Pattern Of Fatty Infiltration Research Articles

Fatty infiltration of gastrocnemius-soleus muscle complex: Considerations for myosteatosis rehabilitation.

Although previous studies have reported fatty infiltration of the gastrocnemius-soleus complex, little is known about the volumetric distribution and patterns of fatty infiltration. The purpose of this anatomical study was to document and quantify the frequency, distribution, and pattern of fatty infiltration of the gastrocnemius-soleus complex. One hundred formalin-embalmed specimens (mean age 78.1 ± 12.3 years; 48F/52M) were serially dissected to document the frequency, distribution, and pattern of fatty infiltration in the medial and lateral heads of gastrocnemius and soleus muscles. Fatty infiltration was found in 23% of specimens, 13 unilaterally (8F/5M) and 10 (5M/5F) bilaterally. The fatty infiltration process was observed to begin medially from the medial aspect of the medial head of gastrocnemius and medial margin of soleus and then progressed laterally throughout the medial head of gastrocnemius and the marginal, anterior, and posterior soleus. The lateral head of gastrocnemius remained primarily muscular in all specimens. Microscopically, the pattern of infiltration was demonstrated as intramuscular with intact aponeuroses, and septa. The remaining endo-, peri-, and epimysium preserved the overall contour of the gastrocnemius-soleus complex, even in cases of significant fatty replacement. Since the external contour of the calf is preserved, the presence of fatty infiltration may be underdiagnosed in the clinic without imaging. Myosteatosis is associated with gait and balance challenges in the elderly, which can impact quality of life and result in increased risk of falling. The findings of the study have implications in the rehabilitation management of elderly patients with sarcopenia and myosteatosis.

MRI-based 3-dimensional volumetric assessment of fatty infiltration and muscle atrophy in rotator cuff tears.

The Goutallier and Warner Classification systems are useful in determining rotator cuff reparability. Data are limited on how accurately the scapular-Y view used in both systems reflects the 3-dimensional (3-D) changes in fatty infiltration (FI) and muscle atrophy (MA). Tendon retraction in the setting of a cuff tear may also influence the perception of these changes. This study's objectives were to (1) measure the 3-D volume of the supraspinatus muscle in intact rotator cuffs, and with varying magnitudes of retraction; (2) measure the 3-D volume of FI in the supraspinatus muscle in these conditions; and (3) determine the influence of tendon retraction on measured FI and MA using the Goutallier and Warner Classification Systems. Between August 2015 and February 2016, all shoulder magnetic resonance images (MRIs) at the Portland VA Medical Center were standardized to include the medial scapular border. MRIs and charts were reviewed for inclusion/exclusion criteria. Included MRIs were categorized into 4 groups based on rotator cuff retraction. Supraspinatus muscle and fossa were traced to create 3-D volumes. FI and MA were measured within the supraspinatus. The supraspinatus muscle was graded among 6 physicians using the Goutallier and Warner classification systems. These grades were compared to 3-D measured FI and MA. The influence of tendon retraction on the measured grades were also evaluated. One hundred nine patients met inclusion/exclusion criteria. Ten MRIs for each group (N=40) were included for image analysis. Supraspinatus volume tracings were highly reproducible and consistent between tracers. Supraspinatus muscle volumes decreased while global FI and MA increased with greater degrees of tendon retraction. In muscles with less than 10% global fat, fat concentrated in the lateral third of the muscle. In muscle with more than 10% global fat content, it distributed more diffusely throughout the muscle from medial to lateral. In comparing the scapular-Y to a medial cut, there was no consistent trend in FI whereas MA was more accurate at the medial cut. Parasagittal imaging location did not significantly influence the Goutallier score; however, assessment of MA using the Warner score leads readers to perceive less MA medially regardless of the magnitude of tendon retraction. The pattern of FI within the supraspinatus muscle changes from a laterally based location around the muscle-tendon junction to a more diffuse, global infiltration pattern when the whole muscle fat content exceeds 10%.

Muscle magnetic resonance imaging in patients with LAMA2-related muscular dystrophy

LAMA2-related muscular dystrophy (LAMA2-MD) is classified into congenital muscular dystrophy type 1A (MDC1A) and autosomal recessive limb-girdle muscular dystrophy-23 (LGMDR23). The purpose of this study was to identify the involvement pattern of thigh muscles of LAMA2-MD patients on magnetic resonance imaging. Fourteen MDC1A and 3 LGMDR23 patients were included, with 21 known and 8 novel LAMA2 disease-causing variants. In LAMA2-MD, the gluteus maximus, anterior (quadriceps femoris) and posterior (adductor magnus and biceps femoris) thigh muscles were extensively and severely affected with fatty infiltration, with relatively sparing of the adductor longus. The pattern of muscle involvement was similar between MDC1A and LGMDR23, but more severe in MDC1A, as well as in LAMA2-MD patients without ambulation. The rather peculiar pattern of the adductor magnus and long head of the biceps femoris first and severely affected in the mid-thigh level was found in LGMDR23. Strong correlation between fatty infiltration and age as well as disease duration was observed for the adductor longus in MDC1A. Edema and atrophy selectively involved in some muscles. The pattern of fatty infiltration on thigh muscle MRI of LAMA2-MD could provide important information for the diagnosis, differential diagnosis and assessment of clinical severity.

