Assessment of Transcatheter or Surgical Closure of Atrial Septal Defect using Interpretable Deep Keypoint Stadiometry.

Automated echocardiogram interpretation with artificial intelligence (AI) has the potential to facilitate the serial diagnosis of heart defects by primary clinician. However, the fully automated and interpretable analysis pipeline for suggesting a treatment plan is largely underexplored. The present study targets to build an automatic and interpretable assistant for the transthoracic echocardiogram- (TTE-) based assessment of atrial septal defect (ASD) with deep learning (DL). We developed a novel deep keypoint stadiometry (DKS) model, which learns to precisely localize the keypoints, i.e., the endpoints of defects and followed by the absolute distance measurement with the scale. The closure plan and the size of the ASD occluder for transcatheter closure are derived based on the explicit clinical decision rules. A total of 3,474 2D and Doppler TTE from 579 patients were retrospectively collected from two clinical groups. The accuracy of closure classification using DKS (0.9425 ± 0.0052) outperforms the "black-box" model (0.7646 ± 0.0068; p < 0.0001) for within-center evaluation. The results in cross-center cases or using the quadratic weighted kappa as an evaluation metric are consistent. The fine-grained keypoint label provides more explicit supervision for network training. While DKS can be fully automated, clinicians can intervene and edit at different steps of the process as well. Our deep learning keypoint localization can provide an automatic and transparent way for assessing size-sensitive congenital heart defects, which has huge potential value for application in primary medical institutions in China. Also, more size-sensitive treatment planning tasks may be explored in the future.

Assessment of Therapeutic Benefit and Option Strategy on Intravesical Instillation for Preventing Bladder Cancer Recurrence after Radical Nephroureterectomy in Patients with Upper Urinary Tract Urothelial Carcinoma.

Objective: Upper urinary tract urothelial carcinoma (UUT-UC) is a very aggressive disease, characterized by 22%-50% of patients suffering from subsequent bladder recurrence after radical nephroureterectomy (RNU). Although the therapy of intravesical instillation is reported to be effective in preventing bladder recurrence, no study had been reported in Northeast China. The findings relating to the clinical effectiveness of intravesical instillation after RNU are somewhat controversial, and the best efficacy and least adverse effects of instillation drugs have not been widely accepted. Here, we aimed at evaluating the efficacy of intravesical instillation for the prevention intravesical recurrence systematically. Methods: In this retrospective cohort study, from October 2006 to September 2017, 158 UUT-UC patients underwent RNU were divided into 4 groups: epirubicin (EPB) instillation group, hydroxycamptothecin (HCPT) instillation group, bacillus Calmette-Guerin (BCG) instillation group, and noninstillation group. Cox univariate and multivariate analyses were employed to identify the risk factors for intravesical recurrence-free survival (IVRFS). The nomogram model was also applied to predict patient outcomes. Subsequently, to evaluate the clinical significance of intravesical instillation comprehensively, several databases including PubMed, Ovid, and Embase were searched and data from published studies with our results were combined by direct meta-analysis. Moreover, a network meta-analysis comparing instillation therapies was conducted to evaluate the clinical efficacy of different instillation drugs. Results: In our retrospective cohort study, the Kaplan-Meier survival curve demonstrated noninstillation groups were associated with worsened IVRFS. Meanwhile, multivariate analysis indicated that intravesical instillation was independent protective factors for IVRFS (hazard ratio [HR] = 0.731). Moreover, calibration plots, receiver operating characteristic (ROC) curves, area under the curve (AUC) values, and the C-index showed the priority of nomogram's predictive accuracy. Next, direct meta-analysis including 19 studies showed that intravesical instillation could prevent the recurrence of bladder cancer with a pooled risk ratio (RR) estimate of 0.53. Subgroup analysis by study type, year of intravesical recurrence, first instillation time, and instillation times also confirmed the robustness of the results. Moreover, intraoperative instillation was associated with a decrease in the risk of bladder recurrence compared with postoperative instillation. Then, a network meta-analysis including 7 studies indicated that pirarubicin (THP) (surface under the cumulative ranking curve [SUCRA] = 89.2%) is the most effective therapy to reduce the risk of bladder recurrence, followed by BCG (SUCRA = 83.5%), mitomycin C (MMC) (SUCRA = 53.6%), EPB (SUCRA = 52.6%), and HCPT (SUCRA = 5.1%) after the analysis of the value ranking. Conclusions: A maintenance schedule of intravesical instillation prevents the recurrence of bladder cancer after RNU in UUT-UC patients effectively. Large, prospective trials are needed to further confirm its value. Compared with other chemotherapy regimens, THP may be a promising drug with favorable efficacy to prevent bladder recurrence. As included studies had moderate risk of bias, the results of network meta-analysis should be applied with caution.

