Summarizing the 4D image stack of ultrafast dynamic contrast enhancement MRI of breast cancer in 3D using color intensity projections

Abstract

Background Each ultrafast dynamic contrast‐enhanced (DCE) MRI sequence for breast cancer generates thousands of images in a 4D stack that need to be reviewed by a radiologist. Purpose To assess whether color intensity projections (CIP) effectively summarizes—using only the time of arrival (ToA) and amount of signal enhancement (AoE) of the contrast agent—the thousands of ultrafast images. Study Type Retrospective cohort clinical trial. Subjects The study included 89 patients who had been scanned with an MRI beast protocol, of which 26 had breast cancer and 63 did not. Field Strength/Sequence The 115‐second ultrafast DCE sequence at 3T acquired 19 consecutive frames every 4.26 seconds with 152 slices per frame, yielding a 4D stack with 2888 2D images for each of water and fat. Assessment For each slice of the water 4D stack a single CIP image was generated that encoded the ToA in the hue (red, orange, yellow, green, cyan, blue) and AoE in the brightness. Each of three experienced radiologists assigned a Breast Imaging and Reporting Data System (BI‐RADS) score for each patient, first using only the CIP images, and subsequently using both CIP and the full 4D stack. Statistical Tests The one‐sided Fisher's exact test was used to determine statistical significance of both the sensitivity and specificity between the CIP alone and the CIP plus 4D stack. Results All malignancies were detected using only CIP by at least one of the radiologists. The CIP and CIP+4D sensitivities for reader 1 were 96% and 96% (P = 0.57), specificities were 59% and 65% (P = 0.29). For reader 2, the values were 96% and 100% (P = 0.51) with 62% and 71% (P = 0.17). For reader 3 the values were 92% and 96% (P = 0.50) with 51% and 62% (P = 0.07). Data Conclusion With a 95% sensitivity, CIP provides an effective summary of ultrafast DCE images of breast cancer. Level of Evidence: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;49:1391–1399.

The Additional Value of Ultrafast DCE-MRI to DWI-MRI and 18F-FDG-PET to Detect Occult Primary Head and Neck Squamous Cell Carcinoma

“…Although the precise physiological explanation of enhancement on DCE remains ambiguous (e.g., angiogenesis and increased microvessel density) [ 19 ], early intensity changes were indicative for malignancy ( Figure 2 ). This is in line with studies in breast cancer with an earlier time of arrival of contrast bolus in the malignant lesion [ 15 , 16 , 17 ]. Although the thin mucosal hypervascular layer and normal tonsillar tissue might interfere with the detection UPT, no other hypervascular lesions are generally present in the head and neck area.…”

“…Quantification based on delineated region of interest, has been introduced previously in DCE [ 15 , 16 ] in order to optimize detecting occult primary tumors. Although voluminous quantitative parameters did not showed increased accuracy [ 1 ], semi-quantitative parameters describing the area under the curve, time-to-peak or upslope angle might increase detection performance, and should be assessed in future studies.…”

“…Ultrafast-DCE with a high temporal resolution (i.e., <10 s per stack of images) captures details of the first contrast uptake kinetics and increased the diagnostic performance for tumor detection in prostate [ 15 ] and breast cancer [ 16 , 17 ]. The principle of discrimination between benign and malignant lesions is based on the earlier time of arrival of the contrast in malignancies with increased neoangiogenesis or perfusion compared to normal tissue.…”

Is It Possible for MRI Screening of Breast Cancer to be Available to Many More Women by Greatly Reducing its False Positive Detections via Ultrafast Time to Enhancement Measurements?

“…Figure 2 shows a color intensity projection (CIP) of a patient with breast cancer. 5,6 CIP images enable the quick and easy visualization of TTE in the breast by using brightness to display the amount of enhancement and the hue (red, orange, yellow, green, cyan, and blue) to display the TTE for each voxel. Any voxels that enhanced before the aorta are displayed in grayscale.…”

“…FIGURE 2: A color intensity projection (CIP) of a maximum intensity projection (MIP) image generated from the ultrafast sequence images (a) compared to the first post-contrast conventional T1-weighted (T1W) MIP image (b). 5,6 The conventional T1 image shown was acquired about 2 minutes after the contrast agent arrived at the aorta. The hue encodes in each pixel the contrast agent's time to enhancement (TTE) relative to the aortic arch (the time is indicated by the color bar on top).…”