Dynamic contrast-enhanced magnetic resonance imaging of osteoporotic vertebral fracture

Vertebral compression fractures managed with brace: risk factors for progression

PURPOSE

The aim of this study is to identify risk factors for vertebral compression fracture (VCF) progression in patients treated conservatively with a brace. Then, a case-control study was designed.

METHODS

All patients over 50 years old with diagnosis of thoracic or lumbar VCF (T5 to L5) in absence of underlying oncological process, treated conservatively with brace, and consecutively attended at our department from January 2017 to June 2021 were retrospectively selected for analysis. Patients missed for follow-up or dead during the first 3 months of follow-up were excluded.

RESULTS

Five hundred and eighty-two consecutive patients were recorded. Incomplete follow-up excluded 74 patients and other 19 died in the first three months after diagnosis, so 489 cases were finally analyzed. Median follow-up was 21 (IQR 13;30) weeks. Increased collapse of the vertebral body was found in 29.9% of VCFs with a median time to progression of 9 (IQR 7;13) weeks. Male gender (OR 1.6), type A3 fracture of the AOSpine classification (OR 2.7), thoracolumbar junction location (OR 1.7), and incorrect use of the brace (OR 3.5) were identified as independent risk factors for progression after multivariable analysis.

CONCLUSION

Male gender, type A3 fracture of the AOSpine classification, thoracolumbar junction location, and incorrect use of the brace were identified as independent risk factors for VCF progression, which resulted in worse pain control, when treated with brace. Thus, other treatments such as percutaneous vertebral augmentation could be considered to avoid progression in selected cases, since collapse rate has been demonstrated lower with these procedures.

Intravoxel Incoherent Motion Factors Affecting Collapse and Nonunion of Osteoporotic Vertebral Fracture

STUDY DESIGN

Longitudinal study.

OBJECTIVES

Intravoxel incoherent motion (IVIM), a magnetic resonance imaging (MRI) scanning technique that applies diffusion-weighted imaging (DWI), is effective for the quantitative assessment of malignant tumors of the vertebral bone. We hypothesized that IVIM parameters of vertebral bodies are associated with the prognosis of osteoporotic vertebral fracture (OVF). We aimed to explore the relationships between IVIM parameters for vertebral collapse and non-union after OVF and calculate the cut-off values of these parameters for vertebral collapse and non-union.

METHODS

A total of 150 patients with acute OVF (150 women; mean age: 79.1 ± 7.4 years) were included and treated conservatively with bracing. MRI was performed at the time of injury. IVIM parameters, such as apparent diffusion coefficient (ADC), molecular diffusion coefficient (D), and perfusion-related diffusion (D*) were recorded. The patients were classified into 3 groups: low-collapse (height loss of ≤50%), high-collapse (height loss of >50%), and non-union. We compared ADC, D, and D* among the low-collapse, high-collapse, and non-union groups and performed a receiver operating characteristic (ROC) curve analysis to determine the boundary values of the high-collapse and non-union groups.

RESULTS

The low-collapse, high-collapse, and non-union groups had no significant differences in ADC and D. However, D* differed significantly among the 3 groups. ROC analysis revealed cut-off values of 19.0 × 10-3 mm2/s and 12.3 × 10-3 mm2/s for the high-collapse and non-union groups, respectively.

CONCLUSIONS

D* is a significant prognostic indicator for high-collapse and non-union groups with OVF. This suggests that D* should be considered when assessing OVF.

Prospective Study to Identify the Clinical and Radiologic Factors Predictive of Pseudarthrosis Development in Patients with Osteoporotic Vertebral Fractures

BACKGROUND

Although most osteoporotic vertebral fractures (OVFs) heal conservatively, the most crucial undesirable outcome of conservative treatment is the failure to unite. There is paucity of literature on prevalence and risk factors of pseudarthrosis.

METHODS

A prospective study involving patients (aged ≥50 years) undergoing conservative treatment of osteoporotic thoracic/lumbar fractures without neurodeficits was performed. Patients were followed for a minimum of 6 months and classified into 3 groups based on fracture healing: group 1, healing without collapse; group 2, healing with collapse; and group 3, pseudarthrosis. An assessment of all clinicoradiologic parameters at the time of injury and at each follow-up was performed and compared among patients belonging to the groups.

