A cross-sectional study of psychological morbidity in patients with acne, psoriasis and atopic dermatitis in specialist dermatology and general practices.

BACKGROUND: There is considerable evidence for an association of skin diseases with psychological morbidity. This relationship is best established for acne, psoriasis and atopic eczema. Previous studies have mostly been performed in specialist dermatological practice, and there is a lack of studies that include patients from general practice and a lack of controlled studies employing multivariate analysis. AIMS/OBJECTIVES: This study aims to examine the relationship of acne, psoriasis and atopic eczema with psychological morbidities in patients recruited from general practice as well as specialist dermatology practice. METHODS AND SUBJECTS: In this cross-sectional study, 108 patients from general and specialist dermatology practices with the three diseases had disease severity assessed and completed measures of minor psychological disturbance (General Health Questionnaire-12), anxiety and depression (Hospital Anxiety and Depression Scale), public self-consciousness and social anxiety (Fenigstein Self-Consciousness Scale), and neuroticism and extraversion/introversion (Eysenck Personality Inventory). Demographic data were also collected, along with self-ratings of disease severity. Control subjects were 96 patients without skin disease recruited from the same general practices as the subjects. RESULTS: On univariate analyses, patients with skin disease had higher levels of minor psychological disturbance, public self-consciousness and neuroticism than did controls. There were no differences in psychological measures between specialist and general practice patients or between patients with different skin diseases. On multivariate analyses, the significant differences did not persist. CONCLUSIONS: This study demonstrates confounding in the relationship of skin diseases with psychological morbidity. The complex relationship of skin disease and psychological morbidity should be re-examined.

Mondor's disease of the breast: sonographic and mammographic findings.

OBJECTIVE: The purpose of this study was to evaluate the mammographic and sonographic findings in patients with Mondor's disease of the breast. CONCLUSION: The combination of a sonographic finding of a superficial vessel-with or without an intraluminal thrombus and without flow on Doppler imaging-and a mammographic finding of a tubular density is the typical sign of Mondor's disease of the breast. Women present with a palpable cordlike structure, which is often painful, especially in the acute phase of thrombophlebitis. An understanding of such an entity and knowledge of the imaging findings will help breast imagers avoid the pitfall of mistaking this finding for a dilated duct.

Allergic contact dermatitis due to benzalkonium chloride in plaster of Paris.

Plaster of Paris (POP) bandages are extensively used for splinting and casting injured or surgically repaired body parts. Allergic contact dermatitis caused by POP has been reported only rarely in the medical literature. An 81-year-old woman developed multiple large, tense, haemorrhagic bullae on the palm, and an acute vesicular eczematous eruption on the forearm, after the application of a POP splint. Subsequent patch testing revealed positive reactions to both the POP bandage used and to benzalkonium chloride, a component of the POP formulation. Patch tests to two other POP products without benzalkonium chloride were negative. These results confirm those of previous studies which have implicated the quaternary ammonium compound benzalkonium chloride as the allergen responsible for POP-induced allergic contact dermatitis.

Society of Breast Imaging residency and fellowship training curriculum.

A recently developed Society of Breast Imaging curriculum for residency training is intended to provide guidance to residents and their mentors, and to practicing radiologists who want to keep up to date in screening, diagnosis, and interventional procedures. The curriculum contains lists of key concepts in 14 subject areas: epidemiology; anatomy; pathology, and physiology; equipment and technique; quality control; interpretation; problem-solving mammography; ultrasound; interventional procedures; reporting and medicolegal aspects; screening; MR imaging; therapeutic considerations; and patient management principles. The curriculum also makes recommendations about residency training, including the number of examinations the resident should interpret, and the time the resident should spend in breast imaging. Recommendations for fellowship training are also discussed.

Visual detection of spatial contrast patterns: evaluation of five simple models.

