Faculty Bibliography

This article describes a patient with renal cell carcinoma and massive tumor extension into the inferior vena cava who experienced sudden tachypnea and subsequent cardiopulmonary arrest. Transesophageal echocardiography was used to diagnose a massive tumor embolus to the pulmonary artery that was subsequently confirmed at autopsy. Transesophageal echocardiography provided a rapid bedside diagnosis of this unusual entity in an acutely ill patient. This technique may prove more widely applicable in the evaluation of patients with suspected pulmonary embolus, whether neoplastic or thromboembolic

Stroke is an especially serious complication of cardiopulmonary bypass with an incidence of 2% to 5%. This prospective study used transesophageal echocardiography (TEE) in 97 patients more than 65 years of age (mean age, 73 years) to identify those at high risk for aortic atheroemboli. The atheromatous disease of the aorta was graded by TEE: grade I = minimal intimal thickening (n = 29); II = extensive intimal thickening (n = 33); III = sessile atheroma (n = 15); IV = protruding atheroma (n = 10); V = mobile atheroma (n = 10). Clinical evaluation was also performed by intraoperative aortic palpation. Four patients who were graded as having normal aortas by palpation had intraoperative strokes. In contrast, 3 of these 4 patients were in grade V on TEE. The relationship of TEE to incidence of stroke was statistically significant (p less than 0.006), whereas there was no significant correlation between clinical grade and stroke incidence. Four of 10 TEE grade V patients were treated with hypothermic circulatory arrest and aortic arch debridement, and none suffered strokes. The other 6 patients were treated with standard techniques, and 3 had strokes. These results suggest that patients with mobile atheromatous disease are at high risk for embolic strokes that are not predicted by routine clinical evaluation. Selective use of circulatory arrest in the presence of TEE-detected mobile arch atheromas may reduce the risk of intraoperative stroke

An unusual right atrial mass was visualized on the transthoracic and single planar transesophageal echocardiograms of a young female patient. Biplane transesophageal echocardiography, however, clearly demonstrated this structure to be a prominent Chiari network. Large eustachian valves and Chiari networks may mimic tumor or thrombus formation when conventional noninvasive diagnostic techniques are used. Multiplanar imaging can be essential in defining anatomical relationships of normal variant structures, eliminating concern for pathological entities and the need for further invasive work-up

An 18-year-old patient underwent repair of traumatic aortic pseudoaneurysm. Postoperatively, the physical examination showed hypertension with 30 mm Hg gradient between the upper and lower extremities. Doppler echocardiographic evaluation demonstrated a new (secondary) aortic coarctation at the site of the repair. Transesophageal echocardiography revealed the detailed anatomy and the cross-sectional area of the coarctation

We studied quantitatively the receptive-field properties of 74 units recorded from the representation of the central visual fields in the cat's lateral suprasylvian (LS) visual cortex. In agreement with previous workers, we found that LS receptive fields tended to be large and to lack discernible spatial structure. They resembled the complex receptive fields of areas 17 and 18 in their general organization. We examined the responses of these neurons to moving optimally oriented sinusoidal gratings that varied in spatial and temporal frequency of drift. Most LS neurons were selective for the spatial frequency of sinusoidal gratings; 7% responded to all spatial frequencies below a cutoff value. In agreement with previous reports, the optimal spatial frequencies for LS neurons covered a wider range than is seen in either area 17 or 18 alone (0.05-1 cycle/deg), but are certainly included in the range covered by both these afferent areas. Individual neurons in LS responded to a range of spatial frequencies broader than is typical for neurons in areas 17 and 18. The effect of varying the drift rate of otherwise optimal gratings was similar in LS to that reported for areas 17 and 18. Most neurons were optimally responsive to drift rates between 0.5 and 4 Hz, and resolved frequencies as high as 10-30 Hz. A few neurons had optima higher than 6 Hz and resolved frequencies in excess of 30 Hz. We conclude that the receptive fields of LS neurons reflect rather closely the properties of their afferents from areas 17 and 18.(ABSTRACT TRUNCATED AT 250 WORDS)