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Biomedical subjects

M M Abu-Yousef

Publications and source records attributed to M M Abu-Yousef.

At least 19 recordsLinked to original sources
PubMed2001

Ultrasonography of the right lower quadrant.

Whereas acute appendicitis is the most common cause of right lower quadrant (RLQ) pain, numerous other conditions may cause signs and symptoms that mimic acute appendicitis. These include other appendiceal diseases, inflammatory bowel diseases, nonbowel gastrointestinal conditions, urinary diseases, and, in females, gynecologic diseases and conditions associated with pregnancy. The important role of ultrasonography in the diagnosis of not only acute appendicitis but also each of the other conditions that cause RLQ pain is described. The ultrasound criteria for the positive, negative, and indeterminate appendix ultrasound examination and the sensitivity, specificity, and positive and negative predictive values of this modality are discussed. The limitations of ultrasound in such diagnoses are also discussed, and an algorithm for the management of patients with RLQ pain is suggested.

Journal Article↗
PubMed2000

Improved US visualization of the pancreatic tail with simethicone, water, and patient rotation.

PURPOSE: To evaluate the effect of degassed water, simethicone, and patient rotation on ultrasonographic (US) visualization of the pancreatic tail. MATERIALS AND METHODS: Seventy patients in whom visualization of the pancreatic tail was poor at US were reevaluated in the upright position after ingesting 2 cups (500 mL) of water with 80 mg of simethicone followed by rotating three times on the examination table. In a few patients, the right posterior oblique position was used. Pancreatic tail visualization and disbursement of gastric gas were evaluated. Seventy patients who received 500 mL of distilled water only served as control subjects. RESULTS: Pancreatic tail visualization in patients versus control subjects was complete in 55 (79%) versus five (7%) of 70 patients and control subjects, partial in 10 (14%) versus 38 (54%), and not improved in five (7%) versus 27 (39%). The effect on diminishing gastric air was closely correlated with the degree of improved visualization in most patients. All patients tolerated the procedure well, with no side effects. The technique added a mean of 8 versus 5 minutes to the examination in patients versus control subjects. The full acoustic window effect of the simethicone-water mixture lasted approximately 10 minutes. CONCLUSION: The simethicone-water-rotation technique is simple, safe, inexpensive, and effective for improving pancreatic tail visualization in ambulatory patients and is superior to the use of water alone.

Adolescent↗
PubMed1998

Teaching physical examination of the adult liver with use of real-time sonography.

RATIONALE AND OBJECTIVES: The authors developed and evaluated an approach to teaching examination of the liver that incorporates real-time ultrasound (US) imaging as immediate feedback to improve diagnostic accuracy. MATERIALS AND METHODS: Second-year medical students participating in a course in physical examination were assigned to receive instruction in measuring liver span without (group 1) or with (group 2) real-time sonography. Students from each group attended a practice session given by one of two physicians who were board certified in radiology and internal medicine with special expertise in US. During the practice session for group 2, students were shown the boundaries of the liver of the practice patient with real-time US. Both groups of students then made three measurements each of the liver span of a healthy practice patient and a single healthy test patient without US. The vertical liver span reference standard was determined by one of the authors. RESULTS: Students in group 2 showed greater accuracy in measuring liver span during both the practice and the test sessions than did students in group 1. The differences were significant for the third practice measurement and all three test measurements (P < .05). CONCLUSION: The use of real-time US as an aid in teaching physical examination improves students' accuracy in measuring liver size.

Adult↗
PubMed1997

Accuracy of color Doppler sonography in assessing venous thrombus extension in renal cell carcinoma.

