Magnetic resonance imaging analysis of the upper cervical spine extensor musculature in an asymptomatic cohort: an index of fat within muscle

Study on the consistency between CT hounsfield units and MRI evaluation of preoperative cervical paraspinal muscular fat infiltration in patients undergoing ACDF

OBJECTIVE

To explore the feasibility of applying CT Hounsfield Units (HUs) for the assessment of preoperative paraspinal muscle fat infiltration (FI) in different segments in patients who underwent anterior cervical discectomy and fusion (ACDF). To compare the consistency of preoperative paraspinal muscle FI evaluations using MRI and those via CT HUs in patients who underwent ACDF surgery.

METHODS

Ninety-five patients (45 males and 50 females, aged 37‒71 years) who received CT and MRI examinations and underwent ACDF surgery were retrospectively analyzed. In the axial T2-weighted MR images at the median level of the C3/4, C4/5, and C5/6 segments, regions of interests (ROIs) were delineated along the boundaries of the cervical multifidus (MF) and semispinalis cervicis (Scer) muscles. Using the threshold tool in ImageJ software, areas of fat tissue and intermuscular septa within the ROI were quantified. The effective cross-sectional area (ECSA) for each side was obtained by subtracting the areas of fat tissue and intermuscular septa from the total ROI area. The ratio of the fat tissue area to the CSA was then calculated to determine the initial FI value. The depth of subcutaneous fat from the midline spinous process to the epidermis at the median plane of the C4/5 intervertebral disc was measured. The initial FI values were then divided by the depth of fat to determine the post-correction FI value. Using the Picture Archiving and Communication System (PACS), at identical segments and planes, ROIs were delineated using the same method as in MRI under a standard soft tissue window (width of 500 HU, level of 60 HU). The CT HU values were measured within these defined areas. The CT HU values from both sides are summed to obtain the total HU value for the segment. According to whether the measurement results of two sets of data follow a normal distribution, Pearson's test or Sperman's test was used to analyze the correlation.

RESULTS

On MRI, a statistically significant difference was observed in the post-correction FI only at the C3/4 segment compared to the other two segments (P < 0.05). No significant difference in the post-correction FI between the C4/5 and C5/6 segments was noted (P > 0.05). The CT HU results showed a substantial discrepancy between C3/4 and C4/5 segments and between C3/4 and C5/6 segments (P < 0.05), whereas no statistically significant difference was found in the CT HU value between the C4/5 and C5/6 segments (P > 0.05). The consistency analysis revealed a relatively strong correlation between the post-correction FI and CT HU values of the C3/4 and C4/5 segments. Furthermore, a strong correlation was detected in the variations in the measurement outcomes at the C5/6 segment.

CONCLUSION

Patients requiring surgical treatment for the cervical spine exhibit varying degrees of FI in paraspinal muscles across different locations and segments. Evaluating the degree of FI in the paraspinal muscles of the cervical spine through CT HU values is feasible. There is considerable consistency between the post-correction FI assessed under MRI and the measurements of CT HU values in evaluating the FI of paraspinal muscles in the cervical spine.

Clinical and Radiological Outcomes in C2 Recapping Laminoplasty for the Pathologies in the Upper Cervical Spine

OBJECTIVE

To evaluate C2 muscle preservation effect and the radiological and clinical outcomes after C2 recapping laminoplasty.

METHODS

Fourteen consecutive patients who underwent C2 recapping laminoplasty around C1-2 level were enrolled. To evaluate muscle preservation effect, the authors conducted a morphological measurement of extensor muscles between the operated and nonoperated side. Two surgeons measured the cross-sectional area (CSA) of obliquus capitis inferior (OCI) and semispinalis cervicis (SSC) muscle before and after surgery to determine atrophy rates (ARs). Additionally, we examined range of motion (ROM), sagittal vertical axis (SVA), neck visual analogue scale (VAS), Neck Disability Index (NDI), and Japanese Orthopaedic Association (JOA) score to assess potential changes in alignment and consequent clinical outcomes following posterior cervical surgery.

RESULTS

We measured the CSA of OCI and SSC before surgery, and at 6 and 12 months postoperatively. Based on these measurements, the AR of the nonoperated SSC was 0.1% ± 8.5%, the AR of the operated OCI was 2.0% ± 7.2%, and the AR of the nonoperated OCI was -0.7% ± 5.1% at the 12 months after surgery. However, the AR of the operated side's SSC was 11.2% ± 12.5%, which is a relatively higher value than other measurements. Despite the atrophic change of SSC on the operated side, there were no prominent changes observed in SVA, C0-2 ROM, and C2-7 ROM between preoperative and 12 months postoperative measurements, which were 11.8 ± 10.9 mm, 16.3° ± 5.9°, and 48.7° ± 7.7° preoperatively, and 14.1 ± 11.6 mm, 16.1° ± 7.2°, and 44.0° ± 10.3° at 12 months postoperative, respectively. Improvement was also noted in VAS, NDI, and JOA scores after surgery with JOA recovery rate of 77.3% ± 29.6%.

CONCLUSION

C2 recapping laminoplasty could be a useful tool for addressing pathologies around the upper cervical spine, potentially mitigating muscle atrophy and reducing postoperative neck pain, while maintaining sagittal alignment and ROM.

Change in Lumbar Muscle Size and Composition on MRI with Long-Duration Spaceflight

Prolonged microgravity results in muscle atrophy, especially among the anti-gravity spinal muscles. How individual paravertebral muscle groups change in size and composition with spaceflight needs further exploration. This study investigates lumbar spine musculature changes among six crewmembers on long-duration space missions using non-invasive measurement of muscle changes with magnetic resonance imaging (MRI). Pre- and post-flight lumbar images were analyzed for changes in cross-sectional area, volume, and fat infiltration of the psoas (PS), quadratus lumborum (QL), and paraspinal [erector spinae and multifidus (ES + MF)] muscles using mixed models. Crewmembers used onboard exercise equipment, including a cycle ergometer (CEVIS), treadmill (T2/COLBERT), and the advanced resistive exercise device (ARED). Correlations were used to assess muscle changes related to exercise modality. There was substantial variability in muscle changes across crewmembers but collectively a significant decrease in paraspinal area (- 9.0 ± 4.8%, p = 0.04) and a significant increase in QL fat infiltration (7.3 ± 4.1%, p = 0.05). More CEVIS time may have protected against PS volume loss (p = 0.05) and PS fat infiltration (p < 0.01), and more ARED usage may have protected against ES + MF volume loss (p = 0.05). Crewmembers using modern onboard exercise equipment may be less susceptible to muscle changes. However, variability between crewmembers and muscle size and quality losses suggest additional research is needed to ensure in-flight countermeasures preserve muscle health.

Muscle fat infiltration but not muscle cross-sectional area is independently associated with bone mineral density at the lumbar spine

OBJECTIVE

Although sarcopenia and osteoporosis are inter-related conditions that are common with advancing age, few studies have explored relationships between muscle quality and bone mineral density (BMD). We investigated age- and sex-specific paraspinal muscle fat infiltration (MFI), muscle cross-sectional area (CSA), and spine volumetric BMD (vBMD) in healthy Chinese adults.

METHODS

605 healthy adults aged 20-59 years (340 women, mean age 39.2 years; 265 men, mean age 38.8 years) had axial T2WI MRI imaging of the lumbar spine and CSA (cm2) and MFI (%) were measured in the psoas and multifidus and erector spinae (MF-ES) muscles (L3-L4). MFI measurements were calibrated against a region of interest in an adjacent area of subcutaneous pure fat. L2-L4 vBMD was measured by quantitative CT. Age- and sex-specific subgroups were compared using the Mann-Whitney test. Multiple regression was used to test independent associations of MFI and CSA with vBMD.

RESULTS

Females had lower CSA and higher MFI than males in both the psoas and MF-ES muscles (p < 0.001). In females and males, MF-ES MFI increased with age (p < 0.001) and in females age-related increases were observed for the psoas muscles (p < 0.05). Greater fat infiltration of the MS-ES muscle unit was associated with lower vBMD in both sexes (p < 0.001) but not with CSA. Following adjustment for demographic variables and CSA, MS-ES MFI remained predictive of vBMD (β = -0.408 to -0.157, p < 0.001).

CONCLUSION

We have demonstrated that, independent of CSA and demographic variables, MFI of the MF-ES muscles is predictive of lower lumbar spine vBMD in both sexes.