RESULTS

A total of 77 patients (90 fractures) were studied. Sixty-six (73.3%), 16 (17.8%), and 28 (8.9%) fractures were classified under groups 1, 2, and 3, respectively. Mean ages in groups 1, 2, and 3 were 67.9 ± 9.1, 70.4 ± 7.6 and 72.3 ± 7.9 years (P = 0.08). Sex distribution was 62:15 (female/male). Seventy-three fractures (81.1%) occurred at the thoracolumbar junction. Stiff spine, ambulatory status, comorbidities, bone mineral density, and injury level were not associated with pseudarthrosis/collapse (P > 0.05). Male sex was associated with pseudarthrosis (P = 0.03). Based on regression analysis, initial vertebral height loss (radiography; P = 0.028), segmental Cobb (radiography; P = 0.019), vertebral comminution (computed tomography; P = 0.032), posterior ligamentous complex injury (magnetic resonance imaging; P = 0.048), and marrow change pattern (T2-weighted magnetic resonance imaging, Kanchiku classification; P = 0.037) were correlated with poorer outcome. Patients with pseudarthrosis had higher visual analog scale score (P = 0.04; final follow-up).

CONCLUSIONS

Of OVFs, 8.9% developed pseudarthrosis. Male sex, severity of postinjury vertebral deformation (vertebral loss, kyphosis, comminution, and marrow changes) and presence of posterior ligamentous complex injury are risk factors for pseudarthrosis.

Imaging of Bone Marrow: From Science to Practice

The study of the bone marrow may pose important challenges, due to its changing features over the life span, metabolic stress, and in cases of disease or treatment. Bone marrow adipocytes serve as storage tissue, but they also have endocrine and paracrine functions, contributing to local and systemic metabolism.Among different techniques, magnetic resonance (MR) has the benefit of imaging bone marrow directly. The use of advanced MR techniques for bone marrow study has rapidly found clinical applications. Beyond the clinical uses, it has opened up pathways to assess and quantify bone marrow components, establishing the groundwork for further study of its implications in physiologic and pathologic conditions.We summarize the features of the bone marrow as an organ, address the different modalities available for its study, with a special focus on MR advanced techniques and their addition to analysis in recent years, and review some of the challenges in interpreting the appearance of bone marrow.

Quantifying lumbar vertebral perfusion by a Tofts model on DCE-MRI using segmental versus aortic arterial input function

The purpose of this study was to investigate the influence of arterial input function (AIF) selection on the quantification of vertebral perfusion using axial dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). In this study, axial DCE-MRI was performed on 2 vertebrae in each of eight healthy volunteers (mean age, 36.9 years; 5 men) using a 1.5-T scanner. The pharmacokinetic parameters K^trans, v_e, and v_p, derived using a Tofts model on axial DCE-MRI of the lumbar vertebrae, were evaluated using various AIFs: the population-based aortic AIF (AIF_PA), a patient-specific aortic AIF (AIF_A) and a patient-specific segmental arterial AIF (AIF_SA). Additionally, peaks and delay times were changed to simulate the effects of various AIFs on the calculation of perfusion parameters. Nonparametric analyses including the Wilcoxon signed rank test and the Kruskal–Wallis test with a Dunn–Bonferroni post hoc analysis were performed. In simulation, K^trans and v_e increased as the peak in the AIF decreased, but v_p increased when delay time in the AIF increased. In humans, the estimated K^trans and v_e were significantly smaller using AIF_A compared to AIF_SA no matter the computation style (pixel-wise or region-of-interest based). Both these perfusion parameters were significantly greater using AIF_SA compared to AIF_A.

Use of proton density fat fraction MRI to predict the radiographic progression of osteoporotic vertebral compression fracture

OBJECTIVE

This study evaluated the diagnostic performance of the proton density fat fraction (PDFF) in predicting the progression of osteoporotic vertebral compression fractures (OVCFs).

