Improving radiologist's ability in identifying particular abnormal lesions on mammograms through training test set with immediate feedback.

It has been shown that there are differences in diagnostic accuracy of cancer detection on mammograms, from below 50% in developing countries to over 80% in developed world. One previous study reported that radiologists from a population in Asia displayed a low mammographic cancer detection of 48% compared with over 80% in developed countries, and more importantly, that most lesions missed by these radiologists were spiculated masses or stellate lesions. The aim of this study was to explore the performance of radiologists after undertaking a training test set which had been designed to improve the capability in detecting a specific type of cancers on mammograms. Twenty-five radiologists read two sets of 60 mammograms in a standardized mammogram reading room. The first test set focused on stellate or spiculated masses. When radiologists completed the first set, the system displayed immediate feedback to the readers comparing their performances in each case with the truth of cancer cases and cancer types so that the readers could identify individual-based errors. Later radiologists were asked to read the second set of mammograms which contained different types of cancers including stellate/spiculated masses, asymmetric density, calcification, discrete mass and architectural distortion. Case sensitivity, lesion sensitivity, specificity, receiver operating characteristics (ROC) and Jackknife alternative free-response receiver operating characteristics (JAFROC) were calculated for each participant and their diagnostic accuracy was compared between two sessions. Results showed significant improvement among radiologists in case sensitivity (+ 11.4%; P < 0.05), lesion sensitivity (+ 18.7%; P < 0.01) and JAFROC (+ 11%; P < 0.01) in the second set compared with the first set. The increase in diagnostic accuracy was also recorded in the detection of stellate/spiculated mass (+ 20.6%; P < 0.05). This indicated that the performance of radiologists in detecting malignant lesions on mammograms can be improved if an appropriate training intervention is applied after the readers' weakness and strength are identified.

Interpretative characteristics and case features associated with the performances of radiologists in reading mammograms: A study from a non-screening population in Asia.

AIMS: To explore radiologist characteristics and case features associated with diagnostic performances in cancer detection on mammograms in a South East Asian population. METHODS: Fifty-three radiologists reported 60 mammographic examinations which consisted of 40 normal and 20 cancer-containing cases at the BREAST workshops. Radiologists were asked to examine each mammogram using the BIRADS on diagnostic monitors. Differences in reader characteristics and case features between correct and incorrect decisions were assessed separately for cancer and normal cases. Univariate and multivariate logistic regressions were applied to generate odds ratios (OR) for significant factors related to correct decisions. RESULTS: Radiologists who spent ≥10 hours/week reporting mammograms had a higher possibility of detecting cancer lesions (OR = 1.6; P = 0.01). A higher rate of accuracy in reporting negative cases was associated with female radiologists (OR = 1.4; P = 0.002), radiologists who read ≤20 mammograms per week (OR = 1.5; P < 0.0001), had completed training course (OR = 1.7; P < 0.0001) or wore eyeglasses (OR = 1.4; P = 0.01). Cancer cases with breast density >50% (OR = 2.1; P < 0.0001), having abnormal lesions ≥9 mm (OR = 1.8; P < 0.0001), or displaying calcifications, a discrete mass or nonspecific density (OR = 1.6; P < 0.0001) were recorded with a higher detection rate by radiologists than other cases. Lesions located on the right breasts (OR = 1.8; P < 0.0001) or found in the lower inner, upper outer or mixed locations (OR = 2.7; P < 0.0001) were also recorded with a better diagnostic possibility compared with other lesions. CONCLUSION: This work identified key features related to diagnostic accuracy of breast cancer on mammograms in a nonscreening population, which is helpful for developing appropriate strategies to improve breast cancer detectability of radiologists.

Mammographic interpretation in Vietnam: Tailored educational strategies are needed to increase clinicians' expertise.