The ModelFest Phase One dataset is a collection of luminance contrast thresholds for 43 two-dimensional monochromatic spatial patterns confined to an area of approximately two by two degrees. These data were collected by a collaboration among twelve laboratories, and were designed to provide a common database for calibration and testing of spatial vision models. Here I report fits of the ModelFest data with five models: Peak Contrast, Contrast Energy, Generalized Energy, a Gabor Channels model, and a Discrete Cosine Transform model. The Gabor Channels model provides the best fit, though the other, simpler models, with the exception of Peak Contrast, provide remarkably good fits as well. Though there are clear individual differences, regularities in the data suggest the possibility of constructing a standard observer for spatial vision.

Transducer model produces facilitation from opposite-sign flanks.

Small spots, lines and Gabor patterns can be easier to detect when they are superimposed upon similar spots, lines and Gabor patterns. Traditionally, such facilitation has been understood to be a consequence of nonlinear contrast transduction. Facilitation has also been reported to arise from non-overlapping patterns with opposite sign. We point out that this result does not preclude the traditional explanation for superimposed targets. Moreover, we find that facilitation from opposite-sign flanks is weaker than facilitation from same-sign flanks. Simulations with a transducer model produce opposite-sign facilitation.

Long-term follow up of patients with toenail onychomycosis after treatment with terbinafine.

The long-term outcome of 111 patients treated with oral terbinafine for toenail onychomycosis with a novel treatment protocol was assessed a median of 138 weeks after entry into the trial. All but three patients had either one or two 12 week courses of terbinafine 250 mg daily. Of the 77 evaluable patients, 72.7% were still classified as responders (i.e. negative mycological culture and at least 3 mm of new unaffected nail growth) on reassessment. The present study shows that a favourable long-term outcome can be achieved in patients who have been treated with at least one 12 week course of terbinafine.

Model of visual contrast gain control and pattern masking.

We have implemented a model of contrast gain and control in human vision that incorporates a number of key features, including a contrast sensitivity function, multiple oriented bandpass channels, accelerating nonlinearities, and a devisive inhibitory gain control pool. The parameters of this model have been optimized through a fit to the recent data that describe masking of a Gabor function by cosine and Gabor masks [J. M. Foley, "Human luminance pattern mechanisms: masking experiments require a new model," J. Opt. Soc. Am. A 11, 1710 (1994)]. The model achieves a good fit to the data. We also demonstrate how the concept of recruitment may accommodate a variant of this model in which excitatory and inhibitory paths have a common accelerating nonlinearity, but which include multiple channels tuned to different levels of contrast.

Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise.

Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

Visibility of wavelet quantization noise.

The discrete wavelet transform (DWT) decomposes an image into bands that vary in spatial frequency and orientation. It is widely used for image compression. Measures of the visibility of DWT quantization errors are required to achieve optimal compression. Uniform quantization of a single band of coefficients results in an artifact that we call DWT uniform quantization noise; it is the sum of a lattice of random amplitude basis functions of the corresponding DWT synthesis filter. We measured visual detection thresholds for samples of DWT uniform quantization noise in Y, Cb, and Cr color channels. The spatial frequency of a wavelet is r 2-lambda, where r is display visual resolution in pixels/degree, and lambda is the wavelet level. Thresholds increase rapidly with wavelet spatial frequency. Thresholds also increase from Y to Cr to Cb, and with orientation from lowpass to horizontal/vertical to diagonal. We construct a mathematical model for DWT noise detection thresholds that is a function of level, orientation, and display visual resolution. This allows calculation of a "perceptually lossless" quantization matrix for which all errors are in theory below the visual threshold. The model may also be used as the basis for adaptive quantization schemes.

Non-dermatophytes in onychomycosis of the toenails.

A multicentre trial for the treatment of dermatophyte onychomycosis of the toenails with terbinafine was carried out in Australia and New Zealand. Between eight and 12 nail samples were obtained from each of the 118 patients in the 48-week trial, and each sample was investigated by direct microscopy and culture for dermatophyte and non-dermatophyte fungi. Patients were randomized to treatment with terbinafine at 250 mg/day or placebo for the first 12 weeks of the study, then non-responders were offered a 12-week course of terbinafine from week 28. All patients had a dermatophyte infection. In 42 patients (36%) microscopy and mycological culture identified dermatophytes alone. In the remaining 76 patients (64%), a non-dermatophyte mould or yeast was also isolated at some stage during the trial, but in only three patients did the same non-dermatophyte persist in two or more successive nail specimens. The presence of a fungal contaminant in addition to a dermatophyte had no apparent effect on the efficacy of treatment with terbinafine. We conclude that non-dermatophyte moulds and yeasts are generally found as contaminating organisms in dermatophyte onychomycosis, secondary to the dermatophytes, and that they do not influence the outcome of treatment.

