Risk factor analysis and nomogram construction in patients with distant metastatic prostate cancer at different PSA levels: a study based on the SEER database.

OBJECTIVE: Prostate cancer (PCa) is the most common malignant tumor in the male genitourinary system. Once PCa has metastasized, it is very difficult to cure. The purpose of this study was to investigate the prognostic risk factor analysis of patients with different prostate-specific antigen (PSA) levels in distant metastatic PCa. At the same time, we construct effective models for predicting the survival rate of prostate cancer patients. PATIENTS AND METHODS: Data on prostate cancer patients with the presence of distant metastases were obtained from the Surveillance, Epidemiology, and End Results (SEER) database. PCa patients with distant metastases were categorized into two groups based on PSA levels, one with PSA <20 ng/mL and the other with PSA ≥20 ng/mL. Univariate and multivariate COX regression analyses were used to identify independent factors affecting the prognosis of the patients. A nomogram was constructed using the independent prognostic factors, and the results were evaluated using calibration curves, timeROC curves, and Kaplan-Meier curves. RESULTS: In the PSA <20 ng/mL group, there were a total of 1,832 patients. COX regression analysis showed that age, marital status, N stage, grade, Gleason score, and medical household income inflation were independent prognostic factors for overall survival (OS) in patients. In addition, we found that age, marital status, N stage, bone metastasis, grade, and Gleason score were independent prognostic factors for cancer-specific survival (CSS) in patients. In the PSA ≥20 ng/mL group, there were a total of 5,314 patients. It was found that age, ethnicity, marital status, bone metastasis, first malignant primary indicator, grade, Gleason score, and medical household income inflation were patients' independent prognostic factors for OS. For CSS, we found that age, ethnicity, marital status, T stage, radiotherapy, bone metastasis, Gleason score, and Median household income inflation were independent prognostic factors. Constructing a nomogram can accurately predict the prognosis of this group of patients. CONCLUSIONS: We found different independent prognostic factors for different PSA levels in patients with distant metastatic PCa. A new nomogram was constructed to predict OS and CSS in patients, which helps in clinical-assisted decision-making.

A comprehensive analysis of essential meiotic endonuclease 1 to prognosis and immune infiltration in kidney renal clear cell carcinoma.

OBJECTIVE: Clear cell renal cell carcinoma (ccRCC) is the most common type of cancer, and its molecular pathogenesis is unclear. In this study, we investigated the prognostic value of essential meiotic endonuclease 1 (EME1) in kidney renal clear cell carcinoma (KIRC). MATERIALS AND METHODS: We downloaded the RNA-Seq expression of 526 KIRC tissues and 72 normal tissues from the TCGA database and the corresponding clinical data. The gene expression profiles associated with four clear cell renal cell carcinomas were downloaded from the GEO database for analysis. The expression of EME1 in clear renal cell carcinoma and its correlation with the clinical baseline data were analyzed. Kaplan-Meier survival curve analysis was performed to assess the relationship between EME1 and patient survival. Enrichment analysis was performed to elucidate the possible functions of EME1. We also analyzed the relationship between the EME1 expression and immune infiltration through TIMER2.0 and TISIDB online databases as well as the relationship between EME1 and common immune checkpoints. RESULTS: EME1 was identified as a risk factor for overall survival in clear cell renal cell carcinoma with a hazard ratio of 3.201 (95% confidence interval: 2.430-4.215; p < 0.001). EME1 was highly expressed in KIRC compared to that in normal tissues (p < 0.001) and in the worse TNM stages and late stages (stage 3/4) (p < 0.001). High EME1 expression was strongly associated with the advanced T stage (p = 0.003), advanced N stage (p = 0.002), and advanced M stage (p = 0.006). Research data on KIRC were simultaneously collected and analyzed from the GEO database, including GSE40435, GSE53000, GSE68417, and GSE53757. EME1 predicted the survival status in KIRC patients (AUC = 0.62). We further established a nomogram including the correlation between the high and low EME1 expression, and EME1 was found to contribute to the prediction of the probability of patient survival with a c-index = 0.796. Kaplan-Meier analysis revealed a lower likelihood of survival with a high EME1 expression (p < 0.001). In addition, further bioinformatics analysis suggested that EME1 may be associated with the extent of immune infiltration in KIRC. CONCLUSIONS: An increased expression of EME1 in KIRC is thus associated with advanced clinicopathological features, possibly acting as a potential biomarker of poor prognosis in KIRC.