AIM: Breast cancer incidence is rapidly increasing throughout South East Asia, highlighting the need for high-quality early diagnosis and treatment. This study aims to investigate the efficacy of mammography detection in Hanoi and Ho Chi Minh City (HCMC), Vietnam, using data from Australian radiologists as a benchmark; factors that influence performance will be highlighted. METHODS: A total of 53, 35 and 52 clinicians from Australia, HCMC and Hanoi, respectively, examined and diagnosed a test set of 60 mammograms, 20 of which contained cancers. Each clinician completed an accompanying questionnaire establishing demographic and experiential characteristics. The performance metrics of specificity, sensitivity, area under the receiver operating characteristic curve (AUC), location sensitivity and Jackknife free-response ROC (JAFROC) figure of merit were used to evaluate clinicians performance. Mann-Whitney and Kruskal-Wallis statistical methods were employed to establish significance. RESULTS: Vietnamese radiologists demonstrated significantly lower sensitivity, AUC, lesion sensitivity and JAFROC scores compared to Australian radiologists. There was no difference in performance between clinicians from Hanoi and HCMC. However, certain performance features (older and more experienced clinicians compared with their younger, less experienced counterparts, readers who read more compared with fewer mammograms per week, clinicians with greater radiological experience and clinicians that completed a fellowship) demonstrated significantly better performances. CONCLUSIONS: The significant difference in diagnostic efficacy of mammograms between Vietnam and Australia identifies the need for improvements in breast radiology training, management and practice. Cost-effective solutions are available that can improve the reading efficacy of clinicians, and consequently health outcomes for Vietnamese women.

Convergent and parallel evolution in life habit of the scallops (Bivalvia: Pectinidae).

BACKGROUND: We employed a phylogenetic framework to identify patterns of life habit evolution in the marine bivalve family Pectinidae. Specifically, we examined the number of independent origins of each life habit and distinguished between convergent and parallel trajectories of life habit evolution using ancestral state estimation. We also investigated whether ancestral character states influence the frequency or type of evolutionary trajectories. RESULTS: We determined that temporary attachment to substrata by byssal threads is the most likely ancestral condition for the Pectinidae, with subsequent transitions to the five remaining habit types. Nearly all transitions between life habit classes were repeated in our phylogeny and the majority of these transitions were the result of parallel evolution from byssate ancestors. Convergent evolution also occurred within the Pectinidae and produced two additional gliding clades and two recessing lineages. Furthermore, our analysis indicates that byssal attaching gave rise to significantly more of the transitions than any other life habit and that the cementing and nestling classes are only represented as evolutionary outcomes in our phylogeny, never as progenitor states. CONCLUSIONS: Collectively, our results illustrate that both convergence and parallelism generated repeated life habit states in the scallops. Bias in the types of habit transitions observed may indicate constraints due to physical or ontogenetic limitations of particular phenotypes.

Examining the phylogeny of the Australasian Lymnaeidae (Heterobranchia: Pulmonata: Gastropoda) using mitochondrial, nuclear and morphological markers.

We examined the species groups relationships of the freshwater snail genus Austropeplea using mitochondrial, nuclear and morphological markers in addition to traditional methods of shell shape analysis. Based primarily on the results of a combined molecular and morphological analysis, samples of the nominal species A. tomentosa form distinct lineages. The New Zealand populations of A. tomentosa are a very distinct lineage from any of the Australian populations attributed to A. tomentosa. Furthermore, within the Australian group, three lineages, south Australia, Tasmania and eastern Australia, appear to have undergone recent and/or rapid speciation events. Samples assigned to A. lessoni were resolved as two distinct lineages, representing the eastern and northern Australian populations. Kutikina hispida was resolved within the Australian A. tomentosa clade. Molecular results for A. viridis suggests that it is also composed of at least two distinct lineages that could be treated as species. Incongruence observed between the single mitochondrial, nuclear and morphological topologies highlight the importance of using a number of different datasets in the delimitation of species-group taxa.

Molecular phylogenetics of the Pectinidae (Mollusca: Bivalvia) and effect of increased taxon sampling and outgroup selection on tree topology.

Evolutionary relationships of the Pectinidae were examined using two mitochondrial genes (12S rRNA, 16S rRNA) and one nuclear gene (Histone H3) for 46 species. Outgroup taxa from Propeamussidae, Spondylidae and Limidae were also sequenced to examine the impact of outgroup choice on pectinid topologies. Our phylogenetic analyses resolved the Pectinidae as monophyletic, but many of the subfamilies and tribes within the family do not form monophyletic clades. The paraphyletic Aequipectinini group is the most basal member of the Pectinidae, with the Chlamydinae and Palliolinae representing the most recently derived pectinid groups. These results are in contrast with the current morphological hypothesis of Pectinidae evolution, which suggests the Chlamydinae and Pallioline are basal groups within the Pectinidae. Ingroup topology was found to be sensitive to outgroup choice and increasing taxon sampling within the Pectinidae resulted in more robust phylogenies.