Magnetic Evaluation Dog Heart Damage Of Radioactive Nuclear Experimental Research

ObjectiveApplication of advanced imaging technology to observe canine heart cardiacstructure, function and myocardial perfusion after radiation injury, the change ofmyocardial activity, etc, for thoracic tumor radiotherapy in patients with earlyprevention of cardiac injury to provide indirect basis and useful information.Methods1.Equipment and drugs: equipment for the German Siemens Sonata1.5T mriscanner, the heart of the special surface of phased-array coil, heart switchcontrol.Drugs: drugs for3%pentobarbital sodium, contrast agents for gadoliniuminjection for acid meglumine (Gd-DTPA).2.Experimental animals and irradiation method take adult male healthy beagleonly8,12.0±0.67kg weight, age1, animals by the anhui province port Yang cityd optical lab, radiation protection institute animal center in China for standardizationfeeding experimental dogs.Exposure dose for single20gy.3.Scanning methods: before irradiation, irradiation after half a year, one year afterirradiation for cardiac MRI scan experimental dogs.With3%pentobarbital sodiumanesthesia experimental dogs (1ml/kg), the skin, lie on your back fixed in a vacuummat, set his mind at to switch control.Sweep canine heart form and function, and thensweep myocardial perfusion, delayed10to15minutes for active scan.Toconventional axial, coronal scan and.(1). Dogs heart left ventricular morphology andfunction of scanning, using true FISP sequences two cavity, three cavity, fourchamber, short axis, film scanning.Left ventricular morphology scan parameters: TR418ms, TE1.1ms, turn Angle of15o,6mm, with a thick layer of layer spacing0mm, view (FOV)350mm x350mm.Left ventricular function (scan) scan parameters:TR43.5ms and1.5ms, TE turn corner15o,6mm, with a thick layer of layerspacing0mm, view (FOV)297mm x340mm.After the scan is complete to push the image to the workstation for image analysis.(2), left ventricular short axis amyocardial perfusion scan: using EPI sequence short axial scanning, scanningparameters: TI100ms, TR188ms, TE1.0ms,15o Angle, FOV309mm x380mm,the scanning time to about40s,50each layer scanning phase, when a singlebreathless scan.Scanning after the start of5-10s with high pressure syringe afterelbow intravenous contrast agent, contrast medium for gadolinium injection acidmeglumine (Gd-DTPA), injection speed of5ml/s, total0.10.2tendency/kg,according to collect first obsolete myocardial perfusion MR images.(3) leftventricular delayed scan: elbow gadolinium injection intravenous contrast agent foracid meglumine8ml, injection speed of1ml/s, ten minutes after injection of contrastagent (active) to delay scan.Sequence variables: TI300ms, TR700ms;TE ms4.2,the average number of times:1times;Number of incentive:1times;The Angle of30o;Scanning direction: two cavity, four cavity and short axis;Thick6mm;Layerspacing of1.6mm;FOV308mm*340mm;Phase encoding direction: A>> P;Sweeptime (s):19s.4.Nuclear magnetic heart heart film scanning image analysis would transmit theimage to the workstation, observe whether local ventricular wall motion decreases orreverse movement.Low signal region perfusion image to observe whether there isirregular hypoperfusion (representative), and records the time signal intensitycurve.Myocardial activity to observe whether there is delayed enhancement imaging,and record the optimal time delayed enhancement.By three line without knowledge ofthe clinical data of radiologists double-blind independent observation analysis, basedon consensus judgment standard.Result1. The canine heart before radiotherapy, radiotherapy after half a year, one yearafter radiotherapy heart, film, pericardium, the activity of myocardial perfusion, theresults are as follows:1.1Films and pericardium heart changed: Radiation therapy, radiation therapy,the second half before heart film no cardiac motion is abate, occurred