Prediction of complicated appendicitis risk in children.

OBJECTIVE: We aimed to predict the risk of complicated appendicitis in children, constructing a risk-based prediction tool with the optimal combination of sensitivity and specificity outcomes. PATIENTS AND METHODS: This is a prospective study on a random sample of children with acute appendicitis who underwent appendectomy. Clinical examination, history, routine laboratory tests, Alvarado and pediatric appendicitis scores, operative and histopathological findings were taken into consideration. The predictive ability of the outcome variables was assessed by the Receiver Operating Characteristics (ROC) analysis. The overall predictive ability and determination of the best cut-off value (the higher sum of sensitivity plus specificity) were calculated. A Classification and Regression Tree (CRT) was used to create a multi-level classification algorithm. The model was set to predict the outcome of complicated appendicitis, considering as potential predictors the demographic characteristics, the clinical findings, and the outcome parameters. RESULTS: The various combinations of clinical and laboratory parameters did not improve their overall diagnostic ability. However, the CRT analysis resulted in a short classification algorithm based on the Pediatric appendicitis score, neutrophils percentage and the CRP. This model yielded a significantly better predictive ability than all the other combinations of the outcome parameters. The application of the model would predict complicated appendicitis with 90% sensitivity and 78.6% specificity. CONCLUSIONS: The constructed predictive model may be a useful tool for daily practical use by the clinician, especially in areas where modern diagnostic imaging facilities are absent or not always available. Clinical evaluation and close follow-up remain the more accurate preoperative method to decide the performance and timing of appendectomy.

Behavioural and emotional profile of children in residential care in Greece.

Previous research has shown the harmful effects that out of home care can have on children. Specifically, institutionalized children experience high rates of developmental and psychological problems, and therefore special attention is needed so that a fast intervention can be achieved and further complications can be prevented. This paper focuses on building the psychological and behavioural profile of children living in four residential care units in western Greece, in respect to gender, age and nationality. 153 children (88 children in residential care and 65 children rearing in their families) participated in the study. The children age ranged from 6 to 18 years. Children's behavioural profile was assessed through Child Βehaviour Checklist 6-18 (CBCL 6-18) and was afterwards analyzed with respect to variables such as age, gender and nationality. Children in residential care had higher rates of clinical/borderline range symptoms in Internalizing, Externalizing and Total Problems scale than their counterparts rearing at home. Specifically, they were more withdrawn/ depressed and tended to indicate more rule-breaking behaviour. Both genders showed vulnerability in Internalizing behaviour scale, but girls presented higher rates than boys in the clinical range in Externalizing behaviour scale (22% vs 12%) and Total Problems scale (24% vs 5%). Finally, adolescents in residential care exhibit more internalizing symptoms in clinical range than younger children (22% vs 0%), whereas children of Greek nationality were more vulnerable than children of other nationalities, especially in externalizing behavioural symptoms (28% vs 6%). Our study suggests that children in residential care are at high risk for developing mental health issues. The finding that children are more withdrawn and depressed underlines the possible difficulties in establishing confident relations with peers and adults and can destruct their orientation towards social reality, exhibit mistrust to other people and cause insecurity for their future. There is a lack of longitudinal studies investigating children who have lived in institutions in Greece. Such studies would possibly reveal protective or aggravating parameters that have a positive or negative impact on the development of those children and the transition to adult life.

A two-stage method for microcalcification cluster segmentation in mammography by deformable models.

