MR neurography of lumbosacral nerve roots: Diagnostic value in chronic inflammatory demyelinating polyradiculoneuropathy and correlation with electrophysiological parameters

Multifocal motor neuropathy in Japan: A nationwide survey on prevalence, clinical profiles, and treatment

INTRODUCTION/AIMS

Multifocal motor neuropathy (MMN) is a rare disease for which epidemiological and clinical data are limited. We conducted a nationwide survey to determine disease prevalence, incidence, clinical profile, and current treatment status in Japan.

METHODS

A nationwide survey was conducted in 2021 using an established epidemiological method. Questionnaires were sent to all neurology and pediatric neurology departments in Japan. An initial questionnaire was administered to determine the number of patients with and incidence of MMN. A second questionnaire was administered to collect detailed clinical information. The European Federation of Neurological Societies/Peripheral Nerve Society 2010 guidelines were used as diagnostic criteria.

RESULTS

The estimated number of patients with MMN was 507. The estimated prevalence was 0.40 per 100,000 individuals. Detailed clinical profiles were available for 120 patients. The male-to-female ratio was 2.3:1 and the median onset age was 42 years. The median disease duration at diagnosis was 25 months. Most patients presented with upper limb-dominant muscle weakness. Motor nerve conduction blocks were found in 62% of patients and positive anti-GM1 IgM antibody results in 54%. A total of 117 (98%) patients received immunoglobulin therapy, and 91% of them showed improvement. At the time of the last visit (median, 82 months from treatment initiation), 89 (74%) patients were receiving maintenance immunoglobulin therapy. A slight progression of neurological deficits was observed during follow-up.

DISCUSSION

Most patients with MMN in Japan received induction and maintenance immunoglobulin therapies, which appear to suppress long-term disease progression.

Quantitative magnetic resonance neurography in chronic inflammatory demyelinating polyradiculoneuropathy: A longitudinal study over 6 years

OBJECTIVE

To evaluate magnetic resonance neurography (MRN) for the longitudinal assessment of patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

METHODS

Prospective examination of twelve CIDP patients by neurological assessment, MRN, and nerve conduction studies in 2016 and 6 years later in 2022. Imaging parameters were compared with matched healthy controls and correlated with clinical and electrophysiological markers. The MRN protocol included T2-weighted imaging, diffusion tensor imaging (DTI), T2 relaxometry, and magnetization transfer imaging (MTI).

RESULTS

Nerve cross-sectional area (CSA) was increased in CIDP patients compared to controls (plexus: p = 0.003; sciatic nerve: p < 0.001). Over 6 years, nerve CSA decreased in CIDP patients, most pronounced at the lumbosacral plexus (p = 0.015). Longitudinally, changes in CSA correlated with changes in the inflammatory neuropathy cause and treatment validated overall disability sum score (INCAT/ODSS) (p = 0.006). High initial nerve CSA was inversely correlated with changes in the INCAT/ODSS over 6 years (p < 0.05). The DTI parameter fractional anisotropy (FA) showed robust correlations with electrodiagnostic testing both cross-sectionally and longitudinally (p < 0.05). MTI as a newly added imaging technique revealed a significantly reduced magnetization transfer ratio (MTR) in CIDP patients (p < 0.01), suggesting underlying changes in macromolecular tissue composition, and correlated significantly with electrophysiological parameters of demyelination (p < 0.05).

INTERPRETATION

This study provides evidence that changes in nerve CSA and FA reflect the clinical and electrophysiological course of CIDP patients. Initial nerve hypertrophy might predict a rather benign course or better therapy response.

