Vertebral bone marrow edema in magnetic resonance imaging correlates with bone healing histomorphometry in (sub)acute osteoporotic vertebral compression fracture

Diagnostic model for distinguishing fresh or old osteoporotic vertebral compression fractures based on modified computed tomography window: a retrospective cohort study

PURPOSE

To develop and validate a Computed Tomography (CT) -based nomogram for distinguishing fresh from old osteoporotic vertebral compression fractures (OVCFs), with magnetic resonance imaging (MRI) as the reference standard.

METHODS

In this retrospective study, OVCF patients from The First Affiliated Hospital of Chongqing Medical University (August 2022-December 2023) were analyzed. Modified CT window parameters (width: 400; level: 200) were applied to quantify vertebral features, including CT values, height reduction, endplate integrity, trabecular sparsity, Schmorl's nodes, and high-density shadows. Predictive variables were selected via univariate and multivariate logistic regression, followed by nomogram construction. Model performance was assessed using receiver operating characteristic (ROC) curves (area under the curve, AUC), calibration plots, Hosmer-Lemeshow testing, and decision curve analysis (DCA). 10-fold cross-validation was used to evaluate the generalization performance of the model.

RESULTS

The nomogram incorporated seven imaging biomarkers, achieving AUCs of 0.941 (training cohort) and 0.974 (validation cohort). The calibration accuracy was assessed using the Hosmer-Lemeshow test (χ²=3.30, P = 0.95). DCA demonstrating significant clinical utility across probability thresholds. In cross-validation, the mean AUC on the validation sets was 0.911 ± 0.080 (mean ± standard deviation).

CONCLUSION

The proposed CT-based nomogram achieved adequate performance in identifying fresh and old OVCFs.

Impact of Cement Distribution on the Efficacy of Percutaneous Vertebral Augmentation for Osteoporotic Fractures: Assessment with an MRI-Based Reference Marker

BACKGROUND

No studies have evaluated the impact of the cement distribution as classified on the basis of the fracture bone marrow edema area (FBMEA) in magnetic resonance imaging (MRI) on the efficacy of percutaneous vertebral augmentation (PVA) for acute osteoporotic vertebral fractures.

METHODS

The clinical data of patients with acute, painful, single-level thoracolumbar osteoporotic fractures were retrospectively analyzed. The bone cement distribution on the postoperative radiograph was divided into 4 types according to the distribution of the FBMEA on the preoperative MRI. The primary outcomes were the postoperative visual analog scale (VAS) for pain and Oswestry Disability Index (ODI) scores. Cement leakage, adjacent vertebral fractures (an important concern in complications after vertebroplasty and a subset of new fractures), and recollapse of the treated vertebra were also evaluated.

RESULTS

A total of 128 patients, 80.5% of whom were female, were included and had follow-up for 24 months. The mean patient age (and standard deviation) was 74.2 ± 8.6 years. The cement distribution was classified as Type I in 18 patients, Type II in 26, Type III in 46, and Type IV in 38. At the primary time point (6 months), there was a significant difference in the ODI score favoring the Type-III and Type-IV groups compared with the Type-I and Type-II groups (adjusted 95% confidence interval [CI]: Type I versus Type II, -2.40 to 4.50; Type I versus Type III, 1.35 to 7.63; Type I versus Type IV, 1.27 to 7.92; Type II versus Type III, 0.67 to 6.21; Type II versus Type IV, 0.63 to 6.46; adjusted p < 0.0083), whereas no significant differences were found between the 4 groups in the VAS pain score. The Type-II and Type-IV groups had a higher incidence of cement leakage, and the Type-III and Type-IV groups had a lower incidence of vertebral recollapse.

CONCLUSIONS

An adequate distribution of bone cement is advantageous for functional improvement, short-term pain relief, and a lower rate of vertebral recollapse. The FBMEA appears to be a feasible reference marker for evaluating the performance of the PVA procedure.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Capacitive biophysical stimulation improves the healing of vertebral fragility fractures: a prospective multicentre randomized controlled trial

BACKGROUND

Capacitively coupling electric fields (CCEF) is a method of non-invasive biophysical stimulation that enhances fracture repair and spinal fusion. This multicentre randomized controlled trial aimed to further examine the roles of CCEF in (1) the resolution of vertebral bone marrow oedema (VBME) using a follow-up MRI study and (2) pain relief, analgesic drug consumption and quality of life improvement in stimulated patients who were referred with acute vertebral fragility fractures (VFFs) compared to non-stimulated patients.

