Imaging for Tongue Mass
For a tongue mass, MRI of the neck without and with IV contrast is the recommended initial imaging modality, as it provides superior soft tissue characterization essential for defining tumor extent, depth of invasion, and treatment planning. 1
Primary Recommendation: MRI Neck Without and With IV Contrast
MRI is the imaging modality of choice for tongue masses because of its superior soft tissue contrast resolution, which allows precise delineation of tumor extent within the intrinsic tongue musculature and assessment of critical features including 1:
- Deep tissue extension and marrow involvement - essential for accurate T staging 1
- Perineural tumor spread - a key prognostic factor that MRI detects better than other modalities 1
- Floor of mouth anatomy - MRI accurately depicts this region, which is imperative for preoperative staging 1
- Absence of dental amalgam artifact - a major advantage over CT in the oral cavity 2, 3
Why Contrast Administration is Essential
Combined pre- and postcontrast imaging provides the best opportunity to correctly identify and delineate the primary tumor. 1 Contrast administration specifically aids in 1:
- Detecting subtle mass extension and invasion of surrounding structures
- Identifying perineural tumor spread
- Accurately delineating tumor margins for surgical planning
- Detecting regional lymph node involvement and extranodal extension
When CT May Be Added
CT neck with contrast should be added if mandibular involvement is suspected based on clinical examination or MRI findings, as CT is superior for detecting cortical bone invasion. 4 CT shows cortical bone invasion as interruption or erosion of the peripheral hyperattenuating rim, while MRI is better for medullary bone invasion (appearing as low-signal-intensity within hyperintense marrow fat). 4
Practical Imaging Protocol Considerations
The standard imaging protocol should extend from skull base to thoracic inlet to adequately capture all structures and screen for additional disease. 1
Key advantages of MRI for tongue masses include 2, 3:
- Multiplanar capabilities - direct coronal and sagittal planes aid in recognizing intrinsic tongue musculature and assessing tumor volume
- Superior discrimination between tumor, fat, and muscle compared to CT
- Better assessment of intra- and extraorgan tumor spread 3
Important Caveats
MRI has longer scan times (typically >30 minutes) and may be limited by 1:
- Motion artifact from breathing and swallowing
- Patient inability to remain motionless
- Contraindications such as certain implantable devices (pacemakers, neurostimulators)
- Claustrophobia
In patients who cannot undergo MRI, contrast-enhanced CT is an acceptable alternative, though it provides inferior soft tissue characterization for tongue lesions. 1
Contraindications to Contrast
Contrast administration may need modification in 1:
- Contrast allergy
- Renal insufficiency (risk of nephrogenic systemic fibrosis with gadolinium)
- Pregnancy
However, noncontrast MRI significantly limits the ability to accurately delineate tumor margins and soft tissue extent, which are key components for T staging and surgical planning. 1