Evaluating the efficacy of recombinant human bone morphogenic protein-2 in the treatment of alveolar clefts with autologous bone grafting using computer-aided engineering techniques.

Recent studies have indicated the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) to be a viable adjunctive to alveolar cleft reconstruction owing to its osteoinductive capacity. This study aimed to evaluate the efficacy of rhBMP-2 in the treatment of alveolar cleft with autologous bone grafts by precise volumetric analysis. Twenty-six patients (aged 8-14) with unilateral alveolar clefts were enrolled in this comparative study. Patients were divided into two groups: the iliac crest bone graft (ICBG) was placed at the side of the cleft in the control group (ICBG group), and rhBMP-2 was mixed with the ICBG in the rhBMP-2 group (BMP group). Helical computed tomographic images were obtained preoperatively and 12 months postoperatively. The datasets were reconstructed as three-dimensional (3D) images using Mimics software and processed using Geomagic Wrap. The newly formed bone of the alveolar cleft was segmented by identifying the differences between preoperative and postoperative 3D images. In the ICBG group, the volume of newly formed bone ranged from 0.25 to 0.88 cm3, and the mean (SD) bone formation percentage was 42.01% (15.57%). In the BMP group, the volume of newly formed bone ranged from 0.34 to 1.09 cm3, and the bone formation mean (SD) percentage was 55.79% (11.84%). There was a statistically significant difference between the two groups in terms of the postoperative percentage of bone formation (p = 0.022). Thus, rhBMP-2 combined with an autologous bone graft is a promising technique to improve the results of secondary alveolar bone grafting.

IGF-1 affects the development of myocarditis in LDL-R knockout mice by inhibiting peritoneal infiltration of macrophages.

OBJECTIVE: Infiltration of the inflammatory cells, such as macrophages and myocardial necrosis, are involved in myocarditis. Insulin-like growth factor (IGF-1) exerts a variety of biological effects. However, the role of IGF-1 in myocarditis remains unclear. PATIENTS AND METHODS: LDL-R knockout mice were randomly divided into the control group, myocarditis group, and IGF-1 siRNA group. Real Time-Polymerase Chain Reaction (PCR) and Western blot were used to measure IGF-1 expression in myocardial tissue. The myocardial tissue changes were analyzed by HE staining. The total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) in each group were detected. Flow cytometry was used to analyze the number of macrophages. The secretion of TNF-α and INF-γ and macrophage migration inhibitory factor (MIF) were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: Compared with the control group, IGF-1 expression, TC, and LDL in myocarditis group was significantly increased, along with decreased heart rate (HR), left ventricular end-systolic diameter (LVEDs), left ventricular end-diastolic diameter (LVEDd), and left ventricular mass index (LVMI). In addition, inflammatory cell infiltration, fibrosis, and macrophages number in the peritoneum were increased. Moreover, the secretion of TNF-α, INF-γ, and MIF was also significantly increased (p<0.05). However, IGF-1 siRNA treatment inhibited IGF-1 expression and reversed the changes in the myocarditis group with statistically significant differences compared with the myocarditis group (p<0.05). CONCLUSIONS: IGF-1 expression is increased in myocarditis. The downregulation of IGF-1 expression inhibits macrophages infiltration, reduces the expression of MIF and inflammatory factors, and improves myocarditis injury.

[Value of European Organisation for Research and Treatment of Cancer score system for predication of immediate postoperative intravesical instillation of pirarubicin after transurethral resection of non-muscle invasive bladder cancer].

