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Biomedical subjects

W D Foley

Publications and source records attributed to W D Foley.

At least 37 records · Page 2Linked to original sources
PubMed1991

Color Doppler flow imaging.

The performance requirements and operational parameters of a color Doppler system are outlined. The ability of an operator to recognize normal and abnormal variations in physiologic flow and artifacts caused by noise and aliasing is emphasized. The use of color Doppler flow imaging is described for the vessels of the neck and extremities, upper abdomen and abdominal transplants, obstetrics and gynecology, dialysis fistulas, and testicular and penile flow imaging.

Abdomen↗
PubMed1991

Color Doppler sonography in the evaluation of erectile dysfunction: patterns of temporal response to papaverine.

Most studies of duplex Doppler sonography for the assessment of erectile dysfunction involve determination of peak systolic velocities 5 min after intracavernosal injection of papaverine. The purpose of this study was to determine the effect of the timing of Doppler measurements of flow after papaverine injection for establishing the presence of arterial and venous abnormalities. Color Doppler sonography was performed in 75 patients for evaluation of vasculogenic impotence. After intracavernosal injection of 60 mg of papaverine, measurements of peak systolic and end-diastolic velocities were obtained in each cavernosal artery at 5-min intervals for a total of 30 min. A peak systolic velocity of less than 25 cm/sec was used as the threshold for arterial insufficiency. An end-diastolic velocity of greater than 5 cm/sec was used to predict venous incompetence. Scanning was performed for direct assessment of dorsal venous flow. Thirty patients were subsequently evaluated by cavernosometry and cavernosography. In most patients (76%), maximum response to papaverine was achieved within the first 5 min. In eight patients, significant increases in systolic velocity were seen only after 5 min. In 10 patients, significant changes in end-diastolic velocity between 5 and 30 min resulted in diagnostic reclassification. Data acquisition for 30 min significantly improved the sensitivity (95%) and specificity (83%) for the prediction of venous incompetence in patients with correlative cavernosography. Transient, early dorsal vein flow was noted in normal subjects. Persistent dorsal vein flow had an 80% sensitivity and 100% specificity for venous incompetence. Our results suggest that, when using color Doppler sonography, gathering data for 30 min may improve the prediction of vasculogenic impotence.

Adult↗
PubMed1991

Evaluation of renal transplant dysfunction using color Doppler sonography.

Color Doppler sonography (CDS) detects changes in renal blood flow that may be useful in evaluating renal transplant dysfunction (RTD). To assess the performance of CDS as a clinical test, we reviewed results from 223 CDS measurements in 130 renal transplant recipients during a 26 month period. Spectral wave forms were characterized by pulsatility index (PI) (maximum frequency shift minus minimum frequency shift divided by mean frequency shift). In 27 individuals with stable renal function, mean PI was 1.80 +/- 0.23 (S.D.). Abnormal PI were subsequently defined as greater than two S.D. more than the mean (PI greater than or equal to 2.3). CDS performed during the early post-transplant period (n = 91) could not differentiate acute tubular necrosis (ATN), obstruction and rejection. Abnormal studies were seen in 35 of 46 instances of ATN and in three of obstruction. In 132 studies done after the postoperative period, CDS became abnormal during rejection episodes in only 45 of 71 instances (sensitivity rate of 63 per cent). When abnormal, CDS was highly suggestive of rejection, however (45 of 49, 92 per cent specificity). Cyclosporine toxicity was not associated with abnormal pulsatility (zero of seven). In 68 instances, CDS and conventional 99mTc DTPA renogram flow studies were performed together within 24 hours. CDS was more sensitive in detecting rejection but the difference did not reach statistical significance (25 of 36 versus 17 of 36). The major advantage of CDS over conventional radionuclide imaging relates to its shorter examination time, lower cost and portable capabilities. CDS will probably become the roentgenologic imaging modality of choice in renal transplantation.

Color↗
PubMed1991

Computed tomography. Focal and diffuse liver disease.

Contrast enhanced CT is very accurate in the detection of focal hepatic disease. Lesion characterization is a more complex issue, in some instances requiring a combination of CT and other diagnostic tests or biopsy for accurate diagnosis. Although CT remains the modality of choice in the evaluation of suspected focal hepatic disease, this role may change if progress in MR imaging leads to further improvements in lesion detection and characterization.

