Wavelet-based compression of medical images: filter-bank selection and evaluation

Wavelet-based image coding algorithms (lossy and lossless) use a fixed perfect reconstruction filter-bank built into the algorithm for coding and decoding of images. However, no systematic study has been performed to evaluate the coding performance of wavelet filters on medical images. We evaluated the best types of filters suitable for medical images in providing low bit rate and low computational complexity. In this study a variety of wavelet filters are used to compress and decompress computed tomography (CT) brain and abdomen images. We applied two-dimensional wavelet decomposition, quantization and reconstruction using several families of filter banks to a set of CT images. Discreet Wavelet Transform (DWT), which provides efficient framework of multi-resolution frequency was used. Compression was accomplished by applying threshold values to the wavelet coefficients. The statistical indices such as mean square error (MSE), maximum absolute error (MAE) and peak signal-to-noise ratio (PSNR) were used to quantify the effect of wavelet compression of selected images. The code was written using the wavelet and image processing toolbox of the MATLAB (version 6.1). This results show that no specific wavelet filter performs uniformly better than others except for the case of Daubechies and bi-orthogonal filters which are the best among all. MAE values achieved by these filters were 5 x 10(-14) to 12 x 10(-14) for both CT brain and abdomen images at different decomposition levels. This indicated that using these filters a very small error (approximately 7 x 10(-14)) can be achieved between original and the filtered image. The PSNR values obtained were higher for the brain than the abdomen images. For both the lossy and lossless compression, the 'most appropriate' wavelet filter should be chosen adaptively depending on the statistical properties of the image being coded to achieve higher compression ratio.     

A comparative study of three warming interventions to determine the most effective in maintaining perioperative normothermia

Perioperative hypothermia poses a challenge because of its deleterious effects on patient recovery. The current practice of applying two cotton blankets on patients during surgery is thought to be less ideal than using reflective insulation or forced-air warming. We studied 300 patients who underwent unilateral total knee replacement and were randomized equally to three groups: (a) the two-cotton-blanket group, (b) the one-reflective-blanket with one-cotton-blanket group, and (c) the forced-air-warming with one-cotton-blanket group. Tympanic temperature readings were taken before surgery in the induction room, on arrival at the recovery room, and at 10-min intervals until discharge from the recovery room. On arrival at the recovery room, the forced-air-warming group had significantly higher temperatures (adjusted for sex, age, and patient's induction room temperature) of 0.577 degrees C +/- 0.079 degrees C (95% confidence interval [CI], 0.427-0.726; P < 0.001) and 0.510 degrees C +/- 0.08 degrees C (95% CI, 0.349-0.672; P < 0.001) more than the reflective-blanket and two-cot-ton-blanket groups, respectively. The forced-air-warming group took a significantly (P < 0.001) shorter time of 18.75 min (95% CI, 13.88-23.62) to achieve a temperature of 36.5 degrees C in the recovery room as compared with 41.78 min (95% CI, 36.86-46.58) and 36.43 min (95% CI, 31.23-41.62) for the reflective-blanket and two-cotton-blanket groups, respectively. The reflective technology was less effective than using two cotton blankets, and the forced-air warming was most efficient in maintaining perioperative normothermia. IMPLICATIONS: Perioperative hypothermia has deleterious effects on patient recovery. We found in patients having knee surgery that reflective technology was less effective than using two cotton blankets, whereas active surface warming with the forced-air method was most effective in maintaining normothermia.     

Contrast material extravasation on contrast-enhanced helical computed tomographic scan of blunt abdominal trauma: its significance on the choice,time, and outcome of treatment

BACKGROUND: Contrast-enhanced helical computed tomographic (CT) scan of blunt abdominal trauma is valuable for detecting contrast material extravasation (CME). The aims of this study were to determine its significance and investigate factors associated with the choice, time, and outcome of management. METHODS: CT scans of 32 consecutive trauma patients who had CME were reviewed for the sources of CME, types of CME, flat inferior vena cava, and multiple abdominal injuries. The medical records were reviewed for demographics, systolic blood pressure, Injury Severity Score (ISS), choice of management, time interval between CT scan and intervention, and outcome of intervention. RESULTS: Systolic blood pressure < 100 mm Hg was the most important factor (p = 0.0064) that failed observational therapy. When proceeding to intervention treatment, patients with a flat inferior vena cava (1.6 +/- 1.1 hours) had a significantly shorter time interval between CT scan examination and intervention when compared with those with a normal cava (10.9 +/- 16.0 hours) ( p= 0.0124). The mortality rate after intervention treatment was 18.8%. High ISS, uncontained CME in the extraperitoneum, and multiple abdominal injuries were important risk factors. After adjusted for ISS and multiple abdominal injuries, the risk of dying from extraperitoneal CME remained significant when compared with intraperitoneal CME (adjusted odds ratio, 82.26; 95% confidence interval, 1.06-6,363.17). CONCLUSION: Termination of observational therapy was appropriate for trauma patients who had CME and systolic blood pressure < 100 mm Hg. The coexistence of a flat inferior vena cava and CME was associated with early intervention treatment. Despite early intervention, the mortality rate was 18.8%. High ISS and multiple abdominal injuries were important factors, but the risk of dying from uncontained extraperitoneal CME was 82 times the risk of dying from intraperitoneal CME.     

