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.

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.

Path selection rules for droplet trains in single-lane microfluidic networks

We investigate the transport of periodic trains of droplets through microfluidic networks having one inlet, one outlet, and nodes consisting of T junctions. Variations of the dilution of the trains, i.e., the distance between drops, reveal the existence of various hydrodynamic regimes characterized by the number of preferential paths taken by the drops. As the dilution increases, this number continuously decreases until only one path remains explored. Building on a continuous approach used to treat droplet traffic through a single asymmetric loop, we determine selection rules for the paths taken by the drops and we predict the variations of the fraction of droplets taking these paths with the parameters at play including the dilution. Our results show that as dilution decreases, the paths are selected according to the ascending order of their hydrodynamic resistance in the absence of droplets. The dynamics of these systems controlled by time-delayed feedback is complex: We observe a succession of periodic regimes separated by a wealth of bifurcations as the dilution is varied. In contrast to droplet traffic in single asymmetric loops, the dynamical behavior in networks of loops is sensitive to initial conditions because of extra degrees of freedom.

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.

Towards high throughput production of artificial egg oocytes using microfluidics

The production of micron-size droplets using microfluidic tools offers new opportunities to carry out biological assays in a controlled environment. We apply these strategies by using a flow-focusing microfluidic device to encapsulate Xenopus egg extracts, a biological system recapitulating key events of eukaryotic cell functions in vitro. We present a method to generate monodisperse egg extract-in-oil droplets and use high-speed imaging to characterize the droplet pinch-off dynamics leading to the production of trains of droplets. We use fluorescence microscopy to show that our method does not affect the biological activity of the encapsulated egg extract by observing the self-organization of microtubules and actin filaments, two main biopolymers of the cell cytoskeleton, encapsulated in the produced droplets. We anticipate that this assay might be useful for quantitative studies of biological systems in a confined environment as well as high throughput screenings for drug discovery.

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.

Competition between local collisions and collective hydrodynamic feedback controls traffic flows in microfluidic networks

By studying the repartition of monodisperse droplets at a simple T junction, we show that the traffic of discrete fluid systems in microfluidic networks results from two competing mechanisms, whose significance is driven by confinement. Traffic is dominated by collisions occurring at the junction for small droplets and by collective hydrodynamic feedback for large ones. For each mechanism, we present simple models in terms of the pertinent dimensionless parameters of the problem.

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.

Selection of two-phase flow patterns at a simple junction in microfluidic devices

We study the behavior of a confined stream made of two immiscible fluids when it reaches a T junction. Two flow patterns are witnessed: the stream is either directed in only one sidearm, yielding a preferential flow pathway for the dispersed phase, or splits between both. We show that the selection of these patterns is not triggered by the shape of the junction nor by capillary effects, but results from confinement. It can be anticipated in terms of the hydrodynamic properties of the flow. A simple model yielding universal behavior in terms of the relevant adimensional parameters of the problem is presented and discussed.

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.

Smart control of monodisperse Stöber silica particles: effect of reactant addition rate on growth process

Control over the synthesis of monodisperse silica particles up to mesoscopic scale is generally made difficult due to intrinsic limitation to submicrometric dimensions and secondary nucleation in seeded experiments. To investigate this issue and overcome these difficulties, we have implemented single step processing by quantifying the effects of the progressive addition of a diluted tetraethyl orthosilicate solution in ethanol on the size and monodispersity of silica particles. Contrary to particles grown in seeded polymerization, monodisperse particles with size up to 2 microm were synthesized. Moreover, the particles exhibit a final diameter (d(f)), which varies with V(-1/3) over more than 2 orders of magnitude in rate of addition (V). On the basis of a kinetic study in the presence of addition showing that particle growth is limited by the diffusion of monomer species, we developed a diffusion-limited growth model to theoretically explain the observed d(f)(V) behavior and quantitatively retrieve the measured amplitude and exponent. Using a single parameter procedure, we can therefore predict and generate in the room temperature range, monodisperse particles of a targeted size by simply adjusting the rate of addition.

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.

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.

Formation and properties of miniemulsions 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.

Instability of a lamellar phase under shear flow: formation of multilamellar vesicles

The formation of closed-compact multilamellar vesicles (referred to in the literature as the "onion texture") obtained upon shearing lamellar phases is studied using small-angle light scattering and cross-polarized microscopy. By varying the shear rate gamma;, the gap cell D, and the smectic distance d, we show that: (i) the formation of this structure occurs homogeneously in the cell at a well-defined wave vector q(i), via a strain-controlled process, and (ii) the value of q(i) varies as (dgamma;/D)(1/3). These results strongly suggest that formation of multilamellar vesicles may be monitored by an undulation (buckling) instability of the membranes, as expected from theory.

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.

