Ontology-based image navigation: exploring 3.0-T MR neurography of the brachial plexus using AIM and RadLex.

Disorders of the peripheral nervous system have traditionally been evaluated using clinical history, physical examination, and electrodiagnostic testing. In selected cases, imaging modalities such as magnetic resonance (MR) neurography may help further localize or characterize abnormalities associated with peripheral neuropathies, and the clinical importance of such techniques is increasing. However, MR image interpretation with respect to peripheral nerve anatomy and disease often presents a diagnostic challenge because the relevant knowledge base remains relatively specialized. Using the radiology knowledge resource RadLex®, a series of RadLex queries, the Annotation and Image Markup standard for image annotation, and a Web services-based software architecture, the authors developed an application that allows ontology-assisted image navigation. The application provides an image browsing interface, allowing users to visually inspect the imaging appearance of anatomic structures. By interacting directly with the images, users can access additional structure-related information that is derived from RadLex (eg, muscle innervation, muscle attachment sites). These data also serve as conceptual links to navigate from one portion of the imaging atlas to another. With 3.0-T MR neurography of the brachial plexus as the initial area of interest, the resulting application provides support to radiologists in the image interpretation process by allowing efficient exploration of the MR imaging appearance of relevant nerve segments, muscles, bone structures, vascular landmarks, anatomic spaces, and entrapment sites, and the investigation of neuromuscular relationships.

Spectrum of superficial nerve-related tumor and tumor-like lesions: MRI features.

Superficial soft-tissue masses arising from skin appendages, metastasis, and inflammatory lesions have been widely reported. However, nerve-related superficial mass-like lesions other than peripheral nerve sheath tumors are less commonly described. High resolution magnetic resonance imaging (MRI) is an excellent non-invasive tool for the evaluation of such lesions. In this article, the authors discuss the entire spectrum of these lesions and also outline a systemic diagnostic approach.

Magnetic resonance neurography of common peroneal (fibular) neuropathy.

OBJECTIVE: To examine diagnostic accuracy of semiquantitative and qualitative magnetic resonance neurography criteria in common peroneal nerve (CPN) neuropathy. MATERIALS AND METHODS: Institutional review board approval was obtained with a waiver of informed consent for this Health Insurance Portability and Accountability Act-compliant retrospective study. A review of 28 knees in 28 subjects (12 males and 16 females; age range, 13-84 years; mean [SD] age, 42 [20] years) who had undergone magnetic resonance neurography of the knee was performed. Thirteen patients who had a final diagnosis of CPN were classified as cases, and 15 patients who lacked a final diagnosis of CPN neuropathy were classified as controls. Morphological characteristics of the CPN, including nerve T2 signal intensity, nerve size, nerve course, fascicles morphology, regional muscle edema, and fatty infiltration, and an overall assessment of the CPN as being normal or abnormal were evaluated by 2 independent radiologists blinded to the clinical history. Overall sensitivity, specificity, and accuracy compared against our reference standards were expressed as percentages. Interobserver agreements were assessed using linear weighted κ statistics. RESULTS: Common peroneal nerve T2 signal abnormality had the highest sensitivity (77%) in identifying CPN neuropathy. Except for T2 signal abnormality, overall specificity for the nerve morphological parameters and muscle denervation change assessed was fairly high, ranging from 94% to 100%. The consensus accuracy ranged from 68% to 79% for the morphological characteristics assessed. The interobserver reproducibility was very good (k = 0.90 to 0.91) for assessment of regional muscle denervation changes and moderate (k = 0.46 to 0.59) for morphological CPN characteristics. CONCLUSION: Magnetic resonance neurography is a useful modality in supplementing the diagnosis of CPN. Using predefined classification criteria helps standardize the morphological criteria of CPN neuropathy diagnosis.

Multimodality correlations of patellar height measurement on X-ray, CT, and MRI.

PURPOSE: To investigate whether the universally accepted range of normal patellar height ratios derived from radiography for the Insall-Salvati (IS) and Blackburne-Peel (BP) methods could be similarly applied to both CT and MRI. MATERIALS AND METHODS: Institutional review board approval was obtained with waiver of informed consent for this HIPPA-compliant study. A total of 45 knees in 42 patients (15 men, 27 women; age range 11 to 75 years, mean age 39 ± 20 years) who underwent tri-modality (radiograph, CT, and MRI) examinations were selected. All patients had knee imaging obtained for a variety of reasons and measurements were performed by two independent readers who were blinded to each other's measurements or the respective measurements derived from each of the methods. Paired t test was used to compare the mean values among the modalities. Inter-observer and inter-method agreements were assessed using intra-class correlation coefficients. RESULTS: Statistically significant, but small quantitative differences are noted between tri-modality patellar height ratios. For comparable results, the small addition of 0.13 and 0.10 are needed for the Insall-Salvati measurements on MRI and CT respectively, compared with radiographs. For the Blackburne-Peel ratio, an additional adjustment of 0.09 is needed between radiographs and MRI, but not between radiographs and CT. These adjustments are independent of gender. The interobserver reproducibility was excellent (ICC ≥ 0.94) for both the Insall-Salvati and Blackburne-Peel methods for all modalities. CONCLUSION: The results indicate that cut-off values for patella alta and baja derived from radiographs should not be directly transposed to CT and MRI; however, the adjustments are relatively minor. These measurements show excellent reproducibility for all modalities currently used for patellar height measurements.

3 Tesla MR neurography--technique, interpretation, and pitfalls.

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.

Magnetic resonance neurography-surgical correlation of neurologic thoracic outlet syndrome.

For evaluation of thoracic outlet syndrome (TOS), 3 Tesla magnetic resonance neurography (MRN) is being increasingly used. The authors report the findings on 3 T MRN with surgical correlation in a rare case of neurologic TOS caused by anomalous costal pseudoarthrosis.