Comparison of spin-echo and gradient-echo T1-weighted and spin-echo T2-weighted images at 3T in evaluating term-neonatal myelination.

SUMMARY: A prior clinical report of 3T MR imaging in subsequently healthy very premature neonates imaged at term-equivalent age found that both gradient recalled-echo-T1WI and spin-echo-T2WI showed higher rates of myelinated structures, compared with spin-echo-T1WI. The current study set out to assess those rates on the same sequences at 3T in term neonates and thus consisted of 16 term neonates with normal-appearing MR imaging findings who subsequently had normal findings at clinical follow-up. Two neuroradiologists independently assessed 19 structures in those infants on all 3 sequences. Gradient recalled-echo-T1WI showed a slightly higher rate of myelination (57.2%-72.4% of all structures) and interobserver agreement (κ = 0.546, P < .0001) than spin-echo-T2WI (58.2%-64.8%; κ = 0.468, P < .0001), while spin-echo-T1WI had the lowest myelination rate and agreement (25.0%-48.4%; κ = 0.384, P < .0001). Both observers noted that the following structures were myelinated in 88%-100% of patients on gradient recalled-echo-T1WI: the brachium of the inferior colliculus, decussation of the superior cerebellar peduncle, habenular commissure, medial lemniscus, pyramidal decussation, posterior limb of the internal capsule, and superior cerebellar peduncle; on spin-echo-T2WI, there was myelination in 88%-100% of the following structures: the brachium of the inferior colliculus, decussation of the superior cerebellar peduncle, inferior cerebellar peduncle, medial lemniscus, and posterior limb of the internal capsule. In conclusion, this study confirmed that similar to the findings in term-equivalent-age premature infants, myelination changes in term neonates may be best assessed on both gradient recalled-echo-T1WI and spin-echo-T2WI at 3T, and not on spin-echo-T1WI.

Economic outcome under Medicare prospective payment at a tertiary-care institution: the effects of demographic, clinical, and logistic factors on duration of hospital stay and part A charges for medical back problems (DRG 243).

We investigated the effects of prospectively identified factors on the duration of hospital stay and part A charges in 240 hospitalizations (of 230 patients) for the diagnosis-related group "medical back problems" (DRG 243) at a tertiary-care institution in 1985 to determine whether heterogeneity existed within this reimbursement category. We confirmed our initial postulates that nonosteoporotic fractures and neck problems, as well as hospitalizations primarily for myelography after outpatient neurologic evaluation, had considerably different economic outcomes and thus excluded these categories from further analysis. Statistical analysis (forward stepwise regression) of the remaining 132 patients who had "general medical back problems" showed that increasing age, associated osteoporosis, and therapeutic injections best explained variation in the natural logarithm of duration of stay (R2 = 0.16). Total number of diagnoses, spondylosis, associated osteoporosis, age, therapeutic injections, and performance of special procedures best explained the variation in the logarithm of part A charges (R2 = 0.29). The ability to identify factors within a specified category that affect the duration of hospitalization and part A charges jeopardizes the fairness of prospective payment, and we believe that DRG 243 should be adjusted for age, comorbidity, and readily identifiable clinical syndromes that have disparate economic consequences. Because of poorly substantiated efficacy and a significant association with longer hospital stays and higher part A charges, clinicians should review the use of therapeutic injections for medical back problems. Analysis of case-mix such as ours should be helpful in promoting efficient practice and ensuring the fairness of any reimbursement system.

Reduction mammaplasty: an outcome study.

