Variabilities in measurement of coronary arterial dimensions resulting from variations in cineframe selection

To quantitatively analyze a coronary arterial segment from a cineangiogram, an end-diastolic or neighboring cineframe is usually selected, such that a possibly existing coronary lesion is visualized optimally, as judged by the cardiologist. However, different cardiologists may select different (although usually neighboring) frames, even when following the same selection criteria. It is also possible that the frames are selected from different cardiac cycles. In this study the effects of such phase shifts on the reproducibility of the quantitative measurements were studied. In a total of 38 consecutive patient films obtained at a filmspeed of 25 frames/sec, the frame 0 demonstrating the severity of a lesion optimally, as judged by a senior cardiologist, the three preceding frames, the three following frames and one frame exactly one cycle prior to or following frame 0 were selected; frame 0 was always chosen in the end-diastolic phase of the cardiac cycle. In each film one coronary arterial segment with a focal lesion was analyzed quantitatively in these eight frames with the Cardiovascular Angiography Analysis System (CAAS). No significant differences were found in the mean difference and the standard deviations of the differences (variabilities) in the obstruction diameter, interpolated reference diameter, percent diameter stenosis, extent of the obstruction and area of atherosclerotic plaque obtained in the various frames with respect to frame 0. Therefore, it may be concluded that the selection of a cineframe for quantitative analysis in the end-diastolic phase of the cardiac cycle is not very critical; in other words, the obstruction measurements are not time-dependent for frames in the end-diastolic phase.(ABSTRACT TRUNCATED AT 250 WORDS)     

Risk factors for amputation in patients with diabetes mellitus. A case-control study.

OBJECTIVE: To identify and quantify risk factors for lower extremity amputation in persons with diabetes mellitus. DESIGN: Case-control study. SETTING: A Veterans Affairs medical center. PATIENTS: Eighty patients having amputation associated with diabetes and 236 diabetic controls without limb lesions were enrolled before surgery from the 21,167 inpatient care and outpatient surgical patients seen at the Seattle Veterans Affairs Medical Center during a 30-month period. MEASUREMENTS: Selected vascular, neuropathic, environmental, health care, self care, nutritional, metabolic, lifestyle, and psychosocial risk factors were measured in all patients before surgery. RESULTS: Statistically significant risk factors identified from analysis included insufficient mean below-knee and foot cutaneous circulation (odds ratio, 161; 95% CI, 55.1 to 469); ankle-arm blood pressure index less than 0.45 (odds ratio, 55.8; CI, 14.9 to 209); absence of lower leg vibratory perception (odds ratio, 15.5; CI, 8.3 to 28.7); low levels of high-density lipoprotein (HDL) subfraction 3 less than or equal to 0.7 mumol/L (odds ratio, 4.9; CI, 2.9 to 8.3); and no previous outpatient diabetes education (odds ratio, 3.2; CI, 1.6 to 6.6). A logistic regression analysis done to control for the potentially confounding effects of age; race; socioeconomic status; diabetes duration, type, and severity confirmed these findings and added a statistically significant interaction between foot transcutaneous oxygen tension and peripheral vascular disease history. Clinical interventions to alter these risk factors were identified, including aggressive treatment of infection, diabetes education, protective footwear, and preventive footcare. CONCLUSIONS: Multiple risk factors exist along the continuum of conditions and events leading to lower extremity amputation in diabetes. Modification of certain risk factors by patients and health professionals may reduce the risk for amputation and thus decrease the human and dollar costs that accompany limb loss in this prevalent chronic disease.     

Quantitative analysis in single photon emission tomography (SPET).

Quantitative analysis can improve the sensitivity and specificity of single photon emission tomography (SPET) procedures, as well as reduce inter- and intraobserver variabilities. Quantification of the radioactivity distribution is the ultimate goal of SPET. In this review we consider the basic requirements for an optimum three-dimensional reconstruction of the radionuclide distribution to enable quantification. Attenuation and scatter correction as well as varying resolution are the major problems. In the older SPET systems quantification was hampered by the lack of system sensitivity and sufficient computer power. Therefore, the imaging system was often assumed to be shift invariant and linear and the attenuation throughout the object uniform. More sophisticated solutions have been proposed and with more or less success implemented, but not for application in daily practice. Knowledge (measurement) of the attenuation is often required. New generation SPET systems employing multi-detectors and super minicomputers will ease the implementation of these solutions.     

Transmastoid labyrinthectomy in older patients

Transmastoid labyrinthectomy is an effective procedure for the control of episodic vertigo due to unilateral peripheral vestibular dysfunction. However, its application in older patients has been limited, primarily because of concerns that older patients may not compensate well postoperatively. Poor vestibular compensation results in constant disequilibrium, motion intolerance, and visual symptomatology. The purpose of this report is to review our results with transmastoid labyrinthectomy in patients over the age of 65. Complete records were available for 22 patients operated on between July 1984 and June 1994. Patient's records were reviewed for age, preoperative duration of symptoms, coexistent medical conditions, vertigo control, and postoperative disequilibrium. Advanced age need not be a contraindication to transmastoid labyrinthectomy. Laryngoscope, 105:1152-1154, 1995     

An urban epidemic of North American blastomycosis.

Five culturally proved cases of blastomycosis occurred in a 9-month period during 1974 and 1975 in a western suburb of Chicago. All patients lived within a 1-mile radius of the center of Westmont, Ill. (population, 12,000). Three of these patients lived in adjacent buildings in the same apartment complex. None of the patients had significant outdoor exposure. Dust from a nearby construction site was postulated as a possible common source, although soil cultures from the area were negative. This is the third chronologic epidemic of the blastomycosis; a fourth one has been reported. It is the only outbreak to occur in a major metropolitan area.