Fast and accurate 3-D spine MRI segmentation using FastCleverSeg

Accurate and efficient segmenting of vertebral bodies, muscles, and discs is crucial for analyzing various spinal diseases. However, traditional methods are either laborious and time-consuming (manual segmentation) or require extensive training data (fully automatic segmentation). FastCleverSeg, our proposed semi-automatic segmentation approach, addresses those limitations by significantly reducing user interaction while maintaining high accuracy. First, we reduce user interaction by requiring the manual annotation of only two or three slices. Next, we automatically Estimate the Annotation on Intermediary Slices (EANIS) using traditional computer vision/graphics concepts. Finally, our proposed method leverages improved voxel weight balancing to achieve fast and precise volumetric segmentation in the segmentation process. Experimental evaluations on our assembled diverse MRI databases comprising 179 patients (60 male, 119 female), demonstrate a remarkable 25 ms (30 ms standard deviation) processing time and a significant reduction in user interaction compared to existing approaches. Importantly, FastCleverSeg maintains or surpasses the segmentation quality of competing methods, achieving a Dice score of 94%. This invaluable tool empowers physicians to efficiently generate reliable ground truths, expediting the segmentation process and paving the way for future integration with deep learning approaches. In turn, this opens exciting possibilities for future fully automated spine segmentation.

Transcranial ultrasonography as a reliable instrument for the measurement of the cerebral ventricles in rats with experimental hydrocephalus: a pilot study

PURPOSES

Demonstrate that transcranial ultrasonography (TUS) scanning is viable and useful as a diagnostic method in experimental hydrocephalus, as well as to compare measurements of cerebral and ventricular width obtained from TUS scans of hydrocephalic rats with post-mortem anatomical specimens, aiming for the development of accurate criteria to establish ventricular enlargement and progression of hydrocephalus subsequently.

METHODS

Thirty-five male Wistar rats were used. Following hydrocephalus induction, they underwent a transcranial ultrasound scan to measure cerebral and ventricular dimensions, in the fourth and 21 post-induction days. By the end of the experiments, measurements obtained from TUS scans were compared with actual values as seen in the post-mortem specimens of each animal.

RESULTS

Ventricular dilation could be clearly visualized in hydrocephalic animals. We performed intraclass correlation coefficient and linear regression analyses that have demonstrated a precise correlation between measurements of TUS scans and post-mortem specimens; we have found a similarity of 0,95 for the cerebral diameter and 0,97 for ventricular width.

CONCLUSIONS

Transcranial ultrasonography is a useful and reliable diagnostic tool for experimental hydrocephalus; also, it can be used to assess the progression of ventriculomegaly in animal models of hydrocephalus.

Association between spinal alignment and biochemical composition of lumbar intervertebral discs assessed by quantitative magnetic resonance imaging

Background

To evaluate potential associations between spinopelvic parameters and the biochemical composition of lumbar intervertebral discs using quantitative magnetic resonance imaging in asymptomatic young adults.

Methods

Our study group comprised 93 asymptomatic volunteers aged 20-40 years (49 women and 44 men). Lumbar spine T2-weighted images and T2 relaxometry were acquired on a 1.5T MRI scanner. Spinopelvic parameters including sacral slope, pelvic tilt, pelvic incidence, lumbar lordosis, thoracic kyphosis, thoracolumbar alignment, sagittal vertical axis, spinosacral angle, C2 pelvic angle, and T1S1 and L1S1 length were measured on panoramic spine radiographs.

Results

Lumbar lordosis decrease correlates with discrete dehydration of nucleus pulposus at all lumbar levels. Also low values of sacral slope, pelvic tilt, pelvic incidence, thoracic kyphosis and spinosacral angle were associated with decrease of T2 relaxation times on annulus fibrosus.

Conclusions

In conclusion, spinopelvic parameters presented a discrete association with lumbar disc composition and water content.

Spinopelvic sagittal balance: what does the radiologist need to know?

Sagittal balance describes the optimal alignment of the spine in the sagittal plane, resulting from the interaction between the spine and lower limbs, via the pelvis. Understanding sagittal balance has gained importance, especially in the last decade, because sagittal imbalance correlates directly with disability and pain. Diseases that alter that balance cause sagittal malalignment and may trigger compensatory mechanisms. Certain radiographic parameters have been shown to be clinically relevant and to correlate with clinical scores in the evaluation of spinopelvic alignment. This article aims to provide a comprehensive review of the literature on the spinopelvic parameters that are most relevant in clinical practice, as well as to describe compensatory mechanisms of the pelvis and lower limbs.

