John A. Burdine

Restenosis after transluminal coronary angioplasty detected with exercise-gated radionuclide ventriculography

Forty-one patients were evaluated with exercise-gated radionuclide ventriculography before and within 4 days after successful transluminal coronary angioplasty and 4 to 12 months later. Patients were subgrouped according to the degree of restenosis demonstrated angiographically at 4 to 12 months (Group I [n = 23]: less than or equal to 20%; Group II [n = 10]: greater than 20% but less than 50%; Group III [n = 8]: greater than or equal to 50%). Patients with abnormal findings on gated radionuclide ventriculography (less than 5 point increase in ejection fraction or wall motion deterioration) early after angioplasty were eventually found to have a greater degree of restenosis than were patients with normal findings (41.2 +/- 30.3 versus 19.0 +/- 25.4% restenosis, p less than 0.0001). The accuracy of abnormal radionuclide ventriculography in predicting 50% or greater restenosis was 73% immediately after angioplasty and 77% at the time of follow-up angiography. Gated radionuclide ventriculographic results were abnormal in 5% of Group I patients compared with 75% of Group III patients (p less than 0.01) early after angioplasty; at late follow-up, they were abnormal in 27% of Group I patients compared with 88% of Group III patients (p less than 0.01). Group I patients had a greater increase in ejection fraction than did Group III patients at early (+11.3 +/- 7.5 versus + 3.5 +/- 6.5 points, p less than 0.01) and late (+11.8 +/- 7.8 versus -1.9 +/- 8.7 points, p less than 0.0005) follow-up. It is concluded that gated radionuclide ventriculography is useful in predicting coronary restenosis after transluminal coronary angioplasty.

ECG-gated emission computed tomography of the cardiac blood pool.

ECG-gated cross-sectional images of the cardiac blood pool were produced using a specially constructed emission computed tomographic scanner. A pair of large-field-of-view cameras were mounted in opposition in a gantry that rotates 360 degrees about the patient. The coordinates of each detected event, the output of a physiological synchronizer, and the position of the camera heads were input to a dedicated minicomputer which was used to produce the images. Display as a movie permitted evaluation of regional and global wall motion in cross section without the disadvantages of superimposed blood pools as obtained in nontomographic views.

Left ventricular performance during exercise in patients with left bundle branch block: Evaluation by gated radionuclide ventriculography

To investigate changes in left ventricular (LV) function during exercise in patients with left bundle branch block (LBBB), 22 patients without a history or physical findings of previous myocardial infarction or LV dysfunction were studied by gated radionuclide ventriculography (GRNV) at rest and during bicycle exercise. Coronary arteriography demonstrated greater than 75% diameter narrowing of at least one coronary artery in nine patients. Of the remaining 13 patients, GRNV demonstrated wall motion abnormalities in seven patients either at rest or with exercise. During exercise, mean ejection fraction (EF) did not increase in patients without coronary artery disease (CAD). Patients with CAD had a 12-point fall in mean EF with exercise. We conclude that LV reserve, as demonstrated by ability to increase EF with exercise, is impaired in patients with LBBB even in the absence of CAD or other underlying cardiac disease and that standard GRNV criteria to exclude the presence of CAD (a greater than five-point increase in EF with exercise and normal wall motion) are not strictly applicable in screening patients with LBBB.

99mTc-Human Albumin Microspheres (HAM) for Measuring the Rate of Gastric Emptying

The radiopharmaceutical HAM (99mTc-human albumin microspheres) was used to measure gastric emptying time in a series of 29 patients (normal, 9; duodenal ulcer, 7; gastric ulcer, 7; and gastric carcinoma, 6). The mean emptying rate in each group of patients was significantly different, as was the pattern of emptying. No overlap occurred in the T-50% results for one standard deviation. The physical properties of 99mTc-HAM permit the administration of relatively large amounts of the radionuclide, creating a high photon flux which results in excellent scintillation camera images. This technique is reproducible, and tests show less than 2% absorption of the radionuclide.