METHODS

Between September 2016 and December 2019, patients who were referred to the spine centres that participated in this multicentre randomized clinical study with acute VFFs of type OF1 or OF2 were included in the present study. All the VFFs were conservatively managed according to Good Clinical Practice. Moreover, the patients were randomized into two groups: the CCEF group received, as an adjunct to the clinical study protocol, biophysical stimulation with a CCEF device (Osteospine, IGEA) for 8 h per day for 60 days, whereas the control group was treated according to the clinical study protocol. At baseline (T0), the 30-day follow-up (T1), the 60-day follow-up (T2), and the 6-month follow-up (T3), each patient underwent clinical evaluation using the Visual Analogue Scale (VAS) for Pain and the Oswestry Disability Index (ODI). Analgesic therapy with paracetamol 1000 mg tablets for 7 days-or longer, depending on the pain intensity-was performed; patients were required to report their paracetamol consumption on a specific sheet between study day 8 to 180 days of follow-up. MRI studies of the thoracolumbar spine were performed at 0 (T0), 30 (T1) and 60 days of follow-up (T2) using a 1.5-T MRI system in all of the centres that took part in the study. For each VBME area examined via MRI, the vertebral body geometry (i.e. anterior wall height/posterior wall height and vertebral kyphosis) were assessed.

RESULTS

A total of 66 patients (male: 9, 13.63%; mean age: 73.15 years old) with 69 VFFs were included in the present study and randomized as follows: 33 patients were included in the control group and the remaining 33 patients were randomized into the CCEF group. In the CCEF group, good compliance with CCEF therapy was observed (adherence = 94%), and no adverse effects were recorded. In the stimulated patients, faster VBME resolution and significantly less vertebral body collapse during follow-up were observed compared to the control patients. Moreover, in the active group, faster pain reduction and improvement in the ODI mean score were observed. Stimulated patients also reported a significantly lower paracetamol consumption rate from the third follow-up after treatment until the 6-month follow-up. In terms of sex-related differences, in the CCEF group, VBME showed a faster resolution in male patients compared with females.

CONCLUSION

Biophysical stimulation with CCEF, as an adjunct to traditional conservative treatment, is a useful tool to hasten the VBME resolution process and prevent vertebral body deformation. These MRI findings also correlate with faster back pain resolution and quality of life improvement. From the third follow-up after treatment until the 6-month follow-up, stimulated patients reported a significantly lower paracetamol consumption than control patients, even though back pain and quality of life showed no significant differences between the two groups.

LEVEL OF EVIDENCE

II. Trial Registration Register: ClinicalTrials.gov, number: NCT05803681.

Development and validation of a machine learning model to predict imminent new vertebral fractures after vertebral augmentation

BACKGROUND

Accurately predicting the occurrence of imminent new vertebral fractures (NVFs) in patients with osteoporotic vertebral compression fractures (OVCFs) undergoing vertebral augmentation (VA) is challenging with yet no effective approach. This study aim to examine a machine learning model based on radiomics signature and clinical factors in predicting imminent new vertebral fractures after vertebral augmentation.

METHODS

A total of 235 eligible patients with OVCFs who underwent VA procedures were recruited from two independent institutions and categorized into three groups, including training set (n = 138), internal validation set (n = 59), and external validation set (n = 38). In the training set, radiomics features were computationally retrieved from L1 or adjacent vertebral body (T12 or L2) on T1-w MRI images, and a radiomics signature was constructed using the least absolute shrinkage and selection operator algorithm (LASSO). Predictive radiomics signature and clinical factors were fitted into two final prediction models using the random survival forest (RSF) algorithm or COX proportional hazard (CPH) analysis. Independent internal and external validation sets were used to validate the prediction models.

RESULTS

The two prediction models were integrated with radiomics signature and intravertebral cleft (IVC). The RSF model with C-indices of 0.763, 0.773, and 0.731 and time-dependent AUC (2 years) of 0.855, 0.907, and 0.839 (p < 0.001 for all) was found to be better predictive than the CPH model in training, internal and external validation sets. The RSF model provided better calibration, larger net benefits (determined by decision curve analysis), and lower prediction error (time-dependent brier score of 0.156, 0.151, and 0.146, respectively) than the CPH model.

CONCLUSIONS

The integrated RSF model showed the potential to predict imminent NVFs following vertebral augmentation, which will aid in postoperative follow-up and treatment.

Differentiation of acute and chronic vertebral compression fractures using conventional CT based on deep transfer learning features and hand-crafted radiomics features

BACKGROUND

We evaluated the diagnostic efficacy of deep learning radiomics (DLR) and hand-crafted radiomics (HCR) features in differentiating acute and chronic vertebral compression fractures (VCFs).

