Enhanced diffuse optical tomographic reconstruction using concurrent ultrasound information.

Multimodal imaging is an active branch of research as it has the potential to improve common medical imaging techniques. Diffuse optical tomography (DOT) is an example of a low resolution, functional imaging modality that typically has very low resolution due to the ill-posedness of its underlying inverse problem. Combining the functional information of DOT with a high resolution structural imaging modality has been studied widely. In particular, the combination of DOT with ultrasound (US) could serve as a useful tool for clinicians for the formulation of accurate diagnosis of breast lesions. In this paper, we propose a novel method for US-guided DOT reconstruction using a portable time-domain measurement system. B-mode US imaging is used to retrieve morphological information on the probed tissues by means of a semi-automatical segmentation procedure based on active contour fitting. A two-dimensional to three-dimensional extrapolation procedure, based on the concept of distance transform, is then applied to generate a three-dimensional edge-weighting prior for the regularization of DOT. The reconstruction procedure has been tested on experimental data obtained on specifically designed dual-modality silicon phantoms. Results show a substantial quantification improvement upon the application of the implemented technique. This article is part of the theme issue 'Synergistic tomographic image reconstruction: part 2'.

Order-Disorder Structural Transitions in Mazes Built by Evaporating Drops.

We show that the evaporation of surfactant solutions confined in quasi-two-dimensional porous media creates micron-sized labyrinthine patterns composing the walls of a centimeter-sized maze. These walls are made of solid deposits formed during drying via a sequence of individual Haines jumps occurring at the pore scale. We rationalize this process driven by simple iterative rules with a cellular automaton that acts as a maze generator. This model well describes the formation dynamics and final structure of an experimental maze as functions of the wettability heterogeneities of a porous medium and its geometry. Also, our findings unveil the crucial role of two geometric dimensionless quantities that control the structural order of a maze.

Non-palpable breast lesions localization techniques - A new priority: Results of a Senonetwork survey among breast centers in Italy.

INTRODUCTION: Non palpable breast tumors are increasingly diagnosed because of screening programs, and their localization during surgery is essential to ensure an adequate resection. Little is known regarding which techniques are used in "real world". MATERIALS AND METHODS: A national web-based survey, with a 21-items questionnaire, was conducted among Breast Centers (BCs) in Italy in 2023. RESULTS: Among 153 BCs, 110 (72 %) participated. Wire-guided localization was reported to be the most used technique, regardless of the volume of malignant tumors treated by each Center (N = 36, 33 %). However, newer techniques such as Radioactive occult lesion localization and magnetic seeds, were reported to be employed in 34 (31 %) BCs, and more often among high-volume BCs (>300 cases/year) (N = 32, 29 % vs. N = 13, 12 %; p = 0.02). Logistic problems of localization were reported to cause delays to the scheduled surgery at least once or in multiple occasions in 26 (24 %) and in 4 (3.5 %) BCs, respectively. Although the majority of BCs declared they were satisfied (N = 48, 44 %) or somewhat satisfied (N = 41, 37 %) with the procedure used in their center, responders stated that they would change their technique, or that they were strongly considering this possibility in 24 (22 %) and in 38 (35 %) cases, respectively. The main barrier to introducing a new technique was associated with procedure costs (90 BCs, 82 %). CONCLUSIONS: There are several critical issues regarding localization techniques at a national level. This should be recognized as a priority because of its impact on both patients and clinical practices.

Acidic lipase Lip I.3 from a Pseudomonas fluorescens-like strain displays unusual properties and shows activity on secondary alcohols.