The Italian multi-centre project on evaluation of MRI and other imaging modalities in early detection of breast cancer in subjects at high genetic risk

This report presents the preliminary results of the first phase (21 months) of a multi-centre, non-randomised, prospective study, aimed at evaluating the effectiveness of contrast-enhanced magnetic resonance imaging (MRI), X-ray mammography (XM) and ultrasound (US) in early diagnosis of breast cancer (BC) in subjects at high genetic risk. This Italian national trial (coordinated by the Istituto Superiore di Sanità, Rome) so far recruited 105 women (mean age 46.0 years; median age 51.0; age range 25-77 years), who were either proven BRCA1 or BRCA2 mutation carriers or had a 1 in 2 probability of being carriers (40/105 with a previous personal history of BC). Eight cases of breast carcinomas were detected in the trial (mean age 55.3 years, median age 52.5; age range 35-70 years; five with previous personal history of BC). All trial-detected BC cases (8/8) were identified by MRI, while XM and US correctly classified only one. MRI had one false positive case, XM and US none. Seven "MRI-only" detected cancers (4 invasive, 3 in situ) occurred in both pre- (n = 2) and post-menopausal (n = 5) women. With respect to the current XM screening programmes addressed to women in the age range 50-69 years, the global incidence of BC in the trial (7.6%) was over ten-fold higher. The cost per "MRI-only" detected cancer in this particular category of subjects at high genetic risk was substantially lower than that of an XM-detected cancer in the general women population. These preliminary results confirmed that MRI is a very useful tool to screen subjects at high genetic risk for breast carcinoma, not only in pre-, but also in post-menopausal age, with a low probability of false positive cases.

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.

[The current state of the diagnostics of breast diseases in Lombardy]

PURPOSE

The SIRM study group for senology in Lombardy set the following goals: to quantify the number of radiologist working in public radiology centers and in private credited hospitals in Lombardy; to quantify the number of radiologists working in diagnostic senology and the mean time they devote to this field; to survey the diagnostic equipment used for senology purposes and check its adequacy.

MATERIAL AND METHODS

We considered 58 centers of senology diagnostic imaging in the radiology departments of general hospitals in 8 Lombardy provinces. First we evaluated the screening programs for early breast cancer detection carried out with clinical mammography. All data were evaluated with reference to female residents aged 40 to 69, to the average adherence rates reported in the literature, to the protocols adopted in different centers relative to the examination frequency. Mammography was always associated with a physical examination and then the patient was submitted to radiological investigations to make the final diagnosis. The form we used for data report is summarized in Table I.

RESULTS

In the centers for diagnostic senology we surveyed in 1998, in all 182,724 mammograms, 58,686 breast US examinations and 7,097 needle biopsies for cytology or microhistology were performed; 35.5% of the female population which should have been screened actually underwent the examination and 32.6% of them was also submitted to breast US, while 3.88% underwent FNAB. Sixty-three mammographic units and 62 US units were operated by 152 radiologists. An average 2,900 radiographic investigations per mammographic unit were performed yearly. Each radiologist reported an average 1,202 mammograms a year. Refer to the tables for detailed data reporting by province. Thirty-six per cent of radiologists presently reads more than 1,500 breast examinations a year. The radiologists working in diagnostic imaging in senology devote an average 20% of their working time to this field. As for the technical adequacy of mammographic and US equipment relative to some reference levels reported in detail in the paper, only 42% of the former and 48% of the latter were up to standards.

DISCUSSION AND CONCLUSIONS

Despite the massive work done in the field of senology, the estimated needs of the female population have not been met yet, given the increased demand for senologic examinations and women's growing awareness of the need of early breast cancer diagnosis. The answer to this problem lies in a political health care policy that should promote the current clinical programs increasing both instrumental and human resources. Alternatively screening programs could be planned on a regional basis, with the pro of reaching a larger female population and that of a more homogeneous methodological approach. Our data indicate that breast cancer detection is best achieved with clinical and screening tools: the former can be easily promoted in a short time and could thus make our first goal, while the latter, which is more complex, could be implemented later. Thus, a growing clinical activity could make a very good basis for high quality breast screening programs. Finally, it is necessary to guarantee high quality standards for equipment, methods and training of medical and nonmedical staff.

Shear-induced structural transitions in newtonian non-newtonian two-phase flow

We show the existence under shear flow of steady states in a two-phase region of a brine-surfactant system in which lyotropic dilute lamellar (non-Newtonian) and sponge (Newtonian) phases are coexisting. At high shear rates and low sponge phase-volume fractions, we report on the existence of a dynamic transition corresponding to the formation of a colloidal crystal of multilamellar vesicles (or "onions") immersed in the sponge matrix. As the sponge phase-volume fraction increases, this transition exhibits a hysteresis loop leading to a structural bistability of the two-phase flow. Contrary to single phase lamellar systems where it is always 100%, the onion volume fraction can be monitored continuously from 0 to 100 %.