Concordance in prediction body fat percentage of Brazilian women in reproductive age between different methods of evaluation of skinfolds thickness

OBJECTIVE

To assess the utility of bioimpedance (BIA) and skinfolds thickness (SF) in body fat percentage measuring (%BF) compared to the reference method dual-energy x-ray absorptiometry (DXA) in Brazilian reproductive age women, as well as to estimate of inter- and intra-observer precision for SF.

SUBJECTS AND METHODS

170 women aged 18-37 years with BMI between 18 and 39.9 kg/m2 were selected for this cross-sectional study. Body density was evaluated through equations proposed by Jackson, Pollock and Ward (1980) (EqJPW) and Petroski (1995) (EqPET), and %BF was estimated by BIA, DXA and Siri's formula (1961). The SF were measured by two separate observers: A and B (to determine inter-observer variability), who measured the folds at three times with 10-minute interval between them (to determine intra-observer variability - we used only observer A).

RESULTS

The %BF by DXA was higher than those measured by SF and BIA (p<0.01, for all) of 90 volunteers. The Lin coefficient of agreement was considered satisfactory for %BF values obtained by EqJPW and BIA (0.55) and moderate (0.76) for sum of SF (ΣSF) values obtained by EqJPW and EqPET. No agreement was observed for the values obtained by SF (EqJPW and EqPET), BIA and DXA. Analysis of inter- and intra-observer of 59 volunteers showed that different measures of SF thickness met acceptability standards, as well as the % BF.

CONCLUSION

BIA and SF measurements may underestimate %BF compared with DXA. In addition, BIA and SF measurements are not interchangeable with DXA. However, our results suggest the equation proposed by Jackson, Pollock and Ward (three skinfolds) compared to BIA are interchangeable to quantify the %BF in Brazilian women in reproductive age. Furthermore, our results show acceptable accuracy for intra- and inter-observer skinfold measurements. Arch Endocrinol Metab. 2020;64(3):257-68.

Effective Parameters for Gait Analysis in Experimental Models for Evaluating Peripheral Nerve Injuries in Rats

Objective

Chronic constriction injury (CCI) of the sciatic nerve is a peripheral nerve injury widely used to induce mononeuropathy. This study used machine learning methods to identify the best gait analysis parameters for evaluating peripheral nerve injuries.

Methods

Twenty-eight male Wistar rats (weighing 270±10 g), were used in the present study and divided into the following 4 groups: CCI with 4 ligatures around the sciatic nerve (CCI-4L; n=7), a modified CCI model with 1 ligature (CCI-1L; n=7), a sham group (n=7), and a healthy control group (n=7). All rats underwent gait analysis 7 and 28 days postinjury. The data were evaluated using Kinovea and WeKa software (machine learning and neural networks).

Results

In the machine learning analysis of the experimental groups, the pre-swing (PS) angle showed the highest ranking in all 3 analyses (sensitivity, specificity, and area under the receiver operating characteristics curve using the Naive Bayes, k-nearest neighbors, radial basis function classifiers). Initial contact (IC), step length, and stride length also performed well. Between 7 and 28 days after injury, there was an increase in the total course time, step length, stride length, stride speed, and IC, and a reduction in PS and IC-PS. Statistically significant differences were found between the control group and experimental groups for all parameters except speed. Interactions between time after injury and nerve injury type were only observed for IC, PS, and IC-PS.

Conclusion

PS angle of the ankle was the best gait parameter for differentiating nonlesions from nerve injuries and different levels of injury.

Relationship of spinal alignment with muscular volume and fat infiltration of lumbar trunk muscles

Fat infiltration and atrophy of lumbar muscles are related to spinal degenerative conditions and may cause functional deficits. Spinal alignment exerts biomechanical influence on lumbar intervertebral discs and joints. Our objective was to evaluate if spinopelvic parameters correlate with the lumbar muscle volume and fat infiltration. This is an observational, prospective and cross-sectional study. Ninety-three asymptomatic adult aged 20–40 years were included. Lumbar lordosis (LL), thoracic kyphosis (TK), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), thoracolumbar alignment (TL), sagittal vertical axis (SVA), C2-pelvic angle (CPA), spinosacral angle (SSA), lack of lordosis (PI-LL), L1S1 and T1S1 length were measured on panoramic spine radiographs. Lumbar axial T1-weighted and In- and Out-Phase images were obtained on 1.5T MRI scanner and were used to extract the muscle volumes and fat fractions of multifidus, erector spinae, and psoas. All muscle volumes were higher in men than women (p<0.05). The fat fraction was higher in the multifidus and erector spinae in women (p<0.05). Multifidus volume was weakly correlated with PT (R = 0.22), PI (R = 0.22), LL (R = 0.34) and CPA (R = 0.29). Erectors spinae volume were correlated with CPA (R = 0.21). Psoas volume correlated with TK (R = 0.21), TL (R = 0.27) and SVA (R = -0.23). The lumbar muscle volumes showed a moderated correlation with T1S1 length (R = 0.55 to 0.62). Spinopelvic parameters showed correlation with lumbar muscle volumes but not with muscle fat infiltration on asymptomatic young adults.

