Keywords: Rare Disease, Cartilage

Motivation: To offer a quantitative imaging marker for monitoring of hemophilic joints.

Goal(s): To assess knee joint cartilage changes in children with hemophilic arthropathy(HA) using automated segmentation and explore their connection with Hemophilia Joint Health Scores(HJHS).

Approach: MRI were conducted on children with HA and healthy children using advanced techniques and automated cartilage segmentation to evaluate knee joint cartilage and their associations with HJHS.

Results: Significant differences in T1 and T2* values were found between HA and healthy controls, with positive correlations between T1 values in specific regions and HJHS, along with negative correlations between cartilage volume in specific regions and HJHS.

Impact: MRI techniques such as T1 mapping and T2* mapping hold promise for quantitatively assessing early-stage knee joint cartilage damage in HA, and show identifiable correlations with HJHS.

Keywords: MSK, Relaxometry, IVD, Spine, MSK, T2, NP, adolescence

Motivation: T₂ relaxation time is a promising biomarker for the hydration and maturation state of the IVD in children, however, very little is known about it.

Goal(s): The goal is to provide the baseline for T₂ relaxation times in thoracic IVDs in children.

Approach: T₂ relaxometry performed in thoracic IVDs of 10 children.

Results: In children: highest T₂ values are in the core of Nucleus Pulposus (200-270 ms), T₂ values in the Nucleus Pulposus - Annulus Fibrosus transition zone (110-130 ms) are more similar to those in adult NP tissue. This result is consistent with higher water content expected in pediatric vs. adult NP tissue.

Impact: T₂ values of healthy subjects can be used for the assessment of IVDs in children, opening new avenues to monitor developmental spine disease, research lower back pain as well as potential treatments.

Keywords: MSK, Adolescents, Pars Interarticularis, UTE, FE, Image Processing

Motivation: Fracture of pars interarticularis is a common injury in adolescent athletes, currently requiring CT scan for accurate diagnosis. 

Goal(s): Advance MR imaging to depict spinal bone with high fidelity.

Approach: Two techniques utilizing multiecho ultrashort echo time (UTE) and field echo (FE) with simple post-processing were developed to image lumbar spinal bone. SNR and CNR were determined, and clinical utility was assessed in patients.

Results: Improvements in visual quality and bone contrast were achieved using multiecho processing as opposed to a single echo inversion. Both UTE and FE techniques provided good bone contrast, although FE provide significantly better resolution and bone-muscle contrast.

Impact: This study advances MR imaging of the pars interarticularis for evaluation of spondylolysis. We demonstrated clinical feasibility in a patient with a pars defect, depicted with clarity with the techniques described here.

Keywords: MSK, MSK, oZTEo, DL

Motivation: Exploring oZTEo sequence with NEX=2 after AIR recon deep learning (DL) alternatives to 3D-ZTE for diagnosing bone diseases in children is clinically desirable. 

Goal(s): To compare the image quality among different kinds of oZTEo sequences. 

Approach:  A specimen and a child were subjected to different oZTEo MRI with and witout DL. The specimen was subjected to CT examination. The thicknesses of bone cortex and SNR of neighboring muscles were measured. 

Results: The image quality of oZTEo CT-like with NEX=2 after AIR recon DL was superior than that with NEX=6 before AIR recon DL.

Impact: The oZTEo technique with NEX=2 after AIR recon DL, with shorter scanning time and witout ionizing radiation, is a safer choice for diagnosing children bone diseases.

Keywords: Bone, Bone

Motivation: Femoral head necrosis can be clearly displayed by Black Bone MRI.

Goal(s): This study aimed to investigate the diagnostic performance of MR imaging with Black Bone sequence in the lateral pillar classification and femoral head extrusion index of Legg-Calvé-Perthes disease (LCPD) in children. 

Approach: The study included thirty-eight children with LCPD who underwent both X-ray and MR scans. The diagnostic performance of Black Bone MRI was assessed in comparison to X-ray. 

