Diagnostic Accuracy of Quantitative Imaging Biomarkers in the Differentiation of Benign and Malignant Vertebral Lesions : Combination of Diffusion-Weighted and Proton Density Fat Fraction Spine MRI

Comparative analysis of MRI-based VBQ and EBQ score for predicting cage subsidence in PILF surgery

BACKGROUND CONTEXT

As lumbar degenerative diseases become more prevalent in an aging population, there is an increasing demand for surgical interventions, such as posterior lumbar interbody fusion (PLIF). However, cage subsidence (CS), observed in 23.9-54% of cases postoperatively, remains a significant complication. Several factors, including age, bone quality, and endplate damage, contribute to the risk of CS, with bone quality being among the most critical determinants. Although DEXA and QCT are widely employed to assess bone density, their routine use in preoperative evaluations is restricted by cost considerations and radiation exposure. Recent studies suggest that MRI-based vertebral body quality (VBQ) and endplate bone quality (EBQ) score offer a viable, non-invasive alternative for evaluating bone quality; however, there is limited research comparing their predictive value for CS.

METHODS

In this retrospective study, 165 patients undergoing single-level PLIF surgery were included. MRI-based VBQ and EBQ score were calculated using T1-weighted images, and preoperative QCT was employed as a clinical standard. Cage subsidence was assessed based on postoperative imaging at 12-month follow-up. Statistical analyses, including t-tests, chi-square tests, and ROC curve analyses, were used to evaluate the predictive accuracy of VBQ and EBQ for CS.

RESULTS

The study's findings demonstrated that both VBQ and EBQ scores were significantly correlated with QCT measurements, thereby validating their utility as indicators of bone quality. ROC analysis revealed that VBQ had superior predictive value for CS (AUC = 0.814) compared to EBQ (AUC = 0.719), with both scores demonstrating significant clinical utility in identifying patients at risk for CS. Notably, VBQ exhibited a stronger correlation with preoperative clinical outcomes compared to EBQ, underscoring its greater reliability as a predictor.

CONCLUSIONS

This study highlights the effectiveness of MRI-based VBQ and EBQ score as practical, non-invasive tools for assessing bone quality preoperatively, with VBQ demonstrating superior predictive performance for CS risk. The findings underscore the potential of integrating these MRI-based assessments into routine preoperative planning to improve patient outcomes and minimize complications associated with PLIF surgery.

Impact of fat content on lumbar spine DWI performance: A sex-based comparative study

Purpose

Sex-based differences in lumbar spine's fat content in adults are minimal, but significant variations exist in diffusion-weighted imaging (DWI) signal characteristics. This study aimed to investigate fat content's impact on DWI performance in lumbar spine and potential sex differences.

Methods

A retrospective analysis was conducted on upper abdominal MRI examinations in asymptomatic adult. The lumbar 1 vertebral apparent diffusion coefficient (ADC) values and fat fraction were measured. Using DWI images (b = 800 s/mm2), the lumbar 1 vertebral signal was categorized into high and iso-low signal groups. A univariate and multivariate analysis was conducted to investigate the influence of fat fraction on DWI performance. Finally, the participants were divided into three groups to analyze sex differences in the effect of fat content on DWI performance.

Results

202 subjects, 99 men were included. Fat content significantly influenced lumbar spine DWI signal in both sexes (p < 0.05). The effect on ADC values was significant only in women (p < 0.001). Women demonstrated a significantly higher proportion of high DWI signal than men in the low (p = 0.002) and middle (p = 0.012) fat content groups. Additionally, women had higher ADC values in the low fat group (p = 0.004) but lower values in the high fat group (p = 0.004).

Conclusion

Fat content significantly impacts the DWI signal of lumbar spine, with a slight sex difference observed. These sex differences suggest that DWI signals may provide valuable information about the bone marrow beyond fat content.

Assessment of chemical-shift and diffusion-weighted magnetic resonance imaging in differentiating malignant and benign vertebral lesions in oncologic patients. A single institution experience

BACKGROUND

To analyze the contribution of two non-standard magnetic resonance imaging (MRI) techniques the chemical-shift image (CSI), and diffusion-weighted imaging (DWI) in distinguishing malignant and benign vertebral bone marrow lesions (VBMLs).

