[en] Objective: To evaluate the relationship between deep vein thrombosis (DVT) and pulmonary embolism (PE) and the origin of PE. Methods: Fifty normal people and 200 patients with highly suspected PE and DVT of lower extremities underwent pulmonary perfusion/ventilation (P/V) imaging with ⁹⁹Tc^m-macroaggregated albumin (MAA) and ⁹⁹Tc^m-glucose phosphate (GP), 15 patients among them also underwent pulmonary artery angiography. Results: Fifty normal people gave normal images of P/V. Among 200 patients, 175 were with multiple PE, 25 were normal; among PE patients, 128 were with lower extremity venous disorders (73.14%), 25 cases without PE were all with extremity venous disorders; among 153 with lower extremity venous diseases, 128 were with PE (83.66%); 119 of them had DVT, 101 cases' PEs originated from iliofemoral vein thrombosis (84.87%). Conclusion: It is effective to diagnosis PE and its origin with combinative use of pulmonary perfusion/ventilation imaging and lower extremity vein imaging

[en] Objective: Pulmonary ventilation/perfusion (V/Q) imaging was used in the diagnosis of atypical subsegmental pulmonary embolism(PE) and monitoring the response to anti-coagulation. Methods: A total of 141 patients (58 men, 83 women, 40-83 years) underwent ⁹⁹Tc^m-MAA and ⁹⁹Tc^m-Technegas pulmonary V/Q imaging, and then underwent pulmonary perfusion imaging after 1-24 months oral anticoagulative therapy. Fourteen cases had lower limbs venous lesions, 45 diabetes mellitus or hyperlipaemia, and 63 the history of invasive diagnosis or therapy management recently. Pre- and post-anticoagulation images were compared and combined with clinical information and other imaging modalities to assess the subsegmental PE. Results: All pulmonary perfusion images showed defects in different sizes with normal pulmonary ventilation images. After therapy, the radioactive uptake and distribution in both lungs improved in 118/141 (83.69%) cases. The post-treatment scans were judged normal in 35 patients, obviously improved in 49, mildly improved in 34. Conclusion: Pulmonary V/Q imaging provided accurate information in both diagnosis and post-therapy monitoring of atypical subsegmental PE. (authors)

[en] Objective: To evaluate ¹⁸F-fluorodeoxyglucose (FDG) PET/CT in the rabbit model of vulnerable plaques by correlation with ⁹⁹Tc^m-Arg-Gly-Asp (RGD) SPECT/CT imaging, lipid levels, pathological and immunoh1stochemical results. Methods: Sixteen male New Zealand white rabbits were randomly divided into normal diet group (group A, n = 4), stable plaque group (group B, n = 4) and vulnerable plaque group (group C, n = 8) using completely random grouping method. The animals were given abdominal aorta sham operation (groups A and B) or balloon injury of the abdominal aorta (group C) 2 weeks after feeding. Animals were injected with ¹⁸F-FDG and ⁹⁹Tc^m-RGD respectively at the end of 4, 8 and 12 weeks. PET/CT was performed at 1, 2 and 3 h post-injection. SPECT/CT was performed at 30 min post-injection. One rabbit was sacrificed at the end of 4 and 8 weeks after imaging studies, respectively. The others were sacrificed at the end of 12 weeks after imaging studies. All abdominal aortas were harvested. Pathology and immunocytochemistry analysis were performed. The data were analyzed by one-way analysis of variance and Pearson correlation analysis. Results: There was no uptake in any group at 4th week and no uptake in group A or group B at 8th week. There was mild uptake in group B at 12th week and group C at 8th week. There was intense uptake in group C at 12th week, whereas both mean standardized uptake value (SUV_mean) and maximum standardized uptake value (SUV_max) were significantly higher than the other two groups (F values: 7.952, 14.279, both P < 0.05). In group C, SUV_max (0.43 ± 0.08, 0.68 ± 0.06, 1.74 ± 0.63) and SUV (0.37 ± 0.03, 0.56 ± 0.03, 1.26 + 0.23) had significant difference at 3 h post-injection for imaging at 4th, 8th and 12th week (F values: 10.939, 39.747, both P < 0.05). At 12th week, there was a strong correlation between the uptake of ¹⁸F-FDG and target/non-target (T/NT) ratio of ⁹⁹Tc^m-RGD in all groups(r values: 0.748, 0.709, both P < 0.05). Histopathology results showed that the plaques had rich macrophages and a small amount of smooth muscle cells in group C, little macrophages in group B, while no macrophages in group A. Conclusion: ¹⁸F-FDG PET/CT might be an effective noninvasive method for early assessment of aortic vulnerability to atherosclerotic plaque. (authors)

[en] Objective: To investigate the feasibility of a novel molecular probe ⁹⁹Tc^m-3P4-RGD₂ in evaluating arterial plaque stability alter atorvastatin intervention in rabbits with SPECT/CT. Methods: Eighteen male New Zealand rabbits were randomly divided into group A (stable plaque), group B (vulnerable plaque), and group C (vulnerable plaque with statin intervention). All rabbits wee fed with high-fat food for 12 weeks. After high-fat feeding for two weeks, sham surgery was performed on group A. In the meantime, abdominal aorta injury was performed on group B and group C. After that, rabbits of group C were given oral atorvastatin (2.5 mg·kg^-1·d^-1). ⁹⁹Tc^m-3P4-RGD₂ SPECT/CT imaging was performed on each group at the end of 4, 8 and 12 weeks. T/NT ratios were calculated. Animals were sacrificed at the end of 12 week after imaging studies. The abdominal aortas were collected, imaged with SPECT/CT, and evaluated by pathological HE staining and immunohistochemical analysis. MVD was calculated. Differences among 3 groups were analyzed using one-way analysis of variance. Results: There was no significant radioactive uptake in the abdominal aortas of three groups on the 4th week's imaging. The radioactive uptake in abdominal aortas increased slightly on the 8th week, with the highest radioactive uptake in group B. The radioactivity in abdominal aortas of the 3 groups maintained increasing on the 12th week, with T/NT ratios of 1.579 ± 0.217, 1.873 ± 0.226 and 1.524 ± 0.237, respectively (F = 8.984, P < 0.05). In ex vivo abdominal aorta images, especially images of group B, radioactivity in lesion sites was higher than that in normal tissue. Accordingly, results of HE staining showed that artery plaques of group A and group C were grade II and group B was grade IV. The MVD of group A, B and C was 8.17 ± 1.17, 15.86 ± 1.07 and 7.17 ± 1.60, respectively (F = 90.36, P < 0.05). Conclusion: ⁹⁹Tc^m-3P4-RGD₂ SPECT/CT imaging has a high sensitivity in the evaluation of arterial plaque stability after statin intervention in rabbits. (authors)