Outcome studies of the value of reduction mammaplasties have only recently appeared in the literature. Medical directors of insurance companies and managed care plans have been reluctant to pay for reduction mammaplasties, citing the uncertainty of the medical necessity of the procedure. They have defended their position by stating that the medical literature is devoid of studies documenting that reduction mammaplasty is medically beneficial to the patient. For this reason, reduction mammaplasty is often excluded from health care benefit plans. Because of the need for outcome studies for this procedure, the charts of 363 consecutive patients who had reduction mammaplasty at the Mayo Clinic from January of 1986 to December of 1993 were reviewed. Questionnaires were sent to all these patients asking them to evaluate their outcome, and 328 responded (90.4 percent response rate). Of the respondents, 94.2 percent believed that the procedure was completely or very successful, and only 1.5 percent believed that it was not very successful or completely unsuccessful. The symptoms most frequently reported by patients preoperatively were as follows: uncomfortable feeling about their body, 97.0 percent: inability to find clothes that fit, 95.7 percent; pain in bra-strap groove, 92.4 percent; shoulder pain, 86.0 percent; inability to run, 79.3 percent; upper back pain, 79.0 percent; inability to participate in sports, 77.4 percent; neck pain, 70.7 percent; lower back pain, 64.0 percent; and intertrigo, 61.0 percent. The symptoms least frequently reported by patients preoperatively were as follows: pain or numbness in the hands, 22.6 percent; headaches, 30.2 percent; arm pain, 35.4 percent; and breast pain, 58.2 percent. These symptoms were either relieved or partially relieved in 88 percent or more of the patients. Of the 328 patients, 97.3 percent responded that they definitely or probably would have the procedure again, and only 1.2 percent definitely or probably would not have the operation again. Evaluation of medical treatment used to relieve symptoms showed a marked decrease in the need for such measures after reduction mammaplasty. Study of the charges for the procedure revealed that the setting of practice parameters for the procedure and the use of an ambulatory surgery center significantly decreased the charges for the procedure. This outcome study supports the hypothesis that reduction mammaplasty is an effective procedure and the treatment of choice for symptomatic mammary hyperplasia.

Hypothalamic sarcoidosis and hypopituitarism.

4 patients with presumed pituitary hypothalamic sarcoidosis are described. 3 had histological diagnoses compatible with sarcoidosis and in the other this diagnosis was strongly suspected from chest X-rays. 2 patients presented with diabetes insipidus. ACTH reserve was diminished in 3 out of 4 and growth hormone reserve was diminished in the 3 who were tested. All 4 patients developed secondary amenorrhea. 3 patients had hypothalamic hypothyroidism. Prolactin dynamics were intact. Tomograms of the sella turcica in all 4 and computerized tomography of the hypothalamic area in 2 patients failed to reveal any abnormality.

Furosemide-induced reduction in ionized calcium in hypoparathyroid patients.

Six hypoparathyroid patients were treated with oral furosemide for 4 days. All six had a significant decrease in serum ionized calcium level from the control period (4.05 +/- 0.31 mg/dl) to the furosemide period (3.46 +/- 0.26 mg/dl, P less than 0.005). In five patients, the decrease in serum ionized calcium concentration occurred in association with an increase in urinary calcium excretion. Although serum immunoreactive parathyroid hormone level increased in five patients, it was insufficient to return serum ionized calcium to control levels. Changes in serum phosphorus, magnesium, or pH could not account for the observed decrease in serum ionized calcium concentration. It is necessary to monitor serum ionized calcium level in hypoparathyroid patients during furosemide therapy.

rab3 is a small GTP-binding protein exclusively localized to synaptic vesicles.

rab3, a low molecular weight GTP-binding protein, is primarily expressed in brain, where it is present in soluble and membrane-bound forms. Membrane-bound rab3 in brain is exclusively localized on synaptic vesicles, the secretory organelles of the synapse that store and release neurotransmitters. rab3 is also expressed in endocrine tissues such as the adrenal medulla, where it is found together with other synaptic vesicle proteins on microvesicles distinct from chromaffin granules. The tight binding of rab3 to membranes correlates with hydrophobic modifications that are different in the membrane-bound and soluble forms of rab3. The results demonstrate the exclusive targeting of a small GTP-binding protein to secretory vesicles of a subset of the regulated pathway of secretion.