Misplacement of central venous pressure catheters and unilateral pulmonary edema.

Two instances of misplacement of a central venous pressure monitoring catheter into a pulmonary artery are presented. In one case, reported in detail, unilateral pulmonary edema developed during administration of 0.5N saline for the treatment of diabetic acidosis via the misplaced catheter, and it reverted following repositioning of the catheter in the superior vena caca. Experiments were carried out in dogs to explore possible causes of this phenomenon. The results of these experiments suggest that the release of vasoactive substances, stimulation of neural reflexes, or both are the pathophysiological mechanisms responsible for the development of the pulmonary edema.

Radioisotopic detection of osseius metastases. Evaluation of 99mTc polyphosphate and 99mTc pyrophosphate.

A total of 146 patients were investigated for the presence of osseous metastases with 99mTc polyphosphate or 99mTc pyrophosphate bone scans. Results of bone imaging were retrospectively compared to roentgenographic results surveying similar anatomic areas in 128 patients. This comparison revealed that roentgenographic interpretations were in error in 19% of the cases. Thirty-three patients had bone scans and roentgenograms that were in agreement and considered abnormal, but in more than one third of these cases the patients had multiple abnormalities that were shown by the bone scan but were not recognized roentgenographically. In consideration of the low toxicity, ready availability, economy, shortened procedure time, and low radiation dose associated with the use of these new bone-seeking agents, it is concluded that they are superior to roentgenograms and previously utilized radionuclides for early detection of osseous metastases.

Local colloid trapping in the liver in the inferior vena cava syndrome.

Local radioactive areas in the liver were observed as a result of superficial cavoportal shunting of radiocolloids in two patients with the inferior vena cava syndrome. In one patient a paraumbilical and/or a recanalized umbilical vein was apparently involved in the hepatopetal shunting. In the other patient a superficial anastomosis other than the paraumbilical vein shunted colloid to the liver. Relatively discrete areas of increased radioactivity, single or multiple, were seen in the left lobe. Virtually all reported instances of hepatopetal shunting of radioparticles in a superior or an inferior vena cava syndrome have demonstrated similar findings. Various hepatopetal collateral pathways in infrarenal caval obstruction are considered, and factors that could affect liver scan findings in the infrarenal obstruction are discussed.

Xenon-133 retention in hepatic steatosis-correlation with liver biopsy in 45 patients: concise communication.

This study presents the results of comparison of hepatic fat content with hepatic xenon retention in 45 patients. The degree of hepatic Xe-133 retention was measured during pulmonary ventilation studies. The amount of hepatic steatosis was graded 0 to 4+ on histologic liver sections obtained by needle or surgical biopsy. There was agreement between the amount of hepatic xenon retention determined scintigraphically and the degree of steatosis determined histologically. These results suggest that Xe-133 retention in the liver provides a simple means of evaluating fatty infiltration of the liver. The potential of this technique as a noninvasive means of investigating hepatic fatty infiltration is discussed.

Liver scanning and the intrahepatic gallbladder: Case report.

Hepatic focal defects identified with 99mTc-sulfur colloid imaging procedures are nonspecific. This report describes a case of an ectopic gallbladder localized by cholecystography and 131I-rose bengal studies in a patient with cirrhosis and suspected intrahepatic neoplasm.

Radionuclide venography and lung scanning: Concise communication.

In 102 patients suspected of pulmonary embolism, we have assessed the ability of a radionuclide (emission) venogram to complement the pulmonary perfusion scintigram in establishing a diagnosis. The efficacy was compared using decision analysis and Bayes's theorem. Two criteria for a positive test were compared: Criterion 1--the test is positive if the lung scan a) indicates a high probability of pulmonary embolus, or b) is abnormal but indeterminate for pulmonary embolus; Criterion 2--the test is positive a) if the lung scan indicates a high probability of pulmonary embolus, or b) if the emission venogram is positive in a patient with a lung scan considered abnormal but indeterminate for pulmonary embolus. The use of Criterion 2 decreased the sensitivity from 100% to 95% and increased the specificity from 74% to 93%. We conclude that a simultaneous emission venogram assists in improving the specificity, accuracy, and the predictive value of a standard pulmonary perfusion study in the diagnosis of pulmonary embolus.

Comparative evaluation of renal transplant rejection with radioiodinated fibrinogen 99mTc-sulfur collid, and 67Ga-citrate.

