The Evolution of Musculoskeletal Tumor Imaging

Update in Imaging Evaluation of Bone and Soft Tissue Sarcomas

The evolution in imaging evaluation of musculoskeletal sarcomas contributed to a significant improvement in the prognosis and survival of patients with these neoplasms. The precise characterization of these lesions, using the most appropriate imaging modalities to each clinical condition presented, is of paramount importance in the design of the therapeutic approach to be instituted, with a direct impact on clinical outcomes. The present article seeks to update the reader regarding imaging methodologies in the context of local and systemic evaluation of bone sarcomas and soft tissues.

Magnetic resonance imaging in differentiating between aggressive and non-aggressive bone tumors

BACKGROUND

While radiography remains essential in the initial evaluation of bone lesions, tissue biopsy or further imaging is often required to clarify indeterminate radiographic features. Magnetic resonance imaging (MRI) assists radiologists in evaluating lesions with indeterminate features as it has advantages in delineating tumorous tissues and bone marrow.

PURPOSE

To evaluate the association factors of MRI for bony aggressiveness.

MATERIAL AND METHODS

A retrospective analysis of 226 MRI examinations from patients diagnosed with bone tumors in a tertiary hospital during 2008-2018 was performed. All the MR images were interpreted by musculoskeletal radiologists without diagnostic information. The bony lesions were categorized into aggressive and non-aggressive groups using tumor margin, cortical changes, periosteal reaction, joint extension, extraosseous soft tissue involvement, tumor homogeneity, and enhancement pattern from the MR images. Univariable and multivariable analysis were applied for each feature on the MRI scans. In addition, sensitivity and specificity were calculated for MRI diagnoses of aggressive bone lesions.

RESULTS

In total, 180 aggressive and 46 non-aggressive bone lesions were examined on MRI. The sensitivity and specificity of MRI for differentiating between aggressive and non-aggressive bone lesions were 98.89% and 50%, respectively. Ill-defined margin, cortical break, cortical signal changes, sunburst and Codman's triangle periosteal reaction, joint extension, and tumoral and heterogeneous enhancement could be predictive signs for aggressive bone lesions.

CONCLUSION

MRI can be a valuable tool to assist in distinguishing aggressive from non-aggressive bone lesions. In cases of indeterminate radiographic features, MRI could be used as an additional imaging to improve diagnostic accuracy and could reduce unnecessary invasive procedures.

New challenges in integrated diagnosis by imaging and osteo-immunology in bone lesions

INTRODUCTION

High-resolution imaging is the gold standard to measure the functional and biological features of bone lesions. Imaging markers have allowed the characterization both of tumour heterogeneity and metabolic data. Besides, ongoing studies are evaluating a combined use of 'imaging markers', such as SUVs, MATV, TLG, ADC from PET and MRI techniques respectively, and several 'biomarkers' spanning from chemokine immune-modulators, such as PD-1, RANK/RANKL, CXCR4/CXCL12 to transcription factors, such as TP53, RB1, MDM2, RUNX family, EZH2, YY1, MAD2. Osteoimmunology may improve diagnosis and prognosis leading to precision medicine in bone lesion treatment. Areas covered: We investigated modalities (molecular and imaging approach) useful to identify bone lesions deriving both from primary bone tumours and from osteotropic tumours, which have a higher incidence, prevalence and prognosis. Here, we summarized the recent advances in imaging techniques and osteoimmunology biomarkers which could play a pivotal role in personalized treatment. Expert commentary: Although imaging and molecular integration could allow both early diagnosis and stratification of cancer prognosis, large scale clinical trials will be necessary to translate pilot studies in the current clinical setting.