Correlations of systolic time intervals and radionuclide angiography at rest and during exercise

Systolic time intervals (STI) were correlated with radionuclide angiography studies (RAS) in 57 patients at rest, during maximal semisitting bicycle exercise, and at 4 minutes following the cessation of exercise. Eleven were judged as being free of coronary artery disease (group 1), while 14 had coronary artery disease without (group 2A), and 27 (group 2B) with a previous transmural myocardial infarction. For RAS, resting radionuclide ejection fraction (REF), the changes in REF and end-systolic volume, and the development of a wall motion abnormality at peak exercise were each highly correlated with the presence of coronary disease (p less than 0.001). The accuracy of STI parameters in predicting the presence of coronary disease was poor (less than 60%). Changes in end-diastolic volume (EDV) correlated significantly with PEP/LVET and LVET1 changes following exercise. Moreover, patients with an abnormal (greater than 25%) increase in EDV at peak exercise had a greater increase in LVET1 in the postexercise period (p less than 0.01). We conclude that STI is not accurate enough a predictor of coronary disease or left ventricular function to serve as a useful screening test. Changes in STI parameters appear to be more related to changes in ventricular volume than to ventricular function.

The Diagnosis of Pneumothorax by Ventilation-Perfusion Imaging

Two patients with pneumothorax had ventilation-perfusion studies to rule out the possibility of pulmonary embolism; the presence of air in the pleural space was not known to the authors when the study was analyzed. A typical ventilatory pattern characterized by small volume difference at total lung capacity followed by disproportionately greater decrease of the volume of the affected lung at tidal breathing was observed. In one case, the routine chest radiograph failed to demonstrate air in the pleural space. A similar volume difference between the two lungs was noted on the perfusion images.

Imaging Characteristics of a New Low-Energy Diverging∕Converging Collimator

A new, commercially available diverging∕converging collimator is evaluated. In the diverging mode, the collimator is approximately twice as efficient as the older medium-energy diverging collimator and offers equivalent resolution. Increased resolution in the converging mode indicates that the unit may be useful in imaging small superficial organs.

Determination of Bone Mineral Content Medicine Using the Scintillation Camera

A method has been devised for measuring bone mineral content using a scintillation camera with X/V locator and multimode analyzer. The bone is immersed in water and exposed to a 1251 or 241Am source. Transmission of photons through the bone (In) and through water (In*) are recorded, employing the 10a-channel analyzer in profile mode. The sum of the natural logarithms of the ratio In*/In across the width of the bone defines a “mineral index” proportional to the bone mineral content. Correlation of mineral index to calcium content in 13 bone phantoms was 0.997 with 1251 and 0.979 using 241Am, with a precision of 2% over a two-month period.

Renal accumulation of 67Ga-citrate

A 52-year-old female was admitted after a twq-day history of diarrhea, crampy abdominal pain, fever (to 104~ drenching sweats, cough, nausea, vomiting, and general malaise. Admission laboratory data revealed an elevated white blood cell count (WBC) with a marked left shift and a urinalysis showing trace protein, 3-5 WBC/HPF and numerous bacteria. Blood and urine cultures were positive for group D streptococcus (enterococcus). The patient was placed on intravenous ampicillin. An IVP revealed nonfunction of a slightly enlarged left kidney that was subsequently confirmed by abdominal CT. A gallium scan (Fig. 1) demonstrated intense diffuse accumulation throughout the left kidney at 4 and 48 hr. Subsequently, a left retrograde pyelogram demonstrated marked hydronephrosis with tight ureteropelvic junction (UP J) obstruction. After a full course of ampicillin the patient underwent surgery and a left nephrectomy was performed. Pathologic examination revealed diffuse extensive acute and subacute pyelonephritis with focal papillary necrosis, hydronephrosis, and UPJ stenosis. The patient recovered uneventfully.

Effects of stress management training and dietary changes in treating ischemic heart disease

To evaluate the short-term effects of an intervention that consists of stress management training and dietary changes in patients with ischemic heart disease (IHD), we compared the cardiovascular status of 23 patients who received this intervention with a randomized control group of 23 patient who did not. After 24 days, patients in the experimental group demonstrated a 44% mean increase in duration of exercise, a 55% mean increase in total work performed, somewhat improved left ventricular regional wall motion during peak exercise, and a net change in the left ventricular ejection fraction from rest to maximum exercise of +6.4%. Also, we measured a 20.5% mean decrease in plasma cholesterol levels and a 91.0% mean reduction in frequency of anginal episodes. In this selected sample, short-term improvements in cardiovascular status seem to result from these adjuncts to conventional treatments of IHD.