OBJECTIVE: Our objective was to evaluate the accuracy of color Doppler sonography for assessing tumor thrombus extension into the renal veins, the inferior vena cava, and the right side of the heart in patients with renal cell carcinoma. MATERIALS AND METHODS: Over the past 4.5 years, 44 patients with 46 renal cell carcinomas were examined with color Doppler sonography for the presence and extent of tumor thrombus in the renal veins, the inferior vena cava, and the right side of the heart. Examinations were performed after an equivocal CT scan in 34 patients and as a primary imaging technique in 10. Color Doppler sonographic findings were correlated with surgical-pathologic findings or findings from autopsies performed within 3 months of the Doppler study. Seven patients were excluded: two because of poor technical quality caused by body habitus and five because pathologic correlation was performed more than 3 months after the color Doppler sonographic examination. The remaining 39 renal vein and 37 caval Doppler examinations constituted the study material. Criteria used for the diagnosis of tumor thrombus included distention of the renal vein or the inferior vena cava by echogenic material and partial or complete absence of flow detected with color Doppler sonographic examination. RESULTS: Sixteen of 39 renal veins evaluated had pathology-proven tumor thrombus. Color Doppler sonography was 87% accurate with a sensitivity of 75%, a specificity of 96%, a positive predictive value of 92%, and a negative predictive value of 85%. In two false-positive cases, involvement was limited to intrarenal veins, causing no change in the surgical approach. Five of 37 inferior venae cavae evaluated had proven involvement by tumor thrombus. Color Doppler sonography was 100% accurate in assessing the presence and extent of inferior vena caval involvement by tumor thrombus. Extension into the right atrium and ventricle that was shown by this technique was proven by surgery in one case. The overall accuracy for detecting venous involvement for both the renal veins and the inferior vena cava was 93%, the sensitivity was 81%, and the specificity was 98%. CONCLUSION: In patients with renal cell carcinoma, color Doppler sonography appears to be fairly accurate in assessing tumor extension into the renal veins, the inferior vena cava, and the right side of the heart. Although CT is the primary imaging technique for staging renal cell carcinoma, color Doppler sonography may be used as a complementary technique for assessing venous extension in patients with an equivocal CT examination.

Carcinoma, Renal Cell↗
PubMed1997

Normal lower limb venous Doppler flow phasicity: is it cardiac or respiratory?

OBJECTIVE: The purposes of this study were to determine the origin and nature of normal lower limb venous Doppler flow phasicity and to assess normal and respiratory variations. SUBJECTS AND METHODS: The common femoral veins of 12 healthy volunteers (three men and nine women; age range, 21-50 years; mean, 29 years) were evaluated by detailed spectral Doppler examinations with simultaneous ECG and respirometric tracings. The examinations were performed using a 5- or 7-MHz linear-array transducer with breath held in mid respiration, at the end of deep expiration, at the end of deep inspiration, during Valsalva's maneuver, and during quiet and deep breathing. The tracing obtained during breath-hold in mid respiration was considered the baseline. Tracings obtained during the other respiratory phases were analyzed for changes from the baseline. Doppler tracings were analyzed for phasicity, waveform frequency, components, velocities, velocity ratios, and presence of retrograde flow, all in correlation with simultaneous ECG and respirometric tracings. Tracings were analyzed independently by two observers to assess interobserver variability. RESULTS: With breath-hold in mid respiration, the common femoral vein Doppler tracings consisted of multiphasic waveforms that had a frequency similar to that of the heart rate. Each waveform consisted of systolic, v, diastolic, and a waves. The systolic wave occurred 0.4 sec later than the QRS complex of the ECG and was always antegrade. The v wave was always retrograde without flow reversal. The diastolic wave was always antegrade. The a wave was always retrograde but showed flow reversal in nine of 12 subjects. The systolic:diastolic velocity ratio ranged from 0.9 to 1.5 (mean, 1.1). The minimum:maximum velocity ratio ranged from -0.4 to 0.2 (mean, -0.15). With breath-hold at the end of expiration, the waveforms became slightly damped, becoming biphasic in five subjects and remaining multiphasic in seven. With breath-hold at the end of inspiration, the waveforms became nonphasic or biphasic in nine and decreased in velocity in 12. With Valsalva's maneuver, flow stopped. With normal respiration, cardiac waveforms were modulated by higher amplitude and less frequent biphasic respiratory waves. The plasticity was equal in two, dominantly cardiac in six, and dominantly respiratory in four. Flow velocity increased with expiration and decreased with inspiration. With deep breathing, the respiratory waves further increased, while the cardiac ones decreased in amplitude. The latter continued to modulate the respiratory phasicity in 10 subjects. CONCLUSION: During quiet respiration, lower limb venous Doppler tracings consisted of both cardiac and respiratory waveforms. Although respiratory waveforms disappeared when patients held their breath, Doppler tracings continued to be multiphasic and cardiac. Therefore, cardiac phasicity in lower limb venous Doppler tracings does not necessarily indicate cardiac disease. Other respiratory phases can modulate this basic cardiac pattern. Decrease in or loss of phasicity in these waveforms does not always mean proximal obstruction, because it can be caused by respiratory factors. Finally, the presence of minimal cyclic retrograde flow that is 5 cm/sec or less does not necessarily indicate cardiac disease.

