Quality improvement in diagnostic radiology.
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Biomedical subjects
Publications and source records attributed to P N Cascade.
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The systemic hematological effects of low-dose intraarterial streptokinase were studied in 12 patients with angiographic evidence of thrombosis. Streptokinase was administered at 5,000 U/hr; this rate was increased in the absence of clinical response or a systemic effect, which was defined as a thrombin time greater than twice that of the control time and/or a fibrinogen concentration less than 30% that of the control concentration. Eight patients experienced a systemic effect with final infusion rates of 7,500 to 20,000 U/hr over 20 to 72 hours, while 4 patients had no evidence of a systemic effect at 5,000 to 10,000 U/hr over 18 to 138 hours. A systemic effect could not be predicted based on infusion rates or durations, and the presence of a systemic effect was not predictive of hemorrhagic complications or thrombolytic effect in our small series. These results suggest that a systemic effect is frequently encountered with this form of therapy and is of uncertain clinical relevance.
Thirty-six patients with variant angina pectoris (VAP) were analyzed to investigate whether the mechanism underlying dysrhythmia is related to coronary occlusion or reperfusion. Fifteen of the 36 patients demonstrated dysrhythmias (42%). Twelve of 15 patients (80%) experienced dysrhythmia prior to the acme of ST-segment elevation (occlusive dysrhythmia), and those of tachyarrhythmia type were characterized by the presence of ventricular premature beats initially isolated, increasing in frequency, and preceding the more malignant forms of dysrhythmias, such as ventricular tachycardia or ventricular fibrillation. The occlusive dysrhythmias included ventricular dysrhythmia (ventricular premature beats, ventricular tachycardia, slow ventricular tachycardia, ventricular fibrillation) in eight patients and conduction abnormalities (second- and third-degree AV block, left posterior fascicular block) in four patients. Thirteen episodes of VAP were fully recorded electrocardiographically. The average time to onset of dysrhythmia, after the beginning of ST-segment elevation, was 4.94 minutes +/- 1.52. The duration of the episodes without dysrhythmia was 0.86 minute +/- 0.53. The "reperfusion dysrhythmia" occurred in three patients (20%) and was characterized by the appearance of isolated couplets of ventricular premature beats, ventricular tachycardia, or ventricular fibrillation without prodromal ectopic activity. The dysrhythmia occurred in one patient during the resolution of ST-segment elevation and in two patients within seconds of ST-segment normalization. We conclude that the occlusive related dysrhythmias are the most important mechanism in VAP. They are dependent on the duration of the ischemic episode.
Patients with mitral valve disease and extreme enlargement of the left atrium usually exhibit significant decrease in chamber size following corrective mitral valve surgery. We describe a patient in whom extreme right and left atrial enlargement developed, and progressed following mitral valve replacement, with no evidence of prosthetic valve malfunction or tricuspid valve disease.
Retrospective and prospective analyses of chest radiographs of patients following coronary artery bypass surgery were undertaken. Left lower lobe pulmonary infiltrate and/or atelectasis developed in 13 of 40 (32.5%) patients who were operated upon without topical cooling of the heart with ice, and in 77 of 122 (63.1%) patients in one group and 34 of 40 (85.0%) patients in another group who were operated upon with topical cooling of the heart with ice. This difference was highly significant (p less than 0.001). Of the patients in one group in whom left lower lobe abnormality developed, 69.2% had paralysis or paresis of the left hemidiaphragm. It is evident that application of ice to the phrenic nerve can lead to temporary paralysis of the left of the diaphragm, with subsequent development of left lower lobe pulmonary infiltrate and/or atelectasis.
The echocardiographic features of patients with parachute mitral valve have revealed the combination of an early systolic movement of the mitral valve and late systolic prolapse. Cross-sectional echocardiographic and angiographic studies showed that the early systolic anterior motion was produced by the presence of a flail scallop of the anterior mitral leaflet in the left ventricular outflow tract.