Can Aspirin Use Be Associated With the Risk or Prognosis of Bladder Cancer? A Case-Control Study and Meta-analytic Assessment.

Aspirin, widely used to prevent cardiovascular disease, had been linked to the incidence of bladder cancer (BCa). Existing studies focusing on Chinese populations are relatively rare, especially for Northeast China. Meanwhile, relevant studies on the effects of aspirin on the occurrence or prognosis of BCa are inconsistent or even controversial. First, in the case control study, logistic regression analysis was used to investigate the association between aspirin intake and risk of BCa including 1121 patients with BCa and the 2242 controls. Subsequently, Kaplan-Meier curve and Cox regression analyses were applied to explore the association between aspirin intake and clinicopathological factors which may predict overall survival (OS) and recurrence-free survival (RFS) of BCa patients. Finally, we quantificationally combined the results with those from the published literature evaluating aspirin intake and its effects on the occurrence, outcome of surgery and prognosis of BCa by meta-analysis up to May 1, 2021.Our case-control study demonstrated that the regular use of aspirin was not associated with a reduced incidence of BCa (P=0.175). Stratified analyses of sex showed that aspirin intake did not lead to a lower risk of BCa in female patients (P=0.063). However, the male population who regularly took aspirin had a lower incidence of BCa (OR=0.748, 95% CI= 0.584-0.958, P=0.021). Subgroup analyses stratified by smoking found a significant reduction in the risk of BCa in current smokers with aspirin intake (OR=0.522, 95% CI=0.342-0.797, P=0.002). In terms of prognosis of BCa, patients with a history of aspirin intake did not had a markedly longer OS or RFS than those with no history of aspirin intake by Kaplan-Meier curves. Stratified analysis by sex showed no correlation between aspirin intake and the recurrence or survival of BCa for either male or female patients. However, in people younger than 68, aspirin intake seemed to have prolonged effects for overall survival (HR=3.876; 95% CI=1.326-11.325, P=0.019). Then, we performed a meta-analysis and the combined results from 19 articles and our study involving more than 39524 BCa cases indicated that aspirin intake was not associated with the occurrence of BCa (P=0.671). Subgroup analysis by whether regular use of aspirin, by the mean duration of use of aspirin, by sex, by smoking exposure, by research region and by study type also supported the above results. In terms of the impact of aspirin intake on the prognosis of patients with BCa, 11 articles and our study involving 8825 BCa cases were eligible. The combined results showed that patients with aspirin intake did not have significantly influence on survival, recurrence, progression and metastasis than those without aspirin intake. On the whole, both our retrospective study and literature meta-analysis suggested a lack of a strong relevant association between the use of aspirin and the incidence or prognosis of BCa. Thus, additional long-term follow-up prospective research is warranted to clarify the association of aspirin with BCa incidence and prognosis.

Exposure and tiered ecological risk assessment of phthalate esters in the surface water of Poyang Lake, China.

