Imaging evaluation of musculoskeletal tumors

Imaging Analyses of Bone Tumors

Despite the evolution in imaging, especially the introduction of advanced imaging technologies, radiographs still are the key for the initial assessment of a bone tumor. Important aspects to be considered in radiographs are the location, shape and size or volume, margins, periosteal reaction, and internal mineralization of the tumor's matrix; careful evaluation of these may provide for accurate diagnosis in >80% of cases. Computed tomography and magnetic resonance imaging are often diagnostic for lesions with typical findings such as the nidus of osteoid osteoma and bone destruction such as in Ewing sarcoma and lymphoma that may be difficult to detect with radiographs; they may also be used for surgical planning. Magnetic resonance imaging accurately determines the intraosseous extent and articular and vascular involvement by the tumor. This article summarizes the diagnostic accuracy of imaging analyses in bone tumors and emphasizes the specific radiographic findings for optimal radiographic diagnosis of the patients with these tumors.

3D computed tomography angiography as a novel post-processing approach in diagnosis of pediatric malignant bone tumors

OBJECTIVE

This study aimed to investigate the application of 3D computed tomography (CT) angiography with a novel post-processing technique in diagnosis of malignant bone tumors in children.

METHODS

Twenty-seven pediatric patients (15 males and 12 females; average age: 10±3.4 years old, with a range from 2 months to 14 years old) with suspected bone tumors were evaluated histopathologically using 3D CT angiography and a multislice scanner. CT angiography image data were analyzed with a novel post-processing technique that included separating, fusing opacifying false-coloring, and volume rendering.

RESULTS

Among 27 cases, 20 (74%) osteosarcoma, 6 (22%) Ewing's sarcoma, and 1 (4%) non-Hodgkin lymohoma were diagnosed by histological examination of surgical specimens. The tumor features, including size, location, invasion into the adjacent tissue as well as distant metastases, were clearly visualized with the regular volume rendering method and rotational and stereoscopical videos. The post-processing technique provided the reconstructed structure images without any overlap or shelter independently and collectively. Special colors represented different tissue structures, aiding in identification of various anatomical structures and pre-surgical planning.

CONCLUSIONS

Compared to traditional 3-D CT methods, 3-D CT angiography with rotational and stereoscopical videos provides more detailed information of bone tumor lesions. It offers a superior and effective imaging technique in pediatric patients with malignant bone tumors.

A prospective study comparing whole-body skeletal X-ray survey with 18F-FDG-PET/CT, 18F-NaF-PET/CT and whole-body MRI in the detection of bone lesions in multiple myeloma patients

Background

For decades, the most widely used imaging technique for myeloma bone lesions has been a whole-body skeletal X-ray survey (WBXR), but newer promising imaging techniques are evolving.

Purpose

To compare WBXR with the advanced imaging techniques 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT), 18F-sodium fluoride (NaF) PET/CT and whole-body magnetic resonance imaging (WB-MRI) in the detection of myeloma bone lesions.

Material and Methods

Fourteen patients with newly diagnosed multiple myeloma were prospectively enrolled. In addition to WBXR, all patients underwent FDG-PET/CT, NaF-PET/CT, and WB-MRI. Experienced specialists performed blinded readings based on predefined anatomical regions and diagnostic criteria.

Results

In a region-based analysis, a two-sided ANOVA test showed that the extent of detected skeletal disease depends on the scanning technique (P < 0.0001). Tukey’s multiple comparison test revealed that WB-MRI on average detects significantly more affected regions than WBXR (P < 0.005), FDG-PET/CT (P < 0.0001), and NaF-PET/CT (P < 0.05). In a patient-based analysis, a Cochran’s Q test showed that there are no significant differences in the proportion of patients with bone disease detected by the different scanning techniques (P = 0.23). Determination of intrareader variability resulted in Kappa coefficients corresponding to moderate (FDG-PET/CT) and substantial agreement (WB-MRI, WBXR, NaF-PET/CT).

Conclusion

WB-MRI detects on average significantly more body regions indicative of myeloma bone disease compared to WBXR, FDG-PET/CT, and NaF-PET/CT. The lack of significance in the patient-based analysis is most likely due to the small number of study participants.

Musculoskeletal Imaging Findings of Hematologic Malignancies

Hematologic malignancies comprise a set of prevalent yet clinically diverse diseases that can affect every organ system. Because blood components originate in bone marrow, it is no surprise that bone marrow is a common location for both primary and metastatic hematologic neoplasms. Findings of hematologic malignancy can be seen with most imaging modalities including radiography, computed tomography (CT), technetium 99m (^99mTc) methylene diphosphonate (MDP) bone scanning, fluorine 18 (¹⁸F) fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT, and magnetic resonance (MR) imaging. Because of the diversity of imaging appearances and clinical behavior of this spectrum of disease, diagnosis can be challenging, and profound understanding of the underlying pathophysiologic changes and current treatment modalities can be daunting. The appearance of normal bone marrow at MR imaging and FDG PET/CT is also varied due to dynamic compositional changes with normal aging and in response to hematologic demand or treatment, which can lead to false-positive interpretation of imaging studies. In this article, the authors review the normal maturation and imaging appearance of bone marrow. Focusing on lymphoma, leukemia, and multiple myeloma, they present the spectrum of imaging findings of hematologic malignancy affecting the musculoskeletal system and the current imaging tools available to the radiologist. They discuss the imaging findings of posttreatment bone marrow and review commonly used staging systems and consensus recommendations for appropriate imaging for staging, management, and assessment of clinical remission. ^©RSNA, 2017.

Diagnosis of bone metastasis from thyroid carcinoma: a multidisciplinary approach

Sarcomas are rare tumors originating from soft tissue or bone. Diagnosis and treatment of sarcomas should be performed at specialized sarcoma centers, where patients are evaluated at a multidisciplinary tumor conference. We present a case where sarcoma was suspected from magnetic resonance imaging (MRI), but histology revealed a metastasis from thyroid carcinoma, although the patient had no previous history of thyroid malignancy and resection of the thyroid gland was without malignancy. Ultrasound-guided biopsy was possible due to cortical destruction and the multidisciplinary approach with re-evaluation of previous pathology and a thorough patient history enabled a final diagnosis.