The 24-hour Tl-201 image in dual isotope myocardial perfusion scintigraphy: clinical utility and prognostic significance.

This study assessed the effect on clinical decision making and the possible prognostic significance of the 24-hour Tl-201 image in patients undergoing Tl-201-MIBI dual-isotope myocardial scintigraphy. The records of all patients who underwent 24-hour Tl-201 imaging as part of their myocardial perfusion study from 1994 to 1996 were reviewed. Follow-up evaluations were obtained from the referring physician or by direct patient contact. Fifty-six patients underwent a total of 57 studies; four patients were lost to follow-up. Of the 53 studies evaluated, 29 showed no change between the standard rest images and the 24-hour images; these patients were reported to have myocardial scar. Of these 29 patients, 25 were treated medically without further evaluation; 24 of these 25 patients remained stable. Four of the 29 patients had further evaluation; 2 patients had coronary artery bypass graft, 1 had a stent placed, and 1 remained stable. Twenty-four patients showed definite improvement or normalization of their study results by 24 hours; they were reported as ischemic. Of these 24 patients, 11 were treated medically without further evaluation; 9 remained stable, whereas 2 had adverse events. The remaining 13 patients required further evaluation; 4 remained stable, whereas 9 had adverse events (4 = increasing angina; 1 = stent; 1 = rotoblator; 2 = percutaneous transluminal coronary angioplasty; 1 = death). Twenty-four-hour imaging contributes to clinical decision making and may identify a subset of patients at risk for subsequent complications.

Localization of a parathyroid adenoma by the addition of pinhole imaging to Tc-99m sestamibi dual-phase scintigraphy. Report of a case and review of experience.

Scintigraphy using Tc-99m has been shown to be highly sensitive in localizing abnormal parathyroid glands in patients with hyperparathyroidism. False-negative studies most often are attributed to glandular size or location. The authors report a case of negative parathyroid imaging using standard dual-phase technique, which was converted to a positive study by the addition of a pinhole view. During a 1-year period, the authors systematically added an anterior-pinhole image of the neck to all equivocal or negative Tc-99m studies. Five of 19 patient studies were pinhole-image positive and standard-image negative or equivocal. In selected patients undergoing Tc-99m scintigraphy for hyperparathyroidism, the addition of a pinhole view may enhance study sensitivity and the confidence in interpretation.

The effect of thalamic stimulation in processing of verbal stimuli in dichotic listening tasks: a case study.

In dichotic listening tasks, the (dominant) right ear's superiority in processing verbal stimuli has been attributed to its direct anatomic connection with the left dominant hemisphere. The role played by extralinguistic factors, such as attention and functional tuning of the associated cortical structures, has not been carefully examined. This investigation was undertaken to evaluate the effects of the left thalamic electric stimulation on the processing (recognition and recall) of dichotically presented CVC verbal stimuli in a patient being treated for chronic pain. We report the positive effects of electric stimulation (confirmed by increased subcortical metabolic activity using SPECT, a brain imaging technique) on the processing of dichotically presented verbal stimuli.