Robert C. Meade

Jugular Venous Reflux in Cerebral Radionuclide Angiography

Jugular venous reflux was observed in six routine cerebral radionuclide angiograms. Repeat studies during a Valsalva maneuver failed to reproduce the reflux. In one case the reflux appeared to be related to the arm position; but in the other five cases, the cause remains unknown. Such reflux may be mistaken for superior vena cava syndrome or asymmetric carotid blood flow.

Organ-to-plasma uptake ratio of Tl-201 in rats injected at rest or after strenuous exercise

A comparison is made of relative organ-to-plasma Tl-201 uptake in rats at rest and after exercise (2 h swimming). Organs were obtained 1/2 or 3 h after Tl-201 injection. Under the four experimental conditions, the largest uptake was found in kidneys, heart and adrenal glands. The post-exercise to rest ratio of myocardial uptake is in agreement with clinical data reported in the literature. Two extensive tissues, skeletal muscle and fat, showed a remarkable increase of Tl-201 uptake at 3 h as compared to 1/2 h in both rested and post-exercised animals. During the same time interval there was a temporal “washout” of Tl-201 from heart (both at rest and after exercise) and kidney (after exercise only). The findings do not support the view of a delayed myocardial uptake phase of Tl-201 during which Tl-201 would be reintroduced into the blood from other body organs.

Pulsed Doppler studies in B-mode ultrasound scanning.

In B-mode ultrasound abdominal studies, vascular structures may be confused with other tissues. A pulsed Doppler unit was coupled to a B-mode scanner by attaching the Doppler transducer to the B-mode transducer. A standardization procedure was designed to assure that the ultrasound beams from the 2 transducers were properly aligned, and that the Doppler focusing was accurate. The Doppler signal may be obtained from any point in the B-mode image in order to differentiate vascular structure from other tissue types.

Technical Considerations in B-mode Scanning with an Aspiration Transducer

Proper orientation of the B-mode ultrasonic aspiration transducer is important for accurate imaging during aspiration biopsy. The transducer extension axis must be perpendicular to the plane of the scanning arm for accurate representation of reflector locations. Single pass scans without compound angulation of the transducer are recommended when perpendicularity is not absolute. A simple adaptor to maintain perpendicularity is described.