Evaluation of a Flexible 12-Channel Screen-printed Pediatric MRI Coil

Background Screen-printed MRI coil technology may reduce the need for bulky and heavy housing of coil electronics and may provide a better fit to patient anatomy to improve coil performance. Purpose To assess the performance and caregiver and clinician acceptance of a pediatric-sized screen-printed flexible MRI coil array as compared with conventional coil technology. Materials and Methods A pediatric-sized 12-channel coil array was designed by using a screen-printing process. Element coupling and phantom signal-to-noise ratio (SNR) were assessed. Subjects were scanned by using the pediatric printed array between September and November 2017; results were compared with three age- and sex-matched historical control subjects by using a commercial 32-channel cardiac array at 3 T. Caregiver acceptance was assessed by asking nurses, technologists, anesthesiologists, and subjects or parents to rate their coil preference. Diagnostic quality of the images was evaluated by using a Likert scale (5 = high image quality, 1 = nondiagnostic). Image SNR was evaluated and compared. Results Twenty study participants were evaluated with the screen-printed coil (age range, 2 days to 12 years; 11 male and nine female subjects). Loaded pediatric phantom testing yielded similar noise covariance matrices and only slightly degraded SNR for the printed coil as compared with the commercial coil. The caregiver acceptance survey yielded a mean score of 4.1 ± 0.6 (scale: 1, preferred the commercial coil; 5, preferred the printed coil). Diagnostic quality score was 4.5 ± 0.6. Mean image SNR was 54 ± 49 (paraspinal muscle), 78 ± 51 (abdominal wall muscle), and 59 ± 35 (psoas) for the printed coil, as compared with 64 ± 55, 65 ± 48, and 57 ± 43, respectively, for the commercial coil; these SNR differences were not statistically significant (P = .26). Conclusion A flexible screen-printed pediatric MRI receive coil yields adequate signal-to-noise ratio in phantoms and pediatric study participants, with similar image quality but higher preference by subjects and their caregivers when compared with a conventional MRI coil. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Lamb in this issue.

Printed Receive Coils with High Acoustic Transparency for Magnetic Resonance Guided Focused Ultrasound

In magnetic resonance guided focused ultrasound (MRgFUS) therapy sound waves are focused through the body to selectively ablate difficult to access lesions and tissues. A magnetic resonance imaging (MRI) scanner non-invasively tracks the temperature increase throughout the tissue to guide the therapy. In clinical MRI, tightly fitted hardware comprised of multichannel coil arrays are required to capture high quality images at high spatiotemporal resolution. Ablating tissue requires a clear path for acoustic energy to travel but current array materials scatter and attenuate acoustic energy. As a result coil arrays are placed outside of the transducer, clear of the beam path, compromising imaging speed, resolution, and temperature accuracy of the scan. Here we show that when coil arrays are fabricated by additive manufacturing (i.e., printing), they exhibit acoustic transparency as high as 89.5%. This allows the coils to be placed in the beam path increasing the image signal to noise ratio (SNR) five-fold in phantoms and volunteers. We also characterize printed coil materials properties over time when submerged in the water required for acoustic coupling. These arrays offer high SNR and acceleration capabilities, which can address current challenges in treating head and abdominal tumors allowing MRgFUS to give patients better outcomes.

A cost analysis of diabetic lower-extremity ulcers

OBJECTIVE

Our objectives were to 1) estimate the prevalence of diabetes and diabetic lower-extremity ulcers in the Medicare population, 2) characterize Medicare population-specific costs for lower-extremity ulcer episodes, and 3) evaluate potential cost savings associated with better healing of lower-extremity ulcers.

RESEARCH DESIGN AND METHODS

Prevalence and costs of diabetic lower-extremity ulcers were obtained by an analysis of Medicare claims data from 1995 and 1996 Standard Analytic Files (5% sample).

RESULTS

Medicare expenditures for lower-extremity ulcer patients were on average 3 times higher than those for Medicare patients in general ($15,309 vs. $5,226). Lower-extremity ulcer-related spending accounted for 24% of total spending for lower-extremity ulcer patients. Most of the ulcer-related costs accrued on the inpatient side (73.7%); proportionately smaller amounts went to physicians and nursing home facilities. To determine the potential effect of better diabetic ulcer management, a model was created that estimated the impact on costs with improved healing rates. Improving the 20-week healing rate from 31 to 40% would save Medicare $189 per episode.

CONCLUSIONS

Lower-extremity ulcers cost the Medicare system $1.5 billion in 1995. Any wound care intervention that could prevent even a small percentage of wounds from progressing to the stage at which inpatient care is required may have a favorable cost effect on the Medicare system.

Out-of-pocket health spending by poor and near-poor elderly Medicare beneficiaries

OBJECTIVE

To estimate out-of-pocket health care spending by lower-income Medicare beneficiaries, and to examine spending variations between those who receive Medicaid assistance and those who do not receive such aid. DATA SOURCES AND COLLECTION: 1993 Medicare Current Beneficiary Survey (MCBS) Cost and Use files, supplemented with data from the Bureau of the Census (Current Population Survey); the Congressional Budget Office; the Health Care Financing Administration, Office of the Actuary (National Health Accounts); and the Social Security Administration.

STUDY DESIGN

We analyzed out-of-pocket spending through a Medicare Benefits Simulation model, which projects out-of-pocket health care spending from the 1993 MCBS to 1997. Out-of-pocket health care spending is defined to include Medicare deductibles and coinsurance; premiums for private insurance, Medicare Part B, and Medicare HMOs; payments for non-covered goods and services; and balance billing by physicians. It excludes the costs of home care and nursing facility services, as well as indirect tax payments toward health care financing.

PRINCIPAL FINDINGS

Almost 60 percent of beneficiaries with incomes below the poverty level did not receive Medicaid assistance in 1997. We estimate that these beneficiaries spent, on average, about half their income out-of-pocket for health care, whether they were enrolled in a Medicare HMO or in the traditional fee-for-service program. The 75 percent of beneficiaries with incomes between 100 and 125 percent of the poverty level who were not enrolled in Medicaid spent an estimated 30 percent of their income out-of-pocket on health care if they were in the traditional program and about 23 percent of their income if they were enrolled in a Medicare HMO. Average out-of-pocket spending among fee-for-service beneficiaries varied depending on whether beneficiaries had Medigap policies, employer-provided supplemental insurance, or no supplemental coverage. Those without supplemental coverage spent more on health care goods and services, but spent less than the other groups on prescription drugs and dental care-services not covered by Medicare.

CONCLUSIONS

While Medicaid provides substantial protection for some lower-income Medicare beneficiaries, out-of-pocket health care spending continues to be a substantial burden for most of this population. Medicare reform discussions that focus on shifting more costs to beneficiaries should take into account the dramatic costs of health care already faced by this vulnerable population.