Contrast Media↗
PubMed1990

Display of CT studies on a two-screen electronic workstation versus a film panel alternator: sensitivity and efficiency among radiologists.

Prototype electronic workstations incorporated in networks linking computed tomographic (CT) and magnetic resonance imaging systems are being developed. The authors compared observer efficiency and sensitivity in reading body CT studies from a two-screen workstation (1,000-line monitors and 12-bit dynamic range in image memory) and conventional film panel alternator. The two-screen workstation displayed 32 images at a matrix resolution of 256 x 256 or eight images at a matrix resolution of 512 x 512 simultaneously. Ninety-six images with a matrix resolution of 512 x 512 could be displayed simultaneously at the film panel alternator. Four observers read images from 20 cases, 10 with repeat examinations, in a randomized viewing sequence. There was an average of 32 images per case. Reporting time was less with the film panel alternator (average, 5.08 minutes) than with the workstation (average, 6.66 minutes). There was improved sensitivity for all observers in reading from the film panel alternator (range, 1%-12%) (P less than .05). In complex cases evaluated by means of body CT, the current prototype two-screen electronic workstation is limited by display capabilities.

Data Display↗
PubMed1990

Color Doppler sonographic imaging in the assessment of upper-extremity deep venous thrombosis.

Color Doppler flow imaging with linear-array transducers was performed in 130 extremities in 91 patients with suspected upper-extremity deep venous thrombosis. Thrombi were detected in 39 studies (30%). Eighty-four patients had either imaging examinations (22 studies comprising venography in 20 patients, CT in one, and MR imaging in one) or clinical follow-up (99 studies) for correlation. In studies with imaging correlation, the sensitivity of the Doppler studies was 78% and the specificity was 92%. There were two false-negative examinations in which the proximal subclavian vein either could not be imaged or the anatomy was distorted. There was one false-positive color Doppler diagnosis of deep venous thrombosis in a case of partial obstruction of the subclavian vein caused by extrinsic compression. There were no known additional errors in color Doppler imaging in patients who had clinical follow-up. Four cases of isolated superior vena cava or proximal innominate vein obstruction were missed by color Doppler imaging. Color Doppler flow imaging is an accurate, noninvasive method for the evaluation of upper-extremity deep venous thrombosis. Other imaging tests may be required when the color Doppler study is negative and central venous thrombosis is suspected.

Adolescent↗
PubMed1989

Color Doppler evaluation of arterial stenoses and occlusions involving the neck and thoracic inlet.

Color Doppler flow imaging is a new technique providing simultaneous display of a gray-scale tissue and a color-flow vascular image. We demonstrate its ability to predict accurately occlusions of numerous vessels, including the internal carotid, external carotid, common carotid, subclavian and innominate arteries. Alterations in flow direction and changes in spectral wave form provide useful clues to the presence of these occlusions. The cases are correlated with angiographic findings and functional flow diagrams of the hemodynamic changes involved.

Arterial Occlusive Diseases↗
PubMed1989

Dynamic hepatic CT.

A technique for incremental dynamic computed tomography (CT) of the liver with boluses of contrast material (with a 50-g iodine load) administered intravenously is described. For most focal liver lesions, which are hypovascular in relation to normal hepatic parenchyma, bolus contrast material enhancement and incremental dynamic scanning improve detectability, compared with that yielded by nondynamic, contrast material infusion techniques. The bolus contrast-enhanced dynamic scan technique is reproducible and of value in patients undergoing sequential CT for assessment of tumor bulk response to chemotherapy. Patients who are potential candidates for resection of focal hepatic lesions should preoperatively undergo intraarterial contrast-enhanced CT. Intravenous bolus enhanced dynamic hepatic CT can be extended to cover more than one anatomic region (eg, abdomen and thorax), as in patients undergoing CT for staging lung carcinoma. In these patients, incremental scan sequences are programmed caudad to cephalad. Incremental dynamic CT is also an appropriate technique to use in cooperative patients who have suffered blunt abdominal trauma.

Contrast Media↗
PubMed1989

Thrombosis at venous insertion sites after inferior vena caval filter placement.

