Brain Alteration Patterns in Children with Duchenne Muscular Dystrophy: A Machine Learning Approach to Magnetic Resonance Imaging

Background

Duchenne Muscular Dystrophy (DMD) is a genetic disease in which lack of the dystrophin protein causes progressive muscular weakness, cardiomyopathy and respiratory insufficiency. DMD is often associated with other cognitive and behavioral impairments, however the correlation of abnormal dystrophin expression in the central nervous system with brain structure and functioning remains still unclear.

Objective

To investigate brain involvement in patients with DMD through a multimodal and multivariate approach accounting for potential comorbidities.

Methods

We acquired T1-weighted and Diffusion Tensor Imaging data from 18 patients with DMD and 18 age- and sex-matched controls with similar cognitive and behavioral profiles. Cortical thickness, structure volume, fractional anisotropy and mean diffusivity measures were used in a multivariate analysis performed using a Support Vector Machine classifier accounting for potential comorbidities in patients and controls.

Results

the classification experiment significantly discriminates between the two populations (97.2% accuracy) and the forward model weights showed that DMD mostly affects the microstructural integrity of long fiber bundles, in particular in the cerebellar peduncles (bilaterally), in the posterior thalamic radiation (bilaterally), in the fornix and in the medial lemniscus (bilaterally). We also reported a reduced cortical thickness, mainly in the motor cortex, cingulate cortex, hippocampal area and insula.

Conclusions

Our study identified a small pattern of alterations in the CNS likely associated with the DMD diagnosis.

Needle Depth and Angle for Lumbar Interlaminar Epidural Injection Using Magnetic Resonance Imaging and C-Arm Measurements

BACKGROUND

Interlaminar epidural injection (ILEI) is used to relieve low back pain, with or without radiating pain. The distance from the skin to the epidural space determines the needle depth and may be influenced by the patient's body measurements.

OBJECTIVES

The objective of this study was to investigate the correlation between needle depth for ILEI and patients' body profiles, including weight, height, and body mass index (BMI), using magnetic resonance imaging (MRI) and also to compare the needle depth and angle between MRI and C-arm fluoroscopic images of ILEI.

STUDY DESIGN

This was a retrospective study.

SETTING

This study was conducted at a single Department of Anesthesiology and Pain Medicine of Konkuk University Medical Center.

METHODS

This retrospective study reviewed patients who underwent MRI and ILEI. The needle depth and caudal angle were measured on the sagittal view of MRI and C-arm images for L3-L4, L4-L5, and L5-S1 ILEI.

RESULTS

Overall, 386 patients were reviewed. For MRI, the mean value of the needle angle given caudally was 14.70, 12.06, and 11.33 for L3-4, L4-5, and L5-S1 ILEIs, respectively. Mean values of needle depth were 52.17, 52.09, and 47.91 mm for L3-4, L4-5, and L5-S1 ESIs, respectively. Height combined with weight and BMI had a higher correlation with needle depth than weight and height. In the comparison between MRI and fluoroscopy, needle depth at L5-S1 and caudal angle at L3-4 and L4-5 were significantly correlated.

LIMITATIONS

This study was a retrospective study conducted at a single center.

CONCLUSION

Height combined with weight and BMI can help estimate the optimal needle depth from the skin to the epidural space. Needle depth in L5-S1 and caudal angle in L3-4 and L4-5 of MRI were correlated with those of fluoroscopy of ILEI.

Prospective, randomised comparison of two intravenous sedation methods for magnetic resonance imaging in children

BACKGROUND

Children usually need sedation or even anaesthesia for magnetic resonance imaging (MRI) studies. As there is no universally accepted method for this purpose we undertook a prospective, randomised comparison of propofol and dexmedetomidine in children aged 1 to 10 years.

METHODS

After Institutional Board approval and parents' informed consent 64 ASA status I or II children scheduled for MRI scan were enrolled. Patients were premedicated with intravenous (IV) midazolam (0.1 mg kg -1 ) and ketamine (1 mg kg -1 ) and randomised to propofol (P) or dexmedetomidine (D) group. A propofol bolus of 1 mg kg -1 followed by infusion of 4 mg kg -1 h -1 , or dexmedetomidine 1 µg kg -1 followed by 2 µg kg -1 h-1 infusion were used. Heart rate, SpO 2 and non-invasive blood pressure were monitored and recorded at 5 min intervals. Results were compared by means of standard statistical methods.

RESULTS

Both dexmedetomidine and propofol after premedication with ketamine and midazolam are suitable for MRI sedation, although propofol use results in shorter recovery time. Less interventions are needed when dexmedetomidine is used.

Biparametric MRI-based radiomics classifiers for the detection of prostate cancer in patients with PSA serum levels of 4∼10 ng/mL

Purpose

To investigate the predictive performance of the combined model by integrating clinical variables and radiomic features for the accurate detection of prostate cancer (PCa) in patients with prostate-specific antigen (PSA) serum levels of 4-10 ng/mL.

