54 research outputs found
The association between occupational loading and spine degeneration on imaging – a systematic review and meta-analysis
Vascularization of the human intervertebral disc: A scoping review
Intervertebral discs (IVDs) are often referred to as the largest avascular structures of the human body, yet a collective resource characterizing the vascularization of the IVD does not exist. To address this gap, the objective of this study was to conduct a comprehensive search of the literature to review and summarize current knowledge of the prevalence and localization of blood supply in human IVDs, with a scoping review. A comprehensive search of peer-reviewed publications on the topic of IVD vascularization in humans was conducted across six electronic databases: PubMed, EMBASE, MEDLINE, Scopus, Web of Science, and BIOSIS Previews. Studies of humans were included regardless of age, sex, ethnicity, and health status, with the exception of IVD herniation. Two independent reviewers screened titles and abstracts and full-texts according to eligibility criteria. The review was conducted and reported according to Preferred Reporting Items for Systematic Reviews Extension for Scoping Reviews guidelines. Our search yielded 3122 articles, with 22 articles meeting the inclusion criteria. The study samples ranged in age from fetal to \u3e90 years and included both sexes, various health statuses, and used different methodologies (eg, histology, medical imaging, and gross dissection) to assess vasculature. Overall, consistent observations were that (a) the nucleus pulposus of the IVD is avascular throughout life, (b) both the cartilage endplates and annulus fibrosus receive considerable blood supply early in life that diminishes over the lifespan, and (c) vascular ingrowth into the cartilage endplates and inner layers of the annulus fibrosus is commonly associated with damaged or disrupted tissue, irrespective of age. Histology and immunohistochemistry are often used to report vascularization of the IVD. The body of the current literature suggests that the IVD should not be generalized as an avascular tissue. Instead, vascularization of the IVD differs based on the constituent tissues, their age, and state of degeneration or damage
Bone-GAN: Generation of virtual bone microstructure of high resolution peripheral quantitative computed tomography
Background:Data-driven development of medical biomarkers of bone requires
a large amount of image data but physical measurements are generally too
restricted in size and quality to perform a robust training.
Purpose: This study aims to provide a reliable in silico method for the
generation of realistic bone microstructure with defined microarchitectural properties.
Synthetic bone samples may improve training of neural networks and
serve for the development of new diagnostic parameters of bone architecture
and mineralization.
Methods: One hundred-fifty cadaveric lumbar vertebrae from 48 different male
human spines were scanned with a high resolution peripheral quantitative CT.
After prepocessing the scans, we extracted 10,795 purely spongeous bone
patches, each with a side length of 32 voxels (5 mm) and isotropic voxel size
of 164 m. We trained a volumetric generative adversarial network (GAN) in
a progressive manner to create synthetic microstructural bone samples. We
then added a style transfer technique to allow the generation of synthetic samples
with defined microstructure and gestalt by simultaneously optimizing two
entangled loss functions. Reliability testing was performed by comparing real
and synthetic bone samples on 10 well-understood microstructural parameters.
Results: The method was able to create synthetic bone samples with visual
and quantitative properties that effectively matched with the real samples. The
GAN contained a well-formed latent space allowing to smoothly morph bone
samples by their microstructural parameters, visual appearance or both. Optimum
performance has been obtained for bone samples with voxel size 32 × 32
× 32, but also samples of size 64 × 64 × 64 could be synthesized.
Conclusions: Our two-step-approach combines a parameter-agnostic GAN
with a parameter-specific style transfer technique. It allows to generate an
unlimited anonymous database of microstructural bone samples with sufficient
realism to be used for the development of new data-driven methods of bonebiomarkers.
Particularly, the style transfer technique can generate datasets of
bone samples with specific conditions to simulate certain bone pathologies.Este artÃculo se encuentra publicado en Medical Physics, (Junio 2023
Measuring and reporting of vertebral endplate bone marrow lesions as seen on MRI (Modic changes): recommendations from the ISSLS Degenerative Spinal Phenotypes Group
How inter-rater variability relates to aleatoric and epistemic uncertainty: a case study with deep learning-based paraspinal muscle segmentation
Recent developments in deep learning (DL) techniques have led to great
performance improvement in medical image segmentation tasks, especially with
the latest Transformer model and its variants. While labels from fusing
multi-rater manual segmentations are often employed as ideal ground truths in
DL model training, inter-rater variability due to factors such as training
bias, image noise, and extreme anatomical variability can still affect the
performance and uncertainty of the resulting algorithms. Knowledge regarding
how inter-rater variability affects the reliability of the resulting DL
algorithms, a key element in clinical deployment, can help inform better
training data construction and DL models, but has not been explored
extensively. In this paper, we measure aleatoric and epistemic uncertainties
using test-time augmentation (TTA), test-time dropout (TTD), and deep ensemble
to explore their relationship with inter-rater variability. Furthermore, we
compare UNet and TransUNet to study the impacts of Transformers on model
uncertainty with two label fusion strategies. We conduct a case study using
multi-class paraspinal muscle segmentation from T2w MRIs. Our study reveals the
interplay between inter-rater variability and uncertainties, affected by
choices of label fusion strategies and DL models.Comment: Accepted in UNSURE MICCAI 202
MRI evaluation of the effects of extension exercises on the disc fluid content and location of the centroid of the fluid distribution
L’asymétrie significative au niveau des coupes sectionnelles des muscles paraspinaux chez des adultes en santé : une remise en question de ce marqueur dans la pathologie de la lombalgie
Study Design: A cross-sectional population-based study of paraspinal muscle asymmetry.
