Comparison of standard image segmentation methods for segmentation of brain tumors from 2D MR images

In the analysis of medical images for computer-aided diagnosis and therapy, segmentation is often required as a preliminary step. Medical image segmentation is a complex and challenging task due to the complex nature of the images. The brain has a particularly complicated structure and its precise segmentation is very important for detecting tumors, edema, and necrotic tissues in order to prescribe appropriate therapy. Magnetic Resonance Imaging is an important diagnostic imaging technique utilized for early detection of abnormal changes in tissues and organs. It possesses good contrast resolution for different tissues and is, thus, preferred over Computerized Tomography for brain study. Therefore, the majority of research in medical image segmentation concerns MR images. As the core juncture of this research a set of MR images have been segmented using standard image segmentation techniques to isolate a brain tumor from the other regions of the brain. Subsequently the resultant images from the different segmentation techniques were compared with each other and analyzed by professional radiologists to find the segmentation technique which is the most accurate. Experimental results show that the Otsu’s thresholding method is the most suitable image segmentation method to segment a brain tumor from a Magnetic Resonance Image.

Genetic analysis of maize streak virus isolates from Uganda reveals widespread distribution of a recombinant variant

Maize streak virus (MSV) contributes significantly to the problem of extremely low African maize yields. Whilst a diverse range of MSV and MSV-like viruses are endemic in sub-Saharan Africa and neighbouring islands, only a single group of maize-adapted variants - MSV subtypes A1 -A6 - causes severe enough disease in maize to influence yields substantially. In order to assist in designing effective strategies to control MSV in maize, a large survey covering 155 locations was conducted to assess the diversity, distribution and genetic characteristics of the Ugandan MSV-A population. PCR-restriction fragment-length polymorphism analyses of 391 virus isolates identified 49 genetic variants. Sixty-two full-genome sequences were determined, 52 of which were detectably recombinant. All but two recombinants contained predominantly MSV-A1-like sequences. Of the ten distinct recombination events observed, seven involved inter-MSV-A subtype recombination and three involved intra-MSV-A1 recombination. One of the intra-MSV-A1 recombinants, designated MSV-A1 UgIII, accounted for >60% of all MSV infections sampled throughout Uganda. Although recombination may be an important factor in the emergence of novel geminivirus variants, it is demonstrated that its characteristics in MSV are quite different from those observed in related African cassava-infecting geminivirus species. © 2007 SGM.

Minor head trauma – induced sporadic hemiplegic migraine coma

Familial hemiplegic migraine is a severe, rare subtype of migraine. Gene mutations on chromosome 19 have been identified in the calcium channel, voltage-dependent, P/Q type, alpha-1A subunit gene (chromosome 19p13) for familial hemiplegic migraine. Recently a gene mutation (Serine-218-Leucine) for a dramatic syndrome associated with familial hemiplegic migraine, commonly named “migraine coma”, has implicated exon 5 of this gene. The occurrence of trivial head trauma, in such familial hemiplegic migraine patients, may also be complicated by severe, sometimes even fatal, cerebral edema and coma occurring after a lucid interval. Sporadic hemiplegic migraine shares a similar spectrum of clinical presentation and genetic heterogeneity. The case report presented in this article implicates the involvement of the Serine-218-Leucine mutation in the extremely rare disorder of minor head trauma–induced migraine coma. We conclude that the Serine-218-Leucine mutation in the calcium channel, voltage-dependent, P/Q type, alpha-1A subunit gene is involved in sporadic hemiplegic migraine, delayed cerebral edema and coma after minor head trauma.

