Whole spine localizers of magnetic resonance imaging detect unexpected vertebral fractures.

BACKGROUND: Whole spine localizers (WS-loc) of magnetic resonance imaging (MRI) are performed for enumeration of the vertebrae but they can be also used for the evaluation of the spine. PURPOSE: To assess the accuracy of fracture detection using WS-locs of MRI and compare the findings with standard high-resolution short tau inversion recovery (STIR) sequences, and to determine whether the review of WS-locs is useful and if additional information can be gained by assessing the thoracic spine section of the WS-locs. MATERIAL AND METHODS: A total of 298 magnetic resonance (MR) examinations of the lumbar spine with WS-locs were evaluated. Two independent readers reviewed the images. In case of fracture detection, further characterization of the fracture was performed. To assess inter-reader agreement, unweighted Cohen's kappa with 95% confidence intervals (CI) and Phi coefficients were calculated. RESULTS: The study sample included 187 female and 111 male patients (age range = 65-94 years; median age = 75.0 years). The WS-locs detected 42 fractures of the lumbar spine and 36 of the thoracic spine. Inter-reader agreement for fracture detection in the lumbar and thoracic spine was strong (K = 0.87, 95% CI = 0.78-0.95, Phi = 0.87, and K = 0.88, 95% CI = 0.79-0.96, Phi = 0.88, respectively). CONCLUSION: WS-locs from MR examinations of the lumbar spine provide a good diagnostic tool for the detection and evaluation of unsuspected vertebral fractures. WS-locs show strong inter-reader agreement for fracture detection in the thoracic and lumbar spine.

Anatomy-based MRI assessment of the iliopsoas muscle complex after pertrochanteric femoral fracture.

OBJECTIVE: To evaluate the quality of the iliopsoas muscle complex after pertrochanteric femoral fracture, using MRI; to propose an anatomy-based evaluation of the iliopsoas muscle complex; and to determine the inter-reader reliability of two classifications of fatty muscle degeneration. MATERIALS AND METHODS: We included adult patients with a displaced lesser trochanter following pertrochanteric femoral fracture. Muscle quality was evaluated using the Goutallier and Slabaugh classifications at three levels (L4/L5, L5/S1, and the anterior inferior iliac spine). Two radiologists independently reviewed the MRIs, and force measurement was performed on both hips. Linear mixed-effects models were used to determine the effect of fracture on muscle quality and strength, and Cohen's kappa statistic was used to assess inter-reader agreement. RESULTS: In the 18 patients included, the iliopsoas muscle complex showed higher grades of fatty muscle degeneration on the fractured side than on the non-fractured side. The mean difference between muscle strength on the fractured vs the non-fractured side was -12 N (p > 0.05). Inter-reader agreement for the Goutallier and Slabaugh classifications was good and very good respectively (weighted K = 0.78 and 0.85 respectively). CONCLUSION: Fatty muscle degeneration of the iliopsoas muscle complex after pertrochanteric femoral fracture was evident using both classification systems; however, fatty muscle degeneration resulted in only a minimal reduction of muscle strength. To provide a thorough assessment of iliopsoas muscle complex quality, we suggest evaluating it at different anatomical levels. Regarding inter-reader agreement, the Slabaugh classification was superior to the Goutallier classification.

Lipidus migrans-a radiology imaging feature after ankle injury.

We present an uncommon imaging feature with fluid fat tracking within the tendon sheath of the flexor hallucis longus (FHL) after traumatic injury to the ankle joint. We propose a coined medical term "lipidus migrans" to define the presence of floating fat in a tendon sheath. This is due to lipohemarthrosis from intra-articular fracture of the ankle with leakage of fluid fat into the tendon sheath. Communication between the FHL tendon sheath and ankle joint can occur in up to 25% of patients. Radiologists should be aware of the presence of lipidus migrans as a potential posttraumatic complication after intra-articular ankle fracture and that fat in the tendon sheath may mimic fracture fragments or even a tendon sheath tumor.

Normative MR cervical spinal canal dimensions.