ABBREVIATIONS

ADC: apparent diffusion coefficient; ALCAM: Activated Leukocyte Cell Adhesion Molecule; ALP: Alkaline phosphatases; BC: Breast cancer; BSAP: B-Cell Lineage Specific Activator; BSAP: bone-specific alkaline phosphatase; BSP: bone sialoprotein; CRIP1: cysteine-rich intestinal protein 1; CD44: cluster of differentiation 44; CT: computed tomography; CXCL12: C-X-C motif ligand 12; CXCR4: C-X-C C-X-C chemokine receptor type 4; CTLA-4: Cytotoxic T-lymphocyte antigen 4; CTX-1: C-terminal end of the telopeptide of type I collagen; DC: dendritic cell; DWI: Diffusion-weighted MR image; EMT: mesenchymal transition; ET-1: endothelin-1; FDA: Food and Drug Administration; FDG: ¹⁸F-2-fluoro-2-deoxy-D-glucose; FGF: fibroblast growth factor; FOXC2: forkhead box protein C2: HK-2: hexokinase-2; ICTP: carboxyterminal cross-linked telopeptide of type I collagen; IGF-1R: Insulin Like Growth Factor 1 Receptor; ILC: innate lymphocytes cells; LC: lung cancer; IL-1: interleukin-1; LYVE1: lymphatic vessel endothelial hyaluronic acid receptor 1; MAD2: mitotic arrest deficient 2; MATV: metabolically active tumour volume; M-CSF: macrophage colony stimulating factor; MM: multiple myeloma; MIP1a: macrophage inflammatory protein 1a; MSC: mesenchymal stem cell; MRI: magnetic resonance imaging; PC: prostate cancer; NRP2: neuropilin 2; OPG: osteoprotogerin; PDGF: platelet-derived growth factor; PD-1: Programmed Cell Death 1; PET: positron emission tomography; PINP: procollagen type I N propeptide; PROX1: prospero homeobox protein 1; PSA: Prostate-specific antigen; PTH: parathyroid hormone; RANK: Receptor activator of NF-kB ligand; RECK: Reversion-inducing-cysteine-rich protein; SEMAs: semaphorins; SPECT: single photon computed tomography; SUV: standard uptake value; TLG: total lesion glycolysis; TP53: tumour protein 53; VCAM-1: vascular endothelial molecule-1; VOI: volume of interest; YY1: Yin Yang 1.

Analysis of imaging characteristics of primary malignant bone tumors in children

The present study aimed to investigate the imaging characteristics of primary malignant bone tumors in children. The imaging results of 34 children with primary malignant bone tumors confirmed by histopathological diagnosis between March 2008 and January 2014 were retrospectively analyzed. In total, 25 patients had osteosarcoma, with radiography and computed tomography (CT) showing osteolytic bone destruction or/and osteoblastic bone sclerosis, an aggressive periosteal reaction, a soft-tissue mass and cancerous bone. The tumors appeared as mixed magnetic resonance imaging (MRI) signals that were inhomogeneously enhanced. A total of 5 patients presented with Ewing sarcoma, with radiography and CT showing invasive bone destruction and a soft-tissue mass. Of the 5 cases, 2 showed a laminar periosteal reaction. The tumors were shown to have mixed low signal on T1-weighted images (T1WI) and high signal on T2-weighted images (T2WI); 1 case showed marked inhomogeneous enhancement. Another 3 patients exhibited chondrosarcoma. Of these cases, 1 was adjacent to the cortex of the proximal tibia, and presented with local cortical bone destruction and a soft-tissue mass containing scattered punctate and amorphous calcifications. MRI revealed mixed low T1 signal and high T2 signals. Another case was located in the medullary cavity of the distal femur, with radiography revealing a localized periosteal reaction. The tumor appeared with mixed MRI signals, and with involvement of the epiphysis and epiphyseal plates. Radiography and CT of the third case showed bone destruction in the right pubic ramus, with patchy punctate, cambered calcifications in the soft-tissue mass. MRI of the soft-tissue mass revealed isointensity on T1WI and heterogeneous hyperintensity on T2WI. Ossifications and the septum appeared as low T1WI and T2WI. Of the 34 patients, 1 patient presented with lymphoma involving the T12, L1 and L2 vertebrae. CT showed vertebral bone destruction, a soft-tissue mass and a compression fracture of L1. MRI showed a soft-tissue mass with low T1 signal and high T2 signal and marked inhomogeneous enhancement. Overall, osteosarcoma was the most common primary malignant bone tumor, followed by Ewing sarcoma, chondrosarcoma and lymphoma. Osteoblastic or osteolytic bone destruction, an invasive periosteal reaction, soft-tissue masses, a tumor matrix and inhomogeneous enhancement were important imaging features of malignant bone tumors.