afterradiotherapy1year only heart movement function abate, sensitivity of 12.5%.Pericardium has no obvious abnormal signal before radiotherapy, radiotherapypericardial effusion was later only2,6pericardial effusion was only a year afterradiotherapy, the sensitivity was75%.Myocardial no obvious abnormal signal beforeradiotherapy, radiotherapy late1only appear high signal,3high signal, a year afterradiotherapy sensitivity was37.5%.1.2First perfusion, myocardial activity: experimental canine heart not seenperfusion defects before radiotherapy, radiotherapy after half a year one myocardialhypoperfusion area, there are7appears only after a year of radiation hypoperfusionarea, the sensitivity was87.5%.No delay to strengthen experimental canine heartbefore radiotherapy, radiotherapy after half a year only delay1reinforcement, a yearafter radiotherapy have5only delay to strengthen, the sensitivity is62.5%.2. The cardiac mri, echocardiographic heart function parameters and compared.2.1Later on cardiac mri cardiac function parameters: before radiotherapy,radiotherapy, radiotherapy after a year of nuclear magnetic measured left ventricularcardiac function parameters, LVEF value respectively (40.95±5.55)%,(38.47±9.38)%,(27.92±10.84)%.EDV values of respectively (21.28±3.65)ml,(23.85±6.54)ml,(31.12-7.65) ml.ESV values of respectively (11.85+2.02)ml,(12.10+4.74)ml,(21.55-5.37) ml.EF, EDV, ESV later compared with before radiotherapy,radiotherapy P>0.05, no statistical significance.EF, EDV, ESV year afterradiotherapy compared with before radiotherapy, P <0.05, with statisticalsignificance.Explain EF year after radiotherapy is reduced before radiotherapy, EDV,ESV radiotherapy after one year than before radiotherapy.EF, EDV, ESV second halfa year after radiotherapy and radiotherapy, P <0.05, with statisticalsignificance.Explain EF year after radiotherapy is radiation decreased later, EDV,ESV radiotherapy after the radiation later increase in a year.2.2Echocardiographic heart function parameters: the cardiac functionparameters: before radiotherapy, radiotherapy, radiation therapy, the latter part of thisyear after ultrasonic measured left ventricular cardiac function parameters, LVEFvalue (40.32±5.12)%,(37.18±7.44)%,(27.87±7.44)%.EDV values ofrespectively (21.27±3.16) ml,(23.40±5.36)ml,(33.18±5.59) ml.ESV values of respectively (11.27±1.65) ml,(11.67±3.64)ml,(22.18±2.70)ml.EF, EDV, ESV later compared with before radiotherapy, radiotherapy P>0.05,no statistical significance.EF, EDV, ESV year after radiotherapy compared withbefore radiotherapy, P <0.05, with statistical significance.Explain EF year afterradiotherapy is reduced before radiotherapy, EDV, ESV radiotherapy after one yearthan before radiotherapy.EF, EDV, ESV second half a year after radiotherapy andradiotherapy, P <0.05, with statistical significance.Explain EF year after radiotherapyis radiation decreased later, EDV, ESV radiotherapy after the radiation later increasein a year.3.Nuclear magnetic cardiac function compared with ultrasonic heart function:before radiotherapy, radiation therapy, the second half, a year after radiotherapynuclear magnetic cardiac function compared with ultrasonic cardiac function, P>0.05;Nuclear magnetic radiation therapy after heart and the heart of ultrasonic testingof EF, EDV, ESV difference is not significant.Conclusion1. This topic through the research proves that cardiac mri evaluation of chesttumor radiotherapy on heart function damage sensitivity, high specificity andaccuracy of noninvasive detection methods.2. Cardiac imaging can from the heart structure, function, perfusion, active allaspects of radioactive damage was assessed.3. Evaluation of radioactive cardiac injury on cardiac function in cardiacimaging compared with cardiac ultrasound has no obvious advantage, but in the showheart structure and myocardial perfusion, active ultrasonic cardiac mri is superior tothe heart.