AIMS: Identification, cloning, expression and characterization of a novel lipase--Lip I.3--from strain Pseudomonas CR-611. METHODS AND RESULTS: The corresponding gene was identified and isolated by PCR-amplification, cloned and expressed in Escherichia coli, and purified by refolding from inclusion bodies. Analysis of the deduced amino acid sequence revealed high homology with members of the bacterial lipase family I.3, showing 97% identity to a putative lipase from Pseudomonas fluorescens Pf0-1, and 93% identity to a crystallized extracellular lipase from Pseudomonas sp. MIS38. A typical C-terminal type I secretion signal and several putative Ca(2+) binding sites were also identified. Experimental data confirmed that Lip I.3 requires Ca(2+) ions for correct folding and activity. The enzyme differs from the previously reported family I.3 lipases in optimal pH, being the first acidophilic lipase reported in this family. Furthermore, Lip I.3 shows a strong preference for medium chain fatty acid esters and does not display interfacial activation. When tested for activity on secondary alcohol hydrolysis, Lip I.3 displayed higher efficiency on aromatic alcohols rather than on alkyl alcohols. CONCLUSIONS: A new family I.3 lipase with unusual properties has been isolated, cloned and described. This will contribute to a better knowledge of family I.3 lipases, a family that has been scarcely explored, and that might provide a novel source of biocatalysts. SIGNIFICANCE AND IMPACT OF THE STUDY: The unusual properties shown by Lip I.3 and the finding of activity and enantioselectivity on secondary alcohol esters may contribute to the development of new enzymatic tools for applied biocatalysis.

Nonpalpable breast lesions: preoperative radiological guidance in radioguided occult lesion localisation (ROLL).

PURPOSE: This study evaluated the methods, technical aspects and impact of preoperative radiological guidance in radioguided occult lesion localisation (ROLL) for single nonpalpable breast lesions. MATERIALS AND METHODS: A total of 288 patients underwent ROLL before surgery. Human serum albumin macroaggregates labelled with 3.7-7.4 MBq of technetium(99) were injected into the lesion. In the case of ultrasonographic guidance (221/288 patients), inoculum positioning resulted in a change of echogenicity at the lesion site. In the case of mammographic guidance (67/288 patients), iodinated contrast medium was injected following the radiotracer for subsequent mammographic evaluation. Patients underwent surgery within 24 h from ROLL. A gamma-detecting probe was used to locate the lesion during surgery and guide its removal. After excision, the specimen was examined by either ultrasonography or mammography to verify complete lesion removal before histological evaluation. RESULTS: The lesion was correctly localised in 281/288 patients (97.5%). One ROLL procedure failed because surgery could not be performed within 24 h and the radioactivity decayed. Of the six incorrect localisations, 2 were due to the radiological guidance and 4 to technetium(99) dispersion. CONCLUSIONS: Radiological guidance in ROLL ensured the outcome of the procedure of localisation and removal of single, nonpalpable breast lesions in the majority of cases.

Complex dynamics of droplet traffic in a bifurcating microfluidic channel: periodicity, multistability, and selection rules.

The binary path selection of droplets reaching a T junction is regulated by time-delayed feedback and nonlinear couplings. Such mechanisms result in complex dynamics of droplet partitioning: numerous discrete bifurcations between periodic regimes are observed. We introduce a model based on an approximation that makes this problem tractable. This allows us to derive analytical formulae that predict the occurrence of the bifurcations between consecutive regimes, establish selection rules for the period of a regime, and describe the evolutions of the period and complexity of droplet pattern in a cycle with the key parameters of the system. We discuss the validity and limitations of our model which describes semiquantitatively both numerical simulations and microfluidic experiments.

"CADEAT": considerations on the use of CAD (computer-aided diagnosis) in mammography.

Computer-aided diagnosis (CAD) has been extensively reported to increase sensitivity by about 10% when added to a single reading while increasing recall rate by 12%, and its current use can be safely recommended in clinical practice. CAD has been suggested as a possible alternative to conventional double reading in screening. Uncontrolled comparison is consistent and suggests that CAD is comparable to double reading in incremental cancer detection rate (CAD +10.6%, double reading +9.1%) and possibly better in recall rate (CAD +12.5%, double reading +28.8%). However, controlled studies comparing single reading + CAD to conventional double reading are not consistent and on average suggest a lower cancer detection rate (-5.1%) and a lower recall rate (-9.8%) for CAD. Scientific evidence is not sufficient for a safe recommendation of single reading + CAD as a current alternative to conventional double reading.