Phase III trial of gemcitabine and carboplatin versus mitomycin, ifosfamide, and cisplatin or mitomycin, vinblastine, and cisplatin in patients with advanced nonsmall cell lung carcinoma

BACKGROUND. The authors compared gemcitabine and carboplatin (GC) with mitomycin, ifosfamide, and cisplatin (MIC) or mitomycin, vinblastine, and cisplatin (MVP) in patients with advanced nonsmall cell lung carcinoma (NSCLC). The primary objective was survival. Secondary objectives were time to disease progression, response rates, evaluation of toxicity, disease-related symptoms, World Health Organization performance status (PS), and quality of life (QoL). METHODS. Three hundred seventy-two chemotherapy-naïve patients with International Staging System Stage III/IV NSCLC who were ineligible for curative radiotherapy or surgery were randomized to receive either 4 cycles of gemcitabine (1000 mg/m2 on Days 1, 8, and 15) plus carboplatin (area under the serum concentration-time curve, 5; given on Day 1) every 4 weeks (the GC arm) or MIC/MVP every 3 weeks (the MIC/MVP arm). RESULTS. There was no significant difference in median survival (248 days in the MIC/MVP arm vs. 236 days in the GC arm) or time to progression (225 days in the MIC/MVP arm vs. 218 days in the GC arm) between the 2 treatment arms. The 2-year survival rate was 11.8% in the MIC/MVP arm and 6.9% in the GC arm. The 1-year survival rate was 32.5% in the MIC/MVP arm and 33.2% in the GC arm. In the MIC/MVP arm, 33% of patients responded (4 complete responses [CRs] and 57 partial responses [PRs]) whereas in the GC arm, 30% of patients responded (3 CRs and 54 PRs). Nonhematologic toxicity was comparable for patients with Grade 3-4 symptoms, except there was more alopecia among patients in the MIC/MVP arm. GC appeared to produce more hematologic toxicity and necessitated more transfusions. There was no difference in performance status, disease-related symptoms, of QoL between patients in the two treatment arms. Fewer inpatient stays for complications were required with GC. CONCLUSIONS. The results of the current study failed to demonstrate any difference in efficacy between the newer regimen of GC and the older regimens of MIC and MVP. © 2003 American Cancer Society.

Randomized phase II trial of the efficacy and safety of trastuzumab combined with docetaxel in patients with human epidermal growth factor receptor 2-positive metastatic breast cancer administered as first-line treatment : the M77001 study group

Purpose: This randomized, multicenter trial compared first-line trastuzumab plus docetaxel versus docetaxel alone in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (MBC). Patients and Methods: Patients were randomly assigned to six cycles of docetaxel 100 mg/m 2 every 3 weeks, with or without trastuzumab 4 mg/kg loading dose followed by 2 mg/kg weekly until disease progression. Results: A total of 186 patients received at least one dose of the study drug. Trastuzumab plus docetaxel was significantly superior to docetaxel alone in terms of overall response rate (61% v 34%; P = .0002), overall survival (median, 31.2 v 22.7 months; P = .0325), time to disease progression (median, 11.7 v 6.1 months; P = .0001), time to treatment failure (median, 9.8 v 5.3 months; P = .0001), and duration of response (median, 11.7 v 5.7 months; P = .009). There was little difference in the number and severity of adverse events between the arms. Grade 3 to 4 neutropenia was seen more commonly with the combination (32%) than with docetaxel alone (22%), and there was a slightly higher incidence of febrile neutropenia in the combination arm (23% v 17%). One patient in the combination arm experienced symptomatic heart failure (1%). Another patient experienced symptomatic heart failure 5 months after discontinuation of trastuzumab because of disease progression, while being treated with an investigational anthracycline for 4 months. Conclusion: Trastuzumab combined with docetaxel is superior to docetaxel alone as first-line treatment of patients with HER2-positive MBC in terms of overall survival, response rate, response duration, time to progression, and time to treatment failure, with little additional toxicity. © 2005 by American Society of Clinical Oncology.

