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

Chemical shift-encoded MRI with compressed sensing combined with parallel imaging for proton density fat fraction measurement of the lumbar vertebral bone marrow

We aimed to investigate the accuracy of proton density fat fraction (PDFF) measurement of the lumbar vertebral bone marrow using chemical shift-encoded magnetic resonance imaging (CSE-MRI) with compressed sensing combined with parallel imaging (CSPI). This study recruited a commercially available phantom, and 43 patients. Fully sampled data without CSPI and under-sampled data with CSPI acceleration factors of 2.4, 3.6, and 4.8 were acquired using a 1.5T imaging system. The relationships between PDFF measurements obtained with the no-CSPI acquisition and those obtained with each CSPI acquisition were assessed using Pearson correlation coefficient (r), linear regression analyses, and Bland-Altman analysis. The intra- and inter-observer variabilities of the PDFF measurements were evaluated using the intraclass correlation coefficient. PDFF measurements obtained with all acquisitions showed a significant correlation and strong agreement with the reference PDFF measurement of the phantom. PDFF measurements obtained using CSE-MRI with and without CSPI were positively correlated (all acquisitions: r = 0.99; P < .001). The mean bias was -0.31% to -0.17% with 95% limits of agreement within ±2.02%. The intra- and inter-observer agreements were excellent (intraclass correlation coefficient: 0.988 and 0.981, respectively). A strong agreement and positive correlation were observed between the PDFF measurements obtained using CSE-MRI with and without CSPI. PDFF measurement of the lumbar vertebral bone marrow using CSE-MRI with CSPI can be acquired with a maximum reduction of approximately 75% in the acquisition time compared with a fully sampled acquisition.

Physiological gradient in lumbar spine fat fraction and R2* and its impact on osteoporosis diagnosis

BACKGROUND

Bone marrow adiposity and R2* have been explored as an imaging biomarker for osteoporosis. Chemical shift-encoded MRI (CSE-MRI) is a method that allows for relatively accurate measurement of adiposity and R2* in bone marrow in a simple manner. Additionally, there are reports of a physiological gradient of fat distribution in the lumbar spine. This physiological gradient of fat distribution can potentially impact the prediction of osteoporosis. Furthermore, the distribution of R2* is not well understood.

PURPOSE

This study examined how lumbar spine fat fraction (FF) and R2* change with different levels of the lumbar spine, how they influence osteoporosis prediction, and how they change according to measurement methods.

STUDY DESIGN/SETTING

Cross-sectional study using retrospectively collected data.

PATIENT SAMPLE

The study included patients who underwent dual-energy X-ray absorptiometry and lumbar spine CSE-MRI within one-month intervals between 2017 and 2022.

OUTCOME MEASURES

Reproducibility of FF and R2* based on measurement techniques, changes in FF and R2* according to vertebral level and osteoporosis status, and diagnostic power of osteoporosis based on vertebral level.

METHODS

Patients were categorized into the normal bone density, osteopenia, and osteoporosis groups based on bone mineral density. The relationship between groups and spine level before and after BMD adjustment was investigated using generalized estimating equations. Comparisons between the three groups and various measures of reliability were conducted using intraclass correlation coefficient. The diagnostic performance for predicting osteoporosis was evaluated with a receiver operating characteristic curve.

RESULTS

Comparing the three groups, FF increased with osteoporosis severity, while R2* decreased (p<.001). The intra/inter-rater agreement for FF and R2* was excellent. A physiological gradient within individuals was observed, where FF increased towards the lower lumbar spine (p=.002). R2* tended to decrease, but it was not statistically significant (p=.218). There was no statistically significant difference in the diagnosis of osteoporosis based on FF or R2* across different lumbar spine levels.

CONCLUSIONS

There was an increase in FF and a decrease in R2* from T12 to L5. However, the predictive power of osteoporosis did not significantly differ between each level.

CT and MR for bone mineral density and trabecular bone score assessment in osteoporosis evaluation

Dual energy X-ray absorptiometry (DXA) is widely used modality for measuring bone mineral density (BMD). DXA is used to measure the quantitative areal BMD of bone, but has the disadvantage of not reflecting the bone architecture. To compensate for this disadvantage, trabecular bone score (TBS), a qualitative parameter of trabecular microarchitecture, is used. Meanwhile, there have been recent attempts to diagnose osteoporosis using the Hounsfield unit (HU) from CT and MR-based proton density fat fraction (PDFF) measurements. In our study, we aimed to find out the correlation between HU/PDFF and BMD/TBS, and whether osteoporosis can be diagnosed through HU/PDFF. Our study revealed that the HU value showed a moderate to good positive correlation with BMD and TBS. PDFF showed a fair negative correlation with BMD and TBS. In diagnosing osteopenia and osteoporosis, the HU value showed good performance, whereas the PDFF showed fair performance. In conclusion, both HU values and PDFF can play a role in predicting BMD and TBS. Both HU values and PDFF can be used to predict osteoporosis; further, CT is expected to show better results.

