A study was conducted to determine the accuracy, reproducibility, and reliability of unenhanced magnetic resonance (MR) imaging methods for spotting metastatic axillary lymph nodes in patients with newly diagnosed breast carcinoma. Sixty-one female patients with invasive carcinoma were included in the study. Two radiologists analyzed axial T1-weighted MR images without fat saturation and diffusion-weighted (DW) MR images; the radiologists were blinded to the histopathologic findings. Visual and quantitative analyses of unenhanced MR images were carried out, and sensitivity, specificity, and accuracy were measured. Axial T1-weighted MR imaging exhibited 88 percent sensitivity, 82 percent specificity, and 85 percent accuracy, while those measures for DW imaging were 84 percent, 77 percent, and 80 percent, respectively. Apparent diffusion coefficients (ADCs) were substantially lower in the malignant group, and the average Lin coefficient comparing the average ADC reading for each observer was 0.959, implying very high interobserver correspondence between the two observers in terms of reproducibility of ADCs. However, the conclusion was that although the accuracies of DW and axial T1-weighted MR imaging are high, they are likely not high enough to be useful in clinical practice. The study was published online Dec. 5 in the journal Radiology.
From “Accuracy of Unenhanced MR Imaging in the Detection of Axillary Lymph Node Metastasis: Study of Reproducibility and Reliability”
Radiology (12/05/11) Scaranelo, Anabel M.; Eiada, Riham; Jacks, Lindsay M.; et al.