Search

A 23-year-old man with schwannomatosis1 was imaged with whole-body MRI and 18F FDG-PET to assess the extent of disease prior to initiating systemic therapy for new and growing tumors. The patient had undergone multiple prior resections of schwannomas from peripheral nerves. …

Tendon tissue engineering with a biomaterial scaffold that mimics the tendon extracellular matrix (ECM) and is biomechanically suitable, and when combined with readily available autologous cells, may provide successful regeneration of defects in tendon. Current repair strategies using suitable autografts and freeze-dried allografts lead to a slow repair process that is sub-optimal and fails to restore function, particularly in difficult clinical situations such as zone II flexor tendon injuries of the hand. We have investigated the effect of GDF-5 on cell proliferation and gene expression by primary rat adipose-derived stem cells (ADSCs) that were cultured on a poly(DL-lactide-co-glycolide) PLAGA fiber scaffold and compared to a PLAGA 2D film scaffold. The electrospun scaffold mimics the collagen fiber bundles present in native tendon tissue, and supports the adhesion and proliferation of multipotent ADSCs. Gene expression of scleraxis, the neotendon marker, was upregulated seven- to eightfold at 1 week with GDF-5 treatment when cultured on a 3D electrospun scaffold, and was significantly higher at 2 weeks compared to 2D films with or without GDF-5 treatment. Expression of the genes that encode the major tendon ECM protein, collagen type I, was increased by fourfold starting at 1 week on treatment with 100 ng mL(-1) GDF-5, and at all time points the expression was significantly higher compared to 2D films irrespective of GDF-5 treatment. Thus stimulation with GDF-5 can modulate primary ADSCs on a PLAGA fiber scaffold to produce a soft, collagenous musculoskeletal tissue that fulfills the need for tendon regeneration.

The radial nerve is a continuation of the posterior cord of the brachial plexus and one of the major nerves that provide motor and sensory innervations to the forearm. MR imaging evaluation of the radial nerve pathology has been described in scattered case reports. Current high-field MR scanners enable high resolution and high contrast imaging of the peripheral nerves. This article reviews the 3 Tesla magnetic resonance neurography imaging of radial nerve anatomy and various pathologies affecting it with relevant case examples.

OBJECTIVE. The ever-increasing use of higher field strength (3 T) scanners and novel pulse sequences with improved spatial resolution and signal-to-noise ratio have rendered MR neurography (MRN) a valuable technique in the assessment of peripheral neuropathies. The aim of this study is to illustrate the imaging findings of high-resolution MRN in patients who suffer from tibial nerve entrapment due to a soleal fibromuscular sling and to correlate the imaging findings with intraoperative and clinical examination results.CONCLUSION. This article depicts the surgically confirmed imaging findings of high-resolution MRN in tibial nerve entrapment by the soleal sling.

Rationale and Objectives The purpose of this study was to illustrate the imaging findings on high-resolution 3T magnetic resonance neurography (MRN) in patients with suprascapular nerve (SSN) neuropathy. Materials and Methods From 3T MRN examinations performed for brachial plexus evaluation in 51 patients over a 3-year period, 15 patients with final diagnosis of suprascapular neuropathy were recruited. The diagnosis was confirmed by electrodiagnostic studies (EDS), clinical, and/or surgical follow-up examinations. Studies performed for the evaluation of tumor, neurofibromatosis, or known diffuse polyneuropathy were excluded. Results Two cases were excluded due to suboptimal imaging related to motion degradation and poor signal-to-noise ratio. MRN depicted asymmetric enlargement and/or abnormal T2 hyperintensity of C5 nerve root (10/13 cases), C6 nerve root (10/13 cases), both C5 and C6 nerve roots (7/13 cases), upper trunk (11/13 cases) and SSN (11/13 cases), and other brachial plexus segments involvement (4/13 cases). MR findings of denervation changes in the ipsilateral supraspinatus and infraspinatus muscles were detected in 12/13 cases. In all seven cases where contrast-enhanced images were available, MRN demonstrated enhancement of the denervated muscles but did not provide any additional information regarding the nerve abnormality. None of the MRN studies revealed a mass lesion along the course of the SSN. Conclusion 3T MRN is a valuable diagnostic tool in clinically suspected cases of suprascapular neuropathy, because it can directly demonstrate the nerve abnormality, as well as secondary muscle denervation changes. The reader should be aware that brachial plexopathy may coexist in patients with clinical diagnosis of SSN neuropathy.

