Comparison of manual and automatic segmentation methods for brain structures in the presence of space-occupying lesions: a multi-expert study.

The purpose of this work was to characterize expert variation in segmentation of intracranial structures pertinent to radiation therapy, and to assess a registration-driven atlas-based segmentation algorithm in that context. Eight experts were recruited to segment the brainstem, optic chiasm, optic nerves, and eyes, of 20 patients who underwent therapy for large space-occupying tumors. Performance variability was assessed through three geometric measures: volume, Dice similarity coefficient, and Euclidean distance. In addition, two simulated ground truth segmentations were calculated via the simultaneous truth and performance level estimation algorithm and a novel application of probability maps. The experts and automatic system were found to generate structures of similar volume, though the experts exhibited higher variation with respect to tubular structures. No difference was found between the mean Dice similarity coefficient (DSC) of the automatic and expert delineations as a group at a 5% significance level over all cases and organs. The larger structures of the brainstem and eyes exhibited mean DSC of approximately 0.8-0.9, whereas the tubular chiasm and nerves were lower, approximately 0.4-0.5. Similarly low DSCs have been reported previously without the context of several experts and patient volumes. This study, however, provides evidence that experts are similarly challenged. The average maximum distances (maximum inside, maximum outside) from a simulated ground truth ranged from (-4.3, +5.4) mm for the automatic system to (-3.9, +7.5) mm for the experts considered as a group. Over all the structures in a rank of true positive rates at a 2 mm threshold from the simulated ground truth, the automatic system ranked second of the nine raters. This work underscores the need for large scale studies utilizing statistically robust numbers of patients and experts in evaluating quality of automatic algorithms.

Psychological impact of news of genetic risk for Huntington disease.

A one-year longitudinal study was conducted investigating the psychological effects of the news of genetic testing for the Huntington disease (HD) gene. Participants were assessed at baseline (before obtaining news of test results) and at three, six, and 12 months after test results on stress-specific symptom measures. Among carriers of the HD gene, a considerable number (55%) showed evidence of neurological impairment at baseline, indicative of HD. Also noteworthy, these individuals had significantly higher psychological symptom scores at baseline than carriers without neurological impairment or noncarriers. Despite this, these individuals were no more aware of their carrier status at baseline than carriers without HD symptoms or noncarriers. Furthermore, the psychological symptom levels of HD carriers with neurological impairment remained elevated across the follow-up assessments. Results for noncarriers and carriers without HD neurological symptoms were consistent with the findings of previous studies indicating that news of genetic testing for the HD gene had limited detrimental impact. The clinical implications of the results are discussed.

Quantified power Doppler US of tumor blood flow correlates with microscopic quantification of tumor blood vessels.

PURPOSE: To evaluate the ability of a quantified power Doppler ultrasonography (US) system to help quantitate differences in tumor vascularity after radiation therapy and administration of tumor necrosis factor (TNF). MATERIALS AND METHODS: Murine glioblastoma tumors were grown in the thighs of two sets of 25 mice each. Each mouse was assigned to one of four treatment groups: control (no treatment), radiation therapy, TNF therapy, or combination therapy (both radiation and TNF therapies). Mice were then evaluated with quantified power Doppler US, and a vascularity index (color area) was calculated for different tumor regions in each group. The tumors were then excised, and histologic evaluation was performed by using an immunofluorescence-tagged monoclonal antibody against blood vessel endothelium. The number of stained blood vessels per high-power field was correlated with the sonographically determined vascularity index. RESULTS: The color area of the total tumor decreased to 37% of that in the control group in mice treated with radiation therapy alone (P: =.02), 26% of that in the control group in mice treated with TNF alone (P: =.05), and 8% of that in the control group in those treated with both TNF and radiation (P: =.006). These results correlated well with the quantified results from immunofluorescent staining (r = 0.98). CONCLUSION: Quantified power Doppler US is a noninvasive method for the evaluation of tumor vascularity and blood flow.

Risk factors for syphilis among incarcerated women in Rhode Island.

Syphilis remains a significant problem in the United States. The prison environment is an ideal location to identify and treat syphilis. We undertook this study to describe the correlates and risk factors for syphilis among incarcerated women in Rhode Island. The study design was a review of all cases of syphilis identified through routine screening in the state prison and a case control study. Between 1992 and 1998, among 6,249 incarcerated women, 86 were found to have syphilis; of these, 29 were primary and secondary cases representing 49% of infectious cases of syphilis in women in the state. The prison environment offers a unique opportunity for the diagnosis and treatment of syphilis.

Three-dimensional color Doppler sonography before and after fibroid embolization.

Three-dimensional color Doppler sonography was performed within 1 hour, 1 day, 3 months, and 6 months of fibroid embolization in 20 patients who had a total of 31 fibroids greater than 2 cm in average dimension. The greatest decrease in vascularity occurred 1 day after the procedure, whereas the greatest volume change was found at the 3 month follow-up examination. In about one half of the patients scanned, depiction of fibroid vascularity by color Doppler sonography was found to improve the delineation of the size, location, and extent of myometrial involvement. Hypervascular fibroids (12 of 31) tended to decrease in size after treatment more than isovascular (10 of 31) or hypovascular ones (9 of 31). Additional investigations that are similar to this one will be needed to determine if three-dimensional color Doppler sonography can be used to predict those who will be responders, partial responders, or nonresponders to embolotherapy.

Quantified color Doppler sonography of tumor vascularity in an animal model.

