Longitudinal Motor Functional Outcomes and Magnetic Resonance Imaging Patterns of Muscle Involvement in Upper Limbs in Duchenne Muscular Dystrophy

Neuromuscular imaging in clinical practice: an ESNR survey of 30 centers

PURPOSE

We assessed the current clinical imaging practice in the primary evaluation of neuromuscular disorders (NMD), with respect to standardized imaging, evaluation and reporting through a European and extra-European-wide survey.

METHODS

An online questionnaire was emailed to all European Society of Neuroradiology (ESNR) members (n = 1662) who had expressed their interest in NMD. The questionnaire featured 40 individual items. Information was gathered on the context of the practices, available and preferred imaging modalities, applied imaging protocols and standards for interpretation, reporting and communication.

RESULTS

A total of 30 unique entries from European and extra-European academic and non-academic institutions were received. Of these, 70% were neuroradiologists, 23% general radiologists and 7% musculoskeletal radiologists. Of the 30 responding institutes, 40% performed from 20 to 50 neuromuscular scans per year for suspected NMD. The principal modality used for a suspected myopathy was magnetic resonance imaging (MRI) (50%) or "mainly MRI" (47%). The primary imaging modality used for the evaluation of patients suspected of a neuropathy was MRI in 63% of all institutions and "mainly MRI" in 37%. For both muscle and nerve pathology, pelvic girdle and inferior limbs are the most scanned parts of the body (28%), followed by the thigh and leg (24%), whole body MR (24%), scapular girdle (16%), and the thigh in just 8% of institutions. Multiplanar acquisitions were performed in 50% of institutions. Convectional sequences used for muscle MRI included T2-STIR (88%), 2D T1weighted (w) (68%), T1 Dixon or equivalent (52%), T2 Dixon (40%), DWI (36%), 2D T2w (28%), T1 3D and T2 3D (20% respectively). For nerve MRI conventional sequences included T2-STIR (80%), DWI (56%), T2 3D (48%), 2D T2w (48%), T1 3D (44%), T1 Dixon or equivalent (44%), 2D T1 (36%), T2 Dixon (28%). Quantitative sequences were used regularly by 40% respondents. While only 28% of institutions utilized structured reports, a notable 88% of respondents expressed a desire for a standardized consensus structured report. Most of the respondents (93%) would be interested in a common MRI neuromuscular protocol and would like to be trained (87%) by the ESNR society with specific neuromuscular sessions in European annual meetings.

CONCLUSIONS

Based on the survey findings, we can conclude that the current approach to neuromuscular imaging varies considerably among European and extra-European countries, both in terms of image acquisition and post-processing. Some of the challenges identified include the translation of research achievements (related to advanced imaging) into practical applications in a clinical setting, implementation of quantitative imaging post-processing techniques, adoption of structured reporting methods, and communication with referring physicians.

Gain and loss of upper limb abilities in Duchenne muscular dystrophy patients: A 24-month study

Duchenne muscular dystrophy (DMD) is a neuromuscular condition characterized by muscle weakness. The Performance of upper limb (PUL) test is designed to evaluate upper limb function in DMD patients across three domains. The aim of this study is to identify frequently lost or gained PUL 2.0 abilities at distinct functional stages in DMD patients. This retrospective study analyzed prospectively collected data on 24-month PUL 2.0 changes related to ambulatory function. Ambulant patients were categorized based on initial 6MWT distance, non-ambulant patients by time since ambulation loss. Each PUL 2.0 item was classified as shift up, no change, or shift down. The study's cohort incuded 274 patients, with 626 paired evaluations at the 24-month mark. Among these, 55.1 % had activity loss, while 29.1 % had gains. Ambulant patients showed the lowest loss rates, mainly in the shoulder domain. The highest loss rate was in the shoulder domain in the transitioning subgroup and in elbow and distal domains in the non-ambulant patients. Younger ambulant patients demonstrated multiple gains, whereas in the other functional subgroups there were fewer gains, mostly tied to singular activities. Our findings highlight divergent upper limb domain progression, partly linked to functional status and baseline function.

Longitudinal Analysis of PUL 2.0 Domains in Ambulant and Non-Ambulant Duchenne Muscular Dystrophy Patients: How do they Change in Relation to Functional Ability?

BACKGROUND

The performance of upper limb 2.0 (PUL) is widely used to assess upper limb function in DMD patients. The aim of the study was to assess 24 month PUL changes in a large cohort of DMD patients and to establish whether domains changes occur more frequently in specific functional subgroups.

METHODS

The PUL was performed in 311 patients who had at least one pair of assessments at 24 months, for a total of 808 paired assessments. Ambulant patients were subdivided according to the ability to walk: >350, 250-350, ≤250 meters. Non ambulant patients were subdivided according to the time since they lost ambulation: <1, 1-2, 2-5 or >5 years.

RESULTS

At 12 months, the mean PUL 2.0 change on all the paired assessments was -1.30 (-1.51--1.05) for the total score, -0.5 (-0.66--0.39) for the shoulder domain, -0.6 (-0.74--0.5) for the elbow domain and -0.1 (-0.20--0.06) for the distal domain.At 24 months, the mean PUL 2.0 change on all the paired assessments was -2.9 (-3.29--2.60) for the total score, -1.30 (-1.47--1.09) for the shoulder domain, -1.30 (-1.45--1.11) for the elbow domain and -0.4 (-1.48--1.29) for the distal domain.Changes at 12 and 24 months were statistically significant between subgroups with different functional abilities for the total score and each domain (p <  0.001).

CONCLUSION

There were different patterns of changes among the functional subgroups in the individual domains. The time of transition, including the year before and after loss of ambulation, show the peak of negative changes in PUL total scores that reflect not only loss of shoulder but also of elbow activities. These results suggest that patterns of changes should be considered at the time of designing clinical trials.

Muscle-MRI and Functional Levels for the Evaluation of Upper Limbs in Duchenne Muscular Dystrophy: A Critical Review of the Literature

Many qualitative and quantitative Magnetic Resonance Imaging (MRI) techniques have been applied to evaluate muscle fat degeneration in Duchenne muscular dystrophy (DMD) subjects, but only few studies have focused on the upper limbs. We reviewed the literature in order to evaluate the association between muscle MRI findings and motor function levels in the upper limbs of DMD patients. Ten studies with upper limb muscle MRI data were available. Four explored all upper limb segments, while six explored only the forearm. Functional assessments were performed in nine of the ten studies. All of the studies showed a significant correlation between muscle MRI changes and motor function levels in both ambulant and non-ambulant DMD patients.