Radiographic analysis of fatty infiltration of the extraocular muscles in thyroid eye disease

ABSTRACT Purpose Fatty infiltration of the extraocular muscles has been described radiographically in patients with thyroid eye disease (TED), yet it has not been studied on a large scale nor quantified. Our purpose was to define and characterize this entity in patients with TED. Methods An IRB-approved cross-sectional retrospective review of medical records identified patients with a clinical diagnosis of TED and at least one CT of the orbits. A 2:1 age and sex-matched control population consisted of patients without a history nor radiographic evidence of orbital disease or systemic thyroid abnormality. The presence of fatty infiltration in each extraocular rectus muscle was defined using Hounsfield units (HU). Laterality, muscles involved, and pattern of fatty infiltration were also evaluated. Student’s t-tests, Chi-square, and Fisher’s exact tests were used to compare TED and control groups. Results The study population consisted of 252 patients with TED and 504 age and sex-matched controls. Fatty infiltration was significantly more prevalent in TED patients (36/252, 14.3%) compared to controls (11/504, 2.2%) (p < .001). The mean density of fat infiltration was significantly lower in TED patients (−40.4 HU) than controls (−34.8 HU) (p = .048). In TED patients, the frequency of muscle involvement was inferior rectus (61.8%), lateral rectus (19.7%), superior rectus (11.8%) and medial rectus (6.6%), which was not significantly different than controls (p > .05). Most muscles (88.2%) in the TED group exhibited a heterogeneous pattern of infiltration, which did not differ from controls (p = .34). Conclusions This study characterizes fatty infiltration of the extraocular muscles in patients with TED.

Value of muscle magnetic resonance imaging in the differential diagnosis of muscular dystrophies related to the dystrophin-glycoprotein complex

BackgroundDystrophin-glycoprotein complex (DGC)-related muscular dystrophies may present similar clinical and pathological features as well as undetectable mutations thus being sometimes difficult to distinguish. We investigated the value of muscle magnetic resonance imaging (MRI) in the differential diagnosis of DGC-related muscular dystrophies and reported the largest series of Chinese patients with sarcoglycanopathies studied by muscle MRI.ResultsFifty-five patients with DGC-related muscular dystrophies, including 22 with confirmed sarcoglycanopathies, 11 with limb-girdle muscular dystrophy 2I (LGMD2I, FKRP-associated dystroglycanopathy), and 22 with dystrophinopathies underwent extensive clinical evaluation, muscle biopsies, genetic analysis, and muscle MRI examinations. Hierarchical clustering of patients according to the clinical characteristics showed that patients did not cluster according to the genotypes. No statistically significant differences were observed between sarcoglycanopathies and LGMD2I in terms of thigh muscle involvement. The concentric fatty infiltration pattern was observed not only in different sarcoglycanopathies (14/22) but also in LGMD2I (9/11). The trefoil with single fruit sign was observed in most patients with dystrophinopathies (21/22), and a few patients with sarcoglycanopathies (4/22) or LGMD2I (2/11). Hierarchical clustering showed that most patients with sarcoglycanopathies or LGMD2I can be distinguished from dystrophinopathies based on the concentric fatty infiltration pattern and trefoil with single fruit sign at the thigh level on muscle MRI.ConclusionsMuscle MRI at the thigh level potentially allows distinction of sarcoglycanopathies or FKRP-associated dystroglycanopathy from dystrophinopathies.

Heterogeneous characteristics of MRI changes of thigh muscles in patients with dysferlinopathy.

The aim of this study was to evaluate the pattern of thigh muscle MRI changes in a large cohort of patients with dysferlinopathy. MRI of the thigh was performed in 60 patients. We correlated the scale of muscle involvement on MRI with the modified Gardner-Medwin and Walton (GM-W) scale and disease duration. We also analyzed the relationship between muscle changes and genetic mutations. Fatty infiltration and edema were observed in 95.50% and 86.67% of patients, respectively. The hamstring muscles had the highest frequency and mean score of fatty infiltration, although a posterior-dominant pattern was found in only 56%. Edema most commonly and severely affected the quadriceps and adductor magnus muscles. Fatty infiltration score correlated positively with disease duration and GM-W scale. The pattern of fatty infiltration was heterogeneous in dysferlinopathy patients. Muscle edema was common. Fatty infiltration can be used to assess disease progression. Muscle Nerve 54: 1072-1079, 2016.

Fibrofatty Changes: Incidence at Cardiac MR Imaging in Patients with Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy.