ADVANCES IN KNOWLEDGE

This is the first study to demonstrate that, independent of muscle size and demographic variables, MFI of the paraspinal MF-ES muscles is predictive of lower lumbar spine vBMD in both sexes.

Comparison of cross-sectional area and fat infiltration of suboccipital muscles between normal dogs and dogs with atlantoaxial instability

Background

Atlantoaxial instability (AAI) is primarily a congenital neurological disorder affecting young toy-breed dogs. So far, most studies have focused on bones and ligaments related to AAI, and there are no studies on the suboccipital muscles (SOMs) that occupy a large area from the occipital bone to C2 in dogs. This study evaluated the cross-sectional area (CSA) and fat infiltration of the SOMs using magnetic resonance imaging (MRI), specifically, T1-weighted images, in normal dogs (≤ 5 kg) and AAI dogs. The relationship between the severity of the neurological symptoms of AAI (group A and group B) and the values from MRI was also assessed.

Results

AAI dogs had significantly smaller CSA (P = 0.029) and greater fat infiltration (P = 0.044) of the SOMs compared to normal dogs. AAI dogs with mild neurological symptoms for a long period (group A) had greater fat infiltration than AAI dogs with severe neurological symptoms (group B) (P = 0.035).

Conclusions

The muscle changes are most likely due to spinal cord compression resulting from instability; however, the possibility that chronic changes of the muscle may play an additional role in maintaining stability in this region cannot be excluded. This study provides fundamental quantitative information of the SOMs in normal and AAI dogs.

The Role of Cervical Muscles Morphology in the Surgical Treatment of Degenerative Disc Disease: Clinical Correlations Based on Magnetic Resonance Imaging Studies

Cervical spine musculature still remains a less studied component of the cervical spine anatomical compartments, although it plays a significant role in the mobility of the head and the preservation of cervical spine alignment. The goal of this study was to extract any significant information from the literature regarding the role of cervical spine muscles morphology in the outcome of surgically treated patients for degenerative disc disease (DDD) based on preoperative magnetic resonance imaging (MRI) studies. Eleven clinical case series were found, from which four were prospective and seven were retrospective. Six studies were concentrated on anterior approaches and five studies on posterior approaches in the cervical spine. In posterior approaches aiming at the preservation of muscles attachments and overall less surgical manipulations, results on cervical lordosis, axial pain and patient’s functionality were found superior to traditional laminectomies. The study of cross-sectional areas (CSAs) of deep paraspinal muscles in the cervical spine could add significant information for the spine surgeon such as the prediction of adjacent level disease (ALD), fusion failure, axial pain persistence, postoperative cervical alignment and patient’s postoperative functionality. It seems that MRI studies focusing on muscle layers of the cervical spine could add significant information for the spinal surgeon regarding the final surgical outcome in terms of pain and function expression. Larger multicenter clinical studies are a necessity in defining the role of the muscle component of the cervical spine in the surgical treatment of DDD.

Comparison of paraspinal muscle degeneration and decompression effect between conventional open and minimal invasive approaches for posterior lumbar spine surgery

Laminotomy and transforaminal lumbar interbody fusion (TLIF) is usually used to treat unstable spinal stenosis. Minimally invasive surgery (MIS) can cause less muscle injury than conventional open surgery (COS). The purpose of this study was to compare the degree of postoperative fatty degeneration in the paraspinal muscles and the spinal decompression between COS and MIS based on MRI. Forty-six patients received laminotomy and TLIF (21 COS, 25 MIS) from February 2016 to January 2017 were included in this study. Lumbar MRI was performed within 3 months before surgery and 1 year after surgery to compare muscle-fat-index (MFI) change of the paraspinal muscles and the dural sac cross-sectional area (DSCAS) change. The average MFI change at L2–S1 erector spinae muscle was significantly greater in the COS group (27.37 ± 21.37% vs. 14.13 ± 19.19%, P = 0.044). A significant MFI change difference between the COS and MIS group was also found in the erector spinae muscle at the caudal adjacent level (54.47 ± 37.95% vs. 23.60 ± 31.59%, P = 0.016). DSCSA improvement was significantly greater in the COS group (128.15 ± 39.83 mm² vs. 78.15 ± 38.5 mm², P = 0.0005). COS is associated with more prominent fatty degeneration of the paraspinal muscles. Statically significant post-operative MFI change was only noted in erector spinae muscle at caudal adjacent level and L2–S1 mean global level. COS produces a greater area of decompression on follow up MRI than MIS with no statistical significance on clinical grounds.

Neck Muscle Changes Following Long-Duration Spaceflight

The effects of long-duration spaceflight on crewmember neck musculature have not been adequately studied. The purpose of this study was to evaluate the changes in the neck musculature on pre-flight and post-flight magnetic resonance imaging (MRI) examinations of six crewmembers on 4- to 6-month missions equipped with the advanced resistive exercise device (aRED). The MRI images were resliced to remove variations in spinal curvature, the cross-sectional area (CSA), and muscle fat infiltration (MFI) of neck musculature at the C1-C2, C4-C5, C7-T1, and T1-T2 intervertebral disc levels were measured bilaterally. Percent changes in the neck muscle CSA and fatty infiltration following spaceflight were calculated, and mixed models were used to assess significance of these changes. Crewmembers on missions equipped with the aRED experienced an average 25.1% increase in CSA for the trapezius muscle at C6-C7, an average 11.5% increase in CSA for the semispinalis capitis muscle at C4-C5, an average 9.0% increase in CSA for the sternocleidomastoid muscle at C4-C5, and an average 23.1% increase in CSA for the rhomboid minor at T1-T2. There were no significant changes in the CSA of the levator scapulae, splenius capitis, rectus capitis posterior major, scalenus anterior, scalenus posterior, scalenus medius, longissimus capitis, or obliquus capitis inferior muscles at the locations measured. None of the muscles analyzed experienced statistically significant changes in fatty infiltration with spaceflight. Our study indicates that long-duration spaceflight conditions are associated with preservation of CSA in most neck muscles and significant increases in the CSAs of the trapezius, semispinalis capitis, sternocleidomastoid, and rhomboid minor muscles. This may indicate that cervical muscles are not subjected to the same degradative effects microgravity imparts on the majority of muscles.

Application of MR-derived cross-sectional guideline of cervical spine muscles to validate neck surface electromyography placement

The importance of surface-EMG placement for development and interpretation of EMG-assisted biomechanical models is well established. Since MR has become a reliable noninvasive cervical spine musculoskeletal diagnostic tool, this investigation attempted to illustrate the anatomical relationships of individual cervical spine muscles with their paired surface-EMG electrodes. The secondary purpose of this investigation was to provide an MR cross-sectional pictorial and descriptive guideline of the cervical spine musculature. MR scans were performed on a healthy adult male subject from skull to manubrium of the sternum. Prior to scanning, MR safe markers were placed over neck muscles following surface EMG placement recommendations. Twenty-three neck muscles were traced manually in each of 267 scan slices. 3-D models of the neck musculoskeletal structure were constructed to aid with understanding the complex anatomy of the region as well as to identify correct EMG electrode locations and to identify muscles' curved lines-of-action. 3D models of the MR-safe markers were constructed relative to the target muscles. Based on the findings of this study, muscle palpation and bony landmarks can be used to effectively identify appropriate surface EMG electrode locations to record upper trapezius, middle trapezius, semispinalis capitis, splenius capitis, levator scapulae, scalenus, sternocleidomastoid and hyoid muscles activities.

Towards defining muscular regions of interest from axial magnetic resonance imaging with anatomical cross-reference: part II - cervical spine musculature

Background

It has been suggested that the quantification of paravertebral muscle composition and morphology (e.g. size/shape/structure) with magnetic resonance imaging (MRI) has diagnostic, prognostic, and therapeutic potential in contributing to overall musculoskeletal health. If this is to be realised, then consensus towards standardised MRI methods for measuring muscular size/shape/structure are crucial to allow the translation of such measurements towards management of, and hopefully improved health for, those with some musculoskeletal conditions. Following on from an original paper detailing methods for measuring muscles traversing the lumbar spine, we propose new methods based on anatomical cross-reference that strive towards standardising MRI-based quantification of anterior and posterior cervical spine muscle composition.

