Kambiz Motamedi

Thermal Ablation of Osteoid Osteoma: Overview and Step-by-Step Guide

Osteoid osteoma is a small, benign but painful lesion with specific clinical and imaging characteristics. Computed tomography is the imaging modality of choice for visualization of the nidus and for treatment planning. Complete surgical excision of the nidus is curative, providing symptomatic relief, and is the traditionally preferred treatment. However, surgery has disadvantages, including the difficulty of locating the lesion intraoperatively, the need for prolonged hospitalization, and the possibility of postoperative complications ranging from an unsatisfactory cosmetic result to a fracture. Percutaneous radiofrequency (RF) ablation, which involves the use of thermal coagulation to induce necrosis in the lesion, is a minimally invasive alternative to surgical treatment of osteoid osteoma. With reported success rates approaching 90%, RF ablation should be considered among the primary options available for treating this condition.

Revisiting CT-Guided Percutaneous Core Needle Biopsy of Musculoskeletal Lesions: Contributors to Biopsy Success

OBJECTIVE The purpose of this article is to investigate potential technical, imaging, and histopathologic contributors to the success of CT biopsy. MATERIALS AND METHODS Four hundred forty-four consecutive CT biopsies of musculoskeletal lesions performed from 2005 to 2008 were retrospectively classified as diagnostic or nondiagnostic and as accurate or inaccurate. A biopsy was considered as diagnostic if it provided a definitive pathologic diagnosis or was clinically useful; as accurate if it was concordant with the ultimate diagnosis with respect to identification of malignancy, grade, and histopathologic features; and as successful if it was both diagnostic and accurate. Biopsy success rate, diagnostic yield, and accuracy were assessed according to lesion location, use of sedation, biopsy equipment type, bone lesion matrix type, and lesion histologic type (i.e., bone or soft-tissue origin, malignant or benign neoplasm, and low-or intermediate-to-high-grade neoplasm). RESULTS Of 444 biopsies, 71% were diagnostic, 86% were accurate, and 70% were successful. Biopsy success and diagnostic yield were greater in bone lesions, malignant neoplasms, and intermediate-to-high-grade neoplasms compared with soft-tissue lesions (p < 0.01), benign neoplasms (p < 0.0001), and low-grade neoplasms (p < 0.0001). Success and diagnostic yield were not significantly associated with technical or imaging factors. Biopsy accuracy was not associated with any of the tested variables. Of the 128 nondiagnostic biopsy results, 53% were accurate with respect to subsequent surgical pathologic findings. Most of these biopsy results were of benign soft-tissue lesions. CONCLUSION CT biopsy of musculoskeletal lesions is accurate and effective. It may be limited in the evaluation of benign and low-grade soft-tissue neoplasms.

Benign bone tumors.

A solid knowledge of underlying histopathology of benign bone tumors aids in differential diagnoses of these tumors. Important factors in diagnosis of a bone tumor include patient age and gender; the bone involved; the location of the tumor along, within, or on the bone; lesion margin; matrix proliferation; and periosteal reaction. This article provides a review of the origin of the tumor matrix and its influence on the imaging properties of these tumors.

Does Dual-Energy CT of Lower-Extremity Tendons Incur Penalties in Patient Radiation Exposure or Reduced Multiplanar Reconstruction Image Quality?

OBJECTIVE The purposes of this study were to evaluate the quality and radiation exposure of data acquired with dual-energy CT compared with single-energy MDCT in the depiction of lower-extremity tendons and to assess whether a dual-energy CT voltage exists at which the quality of tendon depiction is optimal. SUBJECTS AND METHODS Eleven healthy volunteers and seven clinically referred patients (10 men, eight women; mean age, 43.1 years; range, 20-71 years) underwent conventional single-energy CT and dual-energy CT examinations of both lower extremities with a dual-source CT scanner. Dual-energy reconstructions were made at combined tube voltages approximating 86, 98, 110, 122, and 134 kVp. Quantitative and qualitative analyses were performed on six tendons in each lower extremity, and the findings were compared with single-energy CT findings. The radiation dose involved was recorded in each case. RESULTS A trend toward increasing tendon attenuation was observed with increasing reconstructed tube voltage. The group of single-energy CT reconstructions proved significantly superior to each of the dual-energy CT reconstructions with regard to signal-to-noise ratio (F = 35.25, p < 0.0001) and contrast-to-noise ratio (F = 37.19, p < 0.0001), although interobserver agreement in subjective ranking was poor. Dual-energy CT had a significantly higher radiation dose (p < 0.05) than single-energy CT. CONCLUSION Dual-energy CT of lower-extremity tendons, irrespective of the reconstruction tube voltage chosen, yields multiplanar reformations inferior to those of single-energy CT with regard to signal-to-noise and contrast-to-noise ratios while involving significantly escalated patient exposure to ionizing radiation. Whether the tissue-differentiating promise of dual-energy CT is realized in future studies and warrants such concessions remains to be seen.