Results: The results showed that Black Bone had no significant difference in measuring the femoral head extrusion index compared to X-ray. For Herring classification, Black Bone MRI performed very well. 

Impact: Black Bone MRI can be used as a conventional sequence for the assessment of LCPD in children, allowing patients to avoid ionizing radiation.

Keywords: MSK, Bone

Motivation: Ionizing radiation risk from CT remains a concern for pediatric patients with craniofacial abnormalities.

Goal(s): Use high-resolution bone-selective MRI for cranial bone imaging and evaluate feasibility in pediatric patients.

Approach: We quantitatively assessed a new echo-subtraction UTE sequence against clinical CT and another well-known MRI technique to assess their strengths and limitations.

Results: The proposed UTE sequence had high agreement with CT among the 3D rendered bone segmentations in terms of Dice similarity coefficient and quantification of clinical craniometric measurements. Furthermore, the bone-selective MR images clearly depict thin bone structures with attenuation of both soft-tissues and air.

Impact: Craniofacial imaging with the proposed ultrashort echo time sequence has high agreement with CT in pediatric patients. MRI can be a reliable non-ionizing and radiation-free modality for pediatric patients who are at increased risk of radiation malignancy.

Keywords: Normal Development, Microstructure

Motivation: Early childhood bone development affects that of bone disease in adolescence and adulthood. Many diseases can affect the cancellous bone or bone marrow. Therefore, it is of great significance to quantify the bone development of healthy children.

Goal(s): To quantify the normal bone development and provide a basis for further studies focusing on diseases involving lumbar vertebrae.

Approach: This study was conducted to quantify the fat and cancellous bone content of lumbar vertebrae in healthy children based on IDEAL-IQ.

Results: As the age increased, the average PDFF and R2* both increased significantly. No association was found between the gender and PDFF, R2*.

Impact: As the age increased, the average PDFF and R2* of lumbar vertebrae both increased significantly in healthy children. These findings will probably improve our understanding of the bone development and enable differential diagnosis other diseases of children’s bone. 

Keywords: Muscle, Pediatric, neuromuscular disease

Motivation: A biomarker to assess the efficacy of Nusinersen is needed as it enhances motor function and prolongs survival in SMA patients.

Goal(s): We investigated whether qMRI could monitor the efficacy of Nusinersen in the treatment of SMA.

Approach: Patients underwent measurements of thigh qMRI (mDixon-Quant, T2 mapping and DTI) and Hammersmith Functional Motor Scale Expanded (HFMSE) before and after nusinersen treatment, X-ray exams to obtain Cobb angle were performed at baseline.

Results: After treatment, the mean thigh FF and FA decreased over time, and the HFMSE increased, while T2 values and ADC remain stable.

Impact: qMRI can evaluate the treatment outcomes of SMA patients. The younger patients with less scoliosis more likely to have minimumclinically significant difference at 6 months after treatment.   
 

Keywords: Muscle, Diffusion Tensor Imaging, cerebral palsy, passive torques

Motivation: Individuals with cerebral palsy (CP) often experience atypical biomechanical properties in the hand, yet little is known regarding the in vivo microstructural mechanisms in the muscle that underlie these impairments.

Goal(s): This study aimed to establish the relationship between diffusion MRI measures in forearm muscles and biomechanical features of the fingers.

Approach: Diffusion MR and torque measurements were acquired in five individuals with CP. Correlations between MR measures and the passive torque at the finger joints were investigated.

Results: Passive torque was significantly correlated with muscle volume (r=0.68,p=0.045) and FA (r=0.69,p=0.040), but FA and muscle volume were not significantly correlated with one another.

Impact: Diffusion MR-derived metrics such as FA and muscle volume have potential to be clinically translatable measures for identifying altered biomechanics in individuals with cerebral palsy and other populations with neuromuscular pathologies.