Corrigendum: Magnetization Transfer Ratio in Lower Limbs of Late Onset Pompe Patients Correlates With Intramuscular Fat Fraction and Muscle Function Tests

Objectives: Magnetization transfer (MT) imaging exploits the interaction between bulk water protons and protons contained in macromolecules to induce signal changes through a special radiofrequency pulse. MT detects muscle damage in patients with neuromuscular conditions, such as limb-girdle muscular dystrophies or Charcot-Marie-Tooth disease, which are characterized by progressive fiber loss and replacement by fatty tissue. In Pompe disease, in which there is, in addition, an accumulation of glycogen inside the muscle fibers, MT has not been tested yet. Our aim is to estimate MT ratio (MTR) in the skeletal muscle of these patients and correlate it with intramuscular fat fraction (FF) and results of muscle function tests.Methods: We obtained two-point axial Dixon and Dixon-MT sequences of the right thigh on a 1.5 Teslas MRI scanner in 60 individuals, including 29 late onset Pompe disease patients, 2 patients with McArdle disease, and 29 age and sex matched healthy controls. FF and MTR were estimated. Muscle function using several muscle function tests, including quantification of muscle strength, timed test quality of life scales, conventional spirometry obtaining forced vital capacity while sitting and in the supine position, were assessed in all patients.Results: MTR was significantly lower in Pompe patients compared with controls (45.5 ± 8.5 vs. 51.7 ± 2.3, Student T-test, p < 0.05). There was a negative correlation between the MTR and FF muscles studied (correlation coefficient: −0.65, Spearman test: p < 0.05). MTR correlated with most of the muscle function test results. We analyzed if there was any difference in MTR values between Pompe patients and healthy controls in those muscles that did not have an increase in fat, a measure that could be related to the presence of glycogen in skeletal muscles, but we did not identify significant differences except in the adductor magnus muscle (48.4 ± 3.6 in Pompe vs. 51 ± 1.3 in healthy controls, Student T-test = 0.023).Conclusions: MTR is a sensitive tool to identify muscle loss in patients with Pompe disease and shows a good correlation with muscle function tests. Therefore, the MT technique can be useful in monitoring muscle degeneration in Pompe disease in clinical trials or natural history studies.

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Correlation Between Respiratory Accessory Muscles and Diaphragm Pillars MRI and Pulmonary Function Test in Late-Onset Pompe Disease Patients

Frontiers in Neurology ◽

10.3389/fneur.2021.621257 ◽

2021 ◽

Vol 12 ◽

Author(s):

David Reyes-Leiva ◽

Jorge Alonso-Pérez ◽

Mercedes Mayos ◽

Claudia Nuñez-Peralta ◽

Jaume Llauger ◽

...

Keyword(s):

Pompe Disease ◽

Muscle Function ◽

Respiratory Muscle ◽

Late Onset ◽

Respiratory Support ◽

Fat Replacement ◽

Function Tests ◽

Fat Fraction ◽

Muscle Groups ◽

Over Time

Objectives: Pompe disease is a rare genetic disease produced by mutations in the GAA gene leading to progressive skeletal and respiratory muscle weakness. T1-weighted magnetic resonance imaging is useful to identify fatty replacement in skeletal muscles of late-onset Pompe disease (LOPD) patients. Previous studies have shown that replacement by fat correlates with worse results of muscle function tests. Our aim was to investigate if fat replacement of muscles involved in the ventilation process correlated with results of the spirometry and predicted respiratory muscle impairment in LOPD patients over time.Materials and Methods: We studied a cohort of 36 LOPD patients followed up annually in our center for a period of 4 years. We quantified muscle fat replacement using Mercuri score of the thoracic paraspinal and abdominal muscles and the pillars of the diaphragm. We correlated the combined Mercuri scores of these areas with spirometry results and the need of respiratory support.Results: We found a statistically significant correlation (Spearman test, p < 0.05; coefficient of correlation > 0.6) between forced vital capacity seated and lying and fat fraction score of all muscle groups studied. The group of patients who needed respiratory support had higher fat fraction scores than patients not requiring ventilatory support. Higher fat replacement in these areas correlated with worse progression in spirometry values over time.Conclusions: Fat replacement of paraspinal, abdominal, and trunk muscles correlates with results of spirometry and is able to predict worsening in respiratory muscle function tests that could lead to an emerging ventilatory dysfunction. Therefore, the identification of fat replacement in these muscle groups should lead to a closer monitorization of patients. Radiologic evaluation of diaphragm pillars in T1-weighted imaging axial sequences could also be helpful to predict respiratory insufficiency.

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A fast B1-mapping method for the correction and normalization of magnetization transfer ratio maps at 3 T

NeuroImage ◽

10.1016/j.neuroimage.2009.11.054 ◽

2010 ◽

Vol 49 (4) ◽

pp. 3015-3026 ◽

Cited By ~ 52

Author(s):

Steffen Volz ◽

Ulrike Nöth ◽

Anna Rotarska-Jagiela ◽

Ralf Deichmann

Keyword(s):

Magnetization Transfer ◽

Mapping Method ◽

Magnetization Transfer Ratio ◽

Transfer Ratio ◽

B1 Mapping

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Cervical cord magnetization transfer ratio and clinical changes over 18 months in patients with relapsing-remitting multiple sclerosis: a preliminary study

Multiple Sclerosis Journal ◽

10.1177/1352458506070714 ◽

2006 ◽

Vol 12 (5) ◽

pp. 662-665 ◽

Cited By ~ 18

Author(s):

A Charil ◽

D Caputo ◽

R Cavarretta ◽

M P Sormani ◽

P Ferrante ◽

...

Keyword(s):

Multiple Sclerosis ◽

Relapse Rate ◽

Magnetization Transfer ◽

Small Sample ◽

Cervical Cord ◽

Magnetization Transfer Ratio ◽

Short Term ◽

Disease Evolution ◽

Transfer Ratio ◽

Relapsing Remitting

Background Magnetization transfer ratio (MTR) permits the quantitative estimation of cervical cord tissue damage in patients with multiple sclerosis (MS). Objective To determine whether a single time-point MTR scan of the cervical cord is associated with short-term disease evolution in patients with relapsing-remitting (RR) MS. Methods Using a 1.5-T magnetic resonance imaging (MRI) system with a tailored cervical cord phased array coil, fast short-tau inversion recovery (fast-STIR) and MTR scans were obtained from 14 untreated patients with RRMS at baseline. Cervical cord MTR histograms were derived. Over the 18- month follow-up period, relapse rate was measured and disability assessed by the Expanded Disability Status Scale (EDSS) score. Results Average cervical cord MTR was correlated with relapse rate ( r= -0.56, P = 0.037). A moderate correlation ( r values ranging from -0.33 to -0.36) between baseline cervical cord MTR metrics and EDSS changes over 18 months was also noted, albeit statistical significance was not reached ( P = 0.26 and 0.21, respectively) perhaps because of the relatively small sample size. Conclusions This study suggests that a ‘snapshot’ MT MRI assessment of the cervical cord may detect cervical cord tissue changes associated with short-term disease evolution in RRMS.

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