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Biomedical subjects

W D Foley

Publications and source records attributed to W D Foley.

At least 91 records · Page 5Linked to original sources
PubMed1985

Intra-arterial digital subtraction angiography.

DSA is an imaging technique that should be integrated into a state-of-the-art angiographic system for proper application and utilization. This results in improvements in both efficiency and diagnostic accuracy. However, from the physician's viewpoint, the proper use of a DSA imaging facility mandates not only an understanding of angiographic principles as applied with conventional film-screen systems but also an in-depth understanding of the factors that affect DSA performance. In particular, factors affecting spatial resolution and contrast sensitivity are crucial. This knowledge has to be applied interactively and "on-line" to achieve optimal IA-DSA image quality.

Angiography↗
PubMed1984

Intravenous DSA examination of patients with suspected cerebral ischemia.

We analyzed the role of intravenous digital subtraction angiography (DSA), with neck and intracranial views as a definitive pretherapy study, in patients who had symptomatic cerebral ischemia. Eighty-six patients, 25 of whom had subsequent carotid thromboendarterectomy, were examined. An adequate pretherapy intravenous DSA study allowed us to define each carotid bifurcation as either normal, having insignificant stenosis, or having significant stenosis, and the examination excluded significant tandem stenosis in the intracranial internal carotid arteries. Adequate pretherapy intravenous DSA studies were obtained in 73% of patients, including 50% of those in the presurgical group. Selective carotid arteriography was not required in these patients. Inadequate presurgical studies were predominantly due to plaque misregistration, inadequate projection, and superimposition that obscured the proximal internal carotid arteries. Selective carotid arteriography was performed in these patients prior to surgery. Inadequate studies prior to initiation of medical therapy were predominantly due to soft tissue misregistration artifact, and superimposition. Intravenous DSA is a valuable screening test and can be used to guide therapy in the majority of patients who have symptomatic cerebral ischemia.

Arterial Occlusive Diseases↗
PubMed1984

Primary biliary carcinoma: CT evaluation.

Fifty-three patients with documented primary biliary carcinoma were studied with computed tomography. Twenty-six patients had gallbladder carcinoma and 27 patients had carcinoma of the biliary ductal system. Ninety percent of patients with gallbladder cancer had an intraluminal mass. Local invasion into the liver was common. The majority of patients with biliary ductal carcinoma had dilated bile ducts, while only 50% of patients with gallbladder cancer had biliary ductal dilatation. The most common location of tumor involving the extrahepatic biliary ductal system was the distal common bile duct. This occurred in eight patients out of 27, or 30% of the cases.

Adult↗
PubMed1983

Dynamic computed tomography and duplex ultrasonography: adjuncts to arterial portography.

The applications and limitations of contrast enhanced computed tomography (CT) in defining the extrahepatic portal system is discussed in the context of three separate cases in which the CT examination was used as an adjunct to an incomplete arterial portogram examination. Dynamic CT may be useful when excessive contrast dilution precludes the visualization of major venous structures during arterial portography. Real-time/pulsed Doppler ultrasonography is another complementary test but more limited in application than dynamic CT. Patency and flow direction in the proximal splenic vein, portal vein, and hepatic vein can be defined by the ultrasonic technique.

Adult↗
PubMed1983

Dynamic computed tomography and pulsed Doppler ultrasonography in the evaluation of splenorenal shunt patency.

Dynamic computed tomography (CT) and real-time/pulsed Doppler ultrasonography were performed in 13 patients following a distal end-to-side splenorenal shunt (Warren procedure). The results were correlated with angiography. The anastomotic site was demonstrated by CT in all patients. Coincident enhancement of the distal splenic vein and left renal vein as demonstrated by dynamic CT was an accurate predictor of shunt patency. Ultrasound studies were performed using a transsplenic coronal imaging approach. Although the proximal splenic vein and left renal vein could be identified, it was not possible to directly evaluate the anastomotic site in any patients. Dynamic CT evaluation of splenorenal shunts may be a useful technique for monitoring shunt patency during long term follow-up and for evaluating patients who later rebleed.

Adult↗
PubMed1983

Contrast enhancement technique for dynamic hepatic computed tomographic scanning.

A study comparing precontrast and survey postcontrast dynamic computed tomographic (CT) scanning was performed on 60 patients who had suspected hepatic metastases. An incremental dynamic technique was used during and following a 50-g iodine load administered over two minutes. The survey postcontrast dynamic technique was superior in both sensitivity and contrast differentiation and yielded no known false-negative examinations. No postprocedure renal dysfunction was observed. High-dose contrast-material delivery in conjunction with incremental dynamic CT scanning appears to be the most suitable technique for performing postcontrast hepatic CT examinations.

Diatrizoate↗
PubMed1983

Work in progress: temporal energy hybrid subtraction in intravenous digital subtraction angiography.

A preliminary investigation of the feasibility and practical clinical utility of combined temporal energy (hybrid) subtraction for intravenous digital subtraction angiography (DSA) was performed in 19 selected patients. Studies of carotid, aortic arch, pulmonary, and aortorenal vessels were obtained. Soft-tissue misregistration artifacts were effectively removed with hybrid subtraction. Image integration was used to produce a signal-to-noise ratio equivalent to that of single frame temporal subtraction. Diagnostic improvements were produced in 20% of the examinations. Hybrid subtraction techniques resulted in an average increase of incident radiation dose to the skin of 15%.

Angiography↗
PubMed1983

Dissecting aortic aneurysms: accuracy of computed tomographic diagnosis.

