Samenvatting
Purpose/Introduction:
An accurate assessment of the Tumor Blood Flow (TBF) can become crucial for breast cancer management. Earlier studies
have demonstrated the feasibility of quantifying perfusion parameters in human breast tumors using a deconvolution analysis of DCE-MRI. However, the TBF values were on average higher than the literature PET values. Earlier in myocardium, it has been shown that a prebolus method will allow the use of high concentrations of contrast agent for tissue analysis, in combination with a lower concentration bolus to maintain the linearity of AIF signal intensity. The aim of the present study was to evaluate the use of the prebolus technique in a small cohort of breast tumors.
Subjects and Methods:
In vivo perfusion measurements were performed in 23 women with breast tumors on a 1.5 T scanner. The routine MR mammography protocol was applied first. At the slice where tumor enhances maximally, the prebolus protocol was applied 10 minutes later. 1ml of Gd- DTPA solution at 2ml/s was injected at the beginning of a dynamic axial single slice inversion-prepared (IR prepared) TFE acquisition (800 dynamics with a temporal resolution of 0.3s). At the 400th dynamic, a high dose of either 10ml (8 patients, 5 malignant and 3 benign) or 20ml (15 patients, 11 malignant and 4 benign) of contrast agent was injected at 2ml/s and a further 400 dynamics were acquired. ROIs were placed manually over the aorta and the region within the breast lesion with highest enhancement. From the prebolus curve, AIFs were reconstructed by time-shifting and adding the prebolus response curve until the relevant high dose equivalent was reached. The RE time course from the tumor ROI was then deconvolved to generate the parametric maps.
Results:
Whether the TBF calculation was performed with or without prebolus AIF estimation, the median TBF was higher in malignant tumors compared to the benign ones (p <0.05). The TBF values with prebolus AIF estimation were roughly 2-3 times lower than the corresponding values calculated without it. However, both sets of values were well correlated (Spearman r = 0.84, p <0.05).
Discussion/Conclusion:
Compared to our earlier methodology of using a single large bolus, addition of a low dose prebolus achieves a better contrast
agent concentration estimate in the aorta, while the subsequent high dose guarantees sufficient SNR in tumor tissues. The mean TBF values with the prebolus technique are in agreement with the PET based values.
An accurate assessment of the Tumor Blood Flow (TBF) can become crucial for breast cancer management. Earlier studies
have demonstrated the feasibility of quantifying perfusion parameters in human breast tumors using a deconvolution analysis of DCE-MRI. However, the TBF values were on average higher than the literature PET values. Earlier in myocardium, it has been shown that a prebolus method will allow the use of high concentrations of contrast agent for tissue analysis, in combination with a lower concentration bolus to maintain the linearity of AIF signal intensity. The aim of the present study was to evaluate the use of the prebolus technique in a small cohort of breast tumors.
Subjects and Methods:
In vivo perfusion measurements were performed in 23 women with breast tumors on a 1.5 T scanner. The routine MR mammography protocol was applied first. At the slice where tumor enhances maximally, the prebolus protocol was applied 10 minutes later. 1ml of Gd- DTPA solution at 2ml/s was injected at the beginning of a dynamic axial single slice inversion-prepared (IR prepared) TFE acquisition (800 dynamics with a temporal resolution of 0.3s). At the 400th dynamic, a high dose of either 10ml (8 patients, 5 malignant and 3 benign) or 20ml (15 patients, 11 malignant and 4 benign) of contrast agent was injected at 2ml/s and a further 400 dynamics were acquired. ROIs were placed manually over the aorta and the region within the breast lesion with highest enhancement. From the prebolus curve, AIFs were reconstructed by time-shifting and adding the prebolus response curve until the relevant high dose equivalent was reached. The RE time course from the tumor ROI was then deconvolved to generate the parametric maps.
Results:
Whether the TBF calculation was performed with or without prebolus AIF estimation, the median TBF was higher in malignant tumors compared to the benign ones (p <0.05). The TBF values with prebolus AIF estimation were roughly 2-3 times lower than the corresponding values calculated without it. However, both sets of values were well correlated (Spearman r = 0.84, p <0.05).
Discussion/Conclusion:
Compared to our earlier methodology of using a single large bolus, addition of a low dose prebolus achieves a better contrast
agent concentration estimate in the aorta, while the subsequent high dose guarantees sufficient SNR in tumor tissues. The mean TBF values with the prebolus technique are in agreement with the PET based values.