Breast MRI Findings: Kinetics

by Michael Roubakha, MD, Fadi Dahoud, and Cheryce Fischer, MD

• Refers to breast lesion enhancement curves, also known as Kuhl enhancement curves
• In addition to the margins of a lesion, the enhancement intensity of a lesion on MRI two minutes or less after contrast administration is the most important feature for lesion diagnosis
• The next most important feature is the qualitative assessment of the enhancement curve¹

There are three possible initial phase curves (in order of least to most concerning):

1. Slow
2. Medium
3. Rapid

There are also three possible late phase curves (in order of least to most concerning):

Type I: Progressive Pattern (Figure 1)

• Continued increase in signal intensity over time
• Usually a benign pattern (83% of lesions)
• Only about 9% of lesions are malignant²
• Sensitivity of 52.2% and specificity of 71%³

Type II: Plateau Pattern (Figure 2)

• Initial uptake followed by leveling off of signal intensity
• Suggestive of malignancy (sensitivity of 42.6% and specificity of 75% for malignancy)³

Type III: Washout Pattern (Figure 3)

• Initial uptake followed by reduced enhancement
• Strongly suggestive of malignancy (specificity of 90.4% and sensitivity of 20.5%)³

Finally, a lack of enhancement does not completely exclude in situ or invasive cancer.

References

1. Macura KJ, Ouwerkerk R, Jacobs MA, Bluemke DA. "Patterns of Enhancement on Breast MR Images: Interpretation and Imaging Pitfalls." RadioGraphics 2006;26(6):1719-1734. DOI:10.1148/rg.266065025
2. Kuhl CK, Mielcareck P, Klaschik S, et al. "Dynamic breast MR imaging: are signal intensity time course data useful for differential diagnosis of enhancing lesions?" Radiology 1999;211:101–110. DOI: 10.1148/radiology.211.1.r99ap38101
3. Bluemke DA, Gatsonis CA, Chen MH, et al. "Magnetic resonance imaging of the breast prior to biopsy." JAMA 2004;292:2735–2742.  DOI: 10.1001/jama.292.22.2735