Diagnostic accuracy of ultrasonography and magnetic resonance imaging for the detection of fetal anomalies: a blinded case-control study

OBJECTIVES

To compare the accuracy of two-dimensional ultrasound (2D-US), three-dimensional ultrasound (3D-US) and magnetic resonance imaging (MRI) for the diagnosis of congenital anomalies without prior knowledge of indications and previous imaging findings.

METHODS

This was a prospective, blinded case-control study comprising women with a singleton pregnancy with fetal congenital abnormalities identified on clinical ultrasound and those with an uncomplicated pregnancy. All women volunteered to undergo 2D-US, 3D-US and MRI, which were performed at one institution. Different examiners at a collaborating institution performed image interpretation. Sensitivity and specificity of the three imaging methods were calculated for individual anomalies, based on postnatal imaging and/or autopsy as the definitive diagnosis. Diagnostic confidence was graded on a four-point Likert scale.

RESULTS

A total of 157 singleton pregnancies were enrolled, however nine cases were excluded owing to incomplete outcome, resulting in 148 fetuses (58 cases and 90 controls) included in the final analysis. Among cases, 13 (22.4%) had central nervous system (CNS) anomalies, 40 (69.0%) had non-CNS anomalies and five (8.6%) had both CNS and non-CNS anomalies. The main findings were: (1) MRI was more sensitive than 3D-US for diagnosing CNS anomalies (MRI, 88.9% (16/18) vs 3D-US, 66.7% (12/18) vs 2D-US, 72.2% (13/18); McNemar's test for MRI vs 3D-US: P = 0.046); (2) MRI provided additional information affecting prognosis and/or counseling in 22.2% (4/18) of fetuses with CNS anomalies; (3) 2D-US, 3D-US and MRI had similar sensitivity for diagnosing non-CNS anomalies; (4) specificity for all anomalies was highest for 3D-US (MRI, 85.6% (77/90) vs 3D-US, 94.4% (85/90) vs 2D-US, 92.2% (83/90); McNemar's test for MRI vs 3D-US: P = 0.03); and (5) the confidence of MRI for ruling out certain CNS abnormalities (usually questionable for cortical dysplasias or hemorrhage) that were not confirmed after delivery was lower than it was for 2D-US and 3D-US.

CONCLUSIONS

MRI was more sensitive than ultrasonography and provided additional information that changed prognosis, counseling or management in 22.2% of fetuses with CNS anomalies. False-positive diagnoses for subtle CNS findings were higher with MRI than with ultrasonography. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.

Cross-hemispheric functional connectivity in the human fetal brain

Compelling evidence indicates that psychiatric and developmental disorders are generally caused by disruptions in the functional connectivity (FC) of brain networks. Events occurring during development, and in particular during fetal life, have been implicated in the genesis of such disorders. However, the developmental timetable for the emergence of neural FC during human fetal life is unknown. We present the results of resting-state functional magnetic resonance imaging performed in 25 healthy human fetuses in the second and third trimesters of pregnancy (24 to 38 weeks of gestation). We report the presence of bilateral fetal brain FC and regional and age-related variation in FC. Significant bilateral connectivity was evident in half of the 42 areas tested, and the strength of FC between homologous cortical brain regions increased with advancing gestational age. We also observed medial to lateral gradients in fetal functional brain connectivity. These findings improve understanding of human fetal central nervous system development and provide a basis for examining the role of insults during fetal life in the subsequent development of disorders in neural FC.

Economic benefit of a 1-day reduction in hospital stay for community-acquired pneumonia (CAP)

OBJECTIVE

As a component of healthcare reform, payers, hospital administrators, and physicians are looking for ways to reduce hospital expenditures and improve efficiency. The economic benefit of a reduced hospital stay must be weighed against the cost of the treatment or process necessary to achieve the reduced length of stay (LOS). The objective of this paper was to estimate the potential economic benefit of a reduction in inpatient hospital LOS for a common type of admission, community acquired pneumonia (CAP).

RESEARCH DESIGN AND METHODS

Data for this study were from the CAP hospital admissions selected from the 2006 Healthcare Cost and Utilization Project (HCUP) National Inpatient Sample (NIS). Potential savings associated with a 1 day reduction in CAP LOS were estimated using three methods: (1) average cost, (2) weighted-average incremental cost of an additional day, and (3) weighted-average predicted mean costs from regression models which were used to estimate incremental cost adjusting for hospitalization characteristics.