Examination of the ability of people to identify early changes of melanoma in computer-altered pigmented skin lesions.

OBJECTIVES: To examine whether older people were less able to distinguish changes of melanoma than younger people, and to test whether an educational brochure illustrating changes of melanoma would increase their ability to detect the changes. DESIGN: Photographic images of pigmented skin lesions were altered using computer graphics software. Images of typical changes of melanoma were shown to groups of volunteers younger than 30 years (n = 52) and older than 45 years (n = 41). Short intervals (seconds) between viewing of the original and changed lesions were used to test ability to distinguish the changes, and longer intervals (29 and 60 days) were used to test their ability over more realistic intervals. All participants were randomized to receive an educational brochure (designed using the same technology) to evaluate whether this would assist in identifying early changes of melanoma. SETTING: A cross section of volunteers employed in a large semigovernment utility. INTERVENTION: An educational brochure that illustrated typical changes of melanoma. MAIN OUTCOME MEASURE: Score of correct or incorrect detection of changed or unchanged skin lesions. RESULTS: Tests at short intervals showed that both age groups were able to detect early changes of melanoma but had poor ability to detect changes of melanoma at longer intervals. Repeated viewing of the original lesions enabled the participants to once more recognize the changes. Both groups had low ability to detect the appearance of new pigmented lesions. The educational brochure improved the ability of participants to detect change. CONCLUSIONS: The main difficulty people have in self-detection of melanoma is limited ability to recall the appearance of their skin. This ability did not differ between the age groups. Educational material that focused on change was effective in increasing the ability to detect changes over short intervals. Photographic records may be the most effective aid for detection of changes at longer intervals.

Imaging the temporal fossa.

OBJECTIVE: The purpose of our study was to delineate the interconnections in the temporal fossa that are visible on high-resolution clinical images. SUBJECTS AND METHODS: Thin-section MR images and CT scans of the temporal fossa in two normal volunteers were obtained in coronal and axial sections. MR images, CT scans, or both of 20 patients with demonstrable spread of disease were reviewed. RESULTS: The imaging studies of patients with disease proved more informative than images of the normal subject or the published anatomic and surgical descriptions of the temporal fossa. We recognized five discrete radiographically defined regions: the connective tissue layer, compartment of the superficial fat pad, compartment of the deep fat pad, compartment of the temporal muscle (superior recess of the suprazygomatic masticator), and subperiosteal zone. Important, tortuous, and to our knowledge undescribed interconnections between the scalp, posterior neck, eyelid, face, and the suprazygomatic masticator were delineated. CONCLUSION: Imaging studies of the temporal fossa can be used to formulate a clinically useful approach that simplifies the complex anatomy of the temporal fossa.

Psychophysica: Mathematica notebooks for psychophysical experiments (cinematica--psychometrica--quest).

Psychophysica is a set of software tools for psychophysical research. Functions are provided for calibrated visual displays, for fitting and plotting of psychometric functions, and for the QUEST adaptive staircase procedure. The functions are written in the Mathematica programming language.

Significance of non-dermatophyte moulds and yeasts in onychomycosis.

