Biomedical subjects
Publications and source records attributed to R L Soulen.
This study suggests that the use of MRI together with echocardiography may reduce the need for serial cardiac catheterizations in the postoperative care of children with complex congenital heart disease.
Twenty-five patients with Marfan syndrome underwent computed tomography (CT) and magnetic resonance (MR) imaging. MR images were interpreted in blinded fashion and then the results were compared with findings from CT scans. MR imaging was found to be equivalent to CT in the depiction of aortic, dural, and hip abnormalities in patients who had not undergone surgery. MR imaging was superior to CT in evaluation of postoperative patients because the artifact produced by Bjork-Shiley or St. Jude valves precludes adequate evaluation of the aortic root on CT scans, while producing only a small inferior field distortion, a "pseudo-ventricular septal defect," on MR images. The absence of radiation exposure is another significant advantage for the relatively young Marfan syndrome population, who require serial studies. MR imaging is the modality of choice for evaluation and follow-up of patients with Marfan syndrome and offers an appropriate means of screening their kindred.
This is a prospective analysis of patients undergoing 34 treatments for arterial thromboses and emboli with intra-arterial thrombolytic therapy. These included acute arterial thromboses, graft thromboses, arterial emboli and pulmonary emboli. Twenty-seven of 34 patients treated had evidence of lysis, 14 had complete lysis, 13 had partial lysis and seven had no lysis. Both patients with occlusions for longer than three weeks failed to respond to treatment. Thirty-two patients presented with ischemia of the extremity. Twenty-four of 32 patients had limb salvage with eight subsequently undergoing amputation. No patient who was treated for claudication or who had a patent popliteal artery distal to the acute thrombosis failed to respond. Extensive tibioperoneal occlusion generally responded poorly compared with femoropopliteal or more proximal thrombi. Complications are divided into direct (drug related) and indirect (technique related). Four of 34 patients had an extensive hemorrhagic event with two suffering intracranial bleeding who ultimately died. All of the patients with extensive hemorrhagic episodes had serum fibrinogen levels of less than 50 milligrams per cent. During infusion, extensive distal emboli occurred in three with two of these patients requiring thrombectomy; one instance resolved with infusion. Minor distal emboli occurred in three and all resolved with continued infusion. We believe that intra-arterial thrombolytic therapy is a valuable adjunct in the treatment of acute arterial occlusion. The local infusion of lytic agents appears to be more efficient than systemic therapy. The tip of the infusion catheter should be placed into the thrombus for optimal lysis, but not advanced too far. The fibrinogen level is a sensitive indicator of systemic lysis and should be maintained above 50 milligrams per cent. Systemic lysis is obtained even with low dose infusion when therapy exceeds six hours. Intra-arterial infusion of thrombolytic agents can be performed safely in the immediate postoperative period as well as intraoperatively if specific guidelines are followed. Patients with massive unilateral pulmonary embolism can be efficiently treated with intra-arterial lytic therapy.
Computerized tomography (CT), ultrasound, and angiography have been used for staging renal cell carcinoma. CT has proven to be the most reliable and sensitive of these techniques. Magnetic resonance (MR) has emerged recently as a viable alternative imaging modality. Five patients with renal cell carcinoma and suspected caval involvement were evaluated by CT, ultrasound, and MR. Caval extension and the differentiation of intra-versus retrocaval tumor was seen with greater clarity on MR scans; perinephric extension was seen equally well with both modalities. The primary tumor itself was better defined with CT. In patients with equivocal findings regarding the renal veins or inferior vena cava, MR is a valuable adjunct in preoperative evaluation. In patients at high risk for contrast administration, MR is the staging modality of choice.
Gated magnetic resonance imaging of 5 patients with suspected constrictive pericardial disease was performed using a superconducting magnet operating at 0.35 Tesla. Results were compared with those of echocardiography and hemodynamic measurements in all patients, with chest films in 5, computerized tomography in 2 and with histologic findings in 3. Pericardial thickness exceeded 5 mm in 4 patients and was 5 mm in 1 patient. Absence of magnetic resonance signal from the thickened pericardium was observed with extensive calcific deposits, and increased intensity of the thickened pericardium was associated with inflammatory disease. Dilatation of the right atrium, venae cavae and hepatic veins, and right ventricular narrowing was observed in all patients. The ventricular septum was straight in all patients. Magnetic resonance imaging allows both measurement of pericardial thickness and depicts internal cardiac anatomy without exposure to radiation or use of contrast medium. Satisfactory imaging with a large field of view can be performed in the presence of lung disease, thoracic deformity or surgical "hardware"--conditions that limit echocardiography and computerized tomography. The inherently 3-dimensional data permit imaging in any plane without loss of resolution. Thus, magnetic resonance appears to be the noninvasive method of choice for the diagnosis of constrictive pericardial disease.