Preliminary study for prediction of benign vertebral compression fracture age by quantitative water fraction using modified Dixon sequences: an imaging biomarker of fracture age

PURPOSE

This study aimed to evaluate whether quantitative water fraction parameters could predict fracture age in patients with benign vertebral compression fractures (VCFs).

METHODS

A total of 38 thoracolumbar VCFs in 27 patients imaged using modified Dixon sequences for water fraction quantification on 3-T MRI were retrospectively reviewed. To calculate quantitative parameters, a radiologist independently measured the regions of interest in the bone marrow edema (BME) of the fractures. Furthermore, five features (BME, trabecular fracture line, condensation band, cortical or end plate fracture line, and paravertebral soft-tissue change) were analyzed. The fracture age was evaluated based on clear-onset symptoms and previously available images. A correlation analysis between the fracture age and water fraction was evaluated using a linear regression model, and a multivariable analysis of the dichotomized fracture age model was performed.

RESULTS

The water fraction ratio was the only significant factor and was negatively correlated with the fracture age of VCFs in multiple linear regression (p = 0.047), whereas the water fraction was not significantly correlated (p = 0.052). Water fraction and water fraction ratio were significant factors in differentiating the fracture age of 1 year in multiple logistic regression (odds ratio 0.894, p = 0.003 and odds ratio 0.986, p = 0.019, respectively). Using a cutoff of 0.524 for the water fraction, the area under the curve, sensitivity, and specificity were 0.857, 85.7%, and 87.1%, respectively.

CONCLUSIONS

Water fraction is a good imaging biomarker for the fracture healing process. The water fraction ratio of the compression fractures can be used to predict the fracture age of benign VCFs.

How to distinguish thoracic and cervical lymph nodes during minimally invasive esophagectomy

Purpose

In this article, we aimed to reconstruct the cervical–thoracic junction plane (CTJP) using a three‐dimensional (3D) reconstruction system. Thus, the CTJP can be judged during surgery to better distinguish cervical–thoracic lymph nodes.

Methods

We included patients in Fujian Medical University Union Hospital from December 2019 to March 2020. All patients underwent a thin‐slice and enhanced computed tomography scan of the chest with 3D reconstruction using the IQQA system (EDDA technology) to reconstruct the CTJP, brachiocephalic trunk, right common carotid artery, and right subclavian artery. The distance from the intersection of the right subclavian artery and the CTJP to the origin of the right subclavian artery (ORSA) was measured, and the relationship between this distance and the patient's sex, BMI and height was analyzed.

Results

Seventy‐three patients were enrolled, of whom 12 had ORSA above the CTJP, while 61 had ORSA below the plane. There was a significant difference in age between the two groups (p = 0.04), compared with height, weight and BMI (p > 0.05). In 61 patients with the ORSA below the CTJP, the average distance was 24.7 ± 7.6 mm. The difference between the distance and BMI (p = 0.02) was statistically significant, and it was increased with increasing BMI.

Conclusions

The relationship between the ORSA and CTJP can be clarified through 3D reconstruction. The cervical‐thoracic recurrent laryngeal nerve lymph nodes can be distinguished clearly in minimally invasive esophagectomy, contributing to the accurate N staging of middle‐thoracic esophageal cancer.

Differentiation of bone metastases from benign red marrow depositions of the spine: the role of fat-suppressed T2-weighted imaging compared to fat fraction map

OBJECTIVE

To differentiate bone metastases (BMs) from benign red marrow depositions (BRMs) of the spine using quantitative parameters derived from fat-suppressed T2-weighted imaging (T2 FS) and fat fraction (FF) map METHODS: One hundred eleven lesions, divided into 62 BMs and 49 BRMs according to MR images and either bone scan or PET-CT, were assessed with T2 FS and FF map. Two radiologists independently measured quantitative parameters from the ROIs in the lesions, including fat-suppressed (FS) T2 ratio (ratio of lesion FS T2 signal intensity [SI] to normal marrow FS T2 SI), FF, and FF ratio (ratio of lesion FF to normal marrow FF). The mean values of these parameters were compared between the two groups. To evaluate the diagnostic utilities of individual (FS T2 ratio, FF, and FF ratio) and combined parameters, ROC curves were analyzed. For the ROC curves among the individual parameters and their combinations, AUCs were compared.