Color Doppler flow imaging or compression ultrasound (US) was used to prospectively determine frequency of thrombosis at 54 venous insertion sites (47 in common femoral veins, seven in right internal jugular veins) after percutaneous placement of Greenfield filters for interruption of the inferior vena cava. Fifty-one filters were successfully placed in 51 patients with a dilator set or a balloon angioplasty catheter. Nine focal thrombi were detected in the common femoral vein (19%) and one in the right internal jugular vein (14%). Use of dilators induced eight thrombi (24%), compared with two (10%) from balloon catheters. The left common femoral vein had a high frequency of thrombosis, regardless of dilation technique (five of nine). Of nine patients with acute common femoral vein thrombosis, four became symptomatic within 10 days after the procedure. Patients may remain asymptomatic or have delayed symptoms; thus, US is valuable for determining patients at risk of thrombosis of the common femoral vein.

Catheterization↗
PubMed1989

Color Doppler flow imaging of the normal and abnormal orbit.

Twenty-six normal orbits (16 subjects) and seven patients with suspected orbital disease were studied with color Doppler flow imaging CDFI). Arterial structures consistently identified included the ophthalmic artery, central retinal artery, and posterior ciliary branches. The terminal lacrimal branch was seen in the majority of orbits (n = 19). Venous structures consistently seen included the central retinal vein and venae vorticosae; the superior ophthalmic vein was identified in the majority of normal orbits (n = 22). Response of the superior ophthalmic vein to the Valsalva maneuver was assessed in six of the normal subjects (12 orbits). Retrograde flow was typically seen during the maneuver and accentuated antegrade flow after cessation of the maneuver. Pathologic entities correctly diagnosed with CDFI included a dural arteriovenous malformation (AVM) with spontaneous carotid-cavernous fistula, an orbital AVM, and superior ophthalmic vein thrombosis. Vascular lesions were excluded in two patients with orbital masses. Bilaterally enlarged superior ophthalmic veins were identified in a patient with unilateral symptoms suggestive of a varix; CDFI results were confirmed with computed tomography, but orbital venograms were interpreted as normal. These findings suggest that CDFI may be helpful in the evaluation of suspected vascular orbital disease.

Adult↗
PubMed1989

Color Doppler ultrasound imaging of lower-extremity venous disease.

A color Doppler ultrasound imaging device was used to evaluate 475 patients with suspected lower-extremity venous thrombosis. Occlusive and nonocclusive femoral and popliteal thrombi were detected in 200 studies (42%). In phase 1 of the study (240 examinations), peripheral augmentation with the use of periodic calf compression was required to show color flow throughout the femoropopliteal venous segment. In phase 2 (235 examinations), with a software upgrade to enhance detectability of slow flow, spontaneous flow could be appreciated in the normal, partly thrombosed, and recanalized femoral popliteal veins without augmentation. Augmentation was often necessary to view tibioperoneal veins. Of the total study group, conventional venography was performed for correlation in 47 patients. In the other patients, clinicians relied on the color Doppler test for the definitive diagnosis of the presence or absence of femoral popliteal venous thrombosis and treated these patients on the basis of the color Doppler test result. In the femoral veins, color Doppler studies and venography agreed in all 12 positive and 35 negative cases. In the popliteal veins, there was agreement in five isolated popliteal thromboses and in 10 femoral popliteal thromboses; there were two false-negative color Doppler studies of isolated popliteal thromboses. In four patients, Doppler studies detected nonocclusive thrombus not evident on venography. Color Doppler imaging is easy to perform and does not require augmentation to view color flow in the femoropopliteal venous segment. Eccentric thrombus and partially canalized thrombus can be shown. Initial experience suggests color Doppler imaging may be useful in the detection of tibioperoneal venous thrombosis.

Femoral Vein↗
PubMed1989

Stenosis of the internal carotid artery: assessment using color Doppler imaging compared with angiography.

