Biomedical subjects

Inkyung Jung

Publications and source records attributed to Inkyung Jung.

4 recordsLinked to original sources

PubMed2007

A spatial scan statistic for ordinal data.

Spatial scan statistics are widely used for count data to detect geographical disease clusters of high or low incidence, mortality or prevalence and to evaluate their statistical significance. Some data are ordinal or continuous in nature, however, so that it is necessary to dichotomize the data to use a traditional scan statistic for count data. There is then a loss of information and the choice of cut-off point is often arbitrary. In this paper, we propose a spatial scan statistic for ordinal data, which allows us to analyse such data incorporating the ordinal structure without making any further assumptions. The test statistic is based on a likelihood ratio test and evaluated using Monte Carlo hypothesis testing. The proposed method is illustrated using prostate cancer grade and stage data from the Maryland Cancer Registry. The statistical power, sensitivity and positive predicted value of the test are examined through a simulation study.

Cluster Analysis↗

PubMed2006

Prospective changes in quality of life after ductal carcinoma-in-situ: results from the Nurses' Health Study.

PURPOSE: The incidence of ductal carcinoma-in-situ (DCIS) of the breast has been increasing. However, uncertainties exist about its prognosis, optimal treatment, and effect on women's health-related quality-of-life (HRQoL). Our study assessed the prospective changes in HRQoL in women diagnosed with DCIS. PATIENTS AND METHODS: Between 1992 and 2000, HRQoL was assessed at three 4-year intervals among women enrolled in two Nurses' Health Study cohorts using the Medical Outcomes Survey Short-Form 36 health survey. Using mixed effects and logistic regression modeling, we compared the prospective changes in HRQoL scores among women with and without DCIS. RESULTS: The study included 114,728 women; 510 were diagnosed with DCIS during the study period. During 4 years, women with DCIS had small, but statistically significantly greater declines in the domains of role limitations due to physical problems (-6.74; SE, 1.69), vitality (-2.06; SE, 0.78), and social functioning (-2.40; SE, 0.93) than women without DCIS. Among those with DCIS, clinically significant declines were more often observed within 6 months of the diagnosis in the domains of social functioning (odds ratio, 1.78; 95% CI, 1.03 to 3.07) and mental health (odds ratio, 2.03; 95% CI, 1.09 to 3.79) than after 6 months after diagnosis. CONCLUSION: Women with DCIS experienced small long-term declines in HRQoL, although these declines did not seem to be clinically important. Short-term clinically significant declines in the psychosocial domains were noted. In counseling women with DCIS, clinicians should provide reassurance but prepare them to deal with the short-term sequelae.

Adult↗

PubMed2005

Analyzing attributes of vessel populations.

Almost all diseases affect blood vessel attributes (vessel number, radius, tortuosity, and branching pattern). Quantitative measurement of vessel attributes over relevant vessel populations could thus provide an important means of diagnosing and staging disease. Unfortunately, little is known about the statistical properties of vessel attributes. In particular, it is unclear whether vessel attributes fit a Gaussian distribution, how dependent these values are upon anatomical location, and how best to represent the attribute values of the multiple vessels comprising a population of interest in a single patient. The purpose of this report is to explore the distributions of several vessel attributes over vessel populations located in different parts of the head. In 13 healthy subjects, we extract vessels from MRA data, define vessel trees comprising the anterior cerebral, right and left middle cerebral, and posterior cerebral circulations, and, for each of these four populations, analyze the vessel number, average radius, branching frequency, and tortuosity. For the parameters analyzed, we conclude that statistical methods employing summary measures for each attribute within each region of interest for each patient are preferable to methods that deal with individual vessels, that the distributions of the summary measures are indeed Gaussian, and that attribute values may differ by anatomical location. These results should be useful in designing studies that compare patients with suspected disease to a database of healthy subjects and are relevant to groups interested in atlas formation and in the statistics of tubular objects.

Cerebral Arteries↗

PubMed2004

Abnormal vessel tortuosity as a marker of treatment response of malignant gliomas: preliminary report.

Despite multiple advances in medical imaging, noninvasive monitoring of therapeutic efficacy for malignant gliomas remains problematic. An underutilized observation is that malignancy induces characteristic abnormalities of vessel shape. These characteristic shape abnormalities affect both capillaries and much larger vessels in the tumor vicinity, involve larger vessels prior to sprout formation, and are generally not present in hypervascular benign tumors. Vessel shape abnormalities associated with malignancy thus may appear independently of increase in vessel density. We hypothesize that an automated, computerized analysis of vessel shape as defined from high-resolution MRA can provide valuable information about tumor activity during the treatment of malignant gliomas. This report describes vessel shape properties in 10 malignant gliomas prior to treatment, in 2 patients in remission during treatment, and in 2 patients with recurrent disease. One subject was scanned multiple times. The method involves an automated, statistical analysis of vessel shape within a region of interest for each tumor, normalized by the values obtained from the vessels within the same region of interest of 34 healthy subjects. Results indicate that untreated tumors display statistically significant vessel tortuosity abnormalities. These abnormalities involve vessels not only within the tumor margins as defined from MR but also vessels in the surrounding tissue. The abnormalities resolve during effective treatment and recur with tumor recurrence. We conclude that vessel shape analysis could provide an important means of assessing tumor activity.

Cerebrovascular Circulation↗