Objective: To assess value of immediate postoperative intravesical instillation of pirarubicin after transurethral resection (TURBT)of non-muscle invasive bladder cancer. Methods: 484 patients diagnosed with non-muscle-invasive bladder cancer admitted to the Second Affiliated Hospital of Kunming Medical University were divided into two groups after transurethral resection of bladder tumor. 285 patients received postoperative intravesical instillation of pirarubicin within 6 hours after the surgery, 199 patients received first instillation of pirarubicin at 10 days after the surgery, after that, all the patients received routine bladder perfusion chemotherapy. Patients who received intravesical instillation of pirarubicin within 6 hours were defined as immediate intravesical instillation group and the other patients as the control group. Based on the European Organisation for Research and Treatment of Cancer risk tables, scores of recurrence and progression of patients were calculated and then stratified into risk groups accordingly. Recurrence and progression rates of the immediate intravesical instillation group were analyzed and then compared with the corresponding reference of the risk tables. Results: The 1-year and 5-year recurrence rate of patients with EORTC table scoring 0 in the immediate intravesical instillation group were significantly lower than that of the EORTC reference group (5.3% and 14.0% vs 15.0% and 31.0%, P<0.05). 1-year recurrence free rate between the immediate intravesical instillation group and the control group in patients scoring 1-4 was significantly different (81.3% vs 76.7%, P=0.014). However, 1-year recurrence free rate of the immediate intravesical instillation group was comparable with that of the control group in patients scoring 5-9, 10-17(P>0.05), which is quite close to the EORTC reference. The probability rates of 1-year and 5-year progression of the 285 patients who received immediate intravesical instillation group did not show significant difference with the EORTC reference. On multivariate analysis, previous recurrence, tumor grade G2-3, tumor multiplicity, delay of immediate intravesical instillation were independent risk factors of recurrence(P<0.05). Conclusions: With the help of EORTC recurrence risk table stratifying the patients into different risk groups, our study showed that delay of immediate postoperative intravesical instillation of chemotherapy after TURBT was an independent risk factor of post-surgery recurrence of tumor. Moreover, patients with EORTC scoring 1-4 might obtain greatest benefits.

MiR-130b functions as a tumor promoter in glioma via regulation of ERK/MAPK pathway.

OBJECTIVE: To investigate the miR-130b expression in patients with glioma and to analyze its role and underlying molecular mechanism on the carcinogenesis. PATIENTS AND METHODS: The expression levels of miR-130b were detected with quantitative Real-time PCR. The relationship between miR-130b expression and clinicopathologic characteristics were analyzed. MiR-130b inhibitor was transfected into glioma cell lines to investigate its role in HCC. MTT assays were conducted to explore the impact of miR-130b down-expression on the proliferation of human glioma cells. Cell cycle and cell apoptosis assays were performed using flow cytometry. Levels of ERK/MAPK pathway related proteins were evaluated by Western blotting. Data were analyzed using the 2-ΔΔCT method through student's t-test via the GraphPad Prism software (La Jolla, CA, USA). RESULTS: The expression of miR-130b was markedly upregulated in glioma cell lines and tissues, and high miR-130b expression was significantly associated with advanced WHO grade (p = 0.022) and low Karnofsky performance score (p = 0.001). In addition, downregulation of miR-130b inhibited the proliferation of glioma cells and induced cell-cycle arrest and cells apoptosis in vivo. Importantly, ERK/MAPK pathway was found to be inactivated in the glioma cell lines after miR-130b knockout experiment. CONCLUSIONS: The current data indicated that miR-130b may play a critical role in the progression of glioma via ERK/MAPK signaling cascades, suggesting that it may be a useful therapeutic agent in glioma patients.

Therapeutic efficacy of atypical antipsychotic drugs by targeting multiple stress-related metabolic pathways.

