In vivo measurement of T2 distributions and water contents in normal human brain

Using a 32-echo imaging pulse sequence, T2 relaxation decay curves were acquired from five white- and six gray-matter brain structures outlined in 12 normal volunteers. The water contents of white and gray matter were 0.71 (0.01) and 0.83 (0.03) g/ml, respectively. All white-matter structures had significantly higher myelin water percentages (signal percentage with T2 between 10 and 50 ms) than all gray-matter structures. The range in geometric mean T2 of the main peak for both white and gray matter was from 70 to 86 ms. T2 distributions from the posterior internal capsules and splenium of the corpus callosum were significantly wider (width is related to water environment inhomogeneity) than those from any other white- or gray-matter structures. Thus, quantitative measurement and analysis of T2 relaxation reveals differences in brain tissue water environments not discernible on conventional MR images. These differences may make short T2 components reliable markers for normal myelin.

Thymus in myasthenia gravis: comparison of CT and pathologic findings and clinical outcome after thymectomy

PURPOSE

To correlate computed tomographic (CT) appearance of the thymus with results from histologic examination of thymic tissue and clinical outcome in patients with generalized myasthenia gravis who underwent thymectomy.

MATERIALS AND METHODS

Forty-five patients with myasthenia gravis underwent CT of the thorax and thymectomy. Findings at clinical follow-up were available in all patients.

RESULTS

Twenty-six patients had normal CT findings, seven had a diffusely enlarged thymus, and 12 had a focal mass. The results of histologic examination showed that 16 of 26 patients with normal CT findings had normal thymic tissue and 10 had lymphoid follicular hyperplasia; all seven patients with an enlarged thymus had lymphoid hyperplasia. Five of 12 patients with a focal mass at CT had lymphoid hyperplasia, and seven had thymoma. Clinical improvement following thymectomy was observed in 27 (93%) of 29 patients with lymphoid hyperplasia or thymoma and 11 (69%) of 16 patients with normal histologic examination (P < .03, chi(2) test).

CONCLUSION

The presence of an enlarged thymus or a focal mass in patients with myasthenia gravis indicates lymphoid hyperplasia or thymoma. However, CT is of limited value in distinguishing lymphoid follicular hyperplasia from a normal thymus or thymoma and in predicting clinical outcome.

Ovulatory premenopausal women lose cancellous spinal bone: a five year prospective study

Healthy premenopausal women with regular cycles are believed to be increasing or maintaining bone density. However, few studies have prospectively documented spinal cancellous bone, the bone that changes rapidly in response to reproductive hormones, in this population. Furthermore, our previous one-year study documented that 24% of the one-year bone change by quantitative computed tomography (QCT) was related to subclinical ovulatory disturbances (short luteal phase and non-ovulation) in the presence of regular menstrual cycles. The purpose of this study was to document the cancellous bone change over five years in this initially ovulatory, premenopausal cohort of 66 healthy women. Thirty-seven women, who continued to be premenopausal and have regular cycles, completed this five-year study. Those enrolled differed only by being older and weighing less than those who could not be contacted (n = 19) or who declined to participate (n = 10). Documentation of current ovulatory characteristics was obtained for at least three cycles in 27 women. At the five-year assessment, the volunteers were 40.6 (range 26-47) years old, weighed 58.5 (41-77) kg, and were 160.9 (149-174) cm in height. All were premenopausal, healthy, nonsmokers with regular menstrual cycles (mean 27.7, range 24-33 days). Six women with intervening events (such as pregnancy or use of oral contraceptives) had interval (12 to 60 months) QCT changes similar to the remaining 31 (-7.98 vs. -4.92 mg/cm, p = 0.1, respectively). Mean five-year QCT was 143.0 +/- 20.2 mg/cm, whereas the initial mean value was 151.9 +/- 20.1 mg/cm. Significant QCT loss over five years (-8.9 +/- 6.2 mg/cm) (95% Cl -6.9 to -11.0) correlated with QCT change in the first year (r = 0.629, p < 0.001). First-year change was not related to the subsequent four-year interval change (r = -0.056, p = 0.74), however. Five-year QCT change was not related to age, weight, osteoporosis family history, estimated calcium intake, or exercise, but did correlate with year one luteal index (luteal/cycle length) (r = 0.339, p = 0.043). Significant cancellous spinal bone loss occurs in healthy, ovulatory premenopausal women, and is influenced by subclinical disturbances of ovulation.