PURPOSE: To provide normal values of the cervical spinal canal and spinal cord dimensions in several planes with respect to spinal level, age, sex, and body height. MATERIALS AND METHODS: This study was approved by the institutional review board; all individuals provided signed informed consent. In a prospective multicenter study, two blinded raters independently examined cervical spine magnetic resonance (MR) images of 140 healthy volunteers who were white. The midsagittal diameters and areas of spinal canal and spinal cord, respectively, were measured at the midvertebral levels of C1, C3, and C6. A multivariate general linear model described the influence of sex, body height, age, and spinal level on the measured values. RESULTS: There were differences for sex, spinal level, interaction between sex and level, and body height, while age had significant yet limited influence. Normative ranges for the sagittal diameters and areas of spinal canal and spinal cord were defined at C1, C3, and C6 levels for men and women. In addition to a calculation of normative ranges for a specific sex, spinal level, age, and body height data, data for three different height subgroups at 45 years of age were extracted. These results show a range of the spinal canal dimensions at C1 (from 10.7 to 19.7 mm), C3 (from 9.4 to 17.2 mm), and C6 (from 9.2 to 16.8 mm) levels. CONCLUSION: The dimensions of the cervical spinal canal and cord in healthy individuals are associated with spinal level, sex, age, and height. Online supplemental material is available for this article.

Does normalized signal intensity of cervical discs on T2 weighted MRI images change in whiplash patients?

PURPOSE: We tested the hypothesis that whiplash trauma leads to changes of the signal intensity of cervical discs in T2-weighted images. METHODS AND MATERIALS: 50 whiplash patients (18-65 years) were examined within 48h after motor vehicle accident, and again after 3 and 6 months and compared to 50 age- and sex-matched controls. Signal intensity in ROI's of the discs at the levels C2/3 to C7/T1 and the adjacent vertebral bodies were measured on sagittal T2 weighted MR images and normalized using the average of ROI's in fat tissue. The contrast between discs and both adjacent vertebrae was calculated and disc degeneration was graded by the Pfirrmann-grading system. RESULTS: Whiplash trauma did not have a significant effect on the normalized signals from discs and vertebrae, on the contrast between discs and adjacent vertebrae, or on the Pfirrmann grading. However, the contrast between discs and adjacent vertebrae and the Pfirrmann grading showed a strong correlation. In healthy volunteers, the contrast between discs and adjacent vertebrae and Pfirrmann grading increased with age and was dependent on the disc level. CONCLUSION: We could not find any trauma related changes of cervical disc signal intensities. Normalized signals of discs and Pfirrmann grading changed with age and varied between disc levels with the used MR sequence.

Retroperitoneal sarcomas: a review of disease spectrum, radiological features, characterisation and management.

Retroperitoneal sarcomas are a rare disease. The overall 5-year survival rate for these lesions remains low, and surgical management offers the only option for effective treatment and potential for cure. Radiotherapy is increasingly being employed in addition to standard surgical treatment. Improvements in cross-sectional imaging have also facilitated better characterisation of lesions, preoperative planning and long-term follow-up. This article reviews the current literature and documents the various types of retroperitoneal sarcomas with a particular approach to their imaging features. We also highlight the pathology, diagnostic methods and most current management of these tumours.

Femoroacetabular impingement.

Femoroacetabular impingement (FAI) of the hip is a well-recognized entity that can cause hip pain and limit range of motion. Although there are 2 types of FAI (cam and pincer), these 2 entities most commonly coexist. Plain radiographs and magnetic resonance imaging are commonly used to assess FAI, and play an integral role in diagnosis in conjunction with patient symptoms and clinical examination. Treatment of FAI is also evolving, with arthroscopic management becoming increasingly more popular. This review provides an overview of the proposed etiology, mechanisms, clinical history, imaging, and treatment of FAI.

MRI "row of dots sign" in gossypiboma: an enlarging mass 8 months after sarcoma resection.

The retention of foreign bodies after surgery is rare, but carries significant morbidity and mortality as well as financial and legal implications. Such retained items cause a foreign-body reaction, which in the case of cotton-based materials are called gossypibomas. We present the case of an 84-year-old woman with a pseudotumor secondary to a retained dressing gauze roll, presenting 5 months after resection of a gluteal sarcoma, which had raised concerns of local recurrence. We also outline the imaging modalities that may assist in diagnosis of a retained foreign body, and suggest the MRI "row of dots" sign as a useful radiological feature associated with gossypiboma. Awareness of the imaging appearances of retained foreign bodies allows the inclusion of this possibility in differential diagnosis of a mass in patients with a surgical history.

Femoroacetabular impingement.