Methods

In this descriptive technical advance paper we expand our methods from the lumbar spine by providing a detailed examination of regional cervical spine muscle morphology, followed by a comprehensive description of the proposed technique defining muscle ROI from axial MRI. Cross-referencing cervical musculature and vertebral anatomy includes an innovative comparison between axial E12 sheet-plastinates derived from cadaveric material to a series of axial MRIs detailing commonly used sequences. These images are shown at different cervical levels to illustrate differences in regional morphology. The method for defining ROI for both anterior (scalenes group, sternocleidomastoid, longus colli, longus capitis) and posterior (multifidus, semispinalis cervicis, semispinalis capitis, splenius capitis) cervical muscles is then described and discussed in relation to existing literature.

Results

A series of steps towards standardising the quantification of cervical spine muscle quality are described, with concentration on the measurement of muscle volume and fatty infiltration (MFI). We offer recommendations for imaging parameters that should additionally inform a priori decisions when planning investigations of cervical muscle tissues with MRI.

Conclusions

The proposed method provides an option rather than a final position for quantifying cervical spine muscle composition and morphology using MRI. We intend to stimulate discussion towards establishing measurement consensus whereby data-pooling and meaningful comparisons between imaging studies (primarily MRI) investigating cervical muscle quality becomes available and the norm.

Cross-sectional area and fat content in dachshund epaxial muscles: an MRI and CT reliability study

MRI and CT are frequently used to diagnose spinal diseases in dogs. These modalities have detected epaxial muscle degeneration in dachshunds with intervertebral disc herniation. However, research on the reliability of epaxial muscular measurements is limited in veterinary medicine. The aims of the study were to assess the intrarater and inter-rater reliability of epaxial muscle cross-sectional area (CSA) and fat content measurements on MRI and CT images in dachshunds, and to compare the CSA measurement between the two modalities. MRI and CT images of 10 healthy dachshunds were evaluated. Two blinded observers assessed MRI CSA, MRI fat content, CT CSA and CT muscle attenuation of three thoracolumbar epaxial muscles using OsiriX. The results showed ‘substantial’ to ‘almost perfect’ intrarater reliability (intraclass correlation coefficient (ICC) 0.828–0.998) and inter-rater reliability (ICC 0.685–0.854) for all variables. When individual spinal segments were analysed, the intrarater and inter-rater reliability decreased and the confidence intervals increased. There was positive correlation (r= 0.719–0.841, P=0.001) and high agreement (0.824–0.894) for the measured CSA between MRI and CT. Epaxial muscle CSA and fat content can be reliably measured on MRI and CT, bearing in mind that measurement of certain segments requires adequate training.

Quantitative Magnetic Resonance Imaging Analysis of the Cervical Spine Extensor Muscles: Intrarater and Interrater Reliability of a Novice and an Experienced Rater

Study Design

Reliability study.

Purpose

To examine the reliability of novice and experienced raters for measurements of the size and composition of the cervical extensor muscles using a thresholding technique.

Overview of Literature

Although some authors have reported on the dependability of magnetic resonance imaging (MRI) measurements of the cervical muscles, there remains some variability regarding intrarater and interrater reliabilities, and few studies have examined the associated measurement error. Whether the rater's experience noticeably influences the reliability and precision of such measurements has also not been examined.

Methods

A sample of 10 patients with cervical pathologies was selected. Muscle cross-sectional area (CSA), functional cross-sectional area (FCSA), and signal intensity of the cervical extensor muscles were acquired from axial T2-weighted MRIs by a novice and an experienced rater. All measurements were obtained twice, at least 5 days apart, while the raters were blinded to all earlier measurements.

Results

Interrater reliability estimates (intraclass correlation coefficients) varied between 0.84 and 0.99 for the novice rater and between 0.94 and 0.99 for the experienced rater, indicating excellent reliability. The standard error of measurement for the novice rater was, however, noticeably higher for all cervical muscle measurements. Most of the interrater estimates showed excellent agreement with the exception of CSA measurement of the semispinalis cervicis at C4-C7 and FCSA measurement of the multifidus and semispinalis cervicis at C4-C7, which showed poor interrater reliability.

Conclusions

The proposed method of investigating cervical muscle measurements was highly reliable; however, novice raters should receive adequate training before using this method for diagnostic, research, and clinical purposes.

Evidence for cervical muscle morphometric changes on magnetic resonance images after whiplash: A systematic review and meta-analysis

INTRODUCTION

Morphometric changes to cervical musculature in whiplash associated disorder have been reported in several studies with varying results. However, the evidence is not clear because only a limited number of cohorts have been studied and one cohort has been reported in multiple publications. The aim of this study was to assess the evidence for cervical muscle morphometric changes on magnetic resonance (MR) images after whiplash using a systematic review with meta-analysis.

MATERIALS AND METHODS

PubMed, MEDLINE and Cochrane Library were searched without language restriction using combinations of the MeSH terms "muscles", "whiplash injuries", and "magnetic resonance imaging". Studies of acute and chronic whiplash were included if they compared whiplash and control cervical spine muscle morphometry measurements from MR images. The search identified 380 studies. After screening, eight studies describing five cohorts (one acute, three chronic, one both acute and chronic) met the inclusion criteria. Participant characteristics and outcome measures were extracted using a standard extraction format. Quality of eligible studies was assessed using the Newcastle-Ottawa Scale. Muscle cross-sectional area (CSA) and fat infiltrate (MFI) for acute and chronic whiplash cohorts were compared using mean difference and 95% confidence intervals. Meta-analysis models were created when data from more than two eligible cohorts was available, using inverse-variance random-effects models (RevMan5 version 5.3.5).

RESULTS

Quality assessment was uniformly good but only two studies blinded the assessor. Analysis of the acute cohorts revealed no consensus with respect to CSA. MFI was not measured in the acute cohorts. Analysis of the chronic cohorts revealed CSA is probably increased in some muscles after whiplash but there is insufficient evidence to confirm whether MFI is also increased. Because the available data were limited, meta-analyses of only multifidus were performed. In chronic whiplash multifidus CSA was significantly increased at C5 (Z = 3.51, p < 0.01) and C6 (Z = 2.66, p < 0.01); and MFI was significantly increased at C7 only (Z = 2.52, p < 0.01) but the heterogeneity was unacceptably high (I² = 83%).

CONCLUSIONS

The strength of the evidence for cervical muscle morphometric changes on MR images after whiplash is inconsistent for CSA and MFI. Future study designs should be standardised with quantification of three-dimensional muscle morphometry.

Morphological classification and comparison of suboccipital muscle fiber characteristics

In an attempt to clarify the function of the suboccipital muscles, we performed morphological observation of the suboccipital muscles for variations in the muscle belly and compared the morphology of their muscle fibers in terms of cross-sectional area by immunostaining with anti-myosin heavy chain antibodies. The cadavers of 25 Japanese individuals were used: 22 for morphological examinations and three for histological examinations. Among samples of the rectus capitis posterior major muscle (RCPma) and rectus capitis posterior minor muscle (RCPmi), 86.4% had a typical muscle appearance with a single belly, and 13.6% had an anomalous morphology. None of the samples of the obliquus capitis superior (OCS) or obliquus capitis inferior (OCI) muscles had an anomalous appearance. Measurement of cross-sectional area revealed that fast-twitch muscle fibers in the RCPma and OCI had a significantly greater cross-sectional area than those of the RCPmi and OCS. The cross-sectional area of intermediate muscle fibers was also significantly greater in the OCS than in the RCPma, RCPmi, and OCI. The cross-sectional area of slow-twitch muscle fibers was significantly greater in the OCS than in the RCPma, RCPmi, and OCI, and the RCPmi showed a significantly greater cross-sectional area for slow-twitch muscle fibers than did the RCPma, and OCI. Our findings indicate that the RCPmi and OCS exert a greater force than the RCPma and OCI, and act as anti-gravity agonist muscles of the head. Prolonged head extension in individuals with anomalous suboccipital muscle groups could result in dysfunction due to undue stress.

Muscle Atrophy Measurement as Assessment Method for Low Back Pain Patients

Low back pain is one of the most common pain disorders defined as pain, muscle tension, or stiffness localized below the costal margin and above the inferior gluteal folds, sometimes with accompanying leg pain. The meaning of the symptomatic atrophy of paraspinal muscles and some pelvic muscles has been proved. Nowadays, a need for new diagnostic tools for specific examination of low back pain patients is posited, and it has been proposed that magnetic resonance imaging assessment toward muscle atrophy may provide some additional information enabling the subclassification of that group of patients.

Reliability of histographic analysis for paraspinal muscle degeneration in patients with unilateral back pain using magnetic resonance imaging

BACKGROUND

Mixed use of T1- or T2-weighted magnetic resonance imaging (MRI) in histographic analysis has impeded cross-reference of studies on fatty degeneration of muscles in patients with back pain.