MAIN OUTCOME MEASURES

Cost per day of CAP hospitalization.

RESULTS

A total of 1,471,295 CAP admissions qualified for the analysis. The cost for each day of reduction in LOS in 2009 US dollars was $2273, $2373, and $2319 for the three methods: simple average, incremental, and regression, respectively. Subgroup analysis and regression analysis indicated higher costs were identified: in patients who died in the hospital, had hospital stays in the Northeast or West, and in large hospitals. Longer CAP hospitalizations had a higher cost per additional day. Limitations include those typically associated with the use of administrative claims (e.g., lack of clinical detail, issues related to diagnosis coding).

CONCLUSIONS

Eliminating a day during the course of a CAP admission is potentially worth $2273-2373 in economic benefits (2009 dollars). As we strive for greater efficiency in healthcare delivery, changes in processes and/or improved diagnostics or treatments may potentially achieve a reduction in the length of stay. The cost of such changes or improvements must be weighed against the economic benefit of a shorter hospitalization.

Non-invasive fetal lung assessment using diffusion-weighted imaging

OBJECTIVES

The main goal was to develop a reproducible method for estimating the diffusion of water in human fetal lung tissue using diffusion-weighted imaging (DWI). A secondary objective was to determine the relationship of the apparent diffusion coefficients (ADCs) in the fetal lung to menstrual age and total lung volume.

METHODS

Normal pregnant volunteers were scanned on a 1.5-Tesla (T) magnetic resonance imaging (MRI) system. The MRI system was equipped with 40-mT/m gradients (slew rate 200 T/m/s, rise time 0.2 ms). A six-channel body array coil was used for signal reception. Single-shot DWI utilized TE/TR 125/3400 ms, slice thickness 4 mm, field of view 280 mm x 280 mm, interslice gap 0.8 mm and a matrix of 128 x 128. The voxel size was 2.5 mm x 2.5 mm x 4.0 mm. Two b-values (0 and 1000) were chosen along three orthogonal directions. ADC maps were created using assigned b-values. Simple linear regression was performed with Pearson correlation coefficient. Interexaminer and intraexaminer bias, and 95% limits of agreement (LOA) were determined using Bland-Altman plots.

RESULTS

Forty-seven scans were performed at a mean +/- SD of 29.2 +/- 4.5 weeks. The median coefficient of variation for ADC was 5.6% (interquartile range, 4.0-8.1%). No differences in ADC values were found between right and left lungs. Normally distributed ADC measurements were not significantly correlated with either total lung volume (r(2) = 0.0001, P = 0.94) or menstrual age (r(2) = 0.003, P = 0.70). The mean ADC value was 1.75 (95% CI, 1.63-1.86). Mean +/- SD intraexaminer bias was -0.15 +/- 2.3 (95% LOA, -4.7 to + 4.4) and interexaminer bias was 2.2 +/- 3.5 (95% LOA, -4.7 to + 9.1).

CONCLUSIONS

Our findings suggest that ADC measurements of the fetal lung are reproducible between blinded examiners and are independent of menstrual age, as well as lung volume.

Estimating the economic impact of a half-day reduction in length of hospital stay among patients with community-acquired pneumonia in the US

BACKGROUND

A recent study suggested that levofloxacin significantly reduces the hospital length of stay (LOS), by 0.5 days (p = 0.02), relative to moxifloxacin in patients with community-acquired pneumonia (CAP). The current analysis evaluated the potential economic impact of this half-day reduction in LOS.

METHODS

A cost model was developed to estimate the impact of a half-day reduction in LOS for CAP hospitalizations in the US. CAP incidence, hospitalization rate, and costs were obtained from published studies in PubMed and from publicly available government sources. The average daily cost of hospitalization was estimated for fixed costs, which comprise 59% of total inpatient costs. Costs from prior years were inflated to 2007 US dollars using the consumer price index. A range of cost savings, calculated using inpatient CAP costs from several studies, was extrapolated to the US CAP population.