Femoroacetabular impingement (FAI) is a common cause of early-onset osteoarthritis of the hip. It can be caused by morphologic abnormalities involving the proximal femur or acetabulum, leading to abnormal abutment of the femoral head-neck against the acetabular rim. This repetitive trauma causes mechanical wear of the labrum and articular cartilage, leading to osteoarthritis of the hip. Magnetic resonance imaging is an accurate noninvasive imaging modality that can detect acetabular labral lesions and adjacent cartilage damage, and is able to detect underlying subtle anatomic variations of the femoral head-neck junction and acetabulum associated with FAI.

Injuries of the spine sustained whilst surfboard riding.

Surfboard riding is a popular sport worldwide. Although surfing is considered a 'safe' pastime, significant injuries do occur, particularly to the head and cervical spine. Spinal injuries most commonly occur when the surfer's head strikes the seafloor. This case series identifies the spectrum of spinal pathologies sustained whilst surfing and their imaging appearances. No similar study has previously been published.

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.

Meniscal tear - presentation, diagnosis and management.

BACKGROUND: Medial and lateral knee joint menisci serve to transfer load and absorb shock, aid joint stability and provide lubrication. The meniscus is the most commonly injured structure in the knee joint. Imaging techniques such as magnetic resonance imaging may be warranted but are no substitute for thorough clinical history and examination. OBJECTIVE: This article outlines the aetiology, presentation, diagnosis (both clinical and radiographic) and management of these important injuries. DISCUSSION: Magnetic resonance imaging can confirm clinical concern for meniscal tear, review intra- and extra-articular anatomical structures and exclude alternative diagnoses. Meniscal tears can be assessed arthroscopically for stability and vascularity. Even partial meniscectomy may lead to osteoarthritis. On the basis of the findings, treatment can be considered in terms of four Rs: Rest and Rehabilitate the patient (with physiotherapy), and if the patient is not improving on Review, Refer to an orthopaedic surgeon. New experimental surgical techniques seek to replace damaged tissue. These include meniscal allograft transplantation, biosynthetic scaffolds, growth factor and gene therapy, or a combination of these.

Femoroacetabular impingement.

Femoroacetabular impingement (FAI) is a pathomechanical concept describing the early and painful contact of morphological changes of the hip joint, both on the acetabular, and femoral head sides. These can lead clinically to symptoms of hip and groin pain, and a limited range of motion with labral, chondral and bony lesions. Pincer impingement generally involves the acetabular side of the joint where there is excessive coverage of the acetabulum, which may be focal or more diffuse. There is linear contact of the acetabulum with the head/neck junction. Cam impingement involves the femoral head side of the joint where the head is associated with bony excrescences and is aspheric. The aspheric femoral head jams into the acetabulum. Imaging appearances are reviewed below. This type is evident in young males in the second and third decades. The main features of FAI are described.

Are there cervical spine findings at MR imaging that are specific to acute symptomatic whiplash injury? A prospective controlled study with four experienced blinded readers.

PURPOSE: To compare the magnetic resonance (MR) imaging findings in patients with acute whiplash injury with those in matched control subjects. MATERIALS AND METHODS: In a prospective multicenter controlled study, from 2005 to 2008, 100 consecutive patients underwent 1.5-T MR imaging examinations of the cervical spine within 48 hours after a motor vehicle accident. Findings in these patients were compared in a blinded fashion with those in 100 age- and sex-matched healthy control subjects. Four blinded independent readers assessed the presence of occult vertebral body and facet fractures, vertebral body and facet contusions, intervertebral disk herniations, ligamentum nuchae strains, ligamentum nuchae tears, muscle strains or tears, and perimuscular fluid. Accuracy (as compared with clinical findings) and interobserver reliability were calculated. RESULTS: Accuracy of MR imaging and interreader reliability were generally poor (sensitivity, 0.328; specificity, 0.728; positive and negative likelihood ratios, 1.283 and 1.084, respectively). MR imaging findings significantly associated with whiplash injuries were occult fracture (P<.01), bone marrow contusion of the vertebral body (P=.01), muscle strain (P<.01) or tear (P<.01), and the presence of perimuscular fluid (P<.01). While 10 findings thought to be specific for whiplash trauma were significantly (P<.01) more frequent in patients (507 observations), they were also regularly found in healthy control subjects (237 observations). There were no serious occult injuries that required immediate therapy. CONCLUSION: MR imaging at 1.5 T reveals only limited evidence of specific changes to the cervical spine and the surrounding tissues in patients with acute symptomatic whiplash injury compared with healthy control subjects.

