Dynamic multi-echo DCE- and DSC-MRI in rectal cancer: Low primary tumor K^trans and ΔR2* peak are significantly associated with lymph node metastasis

Abstract

Purpose: To implement a dynamic contrast-based multi-echo MRI sequence in assessment of rectal cancer and evaluate associations between histopathologic data and the acquired dynamic contrast-enhanced (DCE) and dynamic susceptibility contrast (DSC) -MRI parameters. Materials and Methods: This pilot study reports results from 17 patients with resectable rectal cancer. Dynamic contrast-based multi-echo MRI (1.5T) was acquired using a three-dimensional multi-shot EPI sequence, yielding both DCE-and DSC-data following a single injection of contrast agent. The Institutional Review Board approved the study and all patients provided written informed consent. Quantitative analysis was performed by pharmacokinetic modeling on DCE data and tracer kinetic modeling on DSC data. Mann-Whitney U-test and receiver operating characteristics curve statistics was used to evaluate associations between histopathologic data and the acquired DCE-and DSC-MRI parameters. Results: For patients with histologically confirmed nodal metastasis, the primary tumor demonstrated a significantly lower K trans and peak change in R Ã 2 , R Ã 2 -peak enh , than patients without nodal metastasis, showing a P-value of 0.010 and 0.005 for reader 1, and 0.043 and 0.019 for reader 2, respectively. Conclusion: This study shows the feasibility of acquiring DCE-and DSC-MRI in rectal cancer by dynamic multi-echo MRI. A significant association was found between both K trans and R Ã 2 -peak enh in the primary tumor and histological nodal status of the surgical specimen, which may improve stratification of patients to intensified multimodal treatment.

Association between high-resolution MRI-detected extramural vascular invasion and tumour microcirculation estimated by dynamic contrast-enhanced MRI in rectal cancer: preliminary results

“…The K trans value represents the transfer rate from plasma to the EES, which has a mixed microcirculatory blood flow and permeability weighting [15, 28]. Although a mixed situation occurs most commonly, there is an overall trend of a dominating effect of flow in untreated tumours [29].…”

“…A recent study also showed that primary rectal cancer blood flow measured by DCE-MRI was significantly lower in patients with metastatic nodes, which also represents an unfavourable prognosis [28]. However, regarding the investigation by Yu et al [26], lymphovascular invasion was correlated with higher K trans , k ep and v e values.…”

Comparison of Intravoxel incoherent motion imaging and multiecho dynamic contrast‐based MRI in rectal cancer

“…As for the DSC analysis, a linear relationship was assumed between the change in R 1 = 1/T 1 and CA concentration, and an average precontrast T 1 -value measured from six patients was used (1350 msec in tissue). 9 The extended Tofts (ET) model 18 was fitted to the data with the equation:…”

“…DSC‐MRI is a CA‐based method whereby the T 2 *‐ (susceptibility) effect, rather than the T 1 ‐effect of the CA, is utilized to measure perfusion‐related metrics. DSC‐MRI has mainly been used in the brain due to dominant T 2 *‐effects in regions with an intact blood–brain barrier, but has recently also shown utility in staging of rectal cancer . Specifically addressing brain tumors, Bisdas et al found good correlation between perfusion measured by DSC‐MRI and IVIM‐derived metrics but generally poorer correlation between DCE‐MRI‐derived metrics and IVIM.…”

“…DSC-MRI has mainly been used in the brain due to dominant T 2 *-effects in regions with an intact bloodbrain barrier, 8 but has recently also shown utility in staging of rectal cancer. 9 Specifically addressing brain tumors, Bisdas et al 10 found good correlation between perfusion measured by DSC-MRI and IVIM-derived metrics but generally poorer correlation between DCE-MRI-derived metrics and IVIM. Also, for applications outside the central nervous system (CNS), the correlations between IVIM and DCE-MRIderived metrics are generally unclear.…”