Left ventricle: automated segmentation by using myocardial effusion threshold reduction and intravoxel computation at MR imaging

This retrospective analysis of existing patient data had institutional review board approval and was performed in compliance with HIPAA. No informed consent was required. The purpose of the study was to develop and validate an algorithm for automated segmentation of the left ventricular (LV) cavity that accounts for papillary and/or trabecular muscles and partial voxels in cine magnetic resonance (MR) images, an algorithm called LV Myocardial Effusion Threshold Reduction with Intravoxel Computation (LV-METRIC). The algorithm was validated in biologic phantoms, and its results were compared with those of manual tracing, as well as those of a commercial automated segmentation software (MASS [MR Analytical Software System]), in 38 subjects. LV-METRIC accuracy in vitro was 98.7%. Among the 38 subjects studied, LV-METRIC and MASS ejection fraction estimations were highly correlated with manual tracing (R(2) = 0.97 and R(2) = 0.95, respectively). Ventricular volume estimations were smaller with LV-METRIC and larger with MASS than those calculated by using manual tracing, though all results were well correlated (R(2) = 0.99). LV-METRIC volume measurements without partial voxel interpolation were statistically equivalent to manual tracing results (P > .05). LV-METRIC had reduced intraobserver and interobserver variability compared with other methods. MASS required additional manual intervention in 58% of cases, whereas LV-METRIC required no additional corrections. LV-METRIC reliably and reproducibly measured LV volumes. Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/248/3/1004/DC1.     

HMG-CoA reductase inhibitors are associated with reduced mortality in ESRD patients.

BACKGROUND.: Patients with end-stage renal disease (ESRD) suffer from markedly higher rates of cardiovascular disease than the general population. Although therapy with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors ("statins") has been demonstrated to reduce the mortality from cardiovascular disease in patients without ESRD, only 10% of patients on dialysis are treated with these medications by day 60 of ESRD. We determined whether the use of statins is associated with a reduction in cardiovascular-specific death and total mortality in ESRD patients. METHODS: Data were analyzed from the U.S. Renal Data System Dialysis Morbidity and Mortality Wave-2 study, a cohort of randomly selected patients who were initiating dialysis in 1996. Information about the use of statins as well as other baseline characteristics was abstracted from the patients' dialysis records by dialysis personnel. Cox proportional hazards models were developed to determine the association between use of statins at baseline and subsequent risk of mortality, with adjustment for known mortality risk factors. RESULTS: Follow-up data were available for 3716 patients through July 1998. At baseline, 362 (9.7%) of patients were using statins. These patients had a mortality rate of 143/1000 person-years, compared with a rate of 202/1000 person-years for patients not using statins. Statin use was independently associated with a reduced risk of total mortality [relative risk (RR)=0.68, 95% confidence interval (CI)=0.54, 0.87] as well as cardiovascular-specific mortality (RR=0.64, 95% CI=0.45, 0.91). In contrast, the use of fibrates was not associated with reduced mortality (RR=1.29). CONCLUSIONS: Statin use was associated with a reduction in cardiovascular-specific death and total mortality in patients on dialysis.     

Long-term effects of cochlear implants in children.

OBJECTIVE: Since 1987, when the use of multichannel cochlear implants was initiated in children, candidacy has expanded; many thousands of children have received these devices, and results have revealed a wide range of performance. However, few long-term studies exist on a large population of these children. There have been concerns expressed that cochlear implant function might degrade over time, that devices and electrodes might migrate and extrude in the growing child, or that there might even be a deleterious effect of long-term stimulation of the cochlear nerve. The purpose of this study was to explore the long-term effects of implantation as a function of performance over time, reimplantation, and educational factors. STUDY DESIGN AND SETTING: We studied 81 children who received implants at a major academic medical center and were followed for 5 to 13 years. RESULTS: Results revealed significant gains in speech perception, use of oral language, and ability to function in a mainstream environment. There was no decrease in performance over time and no significant incidence of device or electrode migration or extrusion, and device failure did not cause a deterioration in long-term outcome. CONCLUSIONS: Multichannel cochlear implants in children provide perception, linguistic, and educational advantages, which are not adversely affected by long-term electrical stimulation.     

