CT Chest with Intravenous Contrast
For a large, non-mobile mass centrally located on the back between the scapulae, order a contrast-enhanced CT of the chest (thorax) to definitively characterize the lesion, determine its relationship to surrounding structures, and guide further management.
Rationale for Contrast-Enhanced CT
The location you describe—between the scapulae—suggests either a chest wall mass, a posterior mediastinal mass, or the classic presentation of elastofibroma dorsi. CT with IV contrast is the imaging modality of choice because it provides superior spatial resolution, can distinguish tissue planes, demonstrates enhancement patterns that differentiate vascular from avascular components, and identifies invasion into adjacent structures 1.
Key Diagnostic Considerations
The differential diagnosis for this location includes:
Elastofibroma dorsi: The most common benign mass in this specific location, appearing as an elongated, incompletely marginated soft tissue density deep to the inferior angle of the scapula, with characteristic elevation of the latissimus dorsi muscle 2. This is pathognomonic when bilateral and in the classic subscapular location.
Chest wall tumors: Including soft tissue sarcomas or benign tumors arising from muscle, fascia, or bone
Posterior mediastinal masses: Though less likely given the "non-mobile" description suggesting chest wall fixation
Pleural-based masses: Such as solitary fibrous tumors, which show marked heterogeneous enhancement and intratumoral vessels 3
Why Contrast is Essential
Contrast enhancement is critical because it:
- Reveals the degree and pattern of enhancement, helping distinguish hypervascular from hypovascular lesions
- Identifies feeding vessels and blood supply patterns (arterial vs venous phase imaging)
- Demonstrates invasion into chest wall, pleura, or mediastinal structures 1
- Differentiates solid enhancing components from cystic or necrotic areas
Without contrast, you lose the ability to characterize tissue vascularity and may miss subtle invasion patterns that affect surgical planning.
Technical Specifications
Order the study as: "CT chest with IV contrast" or "Contrast-enhanced CT thorax"
The radiologist will typically perform:
- Arterial and venous phase imaging for vascular lesions
- Thin-slice reconstruction for detailed anatomic assessment
- Multiplanar reformats to evaluate chest wall and scapular relationships
When to Consider MRI
MRI chest should be reserved as a complementary study if CT findings are indeterminate, particularly for:
- Distinguishing complicated cysts from solid lesions
- Better soft tissue contrast resolution when evaluating chest wall or neurovascular invasion 1, 4
- Assessing relationship to neural foramina if posterior mediastinal involvement is suspected
However, start with contrast-enhanced CT first—it remains the primary imaging modality and will be sufficient in most cases 1, 5.
Common Pitfall
Do not order non-contrast CT for a soft tissue mass evaluation. The lack of enhancement information severely limits tissue characterization and may necessitate repeat imaging with contrast, exposing the patient to additional radiation without diagnostic benefit.