METHODS

The cohort in this retrospective study consisted of 48 patients with OVCFs who underwent spine MRI that included PDFF between December 2016 and June 2018. The patients were divided into two groups (with versus without OVCF progression, based on the radiographic results obtained at the 6-month follow-up examination). Two musculoskeletal radiologists independently calculated the PDFF of the fracture and the PDFF ratio (fracture PDFF/normal vertebrae PDFF) using regions of interest. The mean values of these parameters were compared between the two groups, and the receiver operating characteristic curves were analysed.

RESULTS

The mean age was significantly higher in the group with OVCF progression (71.6 ± 8.4 years) than in the group without (64.8 ± 10.5 years) (p = 0.018). According to reader 1, the PDFF ratio was significantly lower in the group with OVCF progression versus that without OVCF progression (0.38 ± 0.13 vs 0.51 ± 0.20; p = 0.009), whereas the difference in the PDFF itself was not statistically significant. The PDFF ratio [area under the curve (AUC) = 0.723; 95% confidence interval (CI), 0.575-0.842] had a larger AUC than did the PDFF (AUC = 0.667; 95% CI, 0.516-0.796). The optimal cut-off value of the PDFF ratio for predicting OVCF progression was 0.42; this threshold corresponded to sensitivity, specificity, and accuracy values of 84.0%, 60.9%, and 72.9%, respectively.

CONCLUSION

The age and PDFF ratio can be used to predict OVCF progression.

KEY POINTS

• Chemical shift-encoded magnetic resonance imaging provides quantitative parameters for predicting OVCF progression. • The PDFF ratio is significantly lower in patients with OVCF progression. • The PDFF ratio is superior to the PDFF for predicting OVCF progression.

Changes in magnetic resonance imaging signal intensity in predicting complications during acute phase osteoporotic vertebral fractures

Purpose

To demonstrate prediction of complications in osteoporotic vertebral fractures with magnetic resonance imaging (MRI) changes over time.

Methods

MRI signal intensities in osteoporotic vertebral fractures were investigated according to the interval between onset and imaging as follows: 0-10 days (early), 11-20 days (middle), and 21-30 days (later).

Results

The diffuse low pattern rates were 52%, 84%, and 95% and 20%, 24%, and 52% in the early, middle, and later periods on T1-WI and T2-WI, respectively.

Conclusions

The diffuse low pattern increased with time. The MRI prediction of complications depends on the time phase.

Usefulness of Fat Suppression Magnetic Resonance Imaging of Osteoporotic Vertebral Fractures in Preventing Subsequent Fractures After Kyphoplasty

BACKGROUND

Preoperative magnetic resonance imaging with fat suppression (FS-MRI) is useful to detect bone marrow edema in osteoporotic vertebral fractures (OVFs) and thus can improve diagnostic accuracy and influence surgical strategy for percutaneous augmentation. The role of preoperative FS-MRI in preventing subsequent fractures after balloon kyphoplasty has not been investigated in initially subclinical fractures or fractures without obvious morphologic changes.

METHODS

From January 2010 to December 2017, 214 consecutive patients underwent balloon kyphoplasty for painful OVFs. We defined 2 groups based on preoperative imaging (100 patients had preoperative FS-MRI and 114 patients had no MRI) and then compared baseline and surgical characteristics. The primary end point was incidence of subsequent fractures within 12 months after treatment.

RESULTS

The 214 patients underwent kyphoplasty of 414 vertebrae. Comparing FS-MRI with no-MRI groups, spontaneous fractures occurred significantly more (58% vs. 26.3%; P < 0.001) and fractures were more often multilevel (≥ 4 levels) (15% vs. 2.6%; P = 0.001), respectively. Overall incidence of subsequent vertebral fractures was 25.7% (32% in FS-MRI, 20.2% in no-MRI groups; P = 0.048). Average time to diagnosis of subsequent fractures did not differ between the 2 groups (9.3 FS-MRI vs. 11.5 weeks no-MRI; P = 0.411). Age ≥80 years at the time of balloon kyphoplasty was associated with a higher odds ratio (2.3) for subsequent fractures within 12 months (P = 0.039).

CONCLUSIONS

Surgical treatment according to preoperative FS-MRI did not reduce occurrence of subsequent OVFs and did not prolong fracture-free intervals within 12 months after kyphoplasty.

The Prognostic Significance of Pedicle Enhancement from Contrast-enhanced MRI for the Further Collapse in Osteoporotic Vertebral Compression Fractures

STUDY DESIGN

A retrospective observational study.