The role of imaging in focal neuropathies

Electrodiagnostic testing (EDX) has been the diagnostic tool of choice in peripheral nerve disease for many years, but in recent years, peripheral nerve imaging has been used ever more frequently in daily clinical practice. Nerve ultrasound and magnetic resonance (MR) neurography are able to visualize nerve structures reliably. These techniques can aid in localizing nerve pathology and can reveal significant anatomical abnormalities underlying nerve pathology that may have been otherwise undetected by EDX. As such, nerve ultrasound and MR neurography can significantly improve diagnostic accuracy and can have a significant effect on treatment strategy. In this chapter, the basic principles and recent developments of these techniques will be discussed, as well as their potential application in several types of peripheral nerve disease, such as carpal tunnel syndrome (CTS), ulnar neuropathy at the elbow (UNE), radial neuropathy, brachial and lumbosacral plexopathy, neuralgic amyotrophy (NA), fibular, tibial, sciatic, femoral neuropathy, meralgia paresthetica, peripheral nerve trauma, tumors, and inflammatory neuropathies.

The diagnostic value of quantitative assessment of MR neurography in chronic inflammatory demyelinating polyradiculoneuropathy: a systematic review and meta-analysis

OBJECTIVES

The purpose of this study was to evaluate the diagnostic value of quantitative magnetic resonance neurography (MRN) in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We also compared various MRN parameters and determined the best performing one.

METHODS

Through literature searches in PubMed, Embase, Cochrane, Ovid MEDLINE and ClinicalTtrials.gov until March 1, 2023, we selected studies with the diagnostic performance of MRN in CIDP patients. The pooled estimated sensitivity and specificity of quantitative MRN parameters were determined by a bivariate random-effects model. Subgroup analysis was performed to evaluate the proper quantitative parameters and nerve sites.

RESULTS

A total of 14 quantitative MRN studies with 23 results gave a pooled sensitivity of 0.73 (95% CI 0.66-0.79) and a pooled specificity of 0.89 (95% CI 0.84-0.92). The area under the curve (AUC) was 0.89 (95%CI 0.86-0.92). Subgroup analysis of quantitative parameters showed the fractional anisotropy (FA) with the highest sensitivity of 0.85 (95% CI 0.77-0.90) and cross-sectional area (CSA) with the highest specificity of 0.95 (95% CI 0.85-0.99). The pooled correlation coefficient for interobserver agreements was 0.90 (95%CI 0.82-0.95).

CONCLUSION

Quantitative MRN has considerable diagnostic value in CIDP patients with accuracy and reliability. FA and CSA can be promising parameters in the future diagnosis of CIDP patients.

ADVANCES IN KNOWLEDGE

This is the first meta-analysis of quantitative MRN in the diagnosis of CIDP.We have selected reliable parameters with cut-off value and provided new insights for subsequent diagnosis of CIDP.

Multisequence magnetic resonance neurography of brachial and lumbosacral plexus in chronic inflammatory demyelinating polyneuropathy: correlations with electrophysiological parameters and clinical features

Background

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare and challenging demyelinating disorder. It is necessary to increase our understanding of potential connections between imaging, electromyography, and clinical characteristics.

Objective

The aim of this study was to evaluate the relationships between multisequence magnetic resonance neurography (MRN) findings, electrophysiological parameters, and clinical characteristics in CIDP patients.

Design

A cross-sectional study.

Methods

Overall, 51 CIDP patients underwent MRN of the brachial and lumbosacral plexus, and nerve conduction studies. The inflammatory Rasch-built overall disability scale (I-RODS) questionnaire, CIDP disease activity status (CADS) scale, and muscle strength scores were evaluated by two neurologists. Electrophysiological parameters, clinical information, and multiparameter-MRN were analyzed for correlations. Multiparameter-MRN includes diameter, nerve-to-muscle T2 signal intensity ratio (nT2), contrast-enhanced ratio (CR), fractional anisotropy (FA), and apparent diffusion coefficient (ADC) of bilateral plexus nerve roots.