RESULTS

Using the Centers for Disease Control National Hospital Discharge estimate of 5.3 days LOS for CAP, and an average cost (2007 $US) of $13,009 per CAP hospitalization, a daily fixed cost of $1448 was estimated. The resultant half-day reduction in costs associated with LOS was $724/hospitalization (range $457 to $846/hospitalization). When fixed and variable costs were considered, the estimated savings were $1227.27/episode. The incidence of CAP was estimated to be 1.9% (5.7 million cases/year based on current population census), and the estimated rate of CAP hospitalization was 19.6% (1.1 million annual hospitalizations). At $13,009/CAP-related hospitalization, total fixed inpatient costs of $8.6 billion annually were projected. The half-day reduction in LOS would therefore generate potential annual savings of approximately $813 million (range $513 million to $950 million). When total costs (fixed plus variable) were estimated, the mean savings for a half-day reduction would be approximately $1227/episode (range of $775 to $1434) or $1.37 billion annually in the US CAP population (range of $871 million to $1.6 billion). Limitations include the use of a single study for the estimation of fixed costs but a diversity of sources used for estimates of other variables, and lack of data with respect to the effects on costs of diagnostic-related groups, discounted contracts, and capitated payments.

CONCLUSIONS

A relatively small decrease in LOS in CAP can have a substantial cost impact, with estimated savings of $457 to $846 per episode or $500-$900 million annually. Additional evaluation is warranted for interpreting these cost-savings in the context of current antibiotic prescribing patterns.

Comparison of red blood cell transfusion rates of epoetin alfa and darbepoetin alfa in an inpatient oncology setting

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Background: Epoetin alfa (EPO) and darbepoetin alfa (DARB) are used to treat cancer-related anemia and to reduce the requirements for blood transfusions. To date, limited information on the relative effectiveness of these agents in the inpatient setting is available. This analysis evaluated red blood cell (RBC) transfusion rates in cancer patients receiving EPO or DARB during hospitalization. Methods: An analysis of electronic inpatient hospital records from the Premier Perspective Comparative Hospital Database was conducted to compare RBC transfusion rates in cancer patients receiving EPO or DARB therapy. Study subjects were identified through hospitalizations recorded between 07/2002 and 03/2005 from over 500 hospitals nationwide. Patients were required to be ≥18 years old, have a primary admitting diagnosis of cancer and be treated with EPO or DARB during hospitalization. Patients who had received renal dialysis were excluded. To minimize effects of outliers, 5% of patients with extreme doses in each group were excluded from the dosing analysis. In addition to descriptive statistics on transfusion requirements, a multivariate logistic model was employed to isolate the effect of an individual erythropoietic agent on the risk of RBC transfusion after controlling for patient demographics, comorbidities, admission characteristics, use of IV or oral iron and hospitalization severity markers. Results: Among the 24,814 EPO and 2,990 DARB study patients, mean age and gender distribution at admission were similar (age: EPO 65.3 years, DARB 64.5 years; %women: EPO 53%, DARB 55%). Mean cumulative dose per inpatient stay was EPO 61,656 ± 50,274 Units and DARB 259 ± 340 mcg. RBC transfusions occurred in 37.9% of EPO patients compared to 39.8% of DARB patients (p=0.0404). Transfused EPO patients received a mean of 2.24 units versus 2.20 units for DARB patients (p=0.2111). After adjusting for covariates, the multivariate model confirmed that DARB treatment was associated with a higher risk of transfusion compared to EPO (odds ratio: 1.2, 95% CI: 1.1–1.3, p=0.0007). Conclusions: This analysis of inpatients with cancer indicates DARB treatment is associated with a higher risk of receiving RBC transfusion compared to treatment with EPO.

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Stenting of proximal venous obstructions to maintain hemodialysis access

PURPOSE

The purpose of the study was to evaluate the efficacy of stenting central venous obstructions in patients dependent on hemodialysis to preserve or restore central venous patency and allow for continued hemodialysis from the affected side.

METHODS

Twenty-five self-expanding (17) and balloon-expandable (8) stainless steel stents were deployed in 19 patients with end-stage renal disease and central venous stenosis or occlusion. Nineteen lesions were treated: 11 subclavian and eight innominate. Twenty-two stents were initially implanted.

RESULTS

Stent deployment was successful in all cases and immediately remedied the underlying cause of venous hypertension. Follow-up at up to 17 months revealed three deaths from unrelated causes, one occlusion at 3.25 months, and three restenoses at 16 days, 2.5 and 5 months, respectively, with successful implantation of three additional stents for a primary central patency rate of 68% (+/- 14%) and secondary central patency rate of 93% (+/- 7%).

CONCLUSIONS

Stenting of subclavian and innominate venous stenoses and occlusions effectively corrected the underlying lesions responsible for disturbed hemodynamics and, in most cases, prolonged available hemodialysis access from the affected side. Stents seem to be valuable adjuncts in the management of failing hemodialysis access due to central venous stenosis or occlusion.