Breast Magnetic Resonance Imaging for Assessment of Internal Mammary Lymph Node Status in Breast Cancer

Abstract

PurposeThe purpose of this study was to assess magnetic resonance imaging (MRI) features of malignant internal mammary lymph nodes (IMLNs) and benign IMLNs in breast cancer patients.MethodsFrom 2009 to 2014, the records of 85 patients with IMLNs were archived using MRI report data; 26 patients with small size (long axis diameter <5 mm) nodes were subsequently excluded. The current study evaluated internal mammary lymph nodes in 59 patients who underwent breast MRI for breast cancer staging and for posttherapy follow-up. All MRI findings were retrospectively evaluated. Malignancy was determined based on pathologic examination and positron emission tomography computed tomography findings. Independent t-tests, Mann-Whitney U tests, chi-square tests, and receiver operating characteristics (ROC) curve analysis were used.ResultsAmong MRI features, there were statistically significant differences between benign and malignant IMLN groups, in short axis length (3.6±1.3 vs. 8.2±2.9 mm, respectively), long axis length (8.1±2.4 vs. 14.5±4.8 mm, respectively), short/long axis ratio (0.45±0.10 vs. 0.59±0.17, respectively), absent fatty hilum (mean, 0% vs. 95%, respectively), and restricted diffusion (15.8% vs. 85.0%, respectively) (p<0.050). Multiplicity and location of intercostal spaces was not different between the two groups. Short axis length was the most discriminative variable for predicting metastatic nodes (area under the ROC curve, 0.951; threshold, 4 mm; sensitivity, 92.5%; specificity, 84.2%).ConclusionConventional MRI and diffusion-weighted MRI are helpful to detect metastasis of internal mammary lymph nodes in breast cancer.

Radiotherapy of MRI-detected involved internal mammary lymph nodes in breast cancer

“…Lee et al demonstrated that malignant IM lymph nodes identified on MRI had a short/long (S/L) axis ratio that was significantly greater than the ratio for benign IM nodes (0.45 ± 0.10 vs 0.59 ± 0.17). [ 21 ] The mean S/L ratio of the 26 nodes identified in our series (0.63 ± 0.19) is consistent with this report. Bellon et al reported on outcomes of seven women with locally advanced breast cancer and increased uptake in the IM nodes seen on positron emission tomography.…”

Optimal radiotherapy for patients with internal mammary lymph node metastasis from breast cancer

“…In previous studies, an IMN diameter of 0.5 cm or larger in breast MRI has been regarded as metastatic IMN [4,14,15]. In a study where MRI findings of IMN were compared with surgically dissected IMN, the IMN of ≥0.5 cm was likely to have malignant cells in pathologic examination with 90.7% accuracy, 93.3% sensitivity, and 89.3% specificity [15].…”

“…In a study where MRI findings of IMN were compared with surgically dissected IMN, the IMN of ≥0.5 cm was likely to have malignant cells in pathologic examination with 90.7% accuracy, 93.3% sensitivity, and 89.3% specificity [15]. Similarly, in a study where IMN metastasis was determined based on pathologic evaluation or PET-CT finding, IMN short-axis length ≥ 0.4 cm was predictive of positive metastasis with 92.5% sensitivity and 84.2% specificity [14]. According to recent studies of physiologic IMN adenopathy incidentally found in healthy females undergoing screening breast MRI, the mean IMN diameter was 0.45 cm [16] or 0.4 cm [17].…”

Heterogeneous Enhancement Pattern in DCE-MRI Reveals the Morphology of Normal Lymph Nodes: An Experimental Study

“…Before the administration of the contrast agent, a standard non-fat-suppressed T1-weighted sequence (multislice RARE with TR/TE: 550/7.6 ms, flip angle: 180°, matrix size: 175 × 100, number of slices: 6, field-of-view: 3.5 × 2.0 mm 2 , slice thickness: 0.5 mm, number of averages: 8, and RARE factor: 8) was applied to investigate the presence of a fatty hilum, which has been often reported in human lymph nodes [24, 25].…”