Adult↗
PubMed1997

Spigelian hernia: diagnosis by high-resolution real-time sonography.

The purpose of this study was to demonstrate the role of high-resolution real-time sonography in the diagnosis of spigelian hernias. The sonographic findings in three patients, two of whom had surgical confirmation, are presented. We also discuss and demonstrate the anatomic and pathologic factors that predispose to these hernias. In all three cases, real-time high-resolution sonography was very helpful in providing detailed images of the abdominal wall defect, the hernial sac and contents, and the relationship of the contents to the spigelian fascia and the rectus, external oblique, and internal oblique muscles. The role of the Valsalva and other provocative maneuvers in demonstrating the "in and out" sliding movement of the contents of the hernia also is discussed. Although the number of cases in our study is small, we think that this modality may be the most effective means for establishing this diagnosis, especially in cases with equivocal clinical findings.

Abdominal Muscles↗
PubMed1996

Pulsatile venous Doppler flow in lower limbs: highly indicative of elevated right atrium pressure.

OBJECTIVE: The purpose of this study was to determine if pulsatile flow in lower limbs as seen on venous Doppler waveforms correlates with increased right atrium pressure. MATERIALS AND METHODS: Of 429 patients who, over a 14-month period, underwent venous Doppler imaging of the lower limb to exclude deep venous thrombosis, 343 records were available for review at the time of the study. Of these, 74 had right atrium pressure measurements available for correlation. Seventeen patients were excluded because of thrombosis in the common femoral vein. Six other patients were also excluded because the time difference between the Doppler and the correlative studies was more than 4 weeks. The remaining 51 patients constituted the study subjects. In 18 of these, the right atrium pressure was measured within 1 week, 31 within 2 weeks, 42 within 3 weeks, and 51 within 4 weeks. In the study, we evaluated the three major veins of the lower limb (the common femoral, superficial femoral, and popliteal) by venous Doppler imaging. Data from only the common femoral vein were included in our analysis because this vessel was the least involved with thrombosis. The findings were correlated with the presence or absence of right-sided heart failure as determined by right atrium pressure measurement. A Doppler waveform was considered pulsatile when it had a cyclic retrograde component. A right atrium pressure of more than 8 mm Hg was considered elevated. RESULTS: Of 51 patients, 17 (33%) had pulsatile lower limb venous Doppler flow waveforms and 33 (65%) had elevated right atrium pressure. We found a statistically significant correlation between the presence of these abnormal waveforms and elevated right atrium pressure. The sensitivity of lower limb venous Doppler imaging for detecting right-sided heart failure as determined by right atrium pressure measurement was 46%, specificity was 94%, positive predictive value was 94%, negative predictive value was 50%, and accuracy was 65%. CONCLUSION: Pulsatile lower limb venous Doppler waveform correlates well with right-sided heart failure, as indicated by a right atrium pressure measurement of more than 8 mm Hg. However, because of its low sensitivity, lower limb venous Doppler imaging cannot be used to screen for right-sided heart failure.

Adult↗
PubMed1996

Pulsatile lower limb venous Doppler flow: prevalence and value in cardiac disease diagnosis.

The purpose of this study was to assess the frequency and significance of pulsatile Doppler waveforms in lower limb veins. We used Doppler sonographic data from the common femoral vein. In the first of two groups, the findings in 250 patients were correlated with the presence of cardiac decompensation on concurrent chest radiographs. In the second group, the findings in 81 patients were correlated with the presence of tricuspid regurgitation on Doppler echocardiograms. A venous Doppler sonographic examination was considered normal if spontaneous anterograde phasic flow was present and pulsatile if flow had a cyclic retrograde component. In group 1, 21% had pulsatile waveforms whereas 24% had cardiac decompensation. In group 2, 36% had pulsatile waveforms and 43% had tricuspid regurgitation. A statistically significant correlation was found between the presence of these abnormal waveforms and cardiac decompensation or tricuspid regurgitation, with sensitivities of 57% and 54%, specificities of 91% and 78%, positive predictive values of 66% and 66%, negative predictive values of 87% and 69%, and accuracies of 82% and 68%, respectively. In a subgroup of 55 patients who had both tests for correlation and in whom both were in agreement, the sensitivity of venous Doppler sonographic examination for detecting pathologic cardiac conditions was 79%, specificity was 87%, positive predictive value was 83%, negative predictive value was 84%, and accuracy was 84%. In 77 patients with pulsatile waveforms, including 24 without concurrent chest radiographs or echocardiograms, 63 (82%) had no prior history of cardiac disease. When correlated separately with chest radiograph or Doppler echocardiography, the test is not very sensitive in the diagnosis of cardiac disease; however, when both correlating tests are performed and are in agreement, all diagnostic parameters of the venous Doppler sonographic test, including sensitivity, become fairly high. The presence of pulsatile lower limb venous Doppler flow should alert the sonologist that a pathologic cardiac condition may be the culprit, especially in patients who have no such prior diagnosis.