Purpose To determine the incidence of ventricular fatty replacement and late gadolinium enhancement (LGE) at cardiac magnetic resonance (MR) imaging in patients with arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C) and the relationship of these findings to disease severity. Materials and Methods This was a retrospective institutional review board-approved HIPAA-compliant study. All subjects provided written informed consent. Seventy-six patients with ARVD/C were enrolled from 2002 to 2012. Quantitative and qualitative cardiac MR imaging analyses of the RV and the left ventricle (LV) were performed to determine cardiac MR imaging-specific Task Force Criteria (TFC) and non-TFC features (ARVD/C-type pattern of fatty infiltration and/or nonischemic pattern LGE). Patients were separated into four groups on the basis of cardiac MR imaging TFC: (a) patients with major cardiac MR imaging criteria, (b) patients with minor criteria, (c) patients with partial criteria, and (d) patients with no criterion. Continuous variables were compared by using the independent Student t test and analysis of variance. Categoric variables were compared by using the Fisher exact test. Results Of 76 patients (mean age, 34.2 years ± 14 [standard deviation]; 51.3% men), 42 met major cardiac MR imaging criteria, seven met minor criteria, seven met partial criteria, and 20 met no criterion. Most probands (36 [80.0%] of 45) met major or minor cardiac MR imaging criteria. Only 13 (41.9%) of 31 family members met any cardiac MR imaging criterion. The most common non-TFC MR imaging features were RV fatty infiltration (28.9%) and LV LGE (35.5%). Non-TFC cardiac MR imaging features were seen in 88.1% of subjects with major criteria, in 28.6% of those with minor criteria, in 71.4% of those with partial criteria, and in 10.0% of those with no criteria. Conclusion In this large cohort of patients with ARVD/C, non-TFC findings of ventricular fatty infiltration and LGE were frequent and were most often found in those who met major cardiac MR imaging criteria and in probands. (©) RSNA, 2016 Online supplemental material is available for this article.

P.4.5 Muscle NMR imaging in the rare E650K mutation in the DNM2 gene in a centronuclear myopathy patient

Autosomal dominant centronuclear myopathy (CNM) is characterized by slowly progressive muscular weakness and wasting, and high frequency of centrally located nuclei in muscle fibers. The disorder involves mainly limb girdle, trunk and neck muscles but may also affect distal muscles. Ptosis and limitation of eye movements are frequent. Molecular analysis has identified recurrent mutations in exons 8 and 11 and rare heterozygous missense mutations in the dynamin-2 (DNM2) gene, which encodes a protein involved in endocytosis and membrane trafficking, actin assembly, and centrosome cohesion. We recently identified an isolated case of a 34 years old male patient, complaining of gait difficulties since the age of 14 years. Two years ago, the condition evolved to limb muscle weakness due to a predominantly distal severe lower limbs muscle atrophy associated to pes cavus. He also presented mild facial weakness with a discrete ptosis without ophtalmoparesis. By sequencing DNM2 exons, we found the rare heterozygous missense mutation c.1948G > A (p.E650K) in the DNM2 gene. This mutation was only described in one Chilean family. T1-weighted whole-body NMR imaging revealed fatty degenerative changes predominantly affecting the legs (score of 3 in a scale of 4), the face and the thighs. Thigh muscle displayed the particular reticular-punctuated pattern of fatty infiltration seen in CNM patients. The pattern of lesion distribution and the particular muscle texture observed in this patient are highly evocative of the disease. Therefore, NMR findings are showing comparable alterations in DNM2-related CNM patients, independently of the pathogenic mutation. FAPESP-CEPID, CNPQ-INCT, FINEP, CAPES-COFECUB.

A comparative analysis of fatty infiltration and muscle atrophy in patients with chronic rotator cuff tears and suprascapular neuropathy

Little is known of the mechanisms that lead to the muscle changes associated with rotator cuff disorders. We have observed that the magnetic resonance imaging (MRI) appearance of fatty infiltration (FI) and muscle atrophy (MA) differ between chronic cuff tears and suprascapular neuropathy, suggesting different pathophysiology. This study compares the different MRI changes that occur in chronic cuff tears and suprascapular neuropathy. Two groups were retrospectively identified: (1) RCT group (20 shoulders): patients with chronic tears of the supraspinatus and/or infraspinatus without electromyographic (EMG) evidence of suprascapular neuropathy; (2) neuro group (17 shoulders): patients with EMG documented suprascapular nerve dysfunction and absence of a rotator cuff tear. Magnetic resonance arthrograms were analyzed for the degree of FI and MA, and the morphology of the muscle was assessed, in particular the muscle border, pattern of FI, and extent of involvement. The muscle changes that occur following chronic cuff tears differ from that following denervation secondary to suprascapular neuropathy, especially with respect to the muscle border, degree of perineural fat, and overall distribution of FI. Highly specific and characteristic morphological patterns of FI exist for both chronic cuff tears and suprascapular neuropathy. Chronic rotator cuff tendon tears and suprascapular neuropathy are both associated with FIand MA of the rotator cuff muscles. The pattern of FI is markedly different in the 2 situations. These findings have diagnostic potential and may serve as a basis for further research concerning type, severity, and evolution of FI under different conditions and after treatment.