This study was designed to evaluate the accuracy of a system to quantitate tumor vascularity with amplitude (power) color Doppler sonography two- and three-dimensionally. The vascularity of 20 transplanted murine tumors was determined with quantitated amplitude color Doppler sonography both two- and three-dimensionally and compared to tumor vascularity estimated by histologic examination. Serial examinations were performed 15, 30, 45, and 60 min after the injection of the exotoxin CM-101 and saline solution to assess changes in tumor vascularity. Three-dimensional amplitude color Doppler sonography best depicted the overall vascularity of tumor when compared to histologic estimation of vessel density. However, neither two- nor three-dimensional amplitude color power angiography correlated well to the microvessel count, probably a reflection of the difference in the method for vessel quantification using sonographic versus histologic techniques. Three-dimensional amplitude Doppler sonography correlated better with counts of large vessels (> 100 microm) as opposed to small vessels (> 15 microm). Time-activity curves showed no difference in tumor flow at the times measured in the experimental group injected with CM-101 or when compared to saline solutions in either the peripheral or central portions of the tumor. This three-dimensional amplitude color Doppler sonographic system affords global quantification of tumor vascularity and flow that may, in turn, be useful in determining the probability of malignancy (by determination of branching patterns and vessel regularity) or tumor response or both to treatment.

Preview: Lyme disease vaccines.

Lyme disease is a tick-borne spirochetal disease that is common in Rhode Island. The OSP A based vaccine against Lyme disease that has been shown effective in animal models has now been tested by two manufacturers in thousands of people. The vaccines appear to be safe and effective. When the vaccines become available to physicians, there should be strong demand in Rhode Island, especially in the southern part of the state where there is a high degree of public awareness and experience with Lyme disease. Studies of tick populations support surveillance data that show a concentration of risk in Washington County with a trend of expansion inland. Patients who receive the vaccine should be alerted to the likelihood of local reaction and the less likely systemic effects. Additional patient education should include awareness of other tick-borne diseases such as babesiosis, chrlichiosis, and Rocky Mountain Spotted Fever that are not vaccine-preventable. Serologic testing for Lyme disease will be affected by the immune response to the vaccine. These vaccines have not yet been tested in children.

Entomologic index for human risk of Lyme disease.

An entomologic index based on density estimates of Lyme disease spirochete-infected nymphal deer ticks (lxodes scapularis) was developed to assess human risk of Lyme disease. The authors used a standardized protocol to determine tick density and infection in numerous forested sites in six Rhode Island towns. An entomologic risk index calculated for each town was compared with the number of human Lyme disease cases reported to the Rhode Island State Health Department for the same year. A strong positive relation between entomologic risk index and the Lyme disease case rate for each town suggested that the entomologic index was predictive of Lyme disease risk.

Mammography referral patterns among Rhode Island physicians.

In 1987, the Rhode Island Department of Health conducted a survey of Rhode Island primary care physicians to determine their attitudes and practices regarding breast cancer screening, particularly their use of clinical breast exam (CBE) and referral for screening mammography, and compared the data with information obtained from primary care physicians in the US in 1984 and 1989. The survey showed that the same percentage of Rhode Island physicians (71%) and physicians nationally (72%) agree with American Cancer Society (ACS) guidelines for breast cancer screening, but Rhode Island physicians refer for mammography (43 vs 37%) and perform CBE (97 vs 80%) according to ACS guidelines more frequently. Cost, reliability and availability were of greater concern to physicians nationally than in Rhode Island. Despite better use of breast cancer screening by Rhode Island physicians, only 43% reported referring for mammography according to guidelines. Since studies indicate that the recommendation of her physician is a key determinant of a woman's decision to have a screening mammogram, physician referral needs to increase in order to meet the Year 2000 Objectives of 80% for screening mammography for women 40 and older.

Neuropsychological impairment and associated intellectual functions in schizophrenic and other psychiatric patients.

As a routine admission procedure of an ongoing research program, the Halstead-Reitan Battery (HRB) and the Wechsler Adult Intelligence Scale (WAIS) were completed by 37 chronic schizophrenic patients, 3 patients with major affective disorders, and 2 with atypical psychoses. These admission data provided a basis for a retrospective investigation into the possibility of a relationship between impairment on the HRB and IQ. It was found that greater impairment on the HRB was associated with lower full-scale IQ (FSIQ) scores (r = -0.78, p less than .001). When the sample was separated into impaired and normal groups based on performance on the HRB, the coefficients of two discriminant functions, i.e., Verbal IQ and Picture Arrangement, classified the two groups with 100% accuracy. Cross-validation of the stepwise discriminant function analysis, using the jackknife procedure, resulted in a 98% hit rate. The results of the present study together with those of two other recent studies suggest that intellectual functions are critical interactive variables for interpreting the performance of chronic schizophrenic and other psychiatric groups on the HRB. Cautions to be observed in interpreting impaired and normal functioning in the context of intellectual functions are discussed.

Neurological and neuropsychological studies of patients with obsessive-compulsive disorder.

We studied 18 DSM-III diagnosed obsessive-compulsive disorder patients with the Halstead-Reitan Battery (HRB), EEGs, and CT scans. Results for the group as a whole were within the normal range; however two patients had abnormal EEGs and four showed average impairment ratings on the HRB high enough to suggest organic deficits. More than half of the subjects were impaired on the tactual performance test from the HRB suggesting a possible deficit in spatial perception. These data, however, do not define a single neuropsychological deficit nor do they replicate an earlier report of left frontal lobe dysfunction in obsessive-compulsive disorder. Cerebral CT scans in ten patients, including all those with EEG and average impairment rating abnormalities, showed VBR, asymmetry, and sulcal prominence measures indistinguishable from a matched group of nonpsychiatric control subjects.