Impact of Transfer Learning Using Local Data on Performance of a Deep Learning Model for Screening Mammography.

Purpose To investigate the issues of generalizability and replication of deep learning models by assessing performance of a screening mammography deep learning system developed at New York University (NYU) on a local Australian dataset. Materials and Methods In this retrospective study, all individuals with biopsy or surgical pathology-proven lesions and age-matched controls were identified from a South Australian public mammography screening program (January 2010 to December 2016). The primary outcome was deep learning system performance-measured with area under the receiver operating characteristic curve (AUC)-in classifying invasive breast cancer or ductal carcinoma in situ (n = 425) versus no malignancy (n = 490) or benign lesions (n = 44). The NYU system, including models without (NYU1) and with (NYU2) heatmaps, was tested in its original form, after training from scratch (without transfer learning), and after retraining with transfer learning. Results The local test set comprised 959 individuals (mean age, 62.5 years ± 8.5 [SD]; all female). The original AUCs for the NYU1 and NYU2 models were 0.83 (95% CI: 0.82, 0.84) and 0.89 (95% CI: 0.88, 0.89), respectively. When NYU1 and NYU2 were applied in their original form to the local test set, the AUCs were 0.76 (95% CI: 0.73, 0.79) and 0.84 (95% CI: 0.82, 0.87), respectively. After local training without transfer learning, the AUCs were 0.66 (95% CI: 0.62, 0.69) and 0.86 (95% CI: 0.84, 0.88). After retraining with transfer learning, the AUCs were 0.82 (95% CI: 0.80, 0.85) and 0.86 (95% CI: 0.84, 0.88). Conclusion A deep learning system developed using a U.S. dataset showed reduced performance when applied "out of the box" to an Australian dataset. Local retraining with transfer learning using available model weights improved model performance. Keywords: Screening Mammography, Convolutional Neural Network (CNN), Deep Learning Algorithms, Breast Cancer Supplemental material is available for this article. © RSNA, 2024 See also commentary by Cadrin-Chênevert in this issue.

The PERFORM-P (Principles of Evidence-based Reporting in FORensic Medicine-Pathology version).

INTRODUCTION: Most findings of forensic pathology examinations are presented as written reports. There are currently no internationally accepted recommendations for writing forensic pathology reports. Existing recommendations are also varied and reflect the differences in the scope and role of forensic medical services and local settings in which they are to be implemented. The legal fact-finder thus faces wide variation in the quality of forensic pathology reports, which poses a threat to the reliability of legal decision-making. To address this issue, the development of the "PERFORM-P (Principles of Evidence-based Reporting in FORensic Medicine-Pathology version)" was undertaken. The goal of the PERFORM-P is to provide common practice recommendations adaptable to local requirements to promote evidence-based practice (EBP) in forensic pathology. METHODS: An international consensus study was conducted in three phases by (1) developing a long-list of items to be considered in the reporting recommendations, (2) conducting a Delphi process (an iterative survey method to transform individual opinions into group consensus) with international forensic pathologists, and (3) designing the PERFORM-P prototype and its accompanying manual. RESULTS: With assistance from 106 forensic pathologists/forensic medical practitioners from 41 countries, the PERFORM-P was developed. The PERFORM-P consists of a list of 61 items to be included in a forensic pathology report, which is accompanied by its Explanation and Elaboration (E&E) document. DISCUSSION: To prepare forensic pathology (postmortem) reports that incorporate principles of evidence-based practice, internationally accepted recommendations might be helpful. The PERFORM-P identifies recommendations for necessary elements to include in a forensic pathology report. PERFORM-P can be applied to a wide range of matters requiring forensic pathological analysis, acceptable to forensic pathologists from a representative selection of jurisdictions and medico-legal systems.

A survey of clinicians on the use of artificial intelligence in ophthalmology, dermatology, radiology and radiation oncology.

