Photoacoustic mammography: initial clinical results.
ABSTRACT PURPOSE: Photoacoustic tomography can image the hemoglobin distribution and oxygenation state inside tissue with high spatial resolution. The purpose of this study is to investigate its clinical usefulness for diagnosis of breast cancer and evaluation of therapeutic response in relation to other diagnostic modalities. MATERIALS AND METHODS: Using a prototype machine for photoacoustic mammography (PAM), 27 breast tumor lesions, including 21 invasive breast cancer (IBC), five ductal carcinoma in situ (DCIS), and one phyllodes tumor, were measured. Nine out of twenty-one IBC patients had received primary systemic therapy (PST). RESULTS: Eight out of twelve IBC without PST were visible. Notably, detection was possible in all five cases with DCIS, whereas it was not in one case with phyllodes tumor. Seven out of nine IBC with PST were assigned as visible in spite of decreased size of tumor after PST. The mean value of hemoglobin saturation in the visible lesions was 78.6 %, and hemoglobin concentration was 207 μM. The tumor images of PAM were comparable to those of magnetic resonance imaging (MRI). CONCLUSIONS: It is suggested that PAM can image tumor vascularity and oxygenation, which may be useful for diagnosis and characterization of breast cancer.
- SourceAvailable from: Mahesh Iddawela[show abstract] [hide abstract]
ABSTRACT: Pathological complete response (pCR) is an important predictor of long-term survival in patients with breast cancer receiving neoadjuvant chemotherapy (NAC). At present, the accuracy of traditional radiological assessments during treatment in predicting pCR is poor. Unidimensional and 3D volumetric ultrasound measurements prior to, after 4 cycles (mid-treatment), and at the end of 8 cycles (end-treatment) of chemotherapy were available from a subset of 55 patients enrolled in Neo-tAnGo, a National Cancer Research Network (NCRN) UK neoadjuvant chemotherapy breast cancer trial. Proportional changes in longest diameter (LD) and volume as well as absolute residual size thresholds were examined for their ability to predict pCR or pCR plus minimal residual disease (pCR/MRD). Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) and likelihood ratios (LRs) were calculated. Receiver-operator characteristic (ROC) curves and logistic regression models were also constructed. At mid-treatment, neither complete radiological response, nor proportional LD or volume changes were found predictive of final pCR. A small residual tumour volume (≤ 1 cm³ vs. > 1 cm³) at mid-treatment, however, was associated with pCR/MRD (P = 0.014). Sensitivity, specificity, PPV, NPV, LR+ and LR- values were 61%, 77%, 61%, 77%, 2.62 and 0.51, respectively. The area under the ROC curve was 0.689 (P = 0.03). Volume ≤ 1 cm³ at mid-treatment was found significant in a logistic regression (OR: 0.194, P = 0.011). At end-treatment, no ultrasound measurements were found predictive of pCR or pCR/MRD. In conclusion, proportional tumour size changes (the basis of the RECIST criteria) were not found predictive of good pathological response, although residual volume ≤ 1 cm³ at mid-treatment was found to be predictive of pCR/MRD. However, multiple volume and LD thresholds were examined and uncorrected P values presented, increasing the possibility of type I errors. Replication in an independent dataset is required.Breast Cancer Research and Treatment 03/2011; 127(2):459-69. · 4.47 Impact Factor
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ABSTRACT: We have developed a novel parallel-plate diffuse optical tomography (DOT) system for three-dimensional in vivo imaging of human breast tumor based on large optical data sets. Images of oxy-, deoxy-, and total hemoglobin concentration as well as blood oxygen saturation and tissue scattering were reconstructed. Tumor margins were derived using the optical data with guidance from radiology reports and magnetic resonance imaging. Tumor-to-normal ratios of these endogenous physiological parameters and an optical index were computed for 51 biopsy-proven lesions from 47 subjects. Malignant cancers (N=41) showed statistically significant higher total hemoglobin, oxy-hemoglobin concentration, and scattering compared to normal tissue. Furthermore, malignant lesions exhibited a twofold average increase in optical index. The influence of core biopsy on DOT results was also explored; the difference between the malignant group measured before core biopsy and the group measured more than 1 week after core biopsy was not significant. Benign tumors (N=10) did not exhibit statistical significance in the tumor-to-normal ratios of any parameter. Optical index and tumor-to-normal ratios of total hemoglobin, oxy-hemoglobin concentration, and scattering exhibited high area under the receiver operating characteristic curve values from 0.90 to 0.99, suggesting good discriminatory power. The data demonstrate that benign and malignant lesions can be distinguished by quantitative three-dimensional DOT.Journal of Biomedical Optics 01/2009; 14(2):024020. · 2.88 Impact Factor
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ABSTRACT: With the introduction of contrast agents, advances in surface coil technology, and development of new imaging protocols, contrast agent-enhanced magnetic resonance (MR) imaging has emerged as a promising modality for detection, diagnosis, and staging of breast cancer. The reported sensitivity of MR imaging for the visualization of invasive cancer has approached 100%. There are many examples in the literature of MR imaging--demonstrated mammographically, sonographically, and clinically occult breast cancer. Often, breast cancer detected on MR images has resulted in a change in patient care. Despite these results, there are many unresolved issues, including no defined standard technique for contrast-enhanced breast MR imaging, no standard interpretation criteria for evaluating such studies, no consensus on what constitutes clinically important enhancement, and no clearly defined clinical indications for the use of MR imaging. Furthermore, this technology remains costly, and issues of cost-effectiveness and cost competition from percutaneous biopsy have yet to be fully addressed. These factors along with the lack of commercially available MR imaging--guided localization and biopsy systems have slowed the transfer of this imaging technology from research centers to clinical breast imaging practices. Technical requirements, potential clinical applications, and potential pitfalls and limitations of contrast-enhanced MR imaging as a method to help detect, diagnose, and stage breast cancer will be described.Radiology 08/2001; 220(1):13-30. · 6.34 Impact Factor