Hyperbaric oxygen therapy reduces astrogliosis and helps to recovery brain damage in hydrocephalic young rats

PURPOSE

We investigated the possible beneficial effects that hyperbaric oxygen therapy could offer in different brain structures affected by ventriculomegaly in pup rats submitted to experimental hydrocephalus.

METHODS

Seven-day-old Wistar rats were submitted to hydrocephalus by intracisternal injection of 10% kaolin into the cisterna magna. The animals were divided into four groups: control (n = 5); control with HBOT (3ATA/2 h/day) (n = 5); untreated hydrocephalic (n = 10); hydrocephalic treated with HBOT (3ATA/2 h/day) (n = 10). The treatment with HBOT was performed daily for 14 days post-induction of hydrocephalus. To evaluate the response to treatment, behavioral tests (open field, Morris water maze, and activity monitor) were performed. After 14 days, the animals were euthanized, and the brain was removed for histological (hematoxylin-eosin and solochrome-cyanine) and immunohistochemical (GFAP and Ki-67) studies.

RESULTS

The hyperbaric treatment, although not causing changes in ventricular enlargement, resulted in a significant improvement in the behavioral performance (p = 0.0001), with greater agility and exploration of the environment, preservation of spatial memory, and greater learning capacity (p = 0.0001). Through the immunohistochemical study, the astrocytic activity (glial fibrillary acidic protein) in the corpus callosum (p = 0.0001) and in the germinative matrix (p = 0.0033) was significantly reduced as compared to that in the H group.

CONCLUSION

The results suggest that hyperbaric treatment bettered the behavioral performance and offered benefits to the structures affected by the ventricular increase helping to recover the brain damages. In this way, the HBOT it can be considered an adjuvant therapy for the treatment of hydrocephalus.

Association Between Lumbar Spine Sagittal Alignment and L4-L5 Disc Degeneration Among Asymptomatic Young Adults

STUDY DESIGN

Cross-sectional observational study on the relationship between the degrees of disc degeneration and sagittal alignment in asymptomatic healthy individuals.

OBJECTIVE

This study sought to determine whether the sagittal spine alignment subtype is related to the prevalence of lumbar disc degeneration.

SUMMARY AND BACKGROUND DATA

Sagittal balance and spinopelvic parameters might be risk factors for disc degeneration.

METHODS

A total of 70 asymptomatic participants (36 women and 34 men) without regular physical activity were categorized according to the four subtypes of sagittal alignment proposed by Roussouly. All participants underwent magnetic resonance imaging of the lumbar spine (1.5T) and panoramic radiography of the spine. The degree of disc degeneration was graded using T2-weighted images according to the Pfirrmann classification. Spinopelvic parameters and vertebral curvatures were measured on digital panoramic radiographs using Surgimap software. Interobserver analyses for the Pfirrmann classification and spinopelvic parameters were assessed using the weighted Kappa and intraclass correlation coefficient (ICC), respectively.

RESULTS

The Kappa associated with disc degeneration classification was 0.79 (95% confidence intervals 0.72-0.87). The ICCs were excellent, with small confidence intervals for all spinopelvic parameters. The type II group (flat lordosis) showed a higher frequency of degenerated discs at L4-L5 (P = 0.03) than the type IV group (long and curved lumbar spine). No significant differences in disc degeneration were observed among the four subtypes at the other disc levels. We found a negative, moderate correlation between the spinopelvic parameters and the occurrence of disc degeneration in the type II group.

CONCLUSION

The Roussouly subtype II sagittal alignment is significantly associated with disc degeneration at L4-L5 in asymptomatic young adults. Our results support the hypothesis that spinal sagittal alignment plays a role in early disc degeneration.

LEVEL OF EVIDENCE

3.