PURPOSE: Segmentation of microcalcification (MC) clusters in x-ray mammography is a difficult task for radiologists. Accurate segmentation is prerequisite for quantitative image analysis of MC clusters and subsequent feature extraction and classification in computer-aided diagnosis schemes. METHODS: In this study, a two-stage semiautomated segmentation method of MC clusters is investigated. The first stage is targeted to accurate and time efficient segmentation of the majority of the particles of a MC cluster, by means of a level set method. The second stage is targeted to shape refinement of selected individual MCs, by means of an active contour model. Both methods are applied in the framework of a rich scale-space representation, provided by the wavelet transform at integer scales. Segmentation reliability of the proposed method in terms of inter and intraobserver agreements was evaluated in a case sample of 80 MC clusters originating from the digital database for screening mammography, corresponding to 4 morphology types (punctate: 22, fine linear branching: 16, pleomorphic: 18, and amorphous: 24) of MC clusters, assessing radiologists' segmentations quantitatively by two distance metrics (Hausdorff distance-HDISTcluster, average of minimum distance-AMINDISTcluster) and the area overlap measure (AOMcluster). The effect of the proposed segmentation method on MC cluster characterization accuracy was evaluated in a case sample of 162 pleomorphic MC clusters (72 malignant and 90 benign). Ten MC cluster features, targeted to capture morphologic properties of individual MCs in a cluster (area, major length, perimeter, compactness, and spread), were extracted and a correlation-based feature selection method yielded a feature subset to feed in a support vector machine classifier. Classification performance of the MC cluster features was estimated by means of the area under receiver operating characteristic curve (Az ± Standard Error) utilizing tenfold cross-validation methodology. A previously developed B-spline active rays segmentation method was also considered for comparison purposes. RESULTS: Interobserver and intraobserver segmentation agreements (median and [25%, 75%] quartile range) were substantial with respect to the distance metrics HDISTcluster (2.3 [1.8, 2.9] and 2.5 [2.1, 3.2] pixels) and AMINDISTcluster (0.8 [0.6, 1.0] and 1.0 [0.8, 1.2] pixels), while moderate with respect to AOMcluster (0.64 [0.55, 0.71] and 0.59 [0.52, 0.66]). The proposed segmentation method outperformed (0.80 ± 0.04) statistically significantly (Mann-Whitney U-test, p < 0.05) the B-spline active rays segmentation method (0.69 ± 0.04), suggesting the significance of the proposed semiautomated method. CONCLUSIONS: Results indicate a reliable semiautomated segmentation method for MC clusters offered by deformable models, which could be utilized in MC cluster quantitative image analysis.

Assessing heterogeneity of lesion enhancement kinetics in dynamic contrast-enhanced MRI for breast cancer diagnosis.

The current study investigates the feasibility of using texture analysis to quantify the heterogeneity of lesion enhancement kinetics in order to discriminate malignant from benign breast lesions. A total of 82 biopsy-proven breast lesions (51 malignant, 31 benign), originating from 74 women subjected to dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) were analysed. Pixel-wise analysis of DCE-MRI lesion data was performed to generate initial enhancement, post-initial enhancement and signal enhancement ratio (SER) parametric maps; these maps were subsequently subjected to co-occurrence matrix texture analysis. The discriminating ability of texture features extracted from each parametric map was investigated using a least-squares minimum distance classifier and further compared with the discriminating ability of the same texture features extracted from the first post-contrast frame. Selected texture features extracted from the SER map achieved an area under receiver operating characteristic curve of 0.922 +/- 0.029, a performance similar to post-initial enhancement map features (0.906 +/- 0.032) and statistically significantly higher than for initial enhancement map (0.767 +/- 0.053) and first post-contrast frame (0.756 +/- 0.060) features. Quantifying the heterogeneity of parametric maps that reflect lesion washout properties could contribute to the computer-aided diagnosis of breast lesions in DCE-MRI.

Combining 2D wavelet edge highlighting and 3D thresholding for lung segmentation in thin-slice CT.

The first step in lung analysis by CT is the identification of the lung border. To deal with the increased number of sections per scan in thin-slice multidetector CT, it has been crucial to develop accurate and automated lung segmentation algorithms. In this study, an automated method for lung segmentation of thin-slice CT data is presented. The method exploits the advantages of a two-dimensional wavelet edge-highlighting step in lung border delineation. Lung volume segmentation is achieved with three-dimensional (3D) grey level thresholding, using a minimum error technique. 3D thresholding, combined with the wavelet pre-processing step, successfully deals with lung border segmentation challenges, such as anterior or posterior junction lines and juxtapleural nodules. Finally, to deal with mediastinum border under-segmentation, 3D morphological closing with a spherical structural element is applied. The performance of the proposed method is quantitatively assessed on a dataset originating from the Lung Imaging Database Consortium (LIDC) by comparing automatically derived borders with the manually traced ones. Segmentation performance, averaged over left and right lung volumes, for lung volume overlap is 0.983+/-0.008, whereas for shape differentiation in terms of mean distance it is 0.770+/-0.251 mm (root mean square distance is 0.520+/-0.008 mm; maximum distance is 3.327+/-1.637 mm). The effect of the wavelet pre-processing step was assessed by comparing the proposed method with the 3D thresholding technique (applied on original volume data). This yielded statistically significant differences for all segmentation metrics (p<0.01). Results demonstrate an accurate method that could be used as a first step in computer lung analysis by CT.