Crizotinib versus chemotherapy in advanced ALK-positive lung cancer

BACKGROUND: In single-group studies, chromosomal rearrangements of the anaplastic lymphoma kinase gene (ALK ) have been associated with marked clinical responses to crizotinib, an oral tyrosine kinase inhibitor targeting ALK. Whether crizotinib is superior to standard chemotherapy with respect to efficacy is unknown. METHODS: We conducted a phase 3, open-label trial comparing crizotinib with chemotherapy in 347 patients with locally advanced or metastatic ALK-positive lung cancer who had received one prior platinum-based regimen. Patients were randomly assigned to receive oral treatment with crizotinib (250 mg) twice daily or intravenous chemotherapy with either pemetrexed (500 mg per square meter of body-surface area) or docetaxel (75 mg per square meter) every 3 weeks. Patients in the chemotherapy group who had disease progression were permitted to cross over to crizotinib as part of a separate study. The primary end point was progression-free survival. RESULTS: The median progression-free survival was 7.7 months in the crizotinib group and 3.0 months in the chemotherapy group (hazard ratio for progression or death with crizotinib, 0.49; 95% confidence interval [CI], 0.37 to 0.64; P<0.001). The response rates were 65% (95% CI, 58 to 72) with crizotinib, as compared with 20% (95% CI, 14 to 26) with chemotherapy (P<0.001). An interim analysis of overall survival showed no significant improvement with crizotinib as compared with chemotherapy (hazard ratio for death in the crizotinib group, 1.02; 95% CI, 0.68 to 1.54; P=0.54). Common adverse events associated with crizotinib were visual disorder, gastrointestinal side effects, and elevated liver aminotransferase levels, whereas common adverse events with chemotherapy were fatigue, alopecia, and dyspnea. Patients reported greater reductions in symptoms of lung cancer and greater improvement in global quality of life with crizotinib than with chemotherapy. CONCLUSIONS: Crizotinib is superior to standard chemotherapy in patients with previously treated, advanced non-small-cell lung cancer with ALK rearrangement. (Funded by Pfizer; ClinicalTrials.gov number, NCT00932893.) Copyright © 2013 Massachusetts Medical Society.

Provisional matrix deposition in hemostasis and venous insufficiency: Tissue preconditioning for nonhealing venous ulcers

Significance: Chronic wounds represent a major burden on global healthcare systems and reduce the quality of life of those affected. Significant advances have been made in our understanding of the biochemistry of wound healing progression. However, knowledge regarding the specific molecular processes influencing chronic wound formation and persistence remains limited. Recent Advances: Generally, healing of acute wounds begins with hemostasis and the deposition of a plasma-derived provisional matrix into the wound. The deposition of plasma matrix proteins is known to occur around the microvasculature of the lower limb as a result of venous insufficiency. This appears to alter limb cutaneous tissue physiology and consequently drives the tissue into a ‘preconditioned’ state that negatively influences the response to wounding. Critical Issues: Processes, such as oxygen and nutrient suppression, edema, inflammatory cell trapping/extravasation, diffuse inflammation, and tissue necrosis are thought to contribute to the advent of a chronic wound. Healing of the wound then becomes difficult in the context of an internally injured limb. Thus, interventions and therapies for promoting healing of the limb is a growing area of interest. For venous ulcers, treatment using compression bandaging encourages venous return and improves healing processes within the limb, critically however, once treatment concludes ulcers often reoccur. Future Directions: Improved understanding of the composition and role of pericapillary matrix deposits in facilitating internal limb injury and subsequent development of chronic wounds will be critical for informing and enhancing current best practice therapies and preventative action in the wound care field.

Biocompatibility, SiH lenses and the impact of hydration on comfort

Silicone hydrogel (SiH) contact lenses have been available for over a decade. During that time, these highly innovative materials and designs have continually improved and now represent a major percentage of fits within the global contact lens market.1 Their high oxygen transmissibility has drastically reduced the incidence of hypoxia-related conditions such as corneal edema, limbal hyperaemia, and corneal vascularisation.2,3 However, there remain significant challenges in the quest for the ideal contact lens. The silicone material used in SiH contact lenses is inherently more hydrophobic than the non-silicone hydrogel materials. SiH lens manufacturers must find ways to overcome lens surface hydrophobicity since it can create issues in terms of lens wettability and surface deposition. Achieving ideal lens water content presents yet another challenge since increasing water content in a silicone hydrogel lens can reduce oxygen transmissibility. This is because increasing water content results in decreased silicone content in the lens and silicone is a better transmitter of oxygen than water.

