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Biomedical subjects

W D Foley

Publications and source records attributed to W D Foley.

At least 73 records · Page 4Linked to original sources

Digital subtraction angiography of the extremities using table translation.

Digital subtraction angiography (DSA) of the extremities has been performed with both intravenous and intraarterial injections of contrast material. Intravenous studies are usually site specific and are limited by contrast material load; a complete intraarterial study with multiple injections of contrast material may be time consuming. A feasibility study to evaluate a DSA technique that would allow table translation and imaging of two contiguous regions following a single injection of contrast material--bolus-chase DSA--was performed. Forty-five examinations were performed, 13 intravenously and 32 intraarterially. Twelve intravenous and 16 intraarterial DSA examinations were totally satisfactory. Inadequate studies were predominantly caused by slow arterial clearance of contrast material in the distal calf and by operator error. Compared with conventional DSA, anatomic studies of lower-extremity vessels could be obtained faster and with lower contrast material loads using bolus-chase DSA.

Adult

Evaluation and treatment of intraabdominal bilomas.

In a 3-year period, 21 intraabdominal bilomas developed in 18 patients. Fifteen of the patients had a solitary biloma, and the other three patients each had two separate concurrent bilomas. The major cause of biloma formation was postoperative bile leakage from a bile duct after laparotomy done primarily for surgery on the gallbladder or liver. Maximal diameter of the bilomas in the transaxial plane ranged from 2 to 19 cm. Sixteen of the bilomas were in the right upper quadrant, and five were in the left upper quadrant. Two large right-sided collections extended caudally into the lower abdomen. The contours of the bilomas were configured by the diaphragm, mesenteries, liver, and other abdominal organs. On CT and sonography, the bilomas were invariably well demarcated, but most did not have an identifiable capsule. CT did demonstrate a thin rim on four bilomas and a thick rim on one. In 19 bile collections, the CT numbers were less than 20 H. The combination of the clinical history, the location, and the CT appearance of the lesion led to the correct diagnosis in each case. Percutaneous drainage was an effective form of therapy that often eliminated the need for surgical drainage.

Abdomen

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

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

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

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

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

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

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

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

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

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

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

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