Breast inflammation: indications for MRI and PET-CT.

Breast MRI should not be used for differential diagnosis between inflammatory breast cancer and acute mastitis (AM) prior to treatment. When mastitis symptoms persist after 10 to 15 days of well-managed medical treatment, MRI may be performed in addition to an ultrasound examination, a mammogram and to taking histological samples, in order to eliminate inflammatory breast cancer (IBC). For staging, MRI would seem to be useful in looking for a contralateral lesion, PET-CT for finding information about remote metastases and in certain centres, for information about the initial extension to local/regional lymph nodes, which would guide the fields of irradiation (since patients can become lymph node negative after neoadjuvant chemotherapy). MRI and PET-CT seems to be useful for early detection of patients responding poorly to neoadjuvant chemotherapy so that the latter may be rapidly modified.

[CT-guided percutaneous biopsies]. / Biopsies percutanées sous scanner.

The number of biopsy requests continuously increases over the years. Similarly, lesions that are not amenable to CT-guided biopsy are exceptional due to improved imaging guidance and technical advances. The needle tract should preferably go through fat, which is less painful and safer. The biopsy should be painless with the use of local anesthetics complemented by intravenous sedation. Blunt introducers and hydrodissection techniques create access to lesions without injury to vessels, bowel loops and fascias. The biopsy samples should be processed in accordance with the suspected diagnosis.

[Diffusion-weighted MR imaging of the breast]. / Diffusion en IRM mammaire.

Diffusion-weighted imaging is helpful to further characterize lesions that remain indeterminate after morphological and dynamic MR evaluation. Suspicious lesions are hyperintense on diffusion-weighted images with corresponding low ADC values, indicating restricted diffusion and hypercellularity. Benign lesions and tumors responding to treatment usually have no diffusion restriction. ADC maps are useful for T2W hyperintense lesions that could mask the presence of restricted diffusion. Image fusion is sometimes needed to accurately localize enhancing lesions on ADC maps. For indeterminate lesions, a hypocellular appearance suggests a lower ACR category whereas the presence of restricted diffusion suggests a higher category.

[CT and MRI imaging in tumoral angiogenesis]. / Imagerie TDM et IRM de l'angiogenèse tumorale.

Angiogenesis is the process of activating dormant endothelial cells to form new vessels, after stimulation and it is essential in tumor growth. In many types of cancer, angiogenesis results from the activation of oncogenes that stimulate the production of Vascular Endothelial Growth Factor (VEGF). However, these newly formed vessels have a great number of abnormalities: increased density of fragile and hyper-permeable microvessels, arterial-venous shunts, caliber abnormalities and flow instabilities susceptible to flow direction inversion according to interstitial pressure. Anti-angiogenic treatments inhibit VEGF activity, perceived as structural and functional normalization of the microvascular pattern, such as reduced density of microvessels and restored morphology of the remaining ones. Conventional imaging techniques are not sensible to these changes, at best they show tumor size stabilization, hence the need of new techniques. Microvascularization imaging can be achieved by detecting functional disturbances to blood flow and not by showing the microvasculature per se. These techniques are based in quantifying the enhancement in tumor due to the passage of contrast agent after injection or protons labeled by a magnetic field. Through these measurements, one can derive interstitial and blood volumes as well as the tissue perfusion and capillary wall permeability. Microvascular imaging has greatly benefited from the improvements seen in CT and MRI equipment allowing large volume coverage with high spatial and temporal resolutions as from the evolutions in the methods to calculate, present and compare maps of the microcirculation and it's heterogeneity. However, software to analyze microvascularization are still rare, limiting the technique's application and validation in large scale. Nevertheless, imaging of the microcirculation is useful throughout the care of the oncological patient: it can reinforce the suspicious nature of a lesion, suggest anti-angiogenic treatment efficacy in hypervascular lesions, and show early treatment response before morphological changes as in RECIST criteria.

[Evaluation of a fully integrated digital screening mammography program in the Vienne region]. / Evaluation du tout numérique dans le dépistage organisé du cancer du sein à travers une expérience dans le département de la Vienne.

PURPOSE: To evaluate a fully integrated digital screening mammography program (image acquisition, transfer and over-read). MATERIALS AND METHODS: between april 2005 and December 2007, two imaging sites were authorized by the Department of Health to use digital mammography units (Senographe 2000D and 2000DS, GEMS) for screening mammography. the initial interpretation was made on a workstation with accompanying digital films. The images were also transmitted via the internet on the same day for over-read on a workstation. In addition, a <> over-read was also performed from printed mammographic images using a viewbox. Differences in interpretation and BIRADS classification as well as economical considerations were analyzed between the types of interpretation setups. RESULTS: A total of 7008 screening mammograms were included. No significant problem was reported with regards to internet image transfers. No significant interpretation difference was noted related to the fully integrated digital imaging process. This technology could generate cost savings estimated in 2007 at 3.793/year (mailing fee). CONCLUSION: A fully integrated digital screening mammography program results in improved organisational processes and significant cost reductions without reduced diagnostic accuracy.