Reliability of Skeletal Muscle Area Measurement on CT with Different Parameters: A Phantom Study

ObjectiveTo evaluate the reliability of CT measurements of muscle quantity and quality using variable CT parameters.Materials and MethodsA phantom, simulating the L2–4 vertebral levels, was used for this study. CT images were repeatedly acquired with modulation of tube voltage, tube current, slice thickness, and the image reconstruction algorithm. Reference standard muscle compartments were obtained from the reference maps of the phantom. Cross-sectional area based on the Hounsfield unit (HU) thresholds of muscle and its components, and the mean density of the reference standard muscle compartment, were used to measure the muscle quantity and quality using different CT protocols. Signal-to-noise ratios (SNRs) were calculated in the images acquired with different settings.ResultsThe skeletal muscle area (threshold, −29 to 150 HU) was constant, regardless of the protocol, occupying at least 91.7% of the reference standard muscle compartment. Conversely, normal attenuation muscle area (30–150 HU) was not constant in the different protocols, varying between 59.7% and 81.7% of the reference standard muscle compartment. The mean density was lower than the target density stated by the manufacturer (45 HU) in all cases (range, 39.0–44.9 HU). The SNR decreased with low tube voltage, low tube current, and in sections with thin slices, whereas it increased when the iterative reconstruction algorithm was used.ConclusionMeasurement of muscle quantity using HU threshold was reliable, regardless of the CT protocol used. Conversely, the measurement of muscle quality using the mean density and narrow HU thresholds were inconsistent and inaccurate across different CT protocols. Therefore, further studies are warranted in future to determine the optimal CT protocols for reliable measurements of muscle quality.     

Impact of an Education Program for Caregivers of Patients with Alzheimer's Disease on Treatment Discontinuation and Compliance in Korea

Background and PurposeReportedly 30–50% of patients being treated for chronic illnesses do not adhere to their medication regimen. We assessed the impact of a nurse-led education program for caregivers of Korean de novo Alzheimer''s disease patients who had newly been prescribed donepezil.MethodsThis multicenter study analyzed 93 participants in a caregiver education group and 92 participants in a caregiver no-education group. At every visit up to the end of the study (1 year), caregivers in the education group were given educational brochures regarding Alzheimer''s disease and the efficacy and adverse events of donepezil treatment. The primary endpoint was the discontinuation rate of donepezil treatment during the 1-year observation period. The secondary endpoints included the effect of education on compliance with donepezil treatment assessed at each visit using a clinician rating scale (CRS) and visual analog scale (VAS), and changes from baseline in cognitive assessment tests.ResultsThe donepezil discontinuation rates at 1 year were 5.38% (5/93) and 6.52% (6/92) in the caregiver education and no-education groups, respectively (p=0.742). No significant between-group differences in donepezil compliance rates on the CRS and VAS were observed, but significant changes were observed in some cognitive tests from baseline to the end of the study.ConclusionsCaregiver education had no significant effect on treatment discontinuation, but this may have been due to the low severity of cognitive impairment among the included population at baseline. In addition, the low discontinuation rates meant that no significant difference in treatment compliance was observed.     

Long-term Outcomes of Endoscopic Variceal Ligation to Prevent Rebleeding in Children with Esophageal Varices

After an episode of acute bleeding from esophageal varices, patients are at a high risk for recurrent bleeding and death. However, there are few reports regarding the long-term results of secondary prophylaxis using endoscopic variceal ligation (EVL) against variceal rebleeding in pediatrics. Thirty-seven, who were followed for over 3 yr post-eradication, were included in the study. The mean duration of follow up after esophageal variceal eradication was 6.4±1.9 yr. The mean time required to achieve the eradication of varices was 3.25 months. The mean number of sessions and O-bands needed to eradicate varices was 1.9±1.2 and 3.8±1.5, respectively. During the period before the first EVL treatment, 145 episodes of bleedings developed in 37 children. Over the 3 yr of follow-up after variceal eradication, only 4 episodes of rebleeding developed in 4 of 37 patients. The four rebleeding episodes consisted of an esophageal variceal bleed, a gastric variceal bleed, a duodenal ulcer bleed, and a bleed caused by hemorrhagic gastritis. There was no mortality during long-term follow up after variceal eradication. During long-term follow up after esophageal variceal eradication using solely EVL in children with esophageal variceal bleeds, rebleeding episodes and recurrence of esophageal varices were rare. EVL is a safe and highly effective method for the long-term prophylaxis of variceal rebleeding in children with portal hypertension.     

New Metrics in High-Resolution and High-Definition Anorectal Manometry

Purpose of Review

To review recently published diagnostic methods that use high-resolution (HR-) or high-definition- (HD-) anorectal manometry (ARM) techniques.

Recent Findings

The integrated pressurized volume (IPV) is a new measure based on spatiotemporal plots obtained from HR-ARM. The IPV may be clinically useful for improving the prediction of abnormal balloon expulsion test in patients with constipation and for discriminating patients with anorectal disorders from asymptomatic controls. Combination of IPV parameters was superior to conventional manometric parameters in predicting the responsiveness to biofeedback therapy. Moreover, several novel parameters including the HR-ARM resting integral, HR-ARM squeeze profile, and anorectal asymmetry index may each be useful as predictive factors for identifying patients with fecal incontinence.

Summary

HR- and HD-ARM are increasingly performed worldwide for evaluation of anorectal function. Here, we describe new metrics whose clinical significance has not been fully established. Further standardization and validation of these metrics could provide clinically important new information and could help improve our understanding of the pathophysiology of anorectal disorders.

     

Phylogenetic Analyses of HBV Pre-S/S Genes in Mother-Child Pairs with Long-Term Infection by Presumed Vertical Transmission

Vertical transmission from mother to child, the main route of chronic hepatitis B virus (HBV) infection in the East Asia, is considered one of the most important predictors for the response to antiviral therapies as well as its complications such as cirrhosis and hepatocellular carcinoma. Therefore, it is critical in both etiologic and prognostic aspects to confirm whether or not chronic HBV infection is acquired vertically. This study investigated whether mother-to-child infection could be proved by the phylogenetic analyses of HBV pre-S/S genes ever since several decades have elapsed in mother-child pairs with presumed vertical transmission. The pre-S and S regions of HBVs were compared and analyzed phylogenetically in a total of 36 adults (18 mother-child pairs) with chronic HBV infection. All of the isolates of HBV were genotype C and serotype adr. The divergence between mothers and offsprings was 0 to 1.5%. Phylogenetic trees revealed that 17 of 18 pairs (94%) with presumed vertical transmission were grouped into the same cluster. Vertical transmission from mother to child could be strongly suggested even in adults with a history of several decades of HBV infection using the phylogenetic analyses of pre-S and S genes.

Graphical Abstract

相似文献