PATIENTS AND METHODS

Conventional spine MRI protocol, followed by CSI and DWI was performed with a 1.5 T system on 102 oncologic patients between January 2020 and December 2023. From the identified 325 VBMLs, 102 representative lesions (one per patient) were selected. VBMLs were divided into malignant (n = 74) and benign (n = 28) based on histopathology, or imaging follow-up. The quantitative parameters for VBMLs assessment were signal intensity ratio (SIR) derived from CSI and apparent diffusion coefficient (ADC) derived from DWI.

RESULTS

The malignant VBMLs had significantly higher SIR values (p < 0.05) and lower ADC values compared to benign VBMLs (p < 0.05). The area under the curve (AUC) was 0.953 (p < 0.001) for SIR, and 0.894 for ADC (p < 0.001) (cut-off at > 0.82, and ≤ 1.57x10-3 mm2/s, respectively). The sensitivity and specificity for SIR were 93.6%, and 88.5%, while for ADC were 88.2% and 92.3% (respectively). The combined use of SIR and ADC improved the diagnostic accuracy to AUC of 0.988 (p < 0.001, cut-off at > 0.19), sensitivity, and specificity of 100.0% and 90.9% (respectively).

CONCLUSIONS

Quantitative parameters, SIR and ADC, derived from two non-standard MRI techniques, CSI, and DWI, showed diagnostic strength in differentiating malignant and benign VBMLs. Combining both methods can further enhance the diagnostic performance and accuracy of spine MRI in clinical practice.

Efficacy of fat quantification methods used in MRI to distinguish between normal, benign, and malignant bone marrow pathologies in children

BACKGROUND

Fat quantification methods in magnetic resonance imaging (MRI) have been studied to differentiate bone marrow pathologies in adult patients; however, scarce literature is available in pediatric patients.

PURPOSE

To evaluate the efficacy of the T1 signal intensity value (T1-SIV), out-of-phase/in-phase signal ratio (OP/IP SR), and fat fraction (FF) to differentiate between normal, benign, and malignant pathological processes.

MATERIAL AND METHODS

A total of 48 pediatric patients with lumbar and pelvic MRI were classified into three groups according to bone marrow pathology (group 1, normal; group 2, benign pathology/reconversion; group 3, malignant). The efficacy of T1-SIV, OP/IP SR, and FF values in differentiating these pathologies was evaluated using Kruskal-Wallis or analysis of variance and followed by Bonferroni or Dunn-Bonferroni tests. Cutoff values for malignant infiltration were defined using ROC analysis.

RESULTS

Although these values were significantly different in all three groups (P = 0.001-0.008), this difference was not sufficient to discriminate between all groups. Subgroup analyses showed significant differences in T1-SIV between groups 1-3, in OP/IP SR between groups 1-3, 2-3, and 1-2, in FF between groups 1-2 and 1-3 in various regions (P = 0.001-0.049). Cutoff values had a sensitivity and specificity of 90%-100% for OP/IP SR and FF.

CONCLUSION

T1-SIV, OP/IP SR, and FF may potentially distinguish normal from pathological bone marrow. OP/IP SR and FF values detected malignant infiltration with high sensitivity and specificity in this study. However, only OP/IP SR may significantly differentiate benign and malignant bone marrow pathologies which needs to be confirmed in the future study with a larger patient population.

The role of diffusion-weighted MRI in the accurate diagnosis of vertebral compression fractures: A comparative study

INTRODUCTION

Accurately distinguishing between benign and malignant vertebral compression fractures is crucial for clinical management. This study evaluated the predictive accuracy of diffusion-weighted imaging (DWI) in differentiating the cause of vertebral fractures using MRI.