Adolescent↗
PubMed1994

Strenuous exercise decreases motility and cross-sectional area of human gastric antrum. A study using ultrasound.

Gastric emptying in humans is delayed with strenuous exercise. We used ultrasound imaging in six healthy volunteers to determine whether changes in motility and configuration of the gastric outlet contribute to this delay. After fasting, all individuals ingested chicken broth and garbanzo beans. With subjects sitting upright, transverse and longitudinal real-time views of the gastric antrum were recorded on video tape. In the exercise studies, subjects pedaled an ergometer for 10 min to attain a heart rate of 85% predicted maximum. On a different day, all subjects had an identical study without exercise. The order of performance of exercise and no-exercise studies was randomized. After exercise, contraction frequencies and antral areas were significantly reduced compared to the studies without exercise. In addition, after exercise there was closure of the pylorus and tubular narrowing of the gastric antrum. Closure of the pylorus and decreased gastric antral area and motility may be important in explaining the decrease in gastric emptying that occurs with strenuous exercise.

Adult↗
PubMed1994

Predictive value of normal endovaginal sonography in excluding disease of the female genital organs and adnexa.

Endovaginal sonograms of all patients that were interpreted normal during 1990 (12 months) were reviewed. Fifty-nine patients with normal EVS (age range, 18 to 63 years; average, 35 years) were followed either clinically for at least 12 months (average, 23 months) (N = 33) or until a definite diagnosis was established by a definitive procedure (N = 26). Of the 33 patients followed clinically, a definite diagnosis was established in nine, whereas in the remaining patients the symptoms resolved without further evaluation. Of the 26 undergoing definitive procedures, a diagnosis was established (six patients) or the procedure revealed normal pelvic organs (20 patients). A missed diagnosis on EVS was defined as failure to see pathologic lesions in the female pelvic genital organs or adnexa. According to our definition, five lesions were missed by EVS. The negative predictive value from a normal EVS was 92%, using patient outcome as the reference standard.

Adnexal Diseases↗
PubMed1993

The configuration of the human gastroduodenal junction in the separate emptying of liquids and solids.

BACKGROUND: The stomach separately empties liquids and large particulate solids. The present study aimed to better define the mechanisms responsible for this separate emptying in humans. METHODS: Real-time ultrasound images of the gastroduodenal junction were tape-recorded in normal volunteers after they ingested a test meal consisting of beans and chicken broth. RESULTS: During early emptying, beans were retained along the gastric greater curve as it bulged caudally. When the pylorus was open, liquids flowed over the beans into the duodenum. Emptying of the occasional bean that appeared in the antrum was blocked by closure of the pylorus. Later, the antrum was tubular in shape with reduced area of cross section, yet the percent narrowing of the lumen with each contraction remained constant. Beans were now in close contact with the contracting antral wall and were transformed into small particles. Only in this state were solids allowed through the pylorus. CONCLUSIONS: Mechanisms by which the human stomach "sieves" liquids from solids include (1) sedimentation of solids in the dependent portion of the stomach, while liquids are "decanted" into the duodenum in early emptying; (2) blockade of large particles from entering the duodenum by closure of the pylorus; and (3) grinding of large particles by the gastric antrum in late emptying.

Adult↗
PubMed1992

Error in radiology: classification and lessons in 182 cases presented at a problem case conference.

