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A 3-year-old boy with unilateral absence of the right pulmonary artery had a lung scan that demonstrated 46% of total ventilation on that side. This had fallen to 39% by 2 years later, and at 11 years after the first study the value was 30%. Ventilation lung imaging may be useful in demonstrating the degree of ventilatory dysfunction in a lung compromised by absence of the pulmonary artery. Possible causes of the pulmonary damage are discussed.

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Ventilation-perfusion lung scans are routinely performed using Tc-99m labeled MAA particles administered intravenously which are subsequently trapped in the pulmonary artery capillary bed. In the presence of a right-to-left shunt, activity may be seen in the systemic circulation. Right-to-left shunts may be worsened by inducing hypoxemia which causes pulmonary artery constriction, and also by increasing venous return to the heart. In this case, the authors used various maneuvers to increase right-to-left shunting and thereby demonstrated the presence of fixed pulmonary hypertension. These findings suggested that the patient's dyspnea on exertion was not primarily because of left ventricular dysfunction, and proposed coronary bypass surgery was deferred for medical management.

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Transient regional osteoporosis of the ankle and foot is an uncommon clinical entity characterized by local tenderness over the involved area. Plain radiographs demonstrate osteopenia of the involved bone and technetium diphosphonate bone imaging shows increased tracer uptake at the same location. This disorder is benign and self-limiting, and treatment is conservative.

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A 74-year-old woman underwent two operations to correct an aortoduodenal fistula and to have an axillofemoral bypass graft inserted; these required temporary vascular occlusion. Her hepatic function test results began deteriorating. Initial and follow-up Tc-99m sulfur colloid studies revealed activity in the kidneys, consistent with disseminated intravascular coagulation. There was significant radiocolloid in the bone marrow and lungs, suggesting severe hepatic dysfunction. The spleen was not demonstrable on dynamic images or static views. In addition, there was a significant lateral hepatic defect, with a "lung overlap." The splenic lack of function and the hepatic lesion were due to necrosis (demonstrable on CT imaging), likely related to the prior vascular clamping.

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Two cases of splenic uptake of Tc-99m MDP are presented, in which there was preserved reticuloendothelial activity (Tc-99m sulfur colloid accumulation). In addition to the literature data, data from these cases were used to show the disassociation of uptake of bone agents and radiocolloid in the spleen. Prior reports, in which both agents concentrated in the spleen, were tabulated. An updated gamut on splenic accumulation of Tc-99m MDP or analogues was given.

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Immunosuppressed febrile organ transplant patients present a diagnostic and therapeutic dilemma since symptomatology is often altered by immunosuppression, which also masks the location of infection. Fifty 111indium leukocyte ( 111In WBC) scans were performed to determine their usefulness in the organ transplant patient. The results were compared with computerized tomography (CT) and gallium 67-citrate (Ga) scanning. Eleven patients received both 111In WBC and Ga scans; 22 received both 111In WBC and CT scans. Ten 111In WBC scans had subtraction of 99m Tc sulfur or albumin colloid for liver evaluation and four 111In WBC scans had subtraction of 99m Tc DMSA for kidney evaluation. The overall sensitivity and specificity for 111In WBC scans was 90% and 90%, respectively. Lung uptake was sensitive (89%) and specific (97%) for pulmonary infections, including bacterial, fungal and cytomegalovirus pneumonias. Renal graft uptake occurred in 15 cases (41%), all except 2 being due to rejection, pyelonephritis, urinary tract infections, or cytomegalovirus infections. Pyelonephritis and renal abscesses were diagnosed in 3 cases with 99m Tc DMSA subtraction. Perihepatic abscesses (2), and infected liver cysts (4) were diagnosed with 99m Tc sulfur or albumin colloid subtraction. There were five false-negative CT scans and three false-negative Ga scans. Therefore, when compared with 111In: sensitivity = 88% vs 64% (CT), specificity = 80% vs 86% (CT); and sensitivity = 111In 90% vs 67% (Ga), specificity = 100% for both 111In WBC and Ga scans.(ABSTRACT TRUNCATED AT 250 WORDS)

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Bone scans in two patients with Gaucher's disease were reported as consistent with Gaucher's-associated osseous crises. A bone-radiogallium subtraction study was also initially negative in each individual (although it later became positive in one). At surgery both patients were seen to have osteomyelitis. These two cases point out the difficulty in attempting to diagnose osteomyelitis in the presence of Gaucher's bone disease. A possible role for MRI in such instances was mentioned. Also noted was clinical reluctance to accept a diagnosis of osteomyelitis (positive bone-radiogallium subtraction study) in an afebrile Gaucher's patient.