Methods

A retrospective study of 136 males (mean age, 67.3 ± 8.4 years) with Prostate Imaging-Reporting and Data System (PI-RADS) v2.1 category ≤3 lesions and PSA serum levels of 4-10 ng/mL were performed. All patients underwent multiparametric MRI at 3.0T and transrectal ultrasound-guided systematic prostate biopsy in their clinical workup. Radiomic features were extracted from axial T2-weighted images (T2WI) and apparent diffusion coefficient (ADC) maps of each patient using PyRadiomics. Pearson correlation coefficient (PCC) and recursive feature elimination (RFE) were implemented to identify the most significant radiomic features. Independent clinic-radiological factors were identified via univariate and multivariate regression analyses. Seven machine-learning algorithms were compared to construct a single-layered radiomic score (ie, radscore) and multivariate regression analysis was applied to construct the fusion radscore. Finally, the radiomic nomogram was further developed by integrating useful clinic-radiological factors and fusion radscore using multivariate regression analysis. The discriminative power of the nomogram was evaluated by area under the curve (AUC), DeLong test, calibration curve, decision curve analysis (DCA), and clinical impact curve (CIC).

Results

The transitional zone-specific antigen density was identified as the only independent clinic-radiological factor, which yielded an AUC of 0.592 (95% confidence interval [CI]: 0.527-0.657). The ADC radscore based on six features and Naive Bayes achieved an AUC of 0.779 (95%CI: 0.730-0.828); the T2WI radscore based on 13 features and Support Vector Machine yielded an AUC of 0.808 (95%CI: 0.761-0.855). The fusion radscore obtained an improved AUC of 0.844 (95%CI: 0.801-0.887), which was higher than the single-layered radscores (both P<0.05). The radiomic nomogram achieved the highest value among all models (all P<0.05), with an AUC of 0.872 (95%CI: 0.835-0.909). Calibration curve showed good agreement and DCA together with CIC confirmed the clinical benefits of the radiomic nomogram.

Conclusion

The radiomic nomogram holds the potential for accurate and noninvasive identification of PCa in patients with PI-RADS ≤3 lesions and PSA of 4-10 ng/mL, which could reduce unnecessary biopsy.

Prone Position MRI of the Lumbar Spine in Patients With Low Back Pain and/or Radiculopathy Refractory to Treatment

BACKGROUND

There are patients with limiting low back pain (LBP) with or without radicular pain in whom conventional supine magnetic resonance imaging (MRI) show no causative pathology. Despite the limitations of dynamic axially loaded MRI examinations, these imaging studies have shown a striking ability to diagnose pathology unrecognized by conventional MRI. The difference in findings between supine and prone MRI with patient symptom correlation has not been studied.

METHODS

Nineteen patients suffering from chronic moderate-to-severe LBP and/or radicular pain nonresponsive to conventional therapy or interventional treatment, were included in this study. Both supine and prone MRIs were performed and analyzed by a neuroradiologist. Specific supine and prone measurements were registered, including spinal canal area, lateral recess diameter, foraminal area, and ligamentum flavum thickness. Three-dimensional  MRI reconstructions of varying pathology patterns were created.

RESULTS

The mean patient age was 48.7 years (range [R]: 30-69), 63% of patients were women. The mean numeric pain score  was 6.5 (R: 4-8). In 52.6% of cases, disc pathology/increased disc pathology was seen only on prone imaging. We observed significant buckling and increased thickness of the ligamentum flavum in 52.6 % of cases in the prone position that was absent from the supine MRIs. We also documented varying grades of spondylolisthesis and facet joint subluxation resulting in significant foraminal stenosis in 26.3% of prone cases not seen from supine MRIs.

CONCLUSIONS

Four patterns of pathological findings have been identified by MRI performed in the prone position. These findings were not observed in the supine position. Prone MRI can be a significant and useful tool in the diagnosis and treatment of patients with back pain refractory to treatment whose conventional supine MRIs appeared unremarkable.

Anatomy of the Trigeminal Nerve and Its Clinical Significance Via Fusion of Computed Tomography and Magnetic Resonance Imagery

BACKGROUND

The Gasserian ganglion (GG) is the primary neuronal aggregation area of the trigeminal nervous system and the epidural structure outside the central nervous system, thus, it has become the most commonly used target for minimally invasive treatment of trigeminal neuralgia (TN). Whether it is the classic trigeminal radiofrequency treatment or GG balloon compression therapy, the intervention target is the GG. The anatomy and imaging anatomy of the GG of the trigeminal nerve is of great importance in the minimally invasive treatment of TN.

OBJECTIVE

To study the anatomy of the trigeminal nerve and multimodal image fusion, and to provide a basis for a clinical minimally invasive interventional treatment forTN.

STUDY DESIGN

Review, clinical research study.

SETTING

Department of Anesthesiology and Pain Medical Center, Jiaxing, China.