METHODS

A longitudinal cross-over study was conducted at Jinnah Postgraduate Medical Centre (JPMC) Karachi from July 2018 to January 2021. Patients with vertebral compression fractures underwent T1-weighted, T2-weighted, and DWI imaging with ADC mapping on a 1.5 T MRI scanner. Imaging findings were compared with histopathologic results and clinical follow-up. Sensitivity, specificity, and ROC curve analyses were performed.

RESULTS

The study enrolled 303 patients with a mean age of 43.6 ± 10.9 years, of whom 118 were male. DWI demonstrated high accuracy in predicting the cause of vertebral compression fractures, with a sensitivity of 96.2 %, a specificity of 76.2 %, and an area under the ROC curve of 0.857. The optimal ADC cut-off value was 0.82 × 10˄-3 mm˄2/s, which yielded a positive predictive value of 79.7 % and a negative predictive value of 95.4 %.

CONCLUSIONS

DWI is a safe and non-invasive imaging modality with excellent predictive accuracy in differentiating between benign and malignant vertebral compression fractures. Iso- or hypointensity of collapsed vertebral bodies on DWI suggests a benign lesion, while T2-weighted hyperintensity is highly indicative of malignancy. Low signal on ADC is also highly indicative of malignant vertebral fractures. Incorporating DWI improves accuracy in assessing vertebral lesions, especially when standard sequences are inconclusive.

IMPLICATIONS FOR PRACTICE

DWI revolutionizes vertebral compression fracture diagnosis, distinguishing between benign and malignant cases. This precision guides treatment decisions, minimizing the necessity for invasive procedures like biopsy. As a safe and reliable imaging method, DWI elevates patient care, ensuring accurate diagnostics and improved outcomes.

Fat quantification: Imaging methods and clinical applications in cancer

Recently, the study of the relationship between lipid metabolism and cancer has evolved. The characteristics of intratumoral and peritumoral fat are distinct and changeable during cancer development. Subcutaneous and visceral adipose tissue are also associated with cancer prognosis. In non-invasive imaging, fat quantification parameters such as controlled attenuation parameter, fat volume fraction, and proton density fat fraction from different imaging methods complement conventional images by providing concrete fat information. Therefore, measuring the changes of fat content for further understanding of cancer characteristics has been applied in both research and clinical settings. In this review, the authors summarize imaging advances in fat quantification and highlight their clinical applications in cancer precaution, auxiliary diagnosis and classification, therapy response monitoring, and prognosis.

Imaging of bone marrow pitfalls with emphasis on MRI

Normal marrow contains both hematopoietic/red and fatty/yellow marrow with a predictable pattern of conversion and skeletal distribution on MRI. Many variations in normal bone marrow signal and appearances are apparent and the reporting radiologist must differentiate these from other non-neoplastic, benign or neoplastic processes. The advent of chemical shift imaging has helped in characterising and differentiating more focal heterogeneous areas of red marrow from marrow infiltration. This review aims to cover the MRI appearances of normal marrow, its evolution with age, marrow reconversion, variations of normal marrow signal, causes of oedema-like marrow signal, and some common non-neoplastic entities, which may mimic marrow neoplasms.

Finite Element Analysis of Osteoporotic and Osteoblastic Vertebrae and Its Association With the Proton Density Fat Fraction From Chemical Shift Encoding-Based Water-Fat MRI - A Preliminary Study

PURPOSE

Osteoporosis is prevalent and entails alterations of vertebral bone and marrow. Yet, the spine is also a common site of metastatic spread. Parameters that can be non-invasively measured and could capture these alterations are the volumetric bone mineral density (vBMD), proton density fat fraction (PDFF) as an estimate of relative fat content, and failure displacement and load from finite element analysis (FEA) for assessment of bone strength. This study's purpose was to investigate if osteoporotic and osteoblastic metastatic changes in lumbar vertebrae can be differentiated based on the abovementioned parameters (vBMD, PDFF, and measures from FEA), and how these parameters correlate with each other.