Results

Electrophysiological parameters that were not elicited were significantly higher in the lower extremities than in the upper extremities, and those were higher in sensory nerve conduction than in motor. There were moderate correlations between motor nerve conduction velocity and distal motor latency in nerve diameter, nT2, FA, and ADC, respectively (|r|, 0.45-0.64, p < 0.05). The correlations between CR and sensory nerve conduction velocity and peak latency were moderate, and ADC had a positive correlation with compound motor action potential amplitude (|r|, 0.45-0.63). FA correlated negatively with the course (r = -0.62) and cerebrospinal fluid (CSF) protein (r = -0.41), whereas ADC had correlated positively with CSF protein (r = 0.34). Only CR had a moderately negative correlation with CADS (r's = -0.57). Muscle strength in all extremities was positively correlated with FA (r's range, 0.41-0.49). There was no significant correlation between I-RODS scores and multiparameter-MR.

Conclusion

MRN-derived multiparameter [nerve size, nT2, and diffusion tensor imaging (DTI) parameters] could serve as quantitative biomarkers of myelin sheath integrity in CIDP. DTI parameters and CR correlated with clinical characteristics better than morphological parameters-MR for CIDP patients.

Development of three-dimensional MR neurography using an optimized combination of compressed sensing and parallel imaging

PURPOSE

To assess the cervical magnetic resonance neurography (MRN) imaging quality obtained with compressed sensing and sensitivity-encoding (compressed SENSE; CS-SENSE) technique in comparison to that obtained with the conventional parallel imaging (i.e., SENSE) technique.

MATERIALS AND METHODS

Five healthy volunteers underwent a three-dimensional (3D) turbo spin-echo (TSE)-based cervical MRN examination using a 3.0 Tesla MR-unit. All MRN acquisitions were performed with CS-SENSE and conventional SENSE. We used four acceleration factors (4, 8, 16 and 32) in CS-SENSE. The image quality in MRN was evaluated by assessing the degree of cervical nerve depiction using the contrast ratio (CR) and contrast-noise ratio (CNR) between the cervical nerve and the background signal intensity and a visual scoring system (1: poor, 2: moderate, 3: good). In all of the CR, CNR and visual score, we calculated the ratio of the CS-SENSE-based MRN to that from SENSE-based MRN plus the 95% confidence intervals (CIs) of these ratios.

RESULTS

In the multiple comparison of MRN images with the control of conventional SENSE-based MRN, both the quantitative CR values and the visual score for the CS-SENSE factors of 16 and 32 were significantly lower, whereas the CS-SENSE factors of 4 and 8 showed a non-significant difference. In addition, the quantitative CNR values obtained with the CS-SENSE factors of 4 and 8 were significantly higher than that obtained with the conventional SENSE-based MRN while the CS-SENSE factor of 32 was significantly lower, in contrast, the CS-SENSE factors of 16 showed a non-significant difference. For CS-SENSE factors of 4 and 8, all ratios of the CS-SENSE-based MRN values for CR, CNR and visual scores to those from SENSE-based MRN were above 0.95.

CONCLUSION

CS-SENSE-based MRN can accomplish fast scanning with sufficient image quality when using a high acceleration factor.

Pathological Findings in Chronic Inflammatory Demyelinating Polyradiculoneuropathy: A Single-Center Experience

Objective: Segmental demyelination is the pathological hallmark of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), but other elementary lesions are frequently observed, configuring a series of different pathological pictures. In this article, we review the pathological findings of a large series of sural nerve biopsies from our cohort of CIDP patients. Patients and Methods: Patients with CIDP who underwent nerve biopsy were retrospectively selected from those referred to the Institute of Neurology of the “Università Cattolica del Sacro Cuore” in Rome, Italy, from 1982 to February 2020. Sural nerve biopsy was performed according to standard protocols. Results: Sural nerve biopsy was performed in 43/130 CIDP patients. Demyelinating abnormalities and axonal loss were found in 67.4% and 83.7% of biopsies, respectively. Conversely, onion bulbs and inflammatory infiltrates were rare (18.6% and 4.7%, respectively). In three cases, we observed normal pathological findings. Conclusions: A pathognomonic pathological finding of CIDP cannot be established, but we confirm the utility of nerve biopsy in this setting to confirm the diagnosis (also in atypical phenotypes) and to elucidate pathogenic mechanisms.