Phthalate esters (PAEs) are a class of endocrine disruptors that are produced and used extensively in China. Given its presence in various products, a great quantity of PAEs flows into different aquatic systems each year. Hence, it is important to study the pollution levels and ecological risk of PAEs. This study investigated the distribution and seasonal variation of six priority PAEs in the surface water of Poyang Lake, the largest freshwater lake in China. In the wet season, the mean concentration of the total PAEs was 0.544 ± 0.173 µg/L, while the dry season concentration (1.003 ± 0.451 µg/L) nearly doubled. The most abundant PAE congeners were di-n-butyl phthalate (DBP), followed by bis (2-ethylhexyl) phthalate (DEHP). To evaluate the ecological risks in Poyang Lake, the predicted no-effect concentrations (PNECs) of four PAEs based on non-lethal effects were derived. For diethyl phthalate (DEP), butyl benzyl phthalate (BBP), DBP, and DEHP, the PNECs were 31.6, 3.30, 2.31, and 0.0210 µg/L, respectively. The tiered ecological risk assessment showed that DEP and BBP posed no risk in Poyang Lake. Meanwhile, DBP posed a potential risk in Poyang Lake, but the risk of DEHP was unacceptable and requires more actions. Specifically, the probabilities of exceeding the threshold for the protection of 95% of the aquatic organisms (HC5) were 3.30% and 4.43% for DEHP in the wet and dry season, respectively. This study provides an appropriate reference for the surface water management of PAE pollution in China.

Ammonia spatiotemporal distribution and risk assessment for freshwater species in aquatic ecosystem in China.

Ammonia has been of concern for its high toxicity to aquatic species and frequent detection in waters worldwide. This study calculated the national aquatic life criteria for ammonia in China. The temporal and spatial distributions were investigated and the multi-tier ecological risks were assessed for ammonia and un-ionized ammonia (NH3) during 2014-2018 based on a total of 18989 ammonia monitoring data from 110 monitoring sites in seven river basins. The sensitivity comparison of different species taxa to ammonia showed that Perciformes fish should be listed as a priority protected species in the derivation of ammonia criteria. The participation of introduced aquaculture species have no significant impact on the final criteria values (t-test, p > 0.05). The final criterion maximum concentration (CMC) and criterion continuous concentration (CCC) were 10.24 and 3.31 mg/L for ammonia (pH 7.0 and 20 °C). The interannual variation showed that decreasing trends were observed for ammonia and NH3 pollutions in the past five years. However, the increasing trends were observed for ammonia in Liao River basin, for NH3 in Yangtze River and Pearl River basins (2014-2018). The significant seasonal and geographical differences of ammonia and NH3 pollution were found. Moreover, the pollutions of ammonia and NH3 in some monitoring points of Huai River, Yellow River and Songhua River basins at the provincial borders were significant. The result of ecological risk assessment showed that the average exceedance probability for 5% affected species by NH3 in long-term exposure was 28.96% in the past five years.

Intermachine differences in DXA measurements vary by skeletal site, and impact the assessment of low bone density in children.

BACKGROUND: Bone mineral content (BMC) and areal-bone mineral density (aBMD) measurements of the lumbar spine (LS) and whole body less head (WBLH) by dual energy X-ray absorptiometry (DXA) are recommended for bone health assessment in children. Intermachine differences were not considered previously in formulating these recommendations. METHODOLOGY: DXA measurements of the LS, WBLH, total hip, femoral neck and distal 1/3 radius from the Bone Mineral Density in Childhood Study were examined. Healthy children, ages 6 to 16 years, from five clinical centers participated. The same spine, whole body, and femur phantoms were measured on each Center's DXA machine. Percentage of individuals with low BMC or aBMD (Z-score < -1.5) was determined. Clinical center differences were evaluated by analysis of covariance adjusting for height and BMI Z-score, calcium intake, physical activity, Tanner stage and bone age. Logistic regression assessed odds of low BMC or aBMD across clinical centers. RESULTS: Significant differences among Clinical Centers (p < 0.05) were evident in adjusted mean BMC and aBMD Z-scores (n = 1503) for all skeletal sites. WBLH BMC and aBMD Z-scores had the greatest range across centers (-0.13 to 0.24, and -0.17 to 0.56, respectively). The percentage of children with Z-scores less than -1.5 varied among Clinical Centers from 1.9 [95%CI 0.8, 4.5] to 8.1 [95%CI 5.7, 11.3] for WBLH BMC, 1.1 [95%CI 0.4, 3.5] to 6.3 [95%CI 3.8, 10.1] for WBLH aBMD, and from 4.4 [95%CI 2.8, 7.0] to 12.6 [95%CI 9.3, 16.9] for distal 1/3 radius aBMD. For each skeletal site except total hip aBMD and femoral neck BMC, at least one center had significantly lower odds of low bone density. CONCLUSIONS: By design, our reference ranges capture intermachine variability. Most clinical centers don't know where their machine falls within the range of intermachine variability, and this may affect diagnosis of children evaluated for conditions that threaten bone health. Total hip scans showed the least, and whole body scans showed the most intermachine variability. Pediatric bone health assessment recommendations should recognize intermachine differences and address this important issue.