Schizophrenia (SZ) is considered to be a multifactorial brain disorder with defects involving many biochemical pathways. Patients with SZ show variable responses to current pharmacological treatments of SZ because of the heterogeneity of this disorder. Stress has a significant role in the pathophysiological pathways and therapeutic responses of SZ. Atypical antipsychotic drugs (AAPDs) can modulate the stress response of the hypothalamic-pituitary-adrenal (HPA) axis and exert therapeutic effects on stress by targeting the prefrontal cortex (PFC) and hippocampus. To evaluate the effects of AAPDs (such as clozapine, risperidone and aripiprazole) on stress, we compared neurochemical profile variations in the PFC and hippocampus between rat models of chronic unpredictable mild stress (CUMS) for HPA axis activation and of long-term dexamethasone exposure (LTDE) for HPA axis inhibition, using an ultraperformance liquid chromatography-mass spectrometry (UPLC-MS/MS)-based metabolomic approach and a multicriteria assessment. We identified a number of stress-induced biomarkers comprising creatine, choline, inosine, hypoxanthine, uric acid, allantoic acid, lysophosphatidylcholines (LysoPCs), phosphatidylethanolamines (PEs), corticosterone and progesterone. Specifically, pathway enrichment and correlation analyses suggested that stress induces oxidative damage by disturbing the creatine-phosphocreatine circuit and purine pathway, leading to excessive membrane breakdown. Moreover, our data suggested that the AAPDs tested partially restore stress-induced deficits by increasing the levels of creatine, progesterone and PEs. Thus, the present findings provide a theoretical basis for the hypothesis that a combined therapy using adenosine triphosphate fuel, antioxidants and omega-3 fatty acids as supplements may have synergistic effects on the therapeutic outcome following AAPD treatment.

A potential mechanism underlying atypical antipsychotics-induced lipid disturbances.

Previous findings suggested that a four-protein complex, including sterol-regulatory element-binding protein (SREBP), SREBP-cleavage-activating protein (SCAP), insulin-induced gene (INSIG) and progesterone receptor membrane component 1 (PGRMC1), within the endoplasmic reticulum appears to be an important regulator responsible for atypical antipsychotic drug (AAPD)-induced lipid disturbances. In the present study, effects of typical antipsychotic drug and AAPDs as well as treatment outcome of steroid antagonist mifepristone (MIF) on the PGRMC1/INSIG/SCAP/SREBP pathway were investigated in rat liver using real-time quantitative polymerase chain reaction (qPCR) and western blot analysis. In addition, serum triacylglycerol, total cholesterol, free fatty acids and various hormones including progesterone, corticosterone and insulin were measured simultaneously. Following treatment with clozapine or risperidone, both lipogenesis and cholesterogenesis were enhanced via inhibition of PGRMC1/INSIG-2 and activation of SCAP/SREBP expressions. Such metabolic disturbances, however, were not demonstrated in rats treated with aripiprazole (ARI) or haloperidol (HAL). Moreover, the add-on treatment of MIF was effective in reversing the AAPD-induced lipid disturbances by upregulating the expression of PGRMC1/INSIG-2 and subsequent downregulation of SCAP/SREBP. Taken together, our findings suggest that disturbances in lipid metabolism can occur at an early stage of AAPD treatment before the presence of weight gain. Such metabolic defects can be modified by an add-on treatment of steroid antagonist MIF enhancing the PGRMC1 pathway. Thus, it is likely that PGRMC1/INSIG-2 signaling may be a therapeutic target for AAPD-induced weight gain.

A fluorescent probe for H2S in vivo with fast response and high sensitivity.

In this work, we design and synthesize a new near-infrared (NIR) ratiometric fluorescent probe FD-H2S for the highly sensitive (DL 68.2 nM) detection of H2S with fast response (15 s), large emission shift (220 nm) and excellent enhancement (168-fold in ratiometric value). The probe could be applied for monitoring and imaging of exogenous or endogenous H2S in live MCF-7 cells and in live mice with the fastest response.

Effects of rhM-CSF expressed in silkworm on cytokine productions and membrane molecule expressions of human monocytes.

