Evaluation of a reduced dose protocol for respiratory gated lung computed tomography in an animal model

OBJECTIVE: We sought to evaluate and validate a low-dose protocol for respiratory-gated multislice computed tomography (CT) for volume calculations in small ventilated neonatal animals as a model for the ventilated human neonatal lung. MATERIALS AND METHODS: Five mechanically ventilated newborn piglets were imaged in a multislice CT scanner (0.5-mm slice thickness, 4:16 pitch, 0.5 seconds rotation time, 120 kV) using a normal (100 mAs) and a reduced (10 mAs) dose protocol. All animals were scanned twice (at 100 and 10 mAs) at each of 3 different ventilator settings. Complete volume datasets were reconstructed throughout the respiratory cycle in increments of 10% using retrospective half-scan reconstruction. End-inspiratory volumes and volumes during maximal expiration (functional residual capacity) were calculated by a customized software and values for normal and reduced dose protocols were compared using Kolmogorov-Smirnov test and Bland-Altman plots. RESULTS: Two volume datasets (one normal and one reduced dose protocol) showed artifacts on the axial images, which could not be analyzed by the software. Those values were determined after manual segmentation and excluded from final analysis. The mean (+/-SD) end-inspiratory volumes and functional residual capacity were 34.3 +/- 10.1 mL and 25.3 +/- 8.0 mL for the normal-dose protocol versus 33.1 +/- 10.0 mL and 24.7 +/- 8.1 mL for the reduced-dose protocol, respectively. There was no statistically significant difference between normal and reduced dose protocol (KS-Test: D = 0.14 < Dmax). CONCLUSION: Lung volume calculation in ventilated newborn piglets (end-inspiratory volumes and functional residual capacity) can be performed using respiratory-gated multislice CT even at a substantially reduced dose (eg, to 10 mAs). This makes the technique a candidate for future pediatric use.     

Bisphosphonate-related osteonecrosis of the jaw: clinical correlations with computerized tomography presentation

The aim of this study was to correlate clinical and computerized tomography (CT) features of bisphosphonate-related osteonecrosis of the jaws (BRONJ). All ONJ patients for whom there was complete CT scan imaging were eligible. Selected clinical parameters retrieved from their medical records were analyzed for correlation with CT parameters. The clinical presentation of BRONJ was supported by findings in CT imaging in 78.3%. The lesion’s size on CT correlated with the presence of purulent secretion (p?=?0.03). When sequestrum was present, the median lesion’s size on CT was relatively big (28 mm, range 21–43 mm). The mandibular canal cortex was never breached. CT has reasonable detection competence for diagnosing BRONJ. Purulent secretion indicates the likelihood that a more extensive involvement will be displayed on CT. A large lesion on CT should raise the index of suspicion for sequestrum. The CT appearance of a continuous cortex of the mandibular canal may serve as a differential parameter between BRONJ and metastasis to the jaw.     

Estimation of vaccine efficacy against acquisition of pneumococcal carriage

Evaluation of the effect of new conjugate vaccines on nasopharyngeal carriage of Streptococcus pneumoniae (pneumococcus) has been based on simple comparisons of the prevalence of carriage in vaccinees and controls. However, the definition and measurement of vaccine efficacy should be based on knowledge of the actual mechanism of the vaccine's effect. According to current knowledge, conjugate vaccines affect acquisition. We propose a simple-to-use method to measure vaccine efficacy against serotype-specific acquisition that needs only cross-sectional measurements of carriage. We demonstrate the use of the method by application to a data set where it is also possible to estimate efficacy against acquisition from longitudinal measurements.     

Sinus venosus atrial septal defect with partial anomalous pulmonary venous return: diagnosis with 64-slice spiral computed tomography at low radiation dose

The use of computed tomography is often debatable for pediatric patients because of the associated radiation exposure. Using a state-of-the-art 64-slice spiral computed tomography unit, we demonstrate the feasibility of lowering the radiation dose without losing essential diagnostic information in a case of a 2-year-old boy with a rare congenital heart defect.     

Impact of human immunodeficiency virus on survival after liver transplantation: analysis of United Network for Organ Sharing database

BACKGROUND: The outcome of liver transplantation (LT) in patients infected with human immunodeficiency virus (HIV) has been a matter of controversy. METHODS: A retrospective cohort study was performed to assess the impact of HIV on LT survival by using United Network for Organ Sharing registry Standard Transplant Analysis and Research files. RESULTS: A total of 138 HIV(+) and 30,520 HIV(-) patients who were > or =18 years old and underwent LT during the highly active antiretroviral therapy era (starting January 1, 1997) in the United States were included. Among all HIV(+) patients, the estimated 2-year survival probability was lower (70%) than among non-HIV patients (81%). This excess risk appeared entirely among those with coinfections, that is, HIV with hepatitis B virus or hepatitis C virus (HCV), as none of the 24 HIV-infected patients who did not have hepatitis B virus or HCV died during an average of 1.2 years of follow-up per person. Among HCV(+) patients, those with HIV coinfection had significantly lower survival rates than patients without HIV (P=0.006). Controlling for age, coinfection, Model for End-Stage Liver Disease scores, and other potential confounders in a proportional hazards regression analysis, HIV(+) patients had a hazard ratio of 1.41 (P=0.14, 95% confidence interval: 0.90-2.22) for mortality after LT. CONCLUSION: HIV(+) patients without HCV coinfection seemed to have good prognosis, whereas patients who had HIV/HCV coinfection had poor outcomes, which were significantly worse than that seen in those with HCV alone.     

