Reaching a Diagnosis
What are Symptoms, Signs, and Treatment Options for Sarcoma
Diagnostic Imaging Techniques
X-ray Imaging (Plain Radiographs)
Plain radiographs are the initial imaging tests conducted upon presentation.
They are straightforward, quick, and involve lower radiation compared to computed tomography.
Plain radiographs provide detailed information about the tumor’s nature, stage, progression, its impact on the surrounding bone or soft tissue, the host’s response to the tumor, and help determine the surgical approach.
Computed Tomography (CT)
CT scans offer enhanced visualization of bone anatomy, cortical continuity, cancellous bone integrity, and periosteal reactions.
Although more expensive than plain radiographs and involving higher radiation exposure, CT scans provide superior detail.
CT scans are particularly advantageous for axial imaging.
They are used for staging, particularly in the thorax/chest to detect metastasis (HRCT).
Ultrasound can aid in characterizing soft tissue tumors by distinguishing solid components from cystic ones.
It can serve as a guidance tool for biopsy of soft tissue tumors, facilitating the targeting of the solid tumor site to aid in pathological diagnosis.
Ultrasound is also employed as an adjunct in the diagnosis of bone and soft tissue tumors.
Magnetic Resonance Imaging (MRI)
MRI is the most comprehensive and informative imaging modality for local staging of bone tumors.
It offers several advantages, including no ionizing radiation, superior contrast, multi-planar display, and improved tissue delineation.
The soft tissue contrast provided by MRI is particularly valuable, allowing for differentiation between adjacent structures.
The addition of gadolinium contrast or enhanced (diffusion-weighted) MRI can further aid in narrowing down the diagnosis.
MRI can detect certain lesions within the same limb, known as “skip lesions” or satellite lesions.
It also assists in measuring the extent of the tumor and aids in reconstruction.
Bone and soft tissue sarcomas can spread regionally and distantly, known as “metastasis.”
The most common site of spread is the lungs, followed by bones and other organs.
Staging involves assessing the spread of sarcoma to other parts of the body, and PET-CT has become a crucial tool in this process.
The most commonly performed PET-CT is 18-FDG (fluorodeoxyglucose), followed by 18-NaF (sodium fluoride) PET-CT for staging purposes.