Artificial intelligence technology has advanced rapidly in recent years and has the potential to improve healthcare outcomes. However, technology uptake will be largely driven by clinicians, and there is a paucity of data regarding the attitude that clinicians have to this new technology. In June-August 2019 we conducted an online survey of fellows and trainees of three specialty colleges (ophthalmology, radiology/radiation oncology, dermatology) in Australia and New Zealand on artificial intelligence. There were 632 complete responses (n = 305, 230, and 97, respectively), equating to a response rate of 20.4%, 5.1%, and 13.2% for the above colleges, respectively. The majority (n = 449, 71.0%) believed artificial intelligence would improve their field of medicine, and that medical workforce needs would be impacted by the technology within the next decade (n = 542, 85.8%). Improved disease screening and streamlining of monotonous tasks were identified as key benefits of artificial intelligence. The divestment of healthcare to technology companies and medical liability implications were the greatest concerns. Education was identified as a priority to prepare clinicians for the implementation of artificial intelligence in healthcare. This survey highlights parallels between the perceptions of different clinician groups in Australia and New Zealand about artificial intelligence in medicine. Artificial intelligence was recognized as valuable technology that will have wide-ranging impacts on healthcare.

European council of legal medicine (ECLM) guidelines for the examination of suspected elder abuse.

Article 25 of the Charter of Fundamental Rights of the European Union (adopted in Nice on 7 December 2000) recognizes and respects the rights of older people to lead a life of dignity and independence and to participate in social and cultural life. It also highlights the importance of prevention and recognition of elder abuse, especially since exposure to violence is likely as the population ages, either in familial or in institutional settings. Elder abuse has some issues in common with child abuse but in spite of this fact currently is less recognized. Health professionals have a major role to play in early detection and management of cases of elder abuse. This protocol summarizes some key concepts and approaches to assist in the timely detection and investigation of elder abuse cases by healthcare professionals and forensic practitioners.

Evaluation of a computer-aided detection (CAD)-enhanced 2D synthetic mammogram: comparison with standard synthetic 2D mammograms and conventional 2D digital mammography.

AIM: To evaluate the diagnostic performance of computer-aided detection (CAD)-enhanced synthetic mammograms in comparison with standard synthetic mammograms and full-field digital mammography (FFDM). MATERIALS AND METHODS: A CAD-enhanced synthetic mammogram, a standard synthetic mammogram, and FFDM were available in 68 breast-screening cases recalled for soft-tissue abnormalities (masses, parenchymal deformities, and asymmetric densities). Two radiologists, blinded to image type and final assessment outcome, retrospectively read oblique and craniocaudal projections for each type of mammogram. The resulting 204 pairs of 2D images were presented in random order and scored on a five-point scale (1, normal to 5, malignant) without access to the Digital breast tomosynthesis (DBT) slices. Receiver operating characteristic (ROC) curve analysis was performed. RESULTS: There were 34 biopsy-proven malignancies and 34 normal/benign cases. Diagnostic accuracy was significantly improved for the CAD-enhanced synthetic mammogram compared to the standard synthetic mammogram (area under the ROC curve [AUC]=0.846 and AUC=0.683 respectively, p=0.004) and compared to the conventional 2D FFDM (AUC=0.724, p=0.027). The CAD-enhanced synthetic mammogram had the highest diagnostic accuracy for all soft-tissue abnormalities, and for malignant lesions sensitivity was not affected by tumour size. For all 68 cases, there was an average of 3.2 areas enhanced per image. For the 34 cancer cases, 97.4% of lesions were correctly enhanced, with 2.1 false areas enhanced per image. CONCLUSIONS: CAD enhancement significantly improves performance of synthetic 2D mammograms and also exhibits improved diagnostic accuracy compared to conventional 2D FFDM.

Contrast-enhanced spectral mammography (CESM).

Contrast-enhanced spectral mammography (CESM) is a valuable tool in the diagnosis and staging of primary breast cancer. It combines an iodinated contrast agent with conventional mammography to improve diagnostic accuracy, particularly in women with denser parenchymal background patterns. This review describes the CESM technique, reviews performance compared to conventional mammography and magnetic resonance imaging, assesses its role in the diagnosis and staging of primary breast cancer, and investigates its potential as a screening tool.

Measuring performance in the interpretation of chest radiographs: a pilot study.

