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Biomedical subjects

M Quan

Publications and source records attributed to M Quan.

At least 19 recordsLinked to original sources
PubMed1992

Can signal intensity of the continuous wave Doppler regurgitant jet estimate severity of mitral regurgitation?

Visual estimates of the intensity of the continuous wave (CW) Doppler regurgitant jet signal have been used to estimate the severity of valvular regurgitation. Theoretically, the strength of the reflected Doppler signal is a function of the number of scatterers. To test this approach quantitatively, free jets were produced in 27 experiments using a power injector and cornstarch suspension varying in concentration from 1% to 3%. Flow volume was varied from 5 to 15 ml, and orifice diameter varied from 2.5 to 10 mm. Machine settings were kept constant. Also, 22 patients with mitral regurgitation (MR)--5 mild, 11 moderate, and 6 severe by angiography--were studied. Average signal intensity under the CW Doppler flow curve was calculated using a computer image processor. In MR patients, average regurgitant flow (RF) intensity was compared with average mitral forward flow (FF) signal intensity. (1) The intensity under the CW flow signal in the free jet experiments correlated well with injection volume (r greater than 0.98). (2) RF average signal intensity did not correlate with angiographic MR severity (r = 0.21), but the ratio of RF to FF average signal intensity did correlate with MR severity (r = 0.73). (3) The sensitivity and the specificity of an RF/FF ratio greater than 0.65 for angiographically severe mitral regurgitation were both 83%. (4) The sensitivity and specificity of an RF/FF ratio less than 0.50 for angiographic mild mitral regurgitation were both 80%. The ratio of regurgitant to forward mitral flow CW Doppler signal intensity appears to be an accurate and clinically applicable method for estimating the severity of mitral regurgitation.

Adult↗
PubMed1992

Diagnosis of acute pelvic pain.

The diagnosis of acute pelvic pain in the woman of reproductive age represents a major clinical challenge. In approaching such a patient, the clinician must differentiate between pregnancy-related causes, gynecologic disorders, and nonreproductive tract causes. A careful history and physical examination, along with selective and knowledgeable use of diagnostic tests and procedures, are essential to the diagnostic process. Diagnostic laparoscopy represents the reference standard for diagnosis of many of its possible causes and can obviate the need for exploratory laparotomy. Once competing diagnoses have been adequately excluded, an empiric trial of antibiotic therapy for acute pelvic inflammatory disease, coupled with close clinical follow-up, should be considered in patients with acute pelvic pain found to have cervical motion tenderness and bilateral adnexal tenderness on examination.

Acute Disease↗
PubMed1991

Doppler color flow "proximal isovelocity surface area" method for estimating volume flow rate: effects of orifice shape and machine factors.

Previously described Doppler color flow mapping methods for estimating the severity of valvular regurgitation have focused on the distal jet. In this study, a newer Doppler color flow technique, focusing on the flow proximal to an orifice, was used. This method identifies a proximal isovelocity surface area (PISA) by displaying an aliasing interface. Volume flow rate (cm3/s) can be calculated as PISA (cm2) x aliasing velocity (cm/s). For planar circular orifices, a hemi-elliptic model accurately approximated the shape of PISA. Clinically, however, orifice shapes may be noncircular. In vitro flow experiments (n = 226) using orifices of various shapes (ellipse, square, triangle, star, rectangle) were performed. Volume flow rate calculated using a hemi-elliptic model for PISA was accurate, with average percent differences from actual flow rate = +4.3% for a square, -4.2% for a triangle, -4.7% for a star, -4.5% for an ellipse and -2.8% for a rectangle. However, average percent differences for calculated volume flow rates using a hemispheric model for PISA shape ranged from -11.6% (square) to -34.8% (rectangle). In addition, to evaluate whether PISA is influenced by machine factors, in vitro studies (n = 83) were performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Flow Velocity↗
PubMed1987

Chronic pelvic pain.