Maternal smoking during pregnancy and the risk of congenital urinary tract anomalies

To study maternal smoking during pregnancy and the risk of congenital urinary tract anomalies, we interviewed mothers of 118 affected infants born to residents of western Washington State during 1990 and 1991 and mothers of 369 control infants randomly selected from those without birth defects delivered during those years in five hospitals in King County, Washington. Maternal smoking was associated with an increased risk of congenital urinary tract anomalies in offspring (adjusted odds ratio [OR] = 2.3; 95% confidence interval [CI] = 1.2, 4.5). This risk was higher among light smokers (1-1000 cigarettes during the pregnancy) (OR = 3.7; 95% CI = 1.7, 8.6) than among heavy smokers (OR = 1.4; 95% CI = 0.6, 3.3). Our results corroborate previous findings and support the hypothesis of a causal relation.

Score for neonatal acute physiology: validation in three Kaiser Permanente neonatal intensive care units

BACKGROUND

Measurement of the severity of illness is a research area of growing importance in neonatal intensive care. Most severity of illness scales have been developed in tertiary care settings. Their applicability in community neonatal intensive care units has not been tested.

OBJECTIVES

Our goal was to assess the operational characteristics of the score for neonatal acute physiology (SNAP): the relationship to birth weight, the length of total hospital stay, and in-hospital mortality.

METHODS

We assigned SNAP scores prospectively to all inborn admissions at three community neonatal intensive care units during an 11-month period. Data on other neonatal predictors (eg, birth weight and the presence of congenital heart disease) were also collected. We measured in-hospital mortality, the experience of interhospital transport to a higher level of care, and total hospital stay.

RESULTS

We found that the SNAP's relationship to birth weight was similar to previous reports. The SNAP's perinatal extension is a reliable predictor of newborn in-hospital mortality, with an area under the receiver operator characteristic curve of 0.95. The SNAP is also a good predictor of total hospital length of stay, whether by itself (by which it can explain 31% of the total stay) or in combination with other variables. Its predictive ability is better among infants of low birth weight (<2500 g) than among those of normal birth weight (> or = 2500 g). The SNAP's predictive power was most limited among infants admitted to rule out sepsis. The predictive ability of a model containing birth weight, the SNAP, and transport status was not improved by the inclusion of two major diagnostic categories, the presence of congenital heart disease or complex illness.

CONCLUSION

Although it has definite limitations among infants who weight 2500 g or more, the SNAP is a potent tool for outcomes research. Modification of some of its parameters could result in a multifunctional scale suitable for use with all birth weights.

Electric blanket use during pregnancy in relation to the risk of congenital urinary tract anomalies among women with a history of subfertility

To study the potential effect of prenatal exposure to electromagnetic fields on the occurrence of cogenital urinary tract anomalies (CUTAs) in offspring, we conducted a case-control study in western Washington State. CUTA cases without known chromosomal abnormalities were identified from the Washington Birth Defects Registry. Controls without birth defects were randomly selected from among infants born in five large hospitals in King County, WA. Mothers of cases and controls were interviewed to obtain information on prenatal use of electric blankets, electrically heated water beds, and video display terminals. After adjustment for potential confounders, the risk of CUTAs was found not to be materially associated with these prenatal exposures among all subjects. Among women with a history of subfertility, however, prenatal use of electric blankets was associated with a more than four-fold increase in the risk of CUTAs [adjusted odds ratio (OR) = 4.4; 95% confidence interval (CI) = 0.9-22.7]. The risk was greater if the exposure occurred during the first trimester (adjusted OR = 10.0; 95% CI = 1.2-85.5). The risk also appeared to increase with increasing duration of electric blanket use. Despite small numbers and the potential for recall bias, our study indicates that identifying a susceptible population may be required for detecting adverse reproductive effects of electromagnetic fields.