Objective: To examine level- and side-to-side differences in paraspinal muscle areas on magnetic resonance images in a population-based sample of middle aged men without low back pain (LBP).
Summary of Background Data: Level- and side-specific multifidus muscle atrophy and fat infiltration have been suggested as possible markers for localized spinal pathology and LBP, but prior studies have limited generalizability due to small sample sizes, young age of samples and measurement issues.
Methods: From a general population sample of 600 twin men, those reporting no LBP during the prior year, no previous spinal fractures, and no bed rest for at least 1 week in the last 12 months were included in the study. All subjects had T2-weighted axial images available for the three lowest lumbar levels. Both total and fat-free cross-sectional areas (CSAs) of the multifidus and erector spinae muscles at the mid-disc level were measured. Intrarater reliability ranged between 0.90 and 0.98 for area measurements and 0.86 and 0.92 for measurements of side-to-side differences. Data were analyzed using descriptive statistics and paired t tests.
Results: Subjects consisted of 126 men whose mean multifidus total CSA measurements varied between 7.3 and 11.1 cm2 and between 6.9 and 10.8 cm2 for right and left sides, respectively,
depending on the level. The corresponding mean areas for erector spinae were 9.4 to 19.6 cm2 for right side and 10.4 to 19.7 cm2 for left side. The multifidus was larger on the right side than on the left side in 65% to 68% of subjects, depending on spinal level (p<0.001). The mean symmetry at the three lowest lumbar levels was 10% to 13.2% and was smallest at L4-L5. Multifidus side-to-side asymmetry ranged from 0.1% to 44.3%. For erector spinae, the left-side measurements tended to be larger, reaching statistical significance (p<0.0001) for the two lowest levels. The mean side-to-side asymmetry increased caudally for erector spinae, from 8.2% to 18.8% and was significantly different between adjacent levels (p<0.01). The amount of intramuscular fat significantly increased caudally for both muscles.
Conclusion: Paraspinal muscle asymmetry greater than 10% was commonly found in men without a history of LBP. This suggests caution in using level- and side-specific paraspinal muscle
asymmetry to identify subjects with LBP and spinal pathology
Is the location of the signal intensity weighted centroid a reliable measurement of fluid displacement within the disc?
Abstract Degenerated discs have shorter T 2 -relaxation time and lower MR signal. The location of the signal-intensity-weighted-centroid reflects the water distribution within a region-of-interest (ROI). This study compared the reliability of the location of the signal-intensity-weighted-centroid to mean signal intensity and area measurements. L4-L5 and L5-S1 discs were measured on 43 mid-sagittal T 2 -weighted 3T MRI images in adults with back pain. One rater analysed images twice and another once, blinded to measurements. Discs were semi-automatically segmented into a whole disc, nucleus, anterior and posterior annulus. The coordinates of the signal-intensity-weighted-centroid for all regions demonstrated excellent intraclass-correlation-coefficients for intra- (0.99–1.00) and inter-rater reliability (0.97–1.00). The standard error of measurement for the Y-coordinates of the signal-intensity-weighted-centroid for all ROIs were 0 at both levels and 0 to 2.7 mm for X-coordinates. The mean signal intensity and area for the whole disc and nucleus presented excellent intra-rater reliability with intraclass-correlation-coefficients from 0.93 to 1.00, and 0.92 to 1.00 for inter-rater reliability. The mean signal intensity and area had lower reliability for annulus ROIs, with intra-rater intraclass-correlation-coefficient from 0.5 to 0.76 and inter-rater from 0.33 to 0.58. The location of the signal-intensity-weighted-centroid is a reliable biomarker for investigating the effects of disc interventions
A comparison of two methods to evaluate a narrow spinal canal: routine magnetic resonance imaging versus three-dimensional reconstruction
Reliability and validity of lumbar disc height quantification methods using magnetic resonance images
- …