Evaluation of technetium-99m-ethylenedicysteine in renal disorders and determination of extraction ratio.

UNLABELLED: This article evaluates the clinical usefulness of 99mTc-ethylenedicysteine (EC) in patients with various renal disorders. In addition, extraction ratios of 99mTc-EC in five volunteers were also determined. METHODS: Twenty patients were intravenously injected with 200 MBq 99mTc-EC and 2.5 MBq [131I]orthoiodohippurate (OIH) simultaneously and 11 blood samples were withdrawn within 60 min. Plasma clearance was determined on the basis of a two-compartment model. Imaging was performed in the posterior projection by acquiring three sets of images. Extraction ratios were determined from the blood samples obtained from the renal vein and abdominal aorta. RESULTS: Renal clearance of 99mTc-EC was significantly lower than that of OIH (p = 0.0003) with good correlation (r = 0.93). Volume distributions of 99mTc-EC and OIH were 26584 +/- 10807 ml/1.73 m2 and 23148 +/- 7602 ml/1.73 m2, respectively (p = 0.047). The clearance half-lives of 99mTc-EC and OIH were 98 +/- 54 min and 74 +/- 54 min, respectively (p = 0.049). Protein binding of 99mTc-EC (33 +/- 3.2%) was significantly less than that of OIH (62 +/- 2.8%) (p < 0.0001). Red blood cell binding of 99mTc-EC was almost negligible (5.7 +/- 4.3%). Similar extraction ratios were obtained from blood (0.68 +/- 0.08) and plasma (0.70 +/- 0.07) (p = 0.062). The 60-min excretion fractions were similar for 99mTc-EC and OIH, with values of 50% +/- 20% and 51% +/- 19%, respectively (p = 0.9). CONCLUSION: Technetium-99m-EC is a suitable radiopharmaceutical for routine renal dynamic studies. Although the biological behavior of 99mTc-EC seems to be different from that of OIH, their clearances demonstrate high correlation. Technetium-99m-EC provides excellent quality images and has high potential in the evaluation of quantitative renal functions.

A comparison of Tl-201 stress-reinjection-prone SPECT and Tc-99m-sestamibi gated SPECT in the differentiation of inferior wall defects from artifacts.

The frequency of false positive results obtained from the inferior myocardial region using single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy is significantly higher than that obtained from other regions. Several methods, such as prone-position imaging, have been proposed to overcome this diagnostic problem. The aim of the present study was to compare the results of Tc-99m-sestamibi gated SPECT and Tl-201 prone SPECT in the differentiation of inferior wall artifacts from true defects. For this purpose, 38 subjects, whose coronary anatomies were documented on angiography, underwent same-day stress-rest Tc-99m-sestamibi gated SPECT and Tl-201 stress-reinjection-prone (whose standard supine images demonstrated fixed defects on the inferior wall) SPECT. Gated SPECT was performed by 8 frames per cycle acquisition over a 180 degree rotation on 30 projections. Four gated SPECT slices were obtained on mid-ventricular vertical long axis, horizontal long axis and apical and basal short axis planes, and displayed in cine-format. Both Tl-201 prone imaging and Tc-99m-sestamibi gated analysis increased the specificity of inferior wall disease detection remarkably from 54% to 85% and 46% to 82%, respectively (P<0.05). The difference between diagnostic accuracies was not significant (80% and 82%, respectively) (P > 0.05). The positive predictive values for true defects were 96% for Tl-201 prone imaging and 94% for Tc-99m-sestamibi gated imaging. Based on segmental analysis, the two modalities showed fair agreement (kappa = 0.44 for standard supine protocols, kappa = 0.46 for Tl-201 prone and Tc-99m-sestamibi gated SPECT). It can be concluded that Tc-99m-sestamibi gated SPECT, requiring only two-step acquisition, may potentially increase the test specificity for coronary artery disease (CAD) of the inferior wall as well as does Tl-201 stress-reinjection-prone SPECT. By giving functional information, it seems the most practical method in daily use for supplying the most extensive information about patients with suspected or known CAD.

Distinguishing between acute appendicitis and appendiceal mucocele: is this possible preoperatively?

PURPOSE: Mucocele of the appendix is an infrequent event, characterized by a cystic dilatation of the lumen. It is often diagnosed clinically from signs and symptoms of acute appendicitis or, if it is asymptomatic, as an incidental finding during ultrasonography, computed tomography, or laparotomy. METHODS: We evaluated the histological data of patients who were believed to have mucocele of the appendix. These patients (n = 23) were compared with sex- and age-matched control subjects (n = 79) with appendicitis. RESULTS: The main reason for emergency surgery was lower right abdominal pain in 15 patients, and intestinal obstruction in three. Univariate analysis using sonography demonstrated that the larger appendiceal outer diameter was positively correlated with the diagnosis of appendiceal mucocele (p = 0.001) and the mean white blood cell count was negatively correlated (p = 0.023). In urine analysis, 41.7 % of the mucocele patients and 10 % of the appendicitis patients had microscopic hematuria, respectively (p = 0.019). An outer diameter of 10 mm or more was predictive of appendiceal mucocele diagnosis, with a sensitivity of 76.5 %, specificity of 81 %, positive predictive value of 76.5 %, and negative predictive value of 94.12 %. The overall diagnostic accuracy was 80.2 %. One point was given for the presence of each of these factors to develop a new score. The resulting area under the receiver operator characteristic curve was 0.855 (95 % CI 0.741-0.969) for the score. The histological examination of the specimens revealed mucocele in 15 cases, mucinous cystadenoma in seven cases and mucinous cystadenocarcinoma in one case. Twenty patients underwent appendectomy, and three patients were treated with right colectomy. CONCLUSIONS: A threshold 10-mm diameter of the appendix under compression is a useful preoperative measurement for differentiating between appendiceal mucocele and acute appendicitis. Microhematuria is simple test that can provide a significant role in supporting the clinical diagnosis of appendiceal mucocele in the emergency department.

Factor VII levels in patients undergoing coronary angiography: factor VII and coronary artery disease.

BACKGROUND: Factor VII (F VII) has been widely investigated as a risk factor for coronary atherosclerosis, however there is still debate about its role in the progression of coronary artery disease (CAD). In this study F VII levels were measured in patients with angiographically proven CAD and its relation with disease severity, coronary events and with other risk factors of coronary atherosclerosis were examined. METHODS: Consecutive patients referred to coronary angiography were divided in three groups: 1. CAD group--those with a significant lesion in one or more coronary arteries (n = 155), 2. High-risk group--patients with normal coronary arteries and with two or more risk factors (n = 54), 3. Controls--patients with normal coronary arteries and with no or one risk factor (n = 90). CAD group was also studied according to the number of vessels involved and to the history of coronary events. RESULTS: Mean F VII levels were not different between the three groups of patients. In CAD group, F VII increased parallel to the number of vessels involved (one vessel disease: 85 +/- 20%, two vessel disease: 92 +/- 23%, three vessel disease: 105 +/- 23%). Patients with a history of coronary events had significantly higher F VII levels than those without such a history (96 +/- 25% versus 89 +/- 22% respectively, P = 0.02). However, logistic regression analysis revealed no significant relation between F VII and either the presence of CAD or coronary events. CONCLUSIONS: F VII levels increase in patients with previous coronary events, but it is not an independent risk factor for the progression or for the severity of CAD.