Periconceptional multivitamin use in relation to the risk of congenital urinary tract anomalies

To study the relation of maternal periconceptional vitamin use to the risk of a congenital urinary tract anomaly (CUTA), we conducted a case-control study using the Washington State Birth Defect Registry. We identified CUTA cases with no known chromosomal abnormality in seven counties in western Washington State occurring between January 1, 1990, and December 31, 1991. We randomly selected a sample, as controls, of all infants delivered in five large hospitals in King County who did not have a birth defect and who were born in the same year as the cases. About 55% of all infants in King County and a smaller proportion of infants in the other six counties are delivered in these five hospitals. We interviewed mothers of 118 cases and 369 controls to obtain information about their vitamin use during the pregnancy and during the year before the conception. After adjustment for maternal race, family income, county of maternal residence, and birth year, we found that women who used multivitamins during the first trimester had only 15% the risk of bearing a child with a CUTA compared with women who did not take vitamins [odds ratio (OR) = 0.15; 95% confidence interval (CI) = 0.05-0.43]. The reduction was smaller for use restricted to the second or third trimesters (OR = 0.31; 95% CI = 0.09-1.02). Among women who used vitamins during the first trimester, vitamin use before conception was not associated with any further reduction in the risk, nor did there appear to be an association with the amount or brand of vitamin used.(ABSTRACT TRUNCATED AT 250 WORDS)

Oral contraceptive use after conception in relation to the risk of congenital urinary tract anomalies

The authors conducted a case-control study of the relation of OC use after conception to the occurrence of congenital urinary tract anomalies (CUTAs). Singleton CUTA cases with no known chromosomal abnormality from seven counties in western Washington State born during the period January 1, 1990-December 31, 1991 were identified through the Washington State Birth Defect Registry. Controls without birth defects were randomly selected from singleton births that occurred in the same year as the cases in five large hospitals in King County. Mothers of the 118 cases and 369 controls were interviewed to obtain their contraceptive history as well as other information. Mothers of nine cases (7.6%) and eight controls (2.2%) had taken OCs at some time during the pregnancy. After adjustment for birth year and county of maternal residence, OC use after conception was associated with an almost five-fold increased risk of having a baby with a CUTA [odds ratio (OR) = 4.8, 95 percent confidence interval (CI), 1.6-14.1] relative to no contraception at or after conception. Use of other contraceptive methods after conception was not related to the risk of CUTAs. OC use during the 3 or 6 months prior to the conception also was not associated with the risk of CUTAs. Further adjustment for sociodemographic factors, reproductive history, perinatal exposure to exogenous agents, and past OC use did not change the results, nor did restricting the analysis to residents of King County.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance imaging in the evaluation of clinical trials in multiple sclerosis

Magnetic resonance imaging (MRI) provides an objective method of evaluating multiple sclerosis clinical trials and is at least five times more sensitive to disease activity. In a recent clinical trial, MRI was also approximately twice as sensitive as clinical measurements to the treatment effect of a drug.

Maternal prior pregnancy loss and the sex ratio among infants with sudden infant death syndrome

It has been reported that the offspring of human leukocyte antigen (HLA)-compatible parents may have a high male/female sex ratio. To study the hypothesis that parental HLA compatibility is related to sudden infant death syndrome (SIDS), I conducted a population-based case-control study using 1982-1990 linked Washington State birth and death certificate data to compare the sex ratio of SIDS cases and controls. SIDS cases were identified by the International Classification of Diseases, 9th revision, CM code 798.0, on the death certificate, and four controls born in the same year as the case were randomly selected for each case. I categorized the infants according to maternal parity and history of pregnancy loss. There was a high risk of SIDS in males relative to females among first liveborn infants whose mothers had had two or more prior pregnancy losses (odds ratio = 7.6, 95% confidence interval = 1.5-39). I had hypothesized a priori that this group would have the largest proportion of infants of HLA-compatible parents. No similar association was observed among infants with a prior liveborn sibling. In addition to the findings from two previous studies, this finding provides further evidence that parental HLA compatibility may be related to the risk of SIDS in offspring.