METHODS

A total of 365 patients with VCFs were retrospectively analysed based on their computed tomography (CT) scan data. All patients completed MRI examination within 2 weeks. There were 315 acute VCFs and 205 chronic VCFs. Deep transfer learning (DTL) features and HCR features were extracted from CT images of patients with VCFs using DLR and traditional radiomics, respectively, and feature fusion was performed to establish the least absolute shrinkage and selection operator. The MRI display of vertebral bone marrow oedema was used as the gold standard for acute VCF, and the model performance was evaluated using the receiver operating characteristic (ROC).To separately evaluate the effectiveness of DLR, traditional radiomics and feature fusion in the differential diagnosis of acute and chronic VCFs, we constructed a nomogram based on the clinical baseline data to visualize the classification evaluation. The predictive power of each model was compared using the Delong test, and the clinical value of the nomogram was evaluated using decision curve analysis (DCA).

RESULTS

Fifty DTL features were obtained from DLR, 41 HCR features were obtained from traditional radiomics, and 77 features fusion were obtained after feature screening and fusion of the two. The area under the curve (AUC) of the DLR model in the training cohort and test cohort were 0.992 (95% confidence interval (CI), 0.983-0.999) and 0.871 (95% CI, 0.805-0.938), respectively. While the AUCs of the conventional radiomics model in the training cohort and test cohort were 0.973 (95% CI, 0.955-0.990) and 0.854 (95% CI, 0.773-0.934), respectively. The AUCs of the features fusion model in the training cohort and test cohort were 0.997 (95% CI, 0.994-0.999) and 0.915 (95% CI, 0.855-0.974), respectively. The AUCs of nomogram constructed by the features fusion in combination with clinical baseline data were 0.998 (95% CI, 0.996-0.999) and 0.946 (95% CI, 0.906-0.987) in the training cohort and test cohort, respectively. The Delong test showed that the differences between the features fusion model and the nomogram in the training cohort and the test cohort were not statistically significant (P values were 0.794 and 0.668, respectively), and the differences in the other prediction models in the training cohort and the test cohort were statistically significant (P < 0.05). DCA showed that the nomogram had high clinical value.

CONCLUSION

The features fusion model can be used for the differential diagnosis of acute and chronic VCFs, and its differential diagnosis ability is improved when compared with that when either radiomics is used alone. At the same time, the nomogram has a high predictive value for acute and chronic VCFs and can be a potential decision-making tool to assist clinicians, especially when a patient is unable to undergo spinal MRI examination.

Patterns of Vertebral Bone Marrow Edema in the Normal Healing Process of Lumbar Interbody Fusion: Baseline Data for Diagnosis of Pathological Events

STUDY DESIGN

Retrospective investigation using a prospectively collected database.

OBJECTIVE

To examine the appearance and characteristics of vertebral bone marrow edema (BME) in the normal healing of lumbar interbody fusion.

SUMMARY OF BACKGROUND DATA

Although BME in pathological spinal conditions has been well-documented, the patterns and characteristics of BME in the normal healing process of spinal fusion remains unexplored.

MATERIALS AND METHODS

We reviewed imaging from 225 patients with normal healing following posterior lumbar interbody fusion or transforaminal lumbar interbody fusion. BME was identified on magnetic resonance imaging at the third postoperative week and categorized with respect to its appearance, including assessment of area and extension within the relevant vertebrae.

RESULTS

Three hundred eighty-nine of the 450 instrumented vertebrae (86.4%) displayed evidence BME. All instances of BME were associated with the area of contact with the endplate. The average extent of BME was 32.7±1.0%. BME within normal healing following interbody fusion could be categorized into four types: no edema (13.6%), anterior corner (36.6%), around-the-cage focal (48.0%), and diffuse (1.8%). Anterior corner BME was significantly associated with instances of single cage placement than in dual cages (42.6% vs. 24.7%, P =0.0002). Single cages had a significantly higher rate of BME than dual cages (92.0% vs. 75.3%, P <0.0001). The extent of BME was significantly greater in the single cage cohort (36.9% vs. 24.2% in dual cages, P <0.0001).

CONCLUSIONS

This serves as the first study demonstrating the patterns of BME associated with normal healing following lumbar interbody fusion procedures. Anterior corner BME and around-the-cage focal BME were the most common patterns encountered, with diffuse BME a relatively rare pattern. These findings might contribute to the better differentiation of postoperative pathological events from normal healing following lumbar interbody fusion.

LEVEL OF EVIDENCE

4.

Extent of bone marrow edema on dual-energy CT aids in differentiation of acute from post-acute fractures of lower legs

OBJECTIVES

Bone marrow edema (BME) from dual-energy CT is useful to direct attention to radiographically occult fractures. The aim was to characterize utility of BME of lower extremity (LE) fractures with the hypothesis that stabilized and post-acute fractures exhibit decreased extent and frequency of BME than non-stabilized and acute fractures, respectively.

METHODS

An IRB-approved retrospective review of known LE fractures. A total of 141 cases met inclusion criteria, including 82 fractures without splint/cast stabilization, and 59 cases with stabilization. Two readers independently recorded BME, and its multiplicity and area (mm²). A separate reader assessed fracture location, comminution, and chronicity. Wilcoxon rank sum test, multiple regression, intraclass correlation (ICC), kappa statistics, and chi-square tests were used.

