Keywords: Peripheral Nerves, Neurography

Motivation: Quantification of myelin in peripheral nerves remains challenging.

Goal(s): To evaluate new imaging techniques that quantify myelin in the peripheral nerve.

Approach:  Myelin-sensitive inversion recovery (MySIR) was compared with inhomogeneous magnetization transfer (ihMT) for its ability to reflect myelin value and spatial resolution in the peripheral nerve.

Results: Myelin values of MySIR and ihMT were strongly correlated. MySIR had a better ability to visualize nerve fascicles than ihMT.

Impact: MySIR could quantify myelin while maintaining high spacial resolution in peripheral nerves.

Keywords: Peripheral Nerves, Nerves, Median, Ulnar

Motivation: Improvements in the medical imaging of nerves have broad medical applications in the diagnosis, tracking, and management of peripheral nerve disease, injury, and treatment. 

Goal(s): We aim to demonstrate the feasibility of quantitative in vivo imaging of median and ulnar nerves using ultrashort echo time (UTE) MRI. 

Approach: UTE magnetization transfer (MT) prepared Cones (UTE MT-Cones), UTE MT Fat-Sat-Cones, and UTE Multi-echo-T₂-FS-Cones sequences were performed in nine healthy adults using a clinical 3T scanner. 

Results: Cross-sectional area (CSA), T₂*, MMF, and all MTR values were lower in the ulnar nerve, but the differences were significant only for CSA, non-fat-sat MTR 800-2k and 500-10k.

Impact: This demonstration of high-contrast, quantitative imaging of the wrist nerve has considerable potential in practical applications for managing and monitoring nerve disease, injury, and treatment.

Keywords: Peripheral Nerves, Nerves

Motivation: The median and ulnar nerves are fine anatomical structures, and these small nerves could not be adequately visualized on conventional MR neurography.

Goal(s): The purpose of this study is to realize high-resolution MR neurography for the diagnosis of peripheral neuropathy of the median and ulnar nerves.

Approach: We performed visualization of the detailed anatomy of the median and ulnar nerves by high-resolution diffusion sensitized-driven equilibrium (DSDE) with deep learning constrained Compressed SENSE (CS-AI) with deep learning constrained Compressed SENSE (CS-AI).

Results: MR neurography with DSDE with CS-AI could clearly visualize the median and ulnar nerves at high resolution within a feasible scan time.

Impact: High-resolution MR neurography with DSDE with CS-AI clearly visualizes the entire median and ulnar nerves, including the small common palmar digital nerves. This may be a useful technique in the diagnosis of peripheral neuropathy of the wrist.

Keywords: Peripheral Nerves, Nerves, denoising, DTI, FA

Motivation: DTI is effective in characterizing nerve pathology but requires a high-resolution scans, resulting in low SNR data.

Goal(s): To analyze the effectiveness of a self-supervised Patch2Self denoising technique on magnitude-averaged and complex-averaged DTI data of human median and ulnar nerve.

Approach: The magnitude-averaged and complex-averaged DTI data was denoised with the Patch2Self algorithm; and DTI fitting performed was performed to obtained estimates of FA, AD, and RD in nerves.

Results: Patch2Self denoising reduced the variability in the data by 20% at the cost of systematic bias, while complex averaging improved the contrast between muscle/nerve and suppressed fat.

Impact: FA estimates obtained from DTI helps monitor nerve regeneration following catastrophic nerve injuries. Improving the quality of the DTI data may improves the reliability of FA estimates so that more subtle treatment effects can be detected.

Keywords: Peripheral Nerves, Diabetes, DTI

Motivation: Electrophysiology is the gold-standard tool to diagnose diabetic peripheral neuropathy (DPN), but it is invasive. We try to find a convenient and reliable technique for diagnosing DPN.

Goal(s): The study aimed to reveal whether DTI of the lumbosacral nerve roots could be used to detect DPN.

Approach: Using a 3T MRI scanner to get the DTI parameters of lumbosacral nerve roots from 2 diabetic patients with and without DPN, respectively, and analyze data using statistical methods.

Results: DTI of lumbosacral nerve roots can detect whether peripheral nerve injury occurs in diabetic patients.

Impact: DTI of lumbosacral nerve roots can not only detect whether peripheral nerve injury occurs in diabetic patients but also quantitatively describe the degree of peripheral nerve injury and has the potential to evaluate the nerve changes after treatment in DPN patients.

Keywords: Head & Neck/ENT, Nerves, multi-shot, reduced-FOV, 3D isotropic DWI, optic nerves

Motivation: Conventional 2D DWI sequences suffer from several disadvantages, therefore hindering the clinical visual assessment of optic nerves. 

Goal(s): This study aims to enable a 3D reduced-FOV multi-shot isotropic DWI sequence for optic nerves DWI and verify its feasibility. 