Lumbar intervertebral discs T2 relaxometry and T1ρ relaxometry correlation with age in asymptomatic young adults

BACKGROUND

To investigate the detection of intervertebral disc (IVD) composition aging-related changes using T2 and T1ρ relaxometry in vivo in asymptomatic young adults.

METHODS

We recruited ninety asymptomatic and young adults (42 men and 48 women) between 20 and 40 years old. T2 and T1ρ lumbar spine mappings were acquired using 1.5 T magnetic resonance imaging (MRI) scanner. Two independent observers manually segmented 450 lumbar discs in all slices. They also performed sub region segmentation of annulus fibrosus (AF) and nucleus pulposus (NP) at the central MRI sagittal slices.

RESULTS

There was no difference between men and women for T2 (P=0.37) or T1ρ relaxometry (P=0.97). There was a negative correlation between age (20-40 years) and IVD T2 relaxation time of the whole disc (r=-0.30, P<0.0001), NP (r=-0.20 to -0.51, P<0.05) and posterior AF (r=-0.21 to -0.31, P<0.05) at all lumbar disc levels. There was no statistical correlation between aging and IVD T1ρ relaxation both for NP and AF.

CONCLUSIONS

T2 relaxometry detected gradual IVD dehydration in the first two decades of adulthood. We observed no significant variation of T1ρ or volumetry with aging in our study group. Our results suggest that T2 mapping may be more appropriate to detect early IVD aging changes.

Classification of vertebral compression fractures in magnetic resonance images using spectral and fractal analysis

Fractures with partial collapse of vertebral bodies are generically referred to as "vertebral compression fractures" or VCFs. VCFs can have different etiologies comprising trauma, bone failure related to osteoporosis, or metastatic cancer affecting bone. VCFs related to osteoporosis (benign fractures) and to cancer (malignant fractures) are commonly found in the elderly population. In the clinical setting, the differentiation between benign and malignant fractures is complex and difficult. This paper presents a study aimed at developing a system for computer-aided diagnosis to help in the differentiation between malignant and benign VCFs in magnetic resonance imaging (MRI). We used T1-weighted MRI of the lumbar spine in the sagittal plane. Images from 47 consecutive patients (31 women, 16 men, mean age 63 years) were studied, including 19 malignant fractures and 54 benign fractures. Spectral and fractal features were extracted from manually segmented images of 73 vertebral bodies with VCFs. The classification of malignant vs. benign VCFs was performed using the k-nearest neighbor classifier with the Euclidean distance. Results obtained show that combinations of features derived from Fourier and wavelet transforms, together with the fractal dimension, were able to obtain correct classification rate up to 94.7% with area under the receiver operating characteristic curve up to 0.95.

T1ρ and T2 mapping of the intervertebral disk: comparison of different methods of segmentation

BACKGROUND AND PURPOSE

Intervertebral disk biochemical composition could be accessed in vivo by T1ρ and T2 relaxometry. We found no studies in the literature comparing different segmentation methods for data extraction using these techniques. Our aim was to compare different manual segmentation methods used to extract T1ρ and T2 relaxation times of intervertebral disks from MR imaging. Seven different methods of partial-disk segmentation techniques were compared with whole-disk segmentation as the reference standard.

MATERIALS AND METHODS

Sagittal T1ρ and T2 maps were generated by using a 1.5T MR imaging scanner in 57 asymptomatic volunteers 20-40 years of age. Two hundred eighty-five lumbar disks were separated into 2 groups: nondegenerated disk (Pfirrmann I and II) and degenerated disk (Pfirrmann III and IV). In whole-disk segmentation, the disk was segmented in its entirety on all sections. Partial-disk segmentation methods included segmentation of the disk into 6, 5, 4, 3, and 1 sagittal sections. Circular ROIs positioned in the nucleus pulposus and annulus fibrosus were also used to extract T1ρ and T2, and data were compared with whole-disk segmentation

RESULTS

In the nondegenerated group, segmentation of ≥5 sagittal sections showed no statistical difference with whole-disk segmentation. All the remaining partial-disk segmentation methods and circular ROIs showed different results from whole-disk segmentation (P < .001). In the degenerated disk group, all methods were statistically similar to whole-disk segmentation. All partial-segmentation methods, including circular ROIs, showed strong linear correlation with whole-disk segmentation in both the degenerated and nondegenerated disk groups.

CONCLUSIONS

Manual segmentation showed strong reproducibility for T1ρ and T2 and strong linear correlation between partial- and whole-disk segmentation. Absolute T1ρ and T2 values extracted from different segmentation techniques were statistically different in disks with Pfirrmann grades I and II.