OBJECTIVE

The current study aimed to establish the measurement reliability of histographic analysis for normal and painful paraspinal muscles between T1- and T2-weighted MRI.

METHODS

T1- and T2-weighted MRI at the L4-5 level were performed in 31 patients with unilateral back pain. Two raters conducted the histographic analysis on 2 separate occasions. Multifidus, erector spinae, and psoas major muscles were assessed on both normal and painful sides.

RESULTS

Intra- and interrater reliability of the parameters were generally excellent for both T1- (intrarater: 0.83 ± 0.13 and interrater: 0.93 ± 0.08) and T2-weighted images (intrarater: 0.93 ± 0.12 and interrater: 0.92 ± 0.12). Histogram width was fair to good for both kinds of image. Intraclass correlation coefficients were similar between painful and normal sides.

CONCLUSIONS

The evidence that most histographic analysis parameters had excellent reliability for both T1- and T2-weighted images allows for cross-reference of the results between the two kinds of image. Moreover, the results of this study support the availability of histographic analysis for assessment of fatty degeneration in patients with back pain.

Fat Replacement of Paraspinal Muscles with Aging in Healthy Adults

PURPOSE

The aims of this study were to investigate the age-related changes in fatty replacement and cross-sectional area (CSA) of cervical, thoracic, and lumbar paraspinal muscles versus leg muscles in healthy adults and to test for association between muscle fat fraction and lifestyle factors.

METHODS

Fifty-three healthy adults (24-76 yr) were included. Dixon magnetic resonance imaging technique was used to determine CSA and to quantify the fat fraction of paraspinal and leg muscles. Muscle CSA and fat fractions were tested for association with age and muscle strength. The fat fractions were also tested for association with sex, body mass index (BMI), physical activity, and lower back pain.

RESULTS

Both paraspinal and leg fat fractions correlated directly with age (P < 0.0001). At all ages, fat fraction was higher in paraspinal than leg muscles. The age-related increase in fat fraction was higher in paraspinal muscles than leg muscles (P < 0.0001). The CSA of the muscles did not correlate with age. Knee extension strength correlated with fat fraction (P < 0.05), and the muscle strength of hip muscles, thigh muscles, and anterior calf muscles correlated with CSA (P < 0.05). Sex was associated with lumbar paraspinal fat fraction (P < 0.05) and BMI with thigh fat fraction (P < 0.001). There was no association between fat fraction and physical activity or lower back pain.

CONCLUSION

The paraspinal muscles were more susceptible to age-related changes than leg muscles. Further, men had significantly lower fat fractions in lumbar paraspinal muscles, and BMI was positively associated with thigh, but not paraspinal, fat fraction.

Structural changes of the cervical muscles in elder women with cervicogenic headache

BACKGROUND

Evidence suggests that cervicogenic headache is associated with increasing age. Cervical musculoskeletal impairments are common features in individuals with cervicogenic headache. There is some suggestion that the structure (size and fatty infiltration) of neck muscle may factor in or contribute to these impairments.

OBJECTIVE

To investigate relative cross sectional areas (rCSAs) and fatty infiltrate in the cervical muscles in elders with cervicogenic headache compared to controls.

METHODS

Fourteen elder women with cervicogenic headache and 14 controls participated in the study. The rCSAs and fat infiltration were measured for the rectus capitis posterior major, rectus capitis posterior minor, multifidus, semispinalis capitis, splenius capitis, longus capitis/colli, and sternocleidomastoid.

RESULTS

Elder women with cervicogenic headache had significantly reduced rCSAs of the rectus capitis posterior major and multifidus muscles compared to controls (p < 0.05). Larger amounts of fat infiltrates were also observed in the rectus capitis posterior major and minor and splenius capitis muscles in the cervicogenic headache group (p < 0.05). There were no changes in the size and fat infiltrate in the cervical flexor muscles (p > 0.05).

CONCLUSION

The study demonstrated muscle atrophy with increased fatty infiltration in regionally select muscles of the upper and segmental cervical spine in older women with cervicogenic headache. While such changes and their influence on clinical symptoms are unknown, they may have management implications. Future research investigations are required to determine whether such alterations could be modified with specific exercise and modifications to daily living to positively influence clinical symptoms.

Anterior Thigh Tissue Thickness Measured Using Ultrasound Imaging in Older Recreational Female Golfers and Sedentary Controls

Physical activity is vital for the prevention of sarcopenia and frailty. The training effects of recreational golf on muscle function in older people are unknown. The present study examined quadriceps muscle and subcutaneous fat thickness in 66 older females. Thirty-one golfers (mean age 69.1 years, standard deviation ±3.4) were compared with 35 less active non-golfers (73.4 ± 4.2 years). Images of the dominant anterior thigh were obtained using real-time B-mode ultrasound imaging. Thickness of muscle (rectus femoris, vastus intermedius, and intermuscular fascia) and subcutaneous tissue (fat and perimuscular fascia) was measured, and percentage contributions calculated. Muscle thickness was significantly greater (p < 0.001) in golfers (mean 2.78 cm ± 0.73 cm) than non-golfers (2.18 cm ± 0.55 cm). Mean percentage contribution of muscle and non-contractile tissue was 64% ± 9% and 36% ± 9%, respectively, in golfers, compared to 58% ± 8% and 42% ± 8% in non-golfers (p = 0.013). Multiple linear regression analysis, controlling for age and BMI, showed that golfers still had higher total anterior thigh thickness (regression parameter for non-golfers B = −0.984, p = 0.004) and higher muscle thickness (B = −0.619, p = 0.002). This study indicates an association between recreational golf and greater relative thigh muscle thickness and lower subcutaneous fat than in less active controls. Training effects need to be examined in prospective controlled trials in males and females in different age groups.

Correlation between chronic headaches and the rectus capitis posterior minor muscle: A comparative analysis of cross-sectional trail

Objective We aimed to investigate the morphological changes and potential correlation between chronic headaches and the rectus capitis posterior minor muscle (RCPmi). Methods Comparison of RCPmi between patients with chronic headaches and healthy adult volunteers were collected using magnetic resonance imaging (MRI) and Mimics software. Results Among the 235 MRI images analyzed, the data between the two groups were considered statistically significant. The number of males was larger than that of females ( p < 0.001) and the headache group showed greater hypertrophy than the control group in both males ( p < 0.001) and females ( p = 0.001). Conclusions Chronic headaches were correlated with the RCPmi. Patients with chronic headaches suffered from more obvious hypertrophy than that of the control group. Additionally, it was supposed that RCPmi hypertrophy may be one pathogenesis of the chronic headaches.

In vivo MRI features of spinal muscles in the ovine model

Background

Muscle fatty infiltration (MFI) has been identified in patients with spinal pain using magnetic resonance imaging (MRI). Even though sheep are a commonly used animal model for the human spine, comparative sheep MFI data from MRI is not available. Determining MFI in sheep spinal muscles using acquisition protocols commonly used in man will identify the applicability of this approach in future sheep model studies, such that the effects of spinal interventions on muscle can be assessed prior to their use in a human (clinical) population.

Objective

To quantify ovine lumbar spine MFI using three-dimensional two-point Dixon and T1-weighted sequences.

Methods

T1-weighted and Dixon lumbar spine axial sequences were collected in 14 healthy Austrian mountain sheep using a 1.5-T MRI. At each vertebrae, the region of interest of psoas major and minor (PS), multifidus (M), and longissimus (L) were identified. To determine MFI from the T1-weighted images, the mean pixel intensity (MPI) was calculated as a percentage of subcutaneous or intermuscular fat. For the Dixon images, fat sequence MPI was calculated as a percentage of the summed fat and water sequence MPIs. Spinal degeneration was graded and correlated to MFI. Dixon MFI was compared to T1-weighted MFI obtained from subcutaneous and intermuscular fat.

Results

For every muscle, T1-weighted MFI calculated using subcutaneous fat scored significantly lower than Dixon MFI and T1-weighted MFI calculated using intermuscular fat (p < 0.001). There were no significant MFI differences between T1-weighted images calculated using intermuscular fat and Dixon images for M and L (p > 0.05), although significant differences were found for PS.

Conclusion

In sheep, Dixon sequences provide an acceptable comparison to T1-weighted sequences for lumbar extensor MFI based on intermuscular fat. However, compared to the human literature, ovine lumbar musculature contains greater MFI, making interspecies comparisons more complex.