Concordance of parental race/ethnicity in relation to the risk of sudden infant death syndrome (SIDS)

It has been reported that parental human leukocyte antigen (HLA) compatibility is associated with certain adverse reproductive outcomes such as multiple spontaneous fetal losses and malformations, particularly among women without a prior livebirth. In order to study the relation between parental HLA compatibility and the risk of SIDS, a population-based case-control study was conducted using 1982-1990 Washington State linked birth and death certificate data. Concordance of parental race/ethnicity combined with prior maternal fetal loss was used as surrogate measures of parental HLA compatibility. The relation was evaluated separately among infants with and without a prior live-born sibling. Among first liveborn infants, those of racially discordant parents were at reduced risk of SIDS compared with those of racially concordant parents (relative risk [RR] = 0.57, 95% confidence interval = 0.34-0.96). Infants of white-minority parents were all at lower risk of SIDS than infants of white-white parents. Infants of racially concordant parents with two or more prior fetal losses were at increased risk of SIDS (RR = 2.44, 1.07-5.56), relative to infants of racially discordant parents. No such associations were observed among infants with prior live-born siblings. In fact, in this latter population, infants of racially concordant parents tended to have a lower risk of SIDS than those of discordant parents. This study suggests that a portion of SIDS cases, particularly among first live-born infants, may be due to parental HLA sharing. However, final determination of the existence of this relationship requires actual HLA typing of parents of both cases and controls.

The use of magnetic resonance imaging in monitoring interferon therapy of multiple sclerosis

Magnetic resonance imaging (MRI) was used to evaluate the efficacy of systemic lymphoblastoid interferon therapy in chronic progressive multiple sclerosis. The clinical outcome of this trial has been reported previously. Thirty-six patients with chronic progressive multiple sclerosis were treated with interferon daily for 6 months and 27 received placebo. Patients had MRI at the outset of the study and after 6 and 24 months. Lesion activity and changes in lesion load were determined. As the study progressed, both the interferon- and the placebo-treated group developed more active lesions. There was no difference in lesion activity between the two groups. Comparison of lesion load, however, showed a trend toward improvement after 6 months for the interferon-treated group. This difference between the two groups had disappeared by the end of the study. We conclude that lymphoblastoid interferon was not effective in decreasing active MRI-detected lesions or in decreasing MRI lesion load in patients with chronic progressive multiple sclerosis.

Interferon beta-1b is effective in relapsing-remitting multiple sclerosis. II. MRI analysis results of a multicenter, randomized, double-blind, placebo-controlled trial. UBC MS/MRI Study Group and the IFNB Multiple Sclerosis Study Group

We performed yearly MRI analyses on 327 of the total 372 patients in a multicenter, randomized, double-blind, placebo-controlled trial of interferon beta-1b (IFNB). Clinical results are presented in the preceding companion paper. Baseline MRI characteristics were the same in all treatment groups. Fifty-two patients at one center formed a cohort for frequent MRIs (one every 6 weeks) for analysis of disease activity. The MRI results support the clinical results in showing a significant reduction in disease activity as measured by numbers of active scans (median 80% reduction, p = 0.0082) and appearance of new lesions. In addition, there was an equally significant reduction in MRI-detected burden of disease in the treatment as compared with placebo groups (mean group difference of 23%, p = 0.001). These results demonstrate that IFNB has made a significant impact on the natural history of MS in these patients.