AIM: To study the effects of recombinant human macrophage colony-stimulating factor (rhM-CSF) expressed in silkworm on cytokine productions and membrane molecule expressions of monocytes. METHODS: The rhM-CSF was added to the human peripheral blood monocyte cultures and 3 d later, the culture supernatants and cells were collected, respectively. TNF-alpha, IL-6, IL-8, and IFN-alpha levels in the supernatants were detected by biological activity test or ELISA and expressions of CD11b, CD16, HLA I, and HLA II on the cellular surface were examined by the method of alkaline phosphatase anti-alkaline phosphatase complex (APAAP). RESULTS: The rhM-CSF promoted TNF-alpha, IL-6, and IL-8 inductions of monocytes and increased the percentages of CD11b, CD16, HLA I, and HLA II molecule expression on monocytes. CONCLUSION: The rhM-CSF plays a role in monocyte function up-regulation and has a certain practical value in immunological therapy.

[Effect of corticotrophin on formaldehyde-induced somatostatin of spinal cord in rats].

AIM: To study the effect of corticotrophin (Cor) on somatostatin (Som) and its synthesis in spinal dorsal horn induced by formaldehyde in rats. METHODS: Using double immunohistochemical stainings, and in situ hybridization. RESULTS: Two hours after s.c. formaldehyde (5%, 200 microL) in one hindpaw of rats, the neurons of c-fos-like immunoreactivity (FLI), somatostatin-like immunoreactivity (Som-LI), Som-LI/FLI, and perprosomatostatin mRNA (PPS-mRNA) in ipsilateral spinal dorsal horn were increased obviously, as compared with the control group. The FLI and Som-LI of spinal cord were not changed by i.p. Cor. Cor (25 or 12.5 U.kg-1, i.p.) inhibited the formaldehyde-evoked FLI, Som-LI, Som-LI/FLI, and PPS-mRNA of spinal cord in a dose-dependent manner. The decrease of c-fos or Som level due to i.p. Cor in rats of chronic pain was prevented by raphe nuclei injected cyproheptadine, but not by bicuculline, naloxone, or phentolamin injected to raphe nuclei. CONCLUSION: The formaldehyde-evoked c-fos expression, Som, and Som synthesis of spinal cord were suppressed by Cor through the serotonin receptor of raphe nuclei.

Intrathecal injection of corticotropin inhibited nitric-oxide synthase-positive neuron increase in rat spinal cord after formalin-induced hyperalgesia.

AIM: To study the effects of corticotropin (Cor) on formalin-induced hyperalgesia and the change of nitric-oxide synthase (NOS)-positive neurons in spinal dorsal horn in rats. METHODS: Measurement of pain intensity rating (PIR), NADPH-d histochemistry, and Fos immunohistochemistry were adopted. RESULTS: The increases of NOS-positive neurons, Fos, NOS/Fos double labelling neurons of the spinal dorsal horn and the PIR after formalin injection were markedly inhibited by intrathecal injecting (ith) Cor (0.5-1.5 U), which were obviously attenuated by L-arginine (Arg, 5-15 nmol, ith), the substrate of NOS. CONCLUSION: Cor inhibits formalin-induced hyperalgesia by the decrease of NOS-positive neurons in the spinal dorsal horn of rats.

[Effect of ACTH on the expression of somatostatin and c-fos in the spinal cord and formalin evoked pain response].

In the present study, the effect of ACTH on the expression of somatostatin and c-fos in the spinal cord and formalin induced pain responses in rats were studied using immunohistochemistry and in situ hybridization. The results showed that subcutaneous injection of formalin in the right hindpaw increased c-fos-like immunoreactivity (FLI), somatostatin-like immunoreactivity (Som-LI), Som-LI/FLI and perprosomatostatin mRNA (PPS-mRNA) in neurones of right spinal dorsal horn and significantly enhanced pain intensity rating. ACTH decreased the FLI,Som-LI, Som-LI/FLI and PPS-mRNA levels of the spinal cord evoked by formalin. The decrease of c-fos or Som level due to intrathecal injection of ACTH in rats with chronic pain was prevented by injection of cyproheptadine, but not by bicuculline and naloxone. The results indicate that the serotonin receptor may be involved in ACTH induced analgesia.