Angiotensin-converting enzyme genotype and outcome in pediatric IgA nephropathy

Angiotensin-converting enzyme (ACE) I/D polymorphism has been implicated as a genetic marker for progression of glomerular disease. Studies of ACE genotypes in adults with IgA nephropathy (IgAN) have yielded conflicting results. We performed ACE genotyping on 79 patients with IgAN diagnosed prior to age 18 years who had either progressed to end-stage renal disease (ESRD) or are now more than 5 years post biopsy. Mean follow-up was 14.8 years for those with normal renal function. Forty-three (54.4%) subjects had normal renal function and a normal urinalysis at last evaluation. Sixteen (20%) progressed to ESRD and 1 has chronic renal insufficiency. Kaplan-Meier survival curves for progression to ESRD did not differ significantly for the ACE DD, ID, and II genotype groups (P=0.095, log-rank test). By univariate analysis, presence of hypertension and degree of proteinuria at diagnosis, and unfavorable histology but not ACE genotype, was significantly associated with progression to ESRD. In the Cox proportional hazards model that included grade of proteinuria, the ACE D allele was a significant independent predictor of outcome with a hazard ratio of 2.37 (P=0.031). Our data, while inconclusive, suggest that the ACE D allele may associate with poor outcome in pediatric IgAN.     

Rectovaginal fistula model in the New Zealand white rabbit

Introduction and hypothesis  

The purpose of this study was to create an animal model to study rectovaginal fistula repair.     

Differential Complication Rates Following Radical Cystectomy in the Irradiated and Nonirradiated Pelvis

Background

Reports suggest that cystectomy following pelvic irradiation is associated with a higher morbidity and mortality than in primary cases. However, such reports are from an era when postcystectomy complication rates were higher than are currently reported.

Objective

This study evaluates perioperative complications and mortality in primary radical and postradiation salvage cystectomy.

Design, setting, and participants

Patients treated with cystectomy for bladder cancer or advanced pelvic malignancies involving the bladder were studied.

Measurements

Perioperative complications and mortality were analysed for 426 primary and 420 salvage cystectomies performed at a single institution between 1970 and 2005.

Results and limitations

The 30- and 60-d mortality in the 2000–2005 cohort were 0% and 1.2%, respectively, in the primary group and 1.4% and 4.3%, respectively, in the salvage cystectomy group. Thirty-day mortality between 1970 and 2005 was not statistically significant in the primary and salvage groups (4.2% and 7.1%, respectively).

Conclusions

This large series from a high-volume centre demonstrates no difference in perioperative mortality in primary or postradiation salvage radical cystectomy. Similarly, there was no significant difference in the incidence of most of the surgical or medical complications in either group, although the stomal stenosis rate was higher postradiation.     

Chitosan Sponges to Locally Deliver Amikacin and Vancomycin: A Pilot In Vitro Evaluation

Background

Open orthopaedic wounds are ideal sites for infection. Preventing infection in these wounds is critical for reducing patient morbidity and mortality, controlling antimicrobial resistance and lowering the cost of treatment. Localized drug delivery has the potential to overcome the challenges associated with traditional systemic dosing. A degradable, biocompatible polymer sponge (chitosan) that can be loaded with clinician-selected antibiotics at the point of care would provide the patient and clinician with a desirable, adjunctive preventive modality.

Questions/purposes

We asked (1) if an adaptable, porous chitosan matrix could absorb and elute antibiotics for 72 hours for potential use as an adjunctive therapy to débridement and lavage; and (2) if the sponges could elute levels of antibiotic that would inhibit growth of Staphylococcus aureus and Pseudomonas aeruginosa?