The effect of parity on the relation between maternal history of spontaneous pregnancy loss and the risk of sudden infant death syndrome in offspring

We conducted a population-based case-control study, using the 1984-1989 linked Washington State birth and death certificate data, to determine whether maternal prior spontaneous pregnancy loss was associated with the risk of sudden infant death syndrome (SIDS). We identified 872 autopsied SIDS cases and 3,704 controls matched to cases on year of birth. To reduce the confounding from unmeasured socioeconomic and behavioral factors, we analyzed the data separately for infants with and without father's race provided on the birth certificate. Among infants whose father's race was known, those of multiparous women with a prior spontaneous pregnancy loss before 20 weeks gestational age were at reduced risk of SIDS, after adjustment for maternal age, prenatal smoking,a nd gravidity. An increased number of prior pregnancy losses was associated with a further reduction in the risk of SIDS: one prior pregnancy loss was associated with a 25% decrease [odds ratio (OR) = 0.75; 95% confidence interval (CI) = 0.52-1.08], and two or more prior pregnancy losses was associated with a 47% decrease (OR = 0.53; 95% CI = 0.30-0.94). There was no such association, however, among infants of women with no prior livebirth. Similar associations were observed between prior spontaneous pregnancy loss during the entire gestational period and the risk of SIDS in offspring. To explain the different associations between maternal prior pregnancy loss and the risk of SIDS observed among infants of women with and without a prior livebirth, we hypothesize an upward bias resulting from the presence of a larger proportion of infants of human leukocyte antigen-compatible couples among first liveborn infants.

Structural brain imaging abnormalities associated with schizophrenia and partial trisomy of chromosome 5

Chromosomal abnormalities occurring in association with mental illness provide a unique opportunity to study the interaction of genetic abnormalities and the brain in mental illness. Four individuals from a family in which schizophrenia was found to cosegregate with a partial trisomy of chromosome 5 were studied with computed tomography and magnetic resonance imaging. Temporal lobe atrophy was found in the two trisomic males and in the asymptomatic balanced translocation female. In addition, a large cavum septum pellucidum and a cavum vergae were found in the older trisomic individual. Scans from the normal male were free of abnormalities. These results suggest that molecular studies of the translocation breakpoints in this chromosomal abnormality may be of interest, and encourage further studies of brain structure in other chromosomal abnormalities associated with psychosis.

Maternal smoking, low birth weight, and ethnicity in relation to sudden infant death syndrome

To determine independent effects of maternal smoking and infant low birth weight (less than 2,500 g) on risk of sudden infant death syndrome (SIDS) among different ethnic groups, the authors conducted a population-based case-control study based on the 1984-1989 Washington State birth record data. Two control groups were selected for 916 SIDS cases. The first one comprised 3,704 randomly selected controls, matched to cases by birth year, to describe the characteristics of the study population. In the second control group (n = 6,186), minorities were oversampled, by matching to cases on maternal race/ethnicity and birth year, to increase the power of analysis within each ethnic group. All subjects were classified into five groups on the basis of maternal race/ethnicity: white, black, American Indian, Asian, and Hispanic. After controlling for confounders, the authors found that maternal smoking was independently associated with SIDS among white (odds ratio (OR) = 2.2, 95% confidence interval (CI) 1.8-2.6), blacks (OR = 3.1, 95% CI 1.7-5.9), Asians (OR = 2.7, 95% CI 1.1-6.6, and Hispanics (OR = 5.5, 95% CI 1.4-22.0), but had little relation among American Indians (OR = 1.4, 95% Cl 0.9-2.4). Infant low birth weight was independently related to SIDS among whites (OR = 2.5, 95% Cl 1.8-3.4) and American Indians (OR = 5.5, 95% Cl 2.8-11.2) and to a lesser extent among blacks (OR = 1.9, 95% Cl 0.8-4.1), but not among Asians (OR = 1.1, 95% Cl 0.2-5.2) or Hispanics (OR = 1.2, 95% Cl 0.1-11.5). The misclassification that may occur because of the application of the same definition of low birth weight to all ethnic groups may be the main reason for the weaker association between infant low birth weight and SIDS among blacks and the absence of an association among Asians and Hispanics. Defining low birth weight as below population mean minus 1.96 standard deviations may provide better insight into the relation between low birth weight and SIDS. Understanding the reasons for the lack of a strong association between maternal smoking during pregnancy and SIDS among American Indians may enhance our knowledge of the etiology and pathogenesis of SIDS.

