FIGURE 1.
Flow diagram for this study
DWI = diffusion-weighted imaging; HDR-BT = high-dose-rate brachytherapy; NR-Mets = non-responding metastases; R-Mets = responding metastases; HDR-BT = high-dose-rate brachytherapy
TABLE 1.
Quantitative and qualitative results on baseline, 1. follow up and 2. follow up after local therapy of colorectal liver metastases with brachytherapy
| Target lesions | Responding metastases | Non-responding metastases | ||||
|---|---|---|---|---|---|---|
| Baseline | 1. follow-up | 2. follow-up | Baseline | 1. follow-up | 2. follow-up | |
| Size (cm) | 2.2 +/− 1.2 | 1.7 +/− 0.9 | 1.0 +/−0.4 | 4.1 +/− 2.2 | 3.3 +/− 2.0 | 4.1 +/− 2.3 |
| ADCmean | 0.84 +/− 0.34 | 1.44 +/− 0.19 | 1.48+/− 0.44 | 1.21 +/− 0.34 | 1.49 +/− 0.35 | 1.28 +/− 0.32 |
| ADCmin | 0.44 +/− 0.24 | 0.82 +/− 0.25 | 0.9 +/− 0.38 | 0.44 +/− 0.23 | 0.54 +/− 0.41 | 0.4 +/− 0.32 |
| Visually diffusion restriction | 11/18 (61.11%) | 2/18 (11.11%) | 0/18 (0%) | 8/11 (72.38%) | 4/11 (36.36%) | 8/11 (72.38%) |
| Intraindividual increase in | between baseline and 1. follow-up | between baseline and 2. follow up | between baseline and 1. follow-up | between baseline and 2. follow up | ||
| ADCmean (%) | 175 | 187 | 127 | 106 | ||
| ADCmin (%) | 208 | 281 | 146 | 115 | ||
FIGURE 2.
Mean apparent diffusion coefficient (ADCmean) change in responding metastases (R-Mets) and NR-Mets between preinterventional MRI and first and second follow-up, respectively
ADC = apparent diffusion coefficient; NR-Mets = non-responding metastases, R-Mets = responding metastases
FIGURE 3.
R-Met in a 62-year-old female. The pre-interventional diffusion-weighted imaging (DWI) shows two diffusion-restricted liver metastases with high signal on axial diffusion-weighted (DW)-MR image b = 800 s/mm2 (A) and low signal on apparent diffusion coefficient (ADC) map (B). The pre-interventional ADCmean of the metastases were 0.83 and 0.86 x 10−3 mm2/s. In the hepatobiliary phase (C) both metastases showed a hypointense signal. After high-dose-rate brachytherapy (HDR-BT), the metastases demonstrated a hyperintense signal on the axial DW-MR image (D) and a hyperintense signal on the ADC map (E) indicating less restricted diffusion compared to the pre-interventional image. The ADCmean increased to 1.41 and 1.53 x 10−3 mm2/s. in the hepatobiliary phase (F). The lesion showed central necrosis with a peripheral post-radiogenic hypointense rim. In the second follow-up the lesions showed no restricted diffusion (G) with a further increasing ADC (H) value of 2.09 and 2.07 x 10−3 mm2/s. There was a shrinkage in size of the metastases without a new hypointense defect in the hepatobiliary phase (I).
FIGURE 4.
Non-responding metastases (NR-met) in a 56-year-old male. In preinterventional MRI, metastasis (circle) shows restricted diffusion (A+B) with an mean apparent diffusion coefficient (ADCmean) of 0.86 x 10−3 mm2/s and a hypointense pattern on the liver-specific phase (C). Three months after high-dose-rate brachytherapy (HDR-BT), the metastasis showed visually partial restricted diffusion (D+E), but, with an increasing ADCmean of 1.52 x 10−3 mm2/s and hypointensity in the hepatobiliary phase (F). After 11 months, the lesion increased in size, shows a visually an increasing diffusion restriction (K+L) at the boarder (arrow) with a persistently ADCmean value of 1.53 x 10−3 mm2/s and a new defect in the hepatobiliary phase (arrow) (I) indicating local tumor recurrence.