The percentage of diameter stenosis of the internal carotid artery was estimated directly from color Doppler images obtained in both longitudinal and transverse planes and compared with the results of digital subtraction angiography in 49 patients (95 carotid arteries). Peak systolic velocity measurements were obtained by placing the sample volume in the highest-velocity flow stream with the angle-correction cursor parallel to the color-encoded lumen. Arterial stenoses were categorized on a grade 1-5 scale: 1 = 0-15%, 2 = 16-49%, 3 = 50-75%, 4 = 76-99%, and 5 = occlusion. Percent diameter stenosis could not be determined in 12 color Doppler flow imaging studies (13%) due to calcified plaque. Of the remaining 83 arteries evaluated by both techniques, the respective categories by color Doppler flow imaging/angiography were grade 1 (16/26), grade 2 (25/24), grade 3 (30/19), grade 4 (5/8), and grade 5 (7/6). Percent diameter stenosis determined by color Doppler flow imaging was greater than by angiography in 25% and less than by angiography in 4%. Peak systolic velocity measurements did not separate the hemodynamically insignificant (less than 50% diameter stenosis) grade 1 and grade 2 lesions, but were in agreement in 86% of grades 3-5 stenotic categories, as determined by measurements from the color Doppler flow image. A direct measurement of percent diameter stenosis from the color Doppler flow image was possible in 87% of cases. Peak systolic velocity provided correlative diagnostic information when assessing hemodynamically significant lesions.

Angiography↗
PubMed1989

Renal imaging in long-term dialysis patients: a comparison of CT and sonography.

Patients undergoing long-term dialysis are subject to cyst formation, hemorrhage, and neoplasia in their native kidneys. Detection of these complications with incremental dynamic CT and detection with sonography were compared prospectively in 41 patients (79 kidneys) who had been undergoing dialysis intermittently for 3 or more years. Acquired cystic kidney disease (five or more cysts per kidney) was identified in 59% of kidneys by use of CT and in 18% by use of sonography. CT showed a complete renal contour definition in all cases, sonography did so in only 57%. Three solid renal tumors (2- to 4-cm diameter) were identified with both techniques with no false-negative evaluations. Four benign hemorrhagic cysts were identified with combined CT (hyperdense mass) and sonography (benign cysts). CT provided the best anatomic image quality and was more accurate for detection of acquired cystic kidney disease. CT and sonography were equivalent for detection of solid tumors. Our results suggest that dynamic contrast-enhanced CT scanning with the supplemental use of sonography is the best imaging regimen for the evaluation of suspected acquired cystic kidney disease and its potential complications.

Adolescent↗
PubMed1988

Flow reversal in the normal carotid bifurcation: color Doppler flow imaging analysis.

One hundred carotid bifurcations in young asymptomatic volunteers were examined with color Doppler flow imaging in an attempt to determine the frequency, configuration, magnitude, and duration of flow reversal. Areas of flow reversal were identified in all but one bifurcation. Just proximal to the bifurcation, flow reversal was typically located peripherally, opposite the origin of the external carotid artery. Distal to the bifurcation, flow reversal in the internal carotid artery typically assumed a linear configuration in the center of the vessel, extending from the superficial to the deep wall. Variations of these patterns were common. On the average, flow reversal occupied 33% of the lumen of the carotid bulb and extended for a distance of 14 mm. The average duration of flow reversal was 22% of the total cardiac cycle, with reversal typically occurring at peak systole and being replaced by static blood during diastole. These findings indicate that flow reversal in the carotid bifurcation is a normal phenomenon with a variable configuration, magnitude, and duration.

Adult↗
PubMed1988

Renal calculi: sensitivity for detection with US.

The sensitivity of sonography in the detection of renal calculi was tested in a three-phase study in 100 patients. In phase 1, ultrasonographic (US) scanning was performed after review of abdominal radiographs and renal tomograms in 30 patients who had undergone extracorporeal shock wave lithotripsy (ESWL). In this group the sensitivity of US for detecting stones was 98%. In phase 2, scanning was performed in 30 post-ESWL patients without prior review of radiographs or tomograms. The sensitivity of US for stone detection in this group was 95%. In phase 3, sonography was performed in a blinded fashion on a random mix of post-ESWL patients and patients who had undergone urography for reasons unrelated to nephrolithiasis. The sensitivity of US for stone detection in this group of 40 patients was 91%. The overall sensitivity in all three groups was 96%, which was superior to the performance of abdominal radiography and slightly inferior to the combination of abdominal radiography and renal tomography. The ability to detect kidney stones with US depended on stone size but was independent of stone location or patient size. The study findings suggest that US is an effective means for detecting kidney stones in patients with suspected nephrolithiasis.

Humans↗