Droplet motion in microfluidic networks: Hydrodynamic interactions and pressure-drop measurements.

We present experimental, numerical, and theoretical studies of droplet flows in hydrodynamic networks. Using both millifluidic and microfluidic devices, we study the partitioning of monodisperse droplets in an asymmetric loop. In both cases, we show that droplet traffic results from the hydrodynamic feedback due to the presence of droplets in the outlet channels. We develop a recently-introduced phenomenological model [W. Engl, Phys. Rev. Lett. 95, 208304 (2005)] and successfully confront its predictions to our experimental results. This approach offers a simple way to measure the excess hydrodynamic resistance of a channel filled with droplets. We discuss the traffic behavior and the variations in the corresponding hydrodynamic resistance length L_{d} and of the droplet mobility beta , as a function of droplet interdistance and confinement for channels having circular or rectangular cross sections.

Prediction of Chemoresistance in Women Undergoing Neo-Adjuvant Chemotherapy for Locally Advanced Breast Cancer: Volumetric Analysis of First-Order Textural Features Extracted from Multiparametric MRI.

Purpose: To assess correlations between volumetric first-order texture parameters on baseline MRI and pathological response after neoadjuvant chemotherapy (NAC) for locally advanced breast cancer (BC). Materials and Methods: 69 patients with locally advanced BC candidate to neoadjuvant chemotherapy underwent MRI within 4 weeks from the start of therapeutic regimen. T2, DWI, and DCE sequences were analyzed and maps were generated for Apparent Diffusion Coefficient (ADC), T2 signal intensity, and the following dynamic parameters: k-trans, peak enhancement, area under curve (AUC), time to maximal enhancement (TME), wash-in rate, and washout rate. Volumetric analysis of these parameters was performed, yielding a histogram analysis including first-order texture kinetics (percentiles, maximum value, minimum value, range, standard deviation, mean, median, mode, skewness, and kurtosis). Finally, correlations between these values and response to NAC (evaluated on the surgical specimen according to RECIST 1.1 criteria) were assessed. Results: Out of 69 tumors, 33 (47.8%) achieved complete pathological response, 26 (37.7%) partial response, and 10 (14.5%) no response. Higher levels of AUCmax (p value = 0.0338), AUCrange (p value = 0.0311), and TME75 (p value = 0.0452) and lower levels of washout10 (p value = 0.0417), washout20 (p value = 0.0138), washout25 (p value = 0.0114), and washout30 (p value = 0.05) were predictive of noncomplete response. Conclusion: Histogram-derived texture analysis of MRI images allows finding quantitative parameters predictive of nonresponse to NAC in women affected by locally advanced BC.

Slow relaxation mode in concentrated oil-in-water microemulsions consisting of repulsive droplets.

The present contribution reports on the observation of two diffusive relaxation modes in a concentrated microemulsion made of repulsive droplets. These two modes can be interpreted in the frame of Weissman's and Pusey's theoretical pioneering works. The fast mode is associated to the collective diffusion of droplets whereas the slow one corresponds to the relaxation of droplet concentration fluctuations associated with composition and/or size. We show that (i) repulsive interactions considerably slow down the latter and (ii) a generalized Stokes Einstein relationship between its coefficient of diffusion and the Newtonian viscosity of the solutions, similar to the Walden's rule for electrolytes, holds for concentrated microemulsion systems made of repulsive droplets.

Study and formation of vesicle systems with low polydispersity index by ultrasound method.

