Simultaneous compression and speckle reduction of clinical breast and fetal ultrasound images using rate-fidelity optimized coding

Medical ultrasound images are inherently noised with speckle noise, which may interfere with Computer Aided Diagnostics (CAD) tasks, such as automatic segmentation. A compression and speckle de-noising method is proposed and tested on real clinical breast and fetal ultrasound images. The proposed algorithm is based on the optimization of quantization coefficients when applying Wavelet representation on the image, where the optimization is held such that a pre-defined mathematical fidelity criterion with respect to a desired de-speckled image is obtained. The proposed algorithm yields effective speckle reduction whilst preserving the edges in the images, with a reduced computational burden compared to other existing state-of-the-art methods, such as Optimal Bayesian Non-Local Means (OBNLM). In addition, the images are simultaneously compressed to a target bit-rate. The proposed algorithm is evaluated using both objective mathematical fidelity criteria (such as Structural Similarity and Edge Preserve) as well as subjective radiologists tests. The experimental results demonstrate the ability of the proposed method to achieve de-speckled images with compression ratios of approximately 30:1, whilst obtaining competitive subjective as well as objective fidelity measures with respect to the desired de-speckled images.

Chemotherapy may eradicate ductal carcinoma in situ (DCIS) but not the associated microcalcifications

INTRODUCTION

We studied the effect of neoadjuvant chemotherapy (NAC) ± trastuzumab on the ductal carcinoma in situ (DCIS) component in patients with locally advanced breast cancer who achieved pathological complete response (pCR).

METHODS

The diagnostic biopsies of 92 consecutive breast cancer patients that were treated with neoadjuvant chemotherapy (NAC) ± trastuzumab were evaluated for the presence of DCIS. Upon completion of NAC, the surgical specimens were evaluated for complete eradication of both the invasive and non-invasive cancer in the breast. The pretreatment mammograms were evaluated for the presence of microcalcifications and compared to the mammograms that were obtained upon completion of therapy prior to surgery.

RESULTS

Thirty of 92 patients (33%) had a substantial component of DCIS in the pretreatment biopsy. Thirty nine patients (42%) achieved pCR: 22 (56%) following NAC + trastuzumab, 17 (32%) following chemotherapy only. Ten of 30 patients (33%) with DCIS component achieved pCR: 4 received chemotherapy only, in 6 trastuzumab was added. Multiple microcalcifications on the pretreatment mammograms were observed in 3 of 10 patients with DCIS who achieved pCR. No reduction in the area of calcifications was observed following NAC.

CONCLUSIONS

DCIS may be completely eradicated by NAC ± trastuzumab. However, associated microcalcifications probably persist. Patients with locally advanced breast cancer with substantial DCIS may still opt for NAC and breast conservation as the DCIS component may respond and even completely disappear following NAC. Residual widespread microcalcifications after NAC do not necessarily indicate residual cancer. Larger studies are needed to direct the surgical management of these patients.