AIM: To develop a system to assess the image interpretation performance of radiologists in identifying signs of malignancy on chest radiographs. MATERIALS AND METHODS: A test set of 30 chest radiographs was chosen by an experienced radiologist consisting of 11 normal and 19 abnormal cases. The malignant cases all had biopsy-proven pathology; the normal and benign cases all had at least 2 years of imaging follow-up. Fourteen radiologists with a range of experiences were recruited. Participants individually read the test set displayed on a standard reporting workstation, with their findings entered directly into a laptop running specially designed reporting software. For each case, relevant clinical information was given and the reader was asked to mark any perceived abnormality and rate their level of suspicion on a five-point scale (normal, benign, indeterminate, suspicious, or malignant). On completion, participants were given instant feedback with performance parameters including sensitivity and specificity automatically calculated. An opportunity was then given to review the cases together with an expert opinion and pathology. The time each participant took to complete the test was recorded. RESULTS: Six consultant radiologists who took part showed significantly better performance as determined by receiver operating characteristic (ROC) analysis compared to eight specialist registrars (area under the ROC curve [AUC]=0.9297 and 0.7648 respectively, p=0.003). There was a significant correlation with years of experience in the interpretation of chest radiographs and performance on the test set (r=0.573, p=0.032). Consultant radiologists completed the test significantly more quickly that the specialist registrars: mean time 19.65 minutes compared to 26.51 minutes (p=0.033). CONCLUSION: It is possible to use a test set to measure individual differences in the interpretation of chest radiographs. This has the potential to be a useful tool in performance testing.

Contrast-enhanced spectral mammography improves diagnostic accuracy in the symptomatic setting.

AIM: To assess the diagnostic accuracy of contrast-enhanced spectral mammography (CESM), and gauge its "added value" in the symptomatic setting. MATERIALS AND METHODS: A retrospective multi-reader review of 100 consecutive CESM examinations was performed. Anonymised low-energy (LE) images were reviewed and given a score for malignancy. At least 3 weeks later, the entire examination (LE and recombined images) was reviewed. Histopathology data were obtained for all cases. Differences in performance were assessed using receiver operator characteristic (ROC) analysis. Sensitivity, specificity, and lesion size (versus MRI or histopathology) differences were calculated. RESULTS: Seventy-three percent of cases were malignant at final histology, 27% were benign following standard triple assessment. ROC analysis showed improved overall performance of CESM over LE alone, with area under the curve of 0.93 versus 0.83 (p<0.025). CESM showed increased sensitivity (95% versus 84%, p<0.025) and specificity (81% versus 63%, p<0.025) compared to LE alone, with all five readers showing improved accuracy. Tumour size estimation at CESM was significantly more accurate than LE alone, the latter tending to undersize lesions. In 75% of cases, CESM was deemed a useful or significant aid to diagnosis. CONCLUSION: CESM provides immediately available, clinically useful information in the symptomatic clinic in patients with suspicious palpable abnormalities. Radiologist sensitivity, specificity, and size accuracy for breast cancer detection and staging are all improved using CESM as the primary mammographic investigation.

CT staging for breast cancer patients with poor prognostic tumours.

The aim of this study was to assess the value of computed tomography (CT) staging of the chest, abdomen and pelvis in patients with poor prognostic tumours and no symptoms of metastatic disease in those who have undergone primary surgical management for the treatment of breast cancer. Patients who had primary operable invasive breast cancer treated by surgery over a 2-year period were retrospectively identified. Pathological data from the surgical resection were used to calculate the Nottingham Prognostic Index. Patients with no symptoms of distant metastases who underwent CT staging of the chest, abdomen and pelvis as a result of being placed in the poor prognostic group were identified. The presence and sites of metastatic disease or any indeterminate finding were documented. Additional investigations generated as a result of the staging CT and the outcome were also recorded. Sixty-seven patients (80%) in the poor prognostic group underwent a staging CT. Forty-seven patients (70%) had no signs of metastatic disease on the staging CT. Two patients (3%) were diagnosed with metastatic disease, on the basis of the initial CT scan. Eighteen patients (27%) had an indeterminate finding requiring further investigation, generating 21 additional imaging tests - following this only one additional patient was diagnosed with metastatic disease. Seventeen patients with an initially indeterminate finding did not have metastatic disease, giving a false-positive rate of 25%. In total, three patients (4%) had a final diagnosis of metastatic disease. The routine use of CT staging in patients with no symptoms of distant metastases with primary operable breast cancer even when in a poor prognostic group is of limited value, with a low pick-up rate of metastatic disease and considerable risk of false-positive findings.

