Inanc Guvenc MD, Abstract Co-Author: Nothing to Disclose

Gary J. Whitman MD, Abstract Co-Author: Nothing to Disclose

Ping Liu, Abstract Co-Author: Nothing to Disclose

Jingfei Ma PhD, Abstract Co-Author: Nothing to Disclose

Basak Erguvan Dogan MD, Presenter: Nothing to Disclose

Our goal was to evaluate the incremental benefit of diffusion-weighted imaging (DWI) over combined conventional precontrast and dynamic contrast-enhanced breast MRI (CMRI) for diagnosis of ipsilateral metastatic axillary lymphadenopathy in patients with newly-diagnosed breast cancer

Breast MRI examinations performed as standard of patient care between August 2010 and December 2010 that included DWI (b = 1000 s/mm2) were retrospectively evaluated. 85 breast cancer patients with pathological verification of axillary lymph node (LN) status (confirmed by needle biopsy, sentinel lymph node biopsy, and axillary lymph node dissection) were identified. Breast cancer size, grade, and tissue prognostic factors were recorded. Ipsilateral axillary LNs were evaluated using morphological criteria on CMRI. ADC values of the index suspicious ipsilateral LNs were obtained and compared to the ADC values of the contralateral axillary LNs. For statistical analysis, recursive partitioning method was utilized to determine the ADC cut-off value. ROC curves and multivariate logistic regression analyses were used, with pathology as the gold standard

Pathology revealed malignant findings in 31%, and benign findings in 69% of the patients. Among prognostic factors, lesion size was strongly associated with ipsilateral axillary metastases (p=0.03). Hormonal markers and cancer histological grade revealed no significant associations with axillary metastases. The sensitivity of CMRI was 79%, specificity 81%, PPV 65%, and the NPV 89%. Using a cut-off ADC value of 0.985 x10-3 mm2/s, DWI yielded a sensitivity of 83%, a specificity of 98%, a PPV of 95%, and a NPV of 93%. The mean ADC value of metastatic lymph nodes (0.89±0.18x10-3 mm2/s) was significantly lower (P<0.0001, two-sample t-test) than the mean ADC value of benign ipsilateral lymph nodes (1.41±0.21 x10-3 mm2/s)

ADC values can help increase the accuracy of CMRI for diagnosing ipsilateral axillary lymph node metastases in patients with breast cancer. An ADC value < 0.985 accurately predicted metastatic involvement with high PPV and a high NPV for axillary lymph nodes that demonstrate suspicious morphology on CMRI

Our findings indicate that DWI significantly improves the noninvasive diagnosis of axillary lymph node metastases in patients with newly-diagnosed breast cancer, and show promise as imaging biomarkers

Guvenc, I, Whitman, G, Liu, P, Ma, J, Dogan, B, DWI Increases Diagnostic Accuracy of Breast MRI for Predicting Axillary Metastases in Breast Cancer Patients.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11002661.html