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Type III washout kinetics on dynamic contrast-enhanced breast MRI (DCE-MRI) refers to a time–intensity curve (TIC) pattern where the lesion shows:

• Rapid initial contrast enhancement, followed by
• Subsequent decrease (“washout”) in signal intensity in delayed phases. </aside>

This pattern is highly suggestive of malignancy, representing aggressive tumor vascular characteristics and high microvessel permeability.

![DCE-MRI characteristics in two malignancies with different levels of microvessel density: Top row: a 44-year old woman with biopsy-proven grade II invasive ductal carcinoma. a DCE-MRI demonstrates an enhancing lesion in the subareolar region of the left breast (arrow). b Kinetics analysis shows rapid contrast enhancement and washout, with predominantly high signal enhancement ratio (SER), with peak SER = 2.1 (initial peak percent enhancement [PE] = 310%, functional tumor volume [FTV] = 4.9 cm3, and washout fraction [WF] = 56%; red indicates areas of washout [SER ≥ 1.1]). c Plot of overall lesion enhancement (%) versus time after contrast injection demonstrates high early peak enhancement and washout by 8 min. d Histologic staining for CD31 indicates high microvessel density (MVD; shown at ×400 magnification), with mean vessel count = 56. Bottom row: a 34-year old woman with biopsy-proven grade III invasive ductal carcinoma. e DCE-MRI demonstrates an enhancing lesion in the posterior right breast. f Kinetics analysis shows predominantly low SER, with peak SER = 1.3 (initial peak PE = 218%, FTV = 4.8 cm3, and WF = 6%)), with mean vessel count = 9. g Plot of overall lesion enhancement (%) versus time after contrast injection demonstrates persistent enhancement over 8 min. h Histologic staining for CD31 indicates low MVD (shown at ×400 magnification).

Xiao, J., Rahbar, H., Hippe, D.S. et al. Dynamic contrast-enhanced breast MRI features correlate with invasive breast cancer angiogenesis. npj Breast Cancer 7, 42 (2021). https://doi.org/10.1038/s41523-021-00247-3

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DCE-MRI characteristics in two malignancies with different levels of microvessel density: Top row: a 44-year old woman with biopsy-proven grade II invasive ductal carcinoma. a DCE-MRI demonstrates an enhancing lesion in the subareolar region of the left breast (arrow). b Kinetics analysis shows rapid contrast enhancement and washout, with predominantly high signal enhancement ratio (SER), with peak SER = 2.1 (initial peak percent enhancement [PE] = 310%, functional tumor volume [FTV] = 4.9 cm3, and washout fraction [WF] = 56%; red indicates areas of washout [SER ≥ 1.1]). c Plot of overall lesion enhancement (%) versus time after contrast injection demonstrates high early peak enhancement and washout by 8 min. d Histologic staining for CD31 indicates high microvessel density (MVD; shown at ×400 magnification), with mean vessel count = 56. Bottom row: a 34-year old woman with biopsy-proven grade III invasive ductal carcinoma. e DCE-MRI demonstrates an enhancing lesion in the posterior right breast. f Kinetics analysis shows predominantly low SER, with peak SER = 1.3 (initial peak PE = 218%, FTV = 4.8 cm3, and WF = 6%)), with mean vessel count = 9. g Plot of overall lesion enhancement (%) versus time after contrast injection demonstrates persistent enhancement over 8 min. h Histologic staining for CD31 indicates low MVD (shown at ×400 magnification).

Xiao, J., Rahbar, H., Hippe, D.S. et al. Dynamic contrast-enhanced breast MRI features correlate with invasive breast cancer angiogenesis. npj Breast Cancer 7, 42 (2021). https://doi.org/10.1038/s41523-021-00247-3

Principle of DCE-MRI

DCE-MRI evaluates lesion vascularity and permeability by repeatedly acquiring T1-weighted images before and after IV administration of gadolinium contrast.

Rationale:

Malignant lesions induce tumor angiogenesis, producing leaky, immature vessels with increased permeability and perfusion, resulting in rapid uptake and washout of contrast.

Time–Signal Intensity Curve (TIC) Analysis

After contrast injection, enhancement is plotted as signal intensity (Y-axis) versus time (X-axis).

DCE-MRI curve interpretation involves two phases:

1. Initial (early) enhancement phase — within first 1–2 minutes.
2. Delayed (post-initial) phase — typically 2–7 minutes after injection.

The Three Standard Enhancement Curve Types (per ACR BI-RADS MRI Lexicon)

![Illustration of the different types of kinetic curves from DCE MRI: Type I is a progressive enhancement pattern that shows a continuous increase in signal intensity over time. The Type II curve has a plateau pattern where there is initial contrast-molecule uptake followed by a plateau phase and the result is suggestive of malignant tumor. The Type III curve is a washout pattern where there is initial rapid uptake followed by reduction in signal enhancement and it is strongly suggestive of malignancy.

Mayrhofer RM, Ng HP, Putti TC, Kuchel PW. Magnetic Resonance in the Detection of Breast Cancers of Different Histological Types. Magnetic Resonance Insights. 2013;6. doi:10.4137/MRI.S10640](attachment:bc1260fb-2788-4631-be7a-968ff3493c72:10.4137_mri.s10640-fig2.jpg)

Illustration of the different types of kinetic curves from DCE MRI: Type I is a progressive enhancement pattern that shows a continuous increase in signal intensity over time. The Type II curve has a plateau pattern where there is initial contrast-molecule uptake followed by a plateau phase and the result is suggestive of malignant tumor. The Type III curve is a washout pattern where there is initial rapid uptake followed by reduction in signal enhancement and it is strongly suggestive of malignancy.

Mayrhofer RM, Ng HP, Putti TC, Kuchel PW. Magnetic Resonance in the Detection of Breast Cancers of Different Histological Types. Magnetic Resonance Insights. 2013;6. doi:10.4137/MRI.S10640

Type III (“Washout”) Kinetics – Key Features