Application of higher-order spectra for automated grading of diabetic maculopathy

Diabetic macular edema (DME) is one of the most common causes of visual loss among diabetes mellitus patients. Early detection and successive treatment may improve the visual acuity. DME is mainly graded into non-clinically significant macular edema (NCSME) and clinically significant macular edema according to the location of hard exudates in the macula region. DME can be identified by manual examination of fundus images. It is laborious and resource intensive. Hence, in this work, automated grading of DME is proposed using higher-order spectra (HOS) of Radon transform projections of the fundus images. We have used third-order cumulants and bispectrum magnitude, in this work, as features, and compared their performance. They can capture subtle changes in the fundus image. Spectral regression discriminant analysis (SRDA) reduces feature dimension, and minimum redundancy maximum relevance method is used to rank the significant SRDA components. Ranked features are fed to various supervised classifiers, viz. Naive Bayes, AdaBoost and support vector machine, to discriminate No DME, NCSME and clinically significant macular edema classes. The performance of our system is evaluated using the publicly available MESSIDOR dataset (300 images) and also verified with a local dataset (300 images). Our results show that HOS cumulants and bispectrum magnitude obtained an average accuracy of 95.56 and 94.39 % for MESSIDOR dataset and 95.93 and 93.33 % for local dataset, respectively.

Acute liver failure in children : a regional experience

Objective: To review the outcome of acute liver failure (ALF) and the effect of liver transplantation in children in Australia. Methodology: A retrospective review was conducted of all paediatric patients referred with acute liver failure between 1985 and 2000 to the Queensland Liver Transplant Service, a paediatric liver transplant centre based at the Royal Children's Hospital, Brisbane, that is one of three paediatric transplant centres in Australia. Results: Twenty-six patients were referred with ALF. Four patients did not require transplantation and recovered with medical therapy while two were excluded because of irreversible neurological changes and died. Of the 20 patients considered for transplant, three refused for social and/or religious reasons, with 17 patients listed for transplantation. One patient recovered spontaneously and one died before receiving a transplant. There were 15 transplants of which 40% (6/15) were < 2 years old. Sixty-seven per cent (10/15) survived > 1 month after transplantation. Forty per cent (6/15) survived more than 6 months after transplant. There were only four long term survivors after transplant for ALF (27%). Overall, 27% (6/22) of patients referred with ALF survived. Of the 16 patients that died, 44% (7/16) were from neurological causes. Most of these were from cerebral oedema but two patients transplanted for valproate hepatotoxicity died from neurological disease despite good graft function. Conclusions: Irreversible neurological disease remains a major cause of death in children with ALF. We recommend better patient selection and early referral and transfer to a transplant centre before onset of irreversible neurological disease to optimize outcome of children transplanted for ALF.

Hypoxic corneal changes following 8 hours of scleral contact lens wear

- Purpose To examine the change in corneal thickness and posterior curvature following 8 hours of miniscleral contact lens wear. - Methods Scheimpflug imaging (Pentacam HR, Oculus) was captured before, and immediately following, 8 hours of miniscleral contact lens wear for 15 young (mean age 22 ± 3 years), healthy participants with normal corneae. Natural diurnal variations were considered by measuring baseline corneal changes obtained on a separate control day without contact lens wear. - Results Over the central 6 mm of the cornea, a small, but highly statistically significant amount of edema was observed following 8 hours of miniscleral lens wear, after accounting for normal diurnal fluctuations (mean ± standard deviation percentage swelling 1.70 ± 0.98%, p < 0.0001). Posterior corneal topography remained stable following lens wear (-0.01 ± 0.07 mm steepening over the central 6 mm, p = 0.60). The magnitude of posterior corneal topographical changes following lens wear did not correlate with the extent of lens-related corneal edema (r = -0.16, p = 0.57). Similarly, the initial central corneal vault (maximum post-lens tear layer depth) was not associated with corneal swelling following lens removal (r = 0.27, p = 0.33). - Conclusions While a small amount of corneal swelling was induced following 8 hours of miniscleral lens wear (on average <2%), modern high Dk miniscleral contact lenses that vault the cornea do not induce clinically significant corneal edema or hypoxic related posterior corneal curvature changes during short-term wear. Longer-term studies of compromised eyes (e.g. corneal ectasia) are still required to inform the optimum lens and fitting characteristics for safe scleral lens wear to minimize corneal hypoxia.