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Background Information of tumor vascular architecture and hemodynamics is important in treating patients with head and neck tumors (HNTs). The purpose of this study is to investigate the feasibility of non-contrast-enhanced four-dimensional magnetic resonance angiography (non-CE 4DMRA) using arterial spin labeling for anatomical and hemodynamic evaluation of vascularity of head and neck tumors. Results Non-CE 4DMRA images of 15 patients with HNTs were compared with those of contrast-enhanced 4DMRA (CE 4DMRA) by two independent observers. For qualitative evaluation, overall image quality, visualization of arterial branches and main arterial tumor feeders were assessed. For hemodynamic evaluation, signal-intensity-over-time curves within the tumors were compared. The sensitivity of non-CE 4DMRA for the identification of arterial branches and the main arterial tumor feeders was 75 and 20 %, respectively (interobserver agreement, κ = 0.56 and 0.54, respectively), while that of CE 4DMRA was 99 and 95 %, respectively (interobserver agreement, κ = 0.62 and 0.70, respectively). All three arterial/hypervascularized tumors determined on CE 4DMRA showed distinct signal-intensity-over-time curve pattern on non-CE 4DMRA, with distinct peak and wash out phases. Other tumors showed no wash out on non-CE 4DMRA. Conclusions Use of non-CE 4DMRA for the anatomical and hemodynamic evaluation of vascularity of head and neck tumors is feasible, although the technique needs to be improved.

1103 Background: We previously demonstrated the usefulness of SPIO-enhanced MR imaging for the detection of metastases in sentinel nodes localized by computed tomography (CT) lymphography (CT-LG) in patients with breast cancer (Ann Surg Oncol, 2011). These techniques have evolved and we report our most recent results of axillary staging using them. Methods: Previously unreported 87 consecutive patients with breast cancer and clinically negative nodes were enrolled in this study. Sentinel nodes identified by CT-LG were evaluated prospectively using SPIO-enhanced MR imaging. A node was considered non-metastatic if it showed a homogenous low signal intensity and metastatic if the entire node or a focal area did not show a low signal intensity on MR imaging. Sentinel nodes located by CT-LG were removed, and imaging results and histopathological findings were compared. Results: The mean patient age was 54.9 years (range, 34-77). Sentinel nodes were identified by CT-LG and removed successfully in all patients. The mean number of sentinel nodes identified by CT-LG was 1.16 (range, 1-2). Twenty of 22 patients with positive sentinel nodes definitively diagnosed by pathology demonstrated metastases on SPIO-enhanced MR imaging. Fifty-eight of 65 patients with negative sentinel nodes definitively diagnosed by pathology were non-metastatic on imaging studies. The sensitivity, specificity and accuracy of MR imaging for the diagnosis of sentinel node metastases were 91%, 89%, and 90%, respectively. Two patients whose metastases were not detected had micrometastases. No adverse events were associated with either CT or MR imaging. Conclusions: SPIO-enhanced MR imaging provided accurate axillary staging, and therefore sentinel node biopsy may not be necessary for most patients with breast cancer.

Background We previously demonstrated that superparamagnetic iron oxide (SPIO)-enhanced MR imaging is promising for the detection of metastases in sentinel nodes localized by CT-lymphography in patients with breast cancer. The purpose of this study was to determine the predictive criteria of the size of nodal metastases with SPIO-enhanced MR imaging in breast cancer, with histopathologic findings as reference standard. Methods This study included 150 patients with breast cancer. The patterns of SPIO uptake for positive sentinel nodes were classified into three; uniform high-signal intensity, partial high-signal intensity involving ≥50% of the node, and partial high-signal intensity involving 2 mm sentinel node metastases correlated with the area of high-signal intensity, however, a pathologic ≤2 mm sentinel node metastases did not. Conclusions High-signal intensity patterns that are uniform or involve ≥50% of the node are features of nodes with macro-metastases. The area of high-signal intensity correlated with the pathological size of metastases for nodes with metastases >2 mm in this series.