Dose and image quality optimization in neonatal radiography.

In a special care baby unit, neonates, mainly premature, encounter serious to life-threatening diseases, the timely diagnosis and treatment of which may require a large number of radiographs. Increased neonatal radiosensitivity and longer life expectancy increase the risk of radiation-induced cancer, which emphasizes the importance of minimizing dose while maintaining clinically satisfactory image quality. An optimization study on radiation dose and image quality in neonatal radiography is presented. Neonates were categorized into four groups depending on birthweight. For a total of 378 chest and chest-abdomen radiographs, exposure parameters were recorded. Entrance surface dose (ESD) was estimated and dose-area product (DAP) was measured. Image quality evaluation was performed by two observers and was based on the visibility of certain anatomical features and catheters placed during treatment using a five-grade scale. ESD values increased with neonatal weight and demonstrated wide variation (16.4-76.9 microGy, mean 38.2 microGy). A wide variation was also observed in DAP values (1.2-15.0 mGycm2, mean 7.2 mGycm2). Image quality evaluation revealed the feasibility of achieving a diagnostically satisfactory image (score >70%) using both low and high tube voltage techniques, with the latter resulting in reduced ESDs. The majority of estimated ESDs are in accordance with the reference level of 50 microGy recommended by the National Radiological Protection Board for neonatal radiography. The results suggest that the use of high tube voltage techniques could result in further reductions in neonatal dose, without image quality degradation, underlying the requirement for establishing standard examination protocols for neonatal radiography with respect to neonatal weight.

Texture analysis of perimenopausal and post-menopausal endometrial tissue in grayscale transvaginal ultrasonography.

The aim of this study was to investigate the feasibility of texture analysis in characterizing endometrial tissue as depicted in two-dimensional (2D) grayscale transvaginal ultrasonography. Digital transvaginal ultrasound endometrial images were acquired from 65 perimenopausal and post-menopausal women prior to gynaecological operations; histology revealed 15 malignant and 50 benign cases. Images were processed with a wavelet-based contrast enhancement technique. Three regions of interest (ROIs) were identified (endometrium, endometrium plus adjacent myometrium, layer containing endometrial-myometrial interface) on each original and processed image. 32 textural features were extracted from each ROI employing first and second order statistics texture analysis algorithms. Textural features-based models were generated for differentiating benign from malignant endometrial tissue using stepwise logistic regression analysis. Models' performance was evaluated by means of receiver operating characteristic (ROC) analysis. The best logistic regression model comprised seven textural features extracted from the ROIs determined on the processed images; three features were extracted from the endometrium, while four features were extracted from the layer containing the endometrial-myometrial interface. The area under the ROC curve (A(z)) was 0.956+/-0.038, providing 86.0% specificity at 93.3% sensitivity using the cut-off level of 0.5 for probability of malignancy. Texture analysis of 2D grayscale transvaginal ultrasound images can effectively differentiate malignant from benign endometrial tissue and may contribute to computer-aided diagnosis of endometrial cancer.

Texture analysis of tissue surrounding microcalcifications on mammograms for breast cancer diagnosis.

