Osteoid Osteoma Mimicking Arthritis.

ABSTRACT: Intra-articular osteoid osteoma may simulate arthritis, due to the intra-articular presence of prostaglandin, which leads to synovitis, joint effusion, pain, and high local temperature. Also, intra-articular osteoid osteoma may present with minimum or no cortical thickening. Therefore, a high suspicion is needed for a correct and early diagnosis. Perfusion weighted imaging, such as dynamic contrast-enhanced imaging, can aid in the localization of the tumor nidus, seen as an early arterial-phase focal enhancement after the gadolinium injection, with fast washout, as a result of its hypervascularity.

"Million dollar nerve" magnetic resonance neurography: first normal and pathological findings.

OBJECTIVES: To evaluate prospectively the feasibility of magnetic resonance neurography (MRN) in identifying the anatomical characteristics of thenar muscular branch (TMB) of the median nerve, also known as the "million dollar nerve," in patients and controls. METHODS: Thirteen patients affected by carpal tunnel syndrome (CTS) and four healthy controls had their hands scanned on a 3-T MR imaging scanner for TMB visualization. Median nerve anatomical variations were classified into four groups according to Poisel's classification system modified by Lanz. TMB signal intensity and diameter were assessed for the diagnosis of neuropathy. RESULTS: TMB was successfully identified in all patients and subjects by using MRN. The most suitable pulse sequences to identify and measure nerve diameter were 3D DW-PSIF and T2-FS-TSE. The axial oblique and sagittal oblique planes are complementary in demonstrating its entire course. TMB had mostly an extraligamentous course with radial side origin (93.8%, each). All patients experienced increased T2 signal intensity (p < 0.001) and thickened nerves. Mean TMB diameters were 1.27 ± 0.21 mm (range, 1.02-1.74 mm) and 0.87 ± 0.16 mm (0.73-1.08 mm) (p = 0.008) in the patient and control groups, respectively. CONCLUSION: MRN is a reliable imaging technique for identification and anatomical characterization of TMB in patients affected by CTS. This innovative imaging workup may therefore be included in the preoperative evaluation of patients scheduled for carpal tunnel release, especially in CTS with TMB involvement or even in isolated TMB neuropathy. KEY POINTS: • Magnetic resonance neurography allows precise visualization of the thenar muscular branch of the median nerve. • Thenar muscular branch anatomical variations can be correctly identified. • Preoperative scanning can contribute to reducing the risk of iatrogenic injuries during carpal tunnel release, especially in carpal tunnel syndrome with thenar muscular branch involvement or even in isolated thenar muscular branch neuropathy.

Updating on Bone and Soft Tissue Sarcomas Staging.

Bone and soft tissue sarcomas consist of a heterogeneous group of malignant tumors of mesenchymal origin that can affect patients from any age. The precise staging of these lesions determines the best therapeutic strategies and prognosis estimates. Two staging systems are the most frequently used: the system proposed by the University of Florida group, led by Dr. William F. Enneking (1980) and adopted by the Musculoskeletal Tumor Society (MSTS), and the system developed by the American Joint Committee on Cancer (AJCC) (1977), currently in its 8 th edition (2017). This paper updates the reader on the staging of bone and soft tissue sarcomas affecting the musculoskeletal system.

Multiparametric MR Imaging of Soft Tissue Tumors and Pseudotumors.

This article discusses the features of multiparametric MR imaging as an accurate method to evaluate soft tissue tumors and pseudotumors. The discussion also considers conventional and advanced sequences providing both functional tissue and anatomic information to improve the diagnostic accuracy of this method and assess pretreatment staging, treatment response focused on the extent of necrosis, and recurrence.

Advanced MR Imaging and Ultrasound Fusion in Musculoskeletal Procedures.

Neoplastic musculoskeletal lesions are heterogeneous tumors with variable outcomes that require a precise diagnosis and delivery of optimal, specific treatment. Advanced MR imaging techniques can help differentiate and characterize musculoskeletal soft tissue tumors and are the method of choice for detection, evaluation, local staging, and surgical planning. MR imaging-ultrasound fusion is the process of combining relevant information from 2 methods into a single image that is more informative than the images obtained separately. This article assesses the potential of fusing real-time ultrasound spatial registration with previously acquired musculoskeletal MR imaging to guide tumor tissue biopsies and procedures.

Whole-body magnetic resonance imaging for the assessment of metastatic breast cancer.

Breast cancer is the most common type of tumor in women and an important cause of mortality in the female population. The early and precise diagnosis, staging, and treatment of this neoplasia are essential for public health purposes. Technological development, for example, of whole-body magnetic resonance imaging, made possible the adoption of new imaging modalities for a better approach for these patients. This imaging modality is helpful to staging, to therapy response assessment, and to the study of therapeutic changes in bone marrow, because it gives, at the same time, anatomical information using T1- and T2-weighted images, with high spatial resolution and tissue contrast, as well as functional sequences (diffusion-weighted images), which make possible the detection of hypercellular viable tumors.

The usefulness of chemical-shift magnetic resonance imaging for the evaluation of osteoid osteoma.

OBJECTIVE: The purpose of this study was to determine whether chemical-shift magnetic resonance imaging (MRI) could be useful in the diagnosis of osteoid osteoma when clinical and radiological tumor features are inconclusive. MATERIALS AND METHODS: This retrospective study included 17 patients who underwent chemical-shift MRI for the evaluation of osteoid osteoma. For all patients, two musculoskeletal radiologists independently recorded signal intensities on in-phase and out-of-phase images in the nidus of the tumor, in abnormal-intensity bone marrow surrounding the lesion, and in normal-appearing bone marrow. For each region, relative signal intensity ratios were calculated by dividing out-of-phase by in-phase values. Relative ratios > 1 were considered indicative of neoplastic lesions. Statistical analysis was carried out to analyze the sample. Inter-observer and intra-observer agreement for each imaging method were assessed using intraclass correlation coefficients according to the Fleiss method and a value > 0.65 was considered to indicate substantial agreement. RESULTS: The mean relative signal intensity ratios were 1.2 (range, 0.9-1.4) for the nidus and 0.35 (range, 0.11-0.66) for the surrounding tissue; these values differed significantly from the relative signal-intensity ratios for normal-appearing bone marrow (p < 0.05). CONCLUSION: Chemical-shift MRI is useful for the diagnosis and evaluation of osteoid osteoma.