M Douek

Three-dimensional time-resolved optical mammography of the uncompressed breast

Optical tomography is being developed as a means of detecting and specifying disease in the adult female breast. We present a series of clinical three-dimensional optical images obtained with a 32-channel time-resolved system and a liquid-coupled interface. Patients place their breasts in a hemispherical cup to which sources and detectors are coupled, and the remaining space is filled with a highly scattering fluid. A cohort of 38 patients has been scanned, with a variety of benign and malignant lesions. Images show that hypervascularization associated with tumors provides very high contrast due to increased absorption by hemoglobin. Only half of the fibroadenomas scanned could be observed, but of those that could be detected, all but one revealed an apparent increase in blood volume and a decrease in scatter and oxygen saturation.

Does breast cancer exist in a state of chaos

INTRODUCTIONÐMODELS OF DISEASE Throughout the history of medicine mankind has demonstrated extraordinary feats of imagination in elaborating hypothetical models to explain the nature of disease. These models then suggest therapeutic strategies to influence the natural history of disease processes. Until the early 17th Century in Western medicine and to this day in classical Chinese medicine these models were largely metaphysical [1]. However, Ayurveda, the Indian system of medicine, is based on a dynamic balance between three principles: combustion/ energy-production/anabolism (Pitta), transport/communication (Vaata), and excretion/catabolism (Kapha). Disease was supposed to be a manifestation of the disturbance of this balance and the doctors duty was to maintain and restore this balance [2]. In the last century or so models of disease have progressed from the mechanical to the biological and more recently to the mathematical. The change of allegiance from one model to another has been likened to a Kuhnian revolution or paradigm shift [3]. The two most famous in the history of medicine were the overthrowing of the Gallenic doctrine by William Harveys description of the circulation of the blood and the replacement of the miasma theory of infection by the bacterial theory of infection which ultimately led to the success of anti-microbial therapy.

Can magnetic-resonance imaging help elucidate natural history of breast cancer multicentricity?

We evaluated prospectivelywhether small enhancing foci, seen separately from the maintumour on contrast-enhanced MRI, were indeed cancer fociand whether MRI could detect all cancer foci identified byradiological-histological correlation.We studied ten patients and did preoperative contrast-enhanced breast MRI. High resolution transverse T1-weighted 3D FLASH images (TR=18 ms, TE=7 ms,FA=40°, TA=4 m 56 s, FOV=410 mm) before and after anintravenous bolus hand injection of dimegluminegadopentetate (Magnevist, 0·2 mL/kg) were acquired at 1·0T (Siemens Magnetom Scanner 42 SP with dedicated breastcoil). The 3D volume was 64 mm thick with 32 partitionsgiving an effective slice thickness of 2 mm and this wassufficient to cover the entire breast in all cases. After surgicalexcision (four mastectomies, six wide local excisions), thespecimens were fixed and sliced at 5 mm intervals in thesame plane as the MRI. Routine histopathologicalexamination was performed by an experienced breastpathologist and the remaining material was radiographed.Two observers identified radiological abnormalities(calcifications, densities, or spiculations) and all lesions thatwere deemed suspicious by either observer were sampledand examined histologically. MRI images were reviewedindependently and findings were compared withhistopathology results.On MRI, 19 enhancing foci separate from the maintumour were identified in seven out of ten patients (figure).On radiography of specimen slices, 71 suspicious areas weresampled and histological examination revealed 15 areas ofin-situ cancer (nine) or invasive cancer (six) in five patients.All five patients with cancer foci were amongst the sevenpatients who had enhancing foci on MRI. In two of these fivepatients, the tumour was surrounded by widespreadenhancement on MRI and all 11 (four+seven) areas sampledshowed cancer foci. In all wide local excision specimens, theenhancing foci on MRI were within 11 mm of the tumouredge and therefore within the resected specimen.Our data suggest that enhancing foci on MRI representcancer foci and that MRI detected 14 out of 15 cancer foci(sensitivity 93%). Of course, this is based on the assumptionthat the radiological-histological correlational method isindeed the gold standard. If that is so, the specificity of MRIfor tumour detection would be 79% (15/19). However,bearing in mind that the spatial resolution of MRI is of theorder of 1–2 mm, it may yet transpire that MRI could haveeven greater sensitivity and specificity which may becomeapparent with an even more obsessional sampling of thespecimen.

Anisotropic behaviour of breast tissue for large compressions

Several methods have been proposed to simulate large breast compressions such as those occurring during X-ray mammography. However evaluation of these methods against real data is rare. We acquired magnetic resonance images of eleven breasts before and after applying a relatively large in-vivo compression in the medial direction. Using non-rigid registration we observed an anisotropic deformation behaviour, with a reduced elongation in the anterior-posterior direction and an increased stretch in inferior-superior direction for all but one subject. Higher anisotropy was observed for larger compressions and in the central breast region. Using finite element simulations, we assessed the optimum performance of isotropic and transverse isotropic material models to predict the displacement of internal landmarks. We found that isotropic materials reduced the mean displacement error from 23.3mm to 4.3mm on average. Smaller errors were achieved with transverse isotropic materials (3.8mm). For large compressions (≫35%) the difference (5.2mm vs. 4.1mm) was statistically significant (p=0.04). Of the parameters varied, the amount of skin stiffness and anisotropy had the greatest influence on the results.

Good practice and quality assurance in surgical oncology

The Halstedian era of radical surgical extirpation for solid tumours dominated the first half of the 20th century. But as understanding of cancer biology increased, a paradigm shift occurred which moved the focus away from extensive surgery towards less radical procedures. Although surgery is a recognised factor in local disease control, prognosis is now believed to be predetermined at the time of diagnosis by the presence of micrometastatic deposits. Modern cancer management consists of more skilled and conservative surgery to remove the primary tumour; adjuvant therapies are also given before and after the operation to target the subclinical metastatic deposits. The most important components of high-quality care in surgical oncology are: sound clinical judgment, surgical skill, and multidisciplinary care. These prerequisites are best achieved by specialisation, but high operative volume is not essential for excision of many types of tumour. Quality assurance using several readily available tools can ensure that the process of care from presentation to outcome is constantly improved and that institutional variations in number of cases and quality of care are monitored.

Does preoperative MRI influence the extent of surgical resection in conservative breast cancer surgery

Abstract We assessed prospectively the impact of preoperative breast magnetic resonance (MRI) on the extent of surgical resection. Of 131 breast cancers treated with breast conservation over 18 months, 41 underwent preoperative MRI. Scans were shown to the operating surgeon to indicate the location of lesions and their local extent. Clinical information and histological assessment of wide local excision specimens were compared between those patients who underwent preoperative MRI and those who did not. There was no significant difference between the MRI group ( n =41) and no-MRI group ( n =90) in average specimen weight ( P = 0.72) or circumferential margin status ( P = 0.17). Logistic regression analysis demonstrated a positive correlation between margin status and patient age ( P = 0.045), younger patients being more likely to have involved margins, and a negative correlation with MRI status ( P = 0.006) these women having an MRI being more likely to have negative margins. Preoperative MRI does not currently influence the extent of surgical resection in breast conservation surgery.