Magnetic resonance imaging atlas of the cervical spine musculature

The anatomy of the cervical spine musculature visible on magnetic resonance (MR) images is poorly described in the literature. However, the correct identification of individual muscles is clinically important because certain conditions of the cervical spine, for example whiplash associated disorders, idiopathic neck pain, cervical nerve root avulsion and cervical spondylotic myelopathy, are associated with different morphological changes in specific muscles visible on MR images. Knowledge of the precise structure of different cervical spine muscles is crucial when comparisons with the contralateral side or with normal are required for accurate description of imaging pathology, management and assessment of treatment efficacy. However, learning the intricate arrangement of 27 muscles is challenging. A multi-level cross-sectional depiction combined with three-dimensional reconstructions could facilitate the understanding of this anatomically complex area. This paper presents a comprehensive series of labeled axial MR images from one individual and serves as a reference atlas of the cervical spine musculature to guide clinicians, researchers, and anatomists in the accurate identification of these muscles on MR imaging. Clin. Anat. 29:643-659, 2016. © 2016 Wiley Periodicals, Inc.

Greater Cervical Muscle Fat Infiltration Evaluated by Magnetic Resonance Imaging is Associated With Poor Postural Stability in Patients With Cervical Spondylotic Radiculopathy

STUDY DESIGN

A population-based, cross-sectional study.

OBJECTIVE

The aim of this study was to quantitatively evaluate the relationship between static postural stability and fat infiltration within cervical multifidus muscle in patients with cervical spondylotic radiculopathy (CSR).

SUMMARY OF BACKGROUND DATA

CSR causes denervation by compression of nerve roots. This denervation is detected by fatty infiltration or results in fatty infiltration within muscles. Proprioceptive information in cervical multifidus muscle plays an important role in coordinated movement of postural stability; however, there have been few studies evaluating the relationship between postural stability and fat infiltration within cervical multifidus muscle among CSR patients.

METHODS

Sixteen CSR patients with C6 injuries and 25 age-matched healthy controls underwent magnetic resonance images to examine bilateral cervical multifidus muscle. For evaluation of fat within muscle, a muscle fat index (MFI) was calculated by using both measurement of cervical multifidus muscle and intermuscular fat. Participants' postural stability at upright position with eyes-opened and eyes-closed for 60 seconds was examined by a platform. Two parameters, the total length and the area of the center of pressure (COP), were used for evaluation.

RESULTS

The CSR group showed significantly poorer postural stability than the control group (eyes-opened the total length; P < 0.05, eyes-closed the total length; P < 0.05, eyes-closed the area; P < 0.05). There were significant group differences at C4, C5, and C6 MFI (P < 0.05). In the CSR group, a correlation analysis demonstrated that the age, C4, C5, and C6 MFI values were significantly associated with the eyes-closed the total length of the COP (P < 0.05).

CONCLUSIONS

Fat infiltration within muscle could lead to inhibition of normal activity of musculature. The present study suggests that fat within cervical multifidus muscle could directly cause postural instability in static standing, even though the proprioceptive information has normal lower limbs.

MRI assessment of paraspinal muscles in patients with acute and chronic unilateral low back pain

OBJECTIVE

To investigate the changes in paraspinal muscle cross-sectional area (CSA) and composition, using the digital data from lumbar spine MRIs of patients with acute and chronic low back pain (LBP).

METHODS

In total, 178 patients with unilateral LBP who had lumbar MRI examination were recruited. The data were obtained by a retrospective documentation audit. The CSAs and mean signal intensities of the bilateral paraspinal muscles [psoas major (PM), quadratus lumborum, multifidus (MF) and erector spinae (ES)] were measured, and the percentage of fat infiltration was calculated. The data between the painful side and non-painful side were compared, and between-group comparisons were tested. 42 patients with chronic unilateral LBP could indicate the problem level, and the CSA and mean signal intensity of the MF muscle were analysed at the problem level, and one vertebral above and one vertebral level below the problem level.

RESULTS

The CSAs of the PM and ES muscles were significantly decreased in the acute LBP group, while in the chronic LBP group, significant reduction in CSA was found in the MF and ES muscles on the painful side compared with the non-painful side. The mean signal intensity and fat content of the ES muscle on the painful side in the chronic LBP group was significantly higher than that on the painful side in the acute LBP group. The significant decrease of CSA in the MF muscle was found at multiple levels on the painful side.

CONCLUSION

The present findings show that there is selective ipsilateral atrophy of paraspinal muscles, specific to the symptomatic side, in patients with acute and chronic LBP. The reduction of the muscle CSA and increased fatty infiltration occurred synchronously, and the extent of change is significantly greater in chronic LBP in the ES muscle. Atrophy of the MF muscle appears to be at multiple levels but side specific in relation to symptoms in patients with chronic LBP, and the decreased muscle CSA may occur prior to fatty infiltration.

ADVANCES IN KNOWLEDGE

There are specific paraspinal muscles undergoing atrophy and fatty infiltration in patients with acute and chronic LBP on the symptomatic side. The CSA of the MF muscle decreased at multiple levels on the symptomatic side in patients with chronic unilateral LBP, which may occur prior to fatty infiltration.

Age and side-related morphometric MRI evaluation of trunk muscles in people without back pain

This study evaluated lumbar spine muscle volume and Muscle Fatty Infiltrate (MFI) across two age groups of healthy adults. Twenty-four participants (young group - YG: age 18-25, n = 12; mature group - MG: age 45-60, n = 12) without low back pain underwent T1-weighted axial MRI. Muscle volume and MFI were obtained from the left and right lumbar erector spinae (ES), multifidus (M), rectus abdominis (RA) and psoas (PS) muscles. For MFI, mean pixel intensity (MPI) of muscles was reported as a percentage of subcutaneous fat MPI. Within-group comparison of left and right side muscle volume was not significantly different in the YG. In the MG, right RA and ES were significantly smaller than left (RA p = 0.049; ES p = 0.03). In both groups, left PS, M and ES MFI was significantly smaller compared to the right side and left RA MFI was significantly greater compared to right side (all p ≤ 0.001). For M volume, 81.7-84.6% of variance was explained by age, height and Body Mass Index (BMI). For ES volume, 81.6-82.8% of variance was explained by height and BMI. Age explained 18.1%-36.0% of variance in M and ES right MFI. Therefore, age and BMI are relevant factors for extensor muscle volume, but not for flexor muscle volume. Also, age significantly influences MFI for right-sided extensors only. The age effect is apparently independent of full subjective back functionality. For future spinal muscle research, the side-and muscle-specific effect of age on muscle morphology should be considered.

Quantification of cervical spine muscle fat: a comparison between T1-weighted and multi-echo gradient echo imaging using a variable projection algorithm (VARPRO)

Background

Previous data using T1-weighted MRI demonstrated neck muscle fat infiltration (MFI) in patients with poor functional recovery following whiplash. Such findings do not occur in those with milder symptoms of whiplash, chronic non-traumatic neck pain or healthy controls, suggesting traumatic factors play a role. Muscle degeneration could potentially represent a quantifiable marker of poor recovery, but the temporal constraints of running a T1-weighted sequence and performing the subsequent analysis for muscle fat may be a barrier for clinical translation. The purpose of this preliminary study was to evaluate, quantify and compare MFI for the cervical multifidus muscles with T1-weighted imaging and a more rapid quantitative 3D multi-echo gradient echo (GRE) Dixon based method in healthy subjects.

Methods

5 asymptomatic participants with no history of neck pain underwent cervical spine MRI with a Siemens 3 Tesla system. The muscle and fat signal intensities on axial spin-echo T1-weighted images were quantitatively classified for the cervical multifidii from C3-C7, bilaterally. Additional axial GRE Dixon based data for fat and water quantification were used for comparison via paired t-tests. Inter-tester reliability for fat and water measures with GRE images were examined using 1) Pearson’s Intra-class correlation coefficient 2) Bland-Altman Plots and 3) Lin’s-Concordance Coefficient. P < 0.05 was used to indicate significance.

Results

Total mean (SD) MFI (C3-C7) for the multifidii obtained with T1-weighted imaging and GRE were 18.4% (3.3) (range 14-22%) and 18.8% (2.9) (range 15-22%), respectively. The Pearson correlation coefficients for inter-tester reliability on the GRE sequences for the C3-C7 multifidii ranged from .83 - .99, indicating high levels of agreement with segmental MFI measures. Bland-Altman Plots revealed all data points were within 2 SDs and concordance was established between 2-blinded raters, suggesting good agreement between two raters measuring fat and water with GRE imaging.