Does the insertion of a gel-based marker at stereotactic breast biopsy allow subsequent wire localizations to be carried out under ultrasound guidance?

AIM: To investigate whether the insertion of a gel-based marker at the time of stereotactic breast biopsy allows subsequent preoperative localization to be performed under ultrasound guidance. MATERIALS AND METHODS: One hundred consecutive women who underwent either a 10 G stereotactic vacuum-assisted breast biopsy or 14 G stereotactic core biopsy with marker placement, followed by wire localization and surgical excision were identified. All had mammographic abnormalities not initially visible with ultrasound. The method of preoperative localization was recorded and its success judged with reference to the wire position on the post-procedure films relative to the mammographic abnormality and the marker. Histopathology data were reviewed to ensure the lesion had been adequately excised. RESULTS: Eighty-three women (83%) had a successful ultrasound-guided wire localization. Successful ultrasound-guided localization was more likely after stereotactic vacuum biopsy (86%) compared to stereotactic core biopsy (68%), although this did not quite reach statistical significance (p=0.06). CONCLUSION: The routine placement of a gel-based marker after stereotactic breast biopsy facilitates preoperative ultrasound-guided localization.

The prognostic significance of computerised tomography findings in women with liver metastases from breast cancer.

AIMS: While computerised tomography (CT) is used for diagnosis and assessing response to treatment little work has been performed on the prognostic significance of the CT findings in women with liver metastases. The aim of this study was to assess if the CT findings in women diagnosed with liver metastases at the time of first presentation with metastatic breast cancer have any prognostic significance. MATERIALS AND METHODS: The staging CT scans of 78 consecutive women diagnosed with liver metastases at the time of first presentation of metastatic breast cancer were reviewed independently by two radiologists who were blinded to survival and the histological features of the tumour. The number and enhancement characteristics of liver metastases, whether metastases were solitary, multiple or diffuse, the diameter of the largest and the sum of the diameter of the five largest lesions, an estimate of % involvement (<10%, 10-50%, >50%), and the presence of metastases at other sites were assessed. HER-2 and ER status and histological grade of the patient's primary breast cancer were also recorded. Survival was ascertained from hospital records. The prognostic significance of these factors was assessed in a univariate and multivariate fashion. RESULTS: At univariate analysis, number of liver metastases, sum of the diameter of the five largest lesions, percentage estimated involvement, presence of ascites, chest metastases and HER-2 status were significantly associated with reduced survival. Liver metastasis pattern (i.e. whether discrete or multiple), enhancement characteristics, ER status and histological grade were not associated with a significant outcome. At multivariate analysis estimated percentage liver involvement and the presence of chest metastases retained prognostic significance. Estimated percentage involvement was reproducible with 90% concordance between the two observers. CONCLUSIONS: The CT appearances of patients with liver metastases at first presentation with metastatic breast cancer provide prognostic information which may be clinically useful.

Managing soil nitrogen to restore annual grass-infested plant communities: effective strategy or incomplete framework?

