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Urinary bladder neck blood flow: comparison of transrectal color Doppler ultrasound to laser Doppler flowmetry
Abstracts margins on US images, and then consensus was established. The statistical analysis was performed with t-Test. Results: THI improved contrast in 55% of cases and visualization of margins of adrenal masses in 40% of cases. In 4% of cases, the quality of visualization of adrenal mass with THI was worse (cases of right adrenal masses in patients with fatty liver), but SonoCT improved visualization of adrenal mass (contrast and margins) in these cases. SonoCT improved contrast in 57% of cases and improved delineation of adrenal mass margins in 52% of cases. There was no statistical correlation (␣⬎0.05) between patient’s BMI and the improvement of visualization of adrenal mass (contrast or margins) by THI or SonoCT. Conclusions: Novel ultrasound techniques as THI and SonoCT improve the visualization of adrenal masses (their contrast and margins) irrespectively of patient’s constitution described by patient’s BMI. SonoCT in contrast to THI may improve visualization of right-sided adrenal masses in patients with fatty liver. 31879 Urinary bladder neck blood flow: Comparison of transrectal color Doppler ultrasound to laser Doppler flowmetry Schuster A,*1,3 Pinggera GM,3 Pallwein L,2 Frauscher F,2 Strasser H,3 Bartsch G,3 zur Nedden D,2 1. Radiology, LKH Feldkirch, Feldkirch, Austria, 2. Department of Radiology, University Hospital Innsbruck, Innsbruck, Austria, and 3. Department of Urology, University Hospital Innsbruck, Innsbruck, Austria Objective: The purpose of this study was to assess the accuracy of transrectal color Doppler ultrasound (TRCDUS) to measure relative changes of urinary bladder neck blood flow. For this reason, TRCDUS measurements were compared with laser Doppler flowmetry (LDF), the “gold standard,” in an animal model. Methods: TRCDUS and LDF of the urinary bladder were performed in three anesthetized pigs during comparative cystometry. Normal saline (NaCl) was used for the first run, followed by a second run with 0.2-M potassium chloride (KCl). Standard urodynamic parameters were recorded in each run. Peak systolic velocity (PSV) and end-diastolic velocity (EDV) were measured in several vessels of the bladder neck at filling volumes of 0 ml, 100 ml, and maximum bladder capacity. Tissue perfusion units (TPU) were measured using a BLF21 laser Doppler flowmeter (Transonic Systems® Inc., USA). Results: During filling with NaCl, mean PSV increased from 15.1 cm/s to 22.3 cm/s and 40.8 cm/s, whereas with KCl filling, mean PSV increased from 15.1 cm/s to 40.6 cm/s and 46.9 cm/s. Mean EDV increased from 3.3 cm/s to 6.25 cm/s and 12.9 cm/s during NaCl filling, whereas with KCl an increase from 3.3 cm/s to 12.2 cm/s and 16.4 cm/s was seen. With NaCl filling, bladder neck blood flow increased from 22 TPU to 46 TPU and 62.5 TPU, compared to 50 TPU and 102.5 TPU with KCl. Conclusions: TRCDUS and LDF showed a corresponding increase of urinary bladder neck perfusion with increasing bladder distension, which was significantly higher during filling with KCl. Based on the excellent correlation between TRCDUS and LDF, TRCDUS seems to be a feasible method in the assessment of urinary bladder neck blood flow. 31886 New bodymarker system for abdominal ultrasonography Taniguchi N,* Kuwata T, Itoh K, Fujii Y, Omoto K, Clinical Laboratory Medicine, Jichi Medical School, Minamikawachi, Japan Objective: Bodymarker is used as a guide for interpreting the ultrasonogram as well as abbreviation of the organ. The aim of this study is to evaluate the superiority of the new bodymarker over that of the conventional bodymarker. Methods: The proposed system uses electromagnetic coordinates to detect the positions and angles of the transducer; the transmitter is
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placed under the bed, and a transducer is attached to the receiver. The new bodymarker produces three-dimensional images, and the transducer position is displayed on it, automatically, by this system. Variation in the physique of the examinees is calibrated using five points to project to the original bodymarker. Results: To estimate its appropriateness, we compared the new bodymarker with transducer position in four abdominal sections. Bodymarker and transducer positions were in close agreement on both position and direction, and the transducer position indicator in the bodymarker display moves smoothly. Conclusions: The proposed three-dimensional bodymarker was accurate and convenient in the clinical setting. 31888 Doppler detection of arterial stenosis: Defining the optimal threshold for a diagnostic test when disease is characterized by a continuous level of severity Halpern EJ,*1 Krieger AM,2 1. Radiology, Thomas Jefferson University, Philadelphia, PA, and 2. Statistics, University of Pennsylvania, Philadelphia, PA Objective: Arterial disease is best characterized by a continuous measure of severity (the % diameter reduction) rather than as a dichotomous condition. Doppler measurements provide a continuous test result related to the severity of stenosis. Given a continuous diagnostic test result, we demonstrate a model to compute the optimal test threshold for the decision to treat or withhold treatment. Methods: Let x denote the severity of disease; g(x) is the distribution of x in the population. Let y denote the test result; f(y兩x) is the distribution of y given