Chronic pelvic pain is one of the most challenging gynecologic problems seen in primary care practice. Important causes of this problem include endometriosis, pelvic adhesions, chronic pelvic inflammatory disease, and the syndrome of chronic pelvic pain without obvious pathology. The diagnostic approach to chronic pelvic pain begins with a careful medical history and physical examination in conjunction with a comprehensive psychosocial assessment. Laboratory evaluation may include pelvic ultrasonography, psychometric testing, and diagnostic laparoscopy. Optimal management of these patients may require a multidisciplinary approach, integrating chronic pain management techniques with specific therapy.

Female↗
PubMed1985

Physician compliance with colorectal cancer screening (1978-1983): the impact of flexible sigmoidoscopy.

Physician compliance with widely recommended colorectal cancer screening methods was studied over a five-year period in a university-based family medicine residency program. Indicated examinations were being avoided in symptomatic as well as asymptomatic patients aged over 50 years. The introduction of flexible sigmoidoscopy created significant change in previously documented poor resident and faculty compliance. Baseline measurement of outcomes was noted by audit of 189 adult medical records (year 1). Educational reemphasis by lecture and intragroup commitment produced no change by the end of year 2 (n = 189). Introduction of the flexible sigmoidoscope yielded a sevenfold increase in physician compliance in year 3 (n = 192). This compliance increased as measured by chart audit in years 4 (n = 166) and 5 (n = 190). All audited groups were mutually exclusive. The documented diagnostic superiority of this instrument was readily obtainable by family physician faculty and residents in training. With Papanicolaou smear activity serving as a control group, the findings indicated a significant and sustained effect. Two additional primary care training programs were audited during the final year of the study period. These control audits revealed continued poor compliance with rigid sigmoidoscopy. The flexible sigmoidoscope is an important addition to the diagnostic and screening armamentarium of a family medicine residency program.

Adult↗
PubMed1984

Barium enema after flexible sigmoidoscopy: is delay necessary?

There exists a traditional belief that sigmoidoscopy immediately prior to barium enema produces excessive gas and irritability, which subsequently interfere with performance and interpretation of the barium enema study. A survey was initiated to determine whether primary care physicians are generally advised not to perform barium enema examination immediately following proctosigmoidoscopy on the same day. Almost two thirds (56/89) of the physicians indicated that delaying barium enema examination was standard practice in their community. A prospective study was performed on 16 subjects who were examined by a 60-cm flexible sigmoidoscope and then sent for air-contrast barium enema. Ninety-four percent (15/16) of the subjects completed radiologic examinations with no increase in technical difficulty or patient discomfort. One subject was considered to have excessive gas on scout film and was rescheduled for barium enema examination on another day. This preliminary study supports the hypothesis that the majority of patients can sequentially receive both examinations on the same day. For appropriate patients this scheduling would represent a great savings in time, effort, and exposure to bowel preparation protocols.

Attitude of Health Personnel↗
PubMed1984

Continued assessment of flexible sigmoidoscopy in a family practice residency.

The UCLA Family Practice Residency continues to use 60-cm flexible sigmoidoscopy in the care of patients. Between July 1980 and June 1983, 450 patients received an examination with the 60-cm flexible sigmoidoscope. One or more adenomatous polyps were detected in 21 patients. Adenocarcinoma was found in five patients. Four patients were found to have a villous adenoma, and four patients were determined to have inflammatory bowel disease. Of the 34 discrete lesions, 32 percent, 41 percent, and 27 percent were located between 0 and 20 cm, 21 and 35 cm, and 36 and 60 cm, respectively, from the anus. No complications were encountered. Sixty-four percent of the examinations were done by a family practice resident supervised by a full-time faculty member. The remaining 36 percent of the examinations were performed by full-time faculty. The overall detection rate for significant pathology was 8.0 percent. Most pathology by far was found in symptomatic patients. These results validate the safety and viability of 60-cm flexible sigmoidoscopy when performed by properly trained family physicians and family practice residents-in-training.