Theoretical and empirical work has established a positive relationship between resource availability and habitat invasibility. For nonnative invasive annual grasses, similar to other invasive species, invader success has been tied most often to increased nitrogen (N) availability. These observations have led to the logical assumption that managing soils for low N availability will facilitate restoration of invasive plant-dominated systems. Although invasive annual grasses pose a serious threat to a number of perennial-dominated ecosystems worldwide, there has been no quantitative synthesis evaluating the degree to which soil N management may facilitate restoration efforts. We used meta-analysis to evaluate the degree to which soil N management impacts growth and competitive ability of annual and perennial grass seedlings. We then link our analysis to current theories of plant ecological strategies and community assembly to improve our ability to understand how soil N management may be used to restore annual grass-dominated communities. Across studies, annual grasses maintained higher growth rates and greater biomass and tiller production than perennials under low and high N availability. We found no evidence that lowering N availability fundamentally alters competitive interactions between annual and perennial grass seedlings. Competitive effects of annual neighbors on perennial targets were similar under low and high N availability. Moreover, in most cases perennials grown under competition in high-N soils produced more biomass than perennials grown under competition in low-N soils. While these findings counter current restoration and soil N management assumptions, these results are consistent with current plant ecological strategy and community assembly theory. Based on our results and these theories we argue that, in restoration scenarios in which the native plant community is being reassembled from seed, soil N management will have no direct positive effect on native plant establishment unless invasive plant propagule pools and priority effects are controlled the first growing season.

Frequency and patterns of metastatic disease in locally advanced inflammatory and non-inflammatory breast cancer.

AIMS: To determine the frequency and pattern of metastatic disease as detected by staging computed tomography in patients presenting with locally advanced primary breast cancer, comparing non-inflammatory and inflammatory subtypes. MATERIALS AND METHODS: Patients who underwent staging computed tomography for locally advanced breast cancer were identified from the hospital's computerised radiology system. The computed tomography scans, breast imaging and pathology were reviewed. RESULTS: Over a 29 month period, 97 patients underwent staging computed tomography for locally advanced primary breast cancer. Sixteen patients (16%) were found to have metastatic disease at presentation. Thirty-eight patients (39%) presented with the inflammatory subtype and 59 patients (61%) with the non-inflammatory subtype. Metastases were significantly more likely in patients with the inflammatory subtype, with 10 patients (26%) having metastases at presentation compared with six patients (10%) with the non-inflammatory subtype (P=0.034). Metastases to the lung and the pleura were the most commonly encountered sites, with pleural-based metastases more likely in patients with the inflammatory subtype (P=0.05). CONCLUSION: Routine computed tomography staging of patients with locally advanced breast cancer is worthwhile with the inflammatory subtype of locally advanced disease having the higher risk of metastatic disease at presentation. Pleural-based metastatic disease is more likely in patients with the inflammatory subtype.

Healthcare issues of detainees in police custody in London, UK.

Little is known about the general healthcare needs of detainees in police custody. The aims of this study were to: determine the level of general health issues, diseases and/or pathology for detainees in police custody, and to determine how well those general health issues, diseases and/or pathology are being managed. This was done by a detailed analysis of healthcare issues of a cohort of detainees and reviewing intended and prescribed medication needs with current medication availability. In August 2007, a prospective detailed, anonymised, structured questionnaire survey was undertaken of 201 detainees in police custody in London, UK. Of these 83.6% consented to participate in the study. 85.1% of subjects were male; mean age was 33.9 years; 70.8% had English as a first language; 13.7% were of no fixed abode; 70.2% were registered with a general practitioner (primary care physician); 25% were already in contact with other healthcare teams; 7.1% had previously been sectioned under the Mental Health Act 1983; 16.7% had previously intentionally self-injured; 33.9% were dependent on heroin, 33.9% on crack cocaine; 25% on alcohol, 16.6% on benzodiazepines and 63.1% on cigarettes. 56% of subjects had active medical conditions; of those with active medical conditions 74% were prescribed medication for those medical conditions; only 3/70 had their medication available. 28/70 were not taking medication regularly, and many were not taking it at all. Three subjects who had deep vein thromboses were not taking their prescribed anticoagulants and six subjects with severe mental health issues were not taking their anti-psychotic medication. Mental health issues and depression predominated, but there was a very large range of mixed diseases and pathology. Asthma, epilepsy, diabetes, deep vein thrombosis, pulmonary embolism, hepatitis, and hypertension were all represented. The study has achieved its aims and has also shown that--in part because of the chaotic lifestyle of many detainees--appropriate care was not being rendered, thereby, putting both detainee, and potentially others coming into contact with them, at risk.

Provision of forensic medical services to police custody suites in England and Wales: current practice.