The formation of liposomes with low polydispersity index by application of ultrasounds was investigated considering methodology specifications such as sonication time and sonication power. Phosphatidylcholine (PC) liposomes were formed by the evaporation-hydration method. The vesicles were sonicated using several sonication conditions. The liposomes were then characterized by dynamic light scattering (DLS) and freeze-fracture electron microscopy (FFEM). Correlation functions from DLS were treated by cumulants method and GENDIST to obtain the mean radius and polydispersity index. These calculations allowed to fix an optimal sonication time (3000 s) and a useful interval of ultrasound power between 39 and 91 W. DLS and FFEM results confirmed that vesicle size, lamellarity and the polydispersity index decreased with the increase of sonication power. Thus, we propose a systematic method to form liposomes in which the physical characteristics of the vesicles may be controlled as a function of sonication time and power.

Structural steady states and relaxation oscillations in a two-phase fluid under shear flow: experiments and phenomenological model.

By means of several rheophysics techniques, we report on an extensive study of the couplings between flow and microstructures in a two-phase fluid made of lamellar (L(alpha)) and sponge (L(3)) phases. Depending on the nature of the imposed dynamical parameter (stress or shear rate) and on the experimental conditions (brine salinity or temperature), we observe several different structural steady states consisting of either multilamellar droplets (with or without a long range order) or elongated (L(3)) phase domains. Two different astonishing phenomena, shear-induced phase inversion and relaxation oscillations, are observed. We show that (i) phase inversion is related to a shear-induced topological change between monodisperse multilamellar droplets and elongated structures and (ii) droplet size relaxation oscillations result from a shear-induced change of the surface tension between both coexisting (L(alpha)) and (L(3)) phases. To explain these relaxation oscillations, we present a phenomenological model and compare its numerical predictions to our experimental results.

Formation and properties of mini-emulsions formed by microemulsions dilution.

Mini-emulsions have been formed in quaternary systems water/hexanol/sodium dodecyl sulfate/decane by dilution of a microemulsion with an excess of water. We have investigated systematically the effect of composition variables in the droplet size and Ostwald Ripening rate. This droplet size has been investigated by using dynamic light scattering of samples submitted to further dilution in water. According to the dynamic light scattering results, the initial droplet size depends on the initial microemulsion water content, the larger the initial water concentration, the smaller the initial droplet size. This is probably related to the structure of the initial phase. The rate of Ostwald Ripening depends on the final surfactant concentration as expected for differences in interfacial tension. At high surfactant and dispersed phase contents, instability due to flocculation has been observed. Other experiments in which a fifth component (a more hydrophobic oil) was added to slow down Ostwald Ripening showed an initial droplet size increasing comparable to the systems without additive but after a relatively long time of approximately 2 h, a decrease was observed.

MR state of the art.

Magnetic resonance imaging is undergoing continual and progressive evolution. To make a high quality examination, some requirements are mandatory, such as high spatial and contrast resolution to identify lesions and high temporal resolution to characterize them. We review the most important new magnetic resonance technologies, both those which are already available and used in clinical practice and those which are still to be developed. We analyze such technologic and methodolgic features as magnetic field strength, gradients, surface coils, echoplanar imaging, fat suppression techniques and magnetization transfer, contrast agents, automatic injectors, image postprocessing, computer assisted diagnosis, magnetic resonance-guided biopsy and spectroscopy. All these factors are in continuous evolution and new technologies anticipate, in the near future, faster examinations with very high spatial and contrast resolution, with magnetic resonance-guided cytologic and histologic aspiration biopsies, as well as spectroscopic studies of previously identified lesions. To perform a correct, state-of-the-art magnetic resonance examination of the breast, we need high strength gradients with high slew rate and bilateral coils. Finally, we discuss new technologies and methods which will increase the accuracy of magnetic resonance studies of the breast, improving image quality and decreasing execution time. Thus, magnetic resonance spectroscopy, allowing in vivo biochemical tissue analysis, seems to have high potentials; even though they are still difficult to define, the technique is sure to have major diagnostic impact also in monitoring the results to different treatments.

Shear-induced formation of vesicles in membrane phases: kinetics and size selection mechanisms, elasticity versus surface tension.