In a multicentre, randomised, double-blind, 48-week clinical trial, 118 patients with toe-nail onychomycosis were given terbinafine (250 mg daily) or placebo for 12 weeks, followed by 12 weeks of observation. Non-responders were offered 12 further weeks of terbinafine (250 mg daily) from week 28. Each patient had 8-12 consecutive nail specimens collected from the same nail, allowing for an assessment of the fungal nail flora from 1,321 nail specimens. By week 48, the overall mycological cure rate for terbinafine patients was 94%. 64% of patients had an underlying dermatophyte infection with at least 1 non-dermatophyte mould or yeast isolated from at least 1 specimen. These contaminants often overgrow or mask the presence of a dermatophyte. In only 2.5% of all patients was the same non-dermatophyte isolated from 2 or more consecutive specimens, probably representing secondary colonisation which exploits nutrients released by the underlying dermatophyte. The presence of incidental non-dermatophyte contaminants or secondary colonisers did not affect treatment outcome, and in this study treatment of the primary dermatophyte pathogen with terbinafine cleared the nails from infection in all cases. 80% of patients remained mycologically negative after 2 years.

Object detection in natural backgrounds predicted by discrimination performance and models.

Many models of visual performance predict image discriminability, the visibility of the difference between a pair of images. We compared the ability of three image discrimination models to predict the detectability of objects embedded in natural backgrounds. The three models were: a multiple channel Cortex transform model with within-channel masking; a single channel contrast sensitivity filter model; and a digital image difference metric. Each model used a Minkowski distance metric (generalized vector magnitude) to summate absolute differences between the background and object plus background images. For each model, this summation was implemented with three different exponents: 2, 4 and infinity. In addition, each combination of model and summation exponent was implemented with and without a simple contrast gain factor. The model outputs were compared to measures of object detectability obtained from 19 observers. Among the models without the contrast gain factor, the multiple channel model with a summation exponent of 4 performed best, predicting the pattern of observer d's with an RMS error of 2.3 dB. The contrast gain factor improved the predictions of all three models for all three exponents. With the factor, the best exponent was 4 for all three models, and their prediction errors were near 1 dB. These results demonstrate that image discrimination models can predict the relative detectability of objects in natural scenes.

Cinematica: a system for calibrated, Macintosh-driven displays from within Mathematica.

Cinematica is a minimal system for producing calibrated grayscale movies on an Apple Macintosh computer from within the Mathematica programming environment. It makes use of the ISR Video Attenuator and the Video Toolbox software library developed by Denis Pelli. By design, Cinematica provides a very low-level interface to the display routine. Display instructions take the form of a list of pairs (image index, colormap index). The philosophy is that programming is much easier in Mathematica than in C, so we reserve the complexity for Mathematica. A few simple examples are provided.

The effect of an educational brochure on knowledge and early detection of melanoma.

Men over the age of 45 present with thicker, more advanced melanomas than younger people. A randomised trial was conducted in this group to evaluate whether an educational brochure would increase knowledge about melanoma and the ability to recognise and discriminate between pigmented skin lesions. Men in an industrial complex were allocated to an intervention group (n = 110) and two control groups (n = 96 and n = 108). The intervention group was given two educational brochures about melanoma. Their effect on knowledge and ability to detect pigmented lesions was assessed by a questionnaire and a self-examination body chart given before the brochure, and at four weeks and three months after return of the brochure. The control groups did not receive any educational material, but control group 2 received the questionnaire and chart. At the end of the study all participants were examined for pigmented lesions by doctors, whose counts were compared with those of the participants. There was a significant (19.8 per cent) increase in knowledge about melanoma in the intervention group (but not in the control groups), except for discrimination of photos of benign and malignant lesions. The educational material did not improve the ability of those in the intervention group to recognise and count their pigmented lesions nor to discriminate between benign and malignant pigmented lesions. The increased knowledge about melanoma was retained for at least three months.

The optimal motion stimulus.

Contrast energy thresholds were measured for discriminating the direction of a drifting sinusoidal grating multiplied by an independently drifting space-time Gaussian (a generalized Gabor). We argue that the stimulus with the lowest contrast energy threshold identifies the receptive field of the most efficient linear motion filter. This optimal motion stimulus is found to be at 3 c/deg and 5 Hz, with a width and height of 0.44 deg and a duration of 0.133 sec, corresponding to spatial and temporal bandwidths of 1.1 and 2.5 octaves, respectively. The spectral receptive field is aligned more nearly to the Cartesian axes than to the velocity contour.