A comparative study of renal scintigraphy and clearance with technetium-99m-MAG3 and iodine-123-hippurate in patients with renal disorders.

The aim of this study was to compare kit prepared technetium-99m-mercaptoacetyltriglycine (99mTc-MAG3) with our routine radiopharmaceutical, iodine-123-hippurate our routine radiopharmaceutical, iodine-123-hippurate ([123I]OIH) for renal dynamic scintigraphy. Seventeen patients with different nephrologic disorders or hypertension were first studied with OIH and then reinvestigated with MAG3 2-8 days later. Renal MAG3 gamma camera images were almost identical with those of OIH except for higher (p less than 0.01) liver-to-background ratios at 20 min postinjection, irrespective of kidney function. Urinary peristalsis was visible longer and more clearly in the MAG3 studies. MAG3 and OIH renograms showed identical relative kidney uptake (r = 0.99), but elimination of MAG3 from the kidneys was slower (p less than 0.01). The plasma clearance of MAG3 was lower than that of OIH, but correlated (r = 0.92) significantly. The plasma distribution volume and content in blood cells was lower (p less than 0.01), but the binding of MAG3 to plasma proteins was higher, 90%, as compared with 74% for OIH, p less than 0.01. Urinary excretion expressed as a percent of the given dose 60 min after injection was the same for the two substances. Thus, there are some significant differences in the renal handling, plasma distribution, and cell penetration between MAG3 and [123I]OIH. MAG3, however, seems to have particular qualifications as a radionuclide for dynamic renal scintigraphy, especially in patients who require acute investigations or in those with low renal function.

Evaluation in femoral neck fracture scintimetry: modes of region of interest selection and influence on results.

Different sized ROIs within the femoral head and different modes of calculation were used in [99mTc]MDP scintimetry after femoral neck fracture. In preoperative scintimetry, correction for increased trochanteric uptake gave the best discrimination, whereas in postoperative scintimetry the direct ratio fractured/intact femoral head was superior. The change in ROI size had little influence.

Regional cerebral blood flow scintigraphy in tick-borne encephalitis and other aseptic meningoencephalitis.

UNLABELLED: In a prospective study, regional cerebral blood flow (rCBF) was studied in patients with aseptic meningoencephalitis at 6 wk and 1 yr after onset of disease. METHODS: Patients with tick-borne encephalitis ([TBE] n = 73) and meningoencephalitis of other etiology ([non-TBE] n = 56) were investigated with rCBF-scintigraphy (SPECT). SPECT images in the acute phase of disease and at long-term follow-up were analyzed for blood-flow disturbances and their localization in the central nervous system and were correlated to clinical course and outcome. RESULTS: Decreased rCBF was seen in 50% of patients after 6 wk (TBE 49%, non-TBE 50%) and in 46% (TBE 47%, non-TBE 46%) after 1 yr. The decrease in rCBF was moderate in 18% and 11% at 6 wk and in 8% and 9% at the 1-yr follow-up of TBE and non-TBE patients, respectively. Reduced rCBF was significantly more common among patients with encephalitis than among those with meningitis, and more common in males. The distribution of cerebral flow changes was predominantly patchy or multifocal. At long-term follow-up, improvement in rCBF was seen in 28 of 109 patients (26%), but worsening of decreased rCBF was demonstrated in 19 of 109 (17%). In TBE patients, remaining neurological symptoms at 6 wk of disease were associated with worsening of decreased rCBF at the 1-yr follow-up. CONCLUSION: With SPECT, rCBF changes, mostly slight and patchy or multifocal, were detected in patients with aseptic meningoencephalitis. Decreased rCBF was more frequent in patients with moderate-to-severe encephalitis, although the clinical use in predicting long-term outcomes in aseptic meningoencephalitis (e.g., TBE) seems limited.

Bile reflux to the stomach and gastritis before and after cholecystectomy.

Thirty-four patients with gallstone disease were examined with cholescintigraphy and gastroscopy before and after cholecystectomy. Sixteen patients had a functioning and 23 a non-functioning gallbladder at cholescintigraphy. At scintigraphy 99Tcm-activity was found over the gastric fundus in 28% before and in 22% after cholecystectomy and there was no difference between the groups with and without a functioning gallbladder regarding bile reflux. Before cholecystectomy bile-stained contents in the stomach was significantly more often found among those with a non-functioning gallbladder (87%) than in those with a functioning gallbladder (44%). After cholecystectomy the number of patients with bile-stained contents in the stomach was high in both groups (92% and 82% respectively). No correlation could be found between the two methods to detect bile in the stomach. Before cholecystectomy patients with a functioning gallbladder had inflammatory changes in the antral as well as the fundic mucosa in 31%. Patients with a nonfunctioning gallbladder had inflammatory changes in the antral mucosa in 47% and in the fundic mucosa in 56%. These differences were however not statistically significant. No correlation could be found between bile-stained contents in the stomach and chronic gastritis or scintigraphically detected bile in the stomach and chronic gastritis. The degree and distribution of chronic gastritis was virtually unchanged one year after cholecystectomy.