OBJECTIVE

The aim of this study was to investigate the prognostic significance of contrast-enhanced magnetic resonance imaging (MRI) for detecting pedicle enhancement and predicting future collapse in patients with acute benign osteoporotic vertebral compression fracture (OVCF).

SUMMARY OF BACKGROUND DATA

Traditional morphological classification regarding compression versus burst fractures cannot accurately anticipate the prognosis of further collapse. Identifying subgroups with a higher risk for further collapse may be beneficial in determining the treatment modality, which should be decided immediately after the injury.

METHODS

One hundred fourteen patients with benign OVCFs who, at the onset, underwent contrast-enhanced spine MRI between 2003 and 2016 were retrospectively analyzed. Patients were recruited on the basis of predefined inclusion and exclusion criteria. The primary outcome was the compression progression rate; other potential variables included demographic and clinical characteristics, initial compression rates, and kyphotic angles. In addition, other structural abnormalities on MRI were assessed. The compression progression rates were compared according to pedicle enhancement, and the prognostic significance of pedicle enhancement for further collapse were analyzed.

RESULTS

Further compression progression rates were significantly higher in the pedicle-enhanced (PE) group than in the nonenhanced (NE) group. Multivariate logistic analysis revealed that pedicle enhancement may be associated with further compression progression ≥10%. The vertebral augmentation (VAG) protective effect against collapse was only significant within the PE group, while bone densitometry and patients' mobility were significant only within the NE group. The log-rank test revealed a statistically significant difference in the rates of further collapse ≥10% during the 1 year between the groups.

CONCLUSION

Sign of pedicle enhancement is a potential risk factor for further compression progression. Contrast-enhanced MRI should be performed at the onset to better determine the future risk of collapse and to choose a better treatment modality for benign OVCF patients.

LEVEL OF EVIDENCE

3.

Quantitative imaging methods in osteoporosis

Osteoporosis is characterized by a decreased bone mass and quality resulting in an increased fracture risk. Quantitative imaging methods are critical in the diagnosis and follow-up of treatment effects in osteoporosis. Prior radiographic vertebral fractures and bone mineral density (BMD) as a quantitative parameter derived from dual-energy X-ray absorptiometry (DXA) are among the strongest known predictors of future osteoporotic fractures. Therefore, current clinical decision making relies heavily on accurate assessment of these imaging features. Further, novel quantitative techniques are being developed to appraise additional characteristics of osteoporosis including three-dimensional bone architecture with quantitative computed tomography (QCT). Dedicated high-resolution (HR) CT equipment is available to enhance image quality. At the other end of the spectrum, by utilizing post-processing techniques such as the trabecular bone score (TBS) information on three-dimensional architecture can be derived from DXA images. Further developments in magnetic resonance imaging (MRI) seem promising to not only capture bone micro-architecture but also characterize processes at the molecular level. This review provides an overview of various quantitative imaging techniques based on different radiological modalities utilized in clinical osteoporosis care and research.

CT Perfusion in Spinal Disease: An Adjunct Tool to Vertebral Body Biopsy

Routine diagnostic techniques are inadequate for diagnosis of spinal diseases. The purpose of this study was to determine whether CT perfusion can differentiate inflammatory diseases like tuberculosis from neoplastic diseases of spine. Thirty-two patients with vertebral body lesions associated with paraspinal mass underwent CT guided bone biopsy and histopathological evaluation. CT perfusion was done in all patients before doing biopsy. Perfusion parameters like blood volume (BV), blood flow (BF) and time to peak (TTP) were calculated and correlated with histopathology. Statistical analysis was done using Mann-Whitney test. p value <0.05 was considered significant. Of 32 cases, 20 had tuberculous osteomyelitis and 12 neoplastic disease (seven metastasis, three plasmacytoma, one each lymphoma and chordoma). Mean rBF was [inflammatory lesions, 1.459 and neoplastic lesions, 18.080 (p<0.000). Mean rBV was (inflammatory disease, 2.8589 and neoplastic lesions, 12.2133 (p<0 .000)). Mean rTTP was [inflammatory pathology, 1.041 and neoplastic pathology, 0.703(p<0.079)]. This shows the deconvolution-based CTP technique's potential for noninvasive diagnosis of at least all inflammatory lesions affecting the spine that are associated with paraspinal mass. Validation of the use of deconvolution CTP parameters for differentiation of inflammatory from neoplastic pathology may permit this technique to be used as an adjunct tool when biopsy when routine imaging findings are inconclusive.