MATERIALS AND METHODS

Seven patients (3 females, median age: 77.5 years) who received 3-Tesla magnetic resonance imaging (MRI) and multi-detector computed tomography (CT) of the lumbar spine and were diagnosed with either osteoporosis (4 patients) or diffuse osteoblastic metastases (3 patients) were included. Chemical shift encoding-based water-fat MRI (CSE-MRI) was used to extract the PDFF, while vBMD was extracted after automated vertebral body segmentation using CT. Segmentation masks were used for FEA-based failure displacement and failure load calculations. Failure displacement, failure load, and PDFF were compared between patients with osteoporotic vertebrae versus patients with osteoblastic metastases, considering non-fractured vertebrae (L1-L4). Associations between those parameters were assessed using Spearman correlation.

RESULTS

Median vBMD was 59.3 mg/cm³ in osteoporotic patients. Median PDFF was lower in the metastatic compared to the osteoporotic patients (11.9% vs. 43.8%, p=0.032). Median failure displacement and failure load were significantly higher in metastatic compared to osteoporotic patients (0.874 mm vs. 0.348 mm, 29,589 N vs. 3,095 N, p=0.034 each). A strong correlation was noted between PDFF and failure displacement (rho -0.679, p=0.094). A very strong correlation was noted between PDFF and failure load (rho -0.893, p=0.007).

CONCLUSION

PDFF as well as failure displacement and load allowed to distinguish osteoporotic from diffuse osteoblastic vertebrae. Our findings further show strong associations between PDFF and failure displacement and load, thus may indicate complimentary pathophysiological associations derived from two non-invasive techniques (CSE-MRI and CT) that inherently measure different properties of vertebral bone and marrow.

Proton Density Fat Fraction Spine MRI for Differentiation of Erosive Vertebral Endplate Degeneration and Infectious Spondylitis

Vertebral Modic type 1 (MT1) degeneration may mimic infectious disease on conventional spine magnetic resonance imaging (MRI), potentially leading to additional costly and invasive investigations. This study evaluated the diagnostic performance of the proton density fat fraction (PDFF) for distinguishing MT1 degenerative endplate changes from infectious spondylitis. A total of 31 and 22 patients with equivocal diagnosis of MT1 degeneration and infectious spondylitis, respectively, were retrospectively enrolled in this IRB-approved retrospective study and examined with a chemical-shift encoding (CSE)-based water-fat 3D six-echo modified Dixon sequence in addition to routine clinical spine MRI. Diagnostic reference standard was established according to histopathology or clinical and imaging follow-up. Intravertebral PDFF [%] and PDFFratio (i.e., vertebral endplate PDFF/normal vertebrae PDFF) were calculated voxel-wise within the single most prominent edematous bone marrow lesion per patient and examined for differences between MT1 degeneration and infectious spondylitis. Mean PDFF and PDFFratio of infectious spondylitis were significantly lower compared to MT1 degenerative changes (mean PDFF, 4.28 ± 3.12% vs. 35.29 ± 17.15% [p < 0.001]; PDFFratio, 0.09 ± 0.06 vs. 0.67 ± 0.37 [p < 0.001]). The areas under the curve (AUC) and diagnostic accuracies were 0.977 (p < 0.001) and 98.1% (cut-off at 12.9%) for PDFF and 0.971 (p < 0.001) and 98.1% (cut-off at 0.27) for PDFFratio. Our data suggest that quantitative evaluation of vertebral PDFF can provide a high diagnostic accuracy for differentiating erosive MT1 endplate changes from infectious spondylitis.

Q-Dixon and GRAPPATINI T2 Mapping Parameters: A Whole Spinal Assessment of the Relationship Between Osteoporosis and Intervertebral Disc Degeneration

BACKGROUND

The relationship between osteoporosis and intervertebral disc (IVD) degeneration remains controversial. Novel quantitative Dixon (Q-Dixon) and GRAPPATINI T2 mapping techniques have shown potential for evaluating the biochemical components of the spine.

PURPOSE

To investigate the correlation of osteoporosis with IVD degeneration in postmenopausal women.

STUDY TYPE

Prospective.

SUBJECTS

A total of 105 postmenopausal females (mean age, 65 years; mean body mass index, 26 kg/m² ).