Evaluation of cartilage lesions by magnetic resonance imaging at 0.15 T: comparison with anatomy and concordance with arthroscopy

Recent evidence suggests that pharmacological treatment may alter the rate of progression of cartilage damage in osteoarthritis (OA). However, a lack of accurate and precise noninvasive assessments of cartilage structure makes it difficult to answer this question directly with prospective clinical trials, prevents early diagnosis of OA and restricts assessment of treatment to evaluation of symptoms or joint function. It is important, therefore, to develop precise, noninvasive methods both for diagnosis of early OA before damage is extensive and irreversible and for evaluation of therapeutic effectiveness. Magnetic resonance imaging (MRI) allows for noninvasive, multiplanar body imaging which depends on proton density, flow, and the T1 and T2 relaxation times. Because these variables differ markedly among joint tissues, cartilage erosions are visible with MRI and it should be possible to quantify them. Our objective was to compare MRI with arthroscopy for assessing the depth of lesions in the articular cartilage of human knees to help develop and validate MRI for use in clinical trials designed to assess the effect of therapy on cartilage structure. In the first part of our study, the effect of the MRI pulse sequence variables on the images was evaluated by varying them systematically and comparing the anatomy seen with MRI with that seen at arthroscopy or arthrotomy and with the histology. In the second part, 31 patients were assessed with MRI before arthroscopy. The MRI were graded on a 4-point ordinal scale by 2 observers who were unaware of the clinical diagnosis and compared with findings at arthroscopy which were graded using the same scale.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance imaging of the head in the diagnosis of multiple sclerosis: a prospective 2-year follow-up with comparison of clinical evaluation, evoked potentials, oligoclonal banding, and CT

We previously compared the diagnostic capabilities of MRI of the head with CT, evoked potentials, and CSF oligoclonal banding (OB) analysis in a prospective evaluation of 200 patients with suspected multiple sclerosis (MS). To examine the ability of MRI and other paraclinical tests to predict the diagnosis of clinically definite MS (CDMS), we did a systematic clinical follow-up of 200 patients who were previously reported. In that study, 85 of 200 could be diagnosed as having laboratory-supported definite MS (LSDMS). In follow-up, we excluded one patient diagnosed as LSDMS who in retrospect was considered to have had CDMS at entry and 15 patients who were eventually diagnosed as having other diseases. After a mean follow-up of 2.1 years, 55 of the remaining 184 patients (30%) had developed CDMS. Thirty-eight of 84 patients with an original diagnosis of LSDMS (45%) and 17 of the remaining 100 patients with suspected MS (17%) had become CDMS. Forty-six of the 55 patients who developed CDMS in follow-up (84%) had an initial MRI that was strongly suggestive of MS. Fifty-two of those 55 CDMS patients (95%) had at least one MS-like abnormality on MRI when originally studied. In contrast, 38 of 55 (69%) had CSF OB, 38 of 55 (69%) had an abnormal VEP, 35 of 55 (64%) had an abnormal SEP, and 21 of 55 (38%) had an abnormal CT when first studied. MRI was the most sensitive single paraclinical test for predicting CDMS. CDMS developed during follow-up in 46 of the 94 patients (49%) whose initial MRI was strongly suggestive of MS.(ABSTRACT TRUNCATED AT 250 WORDS)

Glomus of the choroid plexus: the normal spin-echo appearance on magnetic resonance imaging

The glomus of the choroid plexus is located within the trigone of the lateral ventricles. The magnetic resonance images of the choroid plexus in 624 patients of all ages were reviewed and graded to determine the variation of the appearance of the glomus of the choroid plexus as seen on T2-weighted spin echo (SE). With the moderately T2-weighted SE sequences the intensity of the choroid plexus signal was equal to, or less than, that from deep cerebral grey matter in 76% of patients and greater than that from deep cerebral grey matter in 23%; in 1% of patients the glomus of the choroid plexus was "cyst-like". In all 100 patients studied with the heavily T2-weighted SE sequence the intensity of the choroid plexus signal was greater than that from the deep cerebral grey matter. The variation in the normal appearance of the glomus of the choroid plexus is consistent with known histologic changes described in the literature. The importance of recognizing the glomus of the choroid plexus and not mistaking it for other normal anatomical structures or diseases is evident.