Is contrast necessary for spinal MRI to assess for metastases?

From the Guidelines

Contrast is typically necessary for spinal MRI to assess for metastases, as it improves the detection of small metastatic lesions, helps differentiate between benign and malignant lesions, and allows better visualization of the extent of tumor involvement. The standard protocol for evaluating spinal metastases includes both non-contrast and contrast-enhanced MRI sequences, with the contrast agent usually being gadolinium-based, administered intravenously at a dose of 0.1 mmol/kg body weight 1.

Key points for implementation:

• Perform non-contrast T1-weighted and T2-weighted sequences first.
• Administer gadolinium contrast.
• Obtain post-contrast T1-weighted sequences with fat suppression. Contrast enhancement is crucial because:
• It improves the detection of small metastatic lesions.
• It helps differentiate between benign and malignant lesions.
• It allows better visualization of the extent of tumor involvement.
• It can reveal leptomeningeal spread of disease. The contrast agent highlights areas of abnormal vascularity and blood-brain barrier disruption, which are characteristic of metastatic lesions, making them appear brighter on T1-weighted images, standing out against the background of normal tissue and allowing for more accurate diagnosis and staging 1.

In patients suspected of having cancer, MRI without and with IV contrast is considered superior in evaluation of localizing disease (intramedullary, intradural-extramedullary, and extradural) as well as assessing extent of the lesion 1. Although CT lumbar spine without IV contrast can be performed to evaluate osseous integrity (eg, pathologic fracture) when involved with tumor, intradural and spinal cord pathologies are poorly depicted on CT, and MRI offers greater specificity than bone scan, with comparable sensitivity and the added advantage of providing anatomic detail 1.

From the FDA Drug Label

Gadoterate Meglumine Injection is a gadolinium-based contrast agent indicated: for intravenous use with magnetic resonance imaging (MRI) in brain (intracranial), spine and associated tissues in adult and pediatric patients (including term neonates) to detect and visualize areas with disruption of the blood brain barrier (BBB) and/or abnormal vascularity.

The use of contrast, specifically gadoterate meglumine, is indicated for MRI of the spine to detect and visualize areas with disruption of the blood brain barrier and/or abnormal vascularity, which can be associated with metastases.

• Key points:
  • The drug label indicates the use of contrast for spinal MRI.
  • The contrast agent is used to detect and visualize areas with disruption of the blood brain barrier and/or abnormal vascularity. 2 2

From the Research

Assessment of Spinal Metastases using MRI

The use of contrast in spinal MRI for assessing metastases is a topic of interest in the medical field. Several studies have investigated the role of contrast-enhanced MRI in detecting spinal metastases.

• A systematic review and meta-analysis 3 found that MRI had the highest diagnostic accuracy for spinal metastases detection, with a pooled sensitivity of 93% and specificity of 85%.
• A study on dynamic contrast-enhanced MRI (DCE-MRI) 4 found that it can discriminate between hypervascular and hypovascular spinal metastases, which has important clinical implications.
• Another review 5 highlighted the utility of DCE-MRI in assessing tumor viability and differentiating between malignant and benign vertebral compression fractures.
• A study on MRI sequences for detecting bone-marrow metastases in neuroblastoma 6 found that the combination of non-contrast-enhanced T1-weighted and gadolinium-enhanced T1-weighted sequences can be used to determine the presence of spinal metastases.
• However, a study 7 found that adding contrast-enhanced MRI to conventional MRI was useful in only 39-53% of cases, and there were no clinical or radiological factors that could predict the usefulness of contrast-enhanced MRI.

Role of Contrast in Spinal MRI

The evidence suggests that contrast-enhanced MRI can be useful in detecting and characterizing spinal metastases, particularly in certain cases.

• DCE-MRI can provide valuable information on tumor vascularity and viability 4, 5.
• However, the use of contrast is not always necessary, and non-contrast-enhanced sequences can also be effective in detecting spinal metastases 6, 7.
• The decision to use contrast-enhanced MRI should be based on individual patient factors and the specific clinical context.