Parathyroid imaging: comparison of double-tracer (T1-201, Tc-99m) scintigraphy and high-resolution US

Parathyroid scintigraphy using a double-tracer (T1-201, Tc-99m) subtraction technique depicted 17 of 23 (74%) parathyroid adenomas in patients with and without previous neck operations. High-resolution (10-MHz) ultrasound (US) depicted 18 (78%) of these adenomas. Average tumor size depicted by US was 17 X 10 X 8 mm (excluding a giant adenoma) and 19 X 10 X 9 mm by scintigraphy. Alone, neither modality was particularly sensitive in the depiction of primary hyperplasia of the parathyroid glands, but combined techniques were more effective than the use of a single modality. With both US and T1-201 scintigraphy, only two of 23 cases of parathyroid adenoma in the neck were missed, and none of the eight cases of secondary hyperplasia were missed. In 11 patients who had previously undergone neck surgery, parathyroid tumors were identified in eight by either US or double-tracer scintigraphy. Preoperative parathyroid imaging with double-tracer scintigraphy and high-resolution US is suggested for patients with hyperparathyroidism, particularly in those patients who have had previous parathyroid surgery.     

Intrathecal synthesis of IgG in HIV infections

CSF and serum of 80 HIV-seropositive patients in various stages of the disease were examined. Total as well as intrathecal IgG synthesis appeared to be frequently elevated in each diagnostic group. Abnormal CSF oligoclonal IgG fractions were significantly more frequent in asymptomatic patients. CSF pleocytosis was found with a lower percentage in neurological AIDS patients. In patients subdivided according to blood T helper cell count, the distribution of the abnormal CSF parameters confirms that the immunological response in the CNS is mediated by interaction with systemic immunity.     

Superparamagnetic iron oxide-enhanced MR imaging: pulse sequence optimization for detection of liver cancer

The effects of magnetic resonance (MR) pulse sequences and timing parameters on tumor-liver contrast were studied in an animal model of metastatic liver cancer. Six spin-echo (SE), three inversion-recovery (IR), and four gradient-echo (GRE) sequences were evaluated at 0.6 T before and after injection of super-paramagnetic iron oxide. GRE techniques, irrespective of echo time and flip angle, showed the greatest change in signal intensity (enhancement) of the liver after administration of iron oxide. Single-acquisition GRE sequences (16 seconds) matched the contrast-to-noise ratio (C/N) performance of the most effective 6.4-minute SE sequences. Multiexcitation GRE sequences showed tumor-liver C/Ns per unit time that were significantly (P less than .05) higher than those achieved with SE and IR sequences. GRE sequences, which recruit intravoxel dephasing as an additional source of transverse relaxation enhancement (T2*), show a higher C/N per unit time and in this respect seem superior to SE and IR sequences for MR imaging with superparamagnetic iron oxide.     

A study of confidential unit exclusion

The effectiveness of the confidential unit exclusion (CUE) procedure recommended by the Food and Drug Administration has been questioned by the blood banking community. The purpose of this study was to determine whether donors were informing the blood center correctly regarding the disposition (transfuse or do not transfuse) of their donated blood. A letter explaining the confidential study and requesting permission to send the participant a questionnaire noting his or her self-exclusion choice was mailed to 230 donors who had chosen transfuse and 276 donors who had chosen do not transfuse. After consent was obtained, participants were sent a second packet and asked to indicate whether they had chosen correctly and, if not, to identify reasons for that incorrect choice. A seven-word terminology quiz made up of words from the CUE form was also enclosed. All participants who had chosen transfuse indicated that this was the correct choice. Approximately 50 percent of those who had chosen do not transfuse indicated that this was an incorrect choice; the most common reason was that "I was not paying attention." The most frequently misunderstood term was "confidential." Donors who chose do not transfuse had a significantly higher rate of error on the terminology quiz (p less than 0.01) than did those who chose transfuse.     

Hospitals' Negotiating Leverage with Health Plans: How and Why Has It Changed?

Objective.  To describe how hospitals' negotiating leverage with managed care plans changed from 1996 to 2001 and to identify factors that explain any changes.
Data Sources.  Primary semistructured interviews, and secondary qualitative (e.g., newspaper articles) and quantitative (i.e., InterStudy, American Hospital Association) data.
Study Design.  The Community Tracking Study site visits to a nationally representative sample of 12 communities with more than 200,000 people. These 12 markets have been studied since 1996 using a variety of primary and secondary data sources.
Data Collection Methods.  Semistructured interviews were conducted with a purposive sample of individuals from hospitals, health plans, and knowledgeable market observers. Secondary quantitative data on the 12 markets was also obtained.
Principal Findings.  Our findings suggest that many hospitals' negotiating leverage significantly increased after years of decline. Today, many hospitals are viewed as having the greatest leverage in local markets. Changes in three areas—the policy and purchasing context, managed care plan market, and hospital market—appear to explain why hospitals' leverage increased, particularly over the last two years (2000–2001).
Conclusions.  Hospitals' increased negotiating leverage contributed to higher payment rates, which in turn are likely to increase managed care plan premiums. This trend raises challenging issues for policymakers, purchasers, plans, and consumers.