RESULTS

The FS T2 ratio of BMs was significantly higher than that of BRMs (2.638 vs. 1.155 [p < 0.001]). The FF and FF ratio of BMs were significantly lower than those of BRMs (FF, 3.554% vs. 20.038% [p < 0.001]; FF ratio, 0.072 vs. 0.364 [p < 0.001]). The ROC AUCs of individual and combined parameters ranged from 0.941 to 0.980. The AUCs of all individual parameters and their combinations did not demonstrate statistically significant differences.

CONCLUSION

The FS T2 ratio, FF, and FF ratio can be useful in differentiating BMs from BRMs with or without any combination of the parameters.

KEY POINTS

• Quantitative parameters derived from fat-suppressed T2-weighted imaging and fat fraction map could be used to differentiate bone metastases from benign red marrow depositions with or without any combination of the parameters. • Quantitative parameters of fat-suppressed T2-weighted imaging provide diagnostic performance similar to those of fat fraction map in differentiating bone metastases from benign red marrow depositions.

MRI-based vertebral bone quality score effectively reflects bone quality in patients with osteoporotic vertebral compressive fractures

OBJECTIVE

The present study is aimed to validate the ability of the vertebral bone quality (VBQ) score to evaluate bone quality in patients with osteoporotic vertebral compression fractures (OVCF) and to compare it with the ability of T-score by DXA. In addition, the sensitivity of VBQ score with cerebrospinal fluid (CSF) of L2 and L3 segments as baseline is evaluated.

METHODS

196 inpatients were collected and assigned into OVCF and Non-OVCF groups, respectively. For each patient, the VBQ score was calculated by the signal intensity of the L1-L4 vertebral bodies and CSF at L3 or L2 level from T1-weighted MRIs, while T-score from DXA was also obtained. The VBQ and T-score was compared between OVCF and non-OVCF groups, and among age groups. The OVCF ORs by VBQ score and T-score were calculated using logistic regression.

RESULTS

OVCF group was significantly different to the non-OVCF group in the T-score (- 2.9 vs. - 0.7) and VBQ score (4.0 vs. 3.5). VBQ score and T-score in patient aged 60-79 years old could indicate the bone quality, but only T-score in patients aged 50-59 years old. OVCF are associated with both higher VBQ score and lower T-score. The VBQ scores calculated by L2 CSF and L3 CSF were similar.

CONCLUSIONS

The VBQ score is an effective indicator of bone quality in OVCF patients and comparable to T-score, particularly in people over 60 years old. The VBQ score is not sensitive to CSF of different segments as a baseline.

Imaging of neuroendocrine tumors: A pictorial review of the clinical value of different imaging modalities

Neuroendocrine tumors (NETs) are multifaceted tumors occurring in a variety of organs and often present as metastatic at the time of diagnosis. Accurate staging is the most significant factor in therapy planning, but it remains a challenge. Imaging is established as the cornerstone for disease detection/diagnosis, staging, and follow up. To accurately assess and monitor tumor burden in patients with NETs, various imaging techniques have been developed and optimized. Current recommendations for the imaging of patients with NETs include a combination of both morphologic (or anatomic) and molecular imaging, but a final choice can be puzzling for clinicians. Recognizing that there is no uniform sequence consensus on the "best" imaging test, and the heterogeneity of technologic availability at different centers, we hope to provide a pictorial review of the different imaging techniques and their role and utility in management of patients with NETs, aimed to provide a practical guide for all clinicians.

Automatic detection of cervical lymph nodes in patients with oral squamous cell carcinoma using a deep learning technique: a preliminary study

OBJECTIVE

To apply a deep learning object detection technique to CT images for detecting cervical lymph nodes metastasis in patients with oral cancers, and to clarify the detection performance.

METHODS

One hundred and fifty-nine metastatic and 517 non-metastatic lymph nodes on 365 CT images in 56 patients with oral squamous cell carcinoma were examined. The images were arbitrarily assigned to training, validation, and testing datasets. Using the neural network, 'DetectNet' for object detection, the training procedure was conducted for 1000 epochs. Testing image datasets were applied to the learning model, and the detection performance was calculated.

RESULTS

The learning curve indicated that the recall (sensitivity) for detecting metastatic and non-metastatic lymph nodes reached 90% and 80%, respectively, while the model performance recall by applying the test dataset was 73.0% and 52.5%, respectively. The recall for detecting level IB and Level II metastatic lymph nodes was relatively high.

CONCLUSIONS

A system that has the potential to automatically detect cervical lymph nodes was constructed.