Development of human health ambient water quality criteria of 12 polycyclic aromatic hydrocarbons (PAH) and risk assessment in China.

Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in various environmental media and have thus attracted extensive attention worldwide. To prevent and control PAH pollution in China, the study of ambient water quality criteria (AWQC), human health risks, and aquatic ecological risk is critical. There are no reports to date on the human health AWQC of PAHs in China. Therefore, this study first derived the human health AWQC values of 12 PAHs based on exposure data and bioaccumulation factor in China. We found that local exposure parameters and other relevant factors were key during the development of AWQC in different countries and regions, which led to differences with the reference value recommended by USEPA. Based on the incremental life time cancer risk (ILCR), hazard quotients (HQ) and potentially affected fraction (PAF) methods, the health and ecological risks of 16 PAHs were assessed subsequently. And the results are as follows: the non-carcinogenic PAHs' health risks ranged from 1.01 × 10-10 to 1.60 × 10-9, and carcinogenic PAH health risks ranged from 5.03 × 10-7 to 4.74 × 10-5. The toxic effects of 8 PAHs on aquatic organisms exhibited the following order: benzo (a) pyrene (BaP) > anthracene (Ant) > pyrene (Pye) > phenanthrene (Phe) > fluoranthene (Flua) > acenaphthene (Ace) > fluorene (Flu) > naphthalene (Nap). Among these, the ecological risks posed by Ant and BaP were the highest, according to the HQ and PAF methods.

Aquatic life criteria derivation and ecological risk assessment of DEET in China.

N,N-diethyl-meta-toluamide (DEET) is the most widely used active ingredient in commercial insect repellents. In addition to its adverse effects in insects, DEET can affect non-target organisms in surface water systems. Nevertheless, the aquatic life criteria of DEET are not available. This study conducted both acute and chronic toxicity tests on DEET in native Chinese aquatic species, and derived its criterion maximum concentration (CMC) and criterion continuous concentration (CCC). The determined CMC and CCC of DEET were 21.53 and 0.52 mg/L, respectively. The toxicity data indicated that DEET exposure posed a higher toxicity to some algae than other aquatic species. Compared with other insect repellents, DEET exposure posed a moderate toxicity to aquatic species. Therefore, the exposure concentration of DEET in Chinese surface water was collected to assess the potential ecological risk. The preliminary ecological risk assessment showed that DEET posed negligible risk to aquatic ecosystems in China. However, considering its toxic effects on the growth and reproduction to aquatic organisms, the ecological risk posed by DEET is worth further concern.

Development of aquatic life criteria for tonalide (AHTN) and the ecological risk assessment.

AHTN (tonalide) is a polycyclic musk that is widely used as fragrance additive in numerous consumer products. AHTN is of great worldwide concern owing to its adverse effects on aquatic organisms and frequent detection in both domestic and foreign aquatic environments. Therefore, derivation of the aquatic life criteria for AHTN exposure is urgently needed. In this work, AHTN toxicity data for eight Chinese native freshwater organisms were used to derive a criterion maximum concentration of 59.39 µg/L and a criterion continuous concentration of 22.43 µg/L using United States Environmental Protection Agency guidelines. Toxicity tests showed that the annelid L. hoffmeisteri and the amphibian R. nigromaculata were the least and most sensitive species to AHTN, respectively. The sensitivity of the planktonic crustacean D. magna to AHTN obviously differed from that of the benthic crustacean M. nipponense. The AHTN and HHCB correlation analysis exhibited a strong positive linear correlation (R2 = 0.8622) in water. The ecological risk assessment showed that AHTN and HHCB posed a higher risk in foreign surface waters than Chinese waters, but a lower risk in foreign wastewater treatment plant effluent than in China. The ecological risks of AHTN and HHCB in most surveyed water bodies of various countries were at acceptable levels, with a few exceptions.

