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Biomedical subjects

C Cope

Publications and source records attributed to C Cope.

At least 37 records · Page 2Linked to original sources
PubMed1994

Life-threatening pulmonary emboli and cor pulmonale: treatment with percutaneous pulmonary artery stent placement.

Large, central bilateral pulmonary emboli led to cor pulmonale and severe hypoxemia in a patient who had recently undergone cardiac surgery. After percutaneous catheter fragmentation and thrombolysis of the emboli failed, the left and right interlobal pulmonary arteries were recanalized by placement of self-expanding Wallstent endoprostheses through the clots. Pulmonary perfusion was restored to the lower lobes, and the patient demonstrated rapid clinical improvement.

Coronary Artery Bypass↗
PubMed1994

Transjugular intrahepatic portosystemic shunt stenosis and revision: early and midterm results.

OBJECTIVE: The purpose of this study was to define the pattern, rate, and interval during which stenosis develops in transjugular intrahepatic portosystemic shunts (TIPS) and to assess the effect of revision in prolonging shunt patency. MATERIALS AND METHODS: TIPS were created in 100 patients during a 34-month period. Sixty-one shunt venograms were obtained in 38 consecutive patients between 1 and 24 months after TIPS placement. Eighteen patients were examined because of recurrent symptoms, and all 38 had routine follow-up. RESULTS: Stenoses attributed to neointimal hyperplasia developed within both the TIPS stent and the outflow hepatic veins. Stenoses of greater than 50% developed in 12 patients within 6 months of TIPS placement. In addition to focal stenoses, the outflow hepatic veins diffusely shrank an average of 51% in diameter. Thirty-six shunt interventions were required: eleven balloon dilatations and 25 placements of an additional stent. Life-table analysis showed that patency of the primary shunt was 75% at 6 months, 50% at 1 year, and 32% at 2 years. The primary-assisted patency of the shunt was 85% at 12 months after shunt creation. CONCLUSION: The results indicate that TIPS are prone to significant and frequent early stenosis, warranting follow-up within 3-6 months in all cases. Stenosis of the outflow hepatic vein is the most common cause of shunt malfunction. Revision of a shunt significantly prolongs shunt patency.

Catheterization↗
PubMed1994

Magnetic resonance angiography of the aorta, iliac, and femoral arteries.

BACKGROUND: Successful management of patients with peripheral vascular disease requires detailed vascular imaging, usually performed by contrast arteriography. Recently, magnetic resonance angiography (MRA) has been shown to be a noninvasive technique with greater sensitivity than contrast arteriography for detecting distal runoff vessels in patients with peripheral arterial occlusive disease. However, to supplant the need for contrast arteriography and provide a completely noninvasive evaluation of patients with occlusive disease, accurate imaging of the inflow vessels and the runoff vessels is necessary. METHODS: We used both conventional arteriography and MRA in preoperative studies of the aorta, iliac, and femoral vessels of 47 patients. Conventional arteriography and MRA studies were compared for their ability to detect vessel patency and the presence of hemodynamically significant stenoses. Independent interventional plans were developed based on the information provided by each technique. The findings of conventional and MRA studies were verified by intraoperative arteriography or direct operative exploration. RESULTS: Results of the two studies were identical in 41 (87%) of 47 patients or 600 (98%) of 614 segments imaged. MRA accurately detected patent and occluded arterial segments (sensitivity 99.6%, specificity 100%, positive predictive value 100%, negative predictive value 98.6%) and hemodynamically significant stenoses. Therapeutic plans based on either MRA or conventional arteriography were identical for each patient. CONCLUSIONS: MRA provides comparable results to contrast arteriography in the proximal arterial system and superior results for imaging the distal vasculature. This noninvasive technique may replace contrast arteriography in a large number of patients in the future.

Adult↗
PubMed1993

Lymphangiography as a staging tool for cervix cancer: limited value after hip arthroplasty.

Lymphangiography (LAG) is often used in the work-up of cervical carcinoma. A patient with a history of bilateral hip arthroplasty, who presented with Stage IIIB squamous cell carcinoma of the cervix, was sent for lymphangiography. The LAG was deemed suboptimal, most likely because of altered lymphatic drainage engendered by the previous orthopaedic procedures. As the American population ages and hip arthroplasty becomes more common, the value of LAG in such patients will need to be reconsidered.

Aged↗
PubMed1993

Magnetic resonance venography for the detection of deep venous thrombosis: comparison with contrast venography and duplex Doppler ultrasonography.

