, and scapula. The signal characteristics of normal bone marrow were analyzed. RESULTS: The visual evaluation results of DW images indicated that hyperintensity of bone marrow was more frequently seen in women aged 21-50 years (68.4%) than in men aged 21-50 years (3.3%) (P < 0.001), men aged 51-81 years (5.9%) (P < 0.001), and women aged 51-81 years (15.4%) (P = 0.001). However, no statistically significant difference was found between men and women aged 51-81 years (P = 0.565). The ADC of bone marrow was significantly higher in women than in men aged 21-50 years. Bone marrow ADC showed significant negative correlation with age in women but not in men. CONCLUSION: The signal intensity of bone marrow varies with age and gender in DW images. ADC and the T2 shine-through effect contributed to the bone marrow signal intensity in DW images, and the latter effect may predominate.

Differentiating benign from malignant bone tumors using fluid-fluid level features on magnetic resonance imaging.

OBJECTIVE: To analyze different fluid-fluid level features between benign and malignant bone tumors on magnetic resonance imaging (MRI). MATERIALS AND METHODS: This study was approved by the hospital ethics committee. We retrospectively analyzed 47 patients diagnosed with benign (n = 29) or malignant (n = 18) bone tumors demonstrated by biopsy/surgical resection and who showed the intratumoral fluid-fluid level on pre-surgical MRI. The maximum length of the largest fluid-fluid level and the ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane were investigated for use in distinguishing benign from malignant tumors using the Mann-Whitney U-test and a receiver operating characteristic (ROC) analysis. Fluid-fluid level was categorized by quantity (multiple vs. single fluid-fluid level) and by T1-weighted image signal pattern (high/low, low/high, and undifferentiated), and the findings were compared between the benign and malignant groups using the χ(2) test. RESULTS: The ratio of the maximum length of the largest fluid-fluid level to the maximum length of bone tumors in the sagittal plane that allowed statistically significant differentiation between benign and malignant bone tumors had an area under the ROC curve of 0.758 (95% confidence interval, 0.616-0.899). A cutoff value of 41.5% (higher value suggests a benign tumor) had sensitivity of 73% and specificity of 83%. CONCLUSION: The ratio of the maximum length of the largest fluid-fluid level to the maximum length of a bone tumor in the sagittal plane may be useful to differentiate benign from malignant bone tumors.

Multiple plexiform schwannomas in the plantar aspect of the foot: case report and literature review.

BACKGROUND: Plexiform schwannoma (PS) is a rare, peripheral nerve sheath tumor arranged in a plexiform pattern. CASE PRESENTATION: We report an unusual case of a 19-year-old woman, who complained of pain in the plantar aspect of the left foot. Magnetic resonance image (MRI) demonstrates three solitary nodules of varying sizes in the deep soft tissue of the plantar aspect of the foot that are homogeneously isointense to skeletal muscle on T1-weighted images and hyperintense on T2-weighted fat-suppressed images, especially the rim of the lesion. Subsequent pathological examination confirmed the diagnosis of PS. CONCLUSION: MRI characteristic plays an important role in detecting this rare lesion. A review of the literature on PS is also presented.