Pearls and pitfalls of magnetic resonance imaging of the upper extremity.

Magnetic resonance imaging (MRI) is capable of producing images in any anatomical plane, visualizing and analyzing a variety of tissue characteristics, as well as quantifying blood flow and metabolic functions. Although MRI details of compact bone and calcium are poor when compared to those taken with plain radiography or computed tomography, its high soft tissue contrast discrimination and multiplanar imaging capabilities are significant advantages. Musculoskeletal anatomy and neurovascular bundles are well delineated. The advent of MRI has revolutionized the clinician's ability to confirm a proper diagnosis for musculoskeletal problems, which has led to more directed, specific rehabilitative protocols. However, the value of MRI to rehabilitative professionals has been even greater in its ability to identify serious, more uncommon pathologies, such as in those with underlying infection, fracture, or tumor, that require immediate care and are considered to be beyond their scope of practice. Furthermore, MRI, with its precise delineation of fat, muscle, and bone, is an ideal candidate for imaging of muscle disease or injury and has emerged as the method of choice for the detection of early cartilage wear in young patients, such as osteoarthritis. Finally, this imaging modality can avoid radiation exposure in a predominantly younger patient cohort commonly affected by musculoskeletal diseases. The aim of this paper is to consider how physical therapists may take advantage of the diagnostic value of MRI of the upper limb, while avoiding the pitfalls of misinterpretation of images as a result of technical issues, pathological changes, or normal variants.

Alterations of the transverse ligament: an MRI study comparing patients with acute whiplash and matched control subjects.

OBJECTIVE: The objective of our study was to evaluate whether there is injury to the transverse ligament of the atlas in patients with acute whiplash. MATERIALS AND METHODS: Ninety patients with an acute (< 48 hours) symptomatic whiplash-associated injury and 90 healthy age- and sex-matched asymptomatic control subjects (mean age of patients and control subjects, 36 years) were included. The maximal sagittal thickness of the transverse ligament was measured on midsagittal T1 volumetric interpolated breath-hold examination (VIBE) images and transverse reformatted VIBE images. The signal intensity of the transverse ligament was measured on transverse STIR images and on transverse reformatted T1 VIBE images before and after IV administration of gadoterate. Contrast between the transverse ligament and CSF and alterations of contrast after gadoterate injection were calculated. RESULTS: Patients had a minimally thicker transverse ligament (posttraumatic swelling) than control subjects, and the difference in thickness was significant in men only (p = 0.03). In patients, a significant signal alteration of the transverse ligament (p = 0.03) was seen on STIR (posttraumatic edema) and native VIBE sequences. The contrast between the transverse ligament and the CSF on VIBE images was significantly (p = 0.005) lower in patients than in control subjects. With the application of a contrast agent, the contrast difference between the transverse ligament and CSF in patients and control subjects was less pronounced (p = 0.038). There was no abnormal uptake of contrast agent by the transverse ligament or CSF. CONCLUSION: The results of our study indicate possible involvement of the transverse ligament in whiplash injury. Although MRI may be helpful to study injury-related changes of anatomic structures in cohorts, it is not suited for individual diagnosis because the alterations are too small.

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.

Magnetic resonance imaging in traumatic posterior hip dislocation.

OBJECTIVES: The objective was to report the ability of a magnetic resonance image to document the integrity of the obturator externus tendon after posterior hip dislocation as a potential predictor for preserved femoral head vascularity. DESIGN: Retrospective radiographic and clinical pilot study. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: Nineteen consecutive patients with traumatic posterior hip dislocation. OUTCOME EVALUATION: Intraoperative correlation of soft tissue damage and radiographic assessment of avascular necrosis of the femoral head 3 years postinjury. METHODS: Magnetic resonance imaging performed in the acute phase of posterior hip dislocation. Correlation with intraoperative findings during surgical hip dislocation and with avascular necrosis 3 years postinjury. RESULTS: The obturator externus tendon was intact in all cases with preserved femoral head vascularity. After a 3-year follow up, there were no cases of avascular necrosis. CONCLUSION: In this small series of patients, posterior hip dislocation did not imply a tear of the obturator externus muscle. An intact obturator externus tendon suggests preservation of the deep branch of the medial femoral circumflex artery to the femoral head.