Cardiovascular MRI

Cardiovascular MRI is an MRI scan of the heart and peripheral blood vessels. In addition to the commonly used horizontal, coronal, and sagittal planes, the scan can also use the long axis of the heart perpendicular to the septum, parallel to the septal heart. The long axis position and the short axis image of the heart perpendicular to the interventricular septum to fully display the anatomy of the heart. The patient enters the examination room and is scanned for examination before the MRI examination instrument. Basic Information Specialist Category: Cardiovascular Examination Category: Nuclear Magnetic Resonance Applicable gender: whether men and women apply fasting: not fasting Tips: Install artificial heart pacemakers and nerve stimulators. There are silver clips in the skull and metal foreign bodies in the eyeball. Metal objects (such as internal fixed steel nails) can not be inspected in various critically ill patients. Pregnant women should be examined carefully, and if they are pregnant, please inform the doctor. Normal value 1. The horizontal axis scan plane is perpendicular to the long axis of the body. 2. The coronal scanning plane is parallel to the coronal plane of the body. 3. The sagittal scan plane is parallel to the sagittal plane of the body. 4. The long axis of the heart perpendicular to the interventricular septum is tilted about 20 to 45 degrees from the transverse axis of the heart parallel to the interventricular septum. The centerline is scanned through the aortic root and apex. Four heart chambers can be displayed on the same level, which can be compared with the four-chamber heart position of the ultrasound. Can well observe the interatrial septum, ventricular septum, mitral and tricuspid valve, left ventricular anterior wall, lateral wall and apex and bottom of the myocardium, left and right ventricular outflow tract, ascending aorta and main pulmonary artery. It can be used to observe the functional status of the mitral and tricuspid valves, to measure changes in myocardial thickness, left ventricular length and short axis, and cardiac function. 5. The long axis of the heart parallel to the interventricular septum raises the right side of the human body by 30 to 50 degrees, so that the interventricular septum is parallel to the examination bed, and then the coronary scan can be performed. It is equivalent to the oblique position parallel to the interventricular septum. The image is similar to a cardiovascular image with a right anterior oblique 30 degrees. The right atrium, right ventricle or left atrium, left ventricle can be displayed on the same level to fully observe the relationship between the atrioventricular, better showing the anterior wall, the inferior wall, the apex and the bottom of the heart. This position can accurately measure cardiac function (end-diastolic and end-systolic volume, left-hearted ejection fraction), and measure left and right ventricular long-axis and short-axis, which can be compared with left ventricular angiography. Left ventricular outflow tract, aortic root, main pulmonary artery, right pulmonary artery, left superior pulmonary vein, posterior group papillary muscle, etc. Rapid imaging allows observation of functional changes in the mitral valve. 6. The short axis of the heart perpendicular to the interventricular septum is an image obtained by sagittal scanning on the horizontal axis of the test chamber parallel to the horizontal axis of the examination bed, which corresponds to the oblique position perpendicular to the interventricular septum on the supine horizontal axis. image. Controlled with a 60-degree left anterior oblique cardiovascular image. The atrioventricular septum is just to separate the left and right atrium and the left and right ventricles symmetrically. The same level can be shown in the left and right ventricles or left and right atria, and the atrioventricular septum, anterior wall, lateral wall, inferior wall, posterior wall myocardium, right ventricular outflow tract, etc., as well as aortic ascending, arch, descending and branches thereof can be observed. Clinical significance Abnormal result 1. Myocardium: In the spin echo sequence, the myocardium and the striated muscle resemble a medium signal intensity. Myocardial thickness is measured using the long axis and short axis of the heart perpendicular to the septum and the long axis of the heart parallel to the septum. Normal left ventricular myocardium thickness increases by at least 30% during systolic phase compared with diastolic phase. According to reports, in Chinese normal people, the left ventricular wall diastolic thickness of the lateral wall male is 12.1~14.1mm, female is 11.2~11.4mm; apical male 15.5mm, female 11.0mm, ventricular septal male 11.1~11.7mm??10.6~12.2 The menstrual thickening rate of mm was 24.3%~31.2% in males and 24.8%~30.0% in females. The rate of ventricular septal thickening was 24.7%~36.5% in males and 32.8%~38.7% in females. 