Diagnosis of microcalcifications (MCs) is challenged by the presence of dense breast parenchyma, resulting in low specificity values and thus in unnecessary biopsies. The current study investigates whether texture properties of the tissue surrounding MCs can contribute to breast cancer diagnosis. A case sample of 100 biopsy-proved MC clusters (46 benign, 54 malignant) from 85 dense mammographic images, included in the Digital Database for Screening Mammography, was analysed. Regions of interest (ROIs) containing the MCs were pre-processed using a wavelet-based contrast enhancement method, followed by local thresholding to segment MCs; the segmented MCs were excluded from original image ROIs, and the remaining area (surrounding tissue) was subjected to texture analysis. Four categories of textural features (first order statistics, co-occurrence matrices features, run length matrices features and Laws' texture energy measures) were extracted from the surrounding tissue. The ability of each feature category in discriminating malignant from benign tissue was investigated using a k-nearest neighbour (kNN) classifier. An additional classification scheme was performed by combining classification outputs of three textural feature categories (the most discriminating ones) with a majority voting rule. Receiver operating characteristic (ROC) analysis was conducted for classifier performance evaluation of the individual textural feature categories and of the combined classification scheme. The best performance was achieved by the combined classification scheme yielding an area under the ROC curve (A(z)) of 0.96 (sensitivity 94.4%, specificity 80.0%). Texture analysis of tissue surrounding MCs shows promising results in computer-aided diagnosis of breast cancer and may contribute to the reduction of unnecessary biopsies.

Evaluating the effect of a wavelet enhancement method in characterization of simulated lesions embedded in dense breast parenchyma.

Presence of dense parenchyma in mammographic images masks lesions resulting in either missed detections or mischaracterizations, thus decreasing mammographic sensitivity and specificity. The aim of this study is evaluating the effect of a wavelet enhancement method on dense parenchyma for a lesion contour characterization task, using simulated lesions. The method is recently introduced, based on a two-stage process, locally adaptive denoising by soft-thresholding and enhancement by linear stretching. Sixty simulated low-contrast lesions of known image characteristics were generated and embedded in dense breast areas of normal mammographic images selected from the DDSM database. Evaluation was carried out by an observer performance comparative study between the processed and initial images. The task for four radiologists was to classify each simulated lesion with respect to contour sharpness/unsharpness. ROC analysis was performed. Combining radiologists' responses, values of the area under ROC curve (Az) were 0.93 (95% CI 0.89, 0.96) and 0.81 (CI 0.75, 0.86) for processed and initial images, respectively. This difference in Az values was statistically significant (Student's t-test, P<0.05), indicating the effectiveness of the enhancement method. The specific wavelet enhancement method should be tested for lesion contour characterization tasks in softcopy-based mammographic display environment using naturally occurring pathological lesions and normal cases.

Visually lossless threshold determination for microcalcification detection in wavelet compressed mammograms.

The aim of this study was to determine the visually lossless threshold of a wavelet-based compression algorithm in case of microcalcification cluster detection in mammography. The threshold was determined by means of observer performance using a set of digitized mammograms. In addition, the transfer characteristics of the compression algorithm were assessed by means of image-quality parameters using computer-generated test images. The observer performance study was based on rating performed by four independent radiologists, who reviewed 68 mammograms, from the Digital Database for Screening Mammography (DDSM), at six different compression ratios. Receiver operating characteristics (ROC) analysis was performed on observers' responses and the area under ROC curve (A(z)) was calculated at each compression ratio for each observer. The parameters used for assessment of transfer characteristics of the compression algorithm were input/output response, noise, high-contrast response, and low-contrast-detail response. The computer-generated test image, used for this assessment, mimicked mammographic image characteristics (pixel size, pixel depth, and noise) as well as microcalcification characteristics (size and contrast). The ROC analysis for microcalcification cluster detection indicated a threshold at compression ratio 40:1, as Student's t-test shows statistically significant differences in A(z) values (p<0.05) for compression ratios 70:1 and 100:1. Observers' grading of mammogram quality lowers this threshold at 25:1. Low-contrast-detail detectability in the transfer characteristics study indicate a threshold of 35:1, whereas non-perceptibility of image-quality-parameters degradation lowers this threshold to 30:1. The ROC and transfer characteristics analysis provided comparable thresholds, indicating the potential use of the latter in limiting the target range of compression ratios for subsequent observer studies.

Simulating the mammographic appearance of circumscribed lesions.