The diagnostic accuracy, ease, and technical feasibility of imaging with 131I-or 125 I-fibrinogen, 99mTc-sulfur colloid, and 67 Ga-citrate in renal transplant rejection are compared. Radiofibrinogen data resulted from literature review, radiocolloid data from 125 studies in 52 transplant patients, and gallium citrate data from 24 examinations in seven renal transplant patients performed simultaneously with the radiocolloid studied. Specificity of graft labeling during rejection appears to be similar with radiofibrinogen, 99mTc-sulfur colloid, and 67Ga-citrate. For routine clinical use 99mTc-sulfur colloid surpasses radiofibrinogen and radiogallium because of its better imaging qualities with a permissible radiation dose, leading to better separation of positive and negative results. The 99mTc-sulfur colloid accumulates in areas of intravascular fibrin thrombosis in acute and chronic rejecting renal transplants. Hence, the mechanisms for accumulation of 99mTc-sulfur colloid and labeled fibrinogen in rejecting transplants would seem to be similar. Such physiologic properties as rapid blood clearance and such physical properties as short physical half-life combine to produce reliable graft visualization with adequate definition, thus favoring 99mTc-sulfur colloid as the single agent of choice for clinical evaluation of renal transplant rejection at this time.

Numerical T1 computation from NMR intensity ratios.

Two-point measurement of tissue T1 from NMR intensity ratios consists of forming an a priori ratio function describing a T1 dependence of the ratio R(T1) and computing T1 from an observed ratio Q by numerically solving R(T1)-Q = 0 or an equivalent equation. Impact of R(T1) designs on the numerical computation and dependence of relative speeds of three numerical methods on desired computational precisions q and on other factors are examined. All three methods begin with computing a table of R(T1) entries in uniform T1 steps (delta T1). In two iterative methods, a step containing the T1 root is looked up, and the precise T1 location within the step is pinpointed to within a q value by either linear-interpolative (LI) or Newton-Raphson (NR) iteration. The third method simply consists of computing a large table of delta T1 = q for a mere "look-up" with no iterative search. All three methods require a monotonous R(T1) for uniformly effective computation over wide T1 ranges. Speeds of either iterative method for computing T1 images are expected to vary with delta T1 and q with unsharp speed maxima at delta T1 near 20, 6, and 2 ms for q = 10(-1), 10(-2), and 10(-3) ms, respectively. Either iterative method is suitable for both low- and high-precision computations, the LI method being generally faster. The simple look-up is the fastest of the three for T1 image computation to low precisions of q greater than or equal to 1 ms, is likely the slowest for that to q = 0.1 ms, and is impractical for that to q less than or equal to 0.01 ms.

Bone marrow 99m Tc sulfur colloid distribution and marrow cellularity.

The relationship between marrow distribution as imaged with 99mTc sulfur colloid and histologic estimate of bone marrow cellularity was examined in 101 patients. The patients were divided into three groups according to marrow cellularity: normocellular, hypercellular or hypocellular marrow. The marrow distribution of these patients was graded as extended, not extended or not visualized. A general association between marrow cellularity and marrow distribution was found. Seventy-seven per cent of patients with normocellular marrow had limitation of marrow within normal sites and a similar number of patients with reactive hypercellular marrow had marrow extension. On analysis of the patients that were exceptions to this generalization the following observations were made. In patients in whom the marrow is hypercellular and infiltrated with abnormal cells or tissue the marrow distribution may not be visualized with radiocolloid. Stimulation of hematopoiesis may result in marrow hypercellularity without marrow extension beyond the usual sites. Stimulation of one or more hematopoietic cell lines may result in marrow extension without marrow hypercellularity, suggesting an impairment of hematopoietic cell response. Peripheral marrow extension as observed with radiocolloid, therefore, is not simply a reflection of marrow hypercellularity but probably represents a response of the bone marrow stroma to situations in which one or more hematopoietic cell lines is stimulated.

Clinical estimation of infarct size by 201thallium perfusion scintigraphy and by creatine kinase-MB in early myocardial infarction.

201Thallium (201Tl) perfusion scintigraphy was performed in 22 patients with first acute transmural myocardial infarction within the initial 12 h after onset of symptoms. The size of the abnormally perfused area on 201Tl images was estimated by visual analysis and by a computer-assisted technique. 201Tl values for infarct size were compared to a biochemical estimate of infarct size using the cardiac specific esoenzyme creatine kinase-MB (CK-MB) and total creatine kinase (CK). Estimates of myocardial damage obtained from the visual and computer-assisted analysis of the 201Tl images showed a statistically significant correlation with the enzymatic estimates of infarct size. These results suggest that quantitative evaluation of 201Tl image defects may provide useful information regarding the degree of myocardial damage in the very early stages of acute infarction before biochemical estimates of infarct size are available, and that sequential imaging with 201Tl might provide an independent method of monitoring evolutionary changes in myocardial damage.