MR Imaging of Brachial Plexus and Limb-Girdle Muscles in Patients with Amyotrophic Lateral Sclerosis.

PURPOSE: To assess brachial plexus magnetic resonance (MR) imaging features and limb-girdle muscle abnormalities as signs of muscle denervation in patients with amyotrophic lateral sclerosis (ALS). MATERIALS AND METHODS: This study was approved by the local ethical committees on human studies, and written informed consent was obtained from all subjects before enrollment. By using an optimized protocol of brachial plexus MR imaging, brachial plexus and limb-girdle muscle abnormalities were evaluated in 23 patients with ALS and clinical and neurophysiologically active involvement of the upper limbs and were compared with MR images in 12 age-matched healthy individuals. Nerve root and limb-girdle muscle abnormalities were visually evaluated by two experienced observers. A region of interest-based analysis was performed to measure nerve root volume and T2 signal intensity. Measures obtained at visual inspection were analyzed by using the Wald χ(2) test. Mean T2 signal intensity and volume values of the regions of interest were compared between groups by using a hierarchical linear model, accounting for the repeated measurement design. RESULTS: The level of interrater agreement was very strong (κ = 0.77-1). T2 hyperintensity and volume alterations of C5, C6, and C7 nerve roots were observed in patients with ALS (P < .001 to .03). Increased T2 signal intensity of nerve roots was associated with faster disease progression (upper-limb Medical Research Council scale progression rate, r = 0.40; 95% confidence interval: 0.001, 0.73). Limb-girdle muscle alterations (ie, T2 signal intensity alteration, edema, atrophy) and fat infiltration also were found, in particular, in the supraspinatus muscle, showing more frequent T2 signal intensity alterations and edema (P = .01) relative to the subscapularis and infraspinatus muscles. CONCLUSION: Increased T2 signal intensity and volume of brachial nerve roots do not exclude a diagnosis of ALS and suggest involvement of the peripheral nervous system in the ALS pathogenetic cascade. MR imaging of the peripheral nervous system and the limb-girdle muscle may be useful for monitoring the evolution of ALS and distinguishing patients with ALS from those with inflammatory neuropathy, respectively.

Muscle MRI findings in facioscapulohumeral muscular dystrophy.

OBJECTIVES: Facioscapulohumeral muscular dystrophy (FSHD) is characterized by extremely variable degrees of facial, scapular and lower limb muscle involvement. Clinical and genetic determination can be difficult, as molecular analysis is not always definitive, and other similar muscle disorders may have overlapping clinical manifestations. METHODS AND MATERIALS: Whole-body muscle MRI examination for fat infiltration, atrophy and oedema was performed to identify specific patterns of muscle involvement in FSHD patients (30 subjects), and compared to a group of control patients (23) affected by other myopathies (NFSHD). RESULTS: In FSHD patients, we detected a specific pattern of muscle fatty replacement and atrophy, particularly in upper girdle muscles. The most frequently affected muscles, including paucisymptomatic and severely affected FSHD patients, were trapezius, teres major and serratus anterior. Moreover, asymmetric muscle involvement was significantly higher in FSHD as compared to NFSHD patients. CONCLUSIONS: In conclusion, muscle MRI is very sensitive for identifying a specific pattern of involvement in FSHD patients and in detecting selective muscle involvement of non-clinically testable muscles. Muscle MRI constitutes a reliable tool for differentiating FSHD from other muscular dystrophies to direct diagnostic molecular analysis, as well as to investigate FSHD natural history and follow-up of the disease. KEY POINTS: Muscle MRI identifies a specific pattern of muscle involvement in FSHD patients. Muscle MRI may predict FSHD in asymptomatic and severely affected patients. Muscle MRI of upper girdle better predicts FSHD. Muscle MRI may differentiate FSHD from other forms of muscular dystrophy. Muscle MRI may show the involvement of non-clinical testable muscles.

Diffusion-weighted intensity magnetic resonance in the preoperative diagnosis of cholesteatoma.

We have analyzed the preoperative diagnosis of cholesteatoma through the use of diffusion-weighted intensity magnetic resonance (DWI-MR) in 16 consecutive patients suffering from chronic otitis media with clinical and radiological (by computed tomography) suspicion of cholesteatoma. In particular, we compared the radiological data with intraoperative ones, verifying the correspondence (in terms of sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy) between what is reported by DWI-MR and what is actually detectable at the time of surgery. Furthermore, we identified the most reliable DWI-MR sequence [single-shot (SSh) echo planar imaging (EPI) vs. multi-shot turbo spin-echo not-EPI] to detect cholesteatoma and reduce the time for examination. The obtained data on computed tomography scans revealed low diagnostic accuracy (56%); DWI-MR, instead, showed higher values, especially using not-EPI sequences (93.75 vs. 68.75% obtained by SSh-EPI sequences).