MRI has been used for almost two decades for the evaluation of peripheral nerve disorders. This article highlights the relative advantages and disadvantages of 3T MR neurography in the evaluation of peripheral neuropathies. The authors also describe the high-resolution MR neurography technique on 3T MRI, along with the approach to its interpretation that has evolved at one institution.

Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment.

Advances in orthopedic and arthroscopic surgical procedures of the knee such as, knee replacement, ligamentous reconstruction as well as articular cartilage and meniscus repair techniques have resulted in a significant increase in the number of patients undergoing knee arthroscopy or open surgery. As a consequence postoperative MR imaging examinations increase. Comprehensive knowledge of the normal postoperative MR imaging appearances and abnormal findings in the knee associated with failure or complications of common orthopedic and arthroscopic surgical procedures currently undertaken is crucial. This article reviews the various normal and pathological postoperative MR imaging findings following anterior and posterior cruciate ligament, medial collateral ligament and posterolateral corner reconstruction, meniscus and articular cartilage surgery as well as total knee arthroplasty with emphasis on those surgical procedures which general radiologists will likely be faced in their daily clinical routine. J. Magn. Reson. Imaging 2011;. © 2011 Wiley-Liss, Inc.

The common peroneal nerve (CPN), a major terminal branch of the sciatic nerve, can be subject to a variety of pathologies, which may affect the nerve at any level from the lumbar plexus to its distal branches. Although the diagnosis of peripheral neuropathy is traditionally based on a patient's clinical findings and electrodiagnostic tests, magnetic resonance neurography (MRN) is gaining an increasing role in the definition of the type, site, and extent of peripheral nerve disorders. Current high-field MR scanners enable high-resolution and excellent soft-tissue contrast imaging of peripheral nerves. In the lower extremities, MR neurography has been employed in the demonstration of the anatomy and pathology of the CPN, as well as in the detection of associated secondary muscle denervation changes. This article reviews the normal appearance of the CPN as well as typical pathologies and abnormal findings at 3.0-T MR neurography of the lower extremity.

The posterior tibial tendon (PTT) is the most important dynamic stabilizer of the medial ankle and longitudinal arch of the foot. PTT dysfunction is a degenerative disorder of the tendon, which secondarily involves multiple ligaments, joint capsules, fascia, articulations, and bony structures of the ankle, hindfoot, midfoot, and forefoot. When the tendon progressively attenuates, the patient develops a painful, progressive collapsed flatfoot or pes planovalgus deformity. This comprehensive review illustrates the 3-Tesla magnetic resonance imaging (3T MRI) features of PTT dysfunction. In addition, the reader will gain knowledge of the expected pathologic findings on MRI, as they are related to clinical staging of PTT dysfunction.

MR imaging of peripheral nerves has been described in relation to abnormalities such as nerve injury, entrapment, and neoplasm. Neuroma formation is a known response to peripheral nerve injury, and here we correlate the MRN appearance of postinjury neuroma formation with intraoperative findings. We also present the MR imaging features of surgical treatment with a synthetic nerve tube and nerve wrap on postoperative follow-up imaging.