x. Assume that g(x) and f(y兩x) are normally distributed, that the expected value of y is linearly related to the severity of disease, and that the utility of treatment is linearly related to the severity of disease. We apply this model to study data derived from a prior article on Doppler detection of renal artery stenosis (Radiology 1995, 195:799 – 804). Results: By extending Baye’s theorem, we demonstrate that for any particular value y of the diagnostic test, x is normally distributed. The distribution of x given y is denoted as h(x兩y) with a mean and variance that may be computed from the means and variances of g(x) and f(y兩x). Empirical analysis of our study data suggests that, for evaluation of renal artery stenosis, g(x) is best approximated by a mixture of normal distributions for healthy and diseased arteries, gh(x) and gd(x), rather than by a single normal distribution. We extend our model to this case to demonstrate that h(x兩y) and hence the expected value of x given y may still be computed from the underlying distributions of g(x) and f(y兩x). A unique optimal test threshold can be computed as long as the variance of gh(x) is less than the variance of gd(x). Our study data clearly conform to this restriction. Conclusions: When disease is characterized by a continuous level of severity, the expected utility of treatment may be derived from a diagnostic test result by computing the expected value of disease severity. For the diagnosis of renal artery stenosis, a unique optimal test threshold can be defined corresponding to the minimum test value that yields a positive expected utility. 31892 Nuchal translucency measurements: A critical evaluation of accuracy Westerway SC,*1,2 Carrigan A,1 1. North Shore Obstetric & Gynaecologic Ultrasound, North Shore Private Hospital, St. Leonards, NSW, Australia, and 2. Obstetrics & Gynaecology, Northern Clinical School, University of Sydney, Sydney, NSW, Australia
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placed under the bed, and a transducer is attached to the receiver. The new bodymarker produces three-dimensional images, and the transducer position is displayed on it, automatically, by this system. Variation in the physique of the examinees is calibrated using five points to project to the original bodymarker. Results: To estimate its appropriateness, we compared the new bodymarker with transducer position in four abdominal sections. Bodymarker and transducer positions were in close agreement on both position and direction, and the transducer position indicator in the bodymarker display moves smoothly. Conclusions: The proposed three-dimensional bodymarker was accurate and convenient in the clinical setting. 31888 Doppler detection of arterial stenosis: Defining the optimal threshold for a diagnostic test when disease is characterized by a continuous level of severity Halpern EJ,*1 Krieger AM,2 1. Radiology, Thomas Jefferson University, Philadelphia, PA, and 2. Statistics, University of Pennsylvania, Philadelphia, PA Objective: Arterial disease is best characterized by a continuous measure of severity (the % diameter reduction) rather than as a dichotomous condition. Doppler measurements provide a continuous test result related to the severity of stenosis. Given a continuous diagnostic test result, we demonstrate a model to compute the optimal test threshold for the decision to treat or withhold treatment. Methods: Let x denote the severity of disease; g(x) is the distribution of x in the population. Let y denote the test result; f(y兩x) is the distribution of y given x. Assume that g(x) and f(y兩x) are normally distributed, that the expected value of y is linearly related to the severity of disease, and that the utility of treatment is linearly related to the severity of disease. We apply this model to study data derived from a prior article on Doppler detection of renal artery stenosis (Radiology 1995, 195:799 – 804). Results: By extending Baye’s theorem, we demonstrate that for any particular value y of the diagnostic test, x is normally distributed. The distribution of x given y is denoted as h(x兩y) with a mean and variance that may be computed from the means and variances of g(x) and f(y兩x). Empirical analysis of our study data suggests that, for evaluation of renal artery stenosis, g(x) is best approximated by a mixture of normal distributions for healthy and diseased arteries, gh(x) and gd(x), rather than by a single normal distribution. We extend our model to this case to demonstrate that h(x兩y) and hence the expected value of x given y may still be computed from the underlying distributions of g(x) and f(y兩x). A unique optimal test threshold can be computed as long as the variance of gh(x) is less than the variance of gd(x). Our study data clearly conform to this restriction. Conclusions: When disease is characterized by a continuous level of severity, the expected utility of treatment may be derived from a diagnostic test result by computing the expected value of disease severity. For the diagnosis of renal artery stenosis, a unique optimal test threshold can be defined corresponding to the minimum test value that yields a positive expected utility. 31892 Nuchal translucency measurements: A critical evaluation of accuracy Westerway SC,*1,2 Carrigan A,1 1. North Shore Obstetric & Gynaecologic Ultrasound, North Shore Private Hospital, St. Leonards, NSW, Australia, and 2. Obstetrics & Gynaecology, Northern Clinical School, University of Sydney, Sydney, NSW, Australia