A case of a type of popliteal entrapment syndrome that does not include an anomalous course of the popliteal artery is presented. In situ thrombosis secondary to entrapment-induced stasis was the presumed cause of ischemic symptomatology. Thorough knowledge of the possible causes of entrapment and biplane angiography (of the popliteal artery) with provocative maneuvers often are required for diagnosis. As in our patient, surgical release of the entrapment can lead to complete resolution of symptoms.
A renal abscess secondary to obstruction and infection of a pyelocaliceal diverticulum was managed successfully percutaneously. The diverticulum spontaneously re-established communication with the renal collecting system. No surgery was required and the patient was well 2 years later.
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To evaluate the safety of magnetic resonance (MR) imaging of prosthetic heart valves, nine different synthetic and tissue valves were studied ex vivo. Deflection was measured in 0.35-tesla (T) and 1.5-T superconducting magnets and at the edge of the bore of a 2.35-T electromagnet in field gradients of 5, 1.1, and 6.3 mT/cm, respectively. No valve deflected in the 0.35-T magnet; six synthetic valves deflected 0.25 degrees-3 degrees in the 1.5-T magnet; all valves deflected 1 degree-27 degrees at the edge of the 2.35-T magnet. Each valve was then submerged in a vial of water and the temperature was measured immediately before and after each of two spin-echo imaging sequences in the two superconducting magnets. No significant temperature rise followed exposure in either magnet. Image distortion varied from negligible to severe in both imagers; magnitude of distortion paralleled magnitude of deflection. These data suggest that patients with present-day prosthetic heart valves can be safely imaged in present-day MR imagers and that prosthesis-induced artifacts will not interfere with interpretation in most instances.
Impedance plethysmography (IPG) has a reputed sensitivity of 95% in the detection of proximal, clinically significant deep venous thrombosis (DVT). A review of the radiologic studies of 100 consecutive patients who underwent both venography and IPG showed venographic evidence of proximal DVT in 40 patients. The IPG was negative in 15 (38%) of these 40 cases. The specificity of the IPG was 83%. The predictive value of a negative study, with this 40% prevalence of DVT, was 77%. These disturbing results indicate a continuing role for venography in the workup of DVT.
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Two-dimensional echocardiography, Doppler ultrasound, and magnetic resonance imaging (MRI) have greatly enhanced the noninvasive diagnosis of congenital anomalies of the thoracic aorta. Both sonic and magnetic resonance techniques can obviate preoperative invasive studies, and both provide an excellent means of follow-up. Ultrasound will likely remain the most valuable modality in neonates, while MRI promises to make an important contribution in older children and adults.
Correction of structural defects of the heart associated with cyanotic heart disease often requires rerouting of systemic venous return into the pulmonary arteries and pulmonary venous return into the ventricles. Preliminary experience suggests that magnetic resonance imaging, through its superior depiction of the resultant complex anatomy, provides important supplemental information to echocardiography. Together, these noninvasive techniques may lessen the present need for repeat catheterization in children with surgically corrected cyanotic heart disease.
A solitary pulmonary nodule was shown by dynamic computed tomography to be vascular, to be enhanced during the pulmonary venous phase, and to be in continuity with the left inferior pulmonary vein. The diagnosis of pulmonary varix was confirmed by pulmonary angiography, an invasive procedure that can be avoided in the future.
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Metastatic disease to the heart is a relatively common entity that may involve the pericardium, myocardium, or endocardium singly or in combination. Echocardiography, particularly two-dimensional imaging, is the most sensitive tool for detecting metastatic disease to the heart. Simple, safe, and noninvasive, it can provide better anatomic detail than can more invasive studies. This information is helpful not only in diagnosis and treatment planning, but in differential diagnoses of unusual cardiac configurations and guidance for pericardiocentesis of loculated effusions.
We report successful lysis of acute arterial calf thrombosis by intra-arterial streptokinase infusion seven hours after retroperitoneal dissection and repair of an ipsilateral common femoral artery laceration. No systemic effects or complications developed. Local intra-arterial thrombolytic therapy is more effective and safer than intravenous systemic therapy and may now be considered in the immediate postoperative period, providing the drug is delivered downstream from the operative site.
With two dimensional echocardiography, a left atrial mass was detected in 19 patients. Of these, 10 patients with rheumatic mitral stenosis had a left atrial thrombus. The distinctive two dimensional echocardiographic features of left atrial thrombus included a mass of irregular nonmobile laminated echos within an enlarged atrial cavity, usually with a broad base of attachment to the posterior left atrial wall. Seven patients had a left atrial myxoma. Usually, the myxoma appeared as a mottled ovoid, sharply demarcated mobile mass attached to the interatrial septum. One patient had a right atrial angiosarcoma that appeared as a nonmobile mass extending from the inferior vena caval-right atrial junction into the right atrial cavity. One patient had a left atrial leiomyosarcoma producing a highly mobile mass attached to the lateral wall of the left atrium. M mode echocardiography detected six of the seven myxomas, one thrombus and neither of the other tumors. Thus, two dimensional echocardiography appears to be the technique of choice in the detection, localization and differentiation of intraatrial masses.