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A study of single-plane right anterior oblique left ventricular angiography was undertaken to determine the importance of obtaining correct positioning of a magnification grid and to develop a simple but accurate technique to minimize magnification errors. Theoretical and experimental volume determinations demonstrated 3% to 28% volume errors for grid placement errors ranging from 1 centimeter to 5 centimeters. An experiment was designed whereby cross table lateral radiographs of the chest were taken during contrast injections of the left ventricle. The relative position of the left ventricular center was found at a point 66% of the distance from the anterior to the posterior margin of the heart. Finding this point on noncontrast lateral films of the chest for positioning of a square centimeter grid should yield a more accurate determination of the magnification factor than other current emperic methods.
A catheter-mounted polyurethane cusp was designed to act as a temporary prosthetic aortic valve in the ascending aorta. Acute aortic insufficiency was created in 15 dogs by transventricular tearing of the two aortic valve leaflets with a wire hook. Hemodynamic variables were measured during aortic insufficiency and with the prosthetic valve in place. Comparison of the values showed that the prosthesis functioned as a competent aortic valve. Aortic diastolic pressure increased by 62 +/- 42%, pulse pressure was lowered by 44 +/- 9%, and left ventricular end-diastolic pressure decreased by 45 +/- 18%. Neither cardiac output, coronary blood flow, nor peak systolic pressure was significantly altered. The observed hemodynamic improvement and the simplicity of the design and application suggest that the prosthetic aortic valve may be applicable in the temporary treatment of decompensated aortic insufficiency.
Nineteen patients in acute left ventricular power failure following acute myocardial infarction were given support with intraaortic balloon pumping and underwent cardiac catheterization. Hemodynamic response to disastolic augmentation, results of left ventriculography, and observations of selective coronary arteriography were evaluated to determine which patients could survive without operation, which would require operation to survive, and which could be predicted not to survive operation. Of ten patients who underwent operation, three were long-term survivors. Two patients predicted to have a good prognosis without surgery did survive. Of three patients who had been determined to require operation but not undergo it, two died in the hospital and one a month later. The four patients whose conditions were considered inoperable died in the hospital. The results indicate that current methods of predicting the need for corrective surgery are relatively accurate and that the rate of survival in surgically treated patients may be increased.
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We report 1 case of abdominal wall cellulitis and sepsis which developed following percutaneous placement of a Cope catheter for cecal decompression in a patient with Ogilvie's syndrome. This case highlights that further laboratory investigation and clinical evaluation are needed to determine the safest and most efficacious technique of percutaneous drainage.
Primary thymic carcinoma is a rare neoplasm that in contradistinction to thymoma, is not supposed to be associated with a paraneoplastic syndrome. A 73-year-old man, with new onset of disorientation, was found to have an elevated serum calcium level as the cause. Computed tomography demonstrated a mediastinal mass, pericardial invasion, and metastases to the lung. Examination of a biopsy specimen revealed thymic squamous cell carcinoma. Thus, a paraneoplastic syndrome, in this case hypercalcemia, does not exclude primary carcinoma of the thymus.
Physicians are generally aware of the use of bypass pumps during open heart surgery and of the intraaortic balloon pump in treatment of cardiogenic shock. In selected research centers, other advanced methods of cardiopulmonary support are being introduced. Some devices such as the total artificial heart fail clinical trials and disappear from use. Others, like some of the partial artificial hearts, improve outcomes and gain wider clinical use. Some devices temporarily support the circulation in patients recovering from acute circulatory collapse, whereas others provide longer-term circulatory support for patients awaiting transplantation. Permanently implanted devices provide circulatory assistance in cases of chronic, debilitating heart failure. Technology to support lung function in the setting of acute respiratory failure, allowing healing to take place, is also under study. Radiologists should be familiar with the operating principles and radiographic appearances of these emerging techniques to maintain their role as consultants to cardiopulmonary specialists.
The American College of Radiology Task Force on Appropriateness Criteria was developed in 1993 with the major objective of creating the most credible patient care guidelines possible. Oncology-related clinical conditions addressed by the Task Force pertain to the diagnosis of suspected disease and, after disease is diagnosed, its staging, treatment, and follow-up to determine the effectiveness of therapy.
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