Magnetic resonance imaging of breast lesions - A pathologic correlation
ABSTRACT Magnetic resonance imaging of the breast is useful in assessing breast lesions. An understanding of the pathologic characteristics of the tumors may help to understand these magnetic resonance imaging observations.Large lesional size (>10 mm), ill-defined margin, and irregular outlines are associated with malignancy. These correlate with the pathological features of breast tumor, characterized by rapid growth rate, large size, and infiltrative growth pattern, invasion into stroma resulting in desmoplasia, and hence irregular outline and margin. The detection and estimation of tumor extent of invasive lobular carcinoma is problematic, even with magnetic resonance imaging, which is considered the most sensitivity. This inaccuracy likely derives from the characteristic linear, single cells infiltration growth pattern of the tumor, which is also often underestimated by clinical examination. Estimation of tumor extent after neoadjuvant chemotherapy is also essential but problematic by imaging, as the shrunken tumor becomes fibrotic, with stromal hyalinization, diminished microvasculature and tumor break up causing size underestimation. Non-enhancement of breast tumors occurs in about 8% of cases correlates with diffuse growth pattern, particularly of infiltrative lobular carcinoma. The observation of disproportionately high non-enhancing ductal carcinoma in situ remains an enigma. Finally, early rim enhancement correlates with small cancer nests, low ratio of peripheral to central fibrosis and high ratio of peripheral to central microvessel density. These may be related to increased vascular endothelial growth factor mediated increased microvessel density as well as increased permeability, which manifest as increased rapid contrast uptake and dissipation.
- SourceAvailable from: Marc Lobbes
Imaging of the Breast - Technical Aspects and Clinical Implication, 03/2012; , ISBN: 978-953-51-0284-7
- "For nonmass-like enhancement, features that have the highest positive predicitive value are clumped linear, segmental or regional enhancement. Lesions larger than 10 mm have a higher positive predictive value for being malignant than lesions < 10 mm (Tse et al., 2007). "
Conference Paper: Speaker-independent isolated word recognition using a one-pass analysis[Show abstract] [Hide abstract]
ABSTRACT: The system described in this paper is an outgrowth of one described in  and is a combination of deterministic and probabilistic speech recognition strategies. It is intended for telephone quality speech and possible single chip implementation with memory requirements of 256 bytes for processing (RAM) and 8k bytes for template storage and programs (ROM). Two major modifications for effecting reduction in memory requirements are described. The first is the use of a one-pass analysis algorithm for processing an utterance. The second is an approach for generation of uniform segment prototypes. Modification of the original system for telephone quality speech included obvious changes in filter bank analysis and parameterization of each phonetically classified segment with more emphasis on the voiced portions of utterances. The system was evaluated on a ten digit vocabulary (21 talkers, over 1000 tokens) and showed an accuracy of 94.4% with a 3.1% error rate and 2.5% rejection rate.Acoustics, Speech, and Signal Processing, IEEE International Conference on ICASSP '84.; 04/1984
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ABSTRACT: Neoadjuvant chemotherapy for breast cancer reduces tumour cellularity, the percentage of the primary tumour area that is composed of invasive tumour cells. Minimal residual tumour cellularity (5 per cent or less of tumour area composed of invasive tumour cells) may be associated with an increased risk of false-negative intraoperative margins. The aim of this study was to evaluate the incidence of minimal residual tumour cellularity after neoadjuvant chemotherapy and its impact on the frequency of false-negative margins and conversion from breast-conserving surgery to mastectomy. The final pathology slides of 510 patients who had surgery after neoadjuvant chemotherapy were reviewed. Of 396 patients with residual invasive breast cancer after neoadjuvant chemotherapy, 100 specimens (25.3 per cent) had minimal residual cellularity; this was more frequent in patients with invasive lobular carcinoma (17.0 versus 5.1 per cent; P < 0.001) or well and moderately differentiated carcinoma (68.0 versus 52.4 per cent; P = 0.007). Among 149 patients who had initial breast-conserving surgery, false-negative intraoperative margin rates were 23 per cent in specimens with minimal and 13.8 per cent in those with higher residual cellularity (P = 0.210). There was no significant difference in the rate of conversion to mastectomy between the groups. Minimal residual cellularity after neoadjuvant chemotherapy occurred in about 25 per cent of specimens, but did not alter the rate of false-negative intraoperative margins.British Journal of Surgery 04/2007; 95(4):433-7. DOI:10.1002/bjs.6044 · 5.21 Impact Factor