Optimization performance of digital image post-processing techniques in mammography requires controlled conditions of data sets permitting quantitative representation of image characteristics of pathological findings. Digital test objects, although objective and quantitative, do not mimic mammographic appearance and clinical data sets do not provide adequate sets of values of the various pathological finding characteristics. This can be overcome by digital simulation of pathological findings and superimposition on mammographic images. A simple method for simulation of mammographic appearance of radiopaque and/or radiolucent circumscribed lesions is presented. Circumscribed lesions are simulated using grey-level transformation functions which shift and compress the range of the initial pixel grey-level values in a region of interest (ROI) of a digitized mammographic image, according to grey-level analysis in 200 ROIs of real circumscribed lesions from digitized mammographic images. Simulation addresses lesion image characteristics, such as elliptical shape, orientation, halo sign for radiopaque lesions and capsule for radiolucent lesions, and is implemented in a user-driven PC-based interactive application. The appearance of the lesions is evaluated by six radiologists on a sample of 60 real and 60 simulated radiopaque lesions with the use of receiver operating characteristic (ROC) analysis. The area under the ROC curve, pooling the responses of the observers, was 0.55+/-0.03 indicating no statistically significant difference between real and simulated lesions (p>0.05). The method adequately simulates the mammographic appearance of circumscribed lesions and could be used to generate circumscribed lesion data sets for performance evaluation of image processing techniques, as well as education purposes.

A phantom-based evaluation of an exposure equalization technique in mammography.

An anatomical filter based exposure equalization technique in mammography is evaluated quantitatively using a phantom. The evaluation is carried out by a comparative observer performance study, comparing the equalization technique with a conventional one based on visualization of low contrast, 6 mm circular details and high contrast, 0.5 mm and 0.25 mm small size details. These details are situated at the phantom edge, simulating the breast periphery. Visualization of these details is studied with respect to the parameters of tube voltage, optical density, detail location and phantom thickness. Phantom images are interpreted independently by three observers using a four-point grading scale. Use of the Wilcoxon signed ranks test for paired data shows statistically highly significant improvement (p < 0.0001) in the visualization of details for the equalization technique for all values of the parameters studied. The improvement is independent of tube voltage but dependent on optical density, detail location and phantom thickness. Optimal performance is obtained for detail location closer to the outer border of the simulated breast periphery and/or further away from the film, as well as for a greater phantom thickness simulating both thick and dense breast.

The sperm deformity and multiple anomalies indices: are they reliable in the identification of fertile and infertile semen?

DESIGN: Two new indices, the sperm deformity index and the multiple anomalies index, were evaluated in order to help identify fertile and infertile semen. RESULTS: It was found that only three out of 94 infertile men presented a sperm deformity index lower than the upper limits of normal. The sperm deformity index sensitivity and specificity were higher than those of the multiple anomalies index. CONCLUSION: The sperm deformity index is a reliable predictor in the identification of fertile and infertile semen, and therefore can help in the selection of patients who require assisted reproduction techniques.

Evaluation of an anatomical filter-based exposure equalization technique in mammography.

An anatomical filter-based exposure equalization technique in mammography is clinically evaluated. An observer performance comparative study, between this technique and the conventional one, is carried out on the basis of the visualization of six anatomical features situated at the breast periphery. The effect of parenchymal breast patterns and compressed breast thickness in the visualization of these features is studied. 533 craniocaudal mammograms were interpreted by two radiologists independently, using a five-point rating scale. Use of the Wilcoxon ranking test for unpaired data shows statistically highly significant improvement (p < 0.0001) in the visualization of the nipple, areola, skin and subcutaneous fat in all cases, for the equalization technique. The improvement is dependent on parenchymal breast patterns and compressed breast thickness for peripheral Cooper's ligaments and peripheral surface veins. In the case of total fatty replacement and/or thin breasts neither technique seems to be superior (p > 0.05) with respect to these two features. Clinical results indicate the value of this technique in clinical routine.

Evaluation of semen parameters in man with hyperprolactinemia induced by metoclopramide.

Hyperprolactinemia in man decreases libido and potency, but the few reports concerning its influence on spermatogenesis are contradictory. The aim of this study was to evaluate the effect of induced hyperprolactimemia on semen parameters. A total of 15 potentially fertile male volunteers, aged 28.2 +/- 4.3 years, were given 10 mg metoclopramide three times daily for 12 weeks. Serum and seminal plasma prolactin levels and semen parameters were determined before and 4, 8, and 12 weeks following initiation of metoclopramide administration. A fivefold increase of serum prolactin levels was observed, semen volume and abnormal sperm forms decreased, while spermatozoa velocity increased. On the contrary, no influence was noted on the number of spermatozoa per milliliter, the total number of spermatozoa, the percentage of motile spermatozoa, or the index of motility. Hyperprolactinemia seems to improve spermatozoal velocity and morphology, although direct effect of metoclopramide on these parameters cannot be excluded.