Conclusions

Results of this preliminary study demonstrate reliability between 2 raters of varying experience for MRI analysis of MFI with 3D GRE MRI. The quantification of MFI for healthy cervical musculature is comparable to T1-weighted images. Inclusion of larger samples of symptomatic data and histological comparison with the reference standard biopsy is warranted.

Skeletal muscle disease: patterns of MRI appearances

Although the presumptive diagnosis of skeletal muscle disease (myopathy) may be made on the basis of clinical-radiological correlation in many cases, muscle biopsy remains the cornerstone of diagnosis. Myopathy is suspected when patients complain that the involved muscle is painful and tender, when they experience difficulty performing tasks that require muscle strength or when they develop various systemic manifestations. Because the cause of musculoskeletal pain may be difficult to determine clinically in many cases, MRI is increasingly utilised to assess the anatomical location, extent and severity of several pathological conditions affecting muscle. Infectious, inflammatory, traumatic, neurological, neoplastic and iatrogenic conditions can cause abnormal signal intensity on MRI. Although diverse, some diseases have similar MRI appearances, whereas others present distinct patterns of signal intensity abnormality. In general, alterations in muscle signal intensity fall into one of three cardinal patterns: muscle oedema, fatty infiltration and mass lesion. Because some of the muscular disorders may require medical or surgical treatment, correct diagnosis is essential. In this regard, MRI features, when correlated with clinical and laboratory findings as well as findings from other methods such as electromyography, may facilitate correct diagnosis. This article will review and illustrate the spectrum of MRI appearances in several primary and systemic disorders affecting muscle, both common and uncommon. The aim of this article is to provide radiologists and clinicians with a collective, yet succinct and useful, guide to a wide array of myopathies.

Cervical muscle area measurements in whiplash patients: Acute, 3, and 6 months of follow-up

PURPOSE

To investigate the role of the cervical spine muscles in whiplash injury. We hypothesized that (i) cervical muscle hypotrophy would be evident after a 6-month follow-up and, (ii) cervical muscle hypotrophy would correlate with symptom persistence probably related to pain or inactivity.

MATERIALS AND METHODS

Ninety symptomatic patients (48 females) were recruited from our emergency department and examined within 48 h, and at 3, and 6 months after a motor vehicle accident. MRI cross-sectional muscle area (CSA) measurements were performed bilaterally of the cervical extensor and sternocleidomastoid muscles using transverse STIR (Short Tau inversion Recovery) sequences at the C2 (deep and total dorsal cervical extensor muscles), C4 (sternocleidomastoid muscles) and C5 (deep and total dorsal cervical extensor muscles) levels. Two blinded raters independently performed the measurements at each time point. First, CSA changes over time were analyzed and, second, CSAs were correlated with clinical outcomes (EuroQuol, Whiplash Disability Score, neck pain intensity [VAS], cervical spine mobility).

RESULTS

There was a high agreement of CSA measurements between the two raters. Women consistently had smaller CSAs than men. There were no significant changes of CSAs over time at any of the three levels. There were no consistent significant correlations of CSA values with the clinical scores at all time points except with the body mass index.

CONCLUSION

Our results do not support a major role of cervical muscle volume in the genesis of symptoms after whiplash injury.

Increased intramuscular fatty infiltration without differences in lumbar muscle cross-sectional area during remission of unilateral recurrent low back pain

Lumbar muscle degeneration is a common feature in non-specific low back pain (LBP). It is hypothesized that degenerated muscles might compromise spinal stability and lead to further injury/pain. However, little is known about lumbar muscle morphometry after resolution of LBP. Therefore, this study investigated the extent of lumbar muscle atrophy and fatty infiltration in individuals who are at risk for a recurrence of LBP. Thirteen participants in remission of unilateral recurrent LBP were compared to 13 healthy controls, comparable for age, weight, length and level of physical activity. Total, lean muscle and fat cross-sectional area (CSA) of lumbar multifidus (MF), erector spinae (ES) and psoas (PS) were investigated on T1-weighted Magnetic Resonance Imaging (MRI), bilaterally and at 3 lumbar levels (L3 upper, L4 upper and L4 lower endplate). In addition, a muscle-fat-index (MFI) was calculated reflecting the amount of fatty infiltration in lean muscle tissue. No significant differences for total, lean muscle and fat CSA were found between people in remission of recurrent LBP and the control group. Conversely, MFI was increased bilaterally at the 2 lowest lumbar levels. There were no differences between the previously painful and non-painful side of the LBP group for any of the parameters. These results show a generalized increase in intramuscular fatty infiltration in lean muscle tissue in the absence of macroscopical signs of muscle degeneration after resolution of LBP. These findings reflect a decreased muscle quality, but not quantity, and might indicate a pathophysiological mechanism contributing to recurrence of LBP.

Analysis of Relationship between Paraspinal Muscle Fatty Degeneration and Cervical Spine Motion Using Kinetic Magnetic Resonance Imaging

The alignment and mobility of the cervical spine is influenced by factors related to the vertebral bodies, intervertebral discs, ligaments, facet joints, and muscles. Few reports have described the role played by the paraspinal muscles in cervical spine mobility. In this study, we investigate the relationship between fatty degeneration of the paraspinal muscles and cervical motion as assessed with kinetic magnetic resonance imaging (kMRI). One hundred eighty-eight symptomatic patients underwent cervical kMRI in neutral, flexion, and extension positions. We quantified cervical paraspinal muscle fatty infiltration and measured angular variation and translational motion at each cervical level, and the global Cobb angle. Cervical paraspinal muscle fatty degeneration demonstrated a pattern in which C3 and C7 had significantly more fatty infiltration than C4, C5, and C6. Additionally, when the normal group was compared with the fatty degeneration group with respect to angular variation, translational motion, and Cobb angle, no significant differences were found except in angular variation at the C3-C4 level. In conclusion, we found a significantly larger quantity of fatty degeneration in the paraspinal muscles at C3 and C7 than the middle cervical levels. Also, we demonstrate that fatty degeneration does not significantly affect cervical lordotic alignment or mobility characteristics.

Connection between the spinal dura mater and suboccipital musculature: evidence for the myodural bridge and a route for its dissection--a review

A connective tissue link between the spinal dura mater and the rectus capitis posterior minor muscle was first described in 1995 and has since been readily demonstrated via dissection, magnetic resonance imaging, and plastinated cross-sections of the upper cervical region (Hack et al. [1995] Spine 20:2484-2486). This structure, the so-called "myodural bridge," has yet to be included in any of the American anatomy textbooks or dissection guides commonly used in medical education. This direct anatomic link between the musculoskeletal system and the dura mater has important ramifications for the treatment of chronic cervicogenic headache. This article summarizes the anatomic and clinical research literature related to this structure and provides a simple approach to dissect the myodural bridge and its attachment to the posterior atlanto-occipital membrane/spinal dura mater complex and summarizes the case for its possible inclusion in medical anatomy curricula.

Cervical muscle area measurements in acute whiplash patients and controls

PURPOSE

To quantitatively compare the muscle cross-sectional areas (CSAs) of the cervical muscles in symptomatic acute whiplash patients versus healthy controls. We hypothesized, that symptomatic whiplash patients have smaller cervical muscle CSAs than matched controls and that smaller cervical muscle CSAs in women might explain that women more frequently are symptomatic after whiplash injury than men.

MATERIALS AND METHODS

Prospective controlled study. Thirty-eight consecutive acute whiplash patients were examined within 48 h after a motor vehicle accident and 38 healthy age- and sex-matched controls, each half female, half male, were examined with the same protocol. MRI CSA measurements were performed of the deep and total cervical extensor muscles as well as the sternocleidomastoid muscles using transversal STIR (Short T1 Inversion Recovery) sequences on level C2, C4, and C5 by two blinded raters. Clinical symptoms were assessed with patient questionnaires (EuroQuol 5D, Specific Whiplash Questionnaire, head- and neck pain intensity [VAS]).

RESULTS

Agreement of measurements between the two raters was high (intraclass correlation 0.52 to 0.85 for the different levels). No significant difference in age and body mass index were seen between patients and controls and the distribution of genders across groups was identical. There were no significant differences between patients and controls for all CSAs. Women had consistently smaller CSAs than men. The CSAs showed no significant correlation with the pain intensity of neck pain and headache but a consistent tendency of less neck pain and more headache with greater CSAs.