New advances in imaging osteoporosis and its complications

Tremendous advances have been made over the past several decades in assessing osteoporosis and its complications. High resolution imaging combined with sophisticated computational techniques now provide a detailed analysis of bone structure and a much more accurate prediction of bone strength. These techniques have shown how different mechanisms of age-related bone weakening exist in males and females. Limitations peculiar to these more advanced imaging techniques currently hinder their adoption into mainstream clinical practice. As such, the ultimate quest remains a readily available, safe, high resolution technique capable of fully predicting bone strength, capable of showing how bone strength is faltering and precisely monitoring treatment effect. Whether this technique will be based on acquisition of spine/hip data or data obtained at peripheral sites reflective of changes happening in the spine and hip regions is still not clear. In the meantime, mainstream imaging will continue to improve the detection of osteoporosis related insufficiency fracture in the clinical setting. We, as clinicians, should aim to increase awareness of this fracture type both as a frequent and varied source of pain in patients with osteoporosis and as the ultimate marker of severely impaired bone strength.

MRI of spinal bone marrow: part I, techniques and normal age-related appearances

OBJECTIVE

This article reviews MRI protocols, including routine and nonroutine pulse sequences as well as the normal MRI appearance of spinal marrow and expected age-related changes.

CONCLUSION

Routine MRI of the spine provides useful evaluation of the spinal bone marrow, but nonroutine MRI pulse sequences are increasingly being used to evaluate bone marrow pathology. An understanding of MRI pulse sequences and the normal and age-related appearances of bone marrow is important for the practicing radiologist.

Dynamic contrast-enhanced magnetic resonance imaging for evaluating intraosseous cleft formation in patients with osteoporotic vertebral compression fractures before vertebroplasty

STUDY DESIGN

A prospective trial of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in patients with osteoporotic vertebral compression fracture (VCF).

OBJECTIVE

To investigate the relationship between intraosseous clefts and bone marrow perfusion using DCE-MRI in patients with osteoporotic VCF before vertebroplasty.

SUMMARY OF BACKGROUND DATA

The nonhealing cleft may be responsible for persistent pain and progressive vertebral collapse after acute injury. If localized kyphosis increased, there is risk of neuropathy appearing as a complication. Even after receiving vertebroplasty, it was reported to be at increased risk for subsequent cemented vertebral refracture and new adjacent vertebral fractures. DCE -MRI has been used for the evaluation of bone marrow perfusion. However, there are few reports on the evaluation of osteoporotic VCF and intraosseous cleft formation.

MATERIALS

Forty subjects referred for evaluation of VCF underwent DCE-MRI. Bone marrow perfusion, as measured using the DCE-MRI time-intensity curve from a noninjured vertebrae was developed using two distinct parameters including peak enhancement ratio and enhancement slope. The ratio of the well-enhanced and the poorly enhanced zone of each injured vertebra were calculated. Multiple logistic regression analysis was used to evaluate the relationships between baseline clinical factors, parameters of DCE-MRI and presence or absence of intraosseous clefts.

RESULTS

Twenty-nine injured vertebrae (72%) had intraosseous clefts. Lower PER of the noninjured vertebrae was associated with higher poorly enhanced zone ratio of the injured vertebrae (γ = -0.362, P = 0.017). Multivariate logistic regression analysis identified only lower PER (hazard ratio, 0.000; 95% confidence interval, 0.000-0.096; P = 0.009) was associated with the presence of intraosseous clefts. A peak enhancement ratio value less than 0.57 had a sensitivity of 80% and specificity of 90% for predicting intraosseous clefts.

CONCLUSION

In patients with osteoporotic VCF before vertebroplasty, decreased bone marrow perfusion, as measured by DCE-MRI, was associated with intraosseous cleft formation.