FIELD STRENGTH/SEQUENCE

3 T; sagittal; 6-echo Q-Dixon, multiecho spin-echo GRAPPATINI T2 mapping, turbo spin echo (TSE) T1-weighted and TSE T2-weighted sequences.

ASSESSMENT

The subjects were divided into normal (N = 47), osteopenia (N = 28), and osteoporosis (N = 30) groups according to quantitative computed tomography examination. The Pfirrmann grade of each IVD was obtained. Region of interest analysis was performed separately by two radiologists (X.L., with 10 years of experience, and S.C., with 20 years of experience) on a fat fraction map and T2 map to calculate the bone marrow fat fraction (BMFF) from the L1 to L5 vertebrae and the T2 values of each adjacent IVD separately.

STATISTICAL TESTS

One-way analysis of variance, post-hoc comparisons, and Kruskal-Wallis H tests were performed to evaluate the differences in the magnetic resonance imaging parameters between the groups. The relationships between BMFF and the IVD features were analyzed using the Spearman correlation analysis and linear regression models.

RESULTS

There were significant differences in BMFF among the three groups. The osteoporosis group had higher BMFF values (64.5 ± 5.9%). No significant correlation was found between BMFF and Pfirrmann grade (r = 0.251, P = 0.06). BMFF was significantly negatively correlated with the T2 of the adjacent IVD from L1 to L3 (r = -0.731; r = -0.637; r = -0.547), while significant weak correlations were found at the L4 to L5 levels (r = -0.337; r = -0.278).

DATA CONCLUSION

This study demonstrated that osteoporosis is associated with IVD degeneration.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 4.

Differentiation of Diffuse Infiltration Pattern in Multiple Myeloma From Hyperplastic Hematopoietic Bone Marrow: Qualitative and Quantitative Analysis Using Whole-Body MRI

BACKGROUND

The visual assessment used for diffuse infiltration of multiple myeloma (MM) is inadequate. It can be difficult to differentiate MM from hyperplastic hematopoietic bone marrow (HHBM) because the MRI signal characteristics overlap.

PURPOSE

To analyze the bone marrow diffuse signal changes on whole-body MRI caused by MM and HHBM.

STUDY TYPE

Retrospective.

SUBJECTS

Thirty Four patients with MM (21 men and 13 women), 22 patients with HHBM (9 men and 13 women), and 15 healthy controls (9 men and 6 women).

FIELD STRENGTH/SEQUENCE

A 3.0 T MRI; diffusion-weighted whole-body imaging with background body signal suppression (DWIBS), modified Dixon T1 fast field echo, and T2 STIR.

ASSESSMENT

Three radiologists analyzed the whole-body MRI alone and in combination with apparent diffusion coefficient (ADC) and fat fraction (FF) with qualitative and quantitative analysis. Normalized T1 and T2 signal intensities (nT1 and nT2) and signal-to-noise ratio (SNR) were obtained.

STATISTICAL TESTS

Kruskal-Wallis and chi-square tests.

RESULTS

The MM group had significantly higher ADC and significantly lower FF than HHBM and control groups. There was no significant difference in nT1, nT2 or SNR between MM and HHBM (P = 0.932, P = 0.097, and P = 0.110, respectively). Receiver operating characteristic (ROC) analysis using ADC and FF cut-off values of 0.47 × 10^-3  mm² /sec and 20.63%, respectively. The AUC was 0.866 for ADC and 0.886 for FF. The quantitative analysis yielded better specificity (observer 1: 81.8% vs. 27.3%; observer 2: 68.2% vs. 22.7%; and observer 3: 72.7% vs. 18.2%) and a higher diagnostic accuracy (observer 1: 82.1% vs. 51.8%; observer 2: 80.4% vs. 50.0%; observer 3: 76.8% vs. 44.6%) than the qualitative analysis.

DATA CONCLUSION

Whole-body MRI combined with DWIBS and mDIXON could be used to differentiate between MM and HHBM. Combining the quantitative ADC and FF with the whole-body MRI improved the specificity and accuracy in differentiating these conditions.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.