CONCLUSION

This small study provides no evidence that subjects with smaller CSAs of cervical extensor muscles have a higher risk in developing symptoms after a whiplash injury and confirms smaller CSA in women.

Diffusion-weighted magnetic resonance imaging for the healthy cervical multifidus: a potential method for studying neck muscle physiology following spinal trauma

STUDY DESIGN

Cross-sectional.

OBJECTIVE

To develop a new magnetic resonance imaging (MRI) measure for the diffusive properties of the healthy cervical multifidus and to determine the interrater and intrarater reliability of the measurement.

BACKGROUND

Diffusion-weighted MRI, via calculation of the apparent diffusion coefficient (ADC), provides a representation of microscopic movements of water molecules in human tissues and may be useful to assess structural changes in neck muscle, as has been observed following whiplash. The optimal imaging parameters, however, have not been established.

METHODS

A diffusion-weighted MRI measure was developed, and, for the basic examination, the right cervical multifidus muscle at the C5 level was studied. A total of 6 asymptomatic volunteer individuals (3 females and 3 males) underwent a single diffusion-weighted MRI scan. Interrater and intrarater agreement was evaluated using Bland-Altman plots and intraclass correlation coefficients.

RESULTS

Mean ADCb0-b50 and ADCb50-250 were significantly different from one another (P=.03). The plots confirmed the agreement of raters for ADC of the right cervical multifidus at C5.

CONCLUSIONS

A quantitative and reliable diffusion-weighted MRI measure of cervical multifidus ADC has been described. There appears to be a fast and slow component ADC for the healthy multifidus, suggesting changes in extracellular and intracellular volume. Further comparative study is needed to quantify ADCs in the neck muscles in patients with traumatic whiplash.

Magnetic resonance imaging findings of fatty infiltrate in the cervical flexors in chronic whiplash

STUDY DESIGN

Retrospective investigation of muscle changes in patients suffering from chronic whiplash-associated disorders (WAD).

OBJECTIVES

To quantitatively compare the presence of muscle alterations (fatty infiltrate [MFI] and cross-sectional area [CSA]) in the anterior musculature of the cervical spine in a cohort of chronic whiplash patients (WAD II) and healthy control subjects across muscle and cervical segmental level.

SUMMARY OF BACKGROUND DATA

Magnetic resonance imaging can be regarded as the gold standard for muscle imaging. There is little knowledge about in vivo features of anterior neck muscles in patients suffering from chronic WAD and how muscle structure differs across the factors of muscle, vertebral level, age, self-reported pain and disability, body mass index, and duration of symptoms.

METHODS

Reliable magnetic resonance imaging measures for MFI and CSA were performed for the anterior cervical muscles bilaterally in 109 female subjects (78 WAD, 31 healthy control; 18-45 years, 3 months to 3 years postinjury). The measures were performed on all subjects for the longus capitis and colli and the sternocleidomastoid muscles.

RESULTS

The WAD subjects had significantly larger MFI and CSA for the anterior muscles compared to healthy control subjects (all P < 0.0001). In addition, the amount of MFI varied by both cervical level and muscle, with the longus capitis/colli having the largest amount of fatty infiltrates at the C2-C3 level (P < 0.0001). MFI was inversely related to age, self-reported pain/disability, and body mass index but directly proportional to duration of symptoms.

CONCLUSION

There is significantly greater MFI and CSA in the anterior neck muscles, especially in the deeper longus capitis/colli muscles, in subjects with chronic WAD when compared to healthy controls. Future studies are required to investigate the relationships between muscular morphometry and symptoms in patients suffering from acute and chronic WAD.

MRI analysis of muscle/fat index of the superficial and deep neck muscles in an asymptomatic cohort

All muscles of the neck have a role in motion and postural control of the cervical region. The aim of this study was to investigate the difference in muscle/fat index between (1) cervical flexors and extensors and (2) deep and superficial neck muscles. Twenty-six healthy subjects participated in the study. Magnetic resonance imaging (MRI) was used to quantify muscle fat indices in different cervical flexor and extensor muscles at the C4-C5 level. Overall, the ventral muscles had a significantly lower fat content compared with the dorsal muscles (P < or = 0.001). For the cervical extensors, significant differences between the muscle/fat index of the deep and superficial muscles were found (P < or = 0.001). For the cervical flexors, there were no significant differences between the different muscles. The higher fat content in the dorsal muscles can be explained by a discrepancy in function between the spine extensors and flexors, reflected in a different muscle fiber distribution. The rather small differences between superficial and deep neck muscles are in line with recent findings that have demonstrated that both muscles groups exhibit phasic activity during isometric muscles contractions and the presumption that there is no difference in fiber type distribution between superficial and deep neck muscles.

Physical inactivity differentially alters dietary oleate and palmitate trafficking

OBJECTIVE

Obesity and diabetes are characterized by the incapacity to use fat as fuel. We hypothesized that this reduced fat oxidation is secondary to a sedentary lifestyle.

RESEARCH DESIGN AND METHODS

We investigated the effect of a 2-month bed rest on the dietary oleate and palmitate trafficking in lean women (control group, n = 8) and the effect of concomitant resistance/aerobic exercise training as a countermeasure (exercise group, n = 8). Trafficking of stable isotope-labeled dietary fats was combined with muscle gene expression and magnetic resonance imaging-derived muscle fat content analyses.

RESULTS

In the control group, bed rest increased the cumulative [1-(13)C]oleate and [d(31)]palmitate appearance in triglycerides (37%, P = 0.009, and 34%, P = 0.016, respectively) and nonesterified fatty acids (NEFAs) (37%, P = 0.038, and 38%, P = 0.002) and decreased muscle lipoprotein lipase (P = 0.043) and fatty acid translocase CD36 (P = 0.043) mRNA expressions. Plasma NEFA-to-triglyceride ratios for [1-(13)C]oleate and [d(31)]palmitate remained unchanged, suggesting that the same proportion of tracers enters the peripheral tissues after bed rest. Bed rest did not affect [1-(13)C]oleate oxidation but decreased [d(31)]palmitate oxidation by -8.2 +/- 4.9% (P < 0.0001). Despite a decreased spontaneous energy intake and a reduction of 1.9 +/- 0.3 kg (P = 0.001) in fat mass, exercise training did not mitigate these alterations but partially maintained fat-free mass, insulin sensitivity, and total lipid oxidation in fasting and fed states. In both groups, muscle fat content increased by 2.7% after bed rest and negatively correlated with the reduction in [d(31)]palmitate oxidation (r(2) = 0.48, P = 0.003).

CONCLUSIONS

While saturated and monounsaturated fats have similar plasma trafficking and clearance, physical inactivity affects the partitioning of saturated fats toward storage, likely leading to an accumulation of palmitate in muscle fat.

The reliability of paraspinal muscles composition measurements using routine spine MRI and their association with back function

This study examines the reliability of quantitative and qualitative muscle composition measurements of paraspinal muscle cross-sectional areas (CSAs) from routine lumbar spine magnetic resonance images and their association with maximal isokinetic lifting performance. The extent of paraspinal muscle composition reflects back function is currently not known. Measurements were repeated 4-8 weeks apart and different measurements of related constructs were compared. Participants were a population-based sample of 169 males, 35-67 years old, without considering the presence or absence of a history of low back pain or related problems in the selection of subjects. The quantitative and qualitative muscle composition measurements for axial magnetic resonance (MR) images of paraspinal muscles at the L3-L4 lumbar spine level, isokinetic lifting force and work, and body fat percentage were the main outcome measures. Results showed that the reproducibility of different paraspinal muscle composition measurements at the L3-L4 level was excellent for CSAs (ICC=0.95-0.99) and quantitative muscle composition measurements using cerebrospinal fluid adjusted signal intensity (ICC=0.96-0.99), and moderate for qualitative muscle composition ratings (Kappa=0.54-0.76). The correlations of the quantitative and qualitative muscle composition measurements with isokinetic lifting force and work were generally low (r=0.02-0.41), and favoured the qualitative assessments. In conclusion, quantitative and qualitative muscle composition measurements of paraspinal muscles are highly reproducible tissue measures, have low associations with body fat and isokinetic lifting performance, and show that paraspinal muscle morphology using routine spine magnetic resonance imaging (MRI) is poorly related to back function.