Adenocarcinoma↗
PubMed1983

Pelvic inflammatory disease.

The rising incidence of pelvic inflammatory disease (PID), coupled with the development of more sophisticated and effective diagnostic techniques, has created a new body of knowledge regarding the microbiology, diagnosis, and natural history of this disease. Acute pelvic inflammatory disease is the major gynecologic health problem in the United States. Distinguishing acute PID from the other causes of acute pelvic pain is often a difficult task. Careful consideration of a patient's risk profile for PID and utilization of the diagnostic techniques available are invaluable in helping the clinician accurately make this differentiation. The microbial spectrum involved in PID is complex and must be taken into consideration when selecting an antibiotic regimen. The recent addition of new, broad-spectrum antibiotics to the physician's therapeutic armamentarium has led to increasingly effective management options. Despite the effectiveness of current medical and surgical therapy, the staggering economic, medical, and social consequences of PID mandates more aggressive efforts at its prevention.

Adolescent↗
PubMed1983

Transient ischemic attacks.

Patients with transient cerebral ischemic attacks (TIAs) are generally felt to be at increased risk for stroke. A comprehensive clinical evaluation consisting of a thorough history and physical examination, as well as adjunctive laboratory and radiologic studies, is required to substantiate the diagnosis and to identify the underlying etiology. For patients with TIAs of atherothrombotic origin, the optimal course of management is still controversial. Although surgical therapy, antiplatelet therapy, and anticoagulant therapy have all shown promise in preventing stroke, their precise roles in the management of TIAs still await further elucidation.

Aged↗
PubMed1983

Adult immunization: the medical record design as a facilitator for physician compliance.

A three-year prospective chart audit of a family practice residency program was performed to measure physician compliance in following the recommendations of an adult immunization program. Despite curriculum changes, performance self-evaluation, and reminders by faculty members to residents about the need for adult immunization, physician compliance was poor in the second year of the study. It was thought that components of the medical record might be improved to facilitate physician compliance in the adult immunization program. At the beginning of the third year of the audit, tetanus and pneumococcal vaccines were preprinted on the health maintenance inventory (HMI), but influenza was not. The chart design also was changed to put the HMI in a more prominent place. In the third year of the audit, physician compliance with tetanus and pneumococcus immunization improved significantly. The results of the chart review suggest that physician compliance with adult immunization programs can be improved with appropriate chart design.

Adult↗
PubMed1982

Ectopic pregnancy.

Ectopic pregnancy continues to be a major clinical problem and is the leading cause of death in the first trimester of pregnancy. Diagnosis can be elusive. A thorough knowledge of the clinical spectrum of this disease, as well as the diagnostic tools available to the primary care clinician, provides the opportunity for making an early diagnosis. This is essential if the morbidity and mortality of ectopic pregnancy are to be reduced.

Adult↗
PubMed1982

Asymptomatic carotid bruit.

The asymptomatic carotid bruit is not an uncommon finding in patients aged 45 years and older. The presence of such a finding has been associated with an increased incidence of stroke and cardiovascular death. The optimal evaluation and management of such patients are still unresolved. Noninvasive carotid evaluation appears to be useful for defining the degree of carotid artery stenosis and possibly in identifying a particular subset of patients at high risk for stroke. Whether patients with asymptomatic carotid bruits are best managed medically or surgically remains controversial and will require further investigation.

Carotid Artery Diseases↗
PubMed1982

Flexible sigmoidoscopy.

Flexible sigmoidoscopy became available in 1976. To date, studies comparing it with rigid sigmoidoscopy support an increase of 2.5 to six times in the flexible sigmoidoscope's ability to detect polyps, and a two- to threefold increase in detection of colonic neoplasms in the same patients. This paper summarizes the current reported results of flexible sigmoidoscopy to date and describes the instrument and procedure as done at the UCLA Family Practice Residency Program. The flexible sigmoidoscope deserves evaluation for widespread primary care application.

Colonic Neoplasms↗