Effects of intra-hippocampal injection of interleukin-2 on pain threshold and formaldehyde-induced substance P-like immunoreactivity in periaqueductal gray and spinal cord.

AIM: To study the effects of intra-hippocampal injection of interleukin-2 (IL-2) on the substance P-like immunoreactivity (SP-LI) in both periaqueductal gray (PAG) and spinal cord, and on pain threshold in rats. METHODS: Immunohistochemistry technique was used and the paw withdrawal threshold to radiant heat was measured. RESULTS: Microinjection of hIL-2 480 U in hippocampus (Hip) increased the pain threshold (93% +/- 57%, P < 0.01). Injection of formaldehyde (For) in one hindpaw decreased SP-LI neuron number on both sides of PAG (2.9 +/- 2.8 vs 22.1 +/- 0.7, 12.3 +/- 2.0 vs 22.4 +/- 1.0, P < 0.01) and increased SP-LI in ipsilateral spinal cord (0.836 +/- 0.015 vs 0.59 +/- 0.09, P < 0.01). Microinjection of hIL-2 480 U in Hip inhibited the effects of For on the SP-LI on both sides of the PAG (11.3 +/- 2.3 vs 2.9 +/- 2.8, 16.9 +/- 3.4 vs 12.3 +/- 2.0, P < 0.05) and spinal cord (0.71 +/- 0.03 vs 0.836 +/- 0.015, P < 0.01). The combination of intraperitoneal injection of corticotropin and intra-hippocampal injection of IL-2 increased the number of SP-LI neurons in PAG furtherly as compared with IL-2 240 U alone (13.6 +/- 3.6 vs 7.6 +/- 4.3, P < 0.05). CONCLUSION: The analgesic effects of intra-hippocampal injection of IL-2 are mediated, possibly, via the increased of SP in PAG and the decrease of SP in the spinal cord. There is a synergetic relation between IL-2 and corticotropin.

[Effect of corticotropin on formalin-evoked c-fos expression of spinal cord and receptors analysis in rat].

AIM: To study the effect of corticotropin (Cor) on c-fos expression induced by formalin in spinal cord of rat and the role of receptors. METHODS: Using immunohistochemistry and adrenalectomy. RESULTS: Cor inhibited the formalin-evoked c-fos expression in rat spinal cord in a dose-dependent manner. No obvious effect was seen by i.p. Cor 10 U.kg-1, but 25 U.kg-1 reduced the evoked c-fos expression, that was blocked by phentolamine, naloxone, or verapamil, but not much changed by adrenalectomy. CONCLUSION: The formalin-evoked c-fos expression of rat spinal cord was suppressed by Cor through the alpha-adrenergic receptors, opiate receptors and calcium, but no relation to adrenal glands.

[Somatostatin and electroacupuncture inhibited c-fos expression in spinal cord of arthritic rats].

AIM: To observer the effect of intrathecal injection of somatostatin (Som) associated with electroacupuncture (EA) at "Jiaji" points on c-fos protein expression of spinal cord in pain rats. METHODS: Rats with adjuvant arthritis were used as pain model and the c-fos-like immunoreactivity (FLI) was detected by immunohistochemistry. RESULTS: The c-fos protein expression induced by arthritis were found in all of the I-X laminae of ipsilateral spinal cord of rats, and most of the labeled cells were located in the laminae I-II and V-VI. Som and EA suppressed the c-fos expression and the lessening of FLI cells in the spinal cord. CONCLUSION: Pathological pain following arthritis activated pain sensitive neurons (PSN) and evoked c-fos expression in spinal cord, Som and EA suppressed activities of these PSN, producing the effect of analgesia.