Suppression of serum prolactin levels after an oral glucose tolerance test in patients with polycystic ovarian syndrome.

In order to assess if an oral glucose load has any effect on serum prolactin levels in patients with polycystic ovary syndrome (PCOS), an oral glucose tolerance test (OGTT) was performed in 30 patients with PCOS and 20 controls, with normal or abnormal body mass index (BMI). OGTT resulted in decreased prolactin levels, being significant only in patients with PCOS and in controls with normal BMI. Our results show that obesity is an important inhibiting factor of serum prolactin level suppression which occurs with a mild suppressive test, as the OGTT; however, hyperandrogenemia may also play an inhibiting role in serum prolactin level suppression.

Does postprandial hypersinsulinemia contribute to hyperandrogenism in patients with polycystic ovary syndrome?

Twenty patients with polycystic ovarian syndrome and with or without insulin resistance, and 20 healthy women (controls) underwent an oral glucose tolerance test, which resulted in a short duration but significant increase of serum insulin levels. Serum testosterone, androstenedione and dehydroepiandrosterone sulfate levels were estimated before and 180 minutes after administration of 75 gr. dextrose. Our results, three hours after dextrose administration, showed that: (1) serum testosterone levels decreased significantly, (2) serum androstenedione levels decreased but not significantly, and (3) serum dehydroepiandrosterone sulfate levels were not altered. The observation of decreased ovarian androgen levels after induced hyperinsulinemia is very interesting, the explanation, however, is quite difficult. This unexpected ovarian androgen response needs further investigation.

Association of acanthosis nigricans with insulin resistance in patients with polycystic ovary syndrome.

This study was designed to explore the association of insulin resistance and acanthosis nigricans (AN) in patients with polycystic ovary syndrome (PCOS). Fifty women, 18-37 years old, were included in the study, and divided into five groups consisting of: (I) 10 women with PCOS, abnormal body mass index (BMI) and AN; (II) 10 women with PCOS and abnormal BMI, but without AN; (III) 10 women with PCOS, normal BMI, and no AN; (IV) 10 women with abnormal BMI, but without PCOS or AN; and (V) 10 healthy women with normal BMI. Measurement of fasting glucose and insulin levels before and after oral glucose challenge was performed. Fasting serum insulin levels were found to be significantly lower in groups III, IV and V than in groups I and II, with no significant difference between groups I and II, or between groups III, IV and V. Total insulin response following administration of glucose did not differ significantly between the groups. These findings support the view that obese PCOS patients with AN do not have significantly higher insulin resistance than obese patients without AN. Insulin resistance is a necessary, but not the only, factor leading to the development of AN in patients with PCOS. Other factors should also be considered in the pathogenesis of this cutaneous reaction.

Hypothalamic-pituitary deficiency after Weil's syndrome: a case report.

A case of male hypogonadism after Weil's syndrome is described. Hypogonadism was the result of complete hypothalamic-pituitary deficiency. The relationship between leptospirosis and the endocrinopathy, the incidence that leptospira attacks hypothalamic-pituitary axis, and the mechanism with which the microorganism may cause damage to the pituitary and/or the hypothalamus are discussed.

Familial blepharophimosis with ovarian dysfunction.

Three cases including two sisters and one brother with blepharophimosis are described. Their father also had blepharophimosis. Moreover, the elder sister initially presented with resistant ovary syndrome and thereafter true premature menopause, while the younger one presented with resistant ovary syndrome. The explanation for the association of blepharophimosis with primary ovarian dysfunction is unknown, but the possibility of a microdeletion of genetic material containing two geographically associated, but independent genes could not be confirmed or excluded. All families affected by blepharophimosis should be counselled about the high incidence of ovarian dysfunction and female infertility, at least in one form of the syndrome.