Multilamellar vesicles can be formed upon shearing lamellar phases (L(alpha)) and phase-separated lamellar-sponge (L(alpha)/L(3)) mixtures. In the first case, the vesicle volume fraction is always 100% and the vesicle size is monitored by elasticity ("onion textures"). In the second system the vesicle volume fraction can be tuned from 0 to 100% and the mean size results from a balance between capillary and viscous forces ("Taylor droplets"). However, despite these differences, in both systems we show that the formation of vesicles is a strain-controlled process monitored by a universal primary buckling instability of the lamellae.

Can a droplet break up under flow without elongating? Fragmentation of smectic monodisperse droplets.

We study the fragmentation under shear flow of smectic monodisperse droplets at high volume fraction. Using small angle light scattering and optical microscopy, we reveal the existence of a break-up mechanism for which the droplets burst into daughter droplets of the same size. Surprisingly, this fragmentation process, which is strain controlled and occurs homogeneously in the cell, does not require any transient elongation of the droplets. Systematic experiments as a function of the initial droplet size and the applied shear rate show that the rupture is triggered by an instability of the inner droplet structure.

Conductivity of an inverse lyotropic lamellar phase under shear flow.

We report conductivity measurements on solutions of closed compact monodisperse multilamellar vesicles (the so-called "onion texture") formed by shearing an inverse lyotropic lamellar L(alpha) phase. The conductivity measured in different directions as a function of the applied shear rate reveals a small anisotropy of the onion structure due to the existence of free oriented membranes. The results are analyzed in terms of a simple model that allows one to deduce the conductivity tensor of the L(alpha) phase itself and the proportion of free oriented membranes. The variation of these two parameters is measured along a dilution line and discussed. The high value of the conductivity perpendicular to the layers with respect to that of solvent suggests the existence of a mechanism of ionic transport through the insulating solvent.

Ribbon phase in a phase-separated lyotropic lamellar-sponge mixture under shear flow.

We report the effect of shear flow on a phase-separated system composed of lyotropic lamellar (L(alpha)) and sponge (L3) phases in a mixture of brine, surfactant, and cosurfactant. Optical microscopy, small-angle light, and x-ray scattering measurements are consistent with the existence of a steady state made of multilamellar ribbon-like structures aligned in the flow direction. At high shear rates, these ribbon-like structures become unstable and break up into monodisperse droplets resulting in a shear-thickening transition.

Usefulness of breast MRI in a patient with genetic risk.

We describe an interesting case-report represented by a patient carrying BRCA1 mutation, recruited for the study "Multicenter evaluation of Magnetic Resonance Imaging (MRI) in early diagnosis and prevention of breast cancer in high risk population", diagnosed with breast cancer on the basis of MRI findings but not with conventional mammography and ultrasound (US). She was already affected at 53 years of age by a multifocal Ductal Infiltrating Carcinoma (DIC) in the left breast; then, she had an axillary and sovraclavear nodal recurrence of the disease, three years after the initial diagnosis. Since other relatives were affected by breast cancer (mother, sister and niece) and two arose at early age (< 40 years), BRCA1 mutational analysis was offered to the patient, identifying a nonsense mutation on the exon 13. Furthermore, this patient was recruited to study contralateral breast and at the second round, two little foci, suspicious of malignancy, were identified only with MRI, but not with mammography and ultrasonography. The final diagnosis was multifocal Ductal Carcinoma in situ (DCIS); the major focus measured 3 mm. In our patient MRI has shown a major sensitivity with respect to conventional radiology and US and has provided a very early diagnosis in this woman at genetic risk.

[Intermittent chronic occlusion of the duodenum caused by pheochromocytoma]. / Occlusione cronica intermittente del duodeno da feocromocitoma.

A case (63 y. old male) of intermittent duodenal obstruction is presented. Aortographic investigation showed a neoplastic mass in the right adrenal gland. At laparotomy the mass, histologically diagnosed as a pheochromocytoma, appeared to infiltrate the duodenal wall, displacing it upward. Though gastrointestinal disturbances have been frequently recorded in pheochromocytoma, as far as we know this is the first description of intermittent duodenal obstruction in this disease.