Tree structured wavelet transform segmentation of microcalcifications in digital mammography.

A novel multistage algorithm is proposed for the automatic segmentation of microcalcification clusters (MCCs) in digital mammography. First, a previously reported tree structured nonlinear filter is proposed for suppressing image noise, while preserving image details, to potentially reduce the false positive (FP) detection rate for MCCs. Second, a tree structured wavelet transform (TSWT) is applied to the images for microcalcification segmentation. The TSWT employs quadrature mirror filters as basic subunits for both multiresolution decomposition and reconstruction processes, where selective reconstruction of subimages is used to segment MCCs. Third, automatic linear scaling is then used to display the image of the segmented MCCs on a computer monitor for interpretation. The proposed algorithms were applied to an image database of 100 single view mammograms at a resolution of 105 microns and 12 bits deep (4096 gray levels). The database contained 50 cases of biopsy proven malignant MCCs, 8 benign cases, and 42 normal cases. The measured sensitivity (true positive detection rate) was 94% with a low FP detection rate of 1.6 MCCs/image. The image details of the segmented MCCs were reasonably well preserved, for microcalcification of less than 500 microns, with good delineation of the extent of the microcalcification clusters for each case based on visual criteria.

Markov random field for tumor detection in digital mammography.

A technique is proposed for the detection of tumors in digital mammography. Detection is performed in two steps: segmentation and classification. In segmentation, regions of interest are first extracted from the images by adaptive thresholding. A further reliable segmentation is achieved by a modified Markov random field (MRF) model-based method. In classification, the MRF segmented regions are classified into suspicious and normal by a fuzzy binary decision tree based on a series of radiographic, density-related features. A set of normal (50) and abnormal (45) screen/film mammograms were tested. The latter contained 48 biopsy proven, malignant masses of various types and subtlety. The detection accuracy of the algorithm was evaluated by means of a free response receiver operating characteristic curve which shows the relationship between the detection of true positive masses and the number of false positive alarms per image. The results indicated that a 90% sensitivity can be achieved in the detection of different types of masses at the expense of two falsely detected signals per image. The algorithm was notably successful in the detection of minimal cancers manifested by masses

Digital mammography: M-channel quadrature mirror filters (QMFs) for microcalcification extraction.

Multiresolution methods are reported for feature extraction in breast cancer screening using digital mammography. The initial application is directed at the detection of microcalcification clusters (MCCs). Quadrature mirror filter (QMF) banks, using both two and three channel are proposed for the first time for both multiresolution decomposition and reconstruction. These filters are specifically tailored for automatic extraction of MCCs. The QMF multiresolution methods are compared to two channel tree structured wavelet transforms (TSWTs) methods previously reported. The QMF filters are preceded by an advanced tree structured nonlinear filter for noise suppression, prior to feature extraction, in order to minimize the false positive (FP) detection rate in digital mammography. The relative performance of these methods were evaluated using both simulated images and fifteen representative digitized mammograms containing biopsy proven microcalcification clusters. Similar high sensitivity (true positive (TP) detection rate (100%) and high specificity (0.6 average false positive (FP) MCC's/image) were observed, substantially better than more traditional approaches using single scale filters. The three channel QMF method, however, demonstrated better detail preservation of MCC's extracted compared to the two channel method. Detail preservation is important for the characterization of MCC's or individual microcalcifications in cancer screening.

Tree-structured non-linear filter and wavelet transform for microcalcification segmentation in digital mammography.

A novel algorithm was developed for computer aided diagnosis of microcalcification clusters in digital mammography. The method includes: (a) tree-structured central weighted median filters with variable shape windowing to suppress image noise but preserve image details; (b) a quasi range dispersion edge detector to increase edge contrast and definition; and (c) tree-structured wavelets for calcification segmentation. The preliminary evaluation of the method on nine mammograms showed that 100% sensitivity can be achieved at the expense of four false positive clusters per image. Research is ongoing for further optimization of the algorithm to reduce the number of false alarms and establish its clinical value.