During a three-year period, fifty patients were evaluated for the possibility of dissecting aortic aneurysm using high-resolution computed tomography (CT). The diagnosis of dissection was made if two contrast-medium-filled channels were identified within the aortic lumen. Eighteen patients were diagnosed with CT as having dissecting aortic aneurysms. Eight patients were evaluated postoperatively and five of these patients had persistence of the double channel. Twenty-four patients had no evidence on CT of aortic dissection. Follow-up was obtained in all patients. There were no known false-negative diagnoses and one false-positive diagnosis. High-resolution CT offers an accurate, noninvasive means to evaluate patients for suspected dissecting aortic aneurysms.

Aortic Dissection↗
PubMed1983

Digital subtraction angiography of the portal venous system.

Venous-phase arteriography after celiac or superior mesenteric artery injection is the most common technique used to demonstrate portal venous anatomy, flow direction, and portal systemic shunts. Large-volume contrast material injections and intraarterial vasodilators or balloon occlusion technique are required for optimal examinations using film-screen recording. A technique for performing venous-phase arteriography with digital subtraction imaging after celiac and superior mesenteric artery injection is described. The major advantage of intraarterial digital subtraction technique in comparison to film-screen recording is sensitivity to intravascular iodine with a consequent reduction in contrast material load and examination time. Technical success is limited only by motion artifact and should approximate the 80%-90% figure achieved for intravenous digital subtraction angiography of the aortorenal vessels.

Diatrizoate↗
PubMed1983

Misdiagnosis of pericardial cyst by echocardiography and computed tomography scanning.

We saw a patient who had clinical features of right-sided heart failure. Echocardiography and computed tomography findings were incorrectly interpreted as demonstrating an intracardiac mass. At surgery, a pericardial cyst externally compressing the right ventricular cavity was found. We conclude that, although noninvasive tests may play a valuable role in evaluating intracardiac masses, interpretation may be difficult and misdiagnoses are possible.

Aged↗
PubMed1982

Renal fascial thickening in pancreatitis.

The incidence of renal fascial thickening in pancreatic inflammatory disease was evaluated by computed tomography. A total of 71 cases including chemical, acute complicated, and acute and chronic uncomplicated pancreatitis were retrospectively evaluated for thickening of the renal fascia. Renal fascial thickening is demonstrated in the majority of patients with complicated and uncomplicated pancreatitis. It is not demonstrated in cases of chemical pancreatitis. Renal fascial thickening is nonspecific and seen with inflammatory, malignant, and traumatic processes, but it is a valuable adjunctive sign of pancreatic inflammatory disease.

Fascia↗
PubMed1982

Ultrasonic visualization of the pancreatic duct.

The frequency and significance of pancreatic duct visualization by ultrasonography were correlated with endoscopic retrograde cholangiopancreatography or pancreatic computed tomography. The normal pancreatic duct was found to have parallel walls and to be less than 2 mm in internal diameter in the region of the body of the pancreas. The abdominal pancreatic duct had an internal diameter of 2 mm or greater or had walls that were nonparallel or convex outward (focal dilatation or beading). Pancreatic ducts were identified in approximately one-half of all patients evaluated. Failure to visualize an abnormally dilated pancreatic duct was secondary to distortion of pancreatic anatomy from large or multiple pseudocysts, calcific deposits within the pancreas, or technically poor visualization of the pancreas.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1982

Porta hepatis: sonographic discrimination of bile ducts from arteries with pulsed Doppler with new anatomic criteria.

Duplex scanning of the porta hepatis was performed in 71 patients, and the identity of the common duct and hepatic artery were confirmed by characteristic pulsed Doppler signals or by tracing structures to known landmarks. In 59% of patients, the hepatic artery was as large or larger than the adjacent normal bile duct, suggesting that the two structures may occasionally be confused. Sonographic signs that help to confirm or support the differentiation of arteries from ducts include observation of intrinsic pulsations of arteries, indentation or displacement of structures by arteries, change in the caliber of bile ducts during real-time examination, and the orientation, contour, caliber, and curvature of the tubular structures of the porta hepatis. Simultaneous identification of the hepatic artery and extrahepatic bile duct using pulsed Doppler or these newly described anatomic criteria improves the diagnostic accuracy of sonography of the porta hepatis.

Adult↗
PubMed1982

Comparison of pre- and postcontrast CT in hepatic masses.

A comparison of hepatic computed tomography (CT) before and after administering intravenous contrast material was performed 85 times on 81 patients suspected of having hepatic mass lesions. Both pre- and postcontrast computed tomography were sensitive and specific in over 88% of cases, with no statistical difference in accuracy between the techniques. However, postcontrast scans were generally preferred because of increased diagnostic confidence and improved characterization of associated abnormalities. The recent advent of rapid sequential scanning after intravenous administration of a large volume of contrast material seems to further improve diagnostic confidence. When high-resolution CT equipment is used, postcontrast CT alone is the preferred method for CT evaluation of patients with suspected liver lesions.

Adult↗
PubMed1982

Evaluation of renal transplants with pulsed Doppler duplex sonography.

Sixty-seven patients who had had renal transplants were examined 184 times by pulsed Doppler duplex sonography, and a pulsed Doppler index (PDI) was developed to provide an indicator of renal blood-flow patterns. Arterial Doppler signals were obtained from transplant vessels during all technically satisfactory examinations of viable allografts; interpretations of transplant status based on the PDI and clinical function studies agreed with radionuclide renogram diagnoses in more than 90 per cent of cases when both sonograms and renograms were available. Pulsed Doppler analysis may differentiate between arterial occlusion and severe rejection and may decrease the need for radionuclide studies in some patients.

Graft Rejection↗