RESULTS

BME was significantly larger in non-stabilized (859.3 mm² (420.6-1451.8)) than stabilized fractures (493.5 mm² (288.8-883.2)), p = .011). Comminuted (p = 0.006), non-stabilized (p = 0.0004), and acute fractures (p = 0.036) were all associated with larger BME area. BME presence had excellent results for both stabilized (Cohen's Kappa = 0.81) and non-stabilized fractures (Cohen's Kappa = 0.84). ICC for BME area showed excellent correlation for both stabilized (ICC = 0.78) and non-stabilized groups (ICC = 0.86). BME multiplicity showed excellent agreement for stabilized (ICC = 0.81) and good agreement for non-stabilized (ICC = 0.67) fractures. Lastly, stabilized cases showed increased multiplicity of BME compared to non-stabilized fractures (p < 0.001).

CONCLUSIONS

BME evaluation can assist in differentiation of acute versus post-acute fractures. Extent of BME is reduced with splint/cast stabilization, which may limit its accuracy in detection of lower extremity fractures.

KEY POINTS

• Evaluation of bone marrow edema on dual-energy CT aids in differentiation of acute versus post-acute fracture. • Bone marrow edema evaluation is limited in the setting of post-acute or stabilized fractures. • There is decreased frequency and extent of bone marrow edema in post-acute, non-comminuted, and stabilized fractures.

A Comparative Study of Bone Tissue Morphology and Bone Turnover Markers in Different Stages of Kümmell's Disease

Although the incidence of Kümmell's disease (KD) has increased significantly in recent years, its pathological mechanism is still unclear. The aim of this study is to investigate the histomorphological characteristics and the kinetics of bone turnover markers following KD. This study involves 82 patients with KD, and fasting blood samples were collected to detect the serum concentration of bone turnover markers. A transpedicular bone biopsy was performed to collect bone biopsy specimens during vertebroplasty surgery. According to Li's staging system for KD, all cases were divided into 3 stages. Comparisons of the 3 stages and their kinetics were conducted. 19 (23.2%) patients were classified as Stage I, 39 (47.5%) as Stage II, 24 (29.2%) as Stage III. Bone histomorphological analysis showed that the ratios of WBV and FV reached a peak value (14.23 ± 0.62 and 54.63% ± 3.52%; p = 0.001 and 0.001) at Stage I. The ratios of NBV remained low (4.81% ± 2.61%) in Stage I, but reached a peak value (18.50% ± 2.77%; p = 0.001) in Stage III. Bone metabolism index level showed that the serum concentration of OST and β-CTX continued to rise after fracture, reaching a peak value of (38.15 ± 3.84 and 1.31 ± 0.16 ng/Ml; p = 0.073 and 0.026), while PINP reached its valley value (48.57 ± 7.25 ng/Ml; p = 0.069) in Stage III. A significant and negative correlation was found between the ratio of β-CTX and EBV/TV (p= 0.0194, r = -0.2037), and FV/TV (p= 0.0001, r = -0.5368). At the same time, β-CTX had a positive significant correlation with the NBV/TV (p= 0.0001, r = 0.6218). Bone histomorphometric analysis and bone turnover markers showed that KD has a possibility of healing in the early stage.

Value of MRI in assessing back pain after thoracolumbar osteoporotic vertebral compression fractures and discussion on the underlying mechanisms by tissue biopsy

PURPOSE

The specific radiological feature of osteoporotic vertebral compression fractures (OVCFs) is bone marrow oedema (BME) on magnetic resonance imaging (MRI). However, the relationship between BME and back pain (BP) is unclear. We investigated the value of MRI in assessing BP and discussed the relevant mechanisms by tissue biopsy.

METHODS

One hundred nineteen patients with thoracolumbar OVCFs were included in this study. We divided all patients into two groups: the low-oedema group (BME ≤ 75%) and the high-oedema group (BME > 75%). To reduce the error generated in the acute phase of fracture, we separately analysed patients in phases I (within one month) and II (more than one month). We compared the differences between the groups using the Mann-Whitney U test and investigated the correlations using Spearman's correlation test.

RESULTS

The degree of BP was significantly correlated with BME (p < 0.001; p < 0.001) and fibrous tissue content (p = 0.006; p = 0.035) in both phases. Further, the fibrous tissue content in the low-oedema group (12.49 ± 7.37%; 15.25 ± 13.28%) was significantly lower than that in the high-oedema group (25.68 ± 20.39%, p = 0.014; 23.92 ± 14.61%, p = 0.022) in both phases. The lamellar bone content was significantly correlated with BP (p = 0.021) in phase II.

CONCLUSIONS

BME signals on MRI can accurately predict the degree of BP, and the main mechanisms are related to the stimulation of fibrous tissue.