MR-guided HIFU is an effective treatment for metastatic bone pain through periosteal nerve ablation,[1] and is being investigated for treating back pain through facet joint denervation.[2] For peripheral neuropathy, ultrasound-guided HIFU has been investigated preclinically as a means of achieving either an irreversible conduction block to treat severe spasticity,[3] or a reversible partial conduction block to alleviate chronic pain.[4] However, ultrasound offers limited visualization of deeply situated pelvic nerves [5] and lacks the ability to measure thermal dose, which predicts the extent of changes in peripheral nerve histology and function.[6] Recently developed diffusion-prepared 3D MR neurography imaging techniques with fat suppression and nerve-selective T2-weighting [7] could improve targeting accuracy over ultrasound guidance. We present initial investigations into the use of MRI to guide HIFU ablation of peripheral nerves in a swine model. The objectives were 1) to evaluate the feasibility of identifying peripheral nerves using MR neurography on the clinical MR-HIFU system, 2) to monitor HIFU ablation of peripheral nerves using MR thermometry, and 3) to evaluate the ability to measure thermal lesions in peripheral nerves using contrast-enhanced T1-weighted images and thermal dose maps calculated from MR thermometry.

Summary: Primary sphenoid melanoma is a rare tumor. A 75-year-old man presented with complaints of headache and visual complaints for a few days. CT and MRI of the brain demonstrated a sphenoid sinus mass with appearances suggesting a diagnosis of melanoma. Fine-needle aspiration biopsy confirmed the diagnosis. Other differential diagnostic considerations on CT and MRI are discussed. We also discuss the further role of contrast MRI in determining the actual extent of the tumor in the critical skull base area.

Desmoplastic fibroma of bone is a rare benign primary bone tumor that is thought to be the intraosseous counterpart of the soft tissue desmoid tumors. It may involve almost any bone in the skeletal system, most frequently affecting the metaphysis of long bones and the mandible. Though the tumor is benign, it has a propensity towards local infiltration [1]. Clinically, the commonest presentation is pain, palpable mass, and swelling; although it may be discovered as incidental finding on imaging. The lesion may also become evident after a pathological fracture [2]. The majority of cases are reported in patients younger than 30 years of age. In the present case, the patient was a 46-year-old man who underwent imaging of his right knee for anterior patellar pain and was incidentally found to have a lytic-sclerotic lesion in the distal metaphysis of the femur. A radiologist must be vigilant in the recognition of this entity due to its characteristic imaging appearance, otherwise it may be confused with other benign fibrous lesions or more importantly, sarcoma [1]. On radiographs, the matrix appears nonmineralized with coarse ridge-like internal trabeculations (Fig. 1 in the case presentation); it may breach the cortex in a few cases demonstrating a “soap bubble” appearance. The margins appear well defined and sclerotic in most cases. Similar features are seen on computed tomography (Fig. 2 in the case presentation) [3]. Tc99 M bone scan shows uptake in the sclerotic peripheral area of the lesion (Fig. 3 in the case presentation). Magnetic resonance imaging (MRI) is also distinctive in the diagnosis of this lesion. T1W sequence shows isoto hypointense signal intensity to adjacent normal muscles. T2W sequence depicts foci of low or intermediate signal intensity due to presence of dense fibrous matrix and the relative acellularity of the tumor. The more cellular parts of the tumor with fibroblasts or necrotic areas are responsible for the higher signal intensity within the lesion. Heterogeneous contrast enhancement of the tumor is seen with peripheral areas of intense enhancement (Fig. 4 in the case presentation) [3, 4]. Histopathology shows wavy fibroblasts with uniform nuclei (black arrows) inlaying in an extensive collagenous stroma with partly dense collagen bundles (white arrows) (Fig. 5 in the case presentation). The patient was treated with curettage and bone grafting with cementing; however, a high recurrence rate has been reported with this conservative treatment modality [5]. The treatment of choice, therefore, is wide tumor resection. Taconis et al. in their analysis of 18 cases of desmoplastic tumor, found no recurrence occurring after 9-year follow-up in patients treated with wide resection [2].