PURPOSE: Contrast venography is the gold standard for diagnosis in deep venous thrombosis (DVT); however, this technique is invasive and requires the use of potentially hazardous contrast agents. Although duplex Doppler ultrasonography is accurate in the evaluation of lower extremity DVT, it is less accurate in the assessment of the pelvic and intraabdominal veins. Magnetic resonance venography (MRV) has recently been developed, and our purpose was to determine whether MRV could accurately demonstrated DVT when compared with duplex scanning and contrast venography. METHODS: Eighty-five patients underwent contrast venography and MRV from the inferior vena cava to the popliteal veins to rule out DVT. Thirty-three of these patients also underwent duplex scanning. Blinded readings of these studies were compared for the presence or absence and extent of venous thrombosis. RESULTS: DVT was documented by contrast venography in 27 (27%) venous systems. Results of MRV and contrast venography were identical in 98 (97%) of 101 venous systems, whereas results of duplex scanning and contrast venography were identical in 40 (98%) of 41 venous systems. All DVTs identified by contrast venography were detected by MRV and duplex scanning. The discrepancies were due to false-positive MRV (3) and duplex scanning (1) results. When compared with contrast venography, MRV had a sensitivity of 100%, specificity of 96%, positive predictive value of 90%, and negative predictive value of 100%. For duplex scanning the sensitivity was 100%, specificity was 96%, positive predictive value was 94%, and negative predictive value was 100%. CONCLUSIONS: It is concluded that MRV is an accurate noninvasive venographic technique for the detection of DVT.

Humans↗
PubMed1993

Symptomatic peripheral vascular disease: selection of imaging parameters and clinical evaluation with MR angiography.

In the first phase of this study, seven healthy subjects underwent examination with two-dimensional time-of-flight (TOF) magnetic resonance (MR) angiography to develop a protocol for evaluation of peripheral arterial vasculature from the infrarenal aorta to the foot. In the second phase, 73 patients with symptomatic peripheral vascular disease underwent examination with both conventional contrast material-enhanced arteriography and two-dimensional TOF MR angiography to evaluate the clinical usefulness of MR angiography. Postinterventional and intraoperative angiography or direct surgical exploration was the standard of reference. In 32 patients, discrepancies occurred between findings on arteriograms and those on MR angiograms; most of these discrepancies were caused by improved depiction of runoff vessels on MR angiograms. The demonstration with MR angiography of blood vessels not seen on conventional arteriograms, unidentified stenoses, or misidentified blood vessels altered surgical management in 12 patients (16%). Metal-clip artifacts obscured clinically important disease on MR angiograms in two patients. It is concluded that two-dimensional TOF MR angiography is very useful in preoperative assessment of patients with severe peripheral vascular disease.

Adult↗
PubMed1993

Recurrent bleeding from anorectal varices: successful treatment with a transjugular intrahepatic portosystemic shunt.

Anorectal varices are portal-systemic collaterals commonly found in patients with portal hypertension. Although these varices rarely bleed, when bleeding does occur it may be massive and life threatening. Anorectal varices may be mistaken for hemorrhoids and there is no agreed upon method for their definitive diagnosis. Additionally, there is no standard therapy for bleeding anorectal varices, and when techniques designed for the control of hemorrhoidal bleeding are employed the results can be disastrous. We report here the first use of a transjugular intrahepatic portosystemic shunt (TIPS) for the permanent control of bleeding anorectal varices. Magnetic resonance imaging/magnetic resonance venography (MRI/V) was used as a non-invasive method for the identification of anorectal varices and to confirm the successful decompression of these varices with TIPS placement. MRI/V and TIPS may provide significant advances in the diagnosis and treatment of rectal variceal bleeding.

Female↗
PubMed1993

Magnetic resonance arteriography of the pelvis and lower extremities.

Reconstructive vascular surgery is the last resort for limb salvage in patients with vascular insufficiency. Planning the sites of arterial bypass grafts depends on an exact knowledge of the angiographic anatomy. Currently, conventional contrast angiography is the primary preoperative study for surgical planning. Recently, magnetic resonance (MR) arteriography has been shown to be an accurate technique for the evaluation of slow arterial flow in the lower extremities. The purpose of this review will be to show how MR arteriography can be used as both an adjunct to and in some cases instead of conventional angiography for the preoperative assessment of lower-extremity vascular reconstruction. The derivation of common artifacts, the many pitfalls of interpretation, and the evaluation of peripheral arterial occlusion and percentage stenosis will be discussed. MR arteriography of the lower extremities is an important advance for the noninvasive evaluation of disease of the peripheral vasculature.

Algorithms↗
PubMed1992

Magnetic resonance imaging of angiographically occult runoff vessels in peripheral arterial occlusive disease.

BACKGROUND: Bypass grafting to arteries of the lower leg has become standard surgical management of advanced peripheral vascular disease. Its success depends on identifying suitable distal vessels. Preoperative preparation includes imaging of the arteries of the lower leg, usually by conventional contrast arteriography. An alternative procedure, magnetic resonance (MR) angiography, has been successfully employed in patients with various cardiovascular diseases, but its possible value in patients with peripheral vascular disease has received little attention. METHODS: We used both conventional and MR angiography in preoperative studies of the lower-leg vessels of 23 patients (25 legs) with peripheral arteriosclerosis and arterial insufficiency, and developed independent therapeutic plans based on the information provided by each technique. When the plans differed, the interventional procedure judged more likely to save the limb was performed. The findings of conventional and MR angiography were verified by intraoperative arteriography, postinterventional arteriography, or direct operative exploration. RESULTS: MR angiography detected all vessels identified by conventional angiography, whereas conventional arteriography failed to detect 22 percent of the runoff vessels identified by MR angiography. The detection by MR angiography of vessels not identified by conventional angiography altered the surgical management of the disorders of four patients (17 percent) and guided successful bypass procedures. CONCLUSIONS: MR angiography is a noninvasive technique with greater sensitivity than conventional contrast arteriography for detecting distal runoff vessels in patients with peripheral arterial occlusive disease.