Study of aquatic life criteria and ecological risk assessment for triclocarban (TCC).

Triclocarban (TCC) is used as a broad-spectrum antimicrobial agent, the intensive detection of TCC in aquatic environments and its potential risks to aquatic organisms are concerned worldwide. In this study, 8 Chinese resident aquatic organisms from 3 phyla and 8 families were used for the toxicity tests, and four methods were employed to derive the aquatic life criteria (ALC). A criterion maximum concentration (CMC) of 1.46 µg/L and a criterion continuous concentration (CCC) of 0.21 µg/L were derived according to the USEPA guidelines. The acute predicted no effect concentrations (PNECs) derived by species sensitivity distribution (SSD) methods based on log-normal, log-logistic and Burr Type Ⅲ models were 2.64, 1.88 and 3.09 µg/L, respectively. The comparisons of ALCs derived with resident and non-resident species showed that the CMC and CCC of TCC derived with Chinese resident species could provide a sufficient protection for non-resident species. The higher toxicity of TCC on aquatic organisms was found compared with other antimicrobial agents (except for Clotrimazole) in aquatic environment. The strong positive linear correlation was observed between the TCC and TCS concentrations in aquatic environment with a correlation coefficient (R2) of 0.8104, it is of great significance in environmental monitoring and risk assessment for TCC and TCS. Finally, the ecological risk assessment showed that the TCC in Yellow River basin and Pearl River basin had higher risk with the mean potential affected fractions (PAFs) of 9.27% and 7.09%, and 22.10% and 15.00% waters may pose potential risk for 5% aquatic organisms, respectively. In general, the risk of TCC in Asian waters was higher than that in Europe and North America.

[Distribution and Risk Assessment of Polycyclic Aromatic Hydrocarbons in Water Bodies in Seven Basins of China].

The concentrations and spatial distribution characteristics of 16 US EPA priority Polycyclic Aromatic Hydrocarbons (PAHs) in water bodies in seven basins in China were systematically analyzed and summarized. The acute ecological risks of 8 PAHs to aquatic organisms were evaluated by means of species sensitivity distribution (SSD). The joint acute ecological risks of ΣPAH8 to aquatic organisms were evaluated by concentration addition model and response addition model. The health risks of PAHs ingestion were estimated by hazard quotients. The results showed that the 2-, 3-, and 4 ringed-PAHs had higher-than-average concentrations in the water bodies from the seven basins, and the mean concentration of ΣPAH16 was 2596.25 ng·L-1, which is higher than in most foreign water bodies. The composition characteristics and sources of PAHs in water bodies of China and other countries were similar. The pollution of ΣPAH16 in northern water bodies was more serious compared with that of southern water bodies. The potentially affected fraction (PAF) values of naphthalene, acenaphthene, fluorene, phenanthrene, fluoranthene, pyrene, and anthracene to aquatic organisms in the seven basins were less than 4%. Except for the Haihe River and Yangtze River basins, the PAF values of benzo (a) pyrene to aquatic organisms exceeded 5%, which indicates that benzo (a) pyrene had high acute ecological risks to aquatic organisms. The concentration addition model was not suitable for water ecological risk assessments of PAHs. The results of risk assessments based on response addition model showed that except for the Haihe River, the multisubstance PAF (msPAF) values of ΣPAH8 to aquatic organisms in other basins exceeded 5%, which indicates that ΣPAH8 constitutes high joint acute ecological risks to aquatic organisms. The health risks through ingestion of carcinogenic PAHs from water bodies of the seven basins were at 10-5 level, which is higher than the baseline value of acceptable risk (10-6) from the US EPA. The health risks through the ingestion of non-carcinogenic PAHs were at 10-9 level, which is far lower than the baseline value of acceptable risk. The results indicate that there are potential carcinogenic risks to human health through ingestion of PAHs from seven basins in China.

