[Benign metastasizing leiomyoma: An unusual cause of aggressive femoral bone tumor]. / Léiomyome métastatique bénin : une cause inhabituelle de tumeur osseuse fémorale agressive.

BACKGROUND: Benign metastasizing leiomyoma (BML) is a rare condition characterized by histologically benign "metastatic" smooth muscle tumors, which can affect women with history of uterine surgery. We report the case of a patient with bone metastases of BML. CASE REPORT: A 78-year-old woman who had undergone uterine surgery six years before hospital admission, was diagnosed with large pulmonary and pleural metastases that necessitated surgical removal. Pathological examination allowed the diagnosis of BML with positive staining for estrogen and progesterone receptors. Three years later, a BML metastasis in the right femoral diaphysis was unexpectedly discovered and treated by osteosynthesis because of a high risk of fracture. Despite an aromatase-inhibitor treatment, new lungs lesions appeared in the next few months. CONCLUSION: BML is a potential cause of aggressive, although histologically benign, bone tumor in women with a history of uterine surgery.

Dynamic contrast enhanced optical imaging of capillary leakage.

We studied in vivo the vascular permeability of two fluorescent contrast agents in three types of capillary, using a fibered confocal fluorescence microscopy system. Mice were imaged after injection of a macromolecular (albumin FITC 68,000 daltons) or low-molecular-weight contrast agent (FITC 389 daltons). We studied continuous capillaries in muscles (FITC n = 4, albumin FITC n = 6), fenestrated capillaries in mesenteries (FITC n = 8, albumin FITC n = 10), and discontinuous capillaries in xenografted tumors (FITC n = 2, albumin FITC n = 4). Signal intensity (SI) was measured in capillary and interstitial regions, and time-enhancement curves were drawn. Two-compartment models were constructed to determine quantitative microcirculation parameters. The arrival of the bolus of the two different contrast agents was observed in mesentery and muscle capillaries but not in tumor capillaries. Interstitial leakage of the low-molecular-weight contrast agent was observed almost instantaneously, whereas the macromolecular agent remained within the vessels. Signal intensity declined over the observation period, specifically in the tumor. No quantitative microcirculation parameters could be obtained with either of two bi compartmental models, owing to model instability. This study shows that the microcirculation can be reproducibly observed in different types of capillary in vivo with this fibered fluorescence imaging device. Further work is required to quantify microvascular parameters.

In vivo dynamic MRI measurement of the noradrenaline-induced reduction in placental blood flow in mice.

PURPOSE: We developed a new model for in vivo placental perfusion measurements based on dynamic MRI in mice. As noradrenaline has been implicated in the pathogenesis of preeclampsia, we examined whether it reduced placental perfusion in mice, and whether such a reduction could be detected with our MRI model. MATERIALS AND METHODS: Mice at 16 days of gestation were injected intramuscularly with saline or noradrenaline solution. A conventional gadolinium chelate was then injected IV, and a single-slice T1-weighed 2D Fast SPGR sequence was acquired for 200 s. Signal intensity was measured on all the images and converted into contrast agent tissue concentrations in the maternal left ventricle (input function) and placentas. A one-compartment model was developed using compartmental and numerical modeling software. Mean blood flow (F) was calculated from a transfer constant. RESULTS: Twenty-six mice were studied, yielding a total of 55 MRI measurements of placental perfusion (29 in the control group and 26 in the noradrenaline group). Mean placental blood flow (F) was significantly lower in the noradrenaline group (0.72+/-0.84 ml/min/g of placenta) than in the control group (1.26+/-0.54 ml/min/g of placenta). CONCLUSION: Noradrenaline reduces placental perfusion in mice. Our MRI dynamic model might be useful for detecting and investigating abnormal placental blood flow, thereby avoiding the need for invasive procedures and animal sacrifice.

[Placental functional assessment using MRI: mice today, humans tomorrow?]. / L'IRM fonctionnelle pour l'étude de la fonction placentaire: aujourd'hui chez la souris, demain chez l'homme?

Placental insufficiency, a process due to either poor placental perfusion or permeability, may lead to progressive deterioration in placental function and materno-fetal morbidity. Advances in MR contrast media pharmacokinetic studies of transit through tissues and dynamic MRI allow to characterize organs microcirculation in vivo. Placental function assessment might be achieved using analysis of dynamic contrast enhanced MRI of tracers. A murine model of placental assessment has been constructed. Herein, principles, results and limitations of such techniques are discussed as well as their potential interest and weaknesses in humans.