Aged↗
PubMed1992

Magnetic resonance angiography of peripheral runoff vessels.

Recent improvements in magnetic resonance imaging techniques have made magnetic resonance angiography (MRA) a very useful adjunct to invasive angiography. Fifty-five limbs in 51 patients with occlusive peripheral vascular disease were studied with both MRA and contrast arteriography. The magnetic resonance and contrast arteriograms were read by radiologists and surgeons and separate interventional plans were based on each study. The MRA findings differed significantly from those of conventional arteriography in 26 limbs (48%). In every case MRA visualized all of the same vessels and hemodynamic stenoses seen on the contrast arteriogram. In 48% of the cases, however, MRA revealed additional findings. Thus the discrepancies in the two studies were always the result of the failure of the arteriogram to reveal all of the patent vessels seen on MRA. The additional information provided by MRA resulted in alteration of the interventional plan in 11 cases (22%). In nine cases (18%) target vessels suitable for use in a limb-salvage procedure were identified by MRA, although they had been missed by conventional arteriography. In all of these cases, intraoperative arteriograms confirmed the suitability of these vessels for use in technically successful bypass procedures. In two cases (4%) additional information provided by MRA identified a target runoff vessel for bypass grafting that proved to be a better alternative than the one that would have been chosen on the basis of contrast arteriography.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Expandable intravascular catheter: percutaneous use for endoluminal retrievals.

Percutaneous use of an expandable vascular access catheter that can be deployed to temporarily occlude the entry vessel during retrieval of embolic material is described. The catheter was used to facilitate removal of two intraarterial objects, a postangioplasty free atheroma fragment and a displaced Gianturco coil. The expanded catheter end was equal to the arterial lumen, thus preventing distal embolization. The large distal lumen also facilitated plaque or foreign body removal by allowing deployment of various endovascular tools.

Aged↗
PubMed1991

Prognostic significance of nuclear DNA content in phaeochromocytoma.

Nuclear DNA content of 27 phaeochromocytomas was measured by image analysis of thin sections and monolayer smears of nuclei extracted from thick sections (cytospins) using archival paraffin-embedded tissue blocks. Recurrence was assessed on the basis of clinical follow-up or urinary catecholamine levels. The mean follow-up was 5.0 years, with a range of 4 months to 15 years. Although it is not possible to differentiate accurately malignant tumours using DNA analysis, prediction of benign tumours is possible. Using thin sections, all tumours were benign when the percentage of cells with a DNA content of 2.5 c (2 c = diploid) was less than 40% and the DNA content of 5 c was less than 4%. Using the cytospin preparation, all diploid tumours were benign. Thus, patients with diploid tumours may be saved intensive long-term follow-up. Aneuploid and tetraploid tumours, however, continue to require careful lifelong follow-up.

Adolescent↗
PubMed1991

Comparison of image analysis and flow cytometric determination of cellular DNA content.

A good correlation (r = 0.94) was obtained between the DNA indices (DI) using flow cytometry and image analysis of nuclei cytospins extracted from paraffin wax embedded tumour sections. Some of the limitations and problems associated with image analysis which came to light included an unacceptably high coefficient of variation (CV) and a "left-shift" in the DI in most DNA histograms obtained when using image analysis of 5 microns sections. In contrast, the DNA histograms generated using image analysis of cytospun nuclei from paraffin wax blocks were of good quality and similar to those obtained using flow cytometry. Variability in Feulgen staining was common and an important source of error despite rigorous control of the staining technique. This could be overcome by using internal controls such as fibroblasts rather than external controls (rat hepatocytes) to determine the diploid DI with image analysis. A thorough understanding and appreciation of the methodological problems associated with image analysis and flow cytometric determination of DNA content is required before these methods find widespread clinical application.

Adrenal Gland Neoplasms↗
PubMed1990

Drainage of bile ducts with an articulated T tube.

An articulated T tube has been devised to simplify percutaneous replacement. Because the crosspiece and the stem are held together with sutures, they can be aligned over a catheter and guide wire for atraumatic insertion into the bile duct. By pulling the suture taut, the articulated T tube is easily reconstituted. A second suture can be attached to the proximal limb of the crosspiece to extract it end-on at a latter date without enlarging the tract. This articulated tube has been found very useful for safely replacing T tubes that have fallen out of immature tracts (n = 2) and inserting T tubes in tumor-encased bile ducts either via an existing T-tube tract (n = 1) or transhepatically (n = 1). This design extends the usefulness of T tubes for efficient intra- or extrahepatic bile duct drainage.

Aged↗