Deriving aquatic life criteria for galaxolide (HHCB) and ecological risk assessment.

The polycyclic musk galaxolide (HHCB) is widely used as fragrances in personal care products (PCPs) and has been detected in various environmental media. There is an urgent need to derive aquatic life criteria (ALC) of HHCB for the protection of aquatic organisms. Toxicity tests with 8 Chinese resident aquatic organisms from 3 phyla and 8 families were conducted, and three methods were used for deriving the ALC. A criterion maximum concentration (CMC) of 8.33 µg/L and a criterion continuous concentration (CCC) of 2.20 µg/L were derived according to the USEPA guidelines. The acute predicted no effect concentrations (PNECs) values derived by log-normal species sensitivity distribution (SSD) and log-logistic SSD method were 77.41 and 66.47 µg/L, respectively. In addition, a significant sensitivity difference was observed between the planktonic crustacean and benthic crustacean, and there was no significant difference (p > 0.05) among SSDs based on resident and non-resident species. A comparison of chronic SSDs between HHCB, tonalide (AHTN) and musk ketone (MK) showed that nitro musk (MK) was more toxic to aquatic organisms than polycyclic musks (HHCB and AHTN). Finally, an assessment of risk to aquatic organisms in surface waters and effluents of wastewater treatment plants (WWTPs) worldwide showed that potential risk may exist at several locations. HHCB concentrations in 4.08 and 46.17% of the WWTP effluents in China and 1.71 and 16.13% of the WWTP effluents in other countries exceed the hazard concentration for 5% and 1% aquatic species.

The comparison of an inexpensive-modified transobturator vaginal tape versus TVT-O procedure for the surgical treatment of female stress urinary incontinence.

OBJECTIVE: To compare the safety and efficacy of an inexpensive-modified transobturator vaginal tape procedure with the transobturator tension-free vaginal tape (TVT-O) procedure for the surgical treatment of female stress urinary incontinence (SUI). MATERIALS AND METHODS: Patients with SUI were randomly allocated to either the test group receiving the inexpensive-modified transobturator vaginal tape procedure or the control group receiving the GYNECARE TVT-O procedure. Treatment outcomes and Quality-of-life scores were recorded and analyzed between two groups. RESULTS: A total of 156 patients were enrolled in this trial. Eighty patients underwent the modified transobturator vaginal tape procedure. Among them 75(93.8%) were cured and 5(6.2%) were improved. The rest of the 76 patients underwent the GYNECARE TVT-O procedure with a 92% (70 of 76) cure rate and an 8% (6 of 76) improvement rate. No inefficient or aggravated cases occurred in both groups. The success rates between groups had no significant statistic difference (p > 0.05). The operative time, blood loss, hospital stay, and medical cost were significantly lower in the test group (p < 0.01); the increases in Quality-of-life scores were comparable between groups. CONCLUSIONS: The modified transobturator vaginal tape procedure is an efficacious and economic surgical treatment for female SUI.

Magnetic resonance imaging for secondary assessment of breast density in a high-risk cohort.

A quantitative measure of three-dimensional breast density derived from noncontrast magnetic resonance imaging (MRI) was investigated in 35 women at high-risk for breast cancer. A semiautomatic segmentation tool was used to quantify the total volume of the breast and to separate volumes of fibroglandular and adipose tissue in noncontrast MRI data. The MRI density measure was defined as the ratio of breast fibroglandular volume over total volume of the breast. The overall correlation between MRI and mammographic density measures was R(2)=.67. However the MRI/mammography density correlation was higher in patients with lower breast density (R(2)=.73) than in patients with higher breast density (R(2)=.26). Women with mammographic density higher than 25% exhibited very different magnetic resonance density measures spread over a broad range of values. These results suggest that MRI may provide a volumetric measure more representative of breast composition than mammography, particularly in groups of women with dense breasts. Magnetic resonance imaging density could potentially be quantified and used for a better assessment of breast cancer risk in these populations.

Breast density assessment in adolescent girls using dual-energy X-ray absorptiometry: a feasibility study.

