Open-floored concave compensating filter for angiography

An open-floored concave compensating filter was designed that produced a radiograph of uniform density, caused no artifacts due to its shape or position, and required little or no increase in exposure in most applications. Selective celiac, hepatic, shoulder, and pelvic angiography was performed with use of the filter; image quality was noticeably improved.     

Reducing a peritoneal dialysis program's cost by changing from a vendor-provided to a program-provided system for general medical supplies: significant savings in CCPD

An examination of the costs associated with outpatient chronic peritoneal dialysis prompted us to investigate the charges for general medical supplies used by patients on continuous ambulatory peritoneal dialysis (CAPD) and continuous cycling peritoneal dialysis (CCPD) in our hospital-owned, not-for-profit peritoneal dialysis program. The items used by patients to perform their dialysis exchanges and daily exit site care included 4 x 3 and 2 x 2 sterile gauze pads, antibacterial soap, masks, tape, and betadine swabsticks. The charges for these supplies when purchased from the dialysis vendor were compared with charges for the same items if purchased directly from hospital stores by the peritoneal dialysis program and then distributed to the patients. This initial analysis suggested a considerable savings if the peritoneal dialysis program provided the supplies. Based on this estimated savings, in July 1995, the peritoneal dialysis program changed from a vendor-provided to a program-provided system for general supplies used by CAPD and CCPD patients. This study examined the differences in charges expressed as $/patient-month for two periods: July 1994 to June 1995 (when all general medical supplies were provided by dialysis vendors directly to the CAPD and CCPD patients) and July 1995 to May 1996 (when the peritoneal dialysis program purchased general medical supplies from hospital stores and distributed these supplies directly to the patients). The median vendor charges for CAPD patients (n = 21 during 1994 to 1995 and n = 18 during 1995 to 1996) were not significantly different between the two periods. In fact, the charges were slightly higher during the 1995 to 1996 period ($1,264/patient-month v $1,193/patient-month during the vendor-provided period of July 1994 to June 1995, P = 0.67). The median vendor charges for patients on CCPD were significantly lower during the 1995 to 1996 period when the peritoneal dialysis program provided the general medical supplies used for CCPD ($1,110/patient-month v $1,389/patient-month during 1994 to 1995, P = 0.003). There were 30 CCPD patients during the 1994 to 1995 period and 27 patients on CCPD during 1995 to 1996. The total charges for CAPD and CCPD patients combined included dialysis vendor charges (dialysis solution, tubing, cycler rental) and charges from hospital stores. These total charges were lower in the July 1995 to May 1996 period when general medical supplies were purchased directly from hospital stores rather than from the dialysis vendors: $1,201/patient-month versus $1,360/patient-month (P = 0.03). The median hospital store charges rose slightly during the July 1995 to May 1996 period when supplies were purchased by the peritoneal dialysis program from hospital stores ($31/patient-month v $21/patient-month, P = 0.37, during the July 1994 to June 1995 period when general medical supplies were purchased directly from dialysis vendors). However, despite the rise in charges from hospital stores, an overall savings of $149/patient-month was achieved when the peritoneal dialysis program purchased and provided general medical supplies used by the peritoneal dialysis patients. This $149/patient-month equals $1,788 savings per dialysis year for each patient on peritoneal dialysis for that year. Significant savings in the cost of a chronic peritoneal dialysis program may therefore occur if less expensive sources for the general medical supplies used by CAPD and, especially, CCPD patients are found.     