ACR Appropriateness Criteria Follow-Up of Malignant or Aggressive Musculoskeletal Tumors

Appropriate imaging modalities for the follow-up of malignant or aggressive musculoskeletal tumors include radiography, MRI, CT, (18)F-2-fluoro-2-deoxy-D-glucose PET/CT, (99m)Tc bone scan, and ultrasound. Clinical scenarios reviewed include evaluation for metastatic disease to the lung in low- and high-risk patients, for osseous metastatic disease in asymptomatic and symptomatic patients, for local recurrence of osseous tumors with and without significant hardware present, and for local recurrence of soft tissue tumors. The timing for follow-up of pulmonary metastasis surveillance is also reviewed. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed every three years by a multidisciplinary expert panel. The guideline development and review include an extensive analysis of current medical literature from peer-reviewed journals and the application of a well-established consensus methodology (modified Delphi) to rate the appropriateness of imaging and treatment procedures by the panel. In those instances in which evidence is lacking or not definitive, expert opinion may be used to recommend imaging or treatment.

Multi-detector computed tomography in evaluating locally aggressive and malignant bone tumours

OBJECTIVE

To evaluate the ability of Multi-Detector Computed Tomography in preoperative evaluation of locally aggressive and malignant bone tumours in correlation with histopathological findings.

MATERIALS AND METHODS

Twenty patients suspected of malignant bone tumours on the basis of their clinical profile were selected. Following a plain radiograph evaluation, all of them were subjected to CT scan examination. Multi Planar Reconstruction (MPR) was done in sagittal and coronal planes and also three-dimensional Volume Rendering (VR) and Maximum Intensity Projection (MIP) images were obtained.

RESULTS

Of the 20 patients, 18 underwent surgery, and their histopathological findings were compared and correlated with MDCT findings. MDCT was 92.8% sensitive and 100% specific in determining the vascularity of the tumour and also can detect displacement/ encasement/ involvement of adjacent vessels. It has a sensitivity and specificity of 100% in determining cortical break, calcification and periosteal reaction. However, it is less sensitive in detecting joint involvement. Post contrast enhancement gives details of the extent of the soft tissue component.

CONCLUSION

Although MRI is a preferred modality in preoperative evaluation of bone tumours, CT may be used an alternative in case of non-availability of MRI, which has faster acquisition time and better resolution. Using three dimensional MPR imaging, the location and extent of the tumour can be studied. It is also useful in determining cortical discontinuity, periosteal reaction, and calcification. By virtue of MIP and VR imaging, vascularity of the tumour and its relationship with the adjacent vasculature can be established. However, it is inferior to MRI in soft tissue characterization and has poor sensitivity in detecting marrow and joint involvement.

Ultrasonography of soft tissue "oops lesions"

In this article, I would like to define “oops lesions” as soft tissue mass-like lesions that involve surprise or embarrassment for radiologists following the final diagnosis. Examples of “oops lesions” include malignant tumors that appear benign, malignancy-mimicking benign tumors, incorrect identification of epidermal inclusion cysts, and soft tissue pseudotumors. Ultrasonography (US) findings are very helpful in the diagnosis of soft tissue tumors; however, the diagnosis of soft tissue tumors on the basis of US findings alone has some limitations. Therefore, clinical findings, laboratory data, findings from additional imaging modalities, and demographic data of patients should be considered together with US findings.

Bone tumor imaging, then and now: review article

BACKGROUND

Musculoskeletal tumor imaging is a focused subspecialty of musculoskeletal radiology. The goals of imaging and techniques employed are continually evolving and often slightly different from those used in other musculoskeletal diseases. As these techniques change, it is occasionally useful to review what is new.

QUESTIONS/PURPOSES

The question addressed in this manuscript is what are the most interesting/relevant changes in each modality of musculoskeletal tumor imaging over the past 38 years, the length of time the newly emeritus chair of the Radiology and Imaging Department of Hospital for Special Surgery has been at the hospital.

METHODS

This review is primarily expert opinion based in examining techniques used at the institutions of the authors, with support from current literature.

RESULTS

The techniques of computed tomography (CT) and magnetic resonance imaging (MRI) are new to the imaging armamentarium, and ultrasound and nuclear medicine techniques have advanced considerably with technology. Although radiographs have also evolved, the changes are less apparent, except in how they are currently processed, viewed, and stored.

CONCLUSIONS

Radiographic evaluation is still critical to evaluating bone tumors. Newer techniques also play an important role in diagnosing and treating these neoplasms.

