Ultrasound combined with MRI has the potential to enhance the differentiation of benign and malignant breast nonmass-like lesions, according to the results of a study published in Ultrasound in Medicine & Biology. [1]
Nonmass-like lesions in the breast, which do not meet the criteria for classification as masses, are areas characterized by altered echotexture that differs from the surrounding breast tissue and lacks a typical shape. The research conducted by Chinese PLA General Hospital in Beijing found combining ultrasound with MRI proved to be more accurate in making the distinction between benign and cancerous lesions than either is capable of on its own, ultimately boosting diagnostic accuracy.
The research team led by Rui-Lan Niu, MD, noted that each has limitations on its own, which can mean the misidentification of lesions that inevitably lead to more unnecessary biopsies. Niu and his team wanted to test how valuable using an MRI could be to differentiate between benign and cancerous lesions once ultrasound correctly identified them as nonmass-like lesions. The thought was two imaging techniques may prove more useful than one.
To test this theory, the study authors compiled a training data set comprising 180 patients with 183 nonmass-like lesions, of which 88 were benign and 95 were malignant. To compare, another set encompassed 61 patients with 61 lesions, including 30 benign and 31 malignant cases.
The researchers examined the lesions with MRI, ultrasound, and then a combination of both. In both data sets, the combined method proved to be useful in making a diagnosis of cancer. In the training set, the combined approach exhibited statistical significance when compared to MRI or ultrasound alone, with respect to AUC and specificity values (p < 0.001 for both). In the validation set, the combined method outperformed ultrasound alone (p < 0.001) but not MRI alone.
The study revealed that the malignant group had a significantly higher frequency of calcifications than the benign group (p < 0.001). Nonmass-like lessions with calcifications are 5.6 times more likely to be malignant than those without. This is consistent with prior studies that reported approximately 40%–50% of hypo-echoic areas detected on ultrasound with calcifications to be highly associated with malignancy.
“The integrated diagnostic strategy of US combined with MRI exhibited good performance for breast NMLs compared with either modality used alone, which can improve the diagnostic specificity while maintaining high sensitivity,” Niu and the other authors wrote.
The combined method identified two additional false-negative lesions, which were characterized by small size and the absence of typical malignant sonographic features. Moreover, it correctly identified 11 false-positive lesions as benign. Pathology results were confirmed through excision or biopsy.
The study authors do note the results have limitations and that more research is required. Most notably, they cite that the “small sample of nonmass-like lesions from a single center may lead to biased conclusions,” also noting the inherent sample bias in choosing to combine ultrasound with MRI for this study.
The full results can be found by clicking here.
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