Biomedical subjects

Christian Ritter

Publications and source records attributed to Christian Ritter.

7 recordsLinked to original sources

PubMed2006

Absolute quantification of myocardial perfusion under adenosine stress.

The prebolus technique allows one to quantify perfusion in the human heart with a low variability by means of MRI. In this study the prebolus technique was used to determine quantitative perfusion values in the human heart under adenosine stress and to measure the myocardial perfusion reserve (MPR). Twelve healthy volunteers were examined using the multislice prebolus technique with 1/4 cc Gd-BOPTA. Signal intensity (SI) time courses were evaluated in 288 manually segmented sectors at rest and stress. Myocardial perfusion was determined by deconvolution of the SI time courses with the arterial input function (AIF) from the prebolus scan. The mean stress perfusion value was 1.78 +/- 0.53 cc/g/min, and the mean rest perfusion was 0.52 +/- 0.11 cc/g/min, resulting in a mean MPR of 3.59 +/- 1.26. The measured values correlate well with data from animal models and human positron emission tomography (PET) studies.

Adenosine↗

PubMed2006

Crisis intervention team training for police officers responding to mental disturbance calls.

OBJECTIVES: In recognition of the fact that police are often the first responders for individuals who are experiencing a mental illness crisis, police departments nationally are incorporating specialized training for officers in collaboration with local mental health systems. This study examined police dispatch data before and after implementation of a crisis intervention team (CIT) program to assess the effect of the training on officers' disposition of calls. METHODS: The authors analyzed police dispatch logs for two years before and four years after implementation of the CIT program in Akron, Ohio, to determine monthly average rates of mental disturbance calls compared with the overall rate of calls to the police, disposition of mental disturbance calls by time and training, and the effects of techniques on voluntariness of disposition. RESULTS: Since the training program was implemented, there has been an increase in the number and proportion of calls involving possible mental illness, an increased rate of transport by CIT-trained officers of persons experiencing mental illness crises to emergency treatment facilities, an increase in transport on a voluntary status, and no significant changes in the rate of arrests by time or training. CONCLUSIONS: The results of this study suggest that a CIT partnership between the police department, the mental health system, consumers of services, and their family members can help in efforts to assist persons who are experiencing a mental illness crisis to gain access to the treatment system, where such individuals most often are best served.

Communication↗

PubMed2006

The making of health:: a reflection on the first 10 years in the life of a journal.

This introduction to the Tenth Anniversary Issue surveys articles that have been published in health: since its launch. Reviewing the original aims of the journal, the editors discuss some of the main issues that authors have raised, both about health and illness. Focusing upon articles that have been published in this particular journal, we discuss the way that new medical technologies--particularly global ones--have shaped ideas about disease and its treatment, and in consequence about what 'good health' should be. Related to the growth in medical and other technology--not least the rise of the Internet during the life of this journal--is the number of articles that discuss the rights of patients and the establishment of what might be termed an 'illness culture'. We conclude that there continues to be more to health than it being the background to illness or disease, and ask the question: should the 'taken for grantedness' of health be taken for granted any longer?

Anniversaries and Special Events↗

PubMed2006

Different reconstruction intervals for exclusion of coronary artery calcifications by retrospectively gated MDCT.

OBJECTIVE: Exclusion of coronary artery calcifications has a high negative predictive value for the diagnosis of coronary artery disease. However, it is known that significant differences in calcium scoring can occur because of the ECG trigger interval. Thus, the aim of the study was to evaluate the influence of different reconstruction intervals on detection of any coronary calcium by using MDCT and retrospective cardiac gating. CONCLUSION: For a true exclusion of coronary artery calcifications, different reconstruction intervals have to be evaluated.

Calcinosis↗

PubMed2005

Depression in family medicine faculty.

BACKGROUND AND OBJECTIVES: Depression among family medicine faculty may contribute to decreased effectiveness in patient care, decreased effectiveness in teaching, and career changes. The present study determined the nationwide prevalence of depression and related risk factors among family medicine residency program faculty. METHODS: All full-time US family medicine faculty, program directors, and behavioral scientists listed as members of the Society of Teachers of Family Medicine in October 2000 were surveyed. The survey included demographics, clinical practice characteristics, the Beck Depression Inventory II, the Social Readjustment Rating Scale (SRRS), and a scale to measure stress within the residency program. RESULTS: Surveys were completed by 1,418 faculty members. Seven percent of survey respondents scored mildly depressed, and 5% scored moderately to severely depressed. Seven percent of respondents scored highly stressed on the SRRS. Significant predictors of depression scores included being single, being a member of an underrepresented minority group, having increased stress scores, and having a greater amount of time devoted to teaching. CONCLUSIONS: Program directors and department chairs need to be aware of the prevalence of depression among faculty, since it may affect their performance of patient care and teaching responsibilities.

Demography↗

PubMed2004

Correction for partial volume errors in MR heart perfusion imaging.

Myocardial MR first-pass perfusion time courses are contaminated by signals from the ventricles (spillover) as a consequence of partial volume effects and motion. An early increase in the signal intensity from the myocardium is an indicator of contamination. This contamination leads to under- or overestimation of perfusion, depending on the amount of contamination. In this work a simple method for contamination correction is proposed: curves proportional to the signal intensity time courses in the ventricles are subtracted from the signal intensity time courses in the myocardium to minimize the variance of signal before the arrival of the contrast medium in the myocardium. The proposed correction is easy to apply, removes the contamination, and leads to more precise perfusion values.

Artifacts↗

PubMed2004

Prebolus quantitative MR heart perfusion imaging.

The purpose of this study was to present the prebolus technique for quantitative multislice myocardial perfusion imaging. In quantitative MR perfusion studies the maximum contrast agent dose is limited by the requirement to determine the arterial input function (AIF). The prebolus technique consists of two consecutive contrast agent administrations. The AIF is determined from a first low-dose bolus, while a second, high-dose bolus allows the measurement of the myocardium with improved signal increase. The results of the prebolus technique using a multislice saturation recovery trueFISP sequence in healthy volunteers are presented. In comparison to a standard dose of 3 ml Gd-DTPA, perfusion values are maintained while the signal increase in the concentration time courses was considerably improved, accompanied by reduced standard deviations of the obtained perfusion values (0.72 +/- 0.13 ml/g/min for 1 ml/8 ml and 0.67 +/- 0.10 ml/g/min for 1 ml/12 ml Gd-DTPA, respectively).

Adult↗