Repeated exercise and redistribution thallium-201 scintigrams in patients with myocardial infarction treated with timolol or placebo.

Repeat exercise thallium-201 scintigrams were performed 2 weeks, 3 months, and 6 months in 27 patients following their first myocardial infarction. All patients were treated with timolol or matching placebo, administered intravenously starting within 5 hours of onset of chest pain. The extent of transient perfusion defects in 15 timolol-treated patients increased significantly between 2 weeks and 3 months compared to a decrease in 12 placebo-treated patients (p less than 0.05). Between 3 and 6 months the extent of transient defects did not change in the two groups, and there was no difference between the groups. The extent of permanent defects was not significantly different between the timolol- and placebo-treated patients on any occasion. However, patients in the timolol group had a decrease in permanent defects with time in contrast to patients in the placebo group (p less than 0.05). Thus, early intervention with timolol in the acute phase of myocardial infarction may have consequences for the postinfarction phase, as reflected in repeat thallium-201 scintigrams.

Comparison of adenosine and exercise stress test for quantitative perfusion imaging in patients on beta-blocker therapy.

UNLABELLED: Beta-blocker therapy is used to decrease myocardial ischemia during exercise but may cause suboptimal diagnostic performance in exercise stress testing. The aim of the present study was to compare results of quantitative technetium-99-sestamibi single photon emission tomography (SPECT), following exercise stress test or pharmacological stress test with adenosine. We chose adenosine as comparison, since betablockers may not interfere with adenosine induced vasodilatation and therefore possibly may not interfere with its diagnostic performance. Sixteen patients with angiographically documented coronary disease (5 single-vessel, 6 two-vessel and 5 three-vessel disease), who were chronically treated with beta-blockers, performed SPECT imaging at rest, following bicycle exercise and following adenosine infusion in random order. The SPECT data were analyzed visually and quantitatively, using dedicated computer software (CEqual). According to both visual and quantitative SPECT analysis, adenosine was superior to show reversibility. Higher reversibility extent (50 +/- 15 vs. 26 +/- 12 pixels, p < 0.01) and more intense reversibility severity (110 +/- 29 vs. 49 +/- 23 sum of SDs, p < 0.05) were observed during adenosine than exercise. CONCLUSIONS: Less myocardial perfusion abnormalities during exercise than during adenosine stress in patients treated with beta-blockers may indicate less ischemia but also an impaired diagnostic performance. Thus adenosine stress test should be preferred to optimize the diagnostic sensitivity in patients during beta-blocker treatment.

Does diffuse coronary atherosclerosis affect the relation between coronary stenoses and uptake of thallium-201 after exercise?

It has been proposed that diffuse coronary atherosclerosis influences the myocardial perfusion. We performed a study of 94 young men with previous myocardial infarction in order to find out whether the presence and extent of diffuse coronary atherosclerosis affected the relation between maximal stenosis and myocardial perfusion in areas remote from the infarction. The patients were examined by planar-imaging thallium-201 scintigraphy, following exercise, and coronary angiography within 6 months after myocardial infarction. The maximal distinct stenosis and diffuse coronary atherosclerosis, comprising both plaque size and extent, were semiquantitatively assessed. The correlation coefficients between maximal stenosis within the LAD, RCA, and LCX vascular territories and the corresponding initial uptake of thallium were 0.52 (P = 0.0001), 0.30 (P = 0.04), and 0.46 (P = 0.02), respectively. No change of the correlations was found, except for a slight increase of the r-value from 0.30 to 0.37 in regions corresponding to RCA, after controlling for the diffuse atherosclerosis score in a multiple stepwise regression analysis. These findings indicate no impact of diffuse coronary atherosclerosis on regional myocardial perfusion in areas remote from the infarction.

Coronary angiographic changes during 2 years after myocardial infarction largely undetected by repeated tomographic thallium-201 scintigraphy and not reflected by clinical symptoms.

Repeated coronary angiographies and single photon emission computed tomographies (SPECT) were performed at 9 and 33 months after myocardial infarction (MI) in 47 young men. Coronary lesions were classified in eight grades with respect to the reduction of the luminal diameter. The progression and regression of two steps or more in lesions of grade 2 or more, the recanalization of coronary thrombosis and an increase in collaterals were recorded. Patients were divided into three groups with regard to (A) deterioration, (B) improvement and (C) no changes in the three major coronary regions, respectively. Overall, 23 patients (49%) showed changes between the first and the second investigation. A simplified method using summarized short-axis slices for evaluation of the thallium-201 SPECT showed a significant difference in change of regional myocardial uptake of thallium-201 between groups A and B (P = 0.047) but not between the groups A and C, in lateral myocardial regions. No significant differences were found between any of the groups in respect of the anterior or inferior myocardial regions. These findings were not explained by changes in clinical status, maximum heart rate or workload, or by changes in medication. Our results suggest that substantial changes in coronary morphology can take place during the 2 years following MI without consistent changes in clinical symptoms or regional myocardial perfusion.