2, endocardium: a smooth, transparent membrane inside the heart chamber, continuous with the large intima and valve. It is often difficult to distinguish the thin line whose signal is slightly higher than the myocardium. 3, atrium: the right atrial ear is a base wide triangle, and the right atrial inner heart cavity between the continuous width; left atrial appendage is tubular, narrow connection with the left atrium. The superior and inferior vena cava enter the right atrium in the transverse position, and are easily recognized in the coronal and sagittal positions. The size of the left and right atrium can be accurately determined on the MRI. 4, ventricle: the ventricle consists of the entrance, ventricular trabeculae and outflow. The right ventricle is triangular, the trabecular muscle is thick, the inner wall is rough, there is an adjustment bundle, and the atrioventricular valve is close to the apex. The left ventricle is elliptical, the inner wall is smooth, the trabecular muscle is slender and unregulated, and the atrioventricular valve is far from the apex. Due to the airflow effect in the ventricular cavity, no signal is generally visible. 5, valve: the valve and the atrial septum are similar to the medium signal, slightly higher than the myocardial signal, the body coil can roughly see the shape of the valve, the heart surface coil can clearly show the mitral, tricuspid and semilunar valves. 6, pericardium: due to the long T1 of the fibrous tissue T2 and low proton density, the pericardium is low signal. On the MRI, only the fibrous cystic part of the pericardium has sufficient thickness to display, and the contrast between the surrounding high-signal fat and the medium-signal myocardium appears as a low-signal arc shadow between the two. The pericardium is often displayed on the anterior surface of the right ventricle, but the posterior lateral and right atrial regions of the left ventricle are unclear because the adipose tissue is less, the pericardium is unclear, and it is difficult to distinguish from the surrounding low-signal lung tissue. 7, coronary artery: ECG gating and heart surface coil, coronary artery can be seen at different scanning levels. Coronary arteries on MRI showed under-stability and poor reproducibility. Although coronary artery calcification is important in the diagnosis of coronary heart disease, MRI is difficult to distinguish between calcified and unsignalized blood flow. Electron beam CT can satisfactorily show coronary artery calcification. People who need to be examined: heart disease patients, people with abnormal chest feelings. Precautions Taboo before inspection: no special contraindications. Requirements for inspection: Check the relaxed mood, follow the doctor's instructions to check, please bring the medical records, X-ray film, CT film, and previous MRI films along with the MRI room for reference. Inspection process Magnetic resonance imaging (MRI) is a new examination technique based on the principle that a magnetic nucleus with a magnetic flux can generate transitions between energy levels under the action of a magnetic field. MRI can help to check the energy state and cerebral blood of the brain of patients with epilepsy. The flow situation is of great value in the diagnosis of degenerative diseases. MRI is realized by the action of external high-frequency magnetic field, which generates signals from the body material to the surrounding environment. The imaging process is similar to image reconstruction and CT, except that MRI does not rely on external auxiliary radiation, absorption and reflection, nor radioactivity. The gamma-assisted radiation of matter in the body is imaged by the interaction of an external magnetic field and an object, and the high-energy magnetic field is harmless to the human body. So MRI is safe. The patient enters the examination room and is scanned for examination before the MRI examination instrument. Not suitable for the crowd Inappropriate crowd: 1. Those who install artificial heart pacemakers and nerve stimulators are forbidden to check. 2. It is forbidden to check if there is a silver clip in the skull and a metal foreign object in the eyeball. 3. The ECG monitor cannot enter the MRI examination room. Those who have undergone arterial surgery, have had heart surgery and have an artificial heart valve are forbidden to check. 4, a variety of critically ill patients: such as coma after trauma or accident, irritability, arrhythmia, respiratory insufficiency, constant blood loss and incontinence and so on. 5. Metal objects (such as internal fixed steel nails) cannot be inspected at the inspection site. 6. Pregnant women should be examined carefully. If they are pregnant, please inform the doctor. Adverse reactions and risks Nothing.