Objective To investigate the imaging characteristics of USPIO-enhanced and Gd-enhanced MRI in atherosclerosis and to compare the detection rate of atherosclerotic plaque between them. Methods Thirty-five healthy male rabbits were assigned to experimental group (n=30) to establish a model of atherosclerosis by damaging aortic tunica intima with Foley′s tube in combination with a high fat diet and 5 to control group without any intervention. At week 12, USPIO-enhanced and Gd-enhanced MRI scanning were conducted to compare the signal changes of atherosclerotic plaque before and after enhancement with the 2 contrast media. Ninety seven pictures were randomly selected respectively from the pictures enhanced by the 2 contrast media to compare the detection rate plaque between them. Pthology examination was used for detection standard. For the control group , pictures were randomly selected. Results In the experimental group, 7 rabbits died of Foley′s tube damaging, 2 died of raising and 1 died of anesthesia. All 5 rabbits in control group survived. A total of 172 pathological sections were made with 134 plaques and 72 vulnerable plaques pathologically confirmed. In pictures enhanced by USPIO , 84 plaques were confirmed by HE staining with a detection rate of 86.6%. In pictures enhanced by Gd, 72 plaques were confirmed by HE staining with a detection rate of 74.2%. Detection rate of USPIO-enhanced MRI in atherosclerosis plaque was significantly higher than that of Gd-enhanced MRI (X2=3.96, P=0.046). Conclusion USPIO shows its superiority as a new contrast medium in detection of atherosclerosis plaque.

OBJECTIVETransesophageal echocardiography was performed during closed-chest cardiopulmonary resuscitation (CPR) in in-hospital cardiac arrest to further explore the hemodynamic mechanism of CPR.

METHODSCPR attempts were performed according to advanced cardiovascular life support guidelines in 6 cases of in-hospital cardiac arrest. Multi-plane transesophageal echocardiography was carried out within 15 min of initiation of CPR. Throughout CPR, the motion of the mitral, tricuspid and aortic valves, the changes in the left ventricular cavity size and the thoracic aortic diameter were observed. Trans-mitral and trans-aortic Doppler files of blood flow were also documented.

RESULTSA closure of the mitral and tricuspid valves with simultaneous opening of the aortic valve occurred exclusively during chest compression, resulting in forward blood flow in the pulmonary and systemic circulation. Peak forward aortic flow at a velocity of 58.8 +/- 11.6 cm/s was recorded during the compression phase. Whereas, a closure of the aortic valve and rapid opening of the atrioventricular valves associated with ventricular filling during relaxation of chest compression was noted in all 6 patients. Peak forward mitral flow at a velocity of 60.6 +/- 20.0 cm/s was recorded during the release phase. Mitral regurgitation during the chest compression period was detected in 5 patients, reflecting a positive ventricular-to-atrial pressure gradient. A reduction in the left ventricular chamber and an increase in the thoracic aortic diameter during the compression phase was found in all patients, indicating that direct cardiac compression contributed to forward blood flow.

CONCLUSIONThese observations favor the cardiac pump theory as the predominant hemodynamic mechanism of forward blood flow during CPR in human beings.

Aged ; Aged, 80 and over ; Cardiopulmonary Resuscitation ; Echocardiography, Transesophageal ; Female ; Heart Arrest ; diagnostic imaging ; physiopathology ; therapy ; Hemodynamics ; Humans ; Male ; Middle Aged

In the early 1990's, emergency percutaneous transluminal coronary angioplasty (PTCA) has been proven to be the best strategy for acute myocardial infarction (AMI). It has not only resulted in a higher vascular recanalization, but has also further reduced mortality and morbidity, and has greatly improved life quality of patients with AMI.Objective To investigate the effect of emergency PTCA in AMI.Methods Emergency PTCA was performed in 52 AMI patients (male: 43, female: 9) from October 1993 to December 1997 in our hospital. The patients were aged between 31-89 years (±s, 53.7±8.2). Among them, 25 had anterior infarction, 27 inferior infarction. Angiographically infarct-related vessels were left anterior descending artery (LAD) in 27 cases, right coronary artery (RCA) in 22, and left circumflex artery (LCx) in 3. The mean time from the onset of chest pain was 6.12±5.13 h (2-12 h). Primary PTCA (balloon angioplasty without previous thrombolytic therapy) was performed in 34 cases, and rescue PTCA (balloon angioplasty after previous thrombolytic therapy that had failed to restore blood flow) in 15 cases, and immediate PTCA ( balloon angioplasty after previous successful thrombolysis but with severe residual stenosis and reoccurring angina pectoris) in 3 cases. Only the infarct-related vessels was dilated during emergency PTCA which is similarto conventional balloon angioplasty. All patients were given aspirin of 250 mg/d and were heparinized during the first 3-5 days after PTCA. Ticlopidine (250 mg, twice daily) was also given for 3 months if patients had experienced intracoronary stenting.Results Emergency PTCA was successfully performed in 48 of 52 patients (33/34 in primary PTCA, 12/15 in rescue PTCA, and 3/3 in immediate PTCA) which accounts for the initial success rate of 92%. Intracoronary stents were implanted in 18 of the 48 patients due to the presence of different vessel complications. PTCA was failed in 4 patients (3 occurred in rescue PTCA, 1 occurred in primary PTCA). Among the patients, one died of acute pulmonary edema during the rescue PTCA procedure, one had acute reocclusion after rescue PTCA and died of acute pump failure within 24 h. Guiding wire failed to put through lesions in the other 2 patients. Mass intracoronary thrombosis was present in 5 of 34 patients after primary PTCA despite the restoration of TIMI 3 grade blood flow in the distal segment. The residual thrombosis disappeared after urokinase (500 000-1 500 000 IU) was infused into the culprit coronary.Conclusions Clinical studies have suggested that emergency PTCA is more effective in early reperfusion than that of thrombolysis in AMI. Though emergency PTCA is highly effective, but the initial success rate is lower than that of conventional PTCA with a higher complication and mortality. Thus it should be only steadily introduced into AMI.

OBJECTIVETo investigate the feasibility of Ultrasmall superparamagnetic iron oxide-enhanced magnetic resonance angiography (USPIO-MRA) combined with interleukin-6 (IL-6) and IL-10 detection for detecting atherosclerotic plaques in rabbits.

METHODSTwenty-four normal male rabbits were randomly assigned (n=8) into group A with atherosclerosis induced by damaging the aortic tunica intima with Foley's tube in combination with a high fat diet, group B with a high fat diet, and group C without any intervention. At week 12, plain and USPIO-MRA was performed in all the 24 rabbits and the results were compared with pathological examinations; blood samples were collected from the ear vein to examine blood lipids and levels of IL-6 and IL-10.

RESULTSThe rabbits in groups A and B showed significantly different IL-6 levels (167 ± 21.3 vs 116 ± 14.3 pg/ml, P<0.05) but comparable blood lipids and IL-10 levels (P>0.05). The levels of IL-6, IL-10, TC, TG, and LDL, but not HDL, differed significantly between groups A and C and between groups B and C (P<0.01). Continuous MRA scan showed significantly different signal-to-noise ratios (SNR) between the 3 groups.

CONCLUSIONUSPIO-MRA combined with IL-6 and IL-10 detection is feasible in detecting atherosclerotic plaques in rabbits.

Animals ; Atherosclerosis ; Contrast Media ; Dextrans ; Interleukin-10 ; analysis ; Interleukin-6 ; analysis ; Magnetic Resonance Angiography ; Magnetite Nanoparticles ; Male ; Plaque, Atherosclerotic ; diagnosis ; Rabbits