The impact of preoperative magnetic resonance images on outcome of cemented vertebrae

Refracture of cemented vertebrae is often seen after percutaneous vertebroplasty. The purpose of this prospective study was to evaluate pre-procedural magnetic resonance images (MRI) for the prediction of further collapse and vertebral height loss after vertebroplasty. This study included 81 consecutive patients (73 women and 8 men) with osteoporotic compression fractures. MR studies were performed 1-5 days before vertebroplasty. Patients were followed to evaluate refracture for a minimum of 6 months after treatment. Cox proportional hazards model was used to evaluate relationships between clinical data, covariates on pre-procedural MRI, and the presence of cemented vertebrae refracture. The mean refracture rate was estimated with the Kaplan-Meier method. After a mean follow-up of 23.0 ± 8.2 months, 46 cemented vertebrae (57%) experienced refracture, and the mean loss of anterior vertebral height was 11.3%. The 1-year refracture rate after vertebroplasty was 7%, and rapid increased to 76% in the third year. Cox proportional analysis showed that any 1% decrease in signal intensity on T2-weighted images of the injured vertebra will increase the refracture rate by 0.74% (OR = 0.26, 95% CI 0.08-0.81, p = 0.02), and a 1% increase in the poorly enhanced volume ratio will increase the refracture rate by 4.3% (OR = 5.32, 95% CI 1.22-23.14, p = 0.03). Quantitative pre-procedural MRI appears to be useful in exploring vertebrae with poor bone marrow integrity, which effectively predicts the subsequent refracture of cemented vertebra.

The prognosis for pain, disability, activities of daily living and quality of life after an acute osteoporotic vertebral body fracture: its relation to fracture level, type of fracture and grade of fracture deformation

The level of the acute osteoporotic vertebral fracture, fracture type and grade of fracture deformation were determined in 107 consecutive patients and related to pain, disability, activities of daily living (ADL) and quality of life (QoL) after 3 weeks, 3, 6 and 12 months. Two-thirds of the fractured patients were women and with a similar average age, around 75 years, as the men. Fifty-eight of the acute fractures were located in the thoracic spine and 49 in the lumbar spine and predominantly at the Th12 and L1 levels. Sixty-nine percent of the fractures were wedge, 19% concave and 12% crush fractures. There were 22 mildly, 50 moderately and 35 severely deformed vertebrae. The grade of fracture deformation was not related to gender, age or fracture location. Severely deformed vertebrae predominantly (92%) occurred among the crush fracture type. One year after the fracture, irrespective of fracture level, fracture type or grade of fracture deformation, 4/5 still had pronounced pain and deteriorated QoL. Initial severe fracture deformation by far was the worst prognostic factor for severe lasting pain and disability, and deterioration of ADL and QoL. Factors like fracture level, lumbar fractures tended to improve steadily while thoracic deteriorated, type of fracture, the wedge and concave resulting in less pain and better QoL than the crush fracture type and gender influenced to a lesser extent the outcomes during the year after the acute fracture.

The usefulness of CT perfusion in differentiation between neoplastic and tuberculous disease of the spine

INTRODUCTION

Routine diagnostic techniques are not sufficient to confidently differentiate diseases of the axial skeleton. Purpose of study was to determine whether CT perfusion (CTP) can differentiate inflammatory diseases like tuberculosis from neoplastic diseases of spine.

METHODS

Fifty-one patients with vertebrdraft%freshal body lesions associated with paraspinal mass underwent CT guided bone biopsy and histopathological evaluation. CTP was done before doing bone biopsy. Perfusion parameters like blood volume (BV), blood flow (BF), and time to peak (TTP) were calculated. Values are correlated with histopathological report of bone biopsy. Statistical analysis was done using Mann-Whitney test. P value < .05 was considered significant.

RESULTS

Of 51, 32 had infective osteomyelitis and 19 neoplastic disease (9 metastasis, 5 plasmacytoma, 4 lymphoma and 1 chordoma. Mean rBF was [inflammatory lesions, 1.79 and neoplastic lesions, 9.42 (P < .000)]. Mean rBV was [inflammatory disease, 1.63 and neoplastic lesions, 9.37 (P < .000)].

CONCLUSION

CTP technique has potential for differentiating inflammatory from neoplastic lesions affecting spine associated with paraspinal mass noninvasively.