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During a cardiac blood pool study (Tc-99m erythrocytes), there was an apparent "cold" area in the left lobe of the liver. At one hour, the prior void appeared to have filled in, suggesting an intrahepatic hemangioma. However, the changing pattern of radioactivity, and its shape, indicated that this actually represented Tc-99m pertechnetate in the gastric wall and stomach cavity. In a second case, the interval between intravenous injection of stannous pyrophosphate and Tc-99m pertechnetate was prolonged. Changing activity, again in the gastric wall and cavity, obscured part of the liver. This cleared with time, allowing hepatic evaluation. Thus, gastric pertechnetate can contribute to blood pool images of the heart or liver and multiple images may be needed to separate this component from nearby tissues.

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We retrospectively investigated the relationship between left ventricular ejection fraction (EF) and end diastolic cross sectional area (DCS), by means of gated cardiac blood pool studies, in 62 individuals (68 studies) who were of age 85 y or older. In these "oldest old", a plot of log ejection fraction as a function of log cross sectional area revealed good correlation (r = 0.66). The graph demonstrated the increase in heart size with a falling ejection fraction. Of the "oldest old", 38% had EF values at or above 55%. By comparison, in a group of 100 patients of ages 55-75 y, 32% had EF values of or above 55%. In the "oldest old" 13/68 (19%) had "hyperdynamic" EF values over 65%; in the 55-75 y old group, this value was 16%. The log-log plot was divided into four quadrants by two lines (one at a DCS of 26 cm2 and the other at EF of 55%). Possible prognostic significance of each of these four categories will have to be determined by following the patients and sorting out the contributions of such factors as hypertension, coronary artery disease and medications.

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To examine whether the results and interpretation of gallium-67 citrate imaging may be adversely influenced by factors present in compromised patients, we reviewed our 1-year experience in 69 patients in intensive care units, renal transplants, and those on hemodialysis. Our results indicate that it is an inappropriate diagnostic procedure for acute pancreatitis since seven of nine had false-negative results. Using loglinear modeling and chi-square analysis we found that treatment with antiinflammatory steroids, severe liver disease, end-stage renal disease, and renal transplantation with immunosuppressive therapy did not interfere with gallium-67 uptake. Increased rate of true-negative results in patients with end-stage renal disease was due to a greater and earlier use of the test in the febrile transplant patient and in hemodialysis patients with infections not amenable to diagnosis with gallium-67 scan (transient bacteremia and bacteriuria). We conclude that gallium-67 imaging is a useful diagnostic tool that, with the exception of acute pancreatitis, has very few false-negative results.

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Analyses of procedure utilization are of importance if accurate projections are to be made of local and national needs as the population ages. Nuclear Medicine records of a general hospital were analyzed for 1986, to determine utilization patterns in the oldest old (age 85 years and greater) as compared with younger patients. The most elderly comprised 1.3% of the population of this state, but "consumed" 3.9% of the studies carried out in Nuclear Medicine (or a rate 3 times greater than expected). The average number of procedures/patient during the year was 1.56 in the oldest old vs 1.57 in younger individuals. The sex ratio of procedure utilization was 65% female (slightly lower than state wide national estimates of the female portion of the population). A far lower percentage of studies were performed as outpatients in the oldest old (12.2%) than in the younger population (44.9%); contributing factors were discussed. Of the procedures, several had the same percentage utilization in the oldest old and younger groups (gated cardiac blood pool, liver plus hepatobiliary, and radiogallium imaging). Bone scans were slightly less common in the very elderly. However, thyroid studies and radiothallium cardiac imaging were performed significantly less frequently in the more elderly. Procedures carried out more frequently in the very elderly were gastrointestinal bleeding examinations and lung imaging. Possible reasons for this were pointed out.

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A 64-year-old woman was febrile and had pain near the right hip. Blood cultures grew beta hemolytic streptococci. A bone scan showed reduced activity in the right femoral head and neck compared with the left femoral head and neck. She was treated with intravenous antibiotics and surgical decompression of a tense and bulging right hip joint. Five days later, a repeat bone scan revealed much of the femoral head activity to have returned. By day 20 after the initial bone image, there was intense activity throughout the femoral head and neck. Prompt relief of a distended hip joint can result in reperfusion of the femoral head and neck.

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