The authors review and classify errors in 182 cases that were presented at problem case conferences between August 1986 and October 1990. Errors were classified by means of a system developed 20 years ago and by means of a system developed within the past several years. The authors found that sources of error have changed very little. Errors usually involved failure to consult old radiologic studies or reports, limitations in imaging technique, acquisition of inaccurate or incomplete clinical history, location of a lesion outside the area of interest on an image, lack of knowledge, failure to continue to search for abnormalities after the first abnormality was found, and failure to recognize a normal biologic variant. Errors included 126 perceptual errors (64 false-negative, 15 false-positive, and 47 misclassification errors) and 56 mishaps, including 38 complications and 18 communication errors. In seven cases nonperception errors occurred because established departmental routines were not followed, and in nine cases a new departmental routine was established after a complication occurred. Departmental policy exerts less effect on perception and interpretation errors.

Diagnostic Errors↗
PubMed1992

Normal and respiratory variations of the hepatic and portal venous duplex Doppler waveforms with simultaneous electrocardiographic correlation.

To understand hepatic vein (HV) and portal vein (PV) duplex waveforms and their normal and respiratory variations, HV and PV duplex sonography with simultaneous electrocardiography was performed on 11 volunteers. Absolute velocities of the waveforms' components and their ratios were determined at mid-inspiration, full inspiration, full expiration, and Valsalva maneuver. The normal HV waveform was variable in shape and component velocities and ratios but essentially consisted sequentially of (1) an antegrade systolic wave resulting from movement of the tricuspid annulus toward the cardiac apex and occurring shortly after QRS; (2) a retrograde v-wave resulting from atrial overfilling and occurring immediately after the T-wave; (3) an antegrade diastolic wave resulting from opening of the tricuspid valve and occurring shortly after the T-wave; and (4) a retrograde a-wave resulting from atrial contraction and occurring immediately after the P-wave. The ratio of the maximum systolic velocity to maximum diastolic velocity varied from 1.0 to 2.8 (mean 1.4). Systolic-to-diastolic ratio decreased during inspiration but was always greater than 0.6 and increased during expiration. The Valsalva maneuver diminished waveform pulsatility. PV waveforms were more triphasic than biphasic but less pulsatile, flow was totally antegrade, and respiratory changes were less remarkable than HV waveforms. All normal HV and most normal PV waveforms showed multiphasicity that corresponded to cyclic cardiac changes. The shapes of these waveforms were variable and were modified by respiratory movements.

Adult↗
PubMed1991

Duplex Doppler sonography of the hepatic vein in tricuspid regurgitation.

Patients with tricuspid regurgitation may present initially with vague abdominal symptoms and elevated liver enzymes. In the absence of diagnostic sonographic findings, patients may be subjected to an unnecessary invasive liver biopsy for an accurate diagnosis. We recently described the association of the pulsatile portal venous waveform on duplex Doppler sonography with tricuspid regurgitation in 15 patients. In this study I describe the changes in the hepatic venous waveform in these patients and compare the findings with the final diagnosis as determined by Doppler echocardiography (n = 14) or ultrafast CT (n = 1). All patients had clinical findings consistent with liver dysfunction and were referred for sonography to rule out diseases of the liver, biliary tree, or hepatic or portal veins. All patients had persistently dilated hepatic veins and inferior venae cavae. Twenty-four volunteers, 11 of whom had simultaneous ECG tracings, served as a control group. The main findings on the hepatic duplex sonogram in the disease group were a decrease in the size of the antegrade systolic wave with a systolic/diastolic flow velocity ratio of less than 0.6 (n = 4) or reversal of the systolic wave (n = 10). In all volunteers, systolic flow was antegrade and the ratio was more than 0.6. Two diagnoses were false positive and one was false negative. In some patients with sonographic signs of congestive heart failure, duplex Doppler sonography of the hepatic vein may be helpful in the diagnosis of one of the causes of liver dysfunction, tricuspid regurgitation.

Adolescent↗
PubMed1990

Solitary intrahepatic biliary cyst: diagnostic and therapeutic strategy.

This paper describes a newborn infant in whom an intrahepatic biliary cyst was successfully demonstrated by antenatal ultrasound. Postnatally, percutaneous cyst aspiration and computed tomography enhanced with intravenous cholangiographic contrast proved extremely helpful in the selection of surgical procedure. The lesion was completely removed at 12 weeks of age without complications.

Bile Duct Diseases↗