METHODS

Dissect the general structure of the trigeminal nerve and its positional relationship with adjacent structures, and use computed tomography (CT) and magnetic resonance imaging (MRI) to observe the trigeminal nerve, and then, perform a fusion of the CT/MR images.

RESULTS

The GG of the trigeminal nerve is located in Meckel's cave of the middle cranial fossa, and the 3 branches of the nerve fibers are intertwined. CT could only clearly show the bony structures adjacent to the GG, rather than the GG in the body, which was inconsistent with MR images. The bony structure was blurred, while the Meckel's cave and nerve roots, where the trigeminal nerve is located, could be clearly distinguished. Fusing the CT/MR images could provide 2 complementary advantages.

LIMITATIONS

It does not prove the the balloon position thought to be a "dumbbell" shape is adequate for the successful treatment.

CONCLUSION

Based on the anatomical structure and position of the trigeminal nerve, it is difficult to achieve highly selective branch treatment of TN with radiofrequency in the GG. For the treatment of TN with percutaneous microballoon compression on the GG, the balloon catheter should be placed in Meckel's cave. While it is not easy to insert into Meckel's cave, the depth of the balloon catheter should be that the distal end is flush with the top of the temporal bone petrous cone.

COMPARATIVE ANALYSIS OF FRACTAL DIMENSIONS OF HUMAN CEREBELLUM: IMPACT OF IMAGE PREPROCESSING AND FRACTAL ANALYSIS METHODS

OBJECTIVE

The aim: To compare the values of the fractal dimensions of human cerebellum obtained using different algorithms of image preprocessing and different methods of fractal analysis.

PATIENTS AND METHODS

Materials and methods: The study involved 120 people without structural changes in the brain (age 18-86 years, 55 men and 65 women). T1- and T2-weighted MR brain images were studied. Fractal analysis was performed using box counting and pixel dilatation methods. Fractal dimensions of cerebellar tissue as a whole, cerebellar cortex and its individual layers, cerebellar white matter were measured and compared to each other and to fractal dimension of cerebellar white matter determined in cadaveric cerebella.

RESULTS

Results: It was no significant difference between fractal dimension values of cerebellar tissue as a whole measured on T1 and T2 weighted magnetic resonance images of cerebellum, and fractal dimension values measured on the same images using different methods of fractal analysis - pixel dilatation and box counting. T2 weighted images are preferable for fractal analysis of different components of cerebellar tissue. Segmentation according to pixel luminance is the preferable image preprocessing method for fractal analysis of cerebellar cortex as a whole, individual cortical layers and cerebellar tissue as a whole; skeletonizing of cerebellar magnetic resonance images is the preferable method of the image preprocessing for fractal analysis of cerebellar white matter.

CONCLUSION

Conclusions: The algorithm of image preprocessing, magnetic resonance imaging sequence and method of fractal analysis should be chosen according to aim of quantitative study of cerebellar magnetic resonance images and features of the studied structure of cerebellum.

Vertebral Endplate Defect as Initiating Factor in Intervertebral Disc Degeneration: Strong Association Between Endplate Defect and Disc Degeneration in the General Population

STUDY DESIGN

Cross-sectional study of spine magnetic resonance in a population, predominantly female, sample.

OBJECTIVE

To determine the relationship between vertebral endplate defect and intervertebral disc degeneration (DD) in general population.

SUMMARY OF BACKGROUND DATA

Precise understanding of the mechanisms leading to DD development is lacking. In a degenerating disc, mechanical and structural changes lead to further worsening of disc integrity. Increasing attention has been paid to vertebral endplate defects as having a possible role in the etiopathogenesis of DD.

METHODS

The study population comprised 831 twin volunteers from TwinsUK (mean age 54 ± 8 yr, 95.8% female). Lumbar T2-weighted magnetic resonance images were coded for endplate defects from 8310 endplates into six grades. Total endplate score (TEP score) was achieved by summing both endplate defect grades from the same disc level. DD was evaluated using two different classifications; Pfirrmann grading, and a quantitative trait for DD based on a 4-point grading system. Multivariable regression analysis was used to determine relationships between the traits of interest and the known risk factors for DD, age, and body mass index (BMI). A receiver operator curve for TEP score predicting DD was generated, and survival analysis paired with Cox proportional hazards models analysis performed.

RESULTS

There was statistically significant association between DD and age and BMI. These associations lost significance when TEP score was included as predictor in multivariable model. TEP score was strongly and independently associated at every lumbar disc level with DD (Pfirmann P≤0.001; 4-point grading systems P < 1e-16). A cut-off point score of 5 for TEP score was found above which there was a higher DD prevalence. Across all age subgroups, probabilities of having DD were significantly increased in those considered TEP score positive (≥5).

CONCLUSION

Our large, population-based study has shown that endplate defect was strongly and independently associated with DD at every lumbar disc level. These results provide a mechanism by which increasing age and BMI predispose to DD.

LEVEL OF EVIDENCE

2.