An examination of the renal transplant evaluation process focusing on cost and the reasons for patient exclusion

A medical evaluation of prospective renal transplant recipients is performed to identify conditions that may exclude patients from transplantation because of unacceptable risks. Protocols for evaluating potential transplant candidates are available, but there is little information about reasons for excluding patients from transplantation. To assess the effectiveness and cost of our renal transplant-recipient evaluation process, we retrospectively reviewed patients excluded from renal transplantation between January 1993 and December 1995 to categorize the reasons for exclusion. We also examined the costs of the evaluation. The study group included all adults referred for kidney-only transplantation during the study period who were excluded from transplantation (n=125). Demographics of the 160 patients with end-stage renal disease (ESRD) who underwent renal transplantation during the study period were also examined. Compared with the patients who underwent transplantation, the excluded patients were older (48+/-14 v 43+/-12 years; P=0.006) and more likely to be women (66 of 125 patients; 53% v 57 of 160 patients; 36%; P=0.005) and diabetic (59 of 125 patients; 47% v 30 of 160 patients; 19%; P=0.005). The most common reason for excluding patients was medical contraindication (46%), followed by patient declined (25%), obesity (10%, defined as a body mass index [BMI] > or = 35), patient death (6%), and insurance/financial (5%). The medical reasons for exclusion were heart disease (38%), noncompliance (28%), miscellaneous (22%), and cancer (12%). Tests performed after the initial evaluation included cardiac testing (stress thallium or echocardiography and coronary angiography) in 50 patients, Doppler studies of the lower extremities in 28 patients, and hepatitis C polymerase chain reaction (PCR) or recombinant immunoblot assay (RIBA) assays in 8 patients. The cost of standard pretransplantation blood work for selected tests (ABO blood group typing, HLA, hepatitis B and C, and cytomegalovirus) was $709. Deferring such routine pretransplantation blood work until after the patient education session and history and physical examinations by nephrology and surgery in the 31 patients (25%) who declined transplantation at the initial visit would have resulted in considerable savings. Our evaluation process now includes prereferral information on a prospective recipient's medical problems, height and weight, and basic screening laboratory tests. This protocol has resulted in a more efficient and cost-effective evaluation process. Further examination of the cost-effectiveness of the transplant evaluation process is warranted.     

Cortical variability and asymmetry in normal aging and Alzheimer's disease

The onset of Alzheimer's disease (AD) is accompanied by a complex and distributed pattern of neuroanatomic change, difficult to distinguish clinically from dynamic alterations in normal aging. Extreme variations in the sulcal patterns of the human cortex have made it difficult to identify diffuse and focal variations in cortical structure in neurodegenerative disease. We report the first comprehensive 3D statistical analysis of deep sulcal structure in vivo, in both normal aging and dementia. High-resolution 3D T1-weighted fast SPGR (spoiled GRASS) MRI volumes were acquired from 10 patients diagnosed with AD (NINCDS-ARDRA criteria; age: 71.9 +/- 10.7 years) and 10 normal subjects matched for age (72.9 +/- 5.6 years), gender, educational level and handedness. Scans were digitally transformed into Talairach stereotaxic space. To determine specific patterns of cortical variation in dementia patients, 3D average and probabilistic maps of primary deep sulci were developed for both normal and AD groups. Major sulci (including supracallosal, cingulate, marginal, parieto-occipital, anterior and posterior calcarine sulci, and Sylvian fissures) were modeled as complex systems of 3D surfaces using a multi-resolution parametric mesh approach. Variations and asymmetries in their extents, curvature, area and surface complexity were evaluated. Three- dimensional maps of anatomic variability, structural asymmetry and local atrophy indicated severe regionally selective fiber loss in AD. A midsagittal area loss of 24.5% at the corpus callosum's posterior midbody (P < 0.025) matched increases in structural variability in corresponding temporo-parietal projection areas. Confidence limits on 3D cortical variation, visualized in 3D, exhibited severe increases in AD from 2 to 4 mm at the callosum to a peak SD of 19.6 mm at the posterior left Sylvian fissure. Normal Sylvian fissure asymmetries (right higher than left; P < 0.0005), mapped for the first time in three dimensions, were accentuated in AD (P < 0.0002), and were greater in AD than in controls (P < 0.05). Severe AD-related increases in 3D variability and asymmetry may reflect disease-related disruption of the commissural system connecting bilateral temporal and parietal cortical zones, regions known to be at risk of early metabolic dysfunction, perfusion deficits and selective neuronal loss in AD.