Osteonecrosis of the jaw induced by orally administered bisphosphonates: incidence, clinical features, predisposing factors and treatment outcome

Summary Osteonecrosis of the jaw (ONJ) is a well-known devastating side effect of bisphosphonate therapy for cancer. Several ONJ cases of patients using oral bisphosphonates have been reported in the literature. The present study analyzed the clinical features, predisposing factors, and treatment outcome of 11 patients with oral bisphosphonates-related ONJ. Introduction and hypothesis Osteonecrosis of the jaw (ONJ) is a well-known side effect of parenteral bisphosphonates therapy. Although ONJ has been reported in patients using oral bisphosphonates, documentation of this entity is sparse. It was hypothesized that the clinical features, predisposing factors, and treatment outcome of this population are different from those of oncologic patients. Methods This retrospective bi-central study involved 98 ONJ patients, 13 of whom were treated with oral bisphosphonates. Two patients were excluded because of previous use of intravenous bisphosphonates. The profiles of 11 patients were analyzed. Results The mean duration of alendronate use before developing ONJ was 4.1 years. ONJ was triggered by dental surgery in 9 patients and by ill-fitted dentures in 2. Heavy smokers were the most recalcitrant subjects. Among the nine patients with at least 6 months of follow-up, ONJ healed completely in three, partially in four, and not at all in two. Conclusions ONJ is a rare devastating side effect of oral bisphosphonates associated with patient morbidity and high financial burden. Clinicians must be aware of this entity and inform patients of the risks of dental surgery. The synergistic effect of smoking in the pathogenesis of ONJ should be further investigated.     

Lack of evidence for contact sensitization by Pfiesteria extract

BACKGROUND: Members of the estuarine dinoflagellate genus Pfiesteria are reported to have been responsible for massive fish kills in the southeastern United States. Some reports suggest that exposure to waters having Pfiesteria blooms or occupation-related exposure might result in Pfiesteria-induced dermal irritation and inflammation. Although the toxin has not been isolated and purified, the original data suggested both hydrophilic and hydrophobic toxic components. Some investigators propose that dermonecrotic properties are associated with a hydrophobic fraction. OBJECTIVES: A bioactive C18-bound putative toxin (CPE) extracted from Pfiesteria-laden aquarium water during active fish-killing conditions was examined in the present study to evaluate its potential to produce inflammation and dermal sensitization and to determine whether the inflammation and dermatitis reported in early human exposure studies were allergic or irritant in nature. RESULTS: This fraction was cytotoxic to mouse Neuro-2A cells and primary human epidermal keratinocytes (NHEK) at a concentration of 1 mg/mL. Balb/C mice exposed to 50-200% CPE by skin painting exhibited a 6-10% increase in ear swelling relative to vehicle-treated mice in a primary irritancy assay. There was no increase in lymph node cell proliferation as measured using the local lymph node assay. Exposure to CPE in culture up-regulated interleukin-8 in NHEK, whereas granulocyte macrophage-colony-stimulating factor and tumor necrosis factor alpha were only minimally altered. CONCLUSIONS: This study suggests that CPE is cytotoxic to keratinocytes in culture at high concentrations and that it induces mild, localized irritation but not dermal sensitization.     

Upper airway imaging in sleep-disordered breathing: role of cone-beam computed tomography

Objective

To review recent use of three-dimensional (3D) imaging, specifically cone-beam computed tomography (CBCT), in the analysis of the upper airway for diagnosis or treatment outcomes in patients with sleep-disordered breathing (SDB).

Types of studies reviewed

Literature review of relevant medical and dental studies utilizing 3D imaging to assess the upper airway.

Results

Imaging of the upper airway provided insight into potential areas of obstruction. Accessibility of CBCT to dentists is reflected in several applications of upper airway diagnosis, treatment planning, and different treatment outcomes, as well as association with craniofacial development. However, multiple deficiencies in image acquisition, 3D reconstruction, and analysis are evident.

Practical implications

The role of CBCT in the analysis of the upper airway is growing; however, critical limitations remain. An understanding of these limitations, clarification of misconceptions, and improvements in analysis methods are required to ensure proper use and development of CBCT.