Methods

We fabricated a degradable chitosan sponge that can be loaded with antibiotics during a 60-second hydration in drug-containing solution. In vitro evaluation determined amikacin and vancomycin release from chitosan sponges at six time points. Activity tests were used to assess the release of inhibitory levels of amikacin and vancomycin.

Results

Amikacin concentration was 881.5 μg/mL after 1 hour with a gradual decline to 13.9 μg/mL after 72 hours. Vancomycin concentration was 1007.4 μg/mL after 1 hour with a decrease to 48.1 μg/mL after 72 hours. Zone of inhibition tests were used to verify inhibitory levels of drug release from chitosan sponges. A turbidity assay testing activity of released amikacin and vancomycin indicated inhibitory levels of elution from the chitosan sponge.

Clinical Relevance

Chitosan sponges may provide a potential local drug delivery device for preventing musculoskeletal infections.     

Review article: Renal support in critical illness

Purpose

This review provides a focused and comprehensive update on established and emerging evidence in acute renal replacement therapy (RRT) for critically ill patients with acute kidney injury (AKI).

Principal findings

There have been considerable technological innovations in the methods and techniques for provision of extracorporeal RRT in critical illness. These have greatly expanded our capability to provide both renal and non-renal life-sustaining organ support for critically ill patients. Recent data suggest earlier initiation of RRT in AKI may confer an advantage for survival and renal recovery. Two large trials have recently shown no added benefit to augmented RRT dose delivery in AKI. Observational data have also suggested that fluid accumulation in critically ill patients with AKI is associated with worse clinical outcome. However, several fundamental clinical questions remain to be answered, including issues regarding the time to ideally initiate/discontinue RRT, the role of high-volume hemofiltration or other blood purification techniques in sepsis, and extracorporeal support for combined liver-kidney failure. Extracorporeal support with RRT in sepsis, rhabdomyolysis, and liver failure are discussed, along with strategies for drug dosing and management of RRT in sodium disorders.

Conclusions

We anticipate that this field will continue to expand to promote research and innovation, hopefully for the benefit of sick critically ill patients.     

The Impact of Bariatric Surgery on Menstrual Patterns

Background: Obesity and anovulation are common medical problems in the United States. Anovulation in obese patients primarily manifests with irregular, sporadic or absent menstrual bleeding. Weight loss of at least 5% has been shown to reverse obesity-related anovulation. The aim of this study was to assess the impact of bariatric surgery on infertility in morbidly obese women and to identify factors associated with return of normal menses following bariatric surgery. Methods: A survey of patients was collected from the bariatric surgery data-base at the Hospital of the University of Pennsylvania. 410 women under the age of 40 were sent questionnaires. 195 patients completed the questionnaire, and 29 patients had incorrect addresses without a forwarding address, resulting in a 51.2% response rate. Patients who reported menstrual cycle lengths >35 days were considered abnormal. 92 of the 195 responders were considered anovulatory preoperatively, based on menstrual history. Results: There was no significant difference in postoperative BMI, BMI decrease or age at surgery between the survey responders and non-responders. There was a significant difference between these 2 groups in time since surgery (P=.01). Both groups had a decrease in BMI of >18 kg/m². The mean menstrual cycle length preoperatively among those categorized as ovulatory and anovulatory was 27.3 and 127.5 days, respectively. Of the 98 patients who were anovulatory preoperatively, 70 patients (71.4%) regained normal menstrual cycles after surgery. Those patients who regained ovulation had greater weight loss than those who remained anovulatory (61.4 kg vs 49.9 kg, P=0.02). Conclusions: Anovulation resulting in abnormal menses is a common problem in morbidly obese premenopausal women. The menstrual cycle disorders may completely resolve after bariatric surgery. Thus, infertility due to anovulation among morbidly obese women could potentially be viewed as an additional indication for bariatric surgery.