Postpartum characteristics of rectus abdominis on ultrasound imaging

This cross-sectional and partial longitudinal study aimed to characterize changes in rectus abdominis (RA) and provide reference ranges for the first year postpartum. Ultrasound scanning was used at four stages postnatally to measure cross-sectional area (CSA), thickness, width (indirectly using a shape value) and inter-recti distance (IRD). One hundred and fifteen postnatal women (though some postnatal subjects appeared in more than one postnatal group thus giving a total of 183 data points) and 69 age-matched nulliparous female controls were recruited. Postnatal subjects were studied at Day 1 (PN1; n=63) and at 2 (PN2; n=55), 6 (PN3; n=39) and 12 (PN4; n=26) months postpartum. Longitudinal data were analysed for CSA, thickness, shape (indirect width measurement) (df=67) and IRD (df=62). The mean CSA of the PN1 group was significantly larger (P<0.001) than in controls and decreased (P<0.0021) by 12 months. In all postnatal groups, RA was significantly thinner (P<0.0001, PN1-PN3; P<0.0478, PN4), wider (P<0.0001, PN1-PN3; P=0.0326, PN4) and the IRD was significantly larger (P<0.0001, PN1-PN4) than in controls. Over 2 months postpartum, RA became thicker (P=0.0003) and the width and IRD decreased (P<0.0001 and P=0.0002, respectively) but did not return to control values by 12 months. These results have implications for strength of RA postpartum and anterior abdominal wall stiffness, which together with other muscle characteristics could inform development of effective postnatal exercise programmes.

Association of cross-sectional area of the rectus capitis posterior minor muscle with active trigger points in chronic tension-type headache: a pilot study

OBJECTIVE

To investigate whether cross-sectional area (CSA) of the suboccipital muscles was associated with active trigger points (TrPs) in chronic tension-type headache (CTTH).

DESIGN

Magnetic resonance imaging (MRI) of the cervical spine was performed in 11 females with CTTH aged from 26 to 50 yrs old. CSA for both rectus capitis posterior minor (RCPmin) and rectus capitis posterior major (RCPmaj) muscles were measured from axial T1-weighted images, using axial MRI slices aligned parallel to the C2/3 intervertebral disc. A headache diary was kept for 4 wks to record the pain history. TrPs in the suboccipital muscle were identified by eliciting referred pain to palpation, and increased referred pain with muscle contraction. TrPs were considered active if the elicited referred pain reproduced the head pain pattern and features of the pattern seen during spontaneous headache attacks.

RESULTS

Active TrPs were found in six patients (55%), whereas the remaining five patients showed latent TrPs. CSA of the RCPmin was significantly smaller (F = 13.843; P = 0.002) in the patients with active TrPs (right side: 55.9 +/- 4.4 mm; left side: 61.1 +/-: 3.8 mm) than in patients with latent TrPs (right side: 96.9 +/- 14.4 mm; left side: 88.7 +/- 9.7 mm). No significant differences were found for CSA of the RCPmaj between the patients with either active or latent TrP (P > 0.5).

CONCLUSIONS

It seems that muscle atrophy in the RCPmin, but not in the RCPmaj, was associated with suboccipital active TrPs in CTTH, although studies with larger sample sizes are now required. It may be that nociceptive inputs in active TrPs could lead to muscle atrophy of the involved muscles. Muscle disuse or avoidance behavior can also be involved in atrophy.

Fatty infiltrate in the cervical extensor muscles is not a feature of chronic, insidious-onset neck pain

AIM

To investigate the presence of fatty infiltrate in the cervical extensor musculature in patients with insidious-onset neck pain to better understand the possible pathophysiology underlying such changes in chronic whiplash-associated disorders (WAD).

MATERIALS AND METHODS

A sample of convenience of 23 women with persistent insidious-onset neck pain (mean age 29.2+/-6.9 years) was recruited for the study. Magnetic resonance imaging (MRI) was used to quantify fatty infiltration in the cervical extensor musculature. Quantitative Sensory Testing (QST; pressure and thermal pain thresholds) was performed as sensory features are present in chronic whiplash. Self-reported pain and disability, as well as psychological distress, were measured using the Neck Disability Index (NDI) and the General Health Questionnaire-28 (GHQ-28), respectively.

RESULTS

Measures were compared with those of a previous dataset of chronic whiplash patients (n=79, mean age 29.7+/-7.8 years). Using a classification tree, insidious-onset neck pain was clearly identified from whiplash (p<0.001), based on the presence of MRI fatty infiltrate in the cervical extensor musculature (0/102 individuals) and altered temperature thresholds (cold; 3/102 individuals).

CONCLUSION

Fatty infiltrates in the cervical extensor musculature and widespread hyperalgesia were not features of the insidious-onset neck pain group in this study; whereas these features have been identified in patients with chronic WAD. This novel finding may enable a better understanding of the underlying pathophysiological processes in patients with chronic whiplash.

Rehabilitative ultrasound imaging: understanding the technology and its applications

The use of ultrasound imaging by physical therapists is growing in popularity. This commentary has 2 aims. The first is to introduce the concept of rehabilitative ultrasound imaging (RUSI), provide a definition of the scope of this emerging tool in regard to the physical therapy profession, and describe how this relates to the larger field of medical ultrasound imaging. The second aim is to provide an overview of basic ultrasound imaging and instrumentation principles, including an understanding of the various modes and applications of the technology with respect to neuromusculoskeletal rehabilitation and in relation to other common imaging modalities.

Magnetic resonance imaging study of the morphometry of cervical extensor muscles in chronic tension-type headache

This study analyses the differences in the relative cross-sectional area (rCSA) of several cervical extensor muscles, assessed by magnetic resonance imaging (MRI), between patients with chronic tension-type headache (CTTH) and healthy controls. MRI of the cervical spine was performed on 15 CTTH females and 15 matched controls. The rCSA values for the rectus capitis posterior minor (RCPmin), rectus capitis posterior major (RCPmaj), semispinalis capitis and splenius capitis muscles were measured from axial T1-weighted images using axial MR slices aligned parallel to the C2/3 intervertebral disc. A headache diary was kept for 4 weeks in order to substantiate the diagnosis and record the pain history. CTTH patients showed reduced rCSA for both RCPmin and RCPmaj muscles (P < 0.01), but not for semispinalis and splenius capitis muscles, compared with controls. Headache intensity, duration or frequency and rCSA in both RCPmin and RCPmaj muscles were negatively correlated (P < 0.05): the greater the headache intensity, duration or frequency, the smaller the rCSA in the RCPmin and RCPmaj muscles. CTTH patients demonstrate muscle atrophy of the rectus capitis posterior muscles. Whether this selective muscle atrophy is a primary or secondary phenomenon remains unclear. In any case, muscle atrophy could possibly account for a reduction of proprioceptive output from these muscles, and thus contribute to the perpetuation of pain.

Fatty infiltration in the cervical extensor muscles in persistent whiplash-associated disorders: a magnetic resonance imaging analysis

STUDY DESIGN

Cross-sectional investigation of muscle changes in patients suffering from persistent whiplash-associated disorders (WAD).

OBJECTIVES

To quantitatively compare the presence of fatty infiltrate in the cervical extensor musculature in a cohort of chronic whiplash patients (WAD II) and healthy control subjects across muscle and cervical segmental level.

SUMMARY OF BACKGROUND DATA

Magnetic resonance imaging (MRI) can be regarded as the gold standard for muscle imaging; however, there is little knowledge about in vivo features of neck extensor muscles in patients suffering from persistent WAD and how fat content alters across the factors of muscle, vertebral segments, age, self-reported pain and disability, compensation status, body mass index, and duration of symptoms.

METHODS

A reliable MRI measure for fatty infiltrate was performed of the cervical extensor muscles bilaterally in 113 female subjects (79 WAD, 34 healthy control; 18-45 years, 3 months to 3 years post injury). The measure was performed on all subjects for the rectus capitis posterior minor and major, multifidus, semispinalis cervicis and capitis, splenius capitis, and upper trapezius.

RESULTS

The WAD subjects had significantly larger amounts of fatty infiltrate for all of the cervical extensor muscles compared with healthy control subjects (all P < 0.0001). In addition, the amount of fatty infiltrate varied by both cervical level and muscle, with the rectus capitis minor/major and multifidi at C3 having the largest amount of fatty infiltrate (P < 0.0001). Intramuscular fat was independent of age, self-reported pain/disability, compensation status, body mass index, and duration of symptoms.

CONCLUSION

There is significantly greater fatty infiltration in the neck extensor muscles, especially in the deeper muscles in the upper cervical spine, in subjects with persistent WAD when compared with healthy controls. Future studies are required to investigate the relationships between muscular alterations and symptoms in patients suffering from persistent WAD.