INTRODUCTION: Police services within England and Wales are required under the Police and Criminal Evidence Act 1984 to ensure appropriate healthcare to those detained in police custody (forensic medical services). Traditionally doctors have been used by police services to provide an appropriate level of care. Changes within the Act allowed other healthcare professionals (nurses and paramedics and emergency care practitioners) to be included in the provision of such services. The aim of this appears at least in part to have been to reduce the costs of providing such a service. In recent years police services within England and Wales have been outsourced to assorted commercial providers. There are now several different modes of delivery of forensic medical services, which are determined locally by separate police services. AIMS: This study aimed (a) to determine the different modes of delivery of forensic medical services in England and Wales; (b) to determine the healthcare workload caused by Police and Criminal Evidence Act 1984 Codes of Practice; (c) to determine the relative costs of different service models and (d) to determine availability of such information from the police services. METHODS: The study was undertaken in two parts--(a) a telephone survey of all police services, and (b) an application to each police service utilising the Freedom of Information Act 2000. RESULTS: All police services (n=43) in England and Wales were contacted. Of the 41 forces that furnished detailed information; 13/41 had a doctor only service; 20/41 had a doctor/nurse service; 6/41 had a doctor/nurse/paramedic service; 1/41 had a doctor/emergency care practitioner service (who may be nurses or paramedic); 1/41 had a doctor/paramedic service. 23/43 services were outsourced to private commercial providers. Mean cost per patient contact (in 17/43 services which supplied data) was GBP 97.25. The cheapest cost per patient contact was the Metropolitan Police Service - a doctor only service (GBP 56.4), the highest Lincolnshire--a doctor only service (GBP 151.1). Mean cost for a doctor only service was GBP 97.1; for a doctor/nurse service--GBP 91.56 and for a doctor/nurse/paramedic service--GBP 115.76. There was no significant difference in costs per patient contact between a doctor only versus mixed HCP delivery of service. Relative costs and 95% confidence intervals expressed as a percentage show that a doctor only model was on average 3.4% lower than a mixed HCP provision, and that a non-outsourced service was on average 9.9% less than an outsourced service. No outsourced service in this study uses a doctor only model. CONCLUSIONS: The study shows that there was a complete lack of consistency in the recording and availability of information regarding forensic medical services for police services in England and Wales. The information that was obtained suggested that usage of such services varied greatly between police services and that costs of forensic medical services appear to be increased by the use of mixed healthcare professional service delivery and by using external commercial providers.

Does computer-aided detection have a role in the arbitration of discordant double-reading opinions in a breast-screening programme?

AIMS: To investigate whether a computer-aided detection (CAD) system could act as an arbitrator of discordant double-reading opinions, replacing the need for an independent third film reader. METHODS: The mammograms of the 240 women that underwent arbitration by an independent third reader were identified from the 16,629 women attending our screening centre between July 2003 and April 2004. Mammograms of the arbitration cases were digitized and analysed by a CAD system. To assess the ability of CAD to act as the arbitrator, the site of the CAD prompts was retrospectively compared to the site of any abnormality noted by the original film readers. If a CAD prompt was placed on a region marked by one of the film readers then the decision of CAD as the arbitrator was that the women should be recalled for further assessment. If no mark was placed then the region was considered low risk and the decision was not to recall. The decision of CAD as the arbitrator was retrospectively compared with the original recall decision of the independent third reader. RESULTS: There were 21 cancer cases in the group of women undergoing arbitration, diagnosed both at the original screening episode and subsequently. The independent third reader recalled 15/18 (83%) of the cancers that corresponded with the arbitrated lesion. CAD as the arbitrator would have recalled 16/18 (89%) of the cancers that corresponded to the arbitrated lesion. CAD acting as the arbitrator would have resulted in a significant increase in normal women being recalled to assessment in the arbitration group (P<0.001). The extra 50 recalls would have potentially increased the overall recall rate to assessment from 3.1 to 3.4%; a relative increase of 10%. CONCLUSIONS: The main effect of CAD acting as an arbitrator of discordant double-reading opinions is to increase the recall rate, significantly above what is found when arbitration is performed by an independent third reader. Using CAD as an arbitrator may be an option to deal with discordant double-reading opinions when no other method of consensus or arbitration is available.