[Therapeutic and prophylactic role of mesalazine (5-ASA) in symptomatic diverticular disease of the large intestine. 4 year follow-up results]

In order to evaluate the efficacy and tolerability of mesalazine (5-ASA) in the prophylaxis of symptomatic relapses, of major complications and of microhemorrhagic phenomena in diverticular disease of the large intestine (MDC), prospective clinical study was conducted on patients with light-moderate symptomatic MDC under treatment with sulbactam-ampicillin 1.5 g/12 h i.m. and rifaximine 400 mg/12 h per os for 7 days. Follow-up period of 5 years with seriated checkups and laboratory and instrumentation controls. End points are represented by the relapse on inflammation and/or by the occurrence of major complications. On enrollment, 166 patients were randomized to receive mesalazine (Pentacol tablets--SOFAR S.p.A.) 400 mg b.i.d. per os for 8 weeks (81 patients; group M) or no supplementary treatment (85 patients; group C). After 4 years of follow-up, 44 patients dropped out of the study (9 because of major complications, 3 for massive hemorrhage, and 32 drop outs). Symptomatic relapses occurred in 51 patients (12 M; 39 C), while minor diverticular hemorrhages occurred in 43 patients (12 M; 31 C), with an estimated probability of remaining free respectively from symptomatic relapse (p=0.00005) and from microhemorrhagic phenomena (p=0.001) decisively in favor of the group treated with mesalazine. The duration of abdominal pain due to diverticolitis was also shorter in patients of group M (p=0.0002), while the incidence of major complications and side effects was comparable in the two groups. In conclusion, supplementary treatment with mesalazine in patients affected with MDC--at a follow-up limited to 48 months--proved to be well tolerated and effective in reducing the frequency of symptomatic relapses and microhemorrhagic phenomena and in reducing the duration of abdominal pain.

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.

[Efficacy of low dose mesalazine (5-ASA) in the treatment of acute inflammation and prevention of complications in patients with symptomatic diverticular disease. Preliminary results]

MATERIALS AND METHODS

To assess the efficacy of mesalazine in treating acute diverticulitis and preventing diverticular disease (DD) complication. 166 patients with symptomatic DD were randomly assigned to receive mesalazine Pentacol (400 mg b.i.d., orally; M group) or no additional treatment (controls; C group).

RESULTS

After a 12 months follow-up, 26 patients experienced a symptomatic relapse (8%M vs 27% C, p=0.003), with a higher rate in C group for the patients with a history of previous diverticulitis (p=0.006) and independently of the diverticular site (sigmoid p=0.041; colon and sigmoid p=0.044). Minor diverticular haemorrhages were less frequent in M group (p=0.016), with a significant difference only for the patients with sigmoid diverticula (p=0.023); abdominal pain persisted for a shorter time in the treated group (p=0.0015).

CONCLUSIONS

No significant difference was found between the two groups for the incidence of DD major complications.

[The diagnostic accuracy of a digital mammography system with photostimulable storage phosphors used with automatic reading]

Even though digital mammography might potentially yield major advantages in management, biology and diagnosis, state-of-the-art digitalization is still in a clinical experimental phase. To assess the diagnostic accuracy of a digital mammography system with storage phosphors, we analyzed 320 digital and 320 conventional mammograms acquired in lateral-oblique projection in the same patients. Digital mammography capabilities in identifying and characterizing breast lesions were compared with those of conventional mammography; the presence/absence of lesions and their benign/malignant nature were investigated. Complete conventional mammography was our gold standard. The digital system did not miss any malignant lesion but it did miss some benign lesions (focal masses) which had been depicted with conventional mammography, especially small low-contrast opacities. Microcalcifications were better depicted on digital images which showed, at the same time, tissues of different density, thanks to their wider dynamic range. Digital mammography yielded a false positive result on a cluster of microcalcifications, because its spatial resolution is lower. The diagnostic yield of digital mammography was poorer only in the detection of small low-contrast lesions and in the characterization of microcalcifications. To conclude, in our experience, the storage phosphor system seems to be suitable for clinical mammography, but only with careful monitoring; in contrast, we think it is not yet suitable for screening purposes.

The hypotonic effect of intranasal and intravenous glucagon in gastrointestinal radiology

In the present study, following a double-blind, double placebo protocol vs. placebo, we compared the hypotonic effect of intranasal and intravenous glucagon during a double-contrast barium meal examination of the stomach. We found a statistically significant difference between placebo and intranasal or intravenous glucagon in inducing gastric hypomotility, with no significant differences between IN and IV glucagon. The intranasal administration of glucagon has the advantage of being noninvasive and well tolerated by the patients, and might be a valuable aid in upper gastrointestinal examination as well as in CT scan or magnetic resonance imaging of the abdomen.

[Conventional radiography and digital radiography of the thorax: evaluation of anatomo-radiological parameters]

We report the results of a comparative study of digital and conventional chest radiographs to detect normal anatomical structures of the thorax. A digital Toshiba unit (TCR 201) was used to examine 100 selected patients who were diagnosed with no chest pathologic conditions. The images in both modes were submitted for interpretation to five radiologists. The depiction of nine normal anatomical structures was more accurate on digital than on conventional radiographs. The mean confidence levels achieved in viewing digital images were higher than those obtained with conventional radiographs. This difference was statistically significant (p = 0.002).

[Etiologic determination of chronic liver diseases]

Sixty patients with chronic liver conditions (mostly cirrhotic) were examined for HBV markers. The percentage of markers identified, far higher than in samples of healthy subjects, suggests that HBV either alone or in association with other causes may be implicated in the pathogenesis of these conditions.

[Intermittent chronic occlusion of the duodenum caused by pheochromocytoma]

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.