Approach: The pulse sequence and corresponding reconstruction algorithm of 3D reduced-FOV 2-shot isotropic DWI was developed to achieve effective and accurate reconstruction of optic nerves.

Results: Preliminary results have shown the feasibility of our method in depicting the optic nerves with high resolution and high fidelity, therefore potentially benefiting the clinical applications of optic nerves DWI.

Impact: 3D reduced-FOV multi-shot isotropic optic nerves DWI shows superior advantages of high resolution and high fidelity compared with other conventional DWI sequences, which should be further investigated and applied for clinical applications of optic nerves.

Keywords: Peripheral Nerves, Nerves, Degenerative

Motivation: Multiple studies have shown volumetric changes in the dorsal root ganglia (DRG) in association with various neuropathies, but volumetric changes in patients with low back pain are not much known.

Goal(s): To check a semi-automatic region-growing technique can be used to segment DRG on 3D MR neurography images and to determine if DRG volumes differ in patients.

Approach: 3D MR neurography images were acquired from 10 patients and 4 control subjects at 3T. Segmentation algorithms were applied for DRG volume measurement, and measured volumes were compared between control and patient groups.

Results: Lower DRG volumes were measured with patients.

Impact: Through a semi-automatic 3D region growing technique, dorsal root ganglia volume can be efficiently measured with 3D MR neurography. Morphological assessment of dorsal root ganglia might help to understand overall lumbar spine pathology and low back pain.

Keywords: Peripheral Nerves, Nervous system, Radiomics, trigeminal neuralgia, nomogram, MRI

Motivation: Addressing the diagnostic challenges of Primary trigeminal neuralgia (PTN) and exploring the potential of radiomics combined with clinical features for better accuracy. 

Goal(s): To establish an auxiliary diagnostic model for PTN using radiomic and clinical features. 

Approach: Retrospectively analyzed 116 patients with trigeminal neuralgia, extracting 1316 radiomics features using 3D slicer and studying 13 clinical features. Lasso regression, ICC analysis, univariate and multivariate logistic regression were used for analysis. 

Results: Combining radiomic and clinical characteristics improved the model's AUC values to 0.85. Atrophy of the trigeminal roots might be significant in PTN diagnosis.

Impact: This study enhances PTN diagnosis, guiding clinicians with improved accuracy, potentially benefiting patients. It paves the way for further research on trigeminal root atrophy's role, optimizing treatment strategies and patient care.

Keywords: Structural Connectivity, Neurodegeneration

Motivation: Olfactory bulb and tract imaging with high resolution is required for patient evaluation

Goal(s): Optimized protocol along with super resolution deep learning to improve olfactory bulb and tract imaging 

Approach: Optimized T2 weighted and DTI imaging along with deep learning reconstruction was performed and results were evaluated

Results: Good agreement between existing and proposed methods were observed while the proposed methods improves resolution with better noise performance. 

Impact: This work will allow olfactory system high resolution imaging to serve as a diagnostic tool for patient evaluation.

Keywords: Peripheral Nerves, Diffusion Tensor Imaging, Magnetization Transfer

Motivation: Quantitative and semi-quantitative magnetic resonance imaging investigations of the peripheral nerves in vivo using 7 Tesla are currently limited.

Goal(s): To obtain standard diffusion tensor imaging (DTI) metrics and magnetization transfer ratio (MTR) in the healthy tibial nerve in vivo and to assess the reproducibility of these measures.

Approach: Reproducibility was assessed through repeated measurements (scan-rescan) and calculation of the coefficient of variation between measurements.

Results: The reproducibility assessment results are presented along with normative DTI and MTR measures in the tibial nerve, which can serve as reference in future studies of pathological conditions affecting the lower peripheral nerves.

Impact: This pilot study demonstrates the feasibility of using 7 Tesla magnetic resonance imaging to assess the healthy tibial nerve in vivo using diffusion-weighted and magnetization transfer imaging, opening up the possibilities to investigate lower peripheral neuropathies with higher spatial resolution.

Keywords: Peripheral Nerves, Neurography

Motivation: A more consistent visualization of the thoracic ganglia is needed to aid in identifying abnormal anatomical patterns and disease progression for the formulation of therapeutic strategies.

Goal(s): To prospectively evaluate the clinical feasibility of MR neurography in detecting thoracic dorsal root ganglia and related morphologic information for clinical decisions.

Approach: The T2_FFE, B_FFE, and SHINKEI sequences were applied to identify the best sequence that can precisely provide nerve root visualization and describe the morphological information of thoracic DRG.

Results: T2_FFE offers enhanced nerve visualization and improved image quality, and provides valuable morphological information, with shorter sequence acquisition time.

Impact: This method has a potential role in the diagnosis and treatment of diseases involving unilateral or even bilateral ganglia. By applying morphological MRN, the detailed nerve visualization may help surgeons develop effective DRG-targeted treatment and detect the therapeutic effect.