AIM: To investigate whether congenital lumbar spinal stenosis (CLSS) is associated with a specific degenerative changes of the lumbar spine. METHODS: The lumbar spine magnetic resonance imaging studies of 52 subjects with CLSS and 48 control subjects were retrospectively evaluated. In each examination, the five lumbar levels were assessed for the presence or absence of circumferential or shallow annular bulges, annular tears, anterior or posterior disc herniations, epidural lipomatosis, Schmorl’s nodes, spondylolisthesis, pars defects, and stress reactions of the posterior vertebral elements. RESULTS: Compared to control individuals, subjects with CLSS exhibited increased incidence of circumferential and shallow annular bulges, annular tears, disc herniations and spondylolisthesis (P < 0.05). CONCLUSION: CLSS is associated with increased incidence of degenerative changes in specific osseous and soft-tissue elements of the lumbar spine.

AIM: To evaluate two simple angle measurements for predicting lumbosacral transitional vertebra (LSTV) in magnetic resonance imaging (MRI) studies of the spine. METHODS: The lumbar spine MRI studies of 50 subjects with LSTV and 50 subjects with normal lumbosacral anatomy were retrospectively evaluated. In each study, the mid-sagittal T2-weighted image was used to measure the angle formed by a line parallel to the superior surface of the sacrum and a line perpendicular to the axis of the scan table (A-angle), as well as the angle formed by a line parallel to the superior endplate of the L3 vertebra and a line parallel to the superior surface of the sacrum (B-angle). RESULTS: The total study population consisted of 100 subjects (46 males, 54 females, 51 ± 16 years old). There were no differences in age and sex between the two groups. Both A-angle and B-angle were significantly increased in subjects with LSTV compared to controls (P < 0.05). The optimal cut-off values of A-angle and B-angle for the prediction of LSTV were 39.8° (sensitivity = 80%, specificity = 80%, accuracy = 83%; 95% confidence interval = 74%-89%, P = 0.0001) and 35.9° (sensitivity = 80%, specificity = 54%, accuracy = 69%; 95% confidence interval = 59%-78%, P = 0.0005), respectively. CONCLUSION: On sagittal MR images of the lumbar spine, an increased A-angle and/or B-angle should alert the radiologist to the presence of LSTV.

Background: Magnetic resonance neurography (MRN) has an increasing role in the diagnosis and management of pudendal neuralgia, a neurogenic cause of chronic pelvic pain. Objective: The objective of this research was to determine the role of MRN in predicting improved pain outcomes following computed tomography (CT)-guided perineural injections in patients with pudendal neuralgia. Study Design: This study used a retrospective cross-sectional study design. Setting: The research was conducted at a large academic hospital. Methods: Patients: Ninety-one patients (139 injections) who received MRN and CT-guided pudendal blocks were analyzed. Intervention: A 3Tesla (T) scanner was used to evaluate the lumbosacral plexus for pudendal neuropathy. Prior to receiving a CT-guided pudendal perineural injection, patients were given pain logs and asked to record pain on a visual analog scale. Measurement: MRN findings for pudendal neuropathy were compared to the results of the CTguided pudendal nerve blocks. Injection pain responses were categorized into 3 groups – positive block, possible positive block, and negative block. Statistical Tests: A chi-square test was used to test any association, and a Cochran-Armitage trend test was used to test any trend. Significance level was set at .05. All analyses were done in SAS Version 9.4 (SAS Institute, Inc., Cary, NC). Results: Ninety-one patients (139 injections) who received MRN were analyzed. Of these 139 injections, 41 were considered positive (29.5%), 52 of 139 were possible positives (37.4%), and 46 of 139 were negative blocks (33.1%). Of the patients who had a positive pudendal block, no significant difference was found between the MRN result and the pudendal perineural injection response (P = .57). Women had better overall response to pudendal blocks, but this response was not associated with MRN findings (P = .34). However, positive MRN results were associated with better pain response in men (P = .005). Patients who reported bowel dysfunction also had a better response to pudendal perineural injection (P = .02). Limitations: Some limitations include subjectivity of pain reporting, reporting consistency, absence of a control group, and the retrospective nature of the chart review. Conclusion: Pudendal perineural injections improve pain in patients with pudendal neuralgia and positive MRN results are associated with better response in men. Key words: MRI, MRN, CT injection, pudendal neuralgia, pudendal nerve, pelvic pain, chronic pelvic pain, pudendal neuropathy