Histopathological and CT features of pulmonary sclerosing haemangiomas

AIM: To demonstrate the computed tomography (CT) features of pulmonary sclerosing haemangiomas. MATERIALS AND METHODS: Six pathologically proven sclerosing haemangiomas were included in this retrospective review. Patients consisted of five women and one man aged 20-54 years (mean, 34.5 years). Their CT features were recorded according to enhancement patterns and the presence of a tail sign, prominent pulmonary artery sign, air-trapping sign, presence of calcification or cystic spaces, consolidation, and interstitial infiltration. The predominant composition of an individual sclerosing haemangioma was documented by means of microscopy. RESULTS: Inhomogeneous enhancement was frequently present and depended on the various compositions of the tumours, especially those in sclerotic and predominantly papillary predominant types. The presence of a tail sign, intra-tumoural cystic areas, and a prominent artery sign were the frequent features in our cases. CONCLUSION: Sclerosing haemangioma should be considered in young or middle-aged female patients whose CT images show them having an inhomogeneous enhancing soft tissue mass with a smooth outline and with above the aforementioned features.     

Bcl-2 and bax expression in advanced non-small cell lung cancer: lack of correlation with chemotherapy response or survival in patients treated with docetaxel plus vinorelbine

Surgical series of non-small cell lung cancer (NSCLC) pathologic samples have shown that the expression of the proteins bcl-2 and bax, which regulate cell death, may have prognostic implications. Laboratory data also suggests that these proteins may impact chemotherapy response. In order to determine the rate of bcl-2 and bax expression in advanced NSCLC and assess the impact on chemotherapy response and patient survival, we performed immunohistochemistry on biopsy samples from patients enrolled in a phase I/II trial of vinorelbine plus docetaxel. We chose to study the pathology of patients in this specific trial because both docetaxel and vinorelbine phosphorylate bcl-2 and we hypothesized that this mechanism may affect clinical outcome. The goal of this study was to determine the feasibility of this analysis, and to observe any differences in response rate or survival based on bcl-2 or bax staining results. Unstained slides from paraffin blocks were obtained for 31 patients (55%) on the phase I/II trial. The patient characteristics for this subgroup did not differ significantly from the entire cohort of patients on the trials. Bcl-2 staining was positive in 5/31 samples (16%, 95% CI 3-29%) and bax was positive in 19/28 samples (68%, 95% CI 51-85%). Bcl-2 and bax staining did not correlate with response (p = 0.65 and 1.00 respectively, Fisher's exact test), or survival (by Kaplan-Meier curves). In conclusion, bcl-2 and bax expression was similar in this population with advanced NSCLC to previously reported results for early stage disease, but did not predict response to vinorelbine plus docetaxel in this series.     

Inducible nitric oxide synthase and bcl-2 expression in nasopharyngeal cancer: correlation with outcome of patients after radiotherapy

PURPOSE: The expression of inducible nitric oxide synthase (iNOS) and bcl-2 proteins was evaluated and the prognostic significance determined in nasopharyngeal cancer (NPC) patients treated by radiotherapy. METHODS AND MATERIALS: Tissue sections from 55 patients with NPC were assessed for iNOS and bcl-2 protein expression by immunohistochemistry, immunoelectron microscopy, and in situ hybridization before treatment. The markers were correlated with apoptosis (detected by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay) and clinicopathologic parameters. RESULTS: All NPC sections exhibited positive iNOS and bcl-2 immunoreactivity, with a mean percentage of 6.24% +/- 0.58% and 17.09% +/- 2.48%, respectively. A significant positive correlation was observed between iNOS expression and the apoptotic index (p < 0.0001, Pearson's r = 0.8518), and bcl-2 expression correlated inversely with apoptosis (p = 0.0001; Pearson's r = -0.6170). A significant inverse correlation was found between iNOS and bcl-2 immunoreactivity (p < 0.0001, Pearson's r = -0.7144). Bcl-2 but not iNOS expression was associated with the stage of the tumor according to the criteria of the American Joint Committee on Cancer (1997) (p < 0.0001). Patients who had recurrence of the tumor and metastasis after radiotherapy had a lower expression of iNOS (p = 0.014 and p = 0.035, respectively), although overall survival was not significantly different statistically. Higher bcl-2 expression was also associated with local tumor recurrence (p = 0.005) but not with metastasis or overall survival. CONCLUSION: It appears that iNOS and bcl-2 expression may be potentially useful biomarkers for predicting the outcome of radiotherapy in NPC patients.     