Keywords: Peripheral Nerves, Neurography, Nervous System, cadaveric MRI, vagus nerve

Motivation: Clinical visualization of the vagus nerve is challenging due to nerve diameter and tortuosity, as well as variation between subjects, making implementation of stimulation therapies difficult.  

Goal(s): Determine feasibility of bilateral vagus visualization in embalmed cadavers using high-resolution imaging.

Approach: Thirteen cadavers were imaged at 0.5-0.6 mm isotropic resolution using 3D constructive interference in steady state (CISS) and volumetric interpolated breath-hold sequence (VIBE). Scanning covered the extent of the vagus from the skull base to the abdomen and imaging was correlated to gross dissection.

Results: The vagus nerve was visualized bilaterally most clearly with CISS and 0.5mm uninterpolated spatial resolution.

Impact: MRI visualization of the vagus, cranial nerve X, could be used to direct future interventions including potential percutaneous MRI-guided procedures. Cadaveric imaging can help optimize acquisitions for future in vivo translation.

Keywords: Head & Neck/ENT, Head & Neck/ENT

Motivation: Identification of the spatial relationship between the parotid tumor and the extracranial segment of the facial nerve can facilitate preoperative planning.

Goal(s): We compared image quality and diagnostic efficacy between double-echo steady-state with water (DESS) and constructive interference in steady-state (CISS) sequences.

Approach: DESS and CISS sequences were used to determine the visibility of the extracranial segment of the facial nerve in healthy volunteers, then locate parotid tumors and facilitate patient diagnosis.

Results: Compared with DESS images, CISS images more reliably showed the location of the facial nerve relative to the lesion in patients with parotid tumors

Impact: CISS demonstrates good visualization of the parotid branches (temporofacial and cervicofacial trunks) compared with DESS. Moreover, CISS is a reliable and direct method for identifying the locations of parotid tumors.

Keywords: Peripheral Nerves, Treatment, trigeminal neuralgia; carbamazepine

Motivation: While MRI have proven valuable in predicting the surgical prognosis of trigeminal neuralgia (TN), studies on the prediction of medical therapy efficacy are still lacking.

Goal(s): Our goal was to identify MRI and clinical characteristics that can predict the efficacy of medical therapy for TN.

Approach: We conducted a blindly evaluation of MRI characteristics of TN. Clinical characteristics was obtained from the medical notes or phone follow-up. The correlation between MRI and clinical characteristics with medical therapy efficacy were subsequently analyzed.

Results: Vertebral artery being culprit vessel and involvement of trigeminal nerve ophthalmic division correlates with drug treatment efficacy.

Impact: The identified MRI and clinical characteristics in patients with TN, which are associated with the efficacy of medical therapy, can assist clinicians in offering informed guidance to patients when deciding between surgical and medical therapy.

Keywords: Head & Neck/ENT, Neurography, CRANI (CRanial Nerve Imaging), Parotid Mass

Motivation: Restricted visualization of the extra foraminal facial nerve inhibits pre-operative decision-making in parotid gland mass regarding nerve preservation.

Goal(s): Using 3D CRANI (CRanial Nerve Imaging) MR sequence, extra foraminal facial nerve was studied, focusing its anatomical relationship to parotid gland mass.

Approach: In 10 patients, post-contrast CRANI sequence was obtained in  3T scanner with 32-ch coil and Compressed SENSE imaging to study its extraforaminal course. Multi-planar and maximum-intensity projections was generated to enhance visibility.

Results: Extraforaminal segments of the facial nerve was well visualized up to its bifurcation. However, the visualization of branches distal to bifurcation in relation to the lesion was poor.

Impact: Extraforaminal facial nerve and its relationship to parotid mass allows surgeons to make better preoperative assessments. CRANI sequence effectively enables proximal nerve tracking while lacks in distal branch visualization in presence of mass; an avenue for future refinements. 

Keywords: Head & Neck/ENT, Brain Connectivity

Motivation: Trigeminal neurogenic tumors involving the peripheral branches are relatively rare, and valueable.Luckly,I collect many kind of neurogenic tumor including rare case.

Goal(s): CT and MR imaging can illustrate related anatomy
and pathway of three peripheral branches of the trigeminal neurogenic tumors.

Approach: We obtained MR and  CT images of all the adult Chinese patients during regular clinical trial with their informed consent. 

Results: Imaging features include irregular thickening and enhancement of the nerve, furthermore to clearly display supra-orbital, infra-orbital, and inferior alveolar nerves respectively.Surprisely,it  also widened the neural foramen those neurogenic nerves pass through. 

Impact: A thorough understanding of its anatomy and pathwayis very important, both in diagnosis and treatment of tumors.It really provided a important clinical guiding for proper practice.