Identification of hypometabolic areas in the brain using brain imaging and hyperbaric oxygen.

Current neurologic assessments consider idling neurons and ischemic penumbras to be metabolically lethargic and electrically nonfunctional or nonviable. Diagnosis, prognosis, and therapeutics of central nervous system dysfunctions require differentiation between viable and nonviable neurons. It is necessary to develop and document efficacious and safe techniques for reactivating idling neurons. The authors present a case study of a near drowning 12 years earlier. Areas of cortical hypometabolism were identified by using SPECT imaging in conjunction with hyperbaric oxygen therapy (HBOT). Delayed imaging after HBOT (1 hour, 1.5 atm abs) suggested viable but metabolically lethargic neurons. After HBOT (80 1-hour treatments, monoplace chamber, 1.5 atm abs), marked improvements in cognitive and motor functioning were demonstrated. The data support the hypothesis that idling neurons and ischemic penumbras, when given sufficient oxygen, are capable of reactivation. Thus, changes in tracer distribution after a single exposure to HBOT may be a good prognostic indicator of viable neurons. HBOT may be valuable not only in recovery from anoxic encephalopathy but also from other traumatic and nontraumatic dysfunctions of the central nervous system, including stroke. HBOT in conjunction with physical and rehabilitative therapy may help reactivated idling neurons to remain permanently active.

Enhanced diagnosis of hand and wrist disorders by triple phase radionuclide bone imaging.

Triple phase radionuclide bone imaging (TPI), a diagnostic study, consists of a blood flow evaluation by means of an intravenous bolus injection of radionuclide tracer and rapid sequential images which show the arterial pattern; an immediate static image reflecting the pooling of activity in the soft tissues; and delayed static images taken about one hour later which reflect bone localization of the radiotracer. TPI is not specific for a particular condition, but it will confirm or rule out the presence of disease.

[67Ga]citrate scintiscanning in active inflammatory bowel disease.

Twenty-five hospitalized patients were studied prospectively with [67Ga]citrate (GA) abdominal scintillation scanning in an attempt to define its role in the evaluation of patients with active inflammatory bowel disease (IBD). There were nine patients with ulcerative colitis (UC), seven with Crohn's disease (CD), and nine controls. In four patients, two with UC and two with CD, a tissue/plasma radioactivity ratio was obtained and compared to normals. All the UC patients had positive GA scans and only one of seven of the CD patients had a positive scan. There were no false positive scans. Scans performed after a 3- or 5-day delay were more accurate than 6-hr scans alone. Well-delineated colinic radioactivity 6 hr after injection which persists for 3 to 5 days indicates the presence of UC in patients with IBD, while a negative scan is more consistent with active CD. Colonic uptake at 6 hr which clears by 48 or 72 hr is not indicative of UC. This procedure aided in following the course of UC, delineating the extent of disease, and in differentiating active CD from an intraabdominal abscess. Tissues from UC patients had increased tissue/plasma ratioactivity ratios while tissues from CD patients had normal or decreased ratios which were consistent with the imaging data.

Computerized tomography, diagnostic ultrasound, and radionuclide scanning. Comparison of efficacy in diagnosis of pancreatic carcinoma.

Forty-six patients, including 33 with proved pancreatic carcinoma, were studied with computerized tomography (CT), ultrasound (US), and radionuclide (RN) scanning. The results of each scanning procedure were compared with the surgical and clinical findings. The detection rate was 82% for CT, and 92% with US. A mass is the most important finding in the diagnosis of pancreatic carcinoma. Measurements of the pancreas with CT and US were similar, with visualization of all parts of the pancreas routinely better with CT scans. Radionuclide scans were abnormal in 96% of the patients with pancreatic carcinoma as well as in 75% of patients without pancreatic disease. A rational approach to examination of a patient with suspected pancreatic carcinoma should begin with US scan with available, because the detection rate with this method is equal to that with CT and its cost per procedure and for equipment is substantially less.

A new dual-probe system for the rapid bedside assessment of left ventricular function.

A mobile dual-probe system has been developed for the rapid bedside measurement of left ventricular ejection fraction (LVEF) from the beat-to-beat count rate variations that occur during the transit of a single radionuclide bolus through the left ventricle (LV). Cardiac output, pulmonary blood volume, and left ventricular end-diastolic volume can also be calculated. The dual-probe system incorporates a central collimated probe for monitoring activity in the LV surrounded by an annular detector collimated in such a manner as to provide simultaneous real-time monitoring of the LV background activity. The LVEFs obtained from this system correlated well with LVEFs derived from conventional single-plane contrast angiography (r=0.90) in a series of 33 patients with coronary artery disease. Positioning the dual probe over the midpoint of the LV is accomplished with standard M-mode ultrasound. Since the method is noninvasive and sensitive to volume changes in the LV, the dual probe is particularly useful for monitoring seriously ill patients as well as those with segmental wall-motion abnormalities.

Applications of diagnostic ultrasound and radionuclides to cardiovascular diagnosis. Part I. Acquired cardiovascular disease in the adult.

Noninvasive methods have become an important part of the diagnostic process for evaluation of cardiovascular anatomy and function in adults and in the young. Because there is a multiplicity of noninvasive methods presently available, in some cases with overlapping capabilities, there has been some confusion as to which constitutes the method of choice in a given clinical circumstance. The reviews that follow outline some of the practical strengths and limitations of two methods (echocardiography and radionuclide cardiography), hopefully thereby providing some rationale for choosing the more appropriate technique in the approach to specific clinical problems. We have found that the information available from radionuclide and from ultrasound studies frequently is complementary and that the most optimal diagnostic results often are obtained when they are combined. Since advances in technique and improvements in instrumentation are occurring continually in both of these areas, we have tried to provide only an overview. Further investigations and clinical experience will help to define the specificity, sensitivity, and capabilities of these methods in terms of present and future applications.

Applications of diagnostic ultrasound and radionuclides to cardiovascular diagnosis. Part II. Cardiovascular disease in the young.

Echocardiography (ECHO) and radionuclide cardiography have had a significant impact on pediatric cardiology because they have proved to be sensitive enough to permit early diagnosis of many forms of heart disease and in some cases to estimate its severity and to provide information concerning ventricular performance. An overview of the anatomic and functional information that can be obtained from these two methods will be presented first, followed by details concerning the indications for their use and their relative clinical value in various acquired and congenital heart diseases. We have stressed particularly those facets of pediatric cardiac disease that differ most from those in the adult.