Linking nitrogen partitioning and species abundance to invasion resistance in the Great Basin.

Resource partitioning has been suggested as an important mechanism of invasion resistance. The relative importance of resource partitioning for invasion resistance, however, may depend on how species abundance is distributed in the plant community. This study had two objectives. First, we quantified the degree to which one resource, nitrogen (N), is partitioned by time, depth and chemical form among coexisting species from different functional groups by injecting (15)N into soils around the study species three times during the growing season, at two soil depths and as two chemical forms. A watering treatment also was applied to evaluate the impact of soil water content on N partitioning. Second, we examined the degree to which native functional groups contributed to invasion resistance by seeding a non-native annual grass into plots where bunchgrasses, perennial forbs or annual forbs had been removed. Bunchgrasses and forbs differed in timing, depth and chemical form of N capture, and these patterns of N partitioning were not affected by soil water content. However, when we incorporated abundance (biomass) with these relative measures of N capture to determine N sequestration by the community there was no evidence suggesting that functional groups partitioned different soil N pools. Instead, dominant bunchgrasses acquired the most N from all soil N pools. Consistent with these findings we also found that bunchgrasses were the only functional group that inhibited annual grass establishment. At natural levels of species abundance, N partitioning may facilitate coexistence but may not necessarily contribute to N sequestration and invasion resistance by the plant community. This suggests that a general mechanism of invasion resistance may not be expected across systems. Instead, the key mechanism of invasion resistance within a system may depend on trait variation among coexisting species and on how species abundance is distributed in the system.

Can computerised tomography replace bone scintigraphy in detecting bone metastases from breast cancer? A prospective study.

BACKGROUND: The aim of this study was to determine whether bone scans (BS) can be avoided if pelvis was included in CT thorax and abdomen to detect bony metastases from breast cancer. MATERIALS AND METHODS: Results of 77 pairs of CT (thorax, abdomen, and pelvis) and BS in newly diagnosed patients with metastatic breast cancer (MBC) were compared prospectively for 12 months. Both scans were blindly assessed by experienced radiologists and discussed at multidisciplinary team meetings regarding the diagnosis of bone metastases. RESULTS: CT detected metastatic bone lesions in 43 (98%) of 44 patients with bone metastases. The remaining patient had a solitary, asymptomatic bony metastasis in shaft of femur. BS was positive in all patients with bone metastases. There were 11 cases of false positive findings on BS. CONCLUSION: Our findings suggest routine BS of patients presenting with MBC is not required if CT (thorax, abdomen, and pelvis) is performed.

Pseudosclerodermatous triad of perniosis, pulp atrophy and 'parrot-beaked' clawing of the nails--a newly recognized syndrome of chronic crack cocaine use.

The number of people dependent on crack-cocaine in the UK has increased substantially in recent years. Some crack-cocaine users develop coarsening changes in the appearance of their hands after prolonged use of the drug. These changes have most often been recognized in females and include: (i) Perniosis with cold, numb hands, sometimes with perniotic hyperkeratosis over the knuckles.(ii) Finger pulp atrophy of the distal part of the pulps of some digits, especially the thumbs and index fingers.(iii) Claw-like curvature of the nails. As the distal pulp is lost, it can no longer splint the nail straight and so the nail curves, claw-like, and reminiscent of a parrot's beak as it clings to the new contour. As the pulp atrophy progresses, the nail eventually also becomes smaller.This triad may be due to ischemia consequent upon peripheral vasoconstriction induced by crack-cocaine. Early changes may resolve with abstinence. In the patients described the syndrome does not appear to be to related to intravenous drug usage. It may occur without concomitant use of heroin, whether smoked or via the intravenous route. The syndrome does not occur in all crack-cocaine users. It is hypothesized that those with a vasoreactive circulation (i.e., those with vasomotor instability/perniosis) are more susceptible to this reaction pattern. The syndrome consisting of the triad of perniosis, pulp atrophy and parrot-beaked clawing of the nails should alert the clinician to the possibility of prolonged crack-cocaine misuse.