Benign bone tumors

Benign bone lesions are a broad category that demonstrates a spectrum of activities from latent to aggressive. Differentiating the various tumors is important in order to properly determine necessary intervention. This chapter focuses on the presentation, imaging, diagnostic features, and treatment of the most common benign bone tumors in order to help guide diagnosis and management.

Imaging evaluation of musculoskeletal tumors

In this chapter, we review different imaging modalities, including radiography, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and nuclear medicine scintigraphy, and their application to musculoskeletal neoplasm. Advantages and limitations of each modality are reviewed, and suggestions for imaging approach are provided.

Imaging review of skeletal tumors of the pelvis--part I: benign tumors of the pelvis

The osseous pelvis is a well-recognized site of origin of numerous primary and secondary musculoskeletal tumors. The radiologic evaluation of a pelvic lesion often begins with the plain film and proceeds to computed tomography (CT), or magnetic resonance imaging (MRI) and possibly biopsy. Each of these modalities, with inherent advantages and disadvantages, has a role in the workup of pelvic osseous masses. Clinical history and imaging characteristics can significantly narrow the broad differential diagnosis for osseous pelvic lesions. The purpose of this review is to familiarize the radiologist with the presentation and appearance of some of the common benign neoplasms of the osseous pelvis and share our experience and approach in diagnosing these lesions.

The role of imaging for translational research in bone tumors

Sarcomas are a heterogeneous group of rare connective tissue tumors, representing 1% of adult and 15% of childhood cancers for which biological and pathological information is still incomplete. In bone tumors patients with metastatic disease at onset, those who relapse and those with post-surgical secondary lesions still have a dismal outcome because of poor response to current therapies. Different molecular biology approaches have identified activated cell signalling pathways or specific molecular endpoints that may be considered potential drug targets or markers useful for diagnosis/prognosis in musculoskeletal pathology. Recently, advances in the field of molecular imaging allow visualization of cell and metabolic functions with the use of targets that include cell membrane receptors, enzymes of intracellular transport. Moreover advanced non-invasive newer imaging techniques like 18-FDG PET, quantitative dynamic-contrast MR imaging, diffusion weighted imaging have all shown a potential in distinguish malignant from benign lesions, in revealing the efficacy of therapy in tumors, the onset of recurrence and a good reliability in reckoning the percentage of necrosis in Ewing sarcoma and osteosarcoma. Thus, in vivo detection of imaging cancer biomarkers may be useful to better characterize those complex pathologic processes, such as apoptosis, proliferation and angiogenesis that determine tumor aggressiveness, providing not only complementary information of prognostic metabolic indicators, but also data in real-time on the efficacy of the treatment through the modulation of the cell metabolism.

A signal-inducing bone cement for magnetic resonance imaging-guided spinal surgery based on hydroxyapatite and polymethylmethacrylate

The aim of this study was to develop a signal-inducing bone cement for magnetic resonance imaging (MRI)-guided cementoplasty of the spine. This MRI cement would allow precise and controlled injection of cement into pathologic lesions of the bone. We mixed conventional polymethylmethacrylate bone cement (PMMA; 5 ml methylmethacrylate and 12 g polymethylmethacrylate) with hydroxyapatite (HA) bone substitute (2-4 ml) and a gadolinium-based contrast agent (CA; 0-60 μl). The contrast-to-noise ratio (CNR) of different CA doses was measured in an open 1.0-Tesla scanner for fast T1W Turbo-Spin-Echo (TSE) and T1W TSE pulse sequences to determine the highest signal. We simulated MRI-guided cementoplasty in cadaveric spines. Compressive strength of the cements was tested. The highest CNR was (1) 87.3 (SD 2.9) in fast T1W TSE for cements with 4 μl CA/ml HA (4 ml) and (2) 60.8 (SD 2.4) in T1W TSE for cements with 1 μl CA/ml HA (4 ml). MRI-guided cementoplasty in cadaveric spine was feasible. Compressive strength decreased with increasing amounts of HA from 46.7 MPa (2 ml HA) to 28.0 MPa (4 ml HA). An MRI-compatible cement based on PMMA, HA, and CA is feasible and clearly visible on MRI images. MRI-guided spinal cementoplasty using this cement would permit direct visualization of the cement, the pathologic process, and the anatomical surroundings.