Anti-Herpes simplex virus activity of Bidens pilosa and Houttuynia cordata

The present study evaluated the antiviral activity of Bidens pilosa L. var. minor (Blume) Sherff and Houttuynia cordata Thunb., using cytotoxicity test with XTT-based colorimetric assay. BCC-1/KMC cells were infected with herpes simplex virus (HSV) and then were cultured with hot water extract of B. pilosa (HWBP) or H. cordata (HWHC). Results showed that HWBP significantly inhibited the replication of HSV at a concentration of 100 microg/ml (11.9% for HSV-1, p < 0.01; 19.2% for HSV-2, p < 0.005), whereas HWHC had the same effect at a concentration of 250 microg/ml (10.2% for HSV-1, p < 0.05; 32.9% for HSV-2, p < 0.005). The ED50 of HSV type 1 (HSV-1) and HSV type 2 (HSV-2) for HWBP was 655.4 microg/ml and 960 microg/ml respectively, for HWHC it was 822.4 microg/ml and 362.5 microg/ml respectively. Both drugs had selective indexes above 1.04. H. cordata had better effect against HSV-2 than HSV-1, and had a low ED50 against HSV-2. We suggest that H. cordata might be a useful medicinal plant against infection of HSV-2.     

A survey exploring the educational needs of care practitioners in learning disability (LD) settings in relation to death,dying and people with learning disabilities

This paper presents the findings of a small scale pilot study which explored the educational base and needs of qualified care practitioners in Learning Disability (LD) settings in relation to death, dying and people with learning disabilities. Eighty questionnaires were sent to two NHS Trusts in the South of England. The response rate for the qualified care practitioners from Cherry Blossom (CB) was 100%, whereas for Greengages (GG), the response rate was only 25%. The response from the unqualified care practitioners was disappointingly low, hence we declared them null and void. The analysis of data highlighted major concerns: namely, a lack of consistent policy in the recording of death in residential homes for dying persons with LD; a lack of knowledge, particularly in psychosocial aspects and skills in care of dying persons. The majority of the qualified care practitioners surveyed highlighted the importance of communication with clients and their families. We recommend that communication and interpersonal skills in the care and management of the terminally ill persons with LD be the core component in the nursing curriculum which at present only indicates a trace of it. It is not made explicit that it is essential. This study supports the notion that issues of LD override and obscure physical illness. Our study also highlights ambiguity in the use of concepts and terminology, and demonstrates some limitations in our methodology. We propose that further research, using different methodological approaches, such as Ethnography, Ethnomethodology, or a combination of these, would be appropriate.     

An evidence-based specialist breast nurse role in practice: a multicentre implementation study

The objective of this study was to examine the feasibility, implementation, acceptability and impact of an evidence-based specialist breast care nurse (SBN) model of care in Australia. Primary data were collected from four diverse Australian breast cancer treatment centres over a 12-month period. The design was a multicentre demonstration project. Information about the provision of care and patient needs was collected through prospective logs. Structured interviews were conducted with women who received the SBN intervention ( N  = 167) and with a control group of women treated prior to the intervention period ( N  = 133). Health professionals ( N  = 47) were interviewed about their experience of the SBN. Almost all women had contact with an SBN at five scheduled consultations and 67% of women in the intervention group requested at least one additional consultation with the SBN. Women in the intervention group were more likely to receive hospital fact sheets and to be told about and participate in clinical trials. Ninety-eight per cent of women reported that the availability of an SBN would affect their choice of hospital, with 48% indicating that they would recommend only a hospital with a SBN available. Health professionals reported that SBNs improved continuity of care, information and support for the women, and resulted in more appropriate referrals and use of the time of other members of the team. In conclusion, the SBN model is feasible and acceptable within diverse Australian treatment centres; there is evidence that some aspects of care were improved by the SBN.