Breast density, the radiographically opaque fraction of the breast in a mammogram, is one of the strongest biomarkers of breast cancer risk. However, younger populations do not typically have mammograms due to radiation concerns. This study explored a commercially available dual-energy X-ray absorptiometer (DXA) system as a low-dose method to measure breast fibroglandular density in adolescent girls. Eighteen girls (13-14 years old) indicated their breast development according to Tanner and underwent three dedicated DXA scans, two of their left and one of their right breasts. Total projected breast area was manually delineated on each image and percent fibroglandular volume density (%FGV), absolute fibroglandular volume (FGV), total breast area, and volume were computed. It was possible to image breasts representing all five Tanner stages; %FGV ranged from 31.9% to 92.2% with a mean of 71.1 +/- 14.8%, whereas FGV ranged from 80 to 270 cm(3) with a mean of 168 +/- 54 cm(3). Left and right breast %FGV were highly correlated (r(p) = 0.97, P < 0.0001) and of the same magnitude (P = 0.18). However, left total volume and FGV were larger than the right by 38 cm(3) (P = 0.04) and 19 cm(3) (P = 0.02), respectively. Total volume and FGV increased by Tanner stage, whereas %FGV did not. Our method had excellent precision for %FGV and moderate precision for FGV (root mean square SDs of 2.4% and 16.6 cm(3)). These pilot data indicate that dedicated DXA breast scans may be useful in studies exploring breast density in girls.

[Fluorescence fluctuation spectroscopy with strong background fluorescence--a Monte Carlo approach].

Fluorescence fluctuation spectroscopy is a method in which fluorescence fluctuations arising from a very small sample volume are analysed to obtain brightness, diffusion coefficient and concentration of particles. Using Monte Carlo simulation, the influences of background autofluorescence and noises on fluorescence fluctuation spectroscopy are studied. Results show that a two-component photon counting histogram can effectively remove the effects due to background autofluorescence from low brightness and high concentration components and uniform noise. The result will help to bring applications of fluorescence fluctuation spectroscopy to intracellular environment.

Quantitative and qualitative assessment of closed fracture healing using computed tomography and conventional radiography.

RATIONALE AND OBJECTIVES: Development of new agents to induce fracture healing requires more sensitive methods to detect early changes in fracture repair. The aims of this study were to determine quantitative and qualitative features of fracture healing using volumetric computed tomography (CT) and to compare them with conventional radiography during the weeks following uncomplicated fractures of the appendicular skeleton. MATERIALS AND METHODS: 39 otherwise healthy men and women with acute, closed fractures of the distal radius, tibial and/or fibular malleoli, or tibial shaft, were enrolled and underwent CT and X-ray imaging at 1, 2, 4, 8, 12, and 16 (tibial shaft only) weeks post fracture. Qualitative assessment included fracture line/margins, fracture gap, external callus appearance, callus-to-cortex ratio, bridging, and radiologic union. Quantitative assessment of CT density changes (Hounsfield units [HU]) in the fracture gap was performed in a subset of 8 fracture patients using MEDx multimodality image analysis software (Sterling,VA). The analysis was performed by drawing free form regions of interest (ROI) covering the fracture gap on baseline (week 1) images and by automated registration of the follow-up images to the baseline co-ordinate system. RESULTS: The mean time to achieve radiologic union on CT was slightly shorter than on X-rays for radial and tibial shaft fractures (7.3 vs. 8.0 weeks, P = .1). Blurring of the fracture margins and reactive sclerosis were the earliest signs of healing in both modalities. External callus formation was evident in 11 cases and was detected earlier with CT technique. Overall, CT images allowed for more complete and detailed visualization of healing compared with conventional X-rays, which were limited by cast and fixation hardware superimposition, especially in subjects with malleolar and distal radial fractures. Quantitative evaluation showed good intraobserver and interobserver reproducibility and a statistically significant correlation to qualitative changes. CONCLUSION: Our methods of fracture healing assessment are reliable tools that are able to detect early changes in normal bone healing and may serve as useful additions to subjective image analysis in monitoring fracture healing in clinical trials. CT shows some advantages over conventional X-rays in evaluation of early fracture healing.