CT of Rib Lesions

OBJECTIVE This article discusses how ribs are involved in a variety of traumatic, metabolic, inflammatory, neoplastic, and congenital disorders. CONCLUSION We review the normal anatomy pertinent to rib imaging and illustrate the key features of a variety of rib lesions, emphasizing the diagnostic value of CT.

Comprehensive appraisal of magnetic resonance imaging findings in sustained rheumatoid arthritis remission: A substudy

Objective To evaluate the effect of sustained ACR/EULAR Boolean remission on residual joint inflammation assessed by magnetic resonance imaging (MRI) and to secondarily evaluate other clinical definitions of remission, within an early seropositive rheumatoid arthritis (RA) cohort.To evaluate the effect of sustained American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) Boolean remission on residual joint inflammation assessed by magnetic resonance imaging (MRI) and to secondarily evaluate other clinical definitions of remission, within an early seropositive rheumatoid arthritis (RA) cohort.

Image-guided Percutaneous Core Needle Biopsy of Musculoskeletal Tumors in Children

The use of image-guided percutaneous core needle biopsy (PCNB) to obtain tissue diagnosis of musculoskeletal lesions has become the standard of care in adult patients with a success rate of over 80%. Previous reports indicate a similar success rate in diagnosing pediatric solid tumors. In this large study, we analyzed >10 years of data in which PCNB was used for tissue diagnosis of musculoskeletal lesions in children; we evaluated the histopathologic accuracy, anesthetic requirements, and complications of these procedures. In 122 children, tissue diagnosis was successfully obtained in 82% of cases, and there were 0 complications associated with the procedure. There was a significantly higher PCNB diagnostic success rate in malignant lesions (93%). These data suggest that the use of PCNB is a safe and effective means of diagnosing musculoskeletal lesions in children.

Imaging of the shoulder: a comparison of MRI and ultrasound.

Magnetic resonance imaging (MRI) is well established as a powerful imaging modality for the shoulder. In the last decade, ultrasound has emerged as an effective imaging option, alongside MRI, for evaluation of the shoulder. With MRI and ultrasound, clinicians now have two viable advanced imaging options for the diagnostic evaluation of shoulder pain. This article discusses the advantages and disadvantages of ultrasound and MRI for the shoulder. Applications where ultrasound is considered the imaging test of choice, those where MRI is more advantageous, and those where both ultrasound and MRI are viable alternatives for shoulder imaging are discussed.

Osteochondral Lesions in Pediatric and Adolescent Patients

Osteochondral lesions are acquired, potentially reversible injuries of the subchondral bone with or without associated articular cartilage involvement. Injury results in delamination and potential sequestration of the affected bone. Although an association with mechanical and traumatic factors has been established, the etiology remains poorly understood. These lesions commonly occur in the knee; articular surfaces of the elbow, ankle, hip, and shoulder are also affected. Osteochondral lesions are relatively common in children and adolescents, and the incidence is increasing. Prognosis of these lesions depends on stability, location, and size of the lesion.Imaging has an essential role in the diagnosis, staging, and management of osteochondral lesions. Many of these lesions are first diagnosed by plain film. MRI adds value by identifying unstable lesions that require surgical intervention. This review focuses on the clinical and imaging features of osteochondral lesions of the knee, elbow, and ankle. Imaging criteria for staging and management are also reviewed.

Tophaceous gout of the first costochondral junction in a heart transplant patient

We report the case of a 49-year-old man with a 10-year history of gout, who presented with a painful left first costochondral junction